Table 1.

Selected characteristics of the cohort included in the present analysis and women meeting similar eligibilty criteria but who did not complete the full 10-year follow-up questionnaire.

	Follow-up cohort		Non-participants
	N	%	N	%
N	40,680	100%	25,165	100%
At baseline
Age at first full-term pregnancy ( yrs)
<25 yrs	12,446	31%	7,311	29%
25–29	12,381	30%	7,453	30%
≥30	6,598	16%	4,377	17%
nulliparous	8,640	21%	5,544	22%
missing	615	2%	480	2%
Family history of breast cancer (1st degree relative)
yes	5,203	13%	3,022	12%
no	34,372	84%	21,069	84%
missing/adopted	1,105	3%	1,074	4%
Average long-term physical activity (hrs/wk)
<1 (inactive)	13,099	32%	8,755	35%
≥1	27,382	67%	16,208	64%
missing	199	1%	202	1%
Alcohol consumption (g/d)
none	12,157	30%	7,980	32%
<20	23,685	58%	13,950	55%
≥20	3,457	9%	1,919	8%
missing	1,381	3%	1.316	5%
At 10-year follow-up
Age (yrs)
≤54	3,467	9%
55–64	18,040	44%
65–74	11,676	29%
75–84	7,497	18%
Body mass index (kg/m2)
<25	20,379	50%
25–29	12,369	30%
≥30	7,516	18%
missing	416	1%
HT use
current	9,249	23%
stopped <5 yrs prior	10,112	25%
stopped ≥5 yrs prior	10,788	27%
never	9,342	23%
missing	1,189	3%
Alcohol consumption (g/d)
none	14,894	37%
<20	18,896	46%
≥20	6,890	17%