Personality and incident disability in older persons

Objective: To examine the relation of personality to the development of disability in old age. Methods: Participants are 813 older Catholic nuns, priests and brothers without dementia or disability at study onset. As part of a uniform baseline evaluation, they completed standard measures of the five principal dimensions of personality. Disability was assessed at baseline and annually thereafter with the Katz scale. The relation of each trait to incident disability was assessed in proportional hazard models controlled for age, sex, education and selected clinical variables. Results: During a mean of about 6 years of observation, 255 persons (31%) became dependent on at least one activity of daily living. Risk of becoming disabled was 85% [95% confidence interval (CI) = 80.5-89.6%] lower in persons with high (90th percentile) compared to low (10th percentile) extraversion and 50% (95% CI = 46.6-54.2%) lower in those with high compared to low conscientiousness, and controlling for chronic medical conditions, depressive symptoms or social and cognitive activity did not substantially affect these associations. By contrast, neuroticism had a marginal association with disability risk that was eliminated after controlling for depressive symptomatology, and openness and agreeableness were unrelated to disability risk. Conclusions: The results suggest that higher levels of extraversion and conscientiousness may be associated with a reduced risk of incident disability in old age.