ORIGINAL ARTICLE

Impact of ambient air pollution on birth weight in Sydney, Australia

T Mannes¹, B Jalaludin², G Morgan³, D Lincoln⁴, V Sheppeard⁵ and S Corbett⁵

¹ NSW Public Health Officer Training Program, New South Wales Health Department, Australia
² Epidemiology Unit, South Western Sydney Area Health Service, Australia and School of Public Health and Community Medicine, University of New South Wales, Australia
³ Northern Rivers Department of Rural Health, Sydney University, Australia
⁴ NSW Biostatistical Officer Training Program, New South Wales Health Department, Australia
⁵ Environmental Health Branch, New South Wales Health Department, Australia

Correspondence to:
Correspondence to:
Ms T F Mannes
NSW Public Health Officer Training Program, New South Wales Health Department, LMB 961 North Sydney, Australia; paman{at}doh.health.nsw.gov.au

Background: Studies in Asia, Europe, and the Americas have provided evidence that ambient air pollution may have an adverse effect on birth weight, although results are not consistent.

Methods: Average exposure during pregnancy to five common air pollutants was estimated for births in metropolitan Sydney between 1998 and 2000. The effects of pollutant exposure in the first, second, and third trimesters of pregnancy on risk of "small for gestational age" (SGA), and of pollutant exposure during pregnancy on birth weight were examined.

Results: There were 138 056 singleton births in Sydney between 1998 and 2000; 9.7% of babies (13 402) were classified as SGA. Air pollution levels in Sydney were found to be quite low. In linear regression models carbon monoxide and nitrogen dioxide concentrations in the second and third trimesters had a statistically significant adverse effect on birth weight. For a 1 part per million increase in mean carbon monoxide levels a reduction of 7 (95% CI –5 to 19) to 29 (95% CI 7 to 51) grams in birth weight was estimated. For a 1 part per billion increase in mean nitrogen dioxide levels a reduction of 1 (95% CI 0 to 2) to 34 (95% CI 24 to 43) grams in birth weight was estimated. Particulate matter (diameter less than ten microns) in the second trimester had a small statistically significant adverse effect on birth weight. For a 1 microgram per cubic metre increase in mean particulate matter levels a reduction of 4 grams (95% CI 3 to 6) in birth weight was estimated.

Conclusion: These findings of an association between carbon monoxide, nitrogen dioxide, and particulate matter, and reduction in birth weight should be corroborated by further study.

Abbreviations: ABS, Australian Bureau of Statistics; APHEA, Short-term Effects of Air Pollution and Health: A European Approach; CI, confidence interval; EPA, Environment Protection Authority; IRSD, Index of Relative Socioeconomic Disadvantage; IUGR, intrauterine growth retardation; LBW, low birth weight; LMP, last menstrual period; MDC, midwives data collection; NSW, New South Wales; PM_2.5, particulate matter less than 2.5 microns diameter; PM₁₀, particulate matter less than 10 microns diameter; ppb, parts per billion (10^–9); ppm, parts per million (10^–6); SD, standard deviation; SE, standard error; SES, socioeconomic status; SGA, small for gestational age; OR, odds ratio; Temp, temperature; TSP, total suspended particulates

Keywords: small for gestational age; low birth weight; air pollution; air pollutants; environmental exposure; ozone; Australia; pregnancy outcomes; routinely collected data

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• Rich, D Q, Demissie, K, Lu, S-E, Kamat, L, Wartenberg, D, Rhoads, G G (2009). Ambient air pollutant concentrations during pregnancy and the risk of fetal growth restriction. J. Epidemiol. Community Health 63: 488-496 [Abstract] [Full Text]  
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