Authors | Location | Date | Type |
Pollutants measured |
Number of cases |
Outcomesa | Conclusion |
---|---|---|---|---|---|---|---|
Ritz et al. [12] | California, USA | 1987 - 1993 |
Case/ control |
CO, O3 |
CP: 189 CL/P: 450 |
CP and CO (3rd month): OR = 0.71; 95% CI: 0.52 - 0.95 |
Inconclusive for orofacial clefts |
Chung et al. [17] | Hong Kong | 2002 - 2009 |
Case/ control |
NOx, O3, SO2 |
CP: 12 CL/P: 47 |
CL and NOx: -0.9 (P = 0.018) CL/P and NO: -0.699 (P = 0.031) |
Protective effect of NOx on CL and NO on CL/P |
Dolk et al. [18] | England | 1991 - 1999 | Cohort | NO2, PM10, SO2 |
CP: 302 CL/P: 586 |
None | No consistent conclusions |
Gilboa et al. [19] | Texas, USA | 1997 - 2000 |
Case/ control |
CO, NO2, O3, SO2, PM10 |
CP: 106 CL/P: 293 |
CL/P and PM10 (23.8 - <29 mcg/m3): OR = 1.45; 95% CI: 1.01 - 2.07 |
Limited risk of orofacial clefts from air pollutants |
Hansen et al. [20] | Australia | 1998 - 2004 |
Case/ control |
CO, NO2, O3, PM10, SO2 |
CP: 100 CL/P: 145 |
CL/P and SO2: OR = 1.27; 95% CI: 1.01 - 1.62 CP and PM10: OR = 0.69; 95% CI: 0.5 - 0.93 CL/P and CO: OR = 0.59; 95% CI: 0.42 - 0.8 |
SO2 increases risk of CL/P; PM10 protects against CP; CO protects against CL/P |
Hwang et al. [21] |
Taiwan | 2001 - 2003 |
Case/ control |
CO, NOx, O3, PM10, SO2 | CL/P: 653 |
CL/P and O3 (16.6 ppb - 45.1 ppb): 1st month: OR = 1.2; 95% CI: 1.02 - 1.39 2nd month: OR = 1.25; 95% CI: 1.03 - 1.52 Three-pollution model: 1st month: OR = 1.18 - 1.2; 95% CI: 1.01 - 1.41 2nd month: OR = 1.21 - 1.25; 95% CI: 1.03 - 1.56 |
Increased risk of CL/P with O3 exposure |
Marshall et al. [22] | New Jersey, USA | 1998 - 2003 |
Case/ control |
CO, NO2, O3, PM10, SO2 |
CP: 303 CL/P: 414 |
CL/P and SO2 (>0.007 ppm): OR = 1.6; 95% CI: 1.1 - 2.2 CP and CO (>1.02 ppm): OR = 0.5; 95% CI: 0.3 - 0.7 |
Increased risk of CL/P with SO2 exposure; Protective effect of CO on CP |
Rankin et al. [23] | England | 1985 - 1990 |
Case/ control |
PM4, SO2 | CL/P: 215 | None | Limited power of study with many confounders |
aOnly statistically significant outcomes are included. |