The relationship between glucose and incident cardiovascular events

OBJECTIVE - To assess the relationship between nondiabetic glucose levels a nd cardiovascular risk. RESEARCH DESIGN AND METHODS - Three independent searches using MEDLINE (196 6-1996), followed by a manual search of the references from each retrieved article, were conducted by two physicians and one medical librarian. Data h ad to be reported in at least three quantiles or intervals so that the natu re of the relationship between glucose and cardiovascular events (i.e., lin ear or nonlinear) could be explored, and to ensure that any incremental car diovascular risk was consistent across quantiles or intervals. RESULTS - Analyzed studies comprised 95,783 people (94% male) who had 3,707 cardiovascular events over 12.4 years (1,193,231 person-years). Studies re porting fasting glucose levels (n = 6), 2-h glucose levels (n = 7), 1-h glu cose levels (n = 5), and casual glucose levels (n = 4) were included. The g lucose load used varied from 50 to 100 g. The highest glucose interval for most studies included glucose values in the diabetic range. The relationshi p between glucose levels and the risk of a cardiovascular event was modeled for each study and the p-coefficients were combined. Compared with a gluco se level of 4.2 mmol/l (75 mg/dl), a fasting and 2-h glucose level of 6.1 m mol/l (110 mg/dl) and 7.8 mmol/l (140 mg/dl) was associated with a relative cardiovascular event risk of 1.33 (95% CI 1.06-1.67) and 1.58 (95% CI 1.19 -2.10), respectively. CONCLUSIONS - The progressive relationship between glucose levels and cardi ovascular risk extends below the diabetic threshold.