Sex hormone-binding globulin and lipid profile in pubertal children

Men and women have different lipid profiles throughout life, related to changes in sex hormones; and this has been associated with sex-related differences in the prevalence of coronary heart disease. The influence of sex hormone changes during puberty on the lipid profile has been reported, but levels of sex hormone-binding globulin (SHBG) (the specific plasma binding protein of sex hormones) have not been evaluated even though its regulatory role might be crucial. The aim of this study was to analyze the relationship between sex hormones and SHBG and changes in plasma lipid levels during puberty. Our population-based sample included 370 healthy schoolchildren (175 male and 195 female), ranging from 12 to 15 years old. High-density lipoprotein cholesterol (HDL-C) levels were significantly lower in 15-year-olds than in younger boys, and apolipoprotein (apo) A-I levels steeply decreased across the studied age groups. Parallel to these changes, testosterone levels increased whereas SHBG decreased as age increases in boys. In girls, no significant differences were observed in these variables among the age groups. Testosterone and SHBG were highly correlated with anthropometric variables. Sex hormone-binding globulin was negatively associated with triglycerides (TG) in both sexes, remaining statistically significant after further adjustment for age and body mass index (BMI) in girls. Sex hormone-binding globulin was the only predictive variable for HDL-C and TG in multiple linear regression analysis, after adjustment by BMI, in both sexes, accounting for 10% of the variance of HDL-C in boys and for around 5% of the variance of TG in both sexes. In boys, testosterone and SHBG remained significantly correlated to apo A-I levels, even after adjusting for age and BMI, and were the most important predictive variables for apo A-I in multiple linear regression analysis. In conclusion, SHBG levels are related to a decrease in HDL-C and apo A-I levels during puberty in boys and to a decrease in TG levels during puberty in both sexes.