Serum vitamin D level and prehypertension among subjects free of hypertension.

BACKGROUND Low serum vitamin D levels are associated with high blood pressure (BP). Prehypertension is a preclinical stage where primary prevention efforts have been recommended for delaying or preventing the onset of hypertension. However, the majority of studies examining the association between vitamin D and BP have not accounted for kidney function or systemic inflammation. METHODS Participants of the 3rd National Health and Nutrition Examination Survey > 20 years of age and free of hypertension (n = 9,215, 53.5% women) and clinical cardiovascular disease were examined. Serum vitamin D levels were analyzed as quartiles. Prehypertension (n = 3,712) was defined as systolic BP 120-139 mm Hg or diastolic BP 80-89 mm Hg. RESULTS Lower serum vitamin D levels were found to be associated with prehypertension independent of potential confounders including body mass index (BMI), serum cholesterol, C-reactive protein and estimated glomerular filtration rate. Compared to the highest quartile of serum vitamin D (referent), the odds ratio (95% confidence interval) of prehypertension associated with the lowest quartile was 1.48 (1.16-1.90; p trend < 0.0001). This association persisted in subgroup analyses by gender, race-ethnicity and BMI. CONCLUSION Lower serum vitamin D levels are associated with prehypertension in a representative sample of US adults.