The association between plasma zinc concentrations and markers of glucose metabolism in adults in Cameroon

An abnormal zinc status has been suggested to play a role in the pathogenesis of type 2 diabetes. However, epidemiological studies of the relationship between plasma zinc concentrations and diabetes are sparse and inconclusive. We aimed to investigate the association between plasma zinc concentrations and glycaemic markers (fasting glucose, 2-h glucose and HOMA-IR) in rural and urban Cameroon. We studied 596 healthy adults (63.3% women) aged 25-55 years in a population-based cross-sectional study. The mean plasma zinc concentration was 13.7±2.7 μmol/L overall, with higher levels in men (14.4±2.9 μmol/L) than in women (13.2±2.6 μmol/L), p-value < 0.0001. There was an inverse relationship between tertiles of plasma zinc and 2-h glucose concentrations (p-value for linear trend=0.002). The difference in 2-h glucose between those in the highest tertile of plasma zinc compared to the lowest was -0.63(95% CI -1.02 to -0.23) mmol/L. This remained significant after adjusting for age, sex, smoking status, alcohol intake, education level, area of residence, adiposity and objectively measured physical activity -0.43(-0.82 to -0.04). Similar inverse associations were observed between plasma zinc concentrations and fasting glucose and HOMA-IR when adjusted for socio-demographic and health-related behavioural characteristics. The current findings of an inverse association between plasma zinc concentrations and several markers of glucose homeostasis, together with growing evidence from intervention studies suggest a role for zinc in glucose metabolism. If supported by further evidence, strategies to improve zinc status in populations may provide a cheap public health prevention approach for diabetes.