Hypomagnesaemia and risk for metabolic glucose disorders: a 10-year follow-up study.

BACKGROUND Although several lines of evidence suggest that hypomagnesaemia is a risk factor for developing type 2 diabetes, there are no studies regarding the association between hypomagnesaemia and the risk for developing impaired fasting glucose (IFG) or impaired glucose tolerance (IGT). Our objective was to examine the association between serum magnesium levels and the risk for developing IFG, IGT and type 2 diabetes. MATERIALS AND METHODS A total of 1122 individuals (20-65 years of age) were enrolled between 1996 and 1997, and 817 individuals re-examined about 10 years later. New-onset IFG (5.6-7.0 mmol L(-1) fasting glucose), IGT (7.8-11.1 mmol L(-1) glucose 2-h postload), and type 2 diabetes were determined from the number of subjects who had these conditions at the second examination without evidence that they were present at the first one. The relative risk of new-onset metabolic glucose disorders and diabetes (dependent variables) was computed using Poisson regression model adjusted for age, sex, family history of diabetes, waist circumference and homeostasis model assessment for insulin resistance index. Serum magnesium levels of < 0.74 mmol L(-1) (independent variable) defined the exposed group. RESULTS At baseline, 420 (51.4%) individuals had hypomagnesaemia. New-onset IFG and IGT was identified in 276 (33.8%) individuals. The relative risk for IFG, IGT and IFG + IGT was 1.11 (95% confidence interval, 0.5-5.1), 1.38 (95% confidence interval, 1.1-6.3) and 1.49 (95% confidence interval, 1.1-4.9), respectively. New-onset diabetes was identified in 78 (9.5%) individuals (relative risk 2.54; 95% confidence interval, 1.1-4.1). CONCLUSIONS Hypomagnesaemia is independently associated with the development of IGT, IFG + IGT and type 2 diabetes, but not with the development of IFG.