Serum Lipids and Lipoproteins Levels and Selected Trace Metals In Newly Diagnosed Hypertensive Nigerians
There have been several reports on the role of macronutrients in the pathogenesis of high blood pressure (HBP), however, reports on the relationship between micronutrients and trace metals are few, especially in blacks. This study aim to determine the serum levels of trace metals and correlate same with serum levels of lipoproteins (an established marker of HBP) in newly diagnosed hypertensives (NDH) A total of 50 NDH subjects (24 males and 26 females) attending Ladoke Akintola University of Technology Teaching Hospital, Osogbo were randomly selected and recruited after obtaining their informed consent. 62 consenting healthy individuals (28 males and 34 females) were recruited from member of staff as controls. Fasting blood samples were collected from subjects and controls using appropriate techniques. Serum Total cholesterol (Tc), triglycerides (TG), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) were estimated using commercially available kit from Randox Laboratory. Trace metals (Selenium(Se), Zinc(Zn), Cobalt(Co) and Copper(Cu)) were analyzed using flame atomic absorption spectrophotometry. Data obtained were analyzed with the aid of SPSS statistical package version 18.0. Serum Tc and LDL-Chol were higher in subjects (5.69 ±1.40 and 3.85±0.94) mmol/l than in controls (4.53±1.30 and 2.56±1.38) mmol/l, p <0.05 respectively. Mean serum HDL-Chol was reduced in NDH compared with controls 1.10±0.43 vs 1.35±0.22 mmol/l, p > 0.05. Serum Tg were almost similar Preamong subjects and controls 1.40±0.21 vs 1.34±0.67mmol/l, p > 0.05. Reduced levels of Se and Zn were found in NDH (8.55±5.61, 70.44±28.48μg/dl) compared with controls (21.75±7.30, 120.15±25.76μg/dl), p < 0.05 respectively. On the contrary, elevated Co and Cu were found in NDH (4.78±2.30, 129.00±30.90μg/dl) compare with controls ( 3 . 1 0 ± 1 . 2 5 , 93.80±22.30μg/dl) p < 0.05 respectively. Strong positive correlations exist between Se and Zn, r = 0.805, p <0.05 and between Co and Cu, r = 0.685, p < 0.05 in NDH. Strong negative correlation were also seen between Se and Cu, r= -0.702 and between Cu and Zn, r = -0.730, p < 0.05 respectively in NDH. We conclude that hyperlipidaemia has once again been associated with high blood pressure. Reduced Zn and Se observed in NDH may be a predisposing factor to oxidative stress in the etiopathogenesis of high blood pressure. Increased cobalt observed in this study has been previously linked with the development of oxidative stress. We conclude that trace metals disturbances may contribute to the pathogenesis of hypertension.
Key words: lipids, lipoproteins, micronutrients, newly diagnosed black hypertensives.