Background: Maternal smoking has been consistently associated with increased risk of cleft lip with or without cleft palate (CL/P). Few studies have explored the possible effect of passive smoking. We examined the association between maternal passive smoking and the risk of CL/P among nonsmoking women in China.
Methods: Subjects included 88 infants with CL/P and 651 infants with no major external birth defects. Data were collected by trained health workers through face-to-face interviews.
Results: The odds ratio (OR) for CL/P associated with maternal passive smoking was 1.8 (95% confidence interval = 1.1–2.8). After adjustment for maternal occupation, periconceptional flu or fever, and infant sex, the risk was 2.0 (1.2–3.4). The adjusted ORs for exposure levels of 1–6 times per week and more than 6 times per week (at least 1 cigarette each time) were 1.6 (0.9–2.9) and 2.8 (1.5–5.2), respectively.
Conclusion: Maternal passive smoking during pregnancy was associated with an increased risk for CL/P in offspring.
From the aInstitute of Reproductive and Child Health, Peking University Health Science Center, Beijing, People's Republic of China; and bInstitute of Population Research/WHO Collaborating Center on Reproductive Health and Population Science, Peking University, Beijing, People's Republic of China.
Submitted 22 February 2009; accepted 1 July 2009; posted 15 January 2010.
Supported by the National Key Technologies Research and Development Program (Grant No. 2002BA709B11) and by the State Key Development Program for Basic Research (Grant No. 2007CB5119001), People's Republic of China.
Correspondence: Aiguo Ren, 38 Xueyuan Rd, Haidian District, Beijing 100191, People's Republic of China. E-mail: firstname.lastname@example.org. or Xiaoying Zheng, 5 Yiheyuan Rd, Haidian District, Beijing 100871, People's Republic of China. E-mail: email@example.com.