COHORT EFFECTS IN DISABILITY: IMPLICATIONS FOR MORE DISABILITY IN OLD AGE AND IN RECENT GENERATIONS?

摘要

The goal of this study was to determine a) if the age-trajectory (life course) of disability differs by birth cohort and b) whether any cohort differences are explained by changes in socio-economic status (SES), lifestyle factors, and the presence of chronic conditions. We used biannually collected data from the 1994–2010 Canadian Longitudinal National Population Health Survey: 10,330 participants born from 1925 to 1974 grouped in five 10-year birth cohorts. The outcome was reported disability (needing help with daily living activities or reporting long-term disability). We used multilevel logistic growth models to examine cohort effects in the age-trajectory of disability adjusting for sex, SES (education, income), lifestyle factors (BMI, physical activity, sedentary behavior, smoking status) and multimorbidity (2+ conditions up to 17). We found significant cohort differences in the age-trajectory of disability (p<0.0001): when compared at the same age, each succeeding recent cohort had higher odds of disability than those in the earlier cohort. The age-trajectories were similar for men and women, although women had higher prevalence of disability. Low SES (education and/or income), being smoker, obesity, and multimorbidity were associated with increased odds of having disability. Though attenuated, cohort differences remained significant after accounting for differences in SES, lifestyle factors, and multimorbidity. The results suggest that more recent cohorts of Canadian adults are more likely to have disability and that they report disability earlier than previous generations. This finding has important implications for the organization and planning of healthcare and social services for the disabled population.