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

Table 1

Tea drinking and PD risk.

Author	Year of publication	Country	Cases		Controls		Relative risk	95% CI
			𝑁	𝑛	𝑁	𝑛
Haack et al. [8]	1981	USA	237	223	474	456	0.63	[0.31, 1.29]
Ho et al. [9]	1989	China	34	21	105	70	0.81	[0.36, 1.80]
Fall et al. [10]	1999	Sweden	113	64	263	174	0.67	[0.43, 1.05]
Preux et al. [11]	2000	France	140	40	280	54	1.67	[1.04, 2.68]
Paganini-Hill [12]	2001	USA	395	182	2320	1126	0.91	[0.73, 1.12]
Morano et al. [13]	1994	Spain	74	6	148	6	2.09	[0.65, 6.71]
Chan et al. [14]	1998	China	215	113	313	196	0.66	[0.46, 0.94]
Checkoway et al. [15]	2002	USA	210	72	347	145	0.73	[0.51, 1.04]
Total			1418		4250		0.85	[0.74, 0.98]

Test for heterogeneity among all studies: 𝑄=15.03 based on 7 degrees of freedom 𝑃=0.04. Summary OR was based on fixed effect models. 𝑁∶ number of cases/controls, 𝑛∶ number of tea drinkers in cases/controls.