Severity of activity limitation and prevalence of long COVID: a nationally representative cross-sectional study of adults in Scotland

Abstract Background Long COVID is a persistent contributor to population morbidity, and people with disabilities experience substantial and often avoidable health disadvantage worldwide. Whether long COVID is disproportionately reported among adults with current functional limitations is, therefore, a question of health equity, yet nationally representative evidence from the post-emergency phase is limited. We examined the association between severity of current activity limitation and self-reported long COVID among community-dwelling adults in Scotland. Methods We pooled cross-sectional data from the nationally representative 2023 and 2024 Scottish Health Surveys. Participants were adults aged 16 years or older with complete data on activity limitation, long-COVID status, and covariates ( N = 9,312). Activity limitation was classified as none, limited a little, or limited a lot. Survey-weighted logistic regression accounted for calibration weights, stratification, and clustering, and adjusted for age, sex, ethnicity, education, area deprivation, cigarette-smoking status, and survey year. Average marginal predictions estimated adjusted probabilities and absolute differences. Results Survey-weighted long-COVID prevalence was 7.59% (95% CI 6.91–8.34) overall, rising from 4.89% (95% CI 4.21–5.67) among adults without activity limitation to 9.23% (95% CI 7.70–11.04) among those limited a little and 14.42% (95% CI 12.57–16.49) among those limited a lot. Fully adjusted odds ratios were 2.07 (95% CI 1.61–2.65) and 3.26 (95% CI 2.56–4.15), respectively, versus no limitation. The adjusted absolute difference for limited a lot was 9.22 percentage points (95% CI 7.02–11.42), about nine additional cases per 100 adults. Each one-category increase in severity was associated with 81% higher adjusted odds ( P for trend < 0.001). Conclusions Long COVID was substantially more prevalent among adults with greater current activity limitation, and the gradient persisted after adjustment for demographic, socioeconomic, and behavioural characteristics. This contemporaneous concentration of post-viral morbidity identifies a marked functional health inequality. Routine surveillance should retain disability-disaggregated measures of post-viral illness, and health systems should ensure that care for persistent post-COVID symptoms reaches people with current activity limitations rather than being confined to dedicated services. Longitudinal studies are needed to establish temporality.