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

Breast Cancer Research

Table 3 Hazard ratio and 95% confidence interval of breast cancer according to subgroup analyses

	Green tea intake assessed by baseline questionnaire
	Less than one cup per day	One to two cups per day		Three to four cups per day		Five or more cups per day		P for trend
All subjects
No. of cases	154	117		160		150
Age- and area-adjusted HR (95% CI)	1.00	1.01	(0.79 to 1.29)	1.08	(0.86 to 1.36)	1.02	(0.81 to 1.30)	0.75
Multivariate HR (95% CI)*	1.00	1.04	(0.80 to 1.35)	1.08	(0.84 to 1.39)	1.03	(0.80 to 1.34)	0.76
ER+PR+ breast cancer
No. of cases	29	25		32		32
Age- and area-adjusted HR (95% CI)	1.00	1.25	(0.73 to 2.17)	1.18	(0.69 to 2.00)	1.05	(0.62 to 1.79)	0.93
Multivariate HR (95% CI)*	1.00	1.33	(0.75 to 2.38)	1.35	(0.77 to 2.36)	1.02	(0.57 to 1.83)	0.92
ER- PR- breast cancer
No. of cases	23	16		20		16
Age- and area-adjusted HR (95% CI)	1.00	1.10	(0.58 to 2.11)	1.09	(0.58 to 2.05)	0.82	(0.42 to 1.60)	0.61
Multivariate HR (95% CI)*	1.00	1.13	(0.55 to 2.32)	1.23	(0.63 to 2.41)	0.81	(0.39 to 1.69)	0.69
Premenopausal women
No. of cases	81	59		71		51
Age- and area-adjusted HR (95% CI)	1.00	1.01	(0.72 to 1.43)	1.13	(0.81 to 1.58)	0.95	(0.66 to 1.37)	0.99
Multivariate HR (95% CI)*	1.00	1.05	(0.73 to 1.49)	1.12	(0.79 to 1.58)	0.97	(0.66 to 1.41)	0.99
Postmenopausal women
No. of cases	70	56		86		96
Age- and area-adjusted HR (95% CI)	1.00	1.01	(0.71 to 1.45)	1.04	(0.75 to 1.45)	1.05	(0.76 to 1.45)	0.76
Multivariate HR (95% CI)*	1.00	1.01	(0.67 to 1.50)	1.02	(0.71 to 1.48)	1.08	(0.75 to 1.55)	0.67

* 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), 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).

ISSN: 1465-542X