ABSTRACT

Several epidemiological studies have shown that consumption of coffee and green tea is inversely associated with risks of death and disability; however, the relationship between caffeine consumption and these outcomes remains unclear. We examined these associations in Japanese older adults. This was a prospective study of 7,708 adults (aged ≥65 years) recruited from the Kyoto-Kameoka study. Dietary intake was estimated using a validated food frequency questionnaire. Caffeine consumption was classified into four categories. Disability and mortality data were collected between 15 February 2012 and 30 November 2016. Hazard ratios (HRs) and 95% confidence intervals (CIs) of outcomes were calculated using multivariable Cox proportional hazard models. During the median 4.75-year follow-up period, a total of 593 deaths and 1,379 disability incidents were recorded. After adjusting for confounders, caffeine consumption was inversely associated with the incidence of disability (<100 mg/day: reference; 100-149 mg/day: HR, 0.91 [95% CI, 0.80-1.04]; 150-199 mg/day: HR, 0.84 [95% CI, 0.72-0.99]; ≥200 mg/day: HR, 0.75 [95% CI, 0.63-0.89], p for trend = 0.001) but not all-cause mortality. High coffee consumption was inversely associated with mortality (≥3 cups/day: HR, 0.62 [95% CI, 0.43-0.88]) and disability (≥3 cups/day: HR, 0.81 [95% CI, 0.65-0.99]) compared with non-consumption. However, green tea consumption was not associated with mortality or disability. Caffeine and coffee consumption was inversely associated with disability and/or mortality. Further research is needed to clarify whether high caffeine intake is safe and effective for older adults.

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