Green tea and the risk of gastric cancer: Epidemiological evidence

Table 1 Characteristics of epidemiological studies on green tea consumption and stomach cancer risk

Ref.	Region and observation period	Study population1	Green tea consumption levels2	RR or OR (95%CI)3	Direction of association	Adjustments
Case-control studies
Kono et al[28], 1988	Kyushu, Japan, 1979-1982	139 GC cases	≤ 4 cups/d	HC: 0.5 (0.3-1.1)	Inverse (significant) with high consumption	Age, gender, cigarette smoking, mandarin oranges and other fruits
		2574 HC	5-9 cups/d	PC: 0.3 (0.1-0.7)
		278 PC	≥ 10 cups/d
Kato et al[29], 1990	Aichi, Japan, 1985-1989	427 GC cases	1-4 cup/d	Males: 1.01 (0.70-1.47)	None	Age, gender, residence (metropolitan area in Aichi prefecture, other areas of Aichi prefecture, and other prefectures)
		3014 HC	≥ 5 cups/d	Females: 0.81 (0.51-1.27)
Hoyoshima et al[30], 1992	Saitama, Japan, 1984-1990	294 GC cases	≤ 4 cups/d	HC: 1.3 (0.8-2.1)	Minimal to positive	Age, gender, residence, cigarette smoking
		202 HC	5-7 cups/d	PC: 0.8 (0.5-1.3)
		294 PC	≥ 8 cups/d
Yu et al[31], 1995	Shanghai, China, 1991-1993	711 GC cases	Non drinkers	Temperature: 0.71 (0.54-0.93)	Inverse (significant with warm/cold green tea)	Age, education, birthplace, alcohol drinking, cigarette smoking, intake of fresh fruit, vegetables and preserved fruit
		711 matched PC	Drinkers	Boiling hot: 1.18 (0.75-1.86)
				Hot: 0.63 (0.46-0.87)
				Warm/cold: 0.51 (0.29-0.91)
Ji et al[32], 1996	Shanghai, China, 1988-1989	1124 GC cases	Non drinkers	Males: 0.76 (0.55-1.27)	Inverse	Age, income, and education among women; further adjusted for smoking and alcohol drinking among men
		1451 matched PC	Males:	Females: 0.81(0.46-1.43)
			≤ 1200 g/yr
			≤ 2000 g/yr
			≤ 3000 g/yr
			Females:
			≤ 1200 g/yr
			> 1200 g/yr
Inoue et al[33], 1998	Nagoya, Japan, 1990-1995	893 GC cases	Rarely	0.69 (0.48-1.00)	Inverse	Age, gender, year and season at first hospital visit, habitual smoking, habitual alcohol drinking, regular physical exercise, intake of coffee, black tea, fruit, rice and beef
		21128 HC	≥ 7 cups/ d
Setiawan et al[34], 2001	Yangzhong, China, 1995	133 GC cases	Non drinkers	0.39 (0.15-1.01)	Inverse (significant)	Age, gender, body mass index, cigarette smoking, alcohol drinking
		433 PC	1-21 cups/wk
			> 21 cups/wk
Hoshiyama et al[35], 2004	Japan, 1988-1990	157 GC cases	< 1 cup/d	1.20 (0.6-2.5)	None	Age, gender, cigarette smoking, H. pylori infection, history of peptic ulcer, family history of stomach cancer, educational level, consumption of rice, miso soup, green-yellow vegetables, white vegetables, fruits, preference for salty foods
		285 PC	1-2 cups/d
			3-4 cups/d
			5-9 cups/d
			≥ 10 cups/d
Mu et al[36], 2005	Taixing, China, 2000	206 GC cases	Non-drinkers	0.39 (0.17-0.91)	Inverse	Age, gender, education, income, body mass index, cigarette smoking, alcohol drinking, very hot food eating habit, H. pylori infection, stomach disease, family history of stomach cancer
		415 PC	> 250 g/mo
Deandrea et al[37], 2010	Harbin, China, 1987-1989	266 GC cases	Non-drinkers	Temperature: 0.87 (0.60-1.25)	Inverse (significant with lukewarm green tea)	Age, gender, education level, cigarette smoking
		533 HC	< 750 g/ yr	Hot: 1.27 (0.85-1.90)
			≥ 750 g/yr	Lukewarm: 0.19 (0.07-0.49)
Prospective cohort studies
Galanis et al[38], 1998	Hawaii, Unites States, 1975-1994	108 GC cases	Non-drinkers	1.5 (0.9-2.3)	Positive	Age, gender, years of education and Japanese place of birth
		11907 Japanese residents	1 cup/d	Males: 1. 6 (0.9-2.9)
			> 2 cups/d	Females: 1.3 (0.6-2.6)
Nakachi et al[39], 2000	Saitama, Japan	488 GC cases	≤ 3 cups/d	0.59 (0.35-0.98)	Inverse	Cigarette smoking, alcohol drinking, intake of green and yellow vegetables, intake of rice
		8552 adults	4-9 cups/d	Males: 0.54 (0.22-1.34)
			≥ 10 cups/d	Females: 0.57 (0.34-0.98)
Tsubono et al[40], 2001	Miyagi, Japan, 1984-1992	419 GC cases	< 1 cups/d	1.2 (0.9-1.6)	None	Age, gender, type of health insurance, history of peptic ulcer, cigarette smoking, alcohol consumption, consumption of rice, black tea, coffee, meat, green or yellow vegetables, pickled vegetables, other vegetables, fruits and bean-paste soup
		26311 adults	1-2 cups/d	Males: 1.5 (1.0-2.1)
			3-4 cups/d	Females: 0.8 (0.5-1.3)
			≥ 5 cups/d
Nagano et al[41], 2001	Hiroshima Nagasaki, Japan, 1979-1981	901 GC cases	0-1 cups/d	0.95 (0.76-1.2)	None	Age, gender, city of residence, radiation exposure, cigarette smoking, alcohol drinking, body mass index, education level
		37639 adults	2-4 cups/d
			≥ 5 cups/d
Hoshiyama et al[42], 2002	Japan (nationwide), 1988-1997	359 GC deaths	< 1 cups/d	Men: 1.0 (0.5-2.0)	None	Age, smoking, history of peptic ulcer, family history, consumption of rice, miso soup, green-yellow vegetables, fruits and preference for salty foods
		72851 adults	1-2 cups/d	Women: 0.7 (0.3-2.0)
			3-4 cups/d
			5-9 cups/d
			≥ 10 cups/d
Fujino et al[43], 2002	Japan (nationwide), 1988-1990	379 GC deaths	Everyday	Males: 1.11 (0.75-1.63)	None	Age, gender, cigarette smoking, alcohol drinking, diet, sporting activities, medical history, education level
		328030 adults	≤ 3 times/d	Females: 1.43 (0.78-2.62)
			> 3 times/d
Sasazuki et al[44], 2004	Japan (nationwide)	892 GC cases	< 1 cups/d	Males: 0.97 (0.77-1.22)	None	Age, area, cigarette smoking, consumption of fruit, green-yellow vegetables, fish gut, miso soup, rice, black tea and coffee
	Cohort I: 1990-2001	72943 adults	1-2 cups/d	Females: 0.70 (0.47-1.05)
	Cohort II: 1993-1999		3-4 cups/d
			≥ 5 cups/d

¹Number of gastric cancer (GC) cases observed over the study period;

²Frequency of green tea consumption reported in each study;

³Relative risk (RR) or odds ratio (OR) for the highest green tea (GT) consumption level studies. HC: Hospital controls; PC: Population controls; H. pylori: Helicobacter pylori.