Body mass index and fitness in late adolescence and risk of cardiovascular disease, respiratory disease, and overall death after COVID‐19

Abstract Objective Since obesity and poor fitness appear to be unfavorable for both cardiovascular health and coping with viral infections such as COVID‐19, they are of specific interest in light of the increased risk of cardiovascular and respiratory events now seen after infection with SARS‐CoV‐2. Therefore, the aim of the present study was to investigate how body mass index (BMI) and cardiorespiratory fitness (CRF) in late adolescence are associated with the risk of cardiovascular disease (CVD), respiratory disease, and mortality after COVID‐19. Methods In this study, 1.5 million 18‐year‐old Swedish men with BMI and CRF measured during enlistment for military service 1968–2005 were included. Hospitalized and non‐hospitalized COVID‐19 cases were identified through the Patient Register or positive polymerase chain reaction tests, and age‐matched with non‐infected controls. CVD, respiratory disease, and mortality after COVID‐19 were divided into 180days post‐infection. Cox regression models were used. Results Hospitalized COVID‐19 cases (n = 9839), compared to controls, had >10‐fold, 50 to 70‐fold, and >70‐fold hazards of CVD, respiratory disease, and mortality over the initial 60 days post‐infection with little variation across BMI or CRF categories. The elevated risks persisted at declining levels >180 days. For non‐hospitalized COVID‐19 cases (n = 181,822), there was a 4‐ to 7‐fold increased acute mortality risk, and high CRF was associated with lower risk of post‐infectious respiratory disease. Conclusions The high hazards of adverse outcomes during the first two months after COVID‐19 hospitalization, and across BMI and CRF categories, declined rapidly but were still elevated after six months. Adolescent CRF was associated with respiratory disease after COVID‐19 without hospitalization, which gives further support to the health benefits of physical activity.