Poor diets account for most newly diagnosed type 2 diabetes cases worldwide, a new analysis has found.
More specifically, the modeling study showed that roughly 14 million cases of type 2 diabetes – or 70% of total type 2 diabetes diagnoses in 2018 – were linked with a poor diet, found Meghan O’Hearn, a doctoral student at the Friedman School of Nutrition Science and Policy, Tufts University, Boston, and colleagues. The study was published online in Nature Medicine.
The results also indicate that the greatest burdens of type 2 diabetes were accounted for by excess wheat intake and refined rice (24.6%), excess processed meat consumption (20.3%), and inadequate whole-grain consumption (26.1%). Factors such as drinking too much fruit juice and not eating enough nonstarchy vegetables, nuts, or seeds, had less of an impact on new cases of the disease, the researchers determined.
“These findings can help inform nutritional priorities for clinicians, policymakers, and private sector actors as they encourage healthier dietary choices that address this global epidemic,” Ms. O’Hearn said in a press release.
Prior research has suggested that poor diet contributes to about 40% of type 2 diabetes cases worldwide, the researchers note.
The team attributes their finding of a 70% contribution to the new information in their analysis, such as the first-ever inclusion of refined grains, which was one of the top contributors to diabetes burden, and updated data on dietary habits based on national individual-level dietary surveys rather than agricultural estimates.
“Our study suggests poor carbohydrate quality is a leading driver of diet-attributable type 2 diabetes globally and with important variation by nation and over time,” said senior author Dariush Mozaffarian, MD, DrPh, MPH, who is the Jean Mayer Professor of Nutrition at the Friedman School of Nutrition Science and Policy.
“These new findings reveal critical areas for national and global focus to improve nutrition and reduce devastating burdens of diabetes,” he noted.
“Left unchecked and with incidence only projected to rise, type 2 diabetes will continue to impact population health, economic productivity, [and] health care system capacity, [as well as] drive health inequities worldwide,” Ms. O’Hearn said.
It’s about reducing harmful dietary components
Ms. O’Hearn and colleagues set out to fill information gaps in knowledge about how the global burden of diet-associated type 2 diabetes is impacted by disparities and other factors known to influence risk, including dietary components.
They used information from the Global Dietary Database to study dietary intake in 184 nations from 1990 to 2018. They also studied demographics from multiple sources, estimates of type 2 diabetes incidence around the world, and data on food choices, including the effect of 11 dietary factors, from prior research.
They found that there were 8.6 million more cases of type 2 diabetes in 2018 than in 1990 because of poor diet.
Regionally, Central and Eastern Europe and Central Asia had the greatest number of type 2 diabetes cases linked to diet, particularly Poland and Russia, where diets tend to be rich in red meat, processed meat, and potatoes. Incidence was also high in Latin America and the Caribbean, especially in Colombia and Mexico, which was attributed to high consumption of sugary drinks and processed meat and low intake of whole grains.
Regions where diet had less of an impact on type 2 diabetes cases included South Asia and sub-Saharan Africa, although the largest increases in type 2 diabetes due to poor diet between 1990 and 2018 were observed in sub-Saharan Africa.
Diet-attributable type 2 diabetes was generally larger among urban versus rural residents and higher versus lower educated individuals, except in high-income countries, Central and Eastern Europe, and Central Asia, where burdens were larger in rural residents and in lower educated individuals.
Notably, women had lower proportions of diet-related type 2 diabetes, compared with men, and these proportions were inversely related to age.
Excess intake of harmful dietary factors contributed a greater percentage of the burden of type 2 diabetes globally (60.8%) than did insufficient intake of protective dietary factors (39.2%).
“Future research should address whether more complex diet–type 2 diabetes dose–response relationships exist,” the authors conclude.
Ms. O’Hearn has reported receiving research funding from the Gates Foundation, as well as the National Institutes of Health and Vail Innovative Global Research and employment with Food Systems for the Future. Dr. Mozaffarian has reported receiving funding from the National Institutes of Health, the Gates Foundation, the Rockefeller Foundation, Vail Innovative Global Research, and the Kaiser Permanente Fund at East Bay Community Foundation; personal fees from Acasti Pharma, Barilla, Danone, and Motif FoodWorks; is on the scientific advisory board for Beren Therapeutics, Brightseed, Calibrate, DiscernDx, Elysium Health, Filtricine, HumanCo, January, Perfect Day, Tiny Organics and (ended) Day Two and Season Health; has stock ownership in Calibrate and HumanCo; and receives chapter royalties from UpToDate.
A version of this article first appeared on Medscape.com.