have investigated the effect of smoking on plasma sex hormones in men (testosterone,
estradiol, estrone, androstenedione and dehydroepiandrosterone sulphate) but have produced
inconsistent results. Hence it is unclear whether smoking is anti-estrogenic in males. 11
prospective studies have measured hormone levels before the onset of prostate cancer but
most have found no significant difference in serum testosterone or dihydrotestosterone
levels between prostate cancer cases and controls.