Abstract 12271: Association of Sex Hormone Status with Circulating Natriuretic Peptides
Introduction: Natriuretic peptides (NP) have cardioprotective effects and circulate at higher concentrations in women than men. The mechanisms for these sex-related differences in circulating levels and the impact of hormone therapy are unclear. Experimental studies suggest that androgens may suppress NP secretion.
Hypothesis: We hypothesized that higher free testosterone (FT), in men vs women or in the absence vs presence of hormone therapy in women, is associated with lower plasma N-terminal proB-type NP (BNP).
Methods: We studied 4056 men and women (age 40±9 y) from the Framingham Heart Study Third Generation cohort. Sex hormone status was grouped as: men, pre-/post-menopausal women without hormone therapy, postmenopausal women on hormone therapy and premenopausal women on oral contraceptives. BNP was measured by a standard immunoassay, total testosterone by liquid chromatography tandem mass spectrometry, and sex hormone binding globulin (SHBG) by an immunofluorometric assay. FT was calculated from the law of mass action equations. Groups were compared by analysis of covariance with Bonferroni correction.
Results: Circulating BNP was related to sex hormone status (Figure; overall p <0.0001). Men had lower BNP than women regardless of menstrual status or hormone therapy, and women on oral contraceptives had higher BNP than women without hormone therapy (all p<0.0001). These relations remained significant after adjusting for age, body mass index and cardiovascular risk factors. Higher FT was associated with lower BNP in men (r=−0.14, p=0.007) and women (r=−0.26, p<0.0001). SHBG was positively related to BNP in men (r=0.31, p<0.0001) and women (r=0.32, p<0.0001).
Conclusions: Circulating BNP is related to sex and hormone therapy. Differences in testosterone and SHBG levels may explain, at least partly, the sex differences in BNP levels. The implications of these findings for sex-related differences in cardiovascular risk deserve further study.
- © 2010 by American Heart Association, Inc.