Abstract 814: The Association of Vitamin D With Cardiovascular Disease and Osteopenia May Be Mediated Through a Vitamin D-Sex Steroid Hormone Interaction: Results From the Third National Health and Nutrition Examination Survey (NHANES-III)
Background: Both sex steroid hormones and 25-hydroxyvitamin D [25(OH)D] levels are independently associated with bone mineral density (BMD) and cardiovascular disease (CVD) risk. Laboratory studies suggest that sex hormones and 25(OH)D may interact. Thus, we evaluated whether there is a statistical interaction between 25(OH)D levels and sex hormones on risk of osteopenia and CVD.
Methods: Testosterone (T), estradiol (E2), sex hormone binding globulin (SHBG), 25(OH)D, BMD, and prevalent CVD were measured in a sample of adult men from NHANES III (n=1010). Osteopenia was defined as 1–2.5 standard deviations below mean BMD for white men age 20 –29 years. Prevalent CVD was defined by a self-report of coronary heart disease, stroke, angina (Rose questionnaire), or measured hypertension. The joint association of sex hormones and 25(OH)D levels with the separate outcomes of osteopenia and CVD was estimated using logistic regression adjusting for age, race/ethnicity, smoking, physical activity, and percent body fat, and accounting for survey weighting. Effect modification was evaluated with the Wald test.
Results: Overall, there was no significant trend of adjusted geometric mean sex hormone levels across 25(OH)D levels. Adjusted-odds for prevalent CVD were greater among men with lower total T, free T, and T/SHBG and higher E2/T levels (all p-trend<0.01, see Table⇓ for T/SHBG), but no significant interaction with 25(OH)D was observed (p-interaction>0.05). The odds of osteopenia were greater with lower free T, T/SHBG, and E2/SHBG levels. However, odds of both osteopenia and prevalent CVD per decreasing molar ratio of E2/SHBG were greater among 25(OH)D deficient (<20 ng/ml) vs replete men (p-interaction<0.05 for both, Table⇓).
Conclusion: Vitamin D deficiency and a lower E2/SHBG ratio may interact to influence osteopenia and prevalent CVD risk in men, providing a possible mechanism for the frequently observed association between osteoporosis and atherosclerosis.