Birth weight and early socio‐economic disadvantage as predictors of sex hormones and sex hormone binding globulin in men at age 49–51 years

Abstract

A number of associations have been shown between early growth and later sex hormone levels in women, but less is known about this relationship in men. This study investigated life-course predictors of sex hormones in men in the Newcastle Thousand Families birth cohort. The Newcastle Thousand Families Study is a prospective study initiated in 1947. At age 49-51 years, 574 study members returned detailed self-completion questionnaires and 412 attended for clinical examination, including 172 men in whom blood samples were taken. Estradiol, follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and sex hormone binding globulin (SHBG) were measured. Free testosterone concentrations were also calculated. Social class at birth independently predicted FSH and LH, with higher levels with increasing socioeconomic disadvantage. SHBG was higher with increasing standardized birth weight and lower with increasing contemporary body mass index (BMI). BMI also predicted LH, SHBG, and testosterone. None of the variables included within this analysis were significant predictors of estradiol. No other associations were seen with any of the variables included from across the life-course. Our findings suggest that birth weight may be positively associated with SHBG and early socioeconomic status may be related to FSH and LH in men. These novel findings are independent of contemporary BMI. Given the links between sex hormones, SHBG and disease outcomes such as type II diabetes and osteoporosis, it is possible that sex hormones may play a mediating role in the associations between circumstances in early life and later risk of chronic disease.