Table 2.

Characteristics of pooled indoor air pollution study population.

	Cases (n = 5,105)		Controls (n = 6,535)
Characteristic	n	%	n	%	p-Valuea
Sex					< 0.0001
Men	3,176	62.2	3,600	55.1
Women	1,926	37.7	2,935	44.9
Age (years)					< 0.0001
< 50	875	17.1	1,553	23.8
50–60	1,878	36.8	2,330	35.7
> 60–70	1,584	31.0	1,664	25.5
> 70	768	15.0	998	15.3
Race/ethnicity					< 0.0001
White	3,825	74.9	4,412	67.5
Asian	1,059	20.7	1,544	23.6
Other	221	4.3	579	8.9
Education					< 0.0001
Low (0–9 years)	1,302	25.5	1,871	28.6
Medium (10–15 years)	2,795	54.8	2,981	45.6
High (≥16 years)	1,008	19.7	1,683	25.8
Smoking status					< 0.0001
Ever	4,116	80.6	3,524	53.9
Never	989	19.4	3,011	46.1
Geographic region					< 0.0001
North America	1,329	26.0	2,226	34.1
Asia	921	18.0	1,380	21.1
Europe	2,855	55.9	2,929	44.8
Fuel type predominantly used					< 0.0001b
Nonsolid fuels (electric, oil, gas)	1,548	30.3	2,732	41.8
Solid fuels (coal, wood)	3,557	69.7	3,803	58.2
Coal only	1,943	38.1	1,945	29.8
Wood only	1,080	21.2	1,172	17.9

^aChi-square test.

^bComparing nonsolid-fuel users and solid-fuel users.