Adults who were normal weight at the time they were diagnosed with type 2 diabetes had a higher risk of death than did their overweight or obese counterparts, research has revealed. As explained in the JAMA report (2012;308:581-590), 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.

“Many times [clinicians] don’t expect that normal-weight people have diabetes when it is quite possible that they do and could be at high risk of moratlity, particularly if they are older adults or members of a minority group,” explained first author Mercedes R. Carnethon, PhD, in a statement.

Investigators analyzed data from five cohort studies involving 2,625 participants with incident diabetes. The proportion of those who were normal weight (BMI 18.5 to 24.99) at the time of incident diabetes ranged from 9% to 21% in the studies, but was 12% overall.

During follow-up, 449 participants died: 178 from cardiovascular causes and 253 from noncardiovascular causes (18 deaths were not classified). The rates of total, cardiovascular, and noncardiovascular mortality were higher among normal-weight participants than among overweight/obese participants. After adjustments were made for demographic characteristics as well as for BP, lipid levels, waist circumference, and smoking status, hazard ratios comparing normal-weight with overweight/obese participants for total, cardiovascular, and noncardiovascular mortality were 2.08, 1.52, and 2.32, respectively.

Older adults and nonwhite participants were more likely to develop normal-weight diabetes. Previous research suggests that normal-weight persons with diabetes have a different genetic profile than do overweight/obese persons diagnosed with the disease.