Grand Rounds

Does Coffee Consumption Reduce Dementia Risk?

BACKGROUND AND PURPOSE:

Consumption of coffee or caffeine may help prevent dementia, possibly by reducing amyloid-β (Aβ) in the brain
- Data is currently limited
Matsushita et al. (Journal of the American Geriatrics Society, 2021) examined association between caffeine consumption and dementia risk

Cohort study
- Murakami cohort study targeted all residents between 40 and 74 years, living in Murakami city, Sekikawa village, and Awashimaura village of Niigata Prefecture in Japan
Participants
- Adults aged 40 to 74 years
- Japanese Cohort
Exposures
- Consumption levels of coffee or green tea
Study design
- Caffeine consumption was estimated from self-reported amount of coffee or green tea consumption
- Incidence of primary outcome was determined from a long-term care insurance database
- Covariate Analyses: Demographic factors | BMI | Physical activity | Energy | Smoking | Drinking | Disease history
- Adjusted hazard ratio (HR) calculated using Cox proportional hazards models
Primary outcome
- Incident dementia

13,757 participants
- Follow-up: 8.0 years
- Dementia cases during the study period: 309
Compared to participants who consumed <26 ml (0.9 oz) of coffee per day (1^st quintile), those that consumed ≥326 ml (11 oz) per day (5^th quintile) had reduced dementia risk
- HR 0.49 (95% CI, 0.30 to 0.79)
- Adjusted p for trend=0.0014
- In subgroup analysis
  - Overall significant among men, not women
  - Among ≥60 years, 5^th quintile had lower HR (0.5; 95% CI, 0.29 to 0.85) for both men and women
Compared to those who did not consume coffee, higher cups per day was associated with reduced dementia risk in men and women combined
- 2 to 2.9 cups/day: HR 0.69 (95% CI, 0.48 to 0.98)
- ≥3 cups/day: HR 0.53 (95% CI, 0.31 to 0.89, respectively
Participants with higher caffeine consumption had a significantly lower HR than those who consumed <92 mg per day
- adjusted p for trend=0.0004
There was no association between green tea consumption and reduced dementia risk overall but marginal significance seen in the 60 to 69 years age subgroup

Higher levels of daily coffee and caffeine intake were dose-dependently associated with reduced dementia risk, especially among men
Authors suggest possible reasons for differences between men and women
- Men have a higher degree of oxidative stress and benefits of caffeine may include antioxidant effect
- Effects of caffeine on sex hormones may differ by sex

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