Table 2.

Hazard Ratios for Type 2 Diabetes and Breast Cancer Risk, Multiethnic Cohort, 1993-2010^a

Characteristic	Category	Cases with T2D	Models without BMI		BMI Included
			HR	95% CI	HR	95% CI
All women		896	1.15	1.07, 1.23	1.08	1.00, 1.16
Postmenopausal women		728	1.16	1.07, 1.25	1.09	1.00, 1.18
Ethnicity	White	116	1.18	0.98, 1.43	1.10	0.90, 1.34
	African American	227	1.18	1.02, 1.37	1.14	0.99, 1.33
	Native Hawaiian	107	0.99	0.80, 1.23	0.93	0.75, 1.16
	Japanese American	239	1.04	0.90, 1.20	0.94	0.82, 1.08
	Latina	207	1.33	1.14, 1.56	1.30	1.11, 1.52
	US-born	130	1.25	1.02, 1.52	1.18	0.96, 1.44
	Foreign-born	77	1.38	1.08, 1.77	1.39	1.08, 1.79
Hormone Receptorsb	ER+/PR+	442	1.17	1.05, 1.29	1.06	0.95, 1.18
	ER−/PR−	107	1.03	0.83, 1.26	1.02	0.83, 1.27
	ER+/PR− and ER−/PR+	132	1.01	0.81, 1.28	1.00	0.79, 1.26
Stageb	In situ	140	1.05	0.87, 1.25	1.02	0.85, 1.22
	Localized	445	1.18	1.06, 1.31	1.11	1.00, 1.24
	Regional/Distant	198	1.28	1.09, 1.50	1.22	1.03, 1.44
BMI status	<20 kg/m2	18	1.17	0.73, 1.89	NA
	20-<25 kg/m2	140	0.97	0.82, 1.16	NA
	25-<30 kg/m2	314	1.05	0.93, 1.18	NA
	≥30 kg/m2	424	1.12	1.00, 1.26	NA
T2D status	Reporting medication	556	1.35	1.24, 1.47	1.27	1.16, 1.38
	No medication	340	0.93	0.83, 1.04	0.88	0.79, 0.98

^aHazard ratios (HR) and 95% confidence intervals (CI) obtained by Cox regression with ethnicity as strata and age as time metric and adjusted for age at cohort entry, education, family history of breast cancer, alcohol intake, physical activity, age at menarche, parity, age at first live birth, postmenopausal hormone use, and ethnicity and BMI depending on the model.

^bStage at diagnosis is missing for 897 breast cancer cases, ER status for 1,487 and PR status for 1,796 cases.