title: Second to fourth digit ratio (2D:4D) and prostate cancer risk in the Melbourne Collaborative Cohort Study.
abstract: BACKGROUND
  The ratio of the lengths of index and ring fingers (2D:4D) is a marker of prenatal exposure to sex hormones, with low 2D:4D being indicative of high prenatal androgen action. Recent studies have reported a strong association between 2D:4D and risk of prostate cancer.
  
  
  METHODS
  A total of 6258 men participating in the Melbourne Collaborative Cohort Study had 2D:4D assessed. Of these men, we identified 686 incident prostate cancer cases. Hazard ratios (HRs) and confidence intervals (CIs) were estimated for a standard deviation increase in 2D:4D.
  
  
  RESULTS
  No association was observed between 2D:4D and prostate cancer risk overall (HRs 1.00; 95% CIs, 0.92-1.08 for right, 0.93-1.08 for left). We observed a weak inverse association between 2D:4D and risk of prostate cancer for age <60, however 95% CIs included unity for all observed ages.
  
  
  CONCLUSIONS
  Our results are not consistent with an association between 2D:4D and overall prostate cancer risk, but we cannot exclude a weak inverse association between 2D:4D and early onset prostate cancer risk.
authors: Cancer Epidemiology Centre, Cancer Council of Victoria, Melbourne, Victoria, Australia. David.Muller@cancervic.org.au
authors: D C
authors: DC
authors: Muller
authors: G G
authors: GG
authors: Giles
authors: J T
authors: JT
authors: Manning
authors: J L
authors: JL
authors: Hopper
authors: D R
authors: DR
authors: English
authors: G
authors: G
authors: Severi
mesh_terms: D000368:Aged; D015331:Cohort Studies; D005385:Fingers / Q000033:anatomy & histology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D012307:Risk Factors