Association between Six Environmental Chemicals and Lung Cancer Incidence in the United States

Table 1

Characteristics of 215 counties by levels of release of selected chemicals*.

Variable^†	No release	Low release	High release	𝑃 value
𝑁 of counties	147	38	30	NA
Proportion of nonwhite population (%)	7.7	9.4	12.8	0.3
Proportion of males (%)	49.0	48.9	49.8	0.004
Less than high school (%)	24.5	22.3	20.3	0.03
College or higher education (%)	14.3	16.9	22.4	<0.0001
Families below poverty (%)	11.9	9.6	8.3	0.005
Unemployed rate (%)	5.7	5.4	6.1	0.6
Prevalence of smoking	18.5	18.1	18.0	0.8
Nonmetro counties (%)^‡	130 (88.4%)	26 (68.4)	9 (26.7)	<0.0001

*The cut point for low or high release of total amount of selected chemicals was set at 2000 pounds annually (low: <2000 pounds, high: ≥2000 pounds). ^†All county attributes were in year 1990 except for prevalence of smoking, which was in year 2003–2006. ^‡Metro or nonmetro counties (metro counties: Rural-Urban Continuum Code < 4; nonmetro counties: Rural-Urban Continuum Code ≥ 4).