Article

Body Mass Index and Breast Size in Women: Same or Different Genes?

October 2010
Twin Research and Human Genetics 13(5):450-4

DOI:10.1375/twin.13.5.450

Source
PubMed

Authors:

The objective of the current study was to investigate the heritability of breast size and the degree to which this heritability is shared with BMI. In a sample of 1010 females twins (mean age 35 years; SD = 2.1; range 28-40), self-report data pertaining to bra cup size and body mass index (BMI) was collected in the context of self-report data and an interview relating to disordered eating respectively. In a sample of 348 complete twin pairs who completed data collection (226 MZ pairs and 122 DZ pairs and 360 incomplete pairs (170 MZ and 190 DZ)), we found that the heritability of bra cup size was 56%. Of this genetic variance, one third is in common with genes influencing body mass index, and two thirds (41% of total variance) is unique to breast size, with some directional evidence of non-additive genetic variation. The implications of these findings with respect to previous research linking breast size with reproductive potential are discussed.

Stereotypical and Actual Associations of Breast Size with Mating-Relevant Traits

Article

Full-text available

Apr 2020
ARCH SEX BEHAV

Breast size varies substantially among women and influences perception of the woman by other people with regard to her attractiveness and other characteristics that are important in social contexts, including mating. The theory of sexual selection predicts that physical criteria of partner selection should be markers of the candidate’s desirable properties, mainly biological quality. Few studies, however, have examined whether breast size really signals biological quality or its components and whether observers accurately interpret these signals. Our first study encompassed 163 young women and aimed to establish actual correlates of breast size. The aim of the second study was to determine preferences and stereotypes related to breast size: 252–265 women and men evaluated female digital figures varying in, among other characteristics, breast size. Breast size (breast circumference minus chest circumference) was negatively associated with body asymmetry and positively associated with infections of the respiratory system, but did not correlate with infections of the digestive system, openness to casual sex, and testosterone and estradiol level. Women and men perceived breasts in a similar way to each other: the bigger the breasts the higher the reproductive efficiency, lactational efficiency, sexual desire, and promiscuity attributed to the woman. Nevertheless, large breasts were not regarded more attractive than average ones, though small breasts were the least attractive. In addition, big-breasted women were perceived as less faithful and less intelligent than women with average or small breasts. We discuss our results from the perspectives of evolutionary psychology, perceptual biases, and social stereotypes.

Resource Security Impacts Men’s Female Breast Size Preferences

Article

Full-text available

Mar 2013
PLOS ONE

It has been suggested human female breast size may act as signal of fat reserves, which in turn indicates access to resources. Based on this perspective, two studies were conducted to test the hypothesis that men experiencing relative resource insecurity should perceive larger breast size as more physically attractive than men experiencing resource security. In Study 1, 266 men from three sites in Malaysia varying in relative socioeconomic status (high to low) rated a series of animated figures varying in breast size for physical attractiveness. Results showed that men from the low socioeconomic context rated larger breasts as more attractive than did men from the medium socioeconomic context, who in turn perceived larger breasts as attractive than men from a high socioeconomic context. Study 2 compared the breast size judgements of 66 hungry versus 58 satiated men within the same environmental context in Britain. Results showed that hungry men rated larger breasts as significantly more attractive than satiated men. Taken together, these studies provide evidence that resource security impacts upon men's attractiveness ratings based on women's breast size.

The evolution of perennially enlarged breasts in women: a critical review and a novel hypothesis

Article

Jul 2021

The possession of permanent, adipose breasts in women is a uniquely human trait that develops during puberty, well in advance of the first pregnancy. The adaptive role and developmental pattern of this breast morphology, unusual among primates, remains an unresolved conundrum. The evolutionary origins of this trait have been the focus of many hypotheses, which variously suggest that breasts are a product of sexual selection or of natural selection due to their putative role in assisting in nursing or as a thermoregulatory organ. Alternative hypotheses assume that permanent breasts are a by‐product of other evolutionary changes. We review and evaluate these hypotheses in the light of recent literature on breast morphology, physiology, phylogeny, ontogeny, sex differences, and genetics in order to highlight their strengths and flaws and to propose a coherent perspective and a new hypothesis on the evolutionary origins of perennially enlarged breasts in women. We propose that breasts appeared as early as Homo ergaster, originally as a by‐product of other coincident evolutionary processes of adaptive significance. These included an increase in subcutaneous fat tissue (SFT) in response to the demands of thermoregulatory and energy storage, and of the ontogenetic development of the evolving brain. An increase in SFT triggered an increase in oestradiol levels (E2). An increase in meat in the diet of early Homo allowed for further hormonal changes, such as greater dehydroepiandrosterone (DHEA/S) synthesis, which were crucial for brain evolution. DHEA/S is also easily converted to E2 in E2‐sensitive body parts, such as breasts and gluteofemoral regions, causing fat accumulation in these regions, enabling the evolution of perennially enlarged breasts. Furthermore, it is also plausible that after enlarged breasts appeared, they were co‐opted for other functions, such as attracting mates and indicating biological condition. Finally, we argue that the multifold adaptive benefits of SFT increase and hormonal changes outweighed the possible costs of perennially enlarged breasts, enabling their further development.

The genetic interplay between body mass index, breast size and breast cancer risk: A Mendelian randomization analysis

Article

Full-text available

Jun 2019
INT J EPIDEMIOL

Background: Evidence linking breast size to breast cancer risk has been inconsistent, and its interpretation is often hampered by confounding factors such as body mass index (BMI). Here, we used linkage disequilibrium score regression and two-sample Mendelian randomization (MR) to examine the genetic associations between BMI, breast size and breast cancer risk. Methods: Summary-level genotype data from 23andMe, Inc (breast size, n = 33 790), the Breast Cancer Association Consortium (breast cancer risk, n = 228 951) and the Genetic Investigation of ANthropometric Traits (BMI, n = 183 507) were used for our analyses. In assessing causal relationships, four complementary MR techniques [inverse variance weighted (IVW), weighted median, weighted mode and MR-Egger regression] were used to test the robustness of the results. Results: The genetic correlation (rg) estimated between BMI and breast size was high (rg = 0.50, P = 3.89x10-43). All MR methods provided consistent evidence that higher genetically predicted BMI was associated with larger breast size [odds ratio (ORIVW): 2.06 (1.80-2.35), P = 1.38x10-26] and lower overall breast cancer risk [ORIVW: 0.81 (0.74-0.89), P = 9.44x10-6]. No evidence of a relationship between genetically predicted breast size and breast cancer risk was found except when using the weighted median and weighted mode methods, and only with oestrogen receptor (ER)-negative risk. There was no evidence of reverse causality in any of the analyses conducted (P > 0.050). Conclusion: Our findings indicate a potential positive causal association between BMI and breast size and a potential negative causal association between BMI and breast cancer risk. We found no clear evidence for a direct relationship between breast size and breast cancer risk.

Assessing the genetic correlations between early growth parameters and bone mineral density: A polygenic risk score analysis

Article

Aug 2018

Objective: The relationships between early growth parameters and bone mineral density (BMD) remain elusive now. In this study, we performed a large scale polygenic risk score (PRS) analysis to evaluate the potential impact of early growth parameters on the variations of BMD. Methods: We used 2286 Caucasian subjects as cohort 1 and 3404 Framingham Heart Study (FHS) subjects as cohort 2 in this study. BMD at ulna & radius, hip and spine were measured using dual energy X-ray absorptiometry. BMD values were adjusted for age, sex, height and weight as covariates. Genome-wide single-nucleotide polymorphism (SNP) genotyping of the 2286 Caucasian subjects was performed using Affymetrix Human SNP Array 6.0. The GWAS datasets of early growth parameters were driven from the Early Growth Genetics Consortium, including birth weight (BW), birth head circumference (BHC), childhood body mass index (CBMI), pubertal height growth related indexes and tanner stage. Polygenic Risk Score (PRSice) and linkage disequilibrium (LD) score regression analysis were conducted to assess the genetic correlation between early growth parameters and BMD. Results: We detected significant genetic correlations in cohort 1, such as total spine BMD vs. CBMI (p value = 1.51 × 10-4, rg = 0.4525), right ulna and radius BMD vs. CBMI (p value = 1.51 × 10-4, rg = 0.4399) and total body BMD vs. tanner stage (p value = 7.00 × 10-4, rg = -0.0721). For cohort 2, significant correlations were observed for total spine BMD vs. height change standard deviation score (SDS) between 8 years and adult (denoted as PGF + PGM) (p value = 3.97 × 10-4, rg = -0.1425), femoral neck BMD vs. the timing of peak height velocity by looking at the height change SDS between age 14 years and adult (denoted as PTF + PTM) (p value = 7.04 × 10-4, rg = -0.2185), and total spine BMD vs. PTF + PTM (p value = 6.86 × 10-4, rg = -0.2180). Conclusion: Our study results suggest that some early growth parameters could affect the variations of BMD.

Determinants of breast size in Asian women

Article

Full-text available

Jan 2018

Breast size as a risk factor of breast cancer has been studied extensively with inconclusive results. Here we examined the associations between breast size and breast cancer risk factors in 24,353 Asian women aged 50 to 64 years old enrolled in a nationwide mammography screening project conducted between October 1994 and February 1997. Information on demographic and reproductive factors was obtained via a questionnaire. Breast size was ascertained as bust line measured at study recruitment and total breast area measured from a mammogram. The average bust line and total breast area was 91.2 cm and 102.3 cm2, respectively. The two breast measurements were moderately correlated (Spearman correlation coefficient = 0.65). Age, BMI, marital and working status were independently associated with bust line and total breast area. In the multivariable analyses, the most pronounced effects were observed for BMI (24.2 cm difference in bust line and 39.4 cm2 in breast area comparing women with BMI ≥30 kg/m2 to BMI <20 kg/m2). Ethnicity was a positive predictor for total breast area, but not bust line.

Large-scale genotyping identifies a new locus at 22q13.2 associated with female breast size

Article

Full-text available

Jul 2013
J MED GENET

Individual differences in breast size are a conspicuous feature of variation in human females and have been associated with fecundity and advantage in selection of mates. To identify common variants that are associated with breast size, we conducted a large-scale genotyping association meta-analysis in 7169 women of European descent across three independent sample collections with digital or screen film mammograms. The samples consisted of the Swedish KARMA, LIBRO-1 and SASBAC studies genotyped on iCOGS, a custom illumina iSelect genotyping array comprising of 211 155 single nucleotide polymorphisms (SNPs) designed for replication and fine mapping of common and rare variants with relevance to breast, ovary and prostate cancer. Breast size of each subject was ascertained by measuring total breast area (mm(2)) on a mammogram. We confirm genome-wide significant associations at 8p11.23 (rs10086016, p=1.3×10(-14)) and report a new locus at 22q13 (rs5995871, p=3.2×10(-8)). The latter region contains the MKL1 gene, which has been shown to impact endogenous oestrogen receptor α transcriptional activity and is recruited on oestradiol sensitive genes. We also replicated previous genome-wide association study findings for breast size at four other loci. A new locus at 22q13 may be associated with female breast size.

The relationship between breast size and anthropometric characteristics

Article

Mar 2012
AM J HUM BIOL

Current clinical selection criteria for mammaplasty use weight-related parameters, and weight loss is recommended as a nonsurgical intervention to reduce breast size. However, research has not firmly established if breast size is related to body size and composition. This study aims to investigate anthropometric characteristics in smaller and larger breasted women and identify predictors of breast mass. A bra fitter determined underband and cup size of 93 A to H cup size women (mean ± standard deviation, age 25.7 ± 5.6 years, height 1.67 ± 0.6 cm, and mass 65.6 ± 11.0 kg). Estimations of breast mass (g) were made, and participants were categorized as smaller (<500 g) or larger (>500 g) breasted. Restricted anthropometric profiles determined body mass, height, body mass index (BMI), waist-to-hip ratio, sum of eight skinfolds, subscapular to triceps skinfold ratio, somatotype, percent body fat, fat and fat-free mass, and suprasternal notch to nipple distance. All variables (excluding height, subscapular to triceps skinfold ratio, and age) were significantly greater in larger breasted women. Body mass-related parameters and suprasternal notch to nipple distance were positively related to breast mass, with BMI and suprasternal notch to nipple distance accounting for half of the variance in breast mass. Smaller and larger breasted women demonstrate differences in anthropometry, with body mass and BMI demonstrating strong relationships to breast mass. Measures of BMI and suprasternal notch to nipple distance enable predictions of breast mass and suggest that weight-related parameters are not appropriate exclusion criteria for mammaplasty.

Look how far we have come: BREAST cancer detection education on the international stage

Article

Full-text available

Jan 2023

The development of screening mammography over 30 years has remarkedly reduced breast cancer–associated mortality by 20%-30% through detection of small cancer lesions at early stages. Yet breast screening programmes may function differently in each nation depending on the incidence rate, national legislation, local health infrastructure and training opportunities including feedback on performance. Mammography has been the frontline breast cancer screening tool for several decades; however, it is estimated that there are 15% to 35% of cancers missed on screening which are owing to perceptual and decision-making errors by radiologists and other readers. Furthermore, mammography screening is not available in all countries and the increased speed in the number of new breast cancer cases among less developed countries exceeds that of the developed world in recent decades. Studies conducted through the BreastScreen Reader Assessment Strategy (BREAST) training tools for breast screening readers have documented benchmarking and significant variation in diagnostic performances in screening mammogram test sets in different countries. The performance of the radiologists from less well-established breast screening countries such as China, Mongolia and Vietnam were significant lower in detecting early-stage cancers than radiologists from developed countries such as Australia, USA, Singapore, Italy. Differences in breast features and cancer presentations, discrepancies in the level of experiences in reading screening mammograms, the availability of high-quality national breast screening program and breast image interpretation training courses between developed and less developed countries are likely to have impact on the variation of readers’ performances. Hence dedicated education training programs with the ability to tailor to different reader cohorts and different population presentations are suggested to ameliorate challenges in exposure to a range of cancer cases and improve the interpretation skills of local radiologists. Findings from this review provide a good understanding of the radiologist’ performances and their improvement using the education interventions, primarily the BREAST program, which has been deployed in a large range of developing and developed countries in the last decade. Self-testing and immediate feedback loops have been shown to have important implications for benchmarking and improving the diagnostic accuracy in radiology worldwide for better breast cancer control.

Analyse causale de médiation multiple et applications

Thesis

Dec 2020

Allan Jérolon

L'analyse de médiation causale est une méthode statistique permettant d'étudier les mécanismes définissant les relations entre trois entités, la première étant une cause, la deuxième une variable de réponse et la troisième un ensemble de variables intermédiaires, aussi appelés médiateurs. Cette approche est devenue populaire dans différents domaines tels que les biostatistiques, l'épidémiologie et les sciences sociales. Son objectif est de décomposer et quantifier l'effet total d'une cause T sur une variable de réponse Y en un effet direct et un effet indirect à travers le(s)médiateur(s) Mi. Dans un diagramme causal ainsi défini peuvent intervenir des covariables mesurées ou non ayant des effets sur les trois variables T, Y et Mi. Quand plusieurs médiateurs sont impliqués dans le modèle de médiation, il y a trois cas possibles de relation entre ces médiateurs : 1) Les médiateurs sont indépendants conditionnellement au traitement et aux covariables mesurées. 2) Les médiateurs sont dépendants conditionnellement au traitement et aux covariables mesurées sans pour autant que l'un affecte l'autre. 3) Les médiateurs sont liés de façon causale, c'est-à-dire que l'un affecte l'autre. Les contributions de cette thèse portent sur les deux premières configurations. Plus particulièrement, l'état de l'art pour l'estimation des effets indirects individuels des médiateurs est de faire plusieurs analyses de médiation simple en parallèle, un médiateur à la fois. Cette approche conduit à une estimation biaisée de l'effet direct et n'est pas justifiée dans la situation 2) car l'hypothèse nécessaire d'Ignorabilité Séquentielle n'est alors pas vérifiée. Le premier chapitre de la thèse propose de résoudre ce problème par l'estimation de la loi multivariée des médiateurs conditionnellement au traitement et décrit les nouvelles hypothèses sous lesquelles une telle approche est valide. Une méthode d'estimation de l'effet direct et de tous les effets indirects individuels est développée, prenant en compte la corrélation entre les médiateurs. Le second chapitre est dédié à l'analyse de médiation multiple2/6dans le cas où le nombre de médiateurs grandit. Deux stratégies sont explorées. La première repose sur une classification spectrale des médiateurs en blocs indépendants, chaque bloc pouvant être analysé avec l'approche précédente. La seconde, applicable dans des problèmes de grande dimension, repose sur la sélection de médiateurs potentiels à l'aide d'une approche de type Group-LASSO en amont de l'analyse de médiation. Le troisième chapitre présente le packageR multimediate où les trois méthodes précédentes sont implémentées. On y présente l'algorithme d'estimation en fonction des différents types de médiateurs considérés (linéaires, binaires et catégoriels). Le dernier chapitre présente des applications sur des données réelles. D'une part une application en épidémiologie pour quantifier et décomposer l'effet de la thérapie hormonal sur le cancer du sein. D'autre part une application en psychiatrie, où nous analysons les effets des tempéraments affectifs sur l'anorexie mentale

Causal mediation analysis in presence of multiple mediators uncausally related

Article

Full-text available

Sep 2020

Mediation analysis aims at disentangling the effects of a treatment on an outcome through alternative causal mechanisms and has become a popular practice in biomedical and social science applications. The causal framework based on counterfactuals is currently the standard approach to mediation, with important methodological advances introduced in the literature in the last decade, especially for simple mediation, that is with one mediator at the time. Among a variety of alternative approaches, Imai et al. showed theoretical results and developed an R package to deal with simple mediation as well as with multiple mediation involving multiple mediators conditionally independent given the treatment and baseline covariates. This approach does not allow to consider the often encountered situation in which an unobserved common cause induces a spurious correlation between the mediators. In this context, which we refer to as mediation with uncausally related mediators, we show that, under appropriate hypothesis, the natural direct and joint indirect effects are non-parametrically identifiable. Moreover, we adopt the quasi-Bayesian algorithm developed by Imai et al. and propose a procedure based on the simulation of counterfactual distributions to estimate not only the direct and joint indirect effects but also the indirect effects through individual mediators. We study the properties of the proposed estimators through simulations. As an illustration, we apply our method on a real data set from a large cohort to assess the effect of hormone replacement treatment on breast cancer risk through three mediators, namely dense mammographic area, nondense area and body mass index.

Breast Development in Transwomen After One Year of Cross-sex Hormone Therapy: Results of A Prospective Multicenter Study

Article

Nov 2017

Context Breast development is a key feature of feminization and therefore important to transwomen (male-to-female transgender persons). However, it is not exactly known when breast development starts after initiating cross-sex hormone therapy (CHT) and how much growth may be expected of CHT alone. Objective To investigate breast development in centimeters and bra cup-sizes in transwomen during their first year of CHT, and whether clinical or laboratory parameters predict the breast development. Design This study was performed as part of the European Network for the Investigation of Gender Incongruence (ENIGI), which is a prospective multicenter cohort study. Setting Specialized gender clinics in Amsterdam, Ghent, and Florence. Participants All transwomen who completed the first year of CHT (n=229) were eligible for analyses. Intervention Cross-sex hormone therapy. Main outcome measures Breast development in centimeter and cup-size. Results The median age of the included transwomen was 28 years (range 18;69 years). Mean breast – chest difference increased from 4.1±2.9cm at baseline to 7.9±3.1cm after one year of CHT, mainly resulting in less than an AAA cup-size (48.7%). Main breast development occurred in the first six months of therapy. Serum estradiol levels did not predict breast development after one year CHT (first quartile: +3.6cm(95% CI +2.7;+4.5cm), second quartile: +3.2cm(95% CI +2.3;+4.2cm), third quartile: +4.4(95% CI +3.5;+5.3cm), fourth quartile: +3.6cm(95% CI +2.7;+4.5cm)). Conclusion This study shows that after one year of CHT breast development is modest and occurs primarily in the first six months. No clinical or laboratory parameters were found that predict breast development.

Do women with smaller breasts perform better in long-distance running?

Article

Jul 2016

Literature has established that a range of physiological, biomechanical, and training variables influence marathon performance. The influence of anthropometric characteristics has also received attention. However, despite major marathons exceeding 40,000 participants and approximately a third of these runners being female, no data exist on the influence of the breast on running performance. This cross-sectional study aimed to explore the impact of breast mass on marathon finish time. One hundred and sixty-eight of 321 female marathon runners contacted completed an on-line survey focusing on marathon performance during the 2012 London marathon. Participants were categorised as smaller (<500 g, 54%) or larger breasted (>500 g, 46%). Regression analysis identified that 24% of marathon performance variance could be explained by body mass index (BMI), but breast mass improved the model to explain 28% of performance variation. The model determined that for women with 32/34 or 36/38 underband each increase in cup size equates to a performance decrement of 4.6 min or 8.6 min, equivalent to 34.4 min difference between a woman with 36A compared to 36DD breast size. Larger breasted runners had greater BMIs, completed less marathons and had slower marathon finish times (316 ± 48 min) compared to smaller breasted runners (281 ± 51 min). Twenty-five per cent less larger breasted women finished in the fastest quartile. These results suggest that differences in breast mass are an important factor for female athletes and should be considered in future research in this area.

Breast development in male-to-female transgender patients after one year cross-sex hormonal treatment

Article

May 2016

Background: In male to female transgender patients breast development is a key part in the process of feminization using cross sex hormone therapy. In the Endocrine Societys clinical guideline Endocrine treatment of transsexual persons the onset of breast growth is estimated as 36 months after starting cross sex hormone treatment. The maximum breast growth however is seen after 23 years. But how much growth, in centimeters or cup-sizes, we can expect is not clear. With this in mind we want to objectify the breast growth after one year of cross sex hormone treatment in male to female transgender patients. Objective: To examine the absolute increase in breast circumference corrected for chest circumference in male to female transgender subjects included in the ENIGI database who are treated with cross sex hormone therapy for 1 year. Methods: All male to female transgender subjects included in the ENIGI database who have been treated with cross sex hormones for 1 year are eligible for this study. According to the ENIGI protocol patients are examined in the outpatient clinic every 3 months. During this outpatient clinic visits several features are examined and measured including breast and chest circumference. Missing values we imputed with multiple imputation(ICE) in Stata. Results: One-hundred-forty-two male to female subjects are eligible for this study. Mean breast circumference increased from 93.9 (S.D. 11.6) cm to 97.2 (11.1), while chest circumference remained stable (88.6 (10.7) cm). The mean difference between breast and chest diameter after one year was 7.5 (3.0) cm. This implicated a C-cup (1618 cm) in 2%, B-cup (1416) in 4%, A-cup (1214) in 8% and AA-cup (1012) in 10% of the patients. After 1 year, 76% had a breast-chest difference smaller than 10 cm. Conclusions: Our study shows a modest breast development after 1 year. Future studies need to determine whether breast circumference is an accurate method to estimate breast development during cross sex hormone treatment and what the effects are on longer treatment. Furthermore, a topic of interest is which factors influence breast development in transgender treatment.

Variants in 6q25.1 Are Associated with Mammographic Density in Malaysian Chinese Women

Article

Dec 2015

Background: Mammographic density is an established risk factor for breast cancer and has a strong heritable component. Genome-wide association studies (GWAS) for mammographic density conducted in women of European descent have identified several genetic associations, but none of the studies have been tested in Asians. We sought to investigate whether these genetic loci, and loci associated with breast cancer risk and breast size, are associated with mammographic density in an Asian cohort. Methods: We conducted genotyping by mass spectrometry in 1,189 women (865 Chinese, 187 Indian, and 137 Malay). Quantitative measurements of mammographic density were performed using ImageJ, a fully automated thresholding technique. The associations of SNPs to densities were analyzed using linear regression models. Results: We successfully evaluated the associations of 36 SNPs with mammographic densities. After adjusting for age, body mass index, parity, and menopausal status, we found that in our cohort of 865 Malaysian Chinese, three SNPs in the 6q25.1 region near ESR1 (rs2046210, rs12173570, and rs10484919) that were associated with mammographic density, breast cancer risk, or breast size in previous GWAS were significantly associated with both percentage density and absolute dense area. We could not replicate the most significant association found previously in European women (rs10995190, ZNF365 gene) because the minor allele was absent for Asian women. Conclusion: We found that the directions of genetic associations were similar to those reported in Caucasian women. Impact: Our results show that even in Asian women with lower population risk to breast cancer, there is shared heritability between mammographic density and breast cancer risk.

Breast reconstruction following conservative mastectomies: predictors of complications and outcomes

Article

Dec 2015

Breast reconstruction can be performed using a variety of techniques, most commonly categorized into an alloplastic approach or an autologous tissue method. Both strategies have certain risk factors that influence reconstructive outcomes and complication rates. In alloplastic breast reconstruction, surgical outcomes and complication rates are negatively impacted by radiation, smoking, increased body mass index (BMI), hypertension, and prior breast conserving therapy. Surgical factors such as the type of implant material, undergoing immediate breast reconstruction, and the use of fat grafting can improve patient satisfaction and aesthetic outcomes. In autologous breast reconstruction, radiation, increased BMI, certain previous abdominal surgery, smoking, and delayed reconstruction are associated with higher complication rates. Though a pedicled transverse rectus abdominis myocutaneous (TRAM) flap is the most common type of flap used for autologous breast reconstruction, pedicled TRAMs are more likely to be associated with fat necrosis than a free TRAM or deep inferior epigastric perforator (DIEP) flap. Fat grafting can also be used to improve aesthetic outcomes in autologous reconstruction. This article focuses on factors, both patient and surgical, that are predictors of complications and outcomes in breast reconstruction.

Effect of sports bra type and gait speed on breast discomfort, bra discomfort and perceived breast movement in Chinese women

Article

Aug 2015
ERGONOMICS

Unlabelled: This study investigated the effect of sports bra type (encapsulation versus compression) and gait speed on perceptions of breast discomfort, bra discomfort and breast movement reported by Chinese women. Visual analogue scales were used to evaluate breast discomfort, bra component discomfort and perceived breast movement of 21 Chinese participants when they wore an encapsulation or a compression sports bra, while static and while exercising at three different gait speeds. Participants perceived less breast discomfort and breast movement when wearing a compression bra compared to an encapsulation bra at a high gait speed, suggesting that compression bras are likely to provide the most effective support for Chinese women. However, significantly higher bra discomfort was perceived in the compression bra compared to the encapsulation bra when static and at the lower gait speed, implying that ways to modify the design of sports bras, particularly the straps, should be investigated to provide adequate and comfortable breast support. Practitioner summary: The compression sports bra provided more comfortable support than the encapsulation sports bra for these Chinese women when running on a treadmill. However, these women perceived higher bra discomfort when wearing the compression bra when stationary. Further research is needed to modify the design of sports bras, particularly the straps, to provide adequate and comfortable breast support.

Breast size and asymmetry during pregnancy in dependence of a fetus's sex: Breast morphology in pregnancy and fetal sex

Article

Mar 2015
AM J HUM BIOL

Objectives Breast size and fluctuating asymmetry (FA) are related to women's biological condition, as size correlates positively with fecundity, whereas FA correlates negatively with biological quality. We tested if breast volume, FA, and their changes during pregnancy are related to a fetus's sex. Women with bigger, symmetrical breasts, with a greater increase in size during pregnancy, should be more likely to carry a more ecologically sensitive and energetically demanding male fetus.Methods Ninety-three women participated in a 3-stage longitudinal study. 3D breast scans were performed in the first, second, and third trimester of pregnancy. As there was a small variation in pregnancy week at each research stage between the participants, the expected breast volume and FA values for the 12th, 22nd, and 32nd pregnancy week were calculated, basing on the obtained measurements. Those values were compared between mothers who carried a boy and mothers who carried a girl.ResultsAlthough women who carried a boy had somewhat larger breasts at each trimester than women who carried a girl, the difference was not significant. ANOVA for repeated measurements revealed a greater breast size increase in women carrying a boy (P = 0.039). FA decreased during pregnancy, but was not related to a fetus's sex.Conclusion Pregnancy-induced breast volume increase is a better cue of a fetus's sex than breast asymmetry or breast size per se, i.e., the traits that are supposed to indicate a woman's biological condition. Women with a larger increase in breast size during pregnancy are more likely to carry to term a more ecologically vulnerable male fetus. Am. J. Hum. Biol., 2015. © 2015 Wiley Periodicals, Inc.

A Twin Study of Breastfeeding With a Preliminary Genome-Wide Association Scan

Article

Dec 2014
TWIN RES HUM GENET

Breastfeeding has been an important survival trait during human history, though it has long been recognized that individuals differ in their exact breastfeeding behavior. Here our aims were, first, to explore to what extent genetic and environmental influences contributed to the individual differences in breastfeeding behavior; second, to detect possible genetic variants related to breastfeeding; and lastly, to test if the genetic variants associated with breastfeeding have been previously found to be related with breast size. Data were collected from a large community-based cohort of Australian twins, with 3,364 women participating in the twin modelling analyses and 1,521 of them included in the genome-wide association study (GWAS). Monozygotic (MZ) twin correlations (r MZ = 0.52, 95% CI 0.46-0.57) were larger than dizygotic (DZ) twin correlations (r DZ = 0.35, 95% CI 0.25-0.43) and the best-fitting model was the one composed by additive genetics and unique environmental factors, explaining 53% and 47% of the variance in breastfeeding behavior, respectively. No breastfeeding-related genetic variants reached genome-wide significance. The polygenic risk score analyses showed no significant results, suggesting breast size does not influence breastfeeding. This study confers a replication of a previous one exploring the sources of variance of breastfeeding and, to our knowledge, is the first one to conduct a GWAS on breastfeeding and look at the overlap with variants for breast size.

Attractiveness of women's body: Body mass index, waist-hip ratio, and their relative importance

Article

Full-text available

Jul 2013

Krzysztof Kościński

Body mass index and waisthip ratio are related to human health and both play a role in mate choice. However, previous research is inconsistent as to what body mass index and waisthip ratio values are preferred in women and what the relative importance of body mass index and waisthip ratio for attractiveness is. Here, we made several methodological refinements to obtain reliable estimations. Participants (Poles) indicated the most attractive woman from a set of digitally manipulated high-quality silhouettes varying orthogonally in body mass index and waisthip ratio and viewed from behind to exclude effects of the breast size. Then, each participant chose the more attractive silhouette from pairs in which one figure deviated from his/her ideal in body mass index and the other in waisthip ratio. Both sexes preferred underweight women (body mass index 17.3) with accentuated waist (waisthip ratio 0.66 for female and 0.70 for male judges). These represent preferences for unhealthy body mass and healthy body shape. Furthermore, body mass index proved twice as important for attractiveness as waisthip ratio, even though literature data indicate that waisthip ratio is at least as important for health as body mass index. We discuss the obtained pattern of preferences from the perspective of evolutionary psychology.

Significantly greater reduction in breast cancer mortality from post-diagnosis running than walking

Article

Sep 2014
INT J CANCER

Paul Williams

The purpose of these analyses is to test prospectively whether post-diagnosis running and walking differ significantly in their association with breast cancer mortality. Cox proportional hazard analyses were used to compare breast cancer mortality to baseline exercise energy expenditure (METs, 1 MET-hour ~ 1 km run) in 272 runners and 714 walkers previously diagnosed with breast cancer from the National Runners' and Walkers' Health Studies when adjusted for age, race, menopause, family history, breastfeeding and oral contraceptive use. Diagnosis occurred (mean±SD) 7.9±7.3 years prior to baseline. Forty-six women (13 runners, 33 walkers) died from breast cancer during 9.1-year mortality surveillance. For the 986 runners and walkers combined, breast cancer mortality decreased an average of 23.9% MET-hours/d (95%CI: 7.9% to 38.3%; P=0.004). There was a significantly greater decrease in risk for running than walking (risk per MET-hours/d run vs. walked: P=0.03). For the 272 runners analyzed separately, breast cancer mortality decrease an average of 40.9% per MET-hours/d run (95%CI: 19.3% to 60.0%, P=0.0004). When analyzed by categories of running energy expenditure, breast cancer mortality was 87.4% lower for the 1.8 to 3.6 MET-hours/d category (95%CI: 41.3% to 98.2% lower, P=0.008) and 95.4% lower for the ≥3.6 MET-hours/d category (95%CI: 71.9% to 100% lower, P=0.0004) compared to the <1.07 MET-hours/d category. In contrast, the 714 walkers showed a non-significant 4.6% decrease in breast cancer mortality per MET-hours/d walked (95%CI: 27.3% decrease risk to 21.3% increased risk, P=0.71). These results suggest that post-diagnosis running is associated with significantly lower breast cancer mortality than post-diagnosis walking. © 2014 Wiley Periodicals, Inc.

Breast Cancer Mortality vs. Exercise and Breast Size in Runners and Walkers

Article

Full-text available

Dec 2013
PLOS ONE

Paul Williams

Identify predictors of breast cancer mortality in women who exercised below (<7.5 metabolic equivalent hours/week, MET-hours/wk), at (7.5 to 12.5 MET-hours/wk), or above (≥12.5 MET-hours/wk) recommended levels. Cox proportional hazard analyses of baseline pre-diagnosis MET-hours/wk vs. breast cancer mortality adjusted for follow-up age, race, baseline menopause, and estrogen and oral contraceptive use in 79,124 women (32,872 walkers, 46,252 runners) from the National Walkers' and Runners' Health Studies. One-hundred eleven women (57 walkers, 54 runners) died from breast cancer during the 11-year follow-up. The decline in mortality in women who exercised ≥7.5 MET-hours/wk was not different for walking and running (P = 0.34), so running and walking energy expenditures were combined. The risk for breast cancer mortality was 41.5% lower for ≥7.5 vs. <7.5 MET-hours/wk (HR: 0.585, 95%CI: 0.382 to 0.924, P = 0.02), which persisted when adjusted for BMI (HR: 0.584, 95%CI: 0.368 to 0.956, P = 0.03). Other than age and menopause, baseline bra cup size was the strongest predictor of breast cancer mortality, i.e., 57.9% risk increase per cup size when adjusted for MET-hours/wk and the other covariates (HR: 1.579, 95%CI: 1.268 to 1.966, P<0.0001), and 70.4% greater when further adjusted for BMI (HR: 1.704, 95%CI: 1.344 to 2.156, P = 10(-5)). Breast cancer mortality was 4.0-fold greater (HR: 3.980, 95%CI: 1.894 to 9.412, P = 0.0001) for C-cup, and 4.7-fold greater (HR: 4.668, 95%CI: 1.963 to 11.980, P = 0.0004) for ≥D-cup vs. A-cup when adjusted for BMI and other covariates. Adjustment for cup size and BMI did not eliminate the association between breast cancer mortality and ≥7.5 MET-hour/wk walked or run (HR: 0.615, 95%CI: 0.389 to 1.004, P = 0.05). Breast cancer mortality decreased in association with both meeting the exercise recommendations and smaller breast volume.

Breast size, thoracic kyphosis & thoracic spine pain - association & relevance of bra fitting in post-menopausal women: A correlational study

Article

Full-text available

Jul 2013

Menopause would seem to exist as a period of accelerated changes for women and their upper torso mechanics. Whether these anthropometric changes reflect changes in pain states remains unclear. Plausible mechanisms of pain exist for the independent and combined effect of increasing breast size and thoracic kyphosis. Bra fit has the potential to change when the anthropometric measures (chest circumference and bust circumference) used to determine bra size change, such as postmenopausally.Identifying an association between breast size, thoracic kyphosis and thoracic spine pain in postmenopausal women and identifying the relevance of bra fit to this association may be of importance to the future management and education of post-menopausal women presenting clinically with thoracic spine pain. A cross-sectional study design. Fifty-one postmenopausal bra-wearing women were recruited. Measures included breast size (Triumph International), thoracic kyphosis (flexible curve), bra fitted (Y/N) and pain (Short Form McGill Pain Questionnaire) and tenderness on palpation (posteroanterior pressure testing). These measures were collected in one session at a physiotherapy clinic. The majority of the women in this study were overweight or obese and wearing an incorrect sized bra. Pain was significantly related to breast size, body weight and BMI at mid thoracic levels (T7-8). In contrast self-reported thoracic pain was not correlated with age or index of kyphosis (thoracic kyphosis). Women with thoracic pain were no more likely to have their bra professionally fitted whereas women with a higher BMI and larger breasts were more likely to have their bra professionally fitted. The findings of this study show that larger breasts and increased BMI are associated with thoracic pain in postmenopausal women. This is unrelated to thoracic kyphosis. Increasing breast size and how a bra is worn may have biomechanical implications for the loaded thoracic spine and surrounding musculature. Post-menopause women present with a spectrum of anthropometrical changes that have the potential to contribute to altered biomechanics and affect pain states in the thoracic spine.

Determinants of Breast Appearance and Aging in Identical Twins

Article

Full-text available

Sep 2012
Aesthetic Surg J

Appearance, aging, and disorders of the breast are multifactorial. There are intrinsic, patient-specific characteristics, such as breast growth during puberty and propensity for breast cancer, which are primarily inherited. There are also environmental factors, which can be potentially controlled. Monozygotic twins provide an excellent research opportunity to examine the role of extrinsic factors in subjects with identical genetic predispositions. The authors investigate the role and significance of various environmental and acquired factors on breast aesthetics. Identical female twins were recruited during the Twins Days Festival in Twinsburg, Ohio, in 2009 and 2010. After consent was obtained, enrolled subjects completed a comprehensive survey on their medical and personal history. Standardized digital photographs were taken by medical photographers. Sixteen aesthetic breast features were subjectively rated by 6 plastic surgery residents blinded to the survey results. These ratings were then analyzed against survey data to determine the significance of different exogenous factors on breast appearance. A total of 161 pairs of identical female twins (n = 322) with a mean (SD) age of 47.6 (14.5) years were recruited. Twins who moisturized their skin daily had significantly fewer rhytids (P = .002). Twins who received hormone replacement therapy after menopause had more attractive breast shape, size, projection, areolar shape, and areolar size (P < .03). However, twins who had a higher body mass index, greater number of pregnancies, and larger cup sizes had significantly less attractive breasts (P < .05). Twins who smoked cigarettes and consumed alcohol also had significantly less attractive breasts (P < .05). Twins who breastfed had less attractive areolar size and shape but better skin quality than their counterparts who never breastfed (P < .03). Finally, there was a significantly higher incidence of breast pain in twins who primarily slept on their sides compared with twins who primarily slept on their backs (P < .008). This study implicates several environmental factors that significantly affect the aesthetic quality of breasts.

Genetic variants associated with breast size also influence breast cancer risk

Article

Full-text available

Jun 2012
BMC MED GENET

Background While some factors of breast morphology, such as density, are directly implicated in breast cancer, the relationship between breast size and cancer is less clear. Breast size is moderately heritable, yet the genetic variants leading to differences in breast size have not been identified. Methods To investigate the genetic factors underlying breast size, we conducted a genome-wide association study (GWAS) of self-reported bra cup size, controlling for age, genetic ancestry, breast surgeries, pregnancy history and bra band size, in a cohort of 16,175 women of European ancestry. Results We identified seven single-nucleotide polymorphisms (SNPs) significantly associated with breast size (p<5·10−8): rs7816345 near ZNF703, rs4849887 and (independently) rs17625845 flanking INHBB, rs12173570 near ESR1, rs7089814 in ZNF365, rs12371778 near PTHLH, and rs62314947 near AREG. Two of these seven SNPs are in linkage disequilibrium (LD) with SNPs associated with breast cancer (those near ESR1 and PTHLH), and a third (ZNF365) is near, but not in LD with, a breast cancer SNP. The other three loci (ZNF703, INHBB, and AREG) have strong links to breast cancer, estrogen regulation, and breast development. Conclusions These results provide insight into the genetic factors underlying normal breast development and show that some of these factors are shared with breast cancer. While these results do not directly support any possible epidemiological relationships between breast size and cancer, this study may contribute to a better understanding of the subtle interactions between breast morphology and breast cancer risk.

Chest Feminization in Male-to-Female Transgender Patients: A Review of Options

Article

Jan 2021

Management of a transgender (TG) woman's gender dysphoria is individualized to address the sources of her distress. This typically involves some combination of psychological therapy, hormone modulation, and surgical intervention. Breast enhancement is the most commonly pursued physical modification in this population. Because hormone manipulation provides disappointing results for most TG women, surgical treatment is frequently required to achieve the goal of a feminine chest. Creating a female breast from natal male chest anatomy poses significant challenges; the sexual dimorphism requires a different approach than that used in cisgender breast augmentation. The options and techniques used continue to evolve as experience in this field grows.

Relationship of breast volume, obesity and central obesity with different prognostic factors of breast cancer

Article

Full-text available

Jan 2021

The objective of this study was to investigate whether the BC tumor biology in women with larger breast volume, in obese women and especially in women with central adiposity at the moment of diagnosis of BC is more aggressive than in those women without these characteristics. 347 pre- and postmenopausal women with a recent diagnosis of BC were analyzed. In all patients, anthropometric measurements at the time of diagnosis was collected. In 103 of them, the breast volume was measured by the Archimedes method. The Breast volume, BMI, WHR and the menopausal status were related to different well-known pathological prognostic factors for BC. At the time of diagnosis, 35.4% were obese (BMI > 30 kg/m ² ), 60.2% had a WHR ≥ 0.85, 68.8% were postmenopausal and 44.7% had a breast volume considered "large" (> 600 cc). Between patients with a large breast volume, only a higher prevalence of ER (+) tumors was found (95.3% vs. 77.2%; p = 0.04) compared to those with small breast volumes. The obese BC patients showed significantly higher rates of large tumors (45.5% vs. 40.6%; p = 0.04), axillary invasion (53.6% vs. 38.8%; p = 0.04), undifferentiated tumors (38.2% vs. 23.2%) and unfavorable NPI ( p = 0.04) than non-obese women. Those with WHR ≥ 0.85 presented higher postsurgical tumor stages (61.7% vs. 57.8%; p = 0.03), higher axillary invasion (39.9% vs. 36.0%; p = 0.004), more undifferentiated tumors (30.0% vs. 22.3%; p = 0.009), higher lymphovascular infiltration (6.5% vs. 1.6%; p = 0.02), and a higher NPI (3.6 ± 1.8 vs. 3.2 ± 1.8; p = 0.04). No statistically significant differences were found according to menopausal status. We conclude that obesity, but especially central obesity can be associated with a more aggressive tumour phenotype. No relation between breast volume and tumoral prognostic factors was found, except for a higher proportion of ER (+) tumor in women with higher breast volume.

The Effect of Obesity on Operating Room Utilization in Breast Surgery

Article

Apr 2021

Background The current obesity epidemic is associated with increased health care costs associated with comorbidities such as diabetes and heart disease as well as postoperative complications. However, the effect of obesity on operating room (OR) utilization, especially in common breast procedures, has not been completely evaluated. Our study is the first to examine the effect of patient obesity on operative time (OPT) for common breast procedures. Methods The American College of Surgeons National Surgical Quality Improvement Project databases for 2010-2018 were searched for this retrospective review. Patients undergoing common breast operations (lumpectomy, lumpectomy with sentinel lymph node biopsy (SLNB) (+/− injection), lumpectomy and axillary lymph node dissection (ALND), simple mastectomy, mastectomy with SLNB (+/− injection), and mastectomy with ALND) were filtered out by Current Procedural Terminology code and divided into three groups based on their body mass index (BMI) and weight. Using the two-sample t-test, OPT for the procedures was compared among the lowest and highest BMI and weight categories. We also used a linear regression t-test to demonstrate that for every unit increase in BMI, there was a corresponding increase in OPT for each procedure. Results When the lowest and highest BMI and weight groups were compared, significant differences in OPT (P < 0.0001) were seen for each of the procedures. Numerous factors that could affect the complexity of surgery and thus OR time were identified. The correlation between BMI and weight and OPT remained significant after controlling for these variables. The differences between the highest and lowest BMI groups were most pronounced for higher complexity procedures, such as lumpectomy with ALND and mastectomy with ALND, with average operating times increasing by 18.2 min and 18.6 min, respectively, for patients with a higher BMI. Conclusions Patient BMI and weight significantly affect OPT for common breast procedures. Therefore, patient BMI should be taken into account to improve OR scheduling.

Breast firmness is of greater importance for women's attractiveness than breast size

Article

Jun 2019

Krzysztof Kościński

Objectives: Male preferences are believed to have played a role in the evolution of permanently enlarged breasts in human females. Although breast size and shape are proven to affect women's attractiveness, their relative importance has not been investigated thus far. We aime to address this gap. Methods: We prepared two sets of stimuli, each comprising 49 high-quality color images of a topless woman in a three-quarter view that varied in breast size (from 1 to 7) and firmness (from 1 to 7). Set A depicted the glandular ptosis (ie, breast shape being manipulated but the nipple always directed forward), while Set B depicted true ptosis (both breast shape and nipple position being manipulated). Participants (aged 18-45) were assigned to Set A (62 women, 60 men) or Set B (76 women, 52 men). First, each participant indicated the most attractive woman in the set of images. Next, the participant chose the more attractive woman from pairs in which one female deviated from the participant's ideal in breast size and the other in breast firmness. Results: Both men and women preferred breasts of average or slightly above-average size and high or extreme firmness. Glandular ptosis was as important for attractiveness as breast size, but true ptosis was of much greater importance. Men preferred slightly bigger breasts than women. Conclusions: Further attempts to explain evolution of permanent breasts in human females should give greater attention to breast shape than has previously been the case.

Genetic Studies of Endophenotypes From Spine CT Scans Provide Novel Insights Into the Contribution of Mechanosensory Pathways to Vertebral Fractures and Spinal Curvature

Article

Nov 2016
J BONE MINER RES

In the current issue of the Journal, Yau et al report a heritability study based on computed tomography (CT) scans, intended to quantify genetic influences on thoracic spinal curvature. In the same issue, Nielson et al report a genome wide association study (GWAS) of CT-derived lumbar spine volumetric bone mineral density (vBMD), followed by a ‘look up’ of associations with vertebral fracture. Taken together, these papers demonstrate that studying endophenotypes derived from spine CT scans provides important insights into genetic influences on vertebral fractures and spinal deformity, including a possible role of mechanosensory pathways acting via vertebral BMD. This article is protected by copyright. All rights reserved

Given breast cancer, does breast size matter? Data from a prospective breast cancer cohort

Article

Jun 2012
CANCER CAUSE CONTROL

Body mass index (BMI), waist-to-hip ratio (WHR), and tumor characteristics affect disease-free survival. Larger breast size may increase breast cancer risk, but its influence on disease-free survival is unclear. The purpose of this study was to elucidate whether breast size independently influenced disease-free survival in breast cancer patients. Body measurements were obtained preoperatively from 772 breast cancer patients in a population-based ongoing cohort from southern Sweden. The research nurse measured breast volumes with plastic cups used by plastic surgeons doing breast reductions. Clinical data were obtained from patient charts and pathology reports. Patients with a BMI ≥ 25 kg/m(2) had larger tumors (p < 0.001) and more axillary nodal involvement (p = 0.030). Patients with a WHR > 0.85 had larger tumors (p = 0.013), more advanced histological grade (p = 0.0016), and more axillary nodal involvement (p = 0.012). Patients with right + left breast volume ≥ 850 mL were more likely to have larger tumor sizes (p = 0.018), more advanced histological grade (p = 0.031), and more axillary nodal involvement (p = 0.025). There were 62 breast cancer events during the 7-year follow-up. Breast volume ≥ 850 mL was associated with shorter disease-free survival (p = 0.004) and distant metastasis-free survival (p = 0.001) in patients with estrogen receptor (ER)-positive tumors independent of other anthropometric measurements and age. In patients with ER-positive tumors, breast size was an independent predictor of shorter disease-free (HR 3.64; 95 % CI 1.42-9.35) and distant metastasis-free survival (HR 6.33; 95 %CI 1.36-29.43), adjusted for tumor characteristics, BMI, age, and treatment. A simple and cheap anthropometric measurement with standardized tools may help identify a subgroup of patients in need of tailored breast cancer therapy.

Body weight, waist-to-hip ratio and breast size correlates of ratings of attractiveness and health

Article

Full-text available

Aug 2006
PERS INDIV DIFFER

This study looked at the contribution of body weight, breast size and waist-to-hip ratio (WHR) in ratings of female attractiveness, femininity, health and fecundity. One hundred and fifty eight participants rated 36 line drawings that varied 2 levels of breast size, 3 of body weight and 6 of WHR. Whilst there was evidence of some differences between the four ratings there was a clear pattern. Effect sizes were higher for WHR (0.34–0.52) than body weight (0.14–0.31), whilst there were no main effects for breast size. The body weight×WHR interactions were marginally significant while WHR×breast size interactions had effect sizes ranging from 0.16 to 0.23. Work in this area appears to yield different results and conclusions depending on the stimulus materials used and the data analysis method employed.

Predictors of NonResponse to a Questionnaire Survey of a Volunteer Twin Panel: Findings from the Australian 1989 Twin Cohort

Article

Full-text available

Apr 2001
Twin Res

uestionnaire surveys, while more economical, typically achieve poorer response rates than interview surveys. We used data from a national volunteer cohort of young adult twins, who were scheduled for assessment by questionnaire in 1989 and by interview in 1996-2000, to identify predictors of question- naire non-response. Out of a total of 8536 twins, 5058 completed the questionnaire survey (59% response rate), and 6255 completed a telephone interview survey conducted a decade later (73% response rate). Multinomial logit models were fitted to the interview data to identify socioeconomic, psy- chiatric and health behavior correlates of non-response in the earlier questionnaire survey. Male gender, education below University level, and being a dizygotic rather than monozygotic twin, all predicted reduced likelihood of participating in the ques- tionnaire survey. Associations between questionnaire response status and psychiatric history and health behavior variables were modest, with history of alcohol dependence and childhood conduct disorder predicting decreased probability of returning a questionnaire, and history of smoking and heavy drinking more weakly associated with non-response. Body-mass index showed no association with questionnaire non-response. Despite a poor response rate to the self-report questionnaire survey, we found only limited sampling biases for most vari- ables. While not appropriate for studies where socioeconomic variables are critical, it appears that survey by questionnaire, with questionnaire administration by telephone to non-respon- ders, will represent a viable strategy for gene-mapping studies requiring that large numbers of relatives be screened.

Genetic and Environmental Factors in Relative Body Weight and Human Adiposity

Article

Full-text available

Jul 1997

We review the literature on the familial resemblance of body mass index (BMI) and other adiposity measures and find strikingly convergent results for a variety of relationships. Results from twin studies suggest that genetic factors explain 50 to 90% of the variance in BMI. Family studies generally report estimates of parent-offspring and sibling correlations in agreement with heritabilities of 20 to 80%. Data from adoption studies are consistent with genetic factors accounting for 20 to 60% of the variation in BMI. Based on data from more than 25,000 twin pairs and 50,000 biological and adoptive family members, the weighted mean correlations are .74 for MZ twins, .32 for DZ twins, .25 for siblings, .19 for parent-offspring pairs, .06 for adoptive relatives, and .12 for spouses. Advantages and disadvantages of twin, family, and adoption studies are reviewed. Data from the Virginia 30,000, including twins and their parents, siblings, spouses, and children, were analyzed using a structural equation model (Stealth) which estimates additive and dominance genetic variance, cultural transmission, assortative mating, nonparental shared environment, and special twin and MZ twin environmental variance. Genetic factors explained 67% of the variance in males and females, of which half is due to dominance. A small proportion of the genetic variance was attributed to the consequences of assortative mating. The remainder of the variance is accounted for by unique environmental factors, of which 7% is correlated across twins. No evidence was found for a special MZ twin environment, thereby supporting the equal environment assumption. These results are consistent with other studies in suggesting that genetic factors play a significant role in the causes of individual differences in relative body weight and human adiposity.

Women's Health Australia: Recruitment for a National Longitudinal Cohort Study

Article

Full-text available

Feb 1998

The Women's Health Australia (WHA) project is a longitudinal study of several cohorts of Australian women, which aims to examine the relationships between biological, psychological, social and lifestyle factors and women's physical health, emotional well-being, and their use of and satisfaction with health care. Using the Medicare database as a sampling frame (with oversampling of women from rural and remote areas), 106,000 women in the three age groups 18-23, 45-50 and 70-75 were sent an invitation to participate and a 24-page self-complete questionnaire. Reminder letters, a nation-wide publicity campaign, information brochures, a freecall number for inquiries, and the option of completing the questionnaire by telephone in English or in the respondent's own language, were used to encourage participation. Statutory regulations precluded telephone follow-up of non-respondents. Response rates were 41% (N = 14,792), 54% (N = 14,200) and 36% (N = 12,614) for the three age groups. Comparison with Australian census data indicated that the samples are reasonably representative of Australian women in these age groups, except for a somewhat higher representation of women who are married or in a defacto relationship, and of women with post-school education. The most common reason for non-participation was lack of interest or time. Personal circumstances, objections to the questionnaire or specific items in it, and concerns about confidentiality were the other main reasons. Recruitment of three representative age-group cohorts of women, and the maintenance of these cohorts over a number of years, will provide a valuable opportunity to examine associations over time between aspects of women's lives and their physical and emotional health and well-being.

Genetic and environmental influences on waist-to-hip ratio and waist circumference in an older Swedish twin population

Article

Full-text available

Jun 1999

To investigate the genetic and environmental influences on waist-to-hip ratio (WHR) and waist circumference (WC) measurements in males and females. Measurements taken from 1989-1991 as part of The Swedish Adoption/Twin Study of Aging (SATSA) were used for analysis. The SATSA sample contains both twins reared together as well as twins reared apart. 322 pairs of twins (50 identical, 82 fraternal male pairs and 67 identical, 123 fraternal female pairs); age range: 45-85y (average age, 65y). Waist-to-hip ratio (WHR), waist circumference (WC) and body mass index (BMI). In males, additive genetic effects were found to account for 28% of the variance in WHR and 46% of the variance in WC. In females, additive genetic effects were found to account for 48% of the variance in WHR and 66% of the variance in WC. The remaining variance in males was attributed to unique environmental effects (WHR, 72%; WC, 54%) and in females the remaining variance was attributed to unique environmental effects (WHR, 46%; WC, 34%) and age (WHR, 6%). When BMI was added into these models it accounted for a portion of the genetic and environmental variance in WHR, and over half of the genetic and environmental variance in WC. There are both genetic and environmental influences on WHR and WC, independent of BMI in both males and females, and the differences between the sexes are significantly different.

Sex Differences in Heritability of BMI: A Comparative Study of Results from Twin Studies in Eight Countries

Article

Full-text available

Nov 2003
Twin Res

Body mass index (BMI), a simple anthropometric measure, is the most frequently used measure of adiposity and has been instrumental in documenting the worldwide increase in the prevalence of obesity witnessed during the last decades. Although this increase in overweight and obesity is thought to be mainly due to environmental changes, i.e., sedentary lifestyles and high caloric diets, consistent evidence from twin studies demonstrates high heritability and the importance of genetic differences for normal variation in BMI. We analysed self-reported data on BMI from approximately 37,000 complete twin pairs (including opposite sex pairs) aged 20-29 and 30-39 from eight different twin registries participating in the GenomEUtwin project. Quantitative genetic analyses were conducted and sex differences were explored. Variation in BMI was greater for women than for men, and in both sexes was primarily explained by additive genetic variance in all countries. Sex differences in the variance components were consistently significant. Results from analyses of opposite sex pairs also showed evidence of sex-specific genetic effects suggesting there may be some differences between men and women in the genetic factors that influence variation in BMI. These results encourage the continued search for genes of importance to the body composition and the development of obesity. Furthermore, they suggest that strategies to identify predisposing genes may benefit from taking into account potential sex specific effects.

Large breast and narrow waist indicate high reproductive potential in women

Article

Full-text available

Jul 2004

Physical characteristics, such as breast size and waist-to-hip ratio (WHR), function as important features used by human males to assess female attractiveness. Males supposedly pay attention to these features because they serve as cues to fecundity and health. Here, we document that women with higher breast-to-underbreast ratio (large breasts) and women with relatively low WHR (narrow waists) have higher fecundity as assessed by precise measurements of daily levels of 17-beta-oestradiol (E2) and progesterone. Furthermore, women who are characterized by both narrow waists and large breasts have 26% higher mean E2 and 37% higher mean mid-cycle E2 levels than women from three groups with other combinations of body-shape variables, i.e. low WHR with small breasts and high WHR with either large or small breasts. Such gains in hormone levels among the preferred mates may lead to a substantial rise in the probability of conception, thus providing a significant fitness benefit.

Mammographic Densities and Breast Cancer Risk

Article

Full-text available

Sep 1998

Variations between individuals in the radiographic appearance, or mammographic pattern, of the female breast arise because of differences in the relative amounts and X-ray attenuation characteristics of fat and connective and epithelial tissue. Studies using quantitative methods of assessment have consistently shown these variations to be strongly related to risk of breast cancer. Individuals with extensive areas of radiologically dense breast tissue on the mammogram have been found to have a risk of breast cancer that is four to six times higher than women with little or no density. In this paper, we propose a model for the relationship of mammographic densities to risk of breast cancer. We propose that the risk of breast cancer associated with mammographically dense breast tissue is due to the combined effects of two processes: cell proliferation (mitogenesis), induced by growth factors and sex hormones and influenced by reproductive risk factors for breast cancer; and damage to the DNA of dividing cells (mutagenesis) by mutagens generated by lipid peroxidation. We review the evidence that each of these processes is associated with mammographic densities and propose further work that we believe should be done to clarify these relationships.

Accuracy of Body Mass Index Categories Based on Self-Reported Height and Weight Among Women in the United States

Article

Full-text available

Aug 2008
MATERN CHILD HLTH J

The purpose of this study was to assess the accuracy of BMI categories based on self-reported height and weight in adult women. BMI categories from self-reported responses were compared to categories measured during physical examination from women, age 18 or older, who participated in the National Health and Examination Survey, 1999-2004. We first examined strength of agreement using Cohen's kappa, which, unlike sensitivity and specificity, allows for the comparison of polychotomous measures beyond chance agreement. Kappa regression identifies potential threats to accuracy. Likelihood of bias, as measured by under-reporting, was examined using logistic regression. Cohen's kappa estimates were 0.443 for pregnant women (N = 724) and 0.705 for non-pregnant women (N = 5,910). Kappa varied by age and race, but was largely unrelated to socioeconomic status, health and health behaviors. Women who visited a physician in the last year or been diagnosed with osteoporosis were more accurate, while women most likely to under-report were older, white, non-Hispanic, and college-educated. Our results suggest substantial agreement between self-reported and measured categories, except for women who are pregnant, above the age of 75 or without physician visits. Under-reporting may be more prevalent in well-educated, white populations than minority populations.

Men's preferences for women's profile waist-to-hip ratio, breast size, and ethnic group in Britain and South Africa

Article

Full-text available

Aug 2008

One particular aspect of the literature on preferences for female body shapes has focused on the purported universality of preferences for a low waist-to-hip ratio (WHR), despite substantial evidence of cross-cultural variability in such preferences. In the present study, we examined the effects of manipulating women's profile WHR, breast size, and ethnicity on men's ratings of physical attractiveness and health. A total of 51 African men in South Africa, 56 British Africans, and 114 British Caucasians rated 12 line drawings that varied in two levels of ethnicity, three levels of WHR, and two levels of breast size. Overall, the results suggested that there were cross-cultural differences in preferred body shape, with the preferred body configuration varying as a function of the ethnicity of the figure being rated. In addition, there was a strong positive correlation between ratings of attractiveness and health. These findings are discussed in relation to the interplay between culture and evolution in determining ideals of attractiveness.

Statistical Analysis with Missing Data.

Article

Jan 1989

Predictors of Non-Response to a Questionnaire Survey of a Volunteer Twin Panel: Findings from the Australian 1989 Twin Cohort

Article

Apr 2001
TWIN RES HUM GENET

Questionnaire surveys, while more economical, typically achieve poorer response rates than interview surveys. We used data from a national volunteer cohort of young adult twins, who were scheduled for assessment by questionnaire in 1989 and by interview in 1996-2000, to identify predictors of questionnaire non-response. Out of a total of 8536 twins, 5058 completed the questionnaire survey (59% response rate), and 6255 completed a telephone interview survey conducted a decade later (73% response rate). Multinomial logit models were fitted to the interview data to identify socioeconomic, psychiatric and health behavior correlates of non-response in the earlier questionnaire survey. Male gender, education below University level, and being a dizygotic rather than monozygotic twin, all predicted reduced likelihood of participating in the questionnaire survey. Associations between questionnaire response status and psychiatric history and health behavior variables were modest, with history of alcohol dependence and childhood conduct disorder predicting decreased probability of returning a questionnaire, and history of smoking and heavy drinking more weakly associated with non-response. Body-mass index showed no association with questionnaire non-response. Despite a poor response rate to the self-report questionnaire survey, we found only limited sampling biases for most variables. While not appropriate for studies where socioeconomic variables are critical, it appears that survey by questionnaire, with questionnaire administration by telephone to non-responders, will represent a viable strategy for gene-mapping studies requiring that large numbers of relatives be screened.

PRELIS 2: User´s reference guide

Book

Jan 1996

The Performance of the Full Information Maximum Likelihood Estimator in Multiple Regression Models with Missing Data

Article

Oct 2001
EDUC PSYCHOL MEAS

Craig K. Enders

A Monte Carlo simulation examined the performance of a recently available full information maximum likelihood (FIML) estimator in a multiple regression model with missing data. The effects of four independent variables were examined (missing data technique, missing data rate, sample size, and correlation magnitude) on three outcome measures regression coefficient bias, R-2 bias, and regression coefficient sampling variability. Three missing data patterns were examined based on Rubin's missing data theory: missing completely at random, missing at random, and a nonrandom. pattern. Results indicated that FIML estimation was superior to the three ad hoc techniques (listwise deletion, pairwise deletion, and mean imputatiom) across the conditions studied, FM parameter estimates generally had less bias and less sampling variability than the three ad hoc methods.

MX: Statistical Modeling

Book

Jan 1994

Michael C Neale

Hypothesis for the Evolution of Human Breasts and Buttocks

Article

Feb 1981

John G. H. Cant

Statistical Analysis With Missing Data

Article

Aug 1989

The Performance of the Full Information Maximum Likelihood Estimator in Multiple Regression Models With Missing Data

Article

Oct 2001
EDUC PSYCHOL MEAS

Craig K. Enders

A Monte Carlo simulation examined the performance of a recently available full information maximum likelihood (FIML) estimator in a multiple regression model with missing data. The effects of four independent variables were examined (missing data technique, missing data rate, sample size, and correlation magnitude) on three outcome measures: regression coefficient bias, R 2 bias, and regression coefficient sampling variability. Three missing data patterns were examined based on Rubin’s missing data theory: missing completely at random, missing at random, and a nonrandom pattern. Results indicated that FIML estimation was superior to the three ad hoc techniques (listwise deletion, pairwise deletion, and mean imputation) across the conditions studied. FIML parameter estimates generally had less bias and less sampling variability than the three ad hoc methods.

Breast asymmetry, sexual selection, and human reproductive success

Article

May 1995

Breasts of human females are large compared to those of closely related primate species, and they can thus be hypothesized recently or currently to have been subject to directional sexual selection. Here we show that (1) large breasts have higher levels of fluctuating asymmetry than small breasts, (2) breast fluctuating asymmetry is higher in women without children than in women with at least one child, (3) breast fluctuating symmetry is a reliable predictor of age-independent fecundity, and (4) breast fluctuating symmetry appears to be associated with sexual selection. These conclusions were similar in studies from two cultures differing in fecundity and breastfeeding traditions (Spain; New Mexico, U.S.A.). Choosy males that prefer females with symmetrical breasts may experience a direct fitness benefit in terms of increased fecundity and an indirect benefit in terms of attractive or fecund daughters.

Statistical Analysis With Missing Data

Book

Jan 1987

Factor analysis and the AIC

Article

Feb 1987
PSYCHOMETRIKA

Hirotugu Akaike

The information criterion AIC was introduced to extend the method of maximum likelihood to the multimodel situation. It was obtained by relating the successful experience of the order determination of an autoregressive model to the determination of the number of factors in the maximum likelihood factor analysis. The use of the AIC criterion in the factor analysis is particularly interesting when it is viewed as the choice of a Bayesian model. This observation shows that the area of application of AIC can be much wider than the conventional i.i.d. type models on which the original derivation of the criterion was based. The observation of the Bayesian structure of the factor analysis model leads us to the handling of the problem of improper solution by introducing a natural prior distribution of factor loadings.

Mammary Gland Mass and Breast Cancer Risk

Article

Dec 1992
EPIDEMIOLOGY

Evidence indicates that early life events and conditions, possibly extending to the intrauterine stages of life, and including energy restriction in early life, affect the risk of breast cancer. The mechanism of this effect is likely to be through a reduction in mammary gland mass and, inferentially, the total number of ductal stem cells. The evidence derives from epidemiologic and animal studies. It can explain certain epidemiologic findings that cannot be accounted for by more established breast cancer risk factors, including the more frequent occurrence of breast cancer in the left breast and the higher incidence of this disease among caucasian women than among Asian women in Asia.

Breast size, handedness and breast cancer risk

Article

Feb 1991
EUR J CANCER

Bra cup size and handedness were studied as possible risk factors for breast cancer. Data for 3918 cases and 11,712 controls from 7 centres were used to examine the association of handedness with laterality of breast cancer; data for 2325 cases and 7008 controls from 4 centres were used to assess the relation of bra cup size to breast cancer risk. There was a suggestive (P about 0.10) association of handedness with breast cancer laterality: odds ratio of a left-handed (or ambidextrous) woman having a left-sided cancer 1.22 (95% CI 0.96-1.56). Handedness may affect the lateral occurrence of breast cancer, although this tumour is in general more common in the left breast, possibly because this breast is usually slightly larger. Premenopausal women who do not wear bras had half the risk of breast cancer compared with bra users (P about 0.09), possibly because they are thinner and likely to have smaller breasts. Among bra users, larger cup size was associated with an increased risk of breast cancer (P about 0.026), although the association was found only among postmenopausal women and was accounted for, in part, by obesity. These data suggest that bra cup size (and conceivably mammary gland size) may be a risk factor for breast cancer.

A factor analysis of garment measures of Dutch women

Article

Oct 1968

S G Vandenberg

Breast size and mammographic pattern in relation to breast cancer risk

Article

Mar 1996
EUR J CANCER PREV

The relation of Wolfe's parenchymal patterns and radiographically-assessed breast size with breast cancer risk was evaluated in a population-based nested case-control study in Uppsala, Sweden. All women who attended a mammographic screening programme in Uppsala county starting in 1988 have been followed for the occurrence of breast cancer through 1993. The analysis was based on 295 cases and 589 age-matched controls, whose mammograms were blindly evaluated for parenchymal pattern and breast size. Women with P2 or DY pattern had a significantly elevated risk of breast cancer compared with women with N1 or P1 (OR = 2.09; 95% CI = 1.52-2.86). There was an inverse association of breast size with breast cancer risk, which disappeared after adjusting for parenchymal pattern, because breasts of smaller size tended to have high-risk parenchymal patterns. It is concluded that in Swedish women, and perhaps in Caucasian women in general, small breast size is associated with increasing breast risk through its association with high-risk parenchymal pattern. This is in contrast to the fact that Asian women, who in general have breasts of smaller size, have low prevalence of high-risk parenchymal pattern as well as low rates of breast cancer.

Genetic and nutritional modulation of colon cancer development

Article

Jan 1997
EUR J CANCER PREV

M Lipkin

The relation of Wolfe's parenchymal patterns and radiographically-assessed breast size with breast cancer risk was evaluated in a population-based nested case-control study in Uppsala, Sweden. All women who attended a mammographic screening programme in Uppsala county starting in 1988 have been followed for the occurrence of breast cancer through 1993. The analysis was based on 295 cases and 589 age-matched controls, whose mammograms were blindly evaluated for parenchymal pattern and breast size. Women with P2 or DY pattern had a significantly elevated risk of breast cancer compared with women with N1 or P1 (OR = 2.09 ; 95% Cl = 1.52-2.86). There was an inverse association of breast size with breast cancer risk, which disappeared after adjusting for parenchymal pattern, because breasts of smaller size tended to have high-risk parenchymal patterns. It is concluded that in Swedish women, and perhaps in Caucasian women in general, small breast size is associated with increasing breast risk through its association with high-risk parenchymal pattern. This is in contrast to the fact that Asian women, who in general have breasts of smaller size, have low prevalence of high-risk parenchymal pattern as well as low rates of breast cancer.

Characteristics of interview refusers: Women who decline to participate in interviews relating to eating

Article

Aug 1997

The aim of this study was to compare the eating habits and weight ranges of 27 women who refused to participate in a semistructured interview on eating with 25 women who agreed to participate, to determine if there were any systematic differences between the two groups. The women had previously completed a general psychiatric interview that also included a lifetime DSM-III-R diagnosis of eating disorders. About 2 years after this interview, the women were asked to participate in an interview that would specifically examine eating behaviors. In contrast to the results of previous studies, this study found that there was no difference between women who refused or agreed to participate in an interview about eating, in terms of their eating problems or weight ranges. It seems that eating or weight problems need not be overrepresented in groups who refuse to participate in surveys about eating, thereby undermining the accuracy of prevalence rates in the general population. Suggestions for achieving this representation are discussed.

Mammographic densities and breast cancer risk

Article

Jan 1999

The radiological appearance of the female breast varies among individuals because of differences in the relative amounts and X-ray attenuation characteristics of fat and epithelial and stromal tissues. Fat is radiolucent and appears dark on a mammogram, and epithelium and stroma are radiodense and appear light. We review here the evidence that these variations, known as mammographic parenchymal patterns, are related to risk of breast cancer. Studies that used quantitative measurement to classify mammographic patterns have consistently found that women with dense tissue in more than 60-75% of the breast are at four to six times greater risk of breast cancer than those with no densities. These risk estimates are independent of the effects of other risk factors and have been shown to persist over at least 10 years of follow up. Estimates of attributable risk suggest that this risk factor may account for as many as 30% of breast cancer cases. Mammographically dense breast tissue is associated both with epithelial proliferation and with stromal fibrosis. The relationship between these histological features and risk of breast cancer may by explained by the known actions of growth factors that are thought to play important roles in breast development and carcinogenesis. Mammographically dense tissue differs from most other breast cancer risk factors in the strength of the associated relative and attributable risks for breast cancer, and because it can be changed by hormonal and dietary interventions. This risk factor may be most useful as a means of investigating the etiology of breast cancer and of testing hypotheses about potential preventive strategies.

Prevalence and Long-Term Course of Lifetime Eating Disorders in an Adult Australian Twin Cohort

Article

Mar 2006

Few studies exist that have examined the spectrum and natural long-term course of eating disturbance in the community. We examine the lifetime prevalence and long-term course of anorexia nervosa (AN), bulimia nervosa (BN) and eating disorder not otherwise specified (EDNOS) in an adult female twin population. Female twins (n = 1002) from the Australian Twin Registry, aged 28-39 years, were assessed using the Eating Disorder Examination, revised to yield lifetime diagnostic information. For women with lifetime eating disorders, the assessment occurred, on average, 14.52 years (SD = 5.65) after onset of their disorder. In accordance with other community studies, we found a 1.9% lifetime prevalence of AN, with an additional 2.4% who met the criteria for 'partial AN' (absence of amenorrhea). Criteria for BN were met by 2.9% of the women, an additional 2.9% of women met criteria for binge eating disorder, while 5.3% met criteria for purging disorder unaccompanied by binge eating (EDNOS-p). Eleven (7%) of the women with lifetime eating disorders had a current eating disorder. Each diagnostic group continued to be differentiated by current eating pathology from women without lifetime eating disorders. Although approximately 75% of the women had a good outcome, less than 50% of each diagnostic group was asymptomatic. Eating disorders tend to improve over time often reaching subdiagnostic levels of severity, but only a minority of sufferers becomes asymptomatic. The DSM-IV diagnosis EDNOS needs to be considered in studies of the prevalence and course of eating disorders.

A Transdiagnostic Approach to Understanding Eating Disorders

Article

Aug 2006

Categorical models dominate the eating disorder field, but the tandem use of categorical and dimensional models has been proposed. A transdiagnostic dimensional model, number of lifetime eating disorder behaviors (LEDB), was examined with respect to (1) its relationship to a variety of indicators of the individual's functioning, (2) the degree to which it was influenced by genetic and environmental risk factors, and (3) exposure to specific environmental risk factors. Data from self-report and interview from 1002 female twins (mean age = 34.91 years, SD = 2.09) were examined. While 15.4% women met criteria for a lifetime eating disorder, 29% had at least one LEDB. The dimensional measure provided an indicator of associated functioning, and was influenced primarily by the nonshared environment. The number of LEDB was associated with the degree of impaired functioning. This impairment was associated with conflict between parents and criticism from parents when growing up.

Use of Latent Profile Analysis to Identify Eating Disorder Phenotypes in an Adult Australian Twin Cohort

Article

Jan 2007
ARCH GEN PSYCHIAT

The relationships among the different eating disorders that exist in the community are poorly understood, especially for residual disorders in which bingeing or purging occurs in the absence of other behaviors. To examine a community sample for the number of mutually exclusive weight and eating profiles. Data regarding lifetime eating disorder symptoms and weight range were submitted to a latent profile analysis. Profiles were compared regarding personality, current eating and weight, retrospectively reported life events, and lifetime depressive psychopathology. Longitudinal study among female twins from the Australian Twin Registry in whom eating was assessed by a telephone interview. A community sample of 1002 twins (individuals) who had participated in earlier waves of data collection. Number and clinical character of latent profiles. The best fit was a 5-profile solution with women who were (1) of normal weight with few lifetime eating disorders (4.3%), (2) overweight (10.6% had a lifetime eating disorder), (3) underweight and generally had no eating disorders except for 5.3% who had restricting anorexia nervosa, (4) of low to normal weight (89.0% had a lifetime eating disorder), and (5) obese (37.0% had a lifetime eating disorder). Each profile contained more than 1 type of lifetime eating disorder except for the third profile. Women in the first and third profiles had the best functioning, with women in the fourth and fifth profiles having similarly poorer functioning. The women in the fourth group had a symptom profile distinctive from the other 4 groups in terms of severity; they were also more likely to have had lifetime major depression and suicidality. Lifetime weight ranges and the severity of eating disorder symptoms affected clustering more than the type of eating disorder symptom.

Genes, culture and personality: An empirical approach

Jan 1989

L J Eaves
H J Eysenck
N G Martin
R Jardine
A C Heath
L Feingold
P A Young
K S Kendler

Eaves, L. J., Eysenck, H. J., Martin, N. G., Jardine, R., Heath, A. C., Feingold, L., Young, P. A., & Kendler, K. S. (1989). Genes, culture and personality: An empirical approach. Oxford: Oxford University Press.

Prelis 2: User's Reference Guide

K G Joreskog
D Sorbom

Joreskög, K. G., & Sörbom, D. (1996). Prelis 2: User's Reference Guide. Chicago, Il: Scientific Software International.

Jan 2006
121

Wade T. D.

Body Mass Index and Breast Size in Women: Same or Different Genes?

Abstract

No full-text available

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