Reference intervals for serum sex hormones in Han Chinese adult men from the Fangchenggang Area Male Health and Examination Survey.

Abstract

The aim was to establish reference intervals for serum sex hormones in adult men in the Fangchenggang area of China.
Serum samples from 1,191 healthy male subjects, aged 20 - 69 years, were collected from the Fangchenggang Area Male Health and Examination Survey (FAMHES). Total testosterone (T), estrogen (E2), luteinising hormone (LH), follicle-stimulating hormone (FSH), and sex hormone-binding globulin (SHBG) were measured by electrochemiluminescence immunoassay (Elecsys). Free testosterone (FTc) was calculated from the concentrations of T, SHBG, and albumin.
The total nonparametric reference intervals for male sex hormones in our study were 12.6 - 37.0 nmol/L for T, 0.24 - 0.69 nmol/L for FTc, 65.4 - 207.7 pmol/L for E2, 2.2 - 11.6 IU/L for LH, 1.8 - 16.5 IU/L for FSH, and 18.2 - 95.1 nmol/L for SHBG. Age had a significant positive association with LH (r = 0.218), FSH (r = 0.427), and SHBG (r = 0.427) and a negative association with FTc (r = -0.383) and E2 (r = -0.098), but no significant association with T after adjustment for BMI. The age-dependent reference intervals were also calculated. Higher T and FTc concentrations were found in men who smoke compared with non-smokers, while no significant differences were found in E2, LH, FSH, and SHBG. When stratified for the number of cigarettes smoked per day, we found that the distributions of serum T levels were significantly higher only in the smokers who smoked 11 or more cigarettes a day than the non-smokers. Unlike T, the distributions of serum FTc levels were significantly higher only in the smokers who smoked less than 11 cigarettes a day, while the FSH levels were significantly lower.
In clinical practice, single reference intervals can be used for men aged 20 - 69 years for T and E2 measured with the Elecsys method, but separate age-dependent reference intervals should be used for FTc, LH, FSH, and SHBG. In addition, distinct reference intervals for T should be established for non-smokers or smokers (1 - 10 cigarettes/day) and smokers (> or = 11 cigarettes/day).