Serum magnesium deficiency and its metabolic-vascular correlates in adults with type 2 diabetes mellitus at a Nigerian Tertiary Hospital

OBJECTIVES: To compare serum magnesium levels between patients with type 2 diabetes mellitus (T2DM) and age- and sex-matched non-diabetic controls, and evaluate the relationship between serum magnesium, β-cell function, glycaemic control, nephropathy, and peripheral arterial disease (PAD). RESULTS: In this hospital-based cross-sectional study, 83 patients with T2DM and 83 matched controls were evaluated. Serum magnesium was measured using inductively coupled plasma-optical emission spectrometry, while β-cell function and insulin resistance were assessed using the HOMA2 model. Nephropathy was assessed by albumin-creatinine ratio, and PAD by ankle-brachial index. Median serum magnesium levels were significantly lower in patients with T2DM than in controls [0.40 (0.30-0.43) vs. 0.88 (0.76-1.02) mmol/L, p < 0.001]. Hypomagnesaemia was present in all diabetic participants. Serum magnesium correlated positively with HOMA2-%β (rho = 0.47, p = 0.002), fasting insulin (rho = 0.42, p = 0.003), and HOMA2-IR (rho = 0.43, p = 0.004), but not HbA1c (rho = - 0.13, p = 0.21). Patients with microalbuminuria had significantly lower β-cell function indices (p = 0.002), while serum magnesium showed no significant association with albuminuria or PAD. These findings suggest that hypomagnesaemia is prevalent among Nigerian patients with T2DM and may reflect impaired β-cell function rather than established vascular complications.