Low serum testosterone in men is inversely associated with non-fasting serum triglycerides: the Tromsø study

To study the relationships between endogenous testosterone, sex hormone-binding globulin (SHBG) and serum lipids in non-fasting men.

We performed a cross-sectional study in 1274 men without known cardiovascular disease who participated in a population-based study, the 1994/1995 Tromsø study. Anthropometric characteristics were measured and questionnaires regarding lifestyle and medical history were completed. Non-fasting blood samples were drawn between 08.00 and 16.00h, and total testosterone, SHBG, triglycerides (TG), total cholesterol (TC) and high-density lipoprotein (HDL) were analyzed.

In stratified analyses based on sampling time, a linear increase in serum TG levels was found in men with total testosterone levels below the 50th percentile during the day (p for trend=0.004). In contrast, serum triglycerides did not change during the day in men with testosterone levels above the 50th percentile. In regression analyses, total testosterone and SHBG were inversely and independently associated with TG (p<0.001 and p<0.001 respectively), and positively and independently associated with HDL (p=0.005 and p<0.001, respectively). Men with an unfavorable lipid profile (HDL <0.90 and TG >1.8) had significantly lower levels of total testosterone and SHBG (p=0.004 and p<0.001, respectively) in age and BMI adjusted analyses, compared to men with a normal lipid profile.

Low serum total testosterone was associated with a linear increase in serum TG during the day, and was independently associated with an unfavorable lipid profile. Our findings may indicate that low total testosterone is associated with impaired TG metabolism in men.