[Relationship between Quality of Life (QOL) and cognitive function among community-dwelling elderly]

It has become important for elderly to live better rather than to live longer. There have been many reports about quality of life (QOL) of the elderly, but we have no knowledge about the relation between the QOL and the cognitive function. We investigated the relationship between the QOL and the cognitive function among community-dwelling elderly.

A total of 12,059 community-dwelling elderly were invited to join a cognitive screening study by telephone (TICS-J) combined with a mailed QOL questionnaire. Among them, 1,920 subjects (age 71.87+/-5.50 (mean+/-SD) years old, duration of education 11.08+/-2.61 years) who completed both TICS-J and QOL questionnaire were actually measured. TICS-J was administered by the previously reported method, and the QOL questionnaire was developed based on the component of QOL proposed by Lawton, and consisted of 6 subscales (daily activity, satisfaction with health, satisfaction with human support, satisfaction with economic state, symptoms of depression, and positive mental attitude). Correlations were analyzed among the scores of TICS-J, age, duration of education, and scores on each QOL subscale. Multiple linear regression analysis was conducted after QOL subscale scores, adjusting for gender, age, and duration of education, were entered as dependent variables.

Four out of 6 subscales scores of QOL showed significant differences between men and women. All QOL subscale scores showed significant differences between the two groups in the TICS-J scores. Partial correlations were seen among TICS-J scores and each QOL subscale score. Multiple linear regression analysis revealed significant influence of cognitive function by TICS-J on QOL subscales scores.

Cognitive function was considered to have more influence on QOL scores than gender or age. TICS-J and the QOL questionnaire in this study were useful to evaluate the outcome of welfare in community-dwelling elderly.