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African hair growth parameters
Abstract
Hair growth parameters have been studied mostly in caucasian hair, whereas few data on African hair have been reported in the literature.
To evaluate hair growth characteristics of African volunteers born in Africa.
Thirty-eight young adults (19 women, 19 men, mean +/- SD age 27 +/- 10 years), native of central and western Africa, took part in the study. Phototrichograms were performed in order to record three parameters of hair growth: hair density, telogen percentage and rate of growth. For each volunteer, three regions of the scalp, namely vertex, temporal and occipital areas, were assessed.
Hair density varied from 90 to 290 hairs cm(-2), with higher counts on the vertex. No significant difference between men and women was recorded. Telogen percentage showed wide variations, from 2 to 46%, with higher levels on the temporal area and in men. The rate of growth fluctuated from 150 to 363 microm day(-1) with no difference related either to gender or to scalp region. These data were compared with those previously obtained in caucasian volunteers of comparable age, and showed significant differences between the two ethnic groups in all three parameters studied. Hair density in African volunteers was lower than that in caucasians (mean +/- SD 190 +/- 40 and 227 +/- 55 hairs cm(-2), respectively). African hair grew at a much slower rate than caucasian hair (mean +/- SD 256 +/- 44 vs. 396 +/- 55 microm day(-1)), and telogen counts were frequently higher in African hair (mean +/- SD 18 +/- 9% vs. 14 +/- 11%).
This study demonstrated significant differences between African and caucasian hair growth parameters, which might suggest a trend towards increased hair loss in Africans, even though it contrasts with a lower and slower incidence of the development of alopecia in Africans.
... Hair growth occurs in three phases: growth (anagen), cessation (catagen), and rest (telogen) [11]. Historically hair cortisol research has relied on the generally accepted assumption that hair growth occurs at a fairly constant rate of approximately 1 cm per month, with some individualistic and ethnic variability [12][13][14][15]. This growth rate has allowed for the assessment of average cortisol levels over time. ...
... As hair cortisol research has advanced it has become apparent that this growth rate is not nearly as constant as previously thought. In a study of ethnic hair growth rates Loussouarn et al. (2001) found that individuals of African descent have a slower growth rate (256 ± 44 μm per day) than Caucasians (396 ± 55 μm per day) [12]. While comparing hair growth parameters in 24 human ethnic groups Loussouarn et al. (2005Loussouarn et al. ( , 2016 confirmed again that individuals of African descent have slower hair growth than Caucasians, and further reported that individuals with an Asian background have hair that grows faster than both African and Caucasian hair [16,17]. ...
... As hair cortisol research has advanced it has become apparent that this growth rate is not nearly as constant as previously thought. In a study of ethnic hair growth rates Loussouarn et al. (2001) found that individuals of African descent have a slower growth rate (256 ± 44 μm per day) than Caucasians (396 ± 55 μm per day) [12]. While comparing hair growth parameters in 24 human ethnic groups Loussouarn et al. (2005Loussouarn et al. ( , 2016 confirmed again that individuals of African descent have slower hair growth than Caucasians, and further reported that individuals with an Asian background have hair that grows faster than both African and Caucasian hair [16,17]. ...
Background:
Hair cortisol analysis is increasingly being appreciated and applied in both research and medicine, aiding endocrinologists with diagnosis.
Content:
We provide an overview of hair cortisol research in general and an update on methodological considerations including the incorporation of cortisol into hair, hair growth rates, and sampling procedures, mincing vs. grinding of samples during preparation for extraction, various extraction protocols, and quantification techniques. We compare the clinical utility and application of hair cortisol with traditional methods of measurement while acknowledging the limitations of analysis including variations in hair growth parameters. We explore the value of hair cortisol in cases of Cushing syndrome (particularly Cyclical Cushing), Adrenal insufficiency (including Addison's disease), therapy monitoring, cardiovascular disease, stress, and mental illness.
Summary:
Hair cortisol provides a unique objective biomarker for the analysis of endogenous cortisol levels for not only clinical diagnostic purposes but also in research. The use of hair cortisol has great potential for advancing patient care.
... There is a paucity of literature on hair density within the Hispanic population [3]. While previous research has shown that individuals of African descent have lower hair density compared with Caucasians, less is known about how hair density in the Hispanic population compares with other ethnicities [4,5]. Establishing normative values can help better identify the presence of disease and provide a useful baseline or target when researching and treating hair loss in this patient population. ...
... Using the phototrichogram technique, Loussouarn et al. [3] reported an overall hair density mean ± SD of 215 ± 68/cm 2 in a cohort from Mexico (mean age 26 years) and 208 ± 65/cm 2 in a cohort from Latin America (mean age 27 years). In a different study, Loussouarn [5] evaluated hair density in African Americans and Caucasians (mean age 27 and 28 years, respectively, hair density mean ± SD of 190 ± 40 and 227 ± 55/ cm 2 , respectively). In both groups, they observed a higher hair density at the vertex compared with the temporal and occipital scalp and also noted a decrease in hair density in subjects over the age of 35 years [5]. ...
... In a different study, Loussouarn [5] evaluated hair density in African Americans and Caucasians (mean age 27 and 28 years, respectively, hair density mean ± SD of 190 ± 40 and 227 ± 55/ cm 2 , respectively). In both groups, they observed a higher hair density at the vertex compared with the temporal and occipital scalp and also noted a decrease in hair density in subjects over the age of 35 years [5]. Our patient cohorts' higher average age may explain the lower values we obtained as compared with these prior studies. ...
Background:
There is limited research into normative hair density values in individuals of Hispanic descent.
Methods:
In order to help establish baseline density values in these individuals, we evaluated the hair density in 99 Americans of Hispanic descent and compared them with the values in 44 individuals of African descent and 23 Caucasians. Participants were recruited from a New York City medical center and self-identified their ethnicity. Biracial individuals were excluded from the study.
Results:
The hair density means ± SD ranged from 169 ± 31 to 178 ± 33/cm2 in Americans of Hispanic descent, from 148 ± 25 to 160 ± 27/cm2 in individuals of African descent, and from 214 ± 28 to 230 ± 33/cm2 in Caucasian individuals. All differences in hair densities between the ethnicities were statistically significant (p values ranging from 3.03 × 10-14 to 0.0249).
Conclusion:
While trichoscopy is not as accurate as invasive histological assessment of hair density or phototrichogram, it is still a reliable and fast method for assessing hair density. Increased awareness of ethnic variances in hair density can help clinicians and researchers diagnose hair disorders, monitor response to therapy, and conduct hair-related research in these patients.
... Abnormal cortisol concentrations may result from stimuli such as fear, hypoglycemia, fever, trauma, shock, and despair. In abnormal states of the HPA axis, increased or decreased cortisol values may be obtained [8]. Tumors of the adrenal gland and ectopic or pituitary adrenocorticotrophic hormone-producing cancers are commonly correlated with overproduction of cortisol (Cushing's syndrome), while adrenal paucity may result in under-production of cortisol (Addison's disease) [5]. ...
... Following removal of methanol, the sample is resuspended in 150-250 μL of buffered saline at pH 8.0. Samples are mixed for one minute followed by another 30 seconds until they are well vortexed [8]. The cortisol in the hair samples is the assayed using the Salivary ELISA Cortisol kit© (Alpco Diagnostics®, Windham, NH) as per the manufacturer's directions. ...
... Hair cortisol levels are not able to determine brief cortisol responses, and cannot be used to determine day-to-day variation. It is not known whether hair cortisol levels vary with hair growth rate, which could be important as the activity of hair follicles is intermittent, consisting of active phase (anagen), transitional (catagen) and resting phase (telogen) [8]. Further, hair growth rate decreases with age, in various diseases (for example, hyper-and hypothyroidism) and varies among ethnic groups. ...
The veterinarian is daily faced with the challenge of diagnosing several disease conditions in different animals. Quantifying cortisol levels has been used in the evaluation of anxiety and distress initiated by infectious and non-infectious disease conditions, mismanagement, transportation, adverse environmental temperature and surgical operations. The hormone-cortisol has been implicated in several immunologic and metabolic processes and can thus serve as a marker to monitor animal welfare. Several factors affect the specific test to be carried out and which sample is to be used. Recently, RIA has been identified as the gold standard for determination of cortisol levels. However it also has its own short comings hence the need to utilize other assay techniques such as ELISA, fluorescence techniques and chemical assays which are more common in our environment. There is also prospect for the analysis of cortisol using non-invasive samples such finger nails as well as ear wax for enhanced test results.
... Therefore, measurement of cortisol in hair further away from the hair bulb may provide a linear record of past average cortisol concentrations in the body. Hair on the human head grows at approximately 1cm/month (Loussouarn 2001). The growth rate of human hair has previously been used in archaeological and forensic samples to enable the reconstruction of the timing of consumption of food, drugs, alcohol and exposure to pollutants (Cartmell, Aufderheide et al. 1991;Parsche, Balabanova et al. 1993;White 1993;Baez, Castro et al. 2000). ...
... Hair on various parts of the body grows at different rates (see table 2 for details), with scalp hair being the fastest (Scalp > pubic > axillary > beard, women > men, Caucasian > Asian, (Harkey 1993)). It has an average growth rate of approximately 397 µm/d or 1.2 cm/month in Caucasians (Loussouarn 2001). The growth rate varies with ethnic background, diet, hormonal status, pregnancy, the time of year and gender, with the scalp hair of women growing faster than that of men (Ebling 1987;Harkey 1993;Loussouarn 2001;Krause and Foitzik 2006;Randall 2007). ...
... It has an average growth rate of approximately 397 µm/d or 1.2 cm/month in Caucasians (Loussouarn 2001). The growth rate varies with ethnic background, diet, hormonal status, pregnancy, the time of year and gender, with the scalp hair of women growing faster than that of men (Ebling 1987;Harkey 1993;Loussouarn 2001;Krause and Foitzik 2006;Randall 2007). Interestingly for the purposes of this work, it has been discovered that cultured human hair follicles have the ability to synthesize cortisol using the same enzymes as present in the adrenal glands, mimicking the central HPA-axis (Ito, Ito et al. 2005). ...
... White children who provided hair samples at the mid-childhood (n = 639) or early adolescent in-person visits (n = 567) were eligible for the present study. We excluded non-white children because of differences in hair texture and hair growth rate by race/ethnicity [21], which may make HCC measurements across racial and ethnic groups incomparable. There were too few participants in strata of non-white racial/ethnic groups who provided hair samples to perform analyses stratified by race (n = 96 black participants; n = 40 Asian participants; n = 38 Hispanic participants). ...
... However, our study has limitations as well. First, because of differences in hair growth and texture between racial and ethnic groups [21], we analyzed all associations within strata of race/ethnicity. However, few black, Hispanic, and Asian participants provided hair samples, and so we excluded them from our analyses. ...
Background
Hair cortisol concentration (HCC) is an increasingly used measure of systemic cortisol concentration. However, determinants of HCC in children and adolescents are unclear because few prospective studies have been conducted to date.
Study design
We followed 725 children in Project Viva, a pre-birth cohort study of mothers and children, who provided hair samples at mid-childhood (median age: 7.7 years) or early adolescence (median age: 12.9 years). We examined associations of various factors measured from pregnancy to mid-childhood with HCC in mid-childhood and early adolescence, as well as change in HCC between these time points (ΔHCC).
Results
There were 426 children with HCC measurements in both mid-childhood and early adolescence, 173 children with measures only in mid-childhood, and 126 with measures only in early adolescence. HCC was lower in mid-childhood (median 1.0pg/mg [interquartile range, IQR: 0.5, 2.4]) than early adolescence (2.2pg/mg [1.1, 4.4]). In multivariable-adjusted regression models, female sex (β = -0.41, 95% CI: -0.67, -0.15) and birth weight-for-gestational age z-score (β = -0.19, 95% CI: -0.33, -0.04) were associated with lower mid-childhood HCC, while prenatal smoking was associated with higher mid-childhood HCC (β = 0.53, 95% CI: 0.04, 1.01). In early adolescence, child age (β = 0.34 per year, 95% CI: 0.21, 0.46) female sex (β = 0.33, 95% CI: 0.10, 0.57), and maternal pre-pregnancy body mass index (β = 0.15 per 5-kg/m², 95% CI: 0.01, 0.29) were positively associated with HCC. Child anthropometric measures and biomarker concentrations were not associated with HCC.
Conclusion
Maternal pre-pregnancy BMI, maternal prenatal smoking, and low birth weight were associated with higher mid-childhood and adolescent HCC. However, few postnatal characteristics were associated with HCC.
... A small number of families included 2 sibling participants, thus we randomly excluded one sibling from each sibling pair using a random number generator in statistical software, which excluded an additional 14 children. Data from children of all races/ethnicities was included for the cord blood analyses, but due to the potential that variation in hair growth rates and textures by race/ethnicity may affect cortisol assays, only white children were included in the hair cortisol analyses [33]. Mothers reported on child race/ethnicity in early childhood, and we imputed missing values with maternal race/ethnicity. ...
Background
Prior studies have reported conflicting results regarding the association of prenatal maternal depression with offspring cortisol levels. We examined associations of high levels of prenatal depressive symptoms with child cortisol biomarkers.
Methods
In Project Viva (n = 925, Massachusetts USA), mothers reported their depressive symptoms using the Edinburgh Postnatal Depression Scale (EPDS) during pregnancy, cord blood glucocorticoids were measured at delivery, and child hair cortisol levels were measured in mid-childhood (mean (SD) age: 7.8 (0.8) years) and early adolescence (mean (SD) age: 13.2 (0.9) years). In the Generation R Study (n = 1644, Rotterdam, The Netherlands), mothers reported depressive symptoms using the Brief Symptom Inventory (BSI) during pregnancy, and child hair cortisol was measured at a mean (SD) age of 6.0 (0.5) years. We used cutoffs of ≥ 13 for the EPDS and > 0.75 for the BSI to indicate high levels of prenatal depressive symptoms. We used multivariable linear regression models adjusted for child sex and age (at outcome), and maternal pre-pregnancy BMI, education, social support from friends/family, pregnancy smoking status, marital status, and household income to assess associations separately in each cohort. We also meta-analyzed childhood hair cortisol results from both cohorts.
Results
8.0% and 5.1% of women respectively experienced high levels of prenatal depressive symptoms in Project Viva and the Generation R Study. We found no associations between high levels of maternal depressive symptoms during pregnancy and child cortisol biomarkers in either cohort.
Conclusions
The present study does not find support for the direct link between high levels of maternal depressive symptoms and offspring cortisol levels.
... In this study, the phrase "African hair" will refer to hair of African origin. African hair has a higher hair density than Caucasian and Asian hair [13]. ...
Globally, it is amazing how power is attached to hair in various cultures. Hairstyles and shapes are definitive
social markers used in determining, among other things ethnicity, religion, and age in Africa. In Ghana, most
communities, over the years, from generation to generation have used indigenous hairstyles to symbolise and
conserve their traditional socio-cultural beliefs and practices. Hence, the interpretation of art in connection to
indigenous hairstyles cannot be underestimated by every culture. However, many people seem to be ignorant
about the role that the cornrow hairstyle played during the transatlantic slave trade period. People appear to
focus more on the beauty and the aesthetic qualities of the cornrow. The research design used was qualitative.
So, descriptive and content analyses were used to analyse the data collected from the participants.
These five participants (i.e., one indigenous hairstylist, two directors of the Centre for National Culture in
Kumasi, and two curators of Elmina Castle) were purposively selected. In-depth interviews were used to solicit
data from them. The findings of the research revealed the origin of the cornrow, and how the Akans come into
contact with it. Again, the study uncovered the role that Cornrow played in liberating some Africans from
slavery. Based on the conclusion, recommendations about revisiting African roots (to learn and adopt some of
its indigenous practices) were suggested.
... 14 This process leads to the formation of small knots in which combing through would lead to breakage. 14 This spring-back and knotting effect would leave daily combing equitable to that of a daily haircut in individuals with hair types exhibiting high degrees of curl and kink (i.e., hair types such as VI, VII, and VIII.) 14 In addition, studies support that hair types described as African exhibit slower growth than European hair, 14,18,19 leaving the practice of combing to be unpleasant for those wishing to grow hair longer in length. ...
Biological diversity of hair impacts what stress the hair can withstand. This proves to create a gap in care when evaluating over-the-counter products available to treat Pediculosis humanus capitis (head lice) in the United States. The nit comb would not be conducive for use in an individual with African hair, yet all OTC product instructions list the requirement of the nit comb. Lice treatment products provide instructions that are applicable for only specific hair types and do not address treatment recommendations for African hair. The OTC product instructions are outdated and exclusionary. A clear discrepancy and gap in care exists for many Americans seeking self-care treatment of Pediculosis capitis. Pharmacists should remain aware of this discrepancy and counsel on alternative practices such as applying the active formulations in the hair but refrain from utilizing the nit comb following the application of the topical medication.
... The 1,139 mother-child pairs included 251 nonwhite participants who had hair cortisol data available but no data available for any of the cord blood outcomes. Because of differences in hair growth rates and hair textures between individuals of different races that affect the cortisol assay, 33 hair cortisol analyses only included white children. In total, we included 928 pairs in the Project Viva study who were eligible for our current analyses (Supplementary Table S1). ...
Exposure to maternal hyperglycemia in utero has been associated with adverse metabolic outcomes in offspring. However, few studies have investigated the relationship between maternal hyperglycemia and offspring cortisol levels. We assessed associations of gestational diabetes mellitus (GDM) with cortisol biomarkers in two longitudinal prebirth cohorts: Project Viva included 928 mother–child pairs and Gen3G included 313 mother–child pairs. In Project Viva, GDM was diagnosed in N = 48 (5.2%) women using a two-step procedure (50 g glucose challenge test, if abnormal followed by 100 g oral glucose tolerance test [OGTT]), and in N = 29 (9.3%) women participating in Gen3G using one-step 75 g OGTT. In Project Viva, we measured cord blood glucocorticoids and child hair cortisol levels during mid-childhood (mean (SD) age: 7.8 (0.8) years) and early adolescence (mean (SD) age: 13.2 (0.9) years). In Gen3G, we measured hair cortisol at 5.4 (0.3) years. We used multivariable linear regression to examine associations of GDM with offspring cortisol, adjusting for child age and sex, maternal prepregnancy body mass index, education, and socioeconomic status. We additionally adjusted for child race/ethnicity in the cord blood analyses. In both Project Viva and Gen3G, we observed null associations of GDM and maternal glucose markers in pregnancy with cortisol biomarkers in cord blood at birth (β = 16.6 nmol/L, 95% CI −60.7, 94.0 in Project Viva) and in hair samples during childhood (β = −0.56 pg/mg, 95% CI −1.16, 0.04 in Project Viva; β = 0.09 pg/mg, 95% CI −0.38, 0.57 in Gen3G). Our findings do not support the hypothesis that maternal hyperglycemia is related to hypothalamic–pituitary–adrenal axis activity.
... The percentage occurrence of medulla for different anatomical regions decreased in the followed order: pubic, axilla, eyebrow, and scalp. From a slightly different perspective, the growth rate of African hair (256 m/d 44) was reported as signi cantly slower than Caucasian hair (396 m/d 55) (46,47). In a study of female scalp hair, it was previously reported that the medulla of white, nonpigmented hair was more developed than pigmented hair. ...
Synopsis In this study, we investigated differences in the various properties of textured hair as compared to straight hair. As representative hair types from both ends of the spectrum, we investigated the morphological and ultra ne structural characteristics of African and Caucasian hair. We took a profound look at African hair using eld emission scanning electron microscopy (FESEM), examining the exterior of the ber as well as its interior structure by analyzing thin cross-sections of hair. We found that it has unique morphology in both the exterior and interior of the ber. Some key features include the ber morphology at a point of curvature, concavity in the major axis, large distribution of melanin granules, and brillar structures (keratins) heavily coated with biological material (presumably lipids). We further examined the lipid characteristics of African and Caucasian hair using Fourier transform infrared imaging to map the lipid distribution within the cross-section of hair. Using dynamic vapor sorption, we observed the effect of lipid distribution in African hair and its in uence on water management properties. Finally, tensile strength data (break stress, percentage extension at break, etc.) agreed with data previously published in the literature. Expanding on this theme, we monitored the fracture patterns of bers extended to break using FESEM. Overall, African hair was found to exhibit various types of fracture patterns, especially at the point of curvature of the ber. The structures of the broken brillar proteins (intermediate laments) were signi cantly longer in Caucasian hair than in African hair.
... When HCC is analyzed, researchers make the assumption that the hair growth rate is approximately 1 cm per month. There seems to be a difference in hair growth parameters between African and Caucasian hair; African hair density is lower, and hair growth rate is slower compared to Caucasian hair [37]. Taking this difference into consideration, including subjects of different ethnicities may have affected the results [38]. ...
Childhood obesity has been linked to physical and psychological comorbidities that can be carried into adulthood. A bidirectional link between body weight and the stress system appears to exist, as cortisol may affect the regulation of appetite, while adiposity can affect cortisol secretion. Among the biological tissues used to evaluate cortisol concentrations, scalp hair can provide retrospective measures. The aim of this systematic review was to investigate the difference in hair cortisol concentrations between obese and non-obese minors ≤ 19 years of age. Children and adolescents with genetic, somatic or psychiatric comorbidities were excluded. The work was conducted following the PRISMA guidelines, using prespecified search terms in the Pubmed database. The initial search yielded 56 studies, while the last step of the screening procedure concluded in 9 observational studies. Among them, the results could be characterized as inconclusive. Five of them demonstrated significantly higher hair cortisol concentrations in obese children and adolescents than normal weight subjects. On the contrary, the remaining four found no statistically significant differences in hair cortisol concentrations between obese and non-obese subjects. Different methodologies applied, and confounding factors could explain the inconsistency in the findings. Further research is needed to provide more solid results.
... Careful interpretation is required when measuring hair cortisol concentration, because several confounding factors may intervene, such as radiation exposure [59], extensive washing and brushing [52,60], and chemical treatments, such as shampoos and dyes [61,62]. However, natural hair color does not seem to influence hair cortisol concentration [48,52]. ...
Cortisol is the end product of the hypothalamic-pituitary-adrenal (HPA) axis, and its production is increased mainly in stressful situations or in chronic disorders accompanied by stress enhancement. Altered cortisol concentrations have been reported in a number of neuropsychiatric diseases and sleep disorders. Cortisol concentrations have been measured using several methods, and in several matrixes, such as blood, saliva, and urine. However, lately, hair cortisol, for several reasons, has emerged as a promising biomarker of long-term retrospective HPA activation. Several experimental approaches for cortisol measurement with the corresponding concentration reference ranges and a summary of findings from scientific literature on this field are presented. There is evidence of a close relationship between HPA functional alteration and the development of neuropsychiatric disorders. Sleep disorders are the most common manifestation in several neuropsychiatric conditions, and have also been associated to cortisol alterations in both adults and children. Many studies indicate that hair cortisol constitutes a valuable tool for further contributing to existing data on salivary, plasma, or urinary cortisol concentrations in patients with sleep disorders.
... Assay of hair cortisol concentration (HCC) provides a measure of HPA function. Circulating cortisol is deposited from follicular capillaries, sweat glands and sebaceous glands into all layers of the growing hair shaft (Cook et al., 1964;Russell et al., 2012;Kapoor et al., 2018), which lengthens by approximately 1 cm per month (with some ethnic variation), allowing determination of average HCC over a specific period (Schütz et al., 1993;Loussouarn et al., 2001). HCC ranges between 5 and 91 pg/mg (mean 18 pg/mg), and is not affected by hair colour or sex hormones (Raul et al., 2004), hairdressing treatments or light exposure (Kristensen et al., 2017). ...
Background
Hair cortisol concentration (HCC) can be used to periodically assess hypothalamic–pituitary–adrenal (HPA) axis function, and appears correlated with prolonged exposure to stress.
Methods
Serial assessment (at Baseline, Week 6 and Week 12) of participants ( n = 35) with anxiety disorders by psychopathological rating scales, with assays of HCC and levels of peripheral anti- and pro-inflammatory cytokines. Patients underwent antidepressant treatment for an initial 6 weeks, followed by cyclo-oxygenase inhibitor-2 (COX-2) inhibitor (celecoxib) augmentation or ‘treatment as usual’ for a further 6 weeks.
Results
At Baseline ( n = 35), HCC was elevated in patients with single-episode but not recurrent-episode anxiety disorders, mean IL-12p70 levels were low, and mean TNF-α levels were elevated. Following 6 weeks of antidepressant treatment ( n = 33), mean HCC was within the normal range but mean IL-2 level was low. Celecoxib augmentation ( n = 18) was associated with a reduction in anxiety symptoms and normalisation of mean IL-2 levels.
Limitations
Small sample size. Not all participants were assessed at all time points.
Conclusion
Serial assessment of HCC is practicable in patients with anxiety disorders. These preliminary findings warrant further investigation in larger samples.
... Recently, hair cortisol concentration (HCC) has been considered one biomarker of long-term stress exposure. Due to the fact that hair grows approximately 1 cm/month [12,13], this biomarker can reflect one-month exposure to cortisol for each centimeter of hair collected from the scalp (i.e., 3 cm = 3 months of cortisol exposure). To date there is no consensus regarding the relationship between HCC and cognitive processes. ...
Successful aging depends upon several internal and external factors that influence the overall aging process. Objective and subjective socioeconomic status emerge as potential psychosocial factors in the ethiopathophysiology of aging-related disorders. Presumably, low socioeconomic status can act as a psychosocial stressor that can affect humans' physiology via psychoneuroendocrine mechanisms, that may, in turn, affect the brain physiology. In resting-state electroencephalography (EEG), excess theta and delta activity has been related to cognitive decline and dementia. The main aim of this study was to analyze the effect of objective and subjective socioeconomic status (SES) on cognition and brain electrical activity through EEG measures. The present research constitutes a cross-sectional study with thirty healthy older adults (61-82 years old) separated into two clusters: high socioeconomic (HS) and low socioeconomic (LS) status; they were evaluated and compared in cognitive terms using the Wechsler Adult Intelligence Scale (WAIS-IV). An EEG at rest was recorded to measure brain activity and, as an indicator of long-term stress exposure, hair cortisol concentrations (HCC) were measured. Our results show that lower SES is related to a worse performance in working memory tasks (p = 0.009), higher delta (p = 0.002) and theta power (p = 0.039), and lower alpha activity (p = 0.028). However, it seems that SES does not significantly affect HCC in this population of healthy older adults. The effects of SES on long-term cortisol exposure, brain electrical activity, and cognitive functions in healthy older people emphasize the role of psychosocial factors in aging from an integrative perspective that will allow us to implement better prevention programs to target cognitive decline in adults.
... An approximately 1.5-2 cm length of hair close to the skin, and roughly the area of a pencil eraser, was collected from the posterior vertex region consistent with typical collection protocols [13]. An average hair growth of 0.8 cm per month was assumed as hair of persons of African descent is estimated to grow slightly slower than the average 1 cm/month among Whites [31,32]. Thus the hair samples represent approximately 3 months of accumulated cortisol exposure. ...
This pilot study investigates the correlation between psychological stress and antiretroviral therapy (ART) adherence and plasma HIV RNA (viral load) as mediated by psychological flexibility among Black men in the south. Data were collected from 48 HIV-positive, low income Black men. Results indicate a strong positive correlation between perceived stress and psychological inflexibility (adjusted for age and income rs = 0.67; p < 0.001), a negative correlation between psychological inflexibility and ART adherence (adjusted rs = - 0.32; p = 0.03), a negative correlation between perceived stress and ART adherence (adjusted rs = - 0.45; p = 0.006), and a negative correlation between ART adherence and viral load (adjusted rs = - 0.37; p = 0.04). Our findings suggest stress decreases adherence to ART and viral suppression among Black men living with HIV. However, psychological flexibility did not mediate the relationship between stress and treatment adherence. Hair cortisol concentrations were high (mean of 34.2 pg/mg), but uncorrelated with adherence.
... It is among the few studies assessing HCC and its association with PTSD symptoms in war-affected populations, and to our knowledge the first to directly compare cortisol levels of different displaced groups, thereby enabling us to shed light on the effects of ongoing stress on HPA axis alterations. Moreover, our samples were culturally and ethnically less diverse than samples in previous studies, which minimizes the risk of cultural biases, e.g., eating habits or differences in hair growth between ethnic groups (Loussouarn, 2001). ...
The study of physiology in response to war and forced displacement can yield insight into the origin of stress-related mental health disorders. Previous studies found alterations in hair cortisol concentrations (HCC) in refugees. However, the direction of this alteration in HCC, as well as the association between HCC and psychological stress, remain unclear. Mixed findings can potentially be explained by the lack of contextual factors that have been taken into account. In this explorative study, we investigated HCCs in three female refugee samples (N = 89) in different contexts. Samples were i) asylum seekers from Syria, who sought protection in Germany two years ago (n = 37), ii) internally displaced persons (IDPs), who fled a genocide and lived in conditions of onging insecurity in Iraq (n = 14), and iii) Kurdish immigrants and former asylum seekers, who resettled to Germany 18 years ago and were used as reference group (n = 38). HCC was assessed in the scalp-nearest 6 cm of hair (2*3 cm segments). Data on mental and physical health, exposure to traumatic events, and time between immigration and HCC assessments were collected. Syrian asylum seekers had lower HCC than immigrant controls (η2 = .06). PTSD symptoms and perceived stress were associated with elevated cortisol levels in IDPs (r = .66 and r = .56), while time since immigration was associated with cortisol levels only in immigrant controls (r = .38). We discuss our findings with regard to the importance of contextual factors, particularly time since displacement and on-going insecurity, when studying physiological reactions in refugees.
... A small amount of hair (roughly the diameter of a pencil eraser and estimated to be at least 25 mg) was cut by the study nurse from the posterior vertex region close to the scalp. Typically, hair is estimated to grow 1 cm/month (Stalder et al., 2017); however, slower hair growth rate has been observed for persons of African descent (at an average rate of 0.80 cm/month) (Loussouarn, 2001). We therefore attempted to collect at least 1.6 cm of hair to estimate cortisol accumulation over the previous two months. ...
Dysregulation of the stress response can occur early in life and may be affected by nutrition. Our objective was to evaluate the long-term effect of nutritional supplementation during gestation and early childhood on child cortisol and buccal telomere length (a marker of cellular aging) at 4-6 years of age. We conducted a follow-up study of children born to women who participated in a nutritional supplementation trial in Ghana. In one group, a lipid-based nutrient supplement (LNS) was provided to women during gestation and the first 6 months postpartum and to their infants from age 6 to 18 months. The control groups received either iron and folic acid (IFA) during gestation or multiple micronutrients during gestation and the first 6 months postpartum, with no infant supplementation. At age 4-6 years, we measured hair cortisol, buccal telomere length, and salivary cortisol before and after a stressor. Salivary cortisol was available for 364 children across all three trial arms and hair cortisol and telomere length were available for a subset of children (n = 275 and 278, respectively) from the LNS and IFA groups. Telomere length, salivary cortisol, and hair cortisol did not differ by supplementation group. Overall, these findings suggest that nutritional supplementation given during gestation and early childhood does not have an effect on child stress response or chronic stress in children at 4-6 years. Clinicaltrials.gov registration: NCT00970866.
LAY SUMMARY: This study addressed a research gap about whether improved nutrition during pregnancy and early childhood impacts telomere length and cortisol in preschool children. There was no difference in child telomere length or cortisol between two trial arms of a nutritional supplementation trial that began during pregnancy. The research outcomes indicate lipid-based nutrient supplements, a relatively new form of supplementation, do not have an effect on markers of stress or cellular aging measured in later childhood.
... WIC's hair strand, measuring~5 in. long, represents approximately the last year of her life (Loussouarn, 2001); 12 incremental samples taken along the hair strand record diet variability on the order of~1 month per sample. ...
In 2011, the mummified body of a Black adult female was discovered in a mid'19th c. Fisk iron coffin buried in Queens, New York City. Archival research points to the identity of the woman as Martha Peterson, a domestic worker who lived in the home of William Raymond, the business partner and neighbor of Almond Fisk, the coffin inventor and manufacturer. Here we apply biogeochemical methods to provide information about the Woman in the Iron Coffin's (WIC) residence, diet and health to complement the biological profile and test the archival‐based interpretation of identity. We conducted stable isotopic (δ13C, δ15N, δ18O, 87Sr/86Sr, 206Pb/207Pb) and elemental (As, Sr, Pb) concentration analyses of a second premolar and one strand of hair to characterize her lifeways during middle childhood and near the time of death. Compared to established δ18O and 87Sr/86Sr isoscapes of the US and 206Pb/207Pb values of regional coal and ore, we interpret WIC's geographic location during the time of tooth formation as local to the New York region. WIC's δ13C and δ15N values indicate a mixed diet similar to contemporaneous peoples from other Mid‐Atlantic States. Pb concentrations are potentially indicative of acute Pb‐caused health problems in a ~1‐year period during middle childhood. Our biogeochemical results bolster archival‐based interpretations of WIC's identity as a member of the Peterson's, a local free Black family, and provides a glimpse into the life of a Black woman in 19th c. New York City.
... In addition to variables measured, hairs were also described qualitatively based on previously published features. [11,14,15,17] These included: the hair pigment or color, the hair root shape/type, hair texture as compared to hairs studied by other scientists, and frequency of ovoid bodies. The descriptions obtained for each hair strand were tabulated according to the sex of the participant and the region of the body where it was taken from. ...
Context
Relatively scanty literature on autochthonic African Negroid hair morphology provokes research interest for anthropological, forensic, and cosmetic purposes.
Aims
This study aimed to contribute basic morphological information on Ghanaian African hairs.
Settings and Design
The study was done in selected second-cycle schools in Accra, Ghana, using convenient sampling.
Subjects and Methods
Hairs were obtained by pluck method, from 30 males and 30 females aged 15–20 years. Ghanaian African autochthony was established if individuals had two generations of indigenous Ghanaian parentage. Scalp, eyebrow, axilla, and pubic hairs were image captured using a digital light microscope eyepiece connected to a computer. Diameters of hair strands were measured; types of the medulla and the form and shape of the hair roots were studied.
Statistical Analysis Used
ANOVA test (SPSS Version 17.0) was used to compare the means of quantitative hair features among the sexes and the four regions of the body studied.
Results
Pubic hair shaft was thickest (respective male and female diameters were 100.21 μm, 88.40 μm) and eyebrow hair was thinnest (53.97 and 46.69-μm diameters in males and females, respectively). Axillary and scalp hairs were the closest in diameters with 76.21 and 72.02 μm, respectively, in males and 73.07 and 71.15 μm, respectively, in females. Continuous type medulla was predominant in all hairs, with a trend of percentage occurrence in descending order from the pubic, axilla, eyebrow, and scalp in both sexes.
Conclusions
Bodily regional differences in diameter of hair shaft and medullary presence were affirmed.
... To date, the minimum length of hair reported in the hair cortisol concentration literature has been 1 cm of hair taken from the scalp, indexing an approximate 1-month retrospective period (Kirschbaum et al., 2009). There are individual variations in hair growth rate (LeBeau, Montgomery, & Brewer, 2011), seasonal effects (Randall & Ebling, 1991), and demographic differences (Loussouarn, 2001) to be considered. ...
Much of the existing research on biological mechanisms underlying the stress experience has focused largely on moment‐to‐moment stress, rather than on chronic stress, an arguably more powerful predictor of long‐term outcomes. Recent methodological innovations have paved the way for new lines of research on chronic stress, with promising implications for developmental researchers and for those who study health and adversity. In particular, there are increasing studies that have focused on chronic stress assessments by relying on cortisol derived from hair and nails as a biomarker for chronic stress. In this paper, we provide an overview of their use, describe how hair and nail cortisol ought to be conceptualized differently across the lifespan, how developmental factors may impact its interpretation, and the circumstances under which its use may be more methodologically sensible. The purpose of this review is to provoke further discussion and encourage careful research designs that utilize hair and nail cortisol for understanding the effects of chronic stress exposure from the early developmental period, across adverse contexts, and in association with psychological and physical health outcomes.
... There may be unmeasured variables that influenced the validity of the hair cortisol measure (e.g., activity level, method of hair preparation) (Gerber et al., 2013;Slominski et al., 2015). Relatedly, hair growth profiles may have varied across participants, influencing the accuracy of the timing of the cortisol assessment, particularly between individuals from different racial/ethnic backgrounds (Loussouarn, 2001;Loussouarn et al., 2005). Creating a latent variable for hair cortisol using measures across trimesters and controlling for race/ethnicity in the analyses may have mitigated any such effects. ...
Newborn telomere length is a potential biomarker of the effects of maternal-fetal processes on offspring long-term health. A number of maternal psychosocial and environmental factors in pregnancy (e.g., stress, health, socioeconomic status) have been associated with shortened telomere length at birth. The physiological mechanisms responsible for potential effects of maternal factors on newborn telomere length have yet to be identified. Indirect evidence suggests that disruptions in maternal hypothalamic-pituitary-adrenal (HPA) axis functioning in pregnancy may be involved. Studies are needed that test whether maternal HPA axis functioning in pregnancy is associated with newborn telomere length. This study examined whether maternal HPA axis functioning across pregnancy, reflected in hair cortisol collected within one week after delivery, predicted newborn telomere length assessed from leukocyte cord blood collected at birth among 93 sociodemographically diverse mother-infant dyads. We further tested whether associations between maternal hair cortisol and newborn telomere length differed by infant sex, given documented sex differences in prenatal environmental exposure effects on offspring health, patterns of cortisol exposure during gestation, and telomere biology across the lifespan. In a multi-group structural equation modeling analysis that accounted for cortisol exposures across trimesters, maternal cortisol levels in pregnancy were not associated with newborn telomere length in the sample as a whole. However, significant sex differences emerged, with a significant positive association among females and a lack of a significant association among males. In addition, analyses revealed that cortisol levels were higher across trimesters among mothers of male infants than mothers of female infants. The results suggest that functioning of the maternal HPA axis in pregnancy may differ by fetal sex and have sex-specific effects on newborn telomere biology. These findings have implications for understanding the mechanisms by which maternal psychosocial and environmental exposures influence newborn telomere length and for elucidating mechanisms contributing to sex disparities in health.
... Thus the 3 cm length of hair cortisol measured represents cortisol levels of approximately 3 months before the study. One of the limitations of hair cortisol measurement in general is variation in the growth rate of hair in different subjects as this decrease with age and some diseases such as hypothyroidism or change in cortisol levels due to the local metabolism of hair [56]. Comparison between different immunoassay techniques (ELISA, CLIA, ECLIA, and LC/MS) to measure hair cortisol levels is recommended. ...
Purpose
Hypothyroidism is associated with an increase in serum cortisol level while the long-term activity of hypothalamic-pituitary-adrenal (HPA) axis in hypothyroid, and subclinical hypothyroid (SCH) subjects has not been studied. This study aimed to assess the hair cortisol levels as a long-term activity of HPA axis in hypothyroid, SCH and a group of healthy adult subjects. Also, it aimed to examine the correlation of hair cortisol levels with hypothalamic-pituitary-thyroid (HPT) axis and anthropometric measures.
Methods
We prospectively evaluated a group of normal, SCH and hypothyroid subjects. Serum TSH, FT4, and FT3 were measured as a component of the HPT axis. Hair samples were collected, prepared, followed by extraction of hair cortisol and measurement in pg/mg of hair. Hair cortisol levels were compared in normal, SCH and hypothyroid groups and correlated with HPT axis and anthropometric data.
Results
A total of 65 healthy volunteers were analyzed, and the mean hair cortisol level was reported to be 17.38 pg/mg of hair. Hair cortisol level was slightly higher in the SCH subjects, 18.19 pg/mg of hair; however the difference was not significant. Compared to the euthyroid subject, a significantly higher hair cortisol level was recorded in the hypothyroid subjects, 24.17 pg/mg hair, p < .05. Hair cortisol was significantly and positively associated with each of the serum TSH, age, weight and BMI (p < .05).
Conclusions
Overt hypothyroidism but not SCH is significantly associated with higher hair cortisol levels compared to normal subjects, and a significant relation between hair cortisol with HPT axis was found. Also, weight and BMI were positively correlated with hair cortisol level.
... We used 1 cm of the segments closest to the scalp for cortisol extraction. Considering the hair growth rate of Africans (0.74 cm/month) [42], the hair segment length of 1 cm roughly signifies 1 month of growththe time span assessed by the PSS-I. For cortisol determination, 5-10 mg of whole, nonpulverised hair was incubated in 1800 ml methanol for 18 h at 45°C. ...
Background:
Anecdotal evidence suggests the frequently traumatic nature of female genital mutilation (FGM). At present, systematic research on the psychological sequelae of this tradition has remained limited. The study provides preliminary, high-quality psychodiagnostic data on potential psychopathological consequences of FGM, with a focus on posttraumatic stress disorder (PTSD), shutdown dissociation and other stress-related variables.
Methods:
We investigated a convenience sample of N = 167 women, supported by the women's affairs headquarters in Jijiga (capital of the Ethiopian Somali Region) and a local Ethiopian non-governmental organization. Our main outcome measures were PTSD (PSS-I) and shutdown dissociation (ShuD). We also assessed depression and anxiety (HSCL-25), major depression, substance abuse and dependence, suicidality and psychotic disorders (M.I.N.I.; sub-scales A., B., K., and L.). In addition, we collected hair samples to assess hair cortisol concentrations (HCC) as a neuroendocrinological measure.
Results:
The majority of women endured FGM (FGM I: 36%, FGM II/III: 52%) and, regardless of the level of the physical invasiveness, almost all women reported having felt intense fear and/or helplessness. FGM II/III, the more invasive form, was associated with a greater vulnerability to PTSD symptoms (p < .001) and shutdown dissociation (p < .001). Symptoms of depression (p < .05) and anxiety (p < .01) were also elevated. Random forest regression with conditional inference trees revealed evidence of an alteration of the cortisol levels in relation to the age when FGM was experienced (< 1 year) and the invasiveness of the procedure.
Conclusion:
More extensive forms of FGM are associated with more severe psychopathological symptoms - particularly with an increased vulnerability to PTSD. Higher hair cortisol levels in women who experienced FGM before their first year of age or had more severe forms of FGM indicate long-term neuroendocrinological consequences of FGM and trauma in general on the stress system.
... Investigators should not convey judgment regarding hair hygiene, such as the frequency of hair washings, because some African Americans tend to have dry hair as compared to non-Hispanic whites 13 . African American hair grows slower, at a mean rate of 256 µm/day -1 as compared to non-Hispanic whites (M = 396 µm/day -1 , SD = 55 µm/day -1 ) 14 . Participants may also wear hairstyles such as weaves/sew-in hair, box braids, and kinky twists or crochet braids. ...
The hormone cortisol is typically assessed in saliva, serum, or urine samples. More recently, cortisol has been successfully extracted from hair, including humans. The advantage of hair cortisol concentration is that it reflects a retrospective representation of hypothalamic-pituitary-adrenal (HPA) axis function over time, much like hemoglobin A1C represents glycemic control. However, obtaining hair samples can be challenging, due to the cultural beliefs and hair care practices of minority participants. For example, African Americans may be reluctant to provide samples. Additionally, few researchers are trained to collect hair samples from African Americans. The purpose of this paper is to present a culturally informed protocol to help researchers obtain hair samples from African Americans. To illustrate the representative results of this protocol implementation, de-identified data from African Americans that participated in a community-based study on chronic stress are provided. Hair practice preferences are assessed. The participants are made comfortable by showing pictures of hair samples prior to cutting their hair. The single strain twist and gently pull method is used to collect approximately 30-50 strands of hair from the posterior vertex region of the scalp. This protocol will significantly improve collection of hair samples from African Americans. © 2018, Journal of Visualized Experiments. All rights reserved.
... Hair growth rates may have varied across participants, influencing the accuracy of the timing of the cortisol assessment. Notably, studies suggest small individual differences in hair growth rates, including between individuals from different racial/ethnic backgrounds (Loussouarn, 2001;Loussouarn, El Rawadi, & Genain, 2005). Because hair was collected postdelivery, delivery experiences may have affected cortisol levels. ...
Little research has examined the impact of maternal lifetime trauma exposure on infant temperament. We examined associations between maternal trauma history and infant negative affectivity and modification by prenatal cortisol exposure in a sociodemographically diverse sample of mother-infant dyads. During pregnancy, mothers completed measures of lifetime trauma exposure and current stressors. Third-trimester cortisol output was assessed from maternal hair. When infants were 6 months old, mothers completed the Infant Behavior Questionnaire-Revised. In analyses that controlled for infant sex and maternal age, education, race/ethnicity, and stress during pregnancy, greater maternal trauma exposure was associated with increased infant distress to limitations and sadness. Higher and lower prenatal cortisol exposure modified the magnitude and direction of association between maternal trauma history and infant rate of recovery from arousal. The association between maternal trauma history and infant distress to limitations was somewhat stronger among infants exposed to higher levels of prenatal cortisol. The analyses suggested that maternal lifetime trauma exposure is associated with several domains of infant negative affectivity independently of maternal stress exposures during pregnancy and that some of these associations may be modified by prenatal cortisol exposure. The findings have implications for understanding the intergenerational impact of trauma exposure on child developmental outcomes.
... Signaling during hair follicle cycling relies on some key molecules such as Wnt, Bmp, Shh, and Notch [83,84]. However, regardless of these processes common to all hair follicles, normal biologic variations of hair characteristics occur, related to age, gender, race, and ethnicity [85][86][87], even within a single phenotypic group [88,89]. Unfortunately, there is no genetic test to control for this possible confounder. ...
Human hair is a natural fiber with keratin and keratin-related proteins as a main component. Externally, hair is a thin, pliable tube of dead, fully keratinized epithelial cells, while inside the skin, it is part of a single living hair follicle. In addition to a large amount of protein, hair also contains low levels of lipids and pigments. The hair also has its own ecological balance system. Although the lipid content in hair is much lower than the protein content, it plays an important role in hair and influences hair texture to some extent. For example, prevent hair breakage and thinning; To act as a barrier to moisture loss; and improve the gloss, elasticity and tensile strength of the hair stem. Environment, hair dressing and daily care can all cause hair damage to varying degrees. Factors such as ultraviolet light and chemicals can make hair dry, rough, dull, stiff and brittle by destroying the proteins, pigment sand lipid sin the hair. In this paper, the composition, classification and influencing factors of hair were reviewed. The composition and function of lipids in hair were investigated emphatically. It aims to improve people's understanding of the physical and chemical properties and structure of hair. It provides reference value for the research and development of hair cosmetics for different hair states and washing purposes. The function of hair lipids on hair is not accurate. In addition, there is still some controversy on the existing role of hair lipids, which needs further research.
Males in the Sudanese population are known to utilise a smokeless tobacco product (Toombak) that is placed in the oral cavity and replaced several times a day. Toombak has been shown to harm human health and is highly addictive. The effect on body cortisol response over a retrospective period in users of this product has not been previously explored. In addition, the psycho-dependency level distributed amongst users of Toombak has also not been analysed to date. In this study, 37 male subjects, age 18-45 years were recruited, of which 18 were non-users of Toombak and 19 were Toombak users. One hair sample was collected from each user and non-user of Toombak. Each hair sample (n=37) was placed in a pre-prepared long piece of foil with two marked labels on either side: 'scalp-side' and 'distant-side'. Cortisol was extracted by mincing 10 mg of 'scalp-side' hair, not exceeding 3cm, with methanol addition, incubation, and sonication. Cortisol was measured using the enzyme-linked immunosorbent assay kit (Enzo Life Sciences, UK). The amount of hair cortisol in the samples was determined using spectrophotometry at wavelength 405nm measured in pg/ml and visualised with a four parametric logistic curve. Toombak users were further asked to complete the Fagerstrom Test for Nicotine Dependence-Smokeless Tobacco questionnaire (FTND-ST) comprising of six questions. Scores of > 5 indicated a significant dependence, while a score of <4 marked low to moderate dependence. The mean concentration of hair cortisol in Toombak users (9.7 pg/ml) was significantly lower (p=0.023) compared to non-users (19.4 pg/ml), with total concentrations ranging from 2.1- 55.6 pg/ml. FTND - ST scores ranged from 4-9, with 85% of Toombak users reflecting high levels of psycho-dependency (score>5) and nicotine tolerance. Cortisol body release in Sudanese smokeless tobacco users was found to be significantly altered. While low cortisol levels do lead to anxiolytic effects, long-term, this can allow for an increased susceptibility to low cortisol associated diseases.
Aims: To determine if glycated protein found in scalp hair can predict blood glucose control as characterised by HbA1c. Also, to investigate cosmetic hair treatments' effect and hair sample mass's effect on the assay.
Materials and Methods: 192 participants were included in this study. Anthropometrics, medical history and about 50 strands of hair, 4 cm long, proximal to the scalp, were collected. The concentration of fructosamine in hair was determined using the Thiobarbituric Acid (TBA) method with a fructose calibration curve. The strength of the correlation between HbA1c and fructosamine for hair samples with and without hair treatments was assessed using Pearson's R.
Results: For the samples with no reported hair treatments, there was a statistically positive association between HbA1c and fructosamine when the sample mass ranged between 40mg to 120 mg. A high positive association, r(28) = 0.647, p = <0.001 was observed when hair samples greater than 70mg were used.
Conclusions: Hair glycation can be a robust, non-invasive indicator of blood glucose control in optimum settings. However, sample collection limitations, lengthy assays, and the influence of cosmetic treatments limit its usefulness as a screening tool for diabetes.
Context:
Hair loss is a common complaint among Indian women. For female pattern hair loss (FPHL), diagnosis is primarily clinical. In the early stages, it can be confused with other conditions. Histopathology is the diagnostic method of choice but requires multiple biopsies and can be disfiguring. Trichoscopy is an alternative noninvasive, rapid tool.
Aim:
The aim of this study is to study the hair density and hair diameter variance in relation with severity grading of FPHL.
Settings and design:
Cross-sectional study.
Materials and methods:
Ninety women aged 18 years and above were included in this cross-sectional study conducted at the dermatology department of Bangalore Medical College and Research Institute. Trichoscopic examination was done with a videodermoscope (Firefly DE300) at 20 and 70-fold magnification. Only those patients who met the trichoscopic diagnostic criteria for FPHL were included.
Statistical analysis used:
Descriptive statistics, ANOVA, and Spearman's correlation test for fitness of good, using Microsoft Excel data analysis tools.
Results:
Increase in disease severity from grade one to grade three positively correlated with a decrease in hair density over the frontal scalp (P < 0.001) and the occipital scalp (P < 0.001), decrease in average hair shaft diameter over both frontal and occipital scalp (P < 0.001).
Conclusion:
Trichoscopic tools, particularly hair density and hair diameter variance over both frontal and occipital scalp can be useful to help determine FPHL disease severity and its progression.
Chronic stress is both theoretically and methodologically challenging to operationalize through biomarkers. Yet minimally invasive, field‐friendly biomarkers of chronic stress are valuable in research linking biology and culture, seeking to understand differential patterns of human development across ecological contexts, and exploring the evolution of human sociality. For human biologists, a central question in measurement and interpretation of biomarkers is how stress‐responsive physiological systems are regulated across diverse human ecologies. This article aims to describe a conditional toolkit for human biologists interested in the study of chronic stress, highlighting a mix of longstanding and novel biomarkers, with special focus on hair/fingernail cortisol, latent herpesvirus antibodies, allostatic load indices, and serial/ambulatory data collection approaches. Future trends in chronic stress biomarker research, including epigenetic approaches, are briefly considered. This overview considers: (1) challenges in separating a distinctly psychosocial dimension of chronic stress from adversity more broadly; (2) essential characteristics of human ecology that shape interpretation; (3) retrospective vs. longitudinal sampling; (4) the role of age, developmental effects, and local biologies; (5) different timescales of chronicity; and (6) the role of culture.
Antenatal stress has been associated with adverse birth outcomes such as fetal growth restriction, low birth weight, and preterm birth. Understanding key determinants of stress in a vulnerable pregnant population has the potential of informing development of targeted cost-effective interventions to mitigate against these adverse birth outcomes. We conducted a secondary analysis of data from 150 pregnant women attending antenatal care services at a rural referral hospital in Kenya. The participants completed a sociodemographic and clinical questionnaire, the Cohen’s Perceived Stress Scale (PSS) and gave a hair sample for cortisol and cortisone analysis. The association between selected sociodemographic predictors (age, parity, marital status, maternal education, household income, polygyny, and intimate partner violence) and outcomes (hair cortisol, hair cortisone, and PSS score) was examined using univariate, bivariate and multivariate models. We found a negative association between PSS scores and household income (β = −2.40, p = 0.016, 95% CI = −4.36, −0.45). There was a positive association of the ratio of hair cortisone to cortisol with Adolescent age group (β = 0.64, p = 0.031, 95% CI = 0.06, 1.22), and a negative association with Cohabitation (β = −1.21, p = 0.009, 95% CI = −2.11, −0.31). We conclude that household income influenced psychological stress in pregnancy. Adolescence and cohabitation may have an influence on biological stress, but the nature of this effect is unclear.
Background
Afro hair breakage is most commonly attributed to grooming practices such as braiding, hair extensions and weaves, both for chemically treated hair and natural Afro hair. These grooming practices are also frequently associated with traction alopecia in clinical studies. However, there is little to no quantitative scientific data on the surface and internal hair fibre damage caused by grooming, including combing, on Afro hair.
Methods
Qualitative and quantitative techniques such as scanning electron microscopy, cuticle cohesion and tensile testing were used to determine the effects of frequent braiding on the integrity of female Afro hair in 15 frequent braiders and 15 occasional braiders (control group) in Johannesburg, South Africa. Frequent braiders were women who braided more than 8 times per year, while occasional braiders typically limit braiding to only twice 2 per year. The severity of traction alopecia was quantified in both groups using the standard Marginal Traction Alopecia Scoring system. Surface damage on naturally curly Afro hair, that was combed but not braided, was assessed as another hairstyle option.
Results
All measurements showed a relationship between surface and internal hair fibre damage and braiding frequency. Frequent braiders had thinner hair, with more cuticle damage as shown by SEM and cuticle cohesion assessments. Their hair fibres were also significantly weaker (p<0.05), as shown by the tensile testing. In addition, they also had higher traction alopecia severity scores. In the combing impact assessment, a linear trend was observed between surface hair fibre damage and the number of combing strokes. Cuticle damage from 480 combing strokes was more severe than that from frequent braiding.
Conclusion
Frequent braiding and combing damage natural Afro hair. Quantification of damage caused by different grooming practices, identifies a need to develop products that could help mitigate specific hair damage associated with grooming practices. The degree of damage and subsequent hair loss could also be minimized by education on best braiding practices to protect the hair fibre and avoid hair follicle miniaturization caused by high traction hairstyles.
Hair is a defining feature of mammals. In other species hair confers important functions that affect survival. Most have been lost or are irrelevant in humans but the role of hair in social and sexual signalling in women and in men survives and thrives. Departures from cultural norms, either physiological or due to pathology, can therefore cause much concern and anxiety. Following an introduction to hair biology, this chapter considers the approach to the diagnosis and management of the patient with hair loss before discussing specific hair disorders. These include the various forms of hair loss due to hair follicle pathology, disturbances in hair cycling and hair shaft dystrophies, and disorders associated with excessive hair growth. The chapter concludes with a discussion of acquired alterations in hair pigmentation.
This chapter focuses on the microscopical examination of hair in the forensic domain. It discusses the relevant biological aspects of hair to provide the necessary background information upon which forensic hair examinations are based. The chapter introduces the methodologies and techniques used by forensic hair examiners. It describes the basic chemistry and basic histology of hairs. Each individual hair progresses through a regular and predictable cycle. This cycle is classically described as having three major phases: anagen, catagen, and telogen. While a variety of methods can be used, forceps and tape lifts are the two most commonly employed techniques for collecting hairs. Most forensic hair cases involve the examination of human hair. Historically, the emphasis has been placed on human hair comparisons. The chapter provides general guidelines for the comparison of hairs. Finally, the interpretation and significance of the results obtained through a microscopical hair examination are considered.
In recent years, numerous scientific facts have been appearing and showing that the quality of the physiological reactions depends not only on gender, age, level of training of the subject, but also on the ethnic characteristics of the organism (Doctor Repalova N.V.(2006, 2007; Russia – Kursk State Medical University. Departmente of normal physiology), Doctor Cecília Amaro de Lolio, from the University of São Paulo, from the department of epidemology of public health faculty, on her work ''Epidemiology of hypertension'' (Universidade de São Paulo, Brazil), doctor . P. F. Ama, J. A. Simoneau, M. R. Boulay, O. Serresse, G. Theriault, J. Roberts and T. Drizd, and C. Bouchard from the American physiology societ, Aghajanian, NA, AI Elfimov, Ermakova NV, Severin, A., Radysh IV, Shastun SA Zheltikov, AA, 1981 - 2006, etc.)
All of the above made an interesting study of the hemodynamic changes under the influence of exercise "great pendulum" counter-clockwise from the set of "Slavic gymnastics" among representatives of various ethnic groups.
Earlier studies (Repalova NV, 2006, 2007) showed that the implementation of exercise "Big pendulum" counter-clockwise ("BM") of a set of "Slavic gymnastics" (SG) leads to a statistically significant increase in blood pressure (BP).
In our study involved 69 volunteers, 30 of whom were Indian, 9 Chineses and 8 of Nigerians and 22 Brazilians aged 18 to 25 years. In the first phase of the experiment all participants were asked to exercise "great pendulum" of a set of "Slavic gymnastics" counter-clockwise for 5 minutes. In the second phase of the experiment were asked to perform the activity "slopes" from a standard set of exercises in about 5 minutes. At all stages of pre-and post exercise blood pressure was measured at Korotkoff method and heart rate (HR).
Analysis of the results showed that changes in hemodynamic parameters in the study group during exercise as "BM" counter-clockwise, and during exercise, "slopes" were not statistically significant. So up to the exercises "BM" initial systolic blood pressure of 111 ± 1,62 mm Hg after exercise - 111 ± 1 mm Hg. of Art. Diastolic blood pressure before the BM was 71 ± 1,55, after - 70 ± 1,38 mm Hg. of Art. Pulse has changed from 73 to 75 ± 1,56 ± 1,59 beats / min. Exercise "slopes" change systolic blood pressure from 113 ± 1,57 mm Hg to 116 ± 2,18 mm Hg, diastolic blood pressure from 71 ± 1,49 mm Hg. of Art. to 73 ± 1,46 mm Hg., the pulse-to 75 ± 1,55 ± 1,84 to 77 beats / min.
Thus, these data suggest a significant difference in hemodynamic changes in people of different ethnic groups under the influence of exercise BM counterclockwise from the complex is the SG.
Purpose:
To provide data for forensic use and provoke ideas to preserve shaft integrity, we studied microstructural alterations of female scalp hair subjected to Ghanaian cultural styling methods. Hence, topographical features of female hairs styled by braiding/weaving, and chemical relaxation sampled from five different scalp regions were assessed and compared with natural (Afro) hair.
Subjects and methods:
Ninety-six indigenous Ghanaian females volunteered 480 hairs, which were analyzed by light microscopy. Hairs were plucked using a pair of cosmetologist's tweezers from frontal, left temporal, right temporal, vertex, and occipital regions of the scalp. Hairs were categorized by their grooming styles as Afro (natural-unstyled), natural-styled (weaved/braided), and chemically relaxed. These were studied according to shaft/medulla dimensions and conventional cuticular scale features, and comparisons were made between styling procedures and scalp regions.
Results:
Chemically styled hair had the widest shaft diameter, but the lowest incidence of continuous medullation. Medullary diameter and index increased from chemically relaxed, natural-styled, to Afro hair. A positive but modest correlation between shaft and medullary diameters existed for Afro (r = 0.320, p = 0.011) and natural-styled hairs (r = 0.235, p = 0.022) but not chemically relaxed hair (r = 0.122, p = 0.2). Scale margins were predominantly smooth in Afro hair, crenate in natural-styled hair, and rippled in chemically relaxed hair. With respect to scalp regions, hair shaft diameter was widest in vertex hair and smallest in right temporal hair in all styling methods.
Conclusion:
Medulla was thickest in Afro hair, which also exhibited a correlation with shaft diameter in conformity with the published data. Chemically relaxed hairs did not exhibit these characteristics, which affirm altered morphology. Research on how chemicals affect these changes should help find antidote. The dimensional variations of hairs from different scalp regions are instructive for both cosmetic and forensic examination of hairs.
Objective:
To examine associations of hair cortisol concentration (HCC) in mid-childhood and change in HCC from mid-childhood to early adolescence (ΔHCC) with early adolescent adiposity and cardiometabolic biomarker measures.
Methods:
In Project Viva, a pre-birth cohort of mothers and children, we measured HCC in 599 white children in mid-childhood and in 426 of these participants in early adolescence. We used multivariable linear regression to examine associations of mid-childhood HCC and ΔHCC with BMI-for-age-and-sex z score, waist circumference, waist-height ratio, dual X-ray absorptiometry total and trunk fat mass, a metabolic risk z score, adiponectin, HOMA-IR, high-density lipoprotein, C-reactive protein, interleukin-6, leptin, and systolic blood pressure.
Results:
Over a mean (SD) follow-up of 5.2 (0.8) years, we did not find associations of mid-childhood HCC with BMI-for-age-and-sex z score (β = 0.00 per 1-interquartile range of HCC, 95% confidence interval [CI], -0.08 to 0.07), waist circumference (β = -0.04 cm, 95% CI, -0.83 to 0.74), metabolic risk z score (β = 0.04, 95% CI, -0.03 to 0.11), or other cardiometabolic measures except for an increase in log-transformed HOMA-IR (β = 0.10, 95% CI, 0.04-0.17). ΔHCC was not associated with any outcome measures.
Conclusions:
We found that mid-childhood HCC was not associated with early adolescent adiposity or cardiometabolic biomarkers except for a slight increase in HOMA-IR.
Background:
Androgenic alopecia is common, chronic dermatologic disorder. A variety of lasers and light sources appear to be safe and effective in the treatment of AGA.
Aims:
To evaluate the efficacy and safety of 1540-nm fractional erbium glass laser in the treatment of AGA.
Patients/methods:
This was an interventional therapeutic study for the treatment of patients with AGA. The patients received 10 sessions with 1540-nm fractional erbium glass laser at 2-week intervals. The assessment of the response was done before and at the end of follow-up period, both objectively (the change in the density of terminal hair and the diameter of the hair shaft) and subjectively (patient satisfaction). Any adverse effects were documented during the study.
Results:
Forty-seven out of 51 patients completed the study. After 5 months of laser treatment, the density of hair and hair thickness was significantly increased in both males and females (P value .001).
Conclusion:
The 1540-nm fractional erbium-glass laser seems to be an effective and safe option for treatment of patients with AGA. The improvement was accomplished in a short period.
This represents one of several sections of "A Bibliography Related to Crime Scene Interpretation with Emphases in Geotaphonomic and Forensic Archaeological Field Techniques, Nineteenth Edition" (The complete bibliography is also included at ResearchGate.net.). This is the most recent edition of a bibliography containing resources for multiple areas of crime scene, and particularly outdoor crime scene, investigations. It replaces the prior edition and contains approximately 10,000 additional citations. As an ongoing project, additional references, as encountered, will be added to future editions.
References in this section, like fingerprints, ballistics, and blood evidence, are most often thought of in traditional criminalistics or police sciences. Some of the references below date to the early days of forensics and criminalistics. This section is included because it represents one of the six areas comprising Geotaphonomy: Stratification, Tool Marks, Bioturbation, Sedimentation, Compression/Depression (foot and shoe prints), and Internal Compaction. In addition to the recovery and interpretation of impression evidence, other trace evidence which might be found on surface and subsurface death scenes are cited. Entomological and botanical evidence also constitute trace items left or taken from crime scenes. Because of the number of works referencing those topics, they are addressed in respective sections in this bibliography. Some citations in this section could also be cross-referenced with those in Taphonomy given their discussion of the detioration, or decomposition of hairs and fibers among victims' remains or contamination of impression evidence through prolonged exposure at crime scenes.
When this compiler first became interested in forensic science, one of the first references he read, and which most influenced subsequent processing of scenes and research, was Crime Investigation by Paul Kirk (1974). In that paper the words of Kirk serve as the foundation for collecting trace evidence at any scene regardless its age or condition:
"Wherever he steps, whatever he touches, whatever he leaves, even unconsciously, will serve as silent witness against him. Not only his fingerprints or his foot prints, but his hair, the fibers from his clothing, the glass he breaks, the tool mark he leaves, the paint he scratches, the blood or semen he deposits or collects. All of these and more bear mute witness against him. This evidence does not forget. It is not confused by the excitement of the moment. It is not absent because human witnesses are. It is factual evidence. Pysical evidence cannot be wrong. It cannot perure itself. It cannot be wholly absent. Only its interpretation can err. Only human failure to fint it, study and understand it, can diminish its value."
The present review will focus on basic principles involved in human hair evaluation using imaging, i.e., photographic and computerized methods. The visibility of hair will depend not only on the resolution power of the optics and charge coupled device (CCD) camera but also on the natural contrast between the object, i.e., hair (with every variation of the fiber components and optical interfaces) and background (including skin as a heterogeneous and variable background and extraneous material).
Background:
Female sex workers (FSWs) are at high risk for gender-based violence (GBV) and HIV infection. This study aimed to identify associations between GBV exposure in the past 12 months and biomarkers of physiologic stress and inflammation that may play a role in increased HIV risk among Kenyan FSWs.
Materials and methods:
Participating women responded to a detailed questionnaire on GBV and mental health. Plasma was collected for assessment of systemic C-reactive protein (CRP) and interleukin-6 (IL-6) levels. Hair proximal to the scalp was collected to measure cortisol concentration. CRP and IL-6 were measured by enzyme-linked immunosorbent assay, and hair cortisol concentration was determined by enzyme immunoassay. Log-transformed biomarker values were compared across GBV exposure categories using Kruskal-Wallis or Wilcoxon rank sum tests. Multivariable linear regression was used to explore associations between recent GBV and hair cortisol concentration.
Results:
Two hundred eighty-three women enrolled, of whom 112 (39.6%) reported physical, sexual, or emotional violence in the past 12 months, 134 (47.3%) reported more remote exposure, and 37 (13.1%) reported no exposure. CRP and IL-6 levels did not differ across groups (p = 0.57 and p = 0.62, respectively). Among 141 women who provided hair, cortisol concentrations were higher among recently exposed women compared to the other two groups combined (p = 0.02). In multivariable regression, recently exposed women had higher hair cortisol levels than remotely exposed or unexposed women (adjusted beta = 0.52, 95% confidence interval 0.02-1.02, p = 0.04).
Conclusions:
While CRP and IL-6 levels did not differ by GBV category, recent GBV was associated with increased hair cortisol concentration. GBV-related increases in cortisol could affect health outcomes and merit study in relation to HIV acquisition risk.
Traumatic exposure is particularly devastating for those who, at a young age, have become combatants or experienced massive adversity after abduction by armed movements. We investigated the impact of traumatic stressors on psychopathology among war-affected young men of Northern Uganda, including former child soldiers. Adaptation to violent environments and coping with trauma-related symptoms often result in an increasing appetite for violence. We analyze implicit attitudes toward violence, assessed by an Implicit Association Test (IAT), among 64 male participants. Implicit attitudes varied as a function of the number of experienced traumatic event types and committed offense types. As the number of traumatic experiences and violence exposure increased, more appetitive aggression was reported, whereas the IAT indicated increasingly negative implicit attitudes toward aggression. The IAT was also the strongest predictor of cortisol levels. Diffusionmodel analysis was the best way to demonstrate IAT validity. Implicit measures revealed the trauma-related changes of cognitive structures.
Hair is predominantly a proteinaceous fiber that originates from hair follicles located within the subcutis and/or dermis of the skin. It is one of the defining features of mammals, serving important functions, such as thermoregulation and endothermy. Among mammals, humans are exceptional in lacking a full covering of body hair. Instead the growth of terminal hairs is limited to specific body regions, such as the scalp, axillae, and groin. Our aim in this chapter is to provide an overview of the anthropology of human scalp hair. We will explore approaches to the study of variation in human scalp hair phenotypes, as well as the genetic and evolutionary basis of this diversity. The biology of human scalp hair, with emphasis on quantitative and qualitative differences among populations, as well as impact on hair grooming practices will also be discussed.
High-quality standardized imaging procedures are essential for objective documentation and accurate evaluation of hair growth and hair loss. As far as photography is concerned, global viewing and analytical image techniques are mandatory for clinical studies and for evaluating hair growth. The development of contrast-enhanced phototrichogram with exogen collection (CE-PTG-EC) resulted from 25 years of continuous step-by-step technological improvement, comparative research and development.
In our hands, CE-PTG-EC has allowed accurate and precise measurements of the scalp and body hair variables; hair density, hair thickness, and linear hair growth rate; together with the exact and meticulous staging of the hair follicle cycle. Transitions from the anagen, catagen, telogen, and exogen phases have been quantified for normal subjects and patients.
In the general dermatological or hair clinic, CE-PTG-EC is applicable in patients complaining of hair shedding because it describes all individual parameters that contribute to maintaining hair volume, each of which may be affected separately or in association with each other.
As experience accumulates in combing global and analytical approaches, we are now at the verge of translating numbers into figures that help as quantitative differential diagnostics with updated limits that separate normal subjects from patients complaining about hair loss!
This chapter explores the nature of changes that hair and nail can undergo in different depositional environments, drawing upon archaeological, forensic and experimental observations. The evidential or research value of hair and nail continues to expand with new biomolecular approaches, many of which exploit the incremental nature of hair and nail growth. Infections caused by dermatophytes and non-dermatophytic infections affecting hair and nail, have been extensively reported within the clinical literature forwhich targeted therapies are recommended. Microbial alteration to hair will change the appearance of the fibre in several ways by either destroying tissue or physically disrupting the layered structure of the fibre, particularly the outer cuticle, which is largely responsible for the optical properties of the fibre. Hair and nails can retain valuable microscopic evidence, including particulates, such as gunshot and explosives residues, and soil that serve as valuable ecological indicators. Recommendations exist for processing hair for this type of evidence at autopsy.
Chemical relaxers are products marketed to straighten the hair and have been principally used by African Americans since the early twentieth century. They contain alkaline agents that break and reform hydrogen and disulfide bonds, leaving hair permanently straightened. Relaxers cause loss of tensile strength and increased fragility of the hair shaft that lead to increased risk of hair breakage and thinning. When used improperly, they can also cause local irritant contact dermatitis and chemical burns to the scalp and hairline that can potentially lead to a scarring alopecia. After interviewing several cosmetology educators in the field and reviewing the literature, we generated a list of ten pearls that all dermatologists should know about relaxers to provide professional guidance to their patients.
The unit area trichogram was defined in the frontal and occipital areas of ten normal men and ten normal women and the results compared with the findings in ten male and fifteen female patients with androgenic alopecia. The epilation technique provided accurate data of normal hair density (higher than previously reported) and the phases of hair growth. The measurement of hair diameter showed that of 7603 hairs, 1241 were less than 40 microns in diameter, of which only 21 were more than 80 mm in length. Variation in the diameter of individual hair fibres was recorded. The number of hairs less than 40 microns diameter per cm2 of scalp was increased in both men and women with androgenic alopecia. It was concluded that the number of hairs greater than 40 microns in diameter per cm2 (meaningful density) reflected most closely the amount of hair usefully contributing to an individual's clinical appearance.
The conditions of normality or abnormality of the hair system are reflected in its morphological parameters, such as hair density, state of cycle, thickness of the hair shaft, rate of growth, and hair color.
“Surgery of the Skin: Procedural Dermatology,” covers the entire range of dermatologic surgical procedures. It was conceived to be used as the core surgical textbook for dermatologic training programs. Dr. Bernstein’s chapter on follicular unit hair transplantation covers a wide range of subjects including the history of follicular unit hair transplantation, evaluating the patient, planning the surgery, setting-up the operating room, and maximizing the cosmetic outcome of the hair restoration. Specific topics include the techniques of Follicular Unit Transplantation including density assessment, single-strip harvesting, follicular unit extraction, anesthetic use, aesthetic design and many other important topics.
Various parameters of hair growth were determined every 28 days for 18 months in 14 healthy Caucasian men aged 18-39 with indoor occupations in Sheffield, U.K. (latitude 53.4 degrees N). In the scalp the proportion of follicles in anagen reached a single peak of over 90% in March, and fell steadily to a trough in September. The number of shed hairs reached a peak around August/September, when least follicles were in anagen. At this time the average loss of hairs was about 60 per day, more than double that during the preceding winter. The rate of growth of the beard was lowest in January and February and increased steadily from March to July to reach a peak about 60% above the winter level. The rate of growth of thigh hair showed a similar pattern though with less pronounced differences. No seasonal fluctuations in finger- or toenail growth were detected.
Clinical investigation and hair plucking performed during trichogram, a traumatic technique for obtaining a hair formula, are the present means of evaluation in patients with alopecia or complaining of loss of hair. These means do not provide quantitative data valuable enough for a possible appreciation of the severity of hair loss, let alone for a reliable evaluation in therapeutical trials. Phototrichogram, a technique proposed by Saitoh (1970), Fiquet and Courtois (1979) and developed by Bouhanna (1982-1983), brings more satisfactory qualitative and quantitative means of studying hair growth and pilar cycles. Its standardisation had yet to be obtained so as to give results comparable from one study to another and reproducible in any given patient. We propose here a standardised optical equipment and particularly recommend a rigid frame allowing a fixed distance from the skin to the lens, and a superimposed glass window with millimetric graduations; the 0.50 square centimeter skin area to be analysed may easily be marked off by an 0.2 mm wide black microtatoo. This personal technical adaptation gives an easily obtainable definition of five quantitative parameters analysing the hair on a given area of the scalp: density of implantation, telogen percentage, growth rate, mean anagen diameter and percentage of fine hair less than 40 mu in diameter. In the normal male adult our measurements gave the following results on the vertex: density 204 +/- 10 hair per square centimeter, telogen percentage 17.8 +/- 2.8 p. 100, growth rate 0.35 +/- 0.03 mm p. day, mean anagen diameter 76 +/- 5 mu, percentage of fine hair 9.2 +/- 1.8 p. 100.(ABSTRACT TRUNCATED AT 250 WORDS)
The hair follicle and shaft in blacks have unique configurations. The occurrence of certain disorders such as hot-comb and traction alopecia, proximal trichorrhexis nodosa, trichonodoses, and pseudofolliculitis predominantly among blacks is related to the morphology as well as methods of caring for black hair. In addition, there are several disorders of unknown etiology such as dissecting cellulitis that also occur primarily in blacks. Familiarity with all of the structural differences that distinguish black hair and the disorders that affect the black patient's hair and scalp will enable dermatologists to provide proper diagnoses, treatment, and counselling for their black patients.
Hair growth from the vertex, temple, mustache, finger, arm and leg of three Japanese men (60, 30, and 21 years of age) was measured by direct observation from October, 1966 to November 1968. Detailed information regarding hair growth cycles in the regions tested is presented.
Three basic hair patterns of the scalp are recognized. These are totopilose, indentato-pilose, and indentato-circulo-pilose. The indentato-pilose has the highest incidence in both white and Negro males, and the totopilose is over four times more common in the Negroes than in the whites. The indentato-pilose has high correlation with the pecto-sterno-infraclavicular chest hair pattern in both groups.
The phototrichogram is a non-invasive technique by which, on the same precise area of the scalp, each individual hair may be identified, and its current growth phase established. This technique was used to study the duration of hair cycles in 10 male subjects, balding and non-balding, by observations at monthly intervals over a period of 8-14 years. The accumulated data served to characterize the effects of ageing in these subjects: a reduction in the duration of hair growth and in the diameter of hair shafts, most evident in the thickest hairs, and a prolongation of the interval separating the loss of a hair in telogen and the emergence of a replacement hair in anagen. These various aspects of ageing of scalp hair contribute to its progressive overall impoverishment. They resemble those observed in the course of male-pattern balding, although their development is less marked.
Male pattern alopecia is the outcome of profound modifications in the duration, succession and frequency of hair cycles. These phenomena were studied by phototrichogram in 10 male subjects, with or without alopecia, over a period of 15 years. Almost 10,000 hair cycles were accounted for, yielding a detailed picture of the alopecia condition: (1) A decrease in the duration of anagen for a certain proportion of hairs, a proportion which increases in size, the more advanced the alopecia; the result of this premature transformation from anagen to telogen is an increase in the rate of hair loss. (2) A parallel decline in hair diameter. (3) Longer latency periods between the fall of a hair and the onset of regrowth, leading to a reduction in the number of hairs present on the scalp surface. The shorter finer hairs are absent more frequently and absent for longer periods and this contributes to the effect of alopecia.
Photographic methods for hair evaluation are frequently proposed as an alternative to more invasive methods (trichogram or biopsy). The reliability in terms of quantitative follow-up of hair growth has not been evaluated properly. We report results of comparative studies of scalp hair evaluation with various photographic methods. Statistically significant findings were a better detection of scalp hairs using the original enlargement x 3 as compared to x 2 (212 vs. 167 hair follicles/cm2) and a more acceptable estimate of linear hair growth rate with 'scalp immersion proxigraphy' (SIP) (0.317 mm/day) as compared with classical phototrichogram pictures where this variable was underestimated by 30% on average (0.27 mm/day). SIP-generated linear hair growth rates were very close to the micrometric method (0.37 mm/day). Therefore SIP x 3 images appear preferable for hair growth monitoring during clinical trials.
Summary Ten men, with or without alopecia, were observed for a period of between 8 and 14 years using phototrichograms on a precisely located zone on the vertex of the scalp. Among the various parameters observed, we chose the percentage of hairs in telogen as the criterion for assessment of hair shedding. Mathematical analysis of the variations in this telogen percentage was carried out for each individual subject and for the whole group, as represented by the population mean (or the ‘average subject’). This analysis demonstrated the existence of overall annual periodicity, manifested by a maximal proportion of telogen hairs at the end of summer and the beginning of autumn. Some subjects also exhibited a periodicity approximately corresponding to two annual peaks. In those subjects with a very low proportion of hairs in telogen, no periodicity was demonstrated.
In another group of subjects, it has been shown that the variations in telogen percentage reflect those observed in hair shedding, assessed in a standardized manner. Periodicity of the telogen percentage, and hence of hair fall, is not independent of climatic factors (sunshine hours), and these must be taken into account when assessing the treatment or prevention of hair loss.
Follicular transplantation is a method of hair restoration surgery that uses hair in its naturally occurring groups, called follicular units. Using the follicular unit exclusively in the transplant, the surgeon can create hair patterns that closely mimic nature.
To focus on various aesthetic aspects of the follicular transplantation procedure including hair distribution, hairline design, and crown restoration. Racial variations that affect the transplant will also be examined.
Follicular transplantation is performed according to techniques detailed in a previous publication (Bernstein et al. Int J Aesthet Rest Surg 1995; 3: 119-32).
Excellent cosmetic results can be achieved when aesthetic decisions are made that allow the surgeon to recreate hair patterns already provided by nature. A case study will be presented.
The small size of follicular implants enables the surgeon great versatility in their placement. Follicular transplantation will ensure a natural looking transplant if used with good aesthetic judgment and careful planning.
African-American hair is unique due to its geometry--a kinky hair shaft with variations in diameter. This complex shaft structure creates the need for specialized grooming products and procedures to ensure that the hair maintains its cosmetic value.
This paper identifies the physiological basis for hair and skin care of African-American children and adults. Culturally specific terms are included to assist readers from other cultures to understand and communicate with African-American clients. In addition to describing various hair styles used by African-Americans, products that can assist with caring for black hair and skin are also discussed. Black and African-American are used interchangeably.
The meager data on normal hair density in humans have been gathered from a predominantly white population. Examination of scalp biopsy specimens from African Americans suggests that hair density in this group may be lower than in whites. This study was performed to quantify any differences between white and African American patients.
A retrospective case series of subjects who had undergone a biopsy of clinically healthy scalp skin. The 4-mm punch biopsy specimens were sectioned, and all follicles contained within the specimens were counted at various levels (suprabulbar, isthmus, and infundibulum) to arrive at the number and type of hairs present.
Outpatient clinic in a tertiary care medical center.
A consecutive sample of 22 African American and 12 white patients with clinically healthy scalp skin specimens that were studied and compared with previously reported data.
Patients' age and total number of follicles, terminal follicles, vellus follicles, terminal anagen hairs, and terminal telogen hairs.
Total hair density (number of follicles per 4-mm punch biopsy specimen) and total number of terminal follicles and terminal anagen hairs were significantly lower in African Americans (P<.001) than in whites and in a previously reported, predominantly white, population.
Hair density in African Americans is significantly lower than that in whites, which must be taken into consideration when evaluating a biopsy specimen from an African American patient. Data previously collected from white patients may not provide adequate guidance when evaluating scalp biopsy specimens from African Americans and could lead to an incorrect diagnosis.
The hair of normal black Africans forms a mat of tightly interwoven hair shafts. The effect of this on the structure of the hair shaft and the response to grooming is unknown.
Our purpose was to use light and scanning electron microscopy (SEM) to examine the structure of Negroid-type hairs and effects of combing in black African volunteers.
Hair samples were collected, by combing, from Africans and compared with those from Caucasian and Asian volunteers. The volunteers had never used chemical treatments. Their hair had not been cut for at least 1 year and grooming had been limited to shampooing, drying, and combing.
More than 2000 hairs in 12 African volunteers were examined by light microscopy. The hairs appear as a tight coiled springlike structure. Many shafts exhibited knots (10%-16% vs 0.15%) and appear broken compared with hair shafts from other ethnic groups. SEM of African hairs showed features consistent with repeated breaks of the shaft. Examination of hairs in situ showed interlocking of hair shafts.
These observations provide an understanding of the physical nature of, and effect of combing on, black African hair.
Phototricho-gram: an entirely automated method of quantification by analysis
- Courtois M G Loussouarn
- Hourseau
Chatenay F, Courtois M, Loussouarn G, Hourseau C. Phototricho-gram: an entirely automated method of quantification by analysis.
Ageing and hair cycle Hair patterns of scalp of white and negro males
- Courtois M G Loussouarn
- C Hourseau
- Grollier
- Jf
Courtois M, Loussouarn G, Hourseau C, Grollier JF. Ageing and hair cycle. Br J Dermatol 1995; 132: 86±93. 18 Sety LR. Hair patterns of scalp of white and negro males. Am J Phys Anthrop 1970; 33: 49±56.
Disorders of Hair Growth: Diagnosis and Treatment
- Wilborn WS
Hair and Hair Diseases
- Pecoraro V
- Astore IPL
Seasonal changes in human hair growth
- Randall VA
- Ebling FJG