Table 3

Odds ratios for rheumatoid arthritis by each exposure variable (conditional logistic regression analysis)

Exposure index		All				Men			Women
Exposure index		Unadjusted	Adjusted^3-150			Unadjusted	Adjusted^3-151		Unadjusted	Adjusted^3-152
Duration/10 (y):
OR	0.31	0.31		0.27	0.29		0.36	0.61
95% CI	0.16 to 0.60	0.16 to 0.61		0.11 to 0.68	0.11 to 0.76		0.13 to 0.98	0.18 to 2.02

Cumulative exposure/1000 (μg/m³×y):
OR	0.81	0.80		0.73	0.71		0.96	1.13
95% CI	0.64 to 1.02	0.64 to 1.02		0.54 to 0.99	0.52 to 0.97		0.66 to 1.38	0.73 to 1.73

Mean silica concentration/100 (μg/m³):
OR	0.99	0.97		0.89	0.79		1.49	1.56
95% CI	0.58 to 1.73	0.56 to 1.70		0.47 to 1.68	0.40 to 1.57		0.47 to 4.68	0.36 to 6.75
Cases (n)	58	58		43	43		15	13

↵3-150 Adjusted for ever or never smoking.
↵3-151 Adjusted for ever or never smoking + history of working in the coal mining industry.
↵3-152 Adjusted for ever or never smoking + number of children.