Vitamin D and blood pressure control among hypertensive adults: results from NHANES 2001-2014.

Abstract

Observational evidence supports an inverse association between hypovitaminosis D and blood pressure (BP), but intervention data have failed to demonstrate beneficial effects of vitamin D supplementation on BP. Following the downwards redefinition of hypertension treatment targets and the need to better identify individuals at greater risk for uncontrolled BP, our aim was to test the association of serum vitamin D levels with the definition of uncontrolled BP according to European guidelines in treated hypertensive adults. We retrospectively analyzed cross-sectional, nationally representative data from treated hypertensive adults aged at least 18 years with available serum 25 (OH)D measurements. BP was examined as continuous (mmHg) and categorical (at or above treatment goal, as recommended by guidelines) variable; BP means and odds ratios for uncontrolled BP according to vitamin D levels were calculated using progressively adjusted models. Treated hypertensive adults with vitamin D deficiency had higher mean BP (+2.4/3.5 mmHg; P < 0.01) and 25-29% higher risk of uncontrolled BP compared to those with vitamin levels at least 75 nmol/l. These results were confirmed across age, sex, and racial/ethnic strata. Vitamin D insufficiency was associated with higher BP by 0.5/2.4 mmHg, but not with an increased risk of uncontrolled hypertension. 25 (OH)D levels might indicate host-specific features related to poor BP control. The attempt to use a biomarker of exposure as an indicator of need for treatment risks to be misleading.