A Meta-Analysis of Tea Drinking and Risk of Parkinson's Disease

Table 2

The dose effect relationship of tea drinking and PD risk.

Author	Year of publication	Country	Cases		Controls		Relative risk	95% CI
			𝑁	𝑛	𝑁	𝑛
Drinkers of ≤1 cup per day of tea versus non-consumers studies
Fall et al. [10]	1999	Sweden	113	57	263	143	0.85	[0.55, 1.33]
Paganini-Hill [12]	2001	USA	395	132	2320	892	0.80	[0.64, 1.01]
Checkoway et al. [15]	2002	USA	210	61	347	110	0.88	[0.61, 1.28]
Total			718		2930		0.83	[0.69, 0.99]
Drinkers of >1 cups per day of tea versus non-consumers studies
Fall et al. [10]	1999	Sweden	113	7	263	31	0.49	[0.21, 1.16]
Paganini-Hill [12]	2001	USA	395	50	2320	234	1.29	[0.93, 1.79]
Checkoway et al. [15]	2002	USA	210	11	347	35	0.49	[0.24, 0.99]
Total			718		2930		0.96	[0.73, 1.27]

𝑁: number of cases/controls, 𝑛: number of tea drinkers in cases/controls.