Assessment of Parathyroid Hormone, Vitamin D, Calcium, and Renin-angiotensin-aldosterone System in Nigerians With Hypertension

Abstract

Background and Purpose: Hypertension is a major medical condition that can cause many complications and sudden death when not appropriately controlled. This study determined serum calcium, parathyroid hormone, vitamin D, renin, angiotensin II, angiotensin I converting enzyme, and aldosterone in hypertensive individuals, as these compounds play key roles in regulating human blood pressure. Materials and Methods: This case-control study was conducted on 549 (324 hypertensive cases and 225 controls) individuals between October 2018 and September 2020. Fasting blood samples were collected into plain vacutainer bottles to determine serum calcium, parathyroid hormone, vitamin D, and renin-angiotensin components using ion selective electrode and ELISA methods. Continuous and categorical variables were subjected to appropriate statistical analyses using the STATA version 16 (StataCorp LLC). Results: The demographic comparison showed that the mean age did not differ between the case and control groups, but the body mass index was higher (P<0.05) among the case group. The mean calcium value was elevated in the case group (2.41±0.26 mmol/L) vs the control group (2.20±0.54 mmol/L) (P<0.001). Comparing between case and control groups, the median values of parathyroid hormone (PTH) (47.26 pg/mL, interquartile range [IQR]=25.05-71.70 vs 26.43 pg/mL, IQR=17.67-45.70) (P<0.001), renin (339.77 pg/mL, IQR=227.61-566.89 vs pg/mL 269.295, IQR=159.30-420.13) (P<0.001), angiotensin II (402.74 pg/mL, IQR=253.79-594.77 vs 328.19 pg/mL, IQR=264.24-383.51) (P<0.001), angiotensin I converting enzyme (3.13 ng/mL, IQR=1.77-7.35 vs 1.82 ng/mL, IQR=1.25-3.58) (P<0.001), and aldosterone (307.18 pg/mL, IQR=204.05-502.32 vs 187.85 pg/mL, IQR=163.89-306.13) (P<0.001) were higher in the hypertensive group. However, Vitamin D (42.91 nmol/L, IQR=24.32-55.48 vs 55.33 nmol/L, IQR=42.67-99.73) was reduced (P<0.001) among hypertensive individuals. Multivariate analysis showed that increase in calcium (odds ratio=5.012, P<0.001; 95% CI, 2.885%, 8.707%, PTH (odds ratio=1.0204; P<0.001; 95% CI, 1.0139%, 1.02699%) and aldosterone (odds ratio=1.0008; P=0.001; 95% CI, 1.00032%, 1.00129%) were related with higher odds of hypertension and its associated complications.