Table 2.

Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for breast cancer associated with solvent job exposure

		Person-years	Casesa N=1,255 No. (%)	Adjusted HRb, (95% CI)
Solvent job
	Ever	30,386	163 (13)	1.04 (0.88,1.24)
	Never	195,219	1092 (87)	Ref
Total duration of solvent job(s) exposure
	10+ years	12,597	77 (6)	1.14 (0. 90, 1.45)
	5 – <10 years	7,368	36 (3)	0.96 (0.68, 1.35)
	1 – <5 years	10,422	50 (4)	0.98 (0.74, 1.32)
	Never	195,219	1092 (87)	Ref
	Trendc			p=0.35
Frequency of solvent exposure
	1+/week	6,666	37 (3)	0.97 (0.69, 1.37)
	<1/week	23,034	123 (10)	1.07 (0.88, 1.30)
	Never	195,219	1092 (87)	Ref
Time period of first solvent job
	Prior to 1980	14,898	98 (8)	1.16 (0.93, 1.44)
	1980 and after	15,448	65 (5)	0.91 (0.70, 1.18)
	Never	195,219	1092 (87)	Ref
Time since last solvent job at baseline interview
	5+ years	20,177	113 (9)	1.05 (0.86, 1.29)
	Current − <5 years	10,170	50 (4)	1.03 (0.77, 1.38)
	Never	195,219	1092 (87)	Ref
Age at first solvent job at baseline interview
	35+ years	7,328	41 (3)	1.04 (0.76, 1.44)
	25 – <35 years	8,457	42 (3)	0.97 (0.70, 1.34)
	20 – <25 years	7,903	39 (3)	0.95 (0.68, 1.32)
	<20 years	6,658	41 (3)	1.27 (0.92, 1.75)
	Never	195,219	1092 (87)	Ref
	Trendc			p=0.73
Timing of first solvent job
	Prior to first birth	9,613	57 (5)	1.24 (0.95, 1.63)
	After first birth	14,509	75 (6)	0.98 (0.76, 1.26)
	Nulliparous	6,189	31 (2)	0.92 (0.63, 1.33)
	Never	195,219	1092 (87)	Ref
Duration of solvent job(s) exposure relative to first birthd
	5+ years before first birth	3,046	21 (2)	1.42 (0.92, 2.20)
	3 – <5 years before first birth	2,763	18 (2)	1.30 (0.80, 2.10)
	<3 years before first birth	3,804	18 (2)	0.92 (0.57, 1.49)
	After first birth	14,509	75 (7)	0.97 (0.75, 1.25)
	Never	159,720	901 (87)	Ref
	Trendc			p=0.04

^aExcluding 25 cases missing information on date of diagnosis

^bHazard ratios are adjusted for race/ethnicity, education, income, parity, and age at first birth

^cTest for trend among solvent-exposed only

^dAmong parous women only

Note: Differences in the total numbers of cases are due to missing values