Relationships between serum testosterone, fasting insulin and lipoprotein levels among elderly men

We have previously reported the existence of an association between endogenous male sex hormone and lipoprotein levels in elderly men confined to a nursing home. In a further attempt to elucidate the significance of the association mentioned, we studied the relationship existing in that population between serum testosterone and fasting insulin levels, and between fasting insulin level and lipoprotein pattern. The data were analysed by means of stepwise multiple regression analyses. Serum testosterone and fasting insulin were found to be strongly correlated; this is consistent with the notion that androgen secretion affects directly circulating insulin level. But no independent relationship was demonstrable between fasting insulin and the three lipid-lipoprotein categories studied, namely total serum cholesterol, triglyceride and HDL-cholesterol, suggesting that in this particular population, the effect of male sex hormones upon lipoproteins is not mediated through insulin. Together, these various observations support the belief that androgen secretion affects significantly CAD risk factor levels in elderly men.