Obesity a Driver of Up to Half of Type 2 Diabetes Cases

For certain Americans, obesity contributed to roughly half of their new type 2 diabetes cases, according to a new study.

Using National Health and Nutrition Examination Survey (NHANES) data, obesity contributed to 41% of all new type 2 diabetes cases in the entire U.S. population, reported Sadiya Khan, MD, MSc, of Northwestern University Feinberg School of Medicine in Chicago, and colleagues in the Journal of the American Heart Association.

However, this impact varied across certain ethnic and racial groups following adjustment for multiple variables such as age, physical activity, diet, annual family income, and education level.

Specifically, non-Hispanic white women seemed to be hit the hardest by this relationship, with 53% of all incident diabetes cases driven by obesity in this group (adjusted population-attributable fraction [aPAF] 0.53, 95% CI 0.43-0.63).

This was followed by Mexican-American women (aPAF 0.42, 95% CI 0.21-0.63) and Black women (aPAF 0.39, 95% CI 0.24-0.55).

On the other hand, 30% of new diabetes cases among non-Hispanic Black men were attributed to obesity — the lowest of all groups (aPAF 0.30, 95% CI 0.19-0.40).

Mexican-American men saw the biggest jump in obesity-related incident diabetes rates. During the pooled survey cycle years of 2001 to 2004, only 22% of new diabetes cases each year were attributed to obesity. Fast forward to survey years 2013 to 2016, and obesity drove 38% of new diabetes cases for Mexican-American men.

On average, women of any race or ethnicity tended to have a larger proportion of new diabetes cases attributed to obesity versus men. Black and Mexican-American women also saw the highest rates of obesity throughout 2001 to 2016.

But for all Americans, the presence of obesity increased their risk of developing type 2 diabetes by nearly three-fold (adjusted hazard ratio 2.7, 95% CI 2.2-3.3).

“It was surprising to see the extent of the burden of diabetes that was attributed to obesity,” Khan explained to MedPage Today. “Nearly one-third to one-half of new cases of diabetes were attributed to obesity.”

She added that it was also rather surprising to see that Black women, who experience a greater prevalence of diabetes, had a lower proportion of new cases attributed to obesity compared with white women. “This points to other causes of diabetes that also need to be explored and complement focus on weight management to prevent diabetes in diverse populations, especially around social determinants of health.”

“We cannot emphasize the importance of optimization and maintenance of a healthy weight across the life course,” Khan continued. “But, it is important to develop multi-level strategies to support individuals in achieving this goal, including access to safe and green spaces for exercise, access to healthy foods, and to begin early in life. National policies, such as sugar sweetened beverage taxation, are also important.”

The researchers obtained data from the Multi-Ethnic Study of Atherosclerosis (MESA), a longitudinal cohort study, combined with data from NHANES cycles. Among the 4,200 MESA participants included, all were free of diabetes at baseline.

A larger proportion of those with obesity had an annual income of $50,000 or less, and were also more likely to be Black or Mexican American. During a median follow-up of 9.2 years, about 11.6% of the total population developed type 2 diabetes, while 20% of those with obesity developed diabetes.

In a statement, Khan added that the collision of the obesity epidemic with the COVID-19 pandemic could yield grave outcomes.

“The greater severity of COVID-19 infection in individuals with obesity is concerning because of the growing burden of adverse health consequences they could experience in the coming years,” she pointed out. “Therefore, further efforts are needed to help more adults adopt healthier lifestyles and hopefully reduce the prevalence of obesity.”

Last Updated February 10, 2021