Risk Factors for Premenopausal Breast Cancer in Bangladesh

Table 2

Conditional logistic regression analysis to estimate the odds (odds ratios, OR) of breast cancer.

Characteristic	Cases	Controls	Unadjusted OR			Adjusted OR
			OR	95% CI		OR	95% CI
Reproductive factors
Age at menarche, mean	11.5	12.0	1.81	1.33–2.45	0.0001	1.67	1.09–2.56	0.02
Age at first childbirth, mean	20.8	22.3	1.08	1.01–1.16	0.03	1.03	0.94–1.13	0.48
Parity, mean	2.2	2.1	0.96	0.78–1.17	0.68	1.11	0.78–1.56	0.56
Anthropometric factors
Weight gain, mean	13.0	8.9	1.13	1.07–1.20	0.0001	1.07	0.97–1.19	0.18
BMI at the age of 18 years, mean	18.1	18.6	1.06	0.96–1.17	0.24	1.02	0.78–1.32	0.91
Current BMI (kg/m^2)
≤18.5	5 (4%)	4 (3%)	1.53	0.39–6.01	0.42	0.50	0.04–6.34	0.59
18.5–24.99	89 (69%)	116 (90%)	1			1
≥25	35 (27%)	9 (7%)	7.61	2.68–21.64	0.003	5.24	1.10–24.9	0.04
Socioeconomic factors
Income (Bangladeshi taka per month), mean	3,454	4,370	1.00	1.00-1.00	0.21	1.00	1.00-1.00	0.77
Education
≥grade 11	12 (9%)	40 (31%)	1			1
None or ≤grade 10	115 (89%)	87 (67%)	4.11	1.98–8.52	0.0001	5.26	1.54–17.99	0.008

BMI, body mass index; OR, odds ratio; CI, confidence interval.
For cases: mean weight gain (kg) from the age of 18 years to weight at breast cancer diagnosis; for controls: mean weight gain (kg) from the age of 18 years to weight at the date of interview.
Current BMI (kg/m²): for cases, current BMI was BMI at the time of breast cancer diagnosis; for controls, current BMI was BMI at the time of interview.