Mushroom Consumption and Incident Dementia in Elderly Japanese: The Ohsaki Cohort 2006 Study

BACKGROUND: Both in vivo and in vitro studies have indicated that edible mushrooms may have preventive effects against cognitive impairment. However, few cohort studies have yet examined the relationship between mushroom consumption and incident dementia. OBJECTIVE: We examined the relationship between mushroom consumption and incident dementia in a population of elderly Japanese subjects. DESIGN: Prospective cohort study. SETTING: Ohsaki Cohort 2006 Study. PARTICIPANTS: 13,230 individuals aged >= 65 years living in Ohsaki City, northeastern Japan. MEASUREMENTS: Daily mushroom consumption, other lifestyle factors, and dementia incidence. RESULTS: The 5.7 years incidence of dementia was 8.7%. In comparison with participants who consumed mushrooms <1 time/wk, the multi-adjusted HRs (95% CI) for incident dementia among those did so 1-2 times/week and >= 3 times/week were 0.95 (0.81, 1.10) and 0.81 (0.69, 0.95), respectively (P-trend <.01). The inverse association persisted after excluding participants whose dementia event occurred in the first 2 years of follow-up and whose baseline cognitive function was lower. The inverse association did not differ statistically in terms of vegetable consumption (P-interaction = .10). CONCLUSIONS: This cohort study suggests that frequent mushroom consumption is significantly associated with a lower risk of incident dementia, even after adjustment for possible confounding factors.