Table 1 Characteristic of including studies of green tea intake and incidence risk of esophageal cancer

Gao (1994)

Shanghai China population-based, hostipal-control study

1990-1993

902 (male:622, female: 280) cases and 1552 (male:854, female: 698) hospital-based controls

Male: drinking vs. never drinking 0.80 (0.58-1.09) 1-199g/month vs. never drinking 0.79 (0.53-1.17) >200g/month vs. never drinking 0.79 (0.56-1.13) Female: drinking vs. never drinking 0.50 (0.30-0.83) 1-199g/month vs. never drinking 0.77 (0.39-1.53) >150g/month vs. never drinking 0.34 (0.17-0.69)

Age, education, birthplace, cigarette smoking (both sexes), and alcohol intake (men only).

Yang (1999)

Yangzhong China population-based, case control study

1998-1998

68 cases and 68 population- based controls

drinking vs. never drinking 0.20 (0.06- 0.67)

Age, education, cigarette smoking, and alcohol intake .

Mu (2003)

Taixing, China population-based, case control study

2000-2000

218 cases and 415 hospital based controls

<125g/month vs. never drinking 1.13 (0.67-1.92) 125-250g/month vs. never drinking 0.78 (0.46-1.34) >250g/month vs. never drinking 0.58 (0.35-0.97)

Age, education, cigarette smoking, and alcohol intake .

Astunobu,cohort 1 (2006)

Japan prospective cohort study

9 years

38 cases among 9008 residents in Miyagi prefecture

1-2 cups/day vs. < never or occasionally 0.69(0.17-2.91) 3–4 cups/day vs. < never or occasionally 1.58(0.52-4.76) 5 cups/day vs. < never or occasionally 1.78(0.66-4.82)

Age, sex, cigarette smoking, alcohol consumption, consumption of black tea, coffee

Astunobu,cohort 2 (2006)

Japan prospective cohort s tudy

7.6 years

40 cases among 17715 residents in Miyagi prefecture

1-2 cups/day vs. < never or occasionally 1.22 (0.47-3.19) 3–4 cups/day vs. < never or occasionally 0.85 (0.30-2.40) 5 cups/day vs. < never or occasionally 1.61(0.71-3.66)

Age, sex, cigarette smoking, alcohol consumption, consumption of black tea, coffee

Wang (2007)

China population based case control study

2004-2006

355(male:223, female: 132) cases and 408 (male:252, female: 156) population controls

Male: drinking vs. never drinking 1.37 (0.95–1.98) Female: drinking vs. never drinking 0.26 (0.07–0.94)

Age (continuous), , sex, cancer family history and BMI, marital status and education years. smoking , alcohol drinking.

Wu (2009)

Dafeng China population based case control study

2003-2007

637(male:426, female: 211) cases and 1938 (male:1368, female: 570) Dafeng population controls

<150g/month vs. never drinking 1.0 (0.7-1.3) 125-250g/month vs. never drinking 1.0 (0.6-1.8) >250g/month vs. never drinking 1.0 (0.6–2.0)

Age , gender, education level, income, cancer family history, BMI smoking , alcohol drinking. tea temperature

Wu (2009)

Ganyu China population based case control study

2003-2007

883 (male:765, female: 118) cases and 1941 (male:1548, female: 393) Gany population controls

<150g/month vs. never drinking 1.1(0.7-1.7) 125-250g/month vs. never drinking 1.0 (0.7-1.6) >250g/month vs. never drinking 1.6 (1.1–2.2)

age , gender, education level, income, cancer family history, BMI smoking , alcohol drinking. tea temperature

Chen (2011)

Guangdong China hospital based case control study

2004-2010

150 cases and 300 hospital based controls

<100g/month vs. never drinking 1.27(0.72-1.89) 100-250g/month vs. never drinking 0.97 (0.59-2.56) >250g/month vs. never drinking0.92 (0.49-2.32)

age, sex, education level, annual income, cancer family history, smoking and drinking status

Islami (2009)

Northern Iran population based case control study

2003-2007

266 cases and 386 population- based controls

Daily, weekly vs Never, <weekly 0.65 (0.32 to 1.31)

ethnicity, daily vegetable intake alcohol consumption, tobacco or opium ever use, duration of residence in rural areas,