Associations Among Androgens, Estrogens, and Natriuretic Peptides in Young Women Observations From the Dallas Heart Study

ObjectivesWe sought to determine if natriuretic peptides are associated with estrogen and androgen status in a population study of young women without known cardiac disease.BackgroundCirculating concentrations of plasma B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) are higher in women than in men, and they may be influenced by estrogens and androgens.MethodsCardiac magnetic resonance imaging, dual energy X-ray absorbtiometry, and measurements of BNP, NT-proBNP, follicle-stimulating hormone (FSH), total testosterone, and sex hormone-binding globulin (SHBG), were performed in 682 women (ages 35 to 49 years) participating in the Dallas Heart Study.ResultsIn multivariable analyses adjusting for age, race/ethnicity, body mass index (BMI), serum creatinine, left ventricular mass and left ventricular ejection fraction <55%, menopausal status, and FSH were not associated with BNP and NT-proBNP. In contrast, higher SHBG was associated with higher BNP and NT-proBNP, while the free androgen index and calculated free testosterone were inversely associated with BNP and NT-proBNP (p < 0.0001 for each). Addition of SHBG or any measure of free testosterone to the multivariable models modified the effect of BMI and lean mass, such that measures of body composition were no longer significantly associated with BNP or NT-proBNP.ConclusionsAmong young women, measures of free testosterone were independently and inversely associated with BNP and NT-proBNP. These results suggest that circulating free testosterone, not estradiol, mediates gender differences in natriuretic peptides. In addition, the association between higher BMI and lean body mass with natriuretic peptides may be mediated by testosterone

Race and Gender Differences in C-Reactive Protein Levels

ObjectivesThis study sought to determine whether there are race and gender differences in the distribution of C-reactive protein (CRP) levels.BackgroundFew data are available comparing CRP distributions in different race and gender groups. Recent clinical practice recommendations for CRP testing for cardiovascular risk assessment suggest a uniform threshold to define high relative risk (>3 mg/l).MethodsWe measured CRP in 2,749 white and black subjects ages 30 to 65 participating in the Dallas Heart Study, a multiethnic, population-based, probability sample, and compared levels of CRP between different race and gender groups.ResultsBlack subjects had higher CRP levels than white subjects (median, 3.0 vs. 2.3 mg/l; p < 0.001) and women had higher CRP levels than men (median, 3.3 vs. 1.8 mg/l; p < 0.001). The sample-weight adjusted proportion of subjects with CRP levels >3 mg/l was 31%, 40%, 51%, and 58% in white men, black men, white women, and black women, respectively (p < 0.05 for each group vs. white men). After adjustment for traditional cardiovascular risk factors, estrogen and statin use, and body mass index, a CRP level >3 mg/l remained more common in white women (odds ratio [OR] 1.6; 95% confidence interval [CI] 1.1 to 2.5) and black women (OR 1.7; 95% CI 1.2 to 2.6) but not in black men (OR, 1.3; 95% CI, 0.8 to 1.9) when compared with white men.ConclusionsSignificant race and gender differences exist in the population distribution of CRP. Further research is needed to determine whether race and gender differences in CRP levels contribute to differences in cardiovascular outcomes, and whether thresholds for cardiovascular risk assessment should be adjusted for different race and gender groups