Socioeconomic status and long-term health behaviour maintenance after non-communicable disease diagnosis: a multicohort study.

BACKGROUND: People with lower socioeconomic status (SES) have a higher incidence of non-communicable diseases (NCDs), but socioeconomic differences in the long-term maintenance of health behaviours after NCD diagnosis remain unclear. This study examined whether favourable health behaviours were maintained differently by SES over a 4-year follow-up. METHODS: This prospective multicohort study pooled individual-level longitudinal data from five studies across 17 countries in Europe, the USA and East Asia between 2002 and 2021. Participants who were diagnosed with one or more major NCDs (diabetes, cardiovascular disease, chronic lung disease and cancer) and had favourable behaviours (being physically active and non-smokers, two widely recommended modifiable lifestyle factors) within the first 2 years after the diagnosis (baseline) were included, and were followed up for another 4 years to assess maintenance of health behaviours. SES was constructed using educational level and total household wealth (THW). Logistic regression models were used to analyse pooled multicohort data. RESULTS: A total of 8518 participants were included, of whom 6629 were physically active, 7588 were non-smokers and 5699 were both physically active and non-smokers after the NCD diagnosis. During 4 years of follow-up, 1477 (22.3%) participants failed to maintain physical activity, and 154 (2.0%) became smokers. Educational level, THW and the summed SES score showed dose-response relationships with becoming physically inactive or smokers. For example, compared to participants with the high summed SES score, those with the low score were more likely to become physically inactive (odds ratio [OR]: 3.28, 95% confidence interval [CI]: 2.51-4.28) and smokers (OR: 2.91, 95% CI: 1.36-6.20). This was also seen in those who were both physically active and non-smokers at baseline, with low summed SES score having higher odds of becoming physically inactive but maintaining non-smokers (OR: 3.62, 95% CI: 2.71-4.84). CONCLUSIONS: These findings highlight a pronounced socioeconomic gradient in long-term maintenance of health behaviours after NCD diagnosis, with the low summed SES score more than doubling the risk of becoming physically inactive or smokers within 4 years. Socioeconomic position should be considered in strategies for managing individuals with non-communicable diseases.