The relationship between health and cognitive functioning in a sample of elderly people in the community.

The association between health status and cognitive performance was examined in a sample of 708 community dwelling elderly people aged 70 years or over. Cognitive performance declined significantly across the age groups 70-74, 75-79, 80-84, and 85-89 years on the Mini-Mental State Examination and on measures of fluid intelligence and memory, but not on measures of crystallized intelligence. Health status declined significantly across age for five of 49 past and current medical conditions, for measures of Activities of Daily Living (ADL) and for systolic blood pressure, but did not decline significantly for global self-ratings of health, diastolic blood pressure or reports of smoking. Weak but significant correlations between health and cognitive performance were found for self-reported global ratings of health and for self-reports of some physical symptoms but not for diastolic or systolic blood pressure, or for many other physical conditions. Both self- and informant-based ratings of ADL correlated with cognitive performance. Age differences remained after cognitive performance was adjusted for health variables such as ADL, self-ratings of health and current health problems. It is concluded that, at the population level, lower levels of cognitive performance in community-dwelling elderly subjects are not strongly mediated by ill health.