Prevalence and characteristics of older community residents with mild cognitive decline

Abstract

Background: Cognitive impairment is a major health issue, but epidemiological data on mild cognitive decline have been almost absent in Japan.Methods: Of all residents aged 65 years and over living in Yoita town, Niigata Prefecture, Japan in the year 2000 (n = 1673), 1544 participated in the interview survey held at community halls or at home (92.3% response). They underwent the Mini‐Mental State Examination (MMSE) for assessment of cognitive function and answered questionnaires comprising socio‐demographic, psychological, physical and medical, and social activity items. Higher‐level functional capacities were evaluated with the Tokyo Metropolitan Index of Competence (TMIG‐Index of Competence). According to subject’s age and MMSE score, all subjects were classified into 3 groups: control (MMSE > 1 SD below age‐specific means), mild cognitive decline (MMSE ≥ 21 and ≤ 1 SD below age‐specific means), and severe cognitive decline (MMSE ≤ 20), and compared various characteristics among these groups.Results: Mean MMSE score of the subjects showed a linear decline with advancing age. Among the participants, 232 (15.2%) were classified as mild cognitive decline. Compared with the controls, the subjects with mild cognitive decline reported poorer subjective health, more depressive moods, more history of stroke, more prevalence of basic activity of daily living (BADL) disability, and lower higher‐level functional capacity, even after controlling for possible confounding factors. They also reported a low level of social activities: both participating in group activities and enjoying hobbies were less frequent. Their food intake pattern tended to be monotonous.Conclusions: Older persons with mild cognitive decline comprised a substantial proportion (15.2%) of the community‐dwelling older population. In addition to lower cognitive function, they had lower levels of functional capacity and social activity.