Unhealthy eating blamed for rise in T2D cases worldwide

Poor dietary choices have driven type 2 diabetes (T2D) up to a staggering 14.1 million cases in 2018, accounting for about 70 percent of all new T2D diagnoses around the world, according to a study.

In a risk assessment model based on dietary intake data from the Global Dietary Database (GDD) that covers 184 countries, 11 dietary factors appeared to have direct and body weight-mediated effects on the global incidence of T2D. Three of these dietary factors contributed to the largest number of estimated T2D cases: insufficient whole-grain intake (26.1 percent), excessive refined rice and wheat intake (24.6 percent), and too much processed meat intake (20.3 percent). [Nat Med 2023;29:982-995]

Across regions, highest diet-attributable T2D burdens were seen in central and eastern Europe and central Asia (85.6 percent), particularly in populous countries such as Poland and Russia, where diets often contain an abundance of red meat, processed meat, and potatoes. This was followed by Latin America and the Caribbean (81.8 percent), specifically in Colombia and Mexico, where sugary drinks and processed meat are typically found in many people’s diets.

The lowest number of estimated T2D cases was seen in South Asia (55.4 percent) and sub-Saharan Africa (68.1 percent). Of the 30 most populated countries studied, India, Nigeria, and Ethiopia had the fewest cases of T2D related to unhealthy eating.

“The proportional diet-attributable T2D burden was inversely correlated with age and was generally greater in men versus women, urban versus rural residents, and for individuals with higher versus lower education, except in high-income countries and central and eastern Europe and central Asia, where the reverse was true for urbanicity and education level,” the investigators pointed out.

Meanwhile, national diet-attributable T2D burdens had only a modest correlation with socioeconomic development, with the association weakening since 1990.

“Poor carbohydrate quality is a leading driver of diet-attributable T2D globally, and with important variation by nation and over time,” stated senior author Dariush Mozaffarian of the Friedman School of Nutrition Science and Policy, Tufts University in Boston, Massachusetts, US.

The current suboptimal diet-attributable worldwide T2D cases estimate of 70 percent was much higher than the reported estimates of between 35 percent and 41 percent in previous studies. Mozaffarian and colleagues pointed out that this discrepancy may be attributed to the new information in their analysis, which factored in the effect of refined grains, considered as one of the top contributors to diabetes burdens. [Sci Rep 2020;10:1479; Lancet 2019;393:1958-1972; Lancet Diabetes Endocrinol 2022;10:655-667]

Additionally, the current study included updated data on dietary habits based on national individual-level dietary surveys rather than on agricultural estimates, they continued.

“These new findings reveal critical areas for national and global focus to improve nutrition and reduce devastating burdens of diabetes,” Mozaffarian said.

First author Meghan O'Hearn, a doctoral student at the Friedman School of Nutrition Science and Policy, highlighted the consequences of the sustained rise of T2D: “Left unchecked and with incidence only projected to rise, T2D will continue to impact population health, economic productivity, healthcare system capacity, and drive health inequities worldwide.”

O'Hearn, Mozaffarian, and the rest of the team believe that the findings can inform nutritional priorities for stakeholders (eg, clinicians, policymakers, and private sector actors) as well as guide clinical and public health planning to improve dietary quality and reduce T2D globally.