Table 1.

Characteristics of 736 cases by menopausal status from the Polish Breast Cancer Study

	Premenopausal cases N = 142		Post-menopausal cases N = 594
	Mean	SD	Mean	SD
Age, years	44.9	5.7	61.2	7.9
Age at menarche, years	13.0	1.7	13.6	1.7
Age at first birth, years	24.3	4.8	24.1	4.6
Age at menopause, years	–	–	49.7	4.7
Parous, frequency†	128	90.1	501	84.3
Family history of breast cancer, frequency†	14	9.9	69	11.6
History of benign breast disease, frequency†	35	24.7	105	17.7
HRT use, frequency†	–	–	148	24.9

^†Frequencies represented as N and percent instead of mean and SD