Breast cancer risk in relation to occupations with exposure to carcinogens and endocrine disruptors: a Canadian case–control study

Table 3 Descriptive statistics for breast cancer cases and controls

	Controls	Cases
n	1146	1006
Age @ interview, years, mean	56.2	60.0
Year @ interview (controls),or diagnosis (cases), mean	2006.3	2005.8
Never pregnant, %	11.9	11.9
Number of full-term pregnancies, mean	2.83	2.84
Duration fecundity, year, mean	32.2	33.9
Total breastfeeding, mo, mean	5.8	4.9
Education < HS, %	13.3	23.6
Education = HS or some college, %	40.1	38.7
Education > HS and some college, %	46.6	37.7
Family annual income < $40,000, %	31.3	46.8
Family income >= $40,000 and bluecollar, %	22.5	17.5
Family income >= $40,000 and whitecollar, %	46.2	35.7
Pack-years of smoking (lagged 5 year), mean	6.39	7.52
Duration employed (lagged 5 year), year, mean	25.7	25.5
Cumulative exposure in Major Sectors ¹
Farming, mean	7.19	12.06
Non-plastic light mfg, mean	1.21	1.39
Petrochemical, mean	0.12	0.12
Plastics mfg, mean	1.99	4.13
Metalworking, mean	2.33	4.50
Transportation, mean	0.88	0.71
Beauty care, laundry/dry cleaning, mean	0.39	0.39
Bars-gambling, mean	0.11	0.17

1 cumulative exposure on transformed ratings: 1 (low), 2 (moderate), 3 (high) → 0, 1, 10, as rating-year.