Baseline cardiac troponin t levels are elevated in subjects with untreated diabetes mellitus: A cross-sectional study

Objective: Cardiac troponins are biomarkers of myocardial injury and serve both diagnostic and prognostic purposes. Even mild elevations represent subclinical myocardial damage in the general population. The objective of this study was to investigate the relationship between glucometabolic status and cardiac troponin T in middle-aged or older apparently healthy subjects. Design and method: We examined cross-sectional associations between highsensitivity cardiac troponin T (hsTnT) and FPG categorized as normal fasting glucose (NFG: FPG/=7.0mmol/L), in 535 men and 226 women aged 56-79 years without overt cardiovascular disease who received no cardiovascular, antidiabetic or lipid lowering drugs, using multiple linear regression analysis. Results: FPG category (r = 0.159; p <0.001) was positively correlated with hsTnT. Mean hsTnT levels increased significantly with worsening glucometabolic status (NFG: 7.55 ng/L +/- standard deviation 3.99 ng/L; IFG: 8.09 ng/L +/- 6.81 ng/L; DM: 10.28 ng/L +/- 7.55 ng/L; p <0.001). Levels were significantly higher in subjects with DM compared to NFG (p <0.001) and IFG (p = 0.005), but there was no significant difference between subjects with NFG and IFG (p = 0.26). After adjusting for age and sex, FPG category remained significantly predictive of hsTnT (B = 1.08 [95% confidence interval (CI), 0.56-1.59]; p <0.001). After further adjusting for traditional cardiovascular risk factors, cystatin C levels, and electrocardiographic left ventricular hypertrophy (LVH) defined by the Sokolow-Lyon index and/or Cornell voltage-duration product,FPGcategory remained significantly associated with hsTnT (B = 0.87 [95% CI, 0.35-1.39]; p = 0.001), independently of age (B = 0.29 [95% CI, 0.22-0.36]; p <0.001), sex (B = 2.08 [95% CI, 1.20-2.95]; p <0.001), systolic blood pressure (B = 0.032 [95% CI, 0.012-0.051]; p = 0.001), and cystatin C (B = 3.69 [95% CI, 1.60-5.79]; p = 0.001). There was a significant interaction between FPG category and age (NFG: B= 0.22 [95% CI, 0.16-0.29]; IFG: B= 0.33 [95% CI, 0.18-0.48]; DM: B= 0.41 [95% CI, 0.20-0.62]; p = 0.03). Conclusions: In middle-aged or older apparently healthy subjects, untreated DM was associated with higher levels of hsTnT, independently of traditional cardiovascular risk factors. The importance of age increased with worsening glucometabolic status.