A diet with a high glycemic index is associated with an increased risk of a major cardiovascular event or death, with a hazard ratio of 1.51 among participants with preexisting cardiovascular disease and 1.21 among those without such disease.

After performing extensive adjustments comparing the lowest and highest glycemic-index quintiles, we found that a diet with a high glycemic index was associated with an increased risk of a major cardiovascular event or death, both among participants with preexisting cardiovascular disease (hazard ratio, 1.51; 95% confidence interval [CI], 1.25 to 1.82) and among those without such disease (hazard ratio, 1.21; 95% CI, 1.11 to 1.34).