Meta-analysis of dietary glycemic load and glycemic index in relation to risk of coronary heart disease

A high glycemic diet may increase cardiovascular risk, yet whether the risk differs by gender or adiposity is inconclusive. Our goal was to determine the associations between dietary glycemic load (GL) and glycemic index (GI), and coronary heart disease (CHD) risk by conducting a meta-analysis of prospective studies. We searched the PubMed and Embase databases in July 2011 to identify eligible studies. The random-effects model was used to calculate pooled relative risks (RRs) comparing the highest categories of exposure to the lowest. Prespecified subgroup analyses were performed by gender and body mass index. We identified 8 prospective studies for meta-analysis, consisting of 220,050 participants and 4,826 incident CHD cases. Pooled RRs of CHD in relation to dietary GL were 1.08 (95% confidence interval [CI] 0.92 to 1.27) for men, 1.69 (95% CI 1.32 to 2.16) for women, and 1.36 (95% CI 1.13 to 1.63) for men and women combined. For dietary GI, corresponding pooled RRs were 0.99 (95% CI 0.84 to 1.16), 1.26 (95% CI 1.12 to 1.43), and 1.13 (95% CI 1.00 to 1.28), respectively. Limited evidence suggested the associations appeared more evident in the overweight and obese. There was no indication of publication bias. In conclusion, high dietary GL and GI significantly increased the risk of CHD in women but not in men, and the unfavorable effects may be more pronounced in overweight and obese patients. Further studies are needed to verify these findings and elucidate the underlying mechanisms.