The cumulative effect of living with disability on mental health in working-age adults: an analysis using marginal structural models

PURPOSE: Previous studies have shown that acquiring a disability is associated with a reduction in mental health, but they have not considered the cumulative impact of having a disability on mental health. We used acquisition of a non-psychological disability to estimate the association of each additional year lived with disability on mental health (measured using the Mental Component Summary score of the Short Form Health Survey). METHODS: We used the first 13 waves of data (years 2001-2013) from the Household, Income and Labour Dynamics in Australia Survey. The sample included 4113 working-age (18-65 years) adults who were disability-free at waves 1 and 2. We fitted marginal structural models with inverse probability weights to estimate the association of each additional year of living with disability on mental health, employing multiple imputation to handle the missing data. RESULTS: Of the 4113 participants, 7.7 percent acquired a disability. On average, each additional year lived with disability was associated with a decrease in the mean Mental Component Summary score (β = - 0.42; 95% CI - 0.71, - 0.14). CONCLUSIONS: This study provides evidence that each additional year lived with non-psychological disability is associated with a decline in mental health among working-age Australians