Low Sex Hormone-Binding Globulin, Total Testosterone, and Symptomatic Androgen Deficiency Are Associated with Development of the Metabolic Syndrome in Nonobese Men

Abstract

The metabolic syndrome (MetS), characterized by central obesity, lipid and insulin dysregulation, and hypertension, is a precursor state for cardiovascular disease. The purpose of this analysis was to determine whether low serum sex hormone levels or clinical androgen deficiency (AD) predict the development of MetS. Data were obtained from the Massachusetts Male Aging Study, a population-based prospective cohort of 1709 men observed at three time points (T1, 1987-1989; T2, 1995-1997; T3, 2002-2004). MetS was defined using a modification of the ATP III guidelines. Clinical AD was defined using a combination of testosterone levels and clinical signs and symptoms. The association between MetS and sex hormone levels or clinical AD was assessed using relative risks (RR), and 95% confidence intervals (95% CI) were estimated using Poisson regression models. Analysis was conducted in 950 men without MetS at T1. Lower levels of total testosterone and SHBG were predictive of MetS, particularly among men with a body mass index (BMI) below 25 kg/m2 with adjusted RRs for a decrease in 1 sd of 1.41 (95% CI, 1.06-1.87) and 1.65 (95% CI, 1.12-2.42). Results were similar for the AD and MetS association, with RRs of 2.51 (95% CI, 1.12-5.65) among men with a BMI less than 25 compared with an RR of 1.22 (95% CI, 0.66-2.24) in men with a BMI of 25 or greater. Low serum SHBG, low total testosterone, and clinical AD are associated with increased risk of developing MetS over time, particularly in nonoverweight, middle-aged men (BMI, <25). Together, these results suggest that low SHBG and/or AD may provide early warning signs for cardiovascular risk and an opportunity for early intervention in nonobese men.