Supplementary Table 1. Definitions of covariates. Covariate Definition UK Biobank Field ID(s) Age Age at accelerometer assessment (years), continuous. 21003, 53, 90010 Sex Female or male. 31 Ethnicity White or non-White. 21000 Education College/university degree or above versus other qualifications. 6138 Townsend deprivation index Area-level socioeconomic deprivation score; higher values indicate greater deprivation. 189 Smoking status Never, former, or current smoker. 20116 Alcohol intake frequency Daily/almost daily, 3-4 times/week, 1-2 times/week, 1-3 times/month, special occasions only, or never. 1558 Body mass index Weight divided by height squared (kg/m2), continuous. 21001