Diseases and impairments as risk factors for onset of disability in the older population in England and Wales: findings from the Medical Research Council Cognitive Function and Ageing Study

BACKGROUND: This paper reports the association between self-reported diseases and impairments and 2-year onset of disability in a prospective study of people aged 65 years or older in five urban and rural centers in England and Wales (Medical Research Council Cognitive Function and Ageing Study; MRC-CFAS). METHODS: We initially reviewed risk factors for onset of disability in 35 prospective studies of functional decline in older people published in 1998-2001. In the present study, disability was defined as requiring help from another person at least several times a week and was assessed by dependency in activities of daily living. Polytomous and bivariate logistic regression models were fitted for onset of disability and mortality among those nondisabled at baseline (n=7913), adjusting for age, sex, and sociodemography. RESULTS: Among prevalent conditions, arthritis (population-attributable risk 11.4%) and cognitive impairment indicated by a Mini-Mental State Examination score of