The neuroprotective effects of caffeine: a prospective population study (the Three City Study)

To examine the association between caffeine intake, cognitive decline, and incident dementia in a community-based sample of subjects aged 65 years and over.

Participants were 4,197 women and 2,820 men from a population-based cohort recruited from three French cities. Cognitive performance, clinical diagnosis of dementia, and caffeine consumption were evaluated at baseline and at 2 and 4 year follow-up.

Caffeine consumption is associated with a wide range of sociodemographic, lifestyle, and clinical variables which may also affect cognitive decline. Multivariate mixed models and multivariate adjusted logistic regression indicated that women with high rates of caffeine consumption (over three cups per day) showed less decline in verbal retrieval (OR = 0.67, CI = 0.53, 0.85), and to a lesser extent in visuospatial memory (OR = 0.82, CI = 0.65, 1.03) over 4 years than women consuming one cup or less. The protective effect of caffeine was observed to increase with age (OR = 0.73, CI = 0.53, 1.02 in the age range 65 to 74; OR = 0.3, CI = 0.14, 0.63 in the range 80+). No relation was found between caffeine intake and cognitive decline in men. Caffeine consumption did not reduce dementia risk over 4 years.

The psychostimulant properties of caffeine appear to reduce cognitive decline in women without dementia, especially at higher ages. Although no impact is observed on dementia incidence, further studies are required to ascertain whether caffeine may nonetheless be of potential use in prolonging the period of mild cognitive impairment in women prior to a diagnosis of dementia.