Table 3.

Exposure to organic dust and lung cancer risk

Subjects	Cumulative exposure to organic dust	Cases	Controls	OR^*	95% CI
All	Never	6,487	8,940	1.00	Reference
	1^st Quartile	1,549	1,770	1.05	0.96–1.15
	2^nd Quartile	1,875	1,914	1.15	1.06–1.25
	3^rd Quartile	1,634	1,804	1.12	1.03–1.22
	4^th Quartile	1,755	1,845	1.24	1.14–1.35
	Test for trend, p-value^†			<.001
Never smokers	Never	487	2,971	1.00	Reference
	1^st Quartile	105	498	0.98	0.76–1.26
	2^nd Quartile	128	576	1.07	0.84–1.35
	3^rd Quartile	129	540	1.20	0.95–1.51
	4^th Quartile	115	592	0.98	0.76–1.25
	Test for trend, p-value^†			0.440
Workers never employed in a ‘list A job’	Never	6,018	8,598	1.00	Reference
	1^st Quartile	1,335	1,586	1.06	0.97–1.17
	2^nd Quartile	1,607	1,694	1.19	1.09–1.30
	3^rd Quartile	1,397	1,604	1.14	1.04–1.24
	4^th Quartile	1,576	1,706	1.25	1.14–1.36
	Test for trend, p-value^†			<.001

ORs are adjusted for age, sex, study, cigarette pack-years, time-since-quitting smoking (where appropriate), and ever employment in a ‘list A job’

^†

P-values for trend result from logistic regression model with exposure as continuous variable