Table 2 Hazard ratio estimates of nasopharyngeal cancer in relation to working in job categories.

Job category	Cases	Non‐cases	HR*	95% CI	p for trend
Cotton handing, processing, spinning
Never	52	2589	1.0	Reference
<10 years	4	123	1.9	(0.7 to 5.3)
⩾10 years	11	475	1.3	(0.6 to 2.4)	0.40
Mixed fibre handling processing spinning process
Never	59	2744	1.0	Reference
<10 years	2	126	0.8	(0.2 to 3.6)
⩾10 years	6	317	1.0	(0.4 to 2.3)	0.89
Dyeing
Never	63	3131	1.0	Reference
<10 years	1	19	1.8	(0.2 to 14.1)
⩾10 years	3	37	3.6	(1.0 to 12.1)	0.06
Finishing
Never	65	3147	1.0	Reference
<10 years	1	13	2.6	(0.3 to 21.3)
⩾10 years	1	27	1.6	(0.2 to 12.5)	0.46
Weaving
Never	51	2068	1.0	Reference
<10 years	4	231	0.7	(0.3 to 2.1)
⩾10 years	12	688	0.6	(0.3 to 1.2)	0.12
Printing
Never	64	3162	1.0	Reference
<10 years	2	8	9.2	(1.7 to 48.9)
⩾10 years	1	17	2.0	(0.3 to 16.3)	0.15
Cutting/sewing
Never	59	2892	1.0	Reference
<10 years	2	86	0.9	(0.2 to 3.9)
⩾10 years	6	209	1.3	(0.6 to 3.2)	0.57
Warehouse, packing, quality control
Never	59	2667	1.0	Reference
<10 years	3	182	0.7	(0.2 to 2.1)
⩾10 years	5	338	0.6	(0.3 to 1.6)	0.23

*HR, age adjusted hazard ratio.