COFFEE AND PARKINSON’S DISEASE
A review of the scientific literature up to 1 January, 2002 identified 8 case control studies and 5 cohort studies on the relationship between coffee consumption and risk of Parkinson’s disease which met the criteria for inclusion in a meta-analysis (1). This analysis demonstrated that coffee drinkers had 31% less chance of developing Parkinson’s disease than non-coffee drinkers. Hence, the available evidence consistently demonstrates that coffee consumption lowers the risk of Parkinson’s disease.
However, the authors of the review identified a gender difference. When the two cohorts consisting solely of men were considered (2, 3), a strong inverse linear association between cups of coffee consumed and risk of Parkinson’s disease was evident corresponding to a reduction in risk of 49% for every three additional cups of coffee drunk per day. By contrast, the single cohort study consisting solely of women (2) found no association at all. However, a more recent study of 77,713 women, which identified 154 cases of Parkinson’s disease, found that while coffee or caffeine consumption lowered disease risk in women who did not use postmenopausal hormones, they raised disease risk in women who used postmenopausal hormones (4). More studies are needed to decide whether the combined use of oestrogen and coffee or caffeine increases Parkinson’s disease risk.
Research into this debilitating condition continues, with recently published studies supporting the hypothesis that coffee consumption may reduce the risk. A large prospective study consisting of 29,335 Finnish subjects found a reduced risk of Parkinson's disease among habitual coffee drinkers(5). A further study consisting of 6710 men and women, also conducted in Finland, reported similar findings and concluded that 'The results support the hypothesis that coffee consumption reduces the risk of Parkinson's disease, but that the protective effect of coffee may varyby exposure to other factors' (6).
While the available results are encouraging, more research is needed to define the mechanism of action of coffee in protecting against Parkinson’s disease.
References:
1. Hernan, M.A. et al. Annals of Neurology, 52, 276-284, 2002.
2. Ascherio, A. et al. Annals of Neurology, 50, 56-63, 2001.
3. Ross, G.W. et al. Journal of the American Medical Association, 283, 2674-2679, 2000.
4. Ascherio, A. et al. Neurology, 60, 790-795, 2003.
5. Hu, G. et al. Movement Disorders, Online/In Press, August 2007.
6. Saaksjarvi, K. et al. European Journal of Clinical Nutrition, 2007.