Vitamin D Status and All-Cause Mortality in Patients With Type 2 Diabetes in China

OBJECTIVE: To assess the association between vitamin D status and all-cause mortality among type 2 diabetes patients. RESEARCH DESIGN AND METHODS: We prospectively followed 1,291 participants with type 2 diabetes aged 20–80 years during 2013–2018. Cox proportional hazard regression models were used to estimate the association between different vitamin D status and all-cause mortality risk among hospitalized patients with type 2 diabetes. RESULTS: During a median follow-up of 4.15 years (5,365 person-years in total), 61 cases of death were identified. Multivariable-adjusted hazard ratios (HRs) for all-cause mortality across the quartiles of baseline circulating 25-hydroxy vitamin D (25-OH vitamin D) were 2.70 [95% confidence interval (CI) 1.12–6.54], 1.00, 1.39 (95% CI 0.53–3.65), 2.31 (95% CI 0.96–5.54), respectively. Multivariable-adjusted HRs for all-cause mortality by different groups of baseline 25-OH vitamin D concentrations (<25, 25–49, 50–100, and ≥100 nmol/L) were 1.31 (95% CI 0.58–2.96), 0.94 (95% CI 0.47–1.87), 1.00, and 3.58 (95% CI 1.43–8.98), respectively. CONCLUSIONS: Very low or high concentrations of vitamin D may be associated with a higher risk of all-cause mortality among patients with type 2 diabetes.