Vasectomy, cigarette smoking, and age at first sexual intercourse as risk factors for prostate cancer in middle-aged men

Br J Cancer. 1988 Mar;57(3):326-31. doi: 10.1038/bjc.1988.74.

Abstract

A population-based case-control study was conducted in men aged 60 or less to assess the risk of prostate cancer associated with vasectomy and other factors. Data were obtained from 216 case-control pairs by telephone interviews; this number represented 55% of all eligible cases. The matched pairs relative risk (RR) for vasectomy in ever married men was 1.4 with a 95% confidence interval (CI) of 0.9-2.3. There was a positive association between the number of years since vasectomy and prostate cancer risk (1-sided P = 0.01). Early age at first sexual intercourse was associated with increased prostate cancer risk (age less than 17 vs. 21+, RR = 2.3, 95% CI = 1.3, 4.0) but there were no consistent associations with number of sexual partners or frequency of sexual intercourse. Cigarette smoking was also associated with increased risk of prostate cancer (RR = 1.9, 95% CI = 1.2, 3.0) and there was a positive dose-response relationship with years of smoking (1-sided P = 0.001). We discuss the possible implication of the low response rate on each of these findings. To determine whether the association with vasectomy might have a hormonal basis, we compared levels of testosterone (T) and testosterone binding globulin-binding capacity (TeBG-bc) in 33 of the vasectomized control men with levels in 33 non-vasectomized controls of the same age, weight and height. T levels were higher in vasectomized than in non-vasectomized controls (1-sided P = 0.06). The ratio of T to TeBG-bc (an index of bioavailable T) was 13.5% higher in vasectomized men (1-sided P = 0.03).

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenocarcinoma / blood
  • Adenocarcinoma / etiology*
  • Age Factors
  • Coitus*
  • Humans
  • Male
  • Middle Aged
  • Prostatic Neoplasms / blood
  • Prostatic Neoplasms / etiology*
  • Risk Factors
  • Sex Hormone-Binding Globulin / metabolism
  • Smoking / adverse effects*
  • Testosterone / blood
  • Vasectomy*

Substances

  • Sex Hormone-Binding Globulin
  • Testosterone