Obesity, walking pace and risk of severe COVID-19: Analysis of UK Biobank

Obesity is an emerging risk factor for coronavirus disease-2019 (COVID-19). Simple measures of physical fitness, such as self-reported walking pace, could also be important risk factors, but have not been well documented. This analysis includes 414,201 UK Biobank participants with complete covariate and linked COVID-19 data. We analysed the risk of severe (in-hospital) COVID-19 across categories of obesity status and walking pace. As of June 20^th 2020 there were 972 cases of severe COVID-19 that had occurred within the cohort. Compared to normal weight individuals, the adjusted odds ratio (OR) for severe COVID-9 in those with obesity was 1.49 (1.24, 1.78). Compared to those with a brisk walking pace, the OR in slow walkers was 1.84 (1.49, 2.27). Slow walkers had the highest risk of severe COVID-19 regardless of obesity status. For example, compared to normal weight brisk walkers, the odds of severe COVID-19 in obese brisk walkers was 1.39 (0.99, 1.98), whereas the odds in normal weight slow walkers was 2.48 (1.56, 3.93). Self-reported walking pace, a simple measure of functional fitness, appears to be a risk factor for severe COVID-19 that is independent of obesity. This may help inform simple pragmatic public health risk stratification and preventative strategies.