Joint Effects of Serum 25(OH) D and C-Reactive Protein Concentration on Coronary Heart Disease and All-cause Mortality in Patients with Diabetes Mellitus

The study aimed to examine the joint predicting effect of serum 25(OH) D (a biomarker of vitamin D level in blood) and C-reactive Protein (CRP) concentration on the risk of mortality from Coronary Heart Disease (CHD) and all-causes in patients with type 2 Diabetes Mellitus (T2DM) using data from the third National Health and Nutrition Examination Survey (NHANES III). Of 14965 subjects aged ≥ 30 years who participated in the NHANESIII, 2146 patients with T2DM at baseline (1988-1994) were followed up through December 31 of 2006. The associations of baseline serum 25(OH) D and CRP with outcomes were examined prospectively using Cox's hazard proportional regression models. The results show that during a median follow-up of 12.3 years, 1257 (58.6%) of the patients with T2DM died, and 370 deaths were from CHD. Multivariate adjusted Cox's models indicate that decreased 25(OH) D level significantly predicted risk of death. The corresponding hazard ratios for the risk of CHD mortality among those with serum 25(OH) D levels 20-29.9, 10-19.9, and <10 ng/mL were 1.35, 1.38 and 2.19, as compared to those with 25(OH) D ≥ 30 ng/mL, respectively. Similar associations between decreased 25(OH) D and risk of all-cause mortality were observed. Furthermore, a joint effect of decreased 25(OH) D and increased CRP significantly predicted an increased risk of CHD and all-cause mortality. In conclusion, using data from a nationally representative and longitudinal survey, findings from the study suggest that decreased serum vitamin D and increased CRP concentrations significantly predicted the risk of CHD and all-cause mortality in patients with T2DM.