New NHLBI clinical guidelines for obesity and overweight: Will they promote health?

Objectives. The purpose of this study ws to assess the justification, on th e basis of mortality, of the new National Heart, Lung, blood Institute (NHL BI) guidelines on obesity and overweight and to discuss the health implicat ions of declaring all adults with a body mass index of 25 through 29 "overw eight." Methods. The relationships between NHLBI body mass index categories and mor tality for individuals older than 31 years were analyzed for 6253 Alameda C ounty Study respondents aged 21 through 75 years. Time-dependent proportion al hazards models were used to adjust for changes in risk factors and weigh t during follow-up. Results. Adjusted relative risks of mortality for 4 NHLBI categories compar ed with the category "normal" indicated that only being underweight or mode rately/extremely obese were associated with higher mortality. Specific risk s varied significantly by sex. Conclusions. Our results are consistent with other studies and fail to just ify lowering the overweight threshold on the basis of mortality. Current in terpretations of the revised guidelines stigmatize too many people as overw eight; fail to account for sex, race/ethnicity, age, and other differences; and ignore the serious health risks associated with low weight and efforts to maintain an unrealistically lean body mass.