Author Insights: An Obesity Paradox Found Among Some Patients With Type 2 Diabetes

Mercedes R. Carnethon, PhD, Feinberg School of Medicine, Northwestern University, Chicago, and colleagues found evidence suggesting that adults at normal weight at the time of a diabetes diagnosis may have a higher risk of death compared with those who are overweight or obese at the time of diagnosis. (Image: Hanson-Carnethon Photography)

Public health officials warn that today’s obesity epidemic could result in tomorrow’s type 2 diabetes epidemic. And while obesity is associated with the development of diabetes, a paradox has emerged suggesting that some patients who are of normal weight when they are diagnosed with the disease have a higher risk of death compared with their overweight or obese counterparts.

A pooled analysis of 5 cohort studies involving 2625 participants appearing today in JAMA found that the rate of death among adults who were normal weight (body mass index [BMI] of 18.5-24.99) at the time of their diabetes diagnosis was 284.8 per 10 000 person-years compared with a death rate of 152.1 per 10 000 person-years among individuals who were overweight or obese at the time of diagnosis. After adjusting for demographic characteristics, blood pressure, lipid levels, waist circumference, and smoking status, normal-weight individuals were more than twice as likely to die compared with overweight or obese persons.

Lead author Mercedes R. Carnethon, PhD, of the Feinberg School of Medicine, Northwestern University, Chicago, discusses her team’s findings:

“You would assume that if normal-weight people just had diabetes and not coronary heart disease, which is seen more often in those overweight and obese, that they would do better. And so we were somewhat surprised that they did much worse. But our findings are consistent with other studies of people with hypertension, end-stage renal disease, and congestive heart failure: those with these conditions have higher death rates if they are normal weight.

“Only about 5% to 15% of people with diabetes are also normal weight, but with the aging of the population—the average onset of diabetes is between 65 and 75 years—physicians will be seeing more normal-weight patients with diabetes. This is important to remember when seeing Asian patients, who tend to have a lower body weight than non-Asians.

“There is the risk that the wrong conclusions could be taken from our findings. They don’t mean that normal-weight people with diabetes should gain weight or overweight or obese people should avoid losing weight. We wanted to communicate to physicians in the clinical setting that relying solely on BMI is problematic because people who may not otherwise raise your clinical suspicions may have clinical problems.”

Categories: Diabetes Mellitus, Nutritional and Metabolic Disorders, Obesity