Table 1.

Summary of case–control studies pooled for indoor air pollution analysis.^a

Study sponsor (study name)	Principal investigator	Country of study	Study period	Control source	Cases	Controls	Participation rate (%)
							Cases	Controls
North American and European studies
Central and Eastern Europe (CEE)	P. Boffetta	Central and Eastern Europe	1998–2002	Hospital based	2,861	2,936	84	85
University of California–Los Angeles (California)	Z.F. Zhang	United States	1999–2004	Population based	611	1,040	39	72
New England Lung Cancer Study (New England)	E. Duell	United States	2005–2008	Population based	277	251	61	46
Samuel Lunenfeld Research Institute (Toronto)	J. McLaughlin	Canada	1997–2002	Population and hospital based	445	962	62	71
Asian studies
National University of Singapore (Singapore)	A. Seow	Singapore	1996–1998	Hospital based	303	763	95	97
National Cancer Institute (Xuanwei1)	Q. Lan	China	1985–1990	Population based	498	498	100	97
National Cancer Institute (Xuanwei2)	Q. Lan	China	1995–1996	Population based	122	122	98	100

^aAs previously reported by Hashibe et al. (2006; California), Heck et al. (2009; New England), Hung et al. (2008; Toronto), Lan et al. (2000; Xuanwei2), Lan et al. (2008; Xuanwei1), Scélo et al. (2004; CEE), and Seow et al. (2000; Singapore).