Glycemic Index and Cardiovascular Disease

Quick Takes

  • Across multiple countries and geographic and economic regions, diets with a high glycemic index were associated with a higher risk of cardiovascular disease and death than diets with a low glycemic index.
  • This study underscores that the glycemic index and glycemic load are relevant measures of carbohydrate quality in the analysis of a wide range of different dietary patterns according to their association with adverse health outcomes.

Study Questions:

What is the association between the glycemic index and cardiovascular disease and all-cause mortality in a large study involving participants with a broad range of carbohydrate intakes and diverse dietary patterns?

Methods:

The investigators analyzed 137,851 participants between the ages of 35 and 70 years living on five continents, with a median follow-up of 9.5 years. They used country-specific food-frequency questionnaires to determine dietary intake and estimated the glycemic index and glycemic load on the basis of the consumption of seven categories of carbohydrate foods. The primary outcome was a composite of a major cardiovascular event (cardiovascular death, nonfatal myocardial infarction, stroke, and heart failure) or death from any cause. The authors calculated hazard ratios using multivariable Cox frailty models.

Results:

In the study population, 8,780 deaths and 8,252 major cardiovascular events occurred during the follow-up period. After performing extensive adjustments comparing the lowest and highest glycemic-index quintiles, the authors 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 pre-existing cardiovascular disease (hazard ratio [HR], 1.51; 95% confidence interval [CI], 1.25-1.82) and among those without such disease (HR, 1.21; 95% CI, 1.11-1.34). Among the components of the primary outcome, a high glycemic index was also associated with an increased risk of death from cardiovascular causes. The results with respect to glycemic load were similar to the findings regarding the glycemic index among the participants with cardiovascular disease at baseline, but the association was not significant among those without pre-existing cardiovascular disease.

Conclusions:

The authors concluded that a diet with a high glycemic index was associated with an increased risk of cardiovascular disease and death.

Perspective:

This study reports that across multiple countries and geographic and economic regions, diets with a high glycemic index were associated with a higher risk of cardiovascular disease and death than diets with a low glycemic index. Of note, the cultural and socioeconomic diversity of this study permits an examination of the association between glycemic index and glycemic load with events across a very broad range of dietary patterns. This study also underscores that the glycemic index and glycemic load are relevant measures of carbohydrate quality in the analysis of a wide range of different dietary patterns according to their association with adverse health outcomes.

Keywords: Carbohydrates, Cardiovascular Diseases, Diet, Eating, Glycemic Index, Heart Failure, Metabolic Syndrome, Myocardial Infarction, Outcome Assessment, Health Care, Primary Prevention, Socioeconomic Factors, Stroke, Vascular Diseases


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