Modifiable risk factors affect SARS-CoV-2 infection and mortality raising the possibility that lifestyle modification could play a role. This has not been studied at a global level. We analysed publicly available data from countries reporting COVID-19 cases and deaths. Associations of modifiable risk factors with total cases and excess deaths were determined with and without adjustment for confounders. 4,670,832 cases and 311,384 deaths were reported by 181 countries by 18th May 2020. Wealthier countries had the greatest caseload. Obesity was the primary modifiable risk factor for infection and greater age, male sex, physical inactivity and low salt consumption were associated with excess deaths. Obesity was less influential on mortality than physical inactivity. Globally, obesity confers vulnerability to SARS-CoV-2 infection and physical inactivity likely explains the greater mortality in the obese. High salt consumption may induce reductions in tissue ACE2 expression and subsequently reduce mortality rates.