Table 1.

Demographic, personal and lifestyle characteristics among breast cancer cases and controls^*, Mayo Clinic, 2001-2005.

Characteristic	Level	Cases n=798		Controls n=843
		N	%	N	%
Age, years	20-39	56	7	48	6
	40-49	192	24	166	20
	50-59	224	28	274	32
	60-69	195	24	207	25
	70+	131	16	148	18
State of residence†	MN	502	63	552	66
	Other	296	37	291	34
Family history ‡	Yes	366	47	345	43
Postmenopausal status	Yes	480	64	579	72
Age at menarche, years	< 12	132	18	122	16
	12	224	31	184	24
	13	218	30	238	32
	≥ 14	154	21	209	28
Postmenopausal hormone use	0 Months	430	58	366	49
	1-60 Months	131	18	160	22
	60+ Months	184	25	216	29
Smoking, packyears	None	467	63	500	66
	≤ 4 years	46	6	67	9
	> 4 years	231	31	192	25
Tumor status
Estrogen receptor	Positive	486	82
	Negative	109	18
Progesterone receptor	Positive	440	74
	Negative	152	26

^*Ns may not total 798 cases and 843 controls due to missing data; Percentages may not total 100 due to rounding.

^†Other refers to IA, IL, WI, ND and SD

^‡Family history in 1^st or 2^nd degree relative with breast or ovarian cancer.