Figure 2.

Association between number of cigarettes smoked per day and serum sex hormone levels in middle-aged and elderly men. Association between number of cigarettes smoked per day and serum levels of (A) total testosterone, (B) calculated free testosterone, (C) luteinizing hormone, and (D) sex hormone-binding globulin in middle-aged and elderly men. CFT, calculated free testosterone; SHBG, sex hormone-binding globulin. Geometric mean values were calculated using multiple covariance and adjusting for age (in “overall” analysis only), body mass index, and alcohol intake. Error bars indicate standard error. *P < 0.05, ** P < 0.01, *** P < 0.001 vs. current smokers who smoked <10 cigarettes/day. Regression coefficients were obtained from multiple regression adjusting for age (in “overall” analysis only), body mass index, and alcohol intake and were calculated separately for daily cigarette consumption subgroups, which were ordinally categorized as <10, 10-20, >20 cigarettes/day. *P < 0.05, ** P < 0.01 and *** P < 0.001 for regression coefficients.