title: Investigation of the Association of the Second-to-Fourth Digit Ratio with Skin Sebum Levels in Females with Acne Vulgaris.
abstract: BACKGROUND
  A relationship between acne vulgaris (AV) and the masculinized (lower) second-to-fourth digit (2D:4D) ratio in females was demonstrated in our previous study. Development of the digits and the sebaceous glands both occur during the same gestational period; therefore, the association between the 2D:4D ratios and AV may result from the effects of the prenatal endocrine environment on the sebaceous glands.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the relationship between the 2D:4D ratio and sebum levels in the skin of females with AV.
  
  
  METHODS
  In total, 215 female AV patients and 92 healthy controls, aged 18-35 years, were enrolled in this study. Finger-length measurements were made using a digital Vernier caliper, and the sebum levels of five facial areas were measured using a Sebumeter SM 815. Acne severity was assessed using the International Consensus Conference on Acne Classification System.
  
  
  RESULTS
  The 2D:4D ratios of the AV patients were significantly lower than those of the controls, for both hands. The mean sebum levels in the T-zone, U-zone and whole face were significantly higher for AV patients compared with controls. The 2D:4D ratio in the left hand showed significant negative correlations with the sebum levels in the U-zone; however, no association was found between the 2D:4D ratios and sebum levels in the T-zone and whole face. While acne severity was positively correlated with skin sebum levels, no correlation between acne severity and 2D:4D ratios was observed.
  
  
  CONCLUSIONS
  This study provides preliminary evidence regarding the association between lower 2D:4D ratios and higher rates of sebum secretion in the U-zone for females with AV. The 2D:4D ratio might be a predictor of sebum levels, as well as acne development, in females.
authors.affiliation: Department of Dermatology, School of Medicine, Selcuk University, 42075, Konya, Turkey. bilgicozlem@yahoo.com.
authors.forename: Özlem
authors.initials: Ö
authors.lastname: Bilgiç
authors.affiliation: Department of Dermatology, School of Medicine, Selcuk University, 42075, Konya, Turkey.
authors.forename: Cevdet
authors.initials: C
authors.lastname: Altınyazar
authors.affiliation: Department of Dermatology, School of Medicine, Selcuk University, 42075, Konya, Turkey.
authors.forename: Hüseyin
authors.initials: H
authors.lastname: Hıra
authors.affiliation: Department of Dermatology, School of Medicine, Selcuk University, 42075, Konya, Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Doğdu
mesh_terms: D000152:Acne Vulgaris / Q000503:physiopathology*; D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D018450:Disease Progression; D005260:Female; D005385:Fingers / Q000473:pathology*; D006801:Humans; D012016:Reference Values; D012629:Sebum / Q000378:metabolism*; D012867:Skin / Q000378:metabolism; D018709:Statistics, Nonparametric; D055815:Young Adult