Impaired fasting glucose and the risk of incident diabetes mellitus and cardiovascular events in an adult population: MESA (Multi-Ethnic Study of Atherosclerosis)

Objectives: The purpose of the study was to assess the cardiovascular risk of impaired fasting glucose (IFG). Background: The associations between IFG, incident type 2 diabetes mellitus (T2DM), and cardiovascular (CV) events remains unclear. Methods: The MESA (Multi-Ethnic Study of Atherosclerosis) study included participants who were 45 to 84 years or age and free of clinical CV disease at baseline (2000 to 2002). Type 2 DM was defined as fasting glucose >125 mg/dl or receiving antidiabetes medication at baseline and follow-up examinations; IFG was defined as no T2DM and fasting glucose 100 to 125 mg/dl. Cox proportional hazards analysis was used to assess the association between IFG and incident DM and also between IFG and incident CV events. Results: Of 6,753 participants included in these analyses, 840 (12.7%) had T2DM and 940 (13.8%) had IFG at the baseline examination. During 7.5 years of follow-up, there were 418 adjudicated CV events. Type 2 DM was associated with an increased CV incidence in the univariate model (hazard ratio [HR]: 2.83, 95% confidence interval [CI]: 2.25 to 3.56, p < 0.0001) and multivariate model adjusted for demographics and traditional risk factors (HR: 1.87, 95% CI: 1.47 to 2.37, p < 0.0001) compared with subjects not having T2DM (IFG plus normal fasting glucose). Impaired fasting glucose was associated with increased incidence of T2DM (HR: 13.2, 95% CI: 10.8 to 16.2, p < 0.001) that remained after adjusting for demographics, highest educational level, physical activity, and body mass index (HR: 10.5, 95% CI: 8.4 to 13.1, p < 0.001) compared with normal fasting glucose. Impaired fasting glucose was associated with incident CV events in the univariate model (HR: 1.64, 95% CI: 1.26 to 2.14, p < 0.001) but not in the full multivariate model (HR: 1.16, 95% CI: 0.88 to 1.52, p = 0.3) compared with normal fasting glucose. Conclusions: Having IFG was not independently associated with an increased short-term risk for incident CV events. These data reiterate the importance of intervention for persons with IFG to reduce their incidence of T2DM.