Association between body mass index and all-cause mortality in older people: A prospective analysis of the Chilean National Health Survey 2009-2010

There is a divergence in the results of studies that have explored the association between body mass index (BMI) and health outcomes in different contexts. Aim: This study investigated the association between BMI and all-cause mortality in older Chilean people. Methods: 1.205 participants (>= 60 years) from the Chilean National Health Survey 2009-2010 were included. The association between BMI categories and all-cause mortality was carried out using Cox proportional regression models, adjusting by confounding factors. Results: Over a median follow-up of 10.9 years (interquartile range: 8.7-11.0), 404 individuals died (33.5%). In the minimally adjusted model (model 1), the participants underweight had 1.46-times (95 CI %: 1.10;1.94) higher mortality risk, while those with obesity exhibited a 1.73-times (95 CI %: 1.05; 2.83) higher risk of dying due to all-causes compared with the normal-weight. After adjusting for models 2 and 3, the observed association remained significant. Conclusion: Older people categorized as underweight and obese II had a higher risk of all-cause mortality than their normal-weight peers, regardless of confounding factors.