The Correlation between Maternal Exposure to Air Pollution and the Risk of Orofacial Clefts in Infants: a Systematic Review and Meta-Analysis.
OBJECTIVE
The authors performed a systematic review and meta-analysis to investigate the possible correlation between ambient air pollution and orofacial cleft anomalies in newborns.


METHODS
A literature search was performed using the PubMed and Google Scholar, using the keywords "air pollution", "cleft lip", "cleft palate", "carbon monoxide", "ozone", "sulfur dioxide", "nitrogen oxide", "nitrogen dioxide", and "aerodynamic diameter". Eight epidemiologic articles met the criteria of correlating either carbon monoxide (CO), ozone (O3), nitrogen oxides (NOx), airborne particulate matter of less than 10 µm in diameter (PM10), or sulfur dioxide (SO2) exposures with clefting of the palate alone, clefting of the lip alone, or clefting of the lip and palate. Odds ratios were extracted from the eight studies and tabulated in this meta-analysis. Quality analysis showed six high quality, one medium quality, and one low quality study.


RESULTS
Meta-analysis of the combined data confirmed the association of O3 exposure and risk of orofacial cleft anomalies (OR = 1.08; P = 0.02). NOx was consistently associated with decreased risk of cleft lip with or without palate and cleft palate.


CONCLUSIONS
Ozone showed the strongest correlation with cleft lip and cleft palate anomalies. However, the studies overall showed an inconsistent correlation between orofacial clefts and air pollutants.
Department of Vascular Surgery, Mount Sinai Cleft & Craniofacial Center, Icahn School of Medicine at Mount Sinai, New York USA.
Ajit
A
Rao
Department of Dentistry/Oral and Maxillofacial Surgery, Division of Plastic Surgery, Mount Sinai Cleft & Craniofacial Center, Icahn School of Medicine at Mount Sinai, New York USA.
Mairaj K
MK
Ahmed
Departments of Dentistry, Pediatrics, Surgery and Medical Education, Mount Sinai Cleft & Craniofacial Center, Icahn School of Medicine at Mount Sinai, New York USA.
Peter J
PJ
Taub
Private practice, Manalapan, New Jersey USA.
John S
JS
Mamoun
air pollution; cleft lip; cleft palate; ozone; systematic review