According to a new study published in JAMA, individuals who are normal weight when diagnosed with diabetes have higher rates of death than individuals who are overweight or obese at the time of diagnosis.

The researchers explain:

Type 2 diabetes in normal-weight adults is an understudied representation of the metabolically obese normal-weight phenotype that has become increasingly common over time. It is not known whether the ‘obesity paradox’ that has been observed in chronic diseases such as heart failure, chronic kidney disease, and hypertension extends to adults who are normal weight at the time of incident diabetes.”

In order to compare death rates between individuals who were normal weight at the time of new adult-onset diabetes with those who were overweight or obese at diagnosis, Mercedes R. Carnethon, Ph.D., of the Feinberg School of Medicine, Northwestern University, Chicago, and colleagues examined data from five studies that involved 2,625 participants with new diagnosed diabetes.

The study included individuals aged 40+ who developed incident diabetes based on fasting glucose 126 mg/dL or greater or newly initiated diabetes medication and who had concurrent measurements of body mass index (BMI).

Participants with a BMI of 18.5 to 24.99 were classified as normal weight while those with a BMI of 25+ were classified as overweight or obese.

According to the researchers 449 participants died during the follow-up period:

  • 178 participants died from cardiovascular causes
  • 253 died from non-cardiovascular causes
  • 18 participants causes of death were unidentified

The team found that total mortality and cardiovascular and non-cardiovascular mortality was higher among patients of normal weight than among those who were overweight or obese. Normal weight patients were considerably more likely to experienced elevated total mortality and non-cardiovascular mortality. The researchers note that although cardiovascular mortality was elevated, the link was not statistically significant.

They explained:

“These findings are relevant to segments of the U.S. population, including older adults and nonwhite persons (e.g., Asian, black), who are more likely to experience normal-weight diabetes.

However, previous research suggests that normal-weight persons with diabetes have a different genetic profile than overweight or obese persons with diabetes. If those same genetic variants that predispose to diabetes are associated with other illnesses, these individuals may be ‘genetically loaded’ toward experiencing higher mortality. Future research in normal-weight persons with diabetes should test these genetic hypotheses, along with other plausible mechanisms to account for higher mortality, including inflammation, the distribution and action of adipose tissue, atherosclerosis burden and the composition of fatty plaques, and pancreatic beta-cell function.”

In an associated report, Hermes Florez, M.D., M.P.H., Ph.D., and Sumaya Castillo-Florez, M.D., M.P.H., of the University of Miami Miller School of Medicine, and Miami Veterans Affairs Healthcare System, explain that: “The article by Carnethon et al addresses an emerging challenge regarding diabetes and weight status.

This could be a wake-up call for timely prevention and management to reduce adverse outcomes in all patients with type 2 diabetes, particularly in those metabolically obese normal-weight at diagnosis, who may have a false sense of protection because they are not overweight or obese.

Standards of diabetes care recommend weight loss for all overweight or obese individuals who have diabetes. Low carbohydrate, low-fat, calorie-restricted, or Mediterranean diets may be effective weight-loss strategies in these individuals. The additional benefits of increased physical activity and behavior modification strategies amy lead to the successful implementation of weight management and healthy living programs for all patients with diabetes.

It is important to understand how diabetes duration relates to the benefits of intentional weight loss, as well as the clinical consequence associated with sarcopenic obesity and bone loss in older adults with or at high risk for diabetes.”

Written by Grace Rattue