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Table 4 Hazard ratio and 95% confidence interval of breast cancer according to oolong tea, black tea and coffee intake as assessed by baseline survey

From: Green tea drinking and subsequent risk of breast cancer in a population to based cohort of Japanese women

 

Oolong tea intake

   
 

Less than one cup per week

One to four cups per week

One or more cups per day

 

P for trend

No. of cases

336

153

76

  

Person-years

454,964

148,821

93,630

  

Age- and area-adjusted HR (95% CI)

1.00

1.37

(1.13 to 1.67)

1.09

(0.85 to 1.41)

  

0.08

Multivariate HR (95% CI)*

1.00

1.34

(1.09 to 1.66)

0.98

(0.74 to 1.30)

  

0.40

 

Black tea intake

   
 

Less than one cup per week

One to four cups per week

One or more cups per day

 

P for trend

No. of cases

441

111

24

  

Person-years

557,038

140,312

24,776

  

Age- and area-adjusted HR (95% CI)

1.00

1.00

(0.81 to 1.24)

1.29

(0.85 to 1.96)

  

0.45

Multivariate HR (95% CI)*

1.00

0.84

(0.67 to 1.07)

1.30

(0.84 to 2.02)

  

0.80

 

Coffee intake

 
 

Less than one cup per week

One to four cups per week

One to two cups per day

Three or more cups per day

P for trend

No. of cases

161

180

173

63

 

Person-years

233,697

213,979

210,969

69,940

 

Age- and area-adjusted HR (95% CI)

1.00

1.20

(0.97 to 1.49)

1.18

(0.94 to 1.48)

1.30

(0.95 to 1.77)

0.09

Multivariate HR (95% CI)*

1.00

1.15

(0.91 to 1.46)

1.12

(0.87 to 1.43)

1.22

(0.87 to 1.71)

0.26

  1. * Adjusted for age (continuous), area (10 public health centers), age at menarche (continuous), menopausal status at baseline (premenopausal women, age at menopause for postmenopausal women (-47, 48 to 50, 51 to 53, 54+)), number of births (0, 1, 2, 3, 4, 5+), age at first birth (-21, 22 to 25, 26 to 29, 30+, nulliparous), height (continuous), BMI (continuous), alcohol intake (non-drinkers, occasional drinkers, -150 (g/week) and 150+ (g/week) among regular drinkers (ethanol)), smoking status (never, past, current), leisure time physical activity (no, one to three days per month, more than one day per week), exogenous hormone use (never, past, current), family history of breast cancer (yes, no), green tea intake (less than one cup per day, one to two cups per day, three to four cups per day, five or more cups per day), oolong tea intake (less than one cup per week, one to four cups per week, one or more cups per day), black tea intake (less than one cup per week, one to four cups per week, one or more cups per day) and coffee intake (less than one cup per week, one to four cups per week, one to two cups per day, three or more cups per day). Models for oolong tea, black tea, or coffee intake did not include these variables, respectively.