Date of Graduation

Winter 12-16-2016

Document Type

Project

Degree Name

Master of Public Health (MPH)

College/School

School of Nursing and Health Professions

First Advisor

Dru Bhattacharya

Abstract

Vitamin D and calcium have received increased attention for their potential roles in improving cardiovascular health. The active form of vitamin D, 1,25-hydroxyvitamin D (25[OH]D), may influence blood pressure by increasing gastrointestinal calcium absorption. The objectives of this study were to first examine the association between blood pressure and blood serum 25(OH)D levels, and then explore the interaction between 25(OH)D, calcium intake, and blood pressure. Cross-sectional analysis featured 24,844 U.S. adults aged 20-80 years from three cycles of the National Health and Examination Survey (NHANES 2001-2006). Linear regression models were used to determine the adjusted association of 25(OH)D categories with blood pressure. An interaction term between 25(OH)D and calcium intake was fitted in the fully adjusted regression model. All analyses accounted for the complex survey design. The mean age was 37.5 (0.3) and 48.6% of participants were male. Mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) in mmHg were 120.3 (0.3) and 69.3 (0.2), respectively. Linear regression models showed that SBP, but not DBP, was negatively and significantly associated with increasing 25(OH)D levels. Moreover, a significant interaction between 25(OH)D and calcium intake levels was noted for DBP (P=0.040). Conclusively, the association between 25(OH)D levels and DBP may differ by calcium intake in the U.S. population.

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