Results of a recent study published in The New England Journal of Medicine showed that diets with a high glycemic index were associated with a higher risk of cardiovascular disease and death.
Investigators highlighted the dearth in equitably in research focused on the association between glycemic index and cardiovascular disease. As a result, the study selected countries depicting large and geographically diverse populations.
The analysis incorporated more than 137,000 patients across 20 countries and 5 continents between the ages 35 and 70 years. The analysis purposely included a spectrum of income levels: 4 high-income countries, 11 middle-income countries, and 5 low-income countries.
Standardized questionnaires were used to amass participant data on demographic factors, socioeconomic status (education, income, and employment), lifestyle (smoking, physical activity, and alcohol intake), health history, and medication use. Data was additionally collected through standard case-report forms on major cardiovascular events and death during follow-up, which was a median of 9.5 years (range, 3.2 to 11.9).
To determine dietary intake, and, consequently, to estimate glycemic index and glycemic load, investigators employed country-specific food-frequency questionnaires. The questionnaire aided researchers in calculating each participant’s daily intake of foods and 45 nutrients, which was ascertained by multiplying the frequency of consumption of each unit of food by the nutrient content by using both the US Department of Agriculture food-consumption databased and culture-specific food-composition tables for local meals. Glycemic load was determined by multiplying the mean net carbohydrate intake in grams per day by the glycemic index, then dividing by 100.
The analysis revealed that China, followed by Africa and Southeast Asia, had the highest consumption of diets and specific foods with a high glycemic index. In addition, diets with a high glycemic load were highest in South Asia, followed by Africa and China.
Major cardiovascular events occurred in 14,075 participants, including 8780 deaths, 3229 of which were definitive or possible cardiovascular deaths.
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. Another 8252 participants had at least 1 major cardiovascular event: 3579 with myocardial infarction, 3840 with stroke, and 923 with heart failure.
“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,” the study authors wrote. “The addition of our data to a recent meta-analysis that was commissioned by the World Health Organization strengthened the association between glycemic index and death from cardiovascular disease.”
- Jenkins DJ, Dehghan M, Mente A, et al. Glycemic index, glycemic load, and cardiovascular disease and mortality. The New England Journal of Medicine; February 24, 2021. Accessed March 2, 2021. doi: 10.1056/NEJMoa2007123.