Obesity and Overweight in Relation to Mortality in Men With and Without Type 2 Diabetes/Impaired Glucose Tolerance

In studies of apparently healthy individuals, overweight and obesity, typically assessed using BMI, have been consistently associated with an increased risk of all-cause mortality, cardiovascular disease (CVD), and select cancers (1– 4). However, extrapolating these results to individuals with type 2 diabetes is complex and perhaps inappropriate. Studies of the influence of obesity and overweight on mortality risk in individuals with type 2 diabetes reveal highly inconsistent findings. With all-cause mortality, obesity shows inverse (5,6), positive (7–10), null (11–16), and “J-” or “U-” shaped (17–19) associations; similarly discrepant results are apparent with coronary heart disease (CHD) (10,12,20,21). This discordance may be at least partially explained by methodological limitations in some studies, such as a modest sample size, a differential categorization of weight across studies, a tendency not to separate diabetes into its two main subtypes, and a failure to adjust for potentially important mediating and confounding variables. Using an extended follow-up of a U.K. prospective cohort study, we addressed this paucity of evidence and methodological shortcomings.