Blood Pressure and It’s Association with Heavy Metal Exposure andAdiposity Indices Among Overweight and Obese Adults in Kaélé,Cameroon: A Cross-Sectional Study

Abstract

Introduction: Hypertension is a major public health challenge worldwide. In low- and middle-income countries, hypertension is rapidly increasing and contributes substantially to premature mortality. It is commonly associated with overweight and obesity. Growing evidence also indicates that environmental pollutants, particularly heavy metals, play a significant role in the development of cardiometabolic disorders, including hypertension.

Objective: To assess the relationship between adiposity indices and dietary intake of heavy metals (lead (Pb), Cadmium (Cd), and Manganese (Mn)) from commonly consumed foods (baobab leaves, cowpea, and corète), and the associated risk of elevated blood pressure (BP) in the Kaélé village in the Far North Region of Cameroon.

Methods: This three-month cross-sectional descriptive study was conducted among overweight and obese adults (≥18 years) residing in Kaélé, Far North Cameroon. Anthropometric measurements (height, weight, waist and hip circumferences) and BP were recorded. Cooked food samples were subsequently analyzed for heavy metal (Pb, Cd and Mn), using atomic absorption spectrophotometry.

Results: Based on body mass index (BMI), 57.32% were overweight and 42.68% obese. According to the Body Adiposity Index (BAI), 68.29% were overweight and 31.71% obese. The prevalence of hypertension was 46.34% of the study population. BMI was the only adiposity index that was able to predict the increase in blood pressure (BP) [for a one-unit increase in BMI, an increase of 1.61 mmHg in systolic blood pressure (SBP) and 1.45 mmHg in diastolic blood pressure (DBP) was observed; with a beta coefficient of B = 1.609; p = 0.002; 95% CI: 0.618 – 2.600 for SBP and B = 1.445; p ˂ 0.001; 95% CI: 0.739 – 2.152 for DBP]. Total Cadmium (Cd) was the only predictor of hypertension in a polynomial regression model, where nonlinear relationships (quadratic and cubic) were observed. In the first regression, the quadratic and cubic models were found to be predictors of SBP with respective beta coefficients (B = 7.04 × 10-6; p = 0.003; 95% CI: 0.016 – 0.840) and (B = 5.64 × 10-9; p = 0.040; 95% CI: 0.000 – 0.000). Only the quadratic model was statistically significant with DBP (B = 5.42 × 10-6; p = 0.010; 95% CI: 0.000 – 0.000). A multiplicative interaction term between Cd and BMI (BMI × Cd_total) was used to evaluate the effect on BP, but the result was not statistically significant (p > 0.05).

Conclusion: The BMI was the only adiposity index found to be associated with the prevalence of hypertension. Regarding the different dietary heavy metal intakes, total Cd was the only predictor of BP in our study population.