Supplementary Material for: The Economics of Cognitive Impairment: Volunteering and Cognitive Function in the HILDA Survey

2016-03-11T00:00:00Z (GMT) by Hosking D.E. Anstey K.J.
Background: The economic impact of older-age cognitive impairment has been estimated primarily by the direct and indirect costs associated with dementia care. Other potential costs associated with milder cognitive impairment in the community have received little attention. Objective: To quantify the cost of nonclinical cognitive impairment in a large population-based sample in order to more fully inform cost-effectiveness evaluations of interventions to maintain cognitive health. Methods: Volunteering by seniors has economic value but those with lower cognitive function may contribute fewer hours. Relations between hours volunteering and cognitive impairment were assessed using the Household, Income and Labour Dynamics in Australia (HILDA) survey data. These findings were extrapolated to the Australian population to estimate one potential cost attributable to nonclinical cognitive impairment. Results: In those aged ≥60 years in HILDA (n = 3,127), conservatively defined cognitive impairment was present in 3.8% of the sample. Impairment was defined by performance ≥1 standard deviation below the age- and education-adjusted mean on both the Symbol Digit Modalities Test and Backwards Digit Span test. In fully adjusted binomial regression models, impairment was associated with the probability of undertaking 1 h 9 min less volunteering a week compared to being nonimpaired (β = -1.15, 95% confidence interval -1.82 to -0.47, p = 0.001). In the population, 3.8% impairment equated to probable loss of AUD 302,307,969 per annum estimated by hours of volunteering valued by replacement cost. Conclusion: Nonclinical cognitive impairment in older age impacts upon on the nonmonetary economy via probable loss of volunteering contribution. Valuing loss of contribution provides additional information for cost-effectiveness evaluations of research and action directed toward maintaining older-age cognitive functioning.