Table 3

Categorical analysis of the effect of duration of exposure, irrespective of intensity, to organic solvents and extremely low frequency magnetic fields, assessed for each subject individually, on the risk for Ph+CML

Exposure and duration	Cases (n)	Controls (n)	OR	95% CI
Organic solvents (y):^3-150
Zero	146	175	1.0
1–7	9	13	0.88	0.34 to 2.3
8–14	11	13	1.0	0.41 to 2.3
15–20	35	25	2.1	1.1 to 4.0
Uncertain	25	25	1.2	0.65 to 2.1
Electromagnetic fields (y):^3-151
Zero	151	182	1.0
1–7	10	13	1.1	0.44 to 2.6
8–14	10	14	0.83	0.33 to 2.1
15–20	35	22	2.3	1.2 to 4.5
Uncertain	20	20	1.4	0.71 to 2.7

↵3-150 Subjects with both hobby and occupational exposure were classified according to the exposure of longest duration.
↵3-151 Only occupational exposure was assessed.