Recalde M, Pistillo A, Fernandez-Bertolin S, et al. - Researchers conducted this population-based cohort study to examine connections between body mass index (BMI) and risk of COVID-19 diagnosis, hospitalisation with COVID-19, and death after a COVID-19 diagnosis or hospitalisation (subsequent death), accounting for potential effect modification by age and gender. Participants in the study were adults (≥ 18 years) with at least one measurement of weight and height. The sample consisted of 2,524,926 participants. BMI was positively linked to being diagnosed and hospitalised with COVID-19. BMI has a monotonic relationship with COVID-19 diagnosis and hospitalisation risks, but a J-shaped relationship with mortality. The increased risk of COVID-19 outcomes was especially noticeable in younger patients.