Association between multimorbidity patterns and activities of daily living function among older adults in China: a longitudinal population-based cohort study

Background: Older individuals are vulnerable to multiple non-communicable chronic diseases, leading to an increased risk of a decline in activities of daily living (ADLs) disability. Whether this association is affected by sociodemographic factors remains unclear. This study aimed to identify multimorbidity patterns and explore their association with ADLs. Methods: This study included 14,018 older adults (≥ 60 years) from five waves of the China Health and Retirement Longitudinal Study (2011–2020). Multimorbidity patterns were identified among 13 non-communicable chronic diseases using exploratory factor analysis. Associations between multimorbidity patterns and ADLs (basic ADL, BADL; instrumental ADL, IADL) were examined using mixed-effects models. Stratified and interaction analyses were used to explore the influence of sociodemographic factors on these associations. Results: The prevalence of IADL disability among older individuals in China increased from 2011 to 2020.The prevalence of multimorbidity increased steadily from 2011 to 2018 but decreased in 2020. Four multimorbidity patterns were identified: visceral-skeletal, respiratory system, neurodegenerative, and cardiometabolic diseases. Higher factor scores of multimorbidity patterns were associated with increased risk of BADL and IADL disability, particularly for neurodegenerative diseases pattern (T3 vs. T1, BADL: OR 1.44, 95% CI 1.23–1.70; IADL: OR 1.66, 95% CI 1.42–1.94). The positive associations between neurodegenerative diseases and BADL and IADL disability were stronger among urban residents. The inverse associations between cardiometabolic diseases and IADL disability were stronger among educated than illiterate individuals. Conclusion: Multimorbidity was prevalent and independently associated with the risk of a decline in basic and instrumental activities of daily living among older individuals in China. Residential area and education level modified these associations. Trial registration: This study was approved by the Biomedical Ethics Committee of Peking University (NO. IRB00001052-11015).