Prospective study of caffeine consumption and risk of Parkinson's disease in men and women

TLDR

Case‑control and prior prospective studies suggest coffee consumption may lower Parkinson’s disease risk, though the active component remains uncertain. This study examined whether caffeine protects against Parkinson’s disease by analyzing coffee and caffeine intake in the Health Professionals’ Follow‑Up Study and the Nurses’ Health Study. The cohort comprised 47,351 men and 88,565 women free of Parkinson’s disease, stroke, or cancer at baseline, who completed a comprehensive lifestyle and dietary questionnaire that was updated every 2–4 years. During 10–16 years of follow‑up, 288 Parkinson’s disease cases were identified; men in the highest caffeine quintile had a 58% lower risk (RR = 0.42), with inverse associations for coffee, non‑coffee caffeine, and tea, while women exhibited a U‑shaped pattern with lowest risk at moderate intake (1–3 cups/day).

Abstract

Abstract Results of case‐control studies and of a prospective investigation in men suggest that consumption of coffee could protect against the risk of Parkinson's disease, but the active constituent is not clear. To address the hypothesis that caffeine is protective against Parkinson's disease, we examined the relationship of coffee and caffeine consumption to the risk of this disease among participants in 2 ongoing cohorts, the Health Professionals' Follow‐Up Study (HPFS) and the Nurses' Health Study (NHS). The study population comprised 47,351 men and 88,565 women who were free of Parkinson's disease, stroke, or cancer at baseline. A comprehensive life style and dietary questionnaire was completed by the participants at baseline and updated every 2–4 years. During the follow‐up (10 years in men, 16 years in women), we documented a total of 288 incident cases of Parkinson's disease. Among men, after adjustment for age and smoking, the relative risk of Parkinson's disease was 0.42 (95% CI: 0.23–0.78; p for trend < 0.001) for men in the top one‐fifth of caffeine intake compared to those in the bottom one‐fifth. An inverse association was also observed with consumption of coffee ( p for trend = 0.004), caffeine from noncoffee sources ( p for trend < 0.001), and tea ( p for trend = 0.02) but not decaffeinated coffee. Among women, the relationship between caffeine or coffee intake and risk of Parkinson's disease was U‐shaped, with the lowest risk observed at moderate intakes (1–3 cups of coffee/day, or the third quintile of caffeine consumption). These results support a possible protective effect of moderate doses of caffeine on risk of Parkinson's disease.