Associations Between Vitamin D Biomarkers and Cardiometabolic Outcomes Among Women

Abstract

There is growing evidence that vitamin D endocrine system may be associated with multiple cardiometabolic outcomes, such as gestational diabetes mellitus (GDM), type 2 diabetes, and other relevant cardiometabolic comorbidities, as well as some intermediate cardiometabolic biomarkers. African Americans tend to have lower 25-hydroxyvitamin D[25(OH)D] levels and higher cardiometabolic risk than whites. However, the temporal relation between vitamin D status and cardiometabolic outcomes remains unclear due to the lack of longitudinal data. Further, whether adding information on parathyroid hormone (PTH) can explain black-white disparities in cardiometabolic health is unknown. In this dissertation, I first prospectively and longitudinally investigated vitamin D status during early to mid-pregnancy in relation to GDM risk in a multiracial cohort of women from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Fetal Growth Studies-Singleton cohort. I also analyzed the data from the Women’s Health Initiative-Observational Study to 1) cross-sectionally examine race (black-white)-specific linear and non-linear relations of 25(OH)D and PTH with a panel of cardiometabolic biomarkers, including high-sensitive C-reactive protein, estimated glomerular filtration rate, and homeostatic model assessment of insulin resistance and beta-cell function, and 2) cross-sectionally and prospectively evaluate the combined associations of 25(OH)D and PTH with risk of diabetes and related cardiometabolic comorbidities (obesity, hypertension, chronic kidney disease, and cardiovascular disease) in U.S. white and black postmenopausal women. This research provides evidence of the temporal association between vitamin D status and cardiometabolic risk among women from racially/ethnically diverse groups, and possible black-white differences in these associations. The findings enhance our understanding of the contribution of vitamin D-PTH endocrine system to racial disparities in cardiometabolic health.