Air pollution and limb defects: a matched-pairs case-control study in Taiwan.
BACKGROUND
Air pollution influences the development of limb defects in animals. There is little epidemiologic evidence on the effect of prenatal air pollution exposure on the risk of limb defects.


OBJECTIVE
To assess the relations between exposure to ambient air pollutants and the risk of limb defects.


METHODS
We conducted a matched-pairs case-control study in Taiwan from 2001 through 2007. The case group consisted of 1687 limb defects and the control group was density-sampling matched one to ten based on the month and year of conception from 1510,064 live singleton newborns in 2001-2007. Adjusted conditional logistic regression models were used to estimate odds ratios per 10 ppb change for O3, NO2, 1 ppb change for SO2, 10 µg/m(3) change for PM10, and 100 ppb change for CO during the first trimester and first three gestational months.


RESULTS
Of the specific limb defects, reduction deformities of limbs (adjusted OR=1.024, 95% CI: 1.000, 1.048) was associated with a 1 ppb increase in SO2 during weeks of 9-12 of gestation as well as the first trimester. Reduction deformities of limbs was also associated with a 10 ppb increase in O3 during weeks of 1-4 of gestation (adjusted OR=1.391, 95% CI: 1.064, 1.818) among preterm births.


CONCLUSIONS
The present study provides evidence that exposure to outdoor air SO2 during the first trimester of pregnancy may increase the risk of limb defects. Exposure to O3 was associated with reduction deformities of limbs among preterm births. Similar levels of SO2 and O3 are encountered globally by large numbers of pregnant women.
Department of Public Health, College of Public Health, China Medical University, Taichung, Taiwan.
Yu-Ting
YT
Lin
Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan.
Yungling Leo
YL
Lee
Department of Public Health, College of Public Health, China Medical University, Taichung, Taiwan.
Chau-Ren
CR
Jung
Center for Environmental and Respiratory Health Research, Institute of Health Sciences, University of Oulu, Oulu, Finland.
Jouni J K
JJ
Jaakkola
Department of Occupational Safety and Health, College of Public Health, China Medical University, No. 91 Hsueh-Shih Rd, Taichung 40402, Taiwan. Electronic address: bfhwang@mail.cmu.edu.tw.
Bing-Fang
BF
Hwang
D000328:Adult; D000393:Air Pollutants / Q000009:adverse effects; D000397:Air Pollution / Q000009:adverse effects*; D016022:Case-Control Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D017880:Limb Deformities, Congenital / Q000209:etiology*; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects*; D010126:Ozone / Q000009:adverse effects*; D011247:Pregnancy; D012737:Sex Factors; D013458:Sulfur Dioxide / Q000009:adverse effects*; D055815:Young Adult
D000393:Air Pollutants; D013458:Sulfur Dioxide; D010126:Ozone
Air pollution; Children; Limb defects; Ozone; Sulfur dioxide