No Survival Advantage for Obesity

A population-based study in the US did not find evidence of a survival advantage for obesity among persons with incident cardiovascular disease (CVD). The study used data from an ongoing, nationally representative longitudinal survey of more than 30,000 people age 50 years and older initiated in 1992, with follow-up through December 31, 2012. Cox proportional hazard models were used to estimate the association between weight status and mortality among persons with specific CVD diagnoses. Prevalent disease models used concurrent weight status, and incident disease models used pre-diagnosis weight status. A strong and significant obesity paradox was consistently observed in prevalent disease models (hazard of death 18–36% lower for obese class I relative to normal weight), replicating prior findings. However, in incident disease models of the same conditions in the same dataset, there was no evidence of this survival benefit. Findings from models using survey- vs. claims-based diagnoses were largely consistent. The findings suggest that the obesity paradox may be plagued by confounding in disease-related weight loss and selective survival. Source: http://journals.plos.org/