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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.

In an effort to better understand the relationship existing between lipoprotein pattern and longevity, we studied the lipid and lipoprotein distribution of 94 men over age 80 who lived in a nursing home, and assessed the role of selective mortality, body mass and sex hormone secretion in determining these distributions. High density lipoprotein subfraction and serum testosterone measurements were obtained on subsamples. The main findings were: (a) Presence of a lipoprotein pattern characterized by low LDL (total serum cholesterol: 179.6 +/- 36.0 mg/dl; LDL cholesterol: 106.3 +/- 31.2 mg/dl) and high HDL2 cholesterol (18.5 +/- 10.2 mg/dl) levels. (b) Occurrence of a positive association between LDL and HDL3 (r = 0.51, P less than 0.01), resulting in an overall high HDL2/HDL3 ratio. Mortality over a 6-month period was directly related to LDL level and possibly inversely related to HDL2 level, suggesting that selective mortality played a major role in determining the pattern observed. Body mass and serum testosterone concentration, which tended to be low, were independently correlated with lipoprotein level; a particularly strong correlation (positive) existed between free testosterone and triglyceride (r = 0.68, P less than 0.01). The latter results suggest that changes related to senescence also influenced lipid and lipoprotein levels.