Interaction between economic status and healthy lifestyle in long COVID among Chinese older population: a cross-sectional study

Objectives To estimate the interaction between economic status (ES) and healthy lifestyle in long COVID among Chinese older people infected with SARS-CoV-2.Design A cross-sectional study based on the Peking University Health Cohort in Anning, Yunnan.Setting All primary health institutions in Anning, Yunnan Province, China, from April to May 2023.Participants A total of 4804 people aged 60 and older infected with SARS-CoV-2 were included in this study.Primary and secondary outcome measures Long COVID was measured by participants’ self-reported symptoms using structured questionnaires. ES was measured by last-month personal income, and participants’ ES was defined as low if their income was below the per capita monthly income of local residents. Lifestyle score was equal to the number of healthy behaviours (including smoking, drinking, weight, exercise and diet) and grouped using the median score as the cut-off point. Univariate and multivariate logistic models were employed to estimate the association of ES with long COVID. Interaction between ES and lifestyle in long COVID was assessed by multiplicative interaction term.Results We enrolled a total of 4804 participants infected with SARS-CoV-2, of whom 57.3% (2754 of 4804) had at least one long COVID symptom. Fatigue (1546, 56.1%), cough (1263, 45.9%) and muscle pain (880, 32.0%) were the top three common symptoms. Patients with low ES had a 48% (adjusted OR: 1.48; 95% CI 1.22, 1.82) increased risk of long COVID. A significant interaction was observed between ES and lifestyle (p value for interaction