Mixed
Higher body mass index (BMI) is a strong, linear, and likely causal risk factor for severe COVID-19 outcomes, including hospitalization and death, with risk increasing by approximately 5-10% per kg/m² increase in BMI.
Maintaining a healthy weight is one of the most effective ways to reduce the risk of severe illness from COVID-19. The risk of hospitalization and death increases linearly with BMI. While weight loss is challenging, even modest reductions in weight (e.g., through bariatric surgery or lifestyle changes) have been associated with significantly lower risks of severe outcomes. Public health efforts should prioritize obesity prevention and management as a key strategy to mitigate the impact of the pandemic.
Several hundred studies provide powerful evidence that body mass index (BMI) is a strong linear risk factor for severe COVID-19 outcomes, with recent studies suggesting ~5-10% higher risk for COVID-19 hospitalisation per every kg/m2 higher BMI.
Why this rating
The paper synthesizes hundreds of studies, multiple meta-analyses, large cohort studies (OpenSAFELY, UK Biobank), and Mendelian randomization studies, concluding the evidence is 'overwhelming' and 'powerful'.
Source
Obesity as a Risk Factor for Severe COVID-19: Summary of the Best Evidence and Implications for Health Care
Naveed Sattar et al. · Current Obesity Reports · 2021
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