Mini-Mental State Examination score trajectories and incident disabling dementia among community-dwelling older Japanese adults

Aim: The present prospective study used repeated measures analysis to identify potential Mini-Mental State Examination (MMSE) score trajectories and determine whether MMSE trajectory was associated with incident disabling dementia among community-dwelling older Japanese adults.

Methods: A total of 1724 non-demented adults (mean age 71.4 years [SD 5.7]; 56.7% women) aged 65-90 years participated in annual geriatric health assessments during the period from June 2002 through July 2014. The total number of observations was 6755, and the average number of follow-up assessments was 3.9. A review of municipal databases in the Japanese public long-term care insurance system showed that 205 (11.9%) participants developed disabling dementia through December 2014.

Results: We identified three distinct MMSE score trajectory patterns (high, middle and low) in adults aged 65-90 years. After adjusting for important confounders, participants with middle (42.8%) and low (5.1%) MMSE trajectories had hazard ratios of 2.46 (95% confidence interval 1.64-3.68) and 10.73 (95% confidence interval 4.91-23.45), respectively, for incident disabling dementia, as compared with those in the high (52.1%) trajectory group.

Conclusions: Approximately half of the participants were classified as having a high MMSE trajectory, whereas 43% and 5% had middle and low MMSE trajectories, respectively, in this population. Individuals with middle and low MMSE trajectories had a higher risk for incident disabling dementia, which suggests that a high-risk approach to dementia prevention should target people with mild and more rapid cognitive decline. Geriatr Gerontol Int 2017; 17: 1928-1935.