Aging, androgens, and the metabolic syndrome in a longitudinal study of aging

Based on Adult Treatment Panel III criteria, we previously reported that the prevalence of the metabolic syndrome (MS) increased with aging; was higher if elevated 2-h plasma postglucose challenge values were included as a criterion; and was greater in men, compared with women. The aim of this study was to evaluate the relationship between the MS and circulating androgen levels in a cohort of men in the Baltimore Longitudinal Study of Aging.

Study participants were Caucasian community-dwelling adult men in the Baltimore Longitudinal Study of Aging, who underwent a fasting 2-h oral glucose tolerance test and had serum concentrations of total testosterone (T), dehydroepiandrosterone sulfate, and SHBG levels measured. The prevalence of the MS was 4, 21, 21, and 18% for men between the ages of 20 and 39, 40 and 59, 60 and 79, and 80 and 94 yr, respectively. Total T and SHBG were inversely related to the development of the MS over a mean follow-up period of 5.8 yr (range 1.5-14.0 yr), whereas the free T index and body mass index were positively related to the incidence of the MS. Age alone did not predict the development of the MS, nor did the inclusion of abnormal 2-h plasma postglucose challenge levels in the classification of the MS. Stepwise proportional hazards regression analyses showed that among the various measurements, SHBG levels exerted the greatest influence on development of the MS.

The prevalence of the MS increased with aging, and this was associated with lower androgen levels. Lower total T and SHBG predicted a higher incidence of the MS.