Leisure-time physical activity and mortality from influenza and pneumonia: a cohort study of 577 909 US adults
Objective To examine the association of leisure-time physical activity with mortality from influenza and pneumonia. Methods A nationally representative sample of US adults (aged ≥18 years) who participated in the National Health Interview Survey from 1998 to 2018 were followed for mortality through 2019. Participants were classified as meeting both physical activity guidelines if they reported ≥150 min/week of moderate-intensity equivalent aerobic physical activity and ≥2 episodes/week of muscle-strengthening activity. Participants were also classified into five volume-based categories of self-reported aerobic and muscle-strengthening activity. Influenza and pneumonia mortality was defined as having an underlying cause of death with an International Classification of Diseases, 10th Revision code of J09–J18 recorded in the National Death Index. Mortality risk was assessed using Cox proportional hazards, adjusting for sociodemographic and lifestyle factors, health conditions and influenz
