Manganese and Extracellular Superoxide Dismutase Polymorphisms and Risk for Asbestosis

Table 1

Smoking and cumulative asbestos exposure in cases and controls.

	Cases (𝑛=262)			Controls (𝑛=265)			Test	P-value
Smoking (ever/never smokers, n)	117/145			120/145			𝜒^2=0.01	.919
	Mean	SD	Range	Mean	SD	Range
Years of smoking	25.92	13.37	0.01–60.00	22.90	12.90	1.00–61.00	𝑡=1.77	.078
Pack-years of smoking	21.92	15.95	0.15–66.25	20.99	16.37	0.05–90.00	𝑡=0.44	.659
Cumulative asbestos exposure (fibres/cm^3-years)	37.67	86.43	0.01–869.72	11.23	23.47	0.01–149.21	𝑡=4.78	.000