Table 3.

Odds of silica-type PMF versus non-silica- type (ie, mixed-type or coal-type) PMF

	Crude			Adjusted*
	OR	95% CI		OR	95% CI
Year of birth†	1.18	1.04	1.34	1.22	1.02	1.45
Age at death	0.98	0.95	1.02	1.02	0.98	1.07
Years of underground coal mining	0.97	0.95	1.00	0.98	0.95	1.01
Region worked
Central Appalachia‡	1.11	0.62	2.02	0.98	0.52	1.86
Rest of USA	Ref			Ref

^*Adjusted ORs and CIs are derived from a multivariate logistic regression model that includes all covariates listed in the table.

^†Every 5 years after 1885.

^‡Central Appalachia includes Kentucky, Virginia and West Virginia.

PMF, progressive massive fibrosis.