High intake of refined grains may be associated with an increased risk for major cardiovascular disease events and mortality, according to a study published in The British Medical Journal.

Data for this analysis  were obtained from the Prospective Urban Rural Epidemiology (PURE) database, which was a large prospective cohort study conducted across 21 countries (incomes: low, n=5; lower middle, n=5; upper middle, n=7; and high, n=7) between 2003 and 2019. Individuals (n=137,130) self-reported dietary consumption and were assessed for cardiovascular disease events and mortality.

Consumption of refined grains was highest among participants from China (median, 225 g/day; interquartile range [IQR], 72-455 g/day) and lowest among those living in South Asia (median, 30 g/day; IQR, 8-84 g/day). White rice consumption was highest in South Asia (median, 612 g/day; IQR, 110-948 g/day) and lowest among those living in North America and Europe (median, 23 g/day; IQR, 8-38 g/day).


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The study’s median follow-up was 9.5 years (IQR, 8.6-10.9 years), during which time 10.3% of participants had a composite outcome event (major cardiovascular disease events or mortality). Of 9279 deaths, 38.6% were associated with cardiovascular disease.

Individuals who consumed the highest vs lowest amount of refined grains were found to be at increased risk for stroke (hazard ratio [HR], 1.47; 95% CI, 1.22-1.77), major cardiovascular disease events (HR, 1.33; 95% CI, 1.15-1.52; P <.001), non-cardiovascular mortality (HR, 1.31; 95% CI, 1.10-1.56; P =.004), the composite outcome (HR, 1.28; 95% CI, 1.15-1.42; P <.001), and total mortality (HR, 1.27; 95% CI, 1.11-1.46; P =.004) after adjusting for covariates including diabetes.

For every 50-gram increase of refined grain consumption, HR for the composite event increased was 1.02 (95% CI, 1.01-1.03), and for every 200 kcal increase in carbohydrates, HR was 1.03 (95% CI, 1.00-1.05; P <.001).

Consumption of white rice and whole grains were not associated with increased risk for the composite event.

This study may have been limited by calculating approximate dry weights of grains for each region and not for each food item which possibly introduced bias as most regions consume grains in hydrated forms such as breads, porridges, or pancake-like foods.

“Intakes of a combination of cereal grains with a lower intake of refined wheat products should be encouraged while promoting a higher intake of whole grains,” concluded the study authors. “Reduction in quantity and improvement in quality of carbohydrate is essential for better health outcomes.”

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.

Reference

Swaminathan S, Dehghan M, Raj J M, et al. Associations of cereal grains intake with cardiovascular disease and mortality across 21 countries in Prospective Urban and Rural Epidemiology study: prospective cohort study. BMJ. 2021;372:m4948. doi:10.1136/bmj.m4948