Correlation Between Plasma Lipoprotein Lp(a)and Sex Hormone Concentrations: A Cross-Sectional Study in Healthy Males

Summary

High concentrations of lipoprotein Lp(a) have been related to atherosclerotic disease, both at coronary and cerebrovascular levels. Although Lp(a) levels are under a strict genetic control, being inversely related to the molecular weight of apo(a) isoforms, an interference of endogenous sex steroids on Lp(a) metabolism has been hypothesized. The aim of this study was to investigate the interrelationship between plasma Lp(a) and sex hormone concentrations in 98 healthy males, controlled as for their nutritional status by anthropometric measurements. Statistical evaluation was performed employing simple and multiple stepwise regression analysis. No significant correlation was found between Lp(a) levels and fT, E2 and gonadotropins, while they were positively and independently related to LDL-cholesterol and DHEA-S. As for the other lipoproteins, a positive correlation between HDL-cholesterol and E2 and an inverse correlation between triglycerides and SHBG were observed. These data suggest that endogenous testosterone and estradiol do not affect Lp(a) metabolism in males, at least in physiological concentrations. However Lp(a) might be affected by DHEA-S, the most abundant product of the adrenal gland. The positive correlation of HDL-cholesterol to E2 suggests that estrogens play a major role in lipid metabolism also in males, in spite of their low concentrations; more complex to be explained is the finding of an inverse relationship between Tg and SHBG. Further studies are needed in order to clarify the influence of sex steroids on lipid metabolism, mainly on Lp(a), under physiological conditions; population samples homogeneous in terms of apo a isoforms could be the ideal objects of such studies, in order to avoid the great interindividual variability of Lp(a) concentrations.

Key words

Lp(a) - Lipoproteins - Sex Hormones - DHEA-S