Vitamin D status and its correlation with blood pressure in premenopausal Saudi women: a cross-sectional study.

Abstract

Vitamin D deficiency is a major health problem in the Saudi population. A negative association between blood pressure and vitamin D level has been suggested in several clinical and epidemiological studies and evidence for an effect of vitamin D in lowering blood pressure was reported. These findings indicate that 1,25(OH)2D3 deficiency may play a role in the pathogenesis of hypertension through its effect on the renin-angiotensin system. We are the first to investigate the correlation between blood pressure or renin concentration and vitamin D status in the Saudi population METHODS: we included 201 healthy Saudi premenopausal females (20-45 years old). Blood pressure was measured by a standardized method using an automated blood pressure monitor (BPTru). Fasting blood samples were collected from each participant after 20 minutes of rest in the seated position. Serum cholicalciferol, PTH and renin concentration were measured by sandwich chemiluminescence immunoassaymethod (DiaSorin, Italy). RESULTS: The analysis included 192 subjects who were normotensive (blood pressure <140/90 mmHg). A total of 34% of women had a severe deficiency (vitamin D ≤ 12.5 nmol/L); 41% had moderate deficiency (vitamin D levels between 12.5 - 25 nmol/L); 23% had mild deficiency (vitamin D level ≥ 25 - < 50 nmol/L); and 2% had insufficiency (vitamin D level ≥ 50 - ≤ 75 nmol/L). None had a sufficient level of ≥75 nmol/L. The systolic blood pressure ranged from 79-130.5mmHg and the diastolic from 48.5-85.5 mmHg. Both systolic and diastolic blood pressures were significantly higher in women that were in the lower 2 quartiles of vitamin D. However, linear regression analysis adjusting for potential confounders showed that 25(OH)D level was not a predictor of either systolic or diastolic blood pressures. A negative correlation (although not significant) was found between vitamin D level and plasma renin concentration in this study group. CONCLUSION: Vitamin D deficiency was highly prevalent among the study group. Vitamin D was a not a predictor of either systolic or diastolic blood pressure. There was a negative correlation between vitamin D level and renin concentration although not statically significant. It is possible that any underlying relationship was obscured by the relatively young age group or due to the narrow blood pressure range of the studied population. A larger sample size including hypertensive subjects may be needed.