NO2 and coarctation of the aorta Study Gilboa et al. 2005 OR (95% CI) 1.05 (0.81–1.36) Strickland et al. 2009 1.05 (0.81–1.36) Dolk et al. 2009 1.14 (0.90–1.44) Dadvand et al. 2011b 1.74 (1.00–2.50) Combined effect (ﬁxed) 1.17 (1.00–1.36) PM10 and ASDs Study Gilboa et al. 2005 Strickland et al. 2009 1.08 (0.87–1.35) Dolk et al. 2009 1.16 (0.69–1.93) Dadvand et al. 2011b 1.90 (0.74–1.22) OR (95% CI) 1.33 (1.11–1.60) Combined effect (ﬁxed) 1.14 (1.01–1.28) SO2 and tetralogy of Fallot Study Gilboa et al. 2005 OR (95% CI) 1.09 (0.98–1.20) Strickland et al. 2009 0.96 (0.88–1.04) Dolk et al. 2009 1.03 (1.01–1.05) Dadvand et al. 2011b 1.00 (0.92–1.08) Combined effect (ﬁxed) 1.03 (1.01–1.05) n cases n cases 183 275 176 122 756 189 379 127 256 951 85 299 146 125 655 n cases NO2 and tetralogy of Fallot Study Gilboa et al. 2005 OR (95% CI) 1.25 (0.94–1.67) Strickland et al. 2009 0.90 (0.59–1.38) Dolk et al. 2009 1.15 (0.88–1.50) Dadvand et al. 2011b 1.74 (1.00–2.50) Combined effect (ﬁxed) 1.20 (1.02–1.42) SO2 and coarctation of the aorta Study Gilboa et al. 2005 OR (95% CI) 1.08 (0.99–1.18) Strickland et al. 2009 1.01 (0.93–1.94) Dolk et al. 2009 1.13 (0.91–1.41) Dadvand et al. 2011b 1.05 (0.97–1.14) Combined effect (ﬁxed) 1.07 (1.01–1.13) O3 and cleft lip Study Ritz et al. 2002 Gilboa et al. 2005 Hwang et al. 2008 Hansen et al. 2009 OR (95% CI) 1.13 (0.90–1.40) 1.09 (0.90–1.31) 1.22 (1.03–1.46) 0.67 (0.40–1.12) Marshall et al. 2010 0.96 (0.75–1.24) Combined effect (ﬁxed) 1.10 (0.99–1.21) be available from validation studies (Nethery et al. 2008), and efforts should be made to also incorporate these in evaluations of con- genital anomaly risk. Furthermore, air pol- lution studies of other birth outcomes have moved toward trying to estimate more spe- cifically the exact pollutants responsible (e.g., transition metals contained in PM, PAHs, aromatic hydrocarbons) (e.g., Aguilera et al. 2009; Perera et al. 2003; Slama et al. 2007), rather than focusing on the regulated pollut- ants, and this would be a valuable direction for future congenital anomaly studies. Nearly all the reviewed studies were based on registry information. In such studies, resi- dential addresses are available only at birth, not in the first trimester of pregnancy, the most relevant period for causation of congen- ital anomalies (Moore and Persaud 1998). Furthermore, residential addresses only account for exposures near the home, not in other situations thought to make an impor- tant contribution to personal exposure, such as work location, commuting, and indoor air pollution sources (Nethery et al. 2008; Setton et al. 2010). However, congenital anomaly research in this field cannot easily move away from routinely registered data. Large case–con- trol studies with good information on residen- tial history and time–activity patterns may be a useful step forward, if they can be combined with accurate exposure assessments. Pregnancy Air pollution and congenital anomalies cohort studies in Europe are currently pooling resources to study effects of air pollution and other birth outcomes using land-use regression exposure models [European Study of Cohorts for Air Pollution Effects (ESCAPE) Project 2009], but few such cohorts are large enough to conduct meaningful analyses of congen- ital anomalies or include thorough enough ascertainment of congenital anomalies among pregnancy terminations as well as live births. Information from such studies may, however, provide useful information about the effect of including information on residential mobility and time–activity patterns on risk estimates for other birth outcomes (e.g., Aguilera et al. 2009; Chen et al. 2010; Lupo et al. 2010). n cases n cases 134 299 146 125 704 109 275 176 122 682 n cases 450 305 653 145 397 1,950 603 1.0 1.5 OR per 10 ppb 2.0 2.5 1.0 1.5 OR per 10 ppb 2.0 2.5 0.8 1.0 1.2 1.4 OR per 10 µg/m3 1.8 1.0 1.2 1.4 1.6 1.8 OR per 1 ppb 0.9 1.0 1.1 OR per 1 ppb 1.2 0.4 0.6 0.8 1.0 OR per 10 ppb 1.4 Figure 1. Forest plots showing risk estimates for individual studies and the combined meta-analysis result. Marker sizes represent the relative weight the study contributed to the summary estimation. (A) NO2 and coarctation of the aorta. (B) NO2 and tetralogy of Fallot. (C) PM10 and ASDs. (D) SO2 and coarctation of the aorta. (E) SO2 and tetralogy of Fallot. (F) O3 and cleft lip with or without cleft palate. Environmental Health Perspectives • volume 119 | number 5 | May 2011