The Contribution of Endogenous and Exogenous Factors to Male Alopecia: A Study of Identical Twins

and Dallas, Texas From the Department of Plastic Surgery, University Hospitals Case Medical Center, Case Western Reserve University School of Medicine, and the Department of Plastic Surgery, University of Texas Southwestern Medical Center.
Plastic and Reconstructive Surgery (Impact Factor: 2.99). 05/2013; 131(5):794e-801e. DOI: 10.1097/PRS.0b013e3182865ca9
Source: PubMed


: The purpose of this study was to investigate the potential contribution of environmental factors and testosterone on male alopecia.
: Ninety-two identical male twins were recruited from 2009 to 2011. A comprehensive questionnaire was completed followed by the acquisition of sputum samples for testosterone analysis and standardized digital photography. Frontal, temporal, and vertex hair loss was assessed from these photographs. Hair loss was then correlated with survey responses and testosterone levels between twin pairs. Two independent, blinded observers also rated the photographs for hair thinning.
: Increased smoking duration (p < 0.001) and the presence of dandruff (p = 0.028) were significantly associated with increased frontal hair loss. Increased exercise duration (p = 0.002), consumption of more than four alcoholic drinks per week (p = 0.042), and increased money spent on hair loss products (p = 0.050) were all associated with increased temporal hair loss. Daily hat use (p = 0.050), higher body mass index (p = 0.012), and higher testosterone levels (p = 0.040) were associated with decreased temporal hair loss. Factors that were significantly associated with increased vertex hair loss included abstinence from alcohol consumption (p = 0.030), consumption of more than four alcoholic drinks per week (p = 0.004), increased smoking duration (p = 0.047), increased exercise duration (p = 0.050), and increased stress duration (p = 0.010). Lower body mass index, more children, increased caffeine consumption, history of skin disease, and abstinence from alcohol were significantly associated with increased hair thinning scores (p < 0.05).
: This study offers substantial evidence that exogenous factors may have a clinically significant impact on hair loss.
: Risk, III.

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    ABSTRACT: Current literature provides little information about the impact of environmental exposures on the severity of acquired blepharoptosis. The authors assessed environmental factors that may contribute to eyelid ptosis in a population of identical twins. Photographs of 286 sets of twins from a prospectively collected database from 2008 to 2010 were reviewed. The authors identified 96 sets of identical twins (192 individual persons) who had differing severity of ptosis. Digital photographs were analyzed, and the degree of ptosis was measured in each eye of every subject. The external factors that could potentially contribute to blepharoptosis were taken into consideration. The authors then assessed the correlations of 9 different environmental risk factors with ptosis. Generalized linear mixed model were constructed to determine the associations of ptosis measurements with environmental risk factors obtained from the subject survey database. The mean level of upper eyelid ptosis in the study population was 1.1 mm. The mean difference in ptosis between twins was 0.5 mm. Wearing contact lenses, either hard or soft, was significantly associated with ptosis. The mean ptosis measurement among twins who did not wear contact lenses was 1.0 mm; for those who wore soft contact lenses, the mean was 1.41 mm, and for those who wore hard contact lenses, the mean was 1.84 mm. Acquired ptosis is not linked to body mass index, smoking behavior, sun exposure, alcohol use, work stress, or sleep. Wearing either hard or soft lenses was associated with an increased risk of ptosis. These influences are independent of genetic predisposition. 3 Diagnostic. © 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission:
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