Dietary Glycemic Load Linked to Coronary Heart Disease Risk in Women But Not Men

Laurie Barclay, MD

April 14, 2010

April 14, 2010 — High dietary glycemic load and carbohydrate intake from high-glycemic index foods are associated with an increased overall risk for coronary heart disease (CHD) in women but not in men, according to the results of a large, Italian cohort study reported in the April 12 issue of Archives of Internal Medicine.

"Dietary glycemic load (GL) and glycemic index (GI) in relation to cardiovascular disease have been investigated in a few prospective studies with inconsistent results, particularly in men," write Sabina Sieri, PhD, and colleagues from the EPICOR study. "The present EPICOR study investigated the association of GI and GL with ...CHD in a large and heterogeneous cohort of Italian men and women originally recruited to the European Prospective Investigation into Cancer and Nutrition study."

The study cohort consisted of 47,749 volunteers (15,171 men and 32,578 women) who completed a dietary questionnaire and were followed up for a median of 7.9 years. The investigators estimated adjusted relative risks (RRs) for CHD and 95% confidence intervals (CIs) using multivariate Cox proportional hazards modeling.

Of 463 patients with CHD identified during follow-up, 158 were women and 305 were men. Compared with women in the lowest quartile of carbohydrate intake, those in the highest carbohydrate intake quartile had a significantly greater risk for CHD (RR, 2.00; 95% CI, 1.16 - 3.43). This association was not observed in men (P for interaction = .04).

In women, increasing intake of carbohydrates from high-glycemic index foods, but not of low-glycemic index carbohydrates, was also significantly associated with greater CHD risk (RR, 1.68; 95% CI, 1.02 - 2.75). For women, but not for men, CHD risk was significantly greater for those in the highest glycemic load quartile vs those in the lowest quartile (RR, 2.24; 95% CI, 1.26 - 3.98; P for interaction =.03).

"In this Italian cohort, high dietary GL and carbohydrate intake from high-GI foods increase the overall risk of CHD in women but not men," the study authors write.

Limitations of this study include use of questionnaires that were not designed to estimate dietary glycemic index and glycemic load, and dietary exposure based on a single assessment in which participants were asked about eating habits during the preceding year.

"We tentatively suggest that the adverse effects of a high glycemic diet in women are mediated by sex-related differences in lipoprotein and glucose metabolism, but further prospective studies are required to verify a lack of association of a high dietary glycemic load with CVD [cardiovascular disease] in men," the study authors conclude.

The EPICOR study is supported by the Compagnia di San Paolo. The Italian EPIC collaboration is supported by the Associazione Italiana per la Ricerca sul Cancro. The study authors have disclosed no relevant financial relationships.

Arch Intern Med. 2010;170:640-647.


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