Trends in activities of daily living disability in a large sample of community-dwelling Chinese older adults in Hong Kong: an age-period-cohort analysis

BACKGROUND To examine the trends in activities of daily living (ADL) disability in older Chinese adults in Hong Kong between 2001 and 2012. METHODS Using data from the Elderly Health Centres (EHCs) of the Department of Health comprising a total of 54 808 community-dwelling Chinese adults aged ≥65 years in 1 early cohort (1904-1917) and 10 3-year birth cohorts (1918-1920, 1921-1923, 1924-1926, 1927-1929, 1930-1932, 1933-1935, 1936-1938, 1939-1941, 1942-1944, 1945-1947), we examined trends in ADL disability by using age-period-cohort (APC) models. ADL disability was defined as being unable to perform at least 1 of 7 ADL activities (bathing, dressing, toileting, transferring, feeding, grooming, walking) independently. Cross-classified random-effects logistic regressions were performed for each of the APC trends with adjustment for age, period, cohort, sociodemographic, lifestyle, comorbidity and self-rated health. RESULTS The mean age of the cohort was 70.9±4.7 (range 65-99) years. The prevalence rate of ADL disability was 1.6%. ADL disability increased with age (p<0.001) and the gradient of the increase was steeper in the older age groups. At the same age, women (1.7%) were more likely to report ADL disability than men (1.4%, p=0.001). For both genders, there was an increase in ADL disability between 2003 and 2012; adjustment for age, cohort and other covariates has diminished the trends observed among men. There was no cohort effect in ADL disability. CONCLUSIONS ADL disability in older adults has increased over the last decade. Further study is required to identify possible causes behind the disability trends.