Table 1.

Characteristics of the study subjects

Characteristic	Cases (n = 237)	Controls (n = 185)	Chi-square	P value
Age *
< 45 years	53	38
≥ 45 years	184	147	0.20	0.65
Body mass index
< 22 kg/m2	126	99
≥ 22 kg/m2	111	86	0.005	0.94
Age at menarche
< 14 years	113	92
≥ 14 years	124	93	0.17	0.68
Age at first birth
< 25 years	96	67
≥ 25 years	112	98
No birth	29	20	1.36	0.51
Number of births
< 2	56	43
≥ 2	181	142	0.009	0.93
Menopause state
Premenopause	134	71
Postmenopause	103	114	13.72	< 0.001
Alcohol
< 1 day/week	184	148
≥ 1 day/week	53	37	0.35	0.56
Smoking
Noncurrent	211	169
Current	26	16	0.63	0.43
Family history of breast cancer (mother and /or sisters)
No	207	173
Yes	30	12	4.42	0.04

^* Age at diagnosis for cases and at study enrollment for controls.