A study of serum Vitamin D level and its association with hypertension.

Background: Evidence suggests that low levels of Vitamin D may adversely affect the cardiovascular (CV) system. Several studies have been done regarding the relation and possible causative role of Vitamin D in CV disorders and its well-known risk factors; however, there are limited studies in this part of the world. The aims were as follows: (1) To study the relation between serum Vitamin D level between nonhypertensive and hypertensive patients. (2) To study the relation of serum Vitamin D levels in patients with isolated systolic hypertension (ISH), isolated diastolic hypertension, systolo-diastolic hypertension, and their comparison vis-à-vis nonhypertensives.

Materials and Methods: A cross-sectional study was conducted with 154 patients attending medicine outpatient department of a tertiary care hospital of North Bengal from June 2012 to May 2013. The Vitamin D was measured by direct ELISA method. Blood pressure (BP) measurements were done. Statistical analysis was done by using SPSS 16.0 for Windows.

Results: The Vitamin D level in the hypertensive group was 22.36 ± 12.64; ISH Group was 22.04 ± 14.26; the isolated diastolic hypertension (IDH) Group was 18.82 ± 0.00; and the systolo-diastolic hypertensives (SDH) Group was 22.67 ± 12.51. Then, the mean value of Vitamin D in nonhypertensive Group (27.47 ± 13.43) was significantly ( P < 0.05) higher than IDH, SDH, and the hypertensive as a whole groups. The relation with ISH Group also reached near significance ( P = 0.074). There was a negative correlation with BP and serum Vitamin D. This remained statistically significant ( P = 0.044) for systolic BP (SBP) and near significant ( P = 0.075) for mean arterial pressure. In population having serum Vitamin D <30 ng/ml (deficient or insufficient), the negative correlation relationship between SBP and serum Vitamin D remains statistically significant ( P = 0.010).

Conclusion: Among the hypertensives, SDH shows significantly lower levels of serum Vitamin D. The patients with ISH show a trend, though not statistically significant, toward a lower level of Vitamin D compared to the nonhypertensive population.