Ambient air pollution exposure, residential mobility and term birth weight in Oslo, Norway☆,☆☆
Introduction
Birth outcome, and especially low birth weight, is considered as an important predictor of children’s health (McCormick, 1985; Wilcox, 2001), later life health such as coronary heart disease (Barker, 1995), and other health problems (Ashdown-Lambert, 2005). In recent years, several studies have examined the associations between birth outcomes and exposure to environmental factors such as tobacco smoking, ambient and indoor air pollution (Brauer et al., 2008; Nethery et al., 2008; Bell et al., 2007; Ritz and Yu, 1999; Maisonet et al., 2001; Dejmek et al., 1999; Baxter et al., 2007; Jedrychowski et al., 2006; Rauh et al., 2004). The findings on the association between air pollution exposure during pregnancy and pregnancy outcomes have been summarized in recent reviews (Ritz and Wilhelm, 2008; Lacasaña et al., 2005; Šrám et al., 2005; Maisonet et al., 2004; Glinianaia et al., 2004). The authors conclude that there is supportive evidence of associations between ambient air pollution and birth weight. However, the results are not conclusive, and the causal mechanisms are not yet clear.
Differences in study design and inclusion criteria, and different approaches in assessing exposure make it difficult to compare results between studies (Slama et al., 2008; Parker and Woodruff, 2008). A common approach in these types of epidemiological studies is to define exposure for the entire pregnancy based on the mothers registered address at the time of birth. Studies have shown that in some societies, up to 30% of women move during their pregnancy (Khoury et al., 1988; Fell et al., 2004; Shaw and Malcoe, 1992; Canfield et al., 2006). Using only the residential address registered on delivery could give raise to misclassified exposure estimates due to change of residency during pregnancy, since one can expect increased variability in exposure when using additional addresses for each pregnant woman (Ryan et al., 2008).
The purpose of this study was to use a population-based approach to examine associations between ambient environmental exposure, residential mobility and term birth weight. We hypothesized that reduced birth weight would be associated with higher exposure levels of ambient air pollution at both home and work address during pregnancy. We also wanted to test the hypothesis that differences in residential mobility during pregnancy could express additional unmeasured exposures and thereby affect any possible associations.
Section snippets
Design and study population
The target population consists of all singleton term live births with at least 37 weeks of completed gestation. The included births were registered between 1st January 1999 and 31st December 2002 in Oslo, Norway. We excluded births with maternal address outside Oslo during the pregnancy (n=715), plural deliveries (n=1046), term births with weight <1000 grams, or births with missing information on offspring’s gender or weight (n=119). Pregnancies with missing exposure on ambient air pollution
Results
Table 1 provides descriptive statistics of the study population. A total of 25,229 term live births were included in this study, with 1.2% being LBW and 9.6% being SGA. The mothers were predominantly western ethnic (75.7%) with a mean age of 30.7 years compared to 28.7 years for non-western ethnic mothers. A majority of the mothers were either married or living with a partner (83.3%). LBW was associated with female infants, shorter gestational age, first in birth order, maternal tobacco use,
Discussion
This study used a population-based sample with a detailed residential and pregnancy history for around 80% of all pregnancies in the study area. We used a dispersion model for air pollution exposure to assign residence-based concentrations in air pollution and did not rely on personal reporting of exposure to air pollution. We were able to receive registry-based information on moving date and included several microenvironments in the time weighting of exposure for each individual. By using a
Acknowledgements
The authors wish to acknowledge the services of The Medical Birth Registry of Norway. We also want to thank Statistics Norway for preparing the data.
References (51)
- et al.
Sources and concentrations of indoor nitrogen dioxide in Hamburg (west Germany) and Erfurt (west Germany)
Sci. Total Environ.
(2000) - et al.
Traffic-related differences in outdoor and indoor concentrations of particles and volatile organic compounds in Amsterdam
Atmos. Environ.
(2000) - et al.
Wintertime PM10 and Black Smoke concentrations across Europe: results from the PEACE study
Atmos. Environ.
(1997) - et al.
Spatial variation of PM2.5 chemical species and source-apportioned mass concentrations in New York City
Atmos. Environ.
(2004) - et al.
Variability of total exposure to PM2.5 related to indoor and outdoor pollution sources Krakow study in pregnant women
Sci. Total Environ.
(2006) - et al.
Residential mobility during pregnancy: implications for environmental teratogens
J. Clin. Epidemiol.
(1988) - et al.
PM10 particulate matter—the significance of ambient levels
Atmos. Environ.
(1997) - et al.
A review of the literature on the effects of ambient air pollution on fetal growth
Environ. Res.
(2004) - et al.
Developmental effects of exposure to environmental tobacco and material hardship among inner-city children
Neurotoxicol. Teratol.
(2004) - et al.
Origins of fetal growth restriction
Eur. J. Obstet. Gynecol. Reprod.
(2000)
Effects of ambient levels of air pollution generated by traffic on birth and placental weights in mice
Fertil. Steril.
A land-use regression model for estimating microenvironmental diesel exposure given multiple addresses from birth through childhood
Sci. Total Environ.
A UK-wide episode of elevated particle (PM10) concentration in March 1996
Atmos. Environ.
A review of intraurban variations in particulate air pollution: Implications for epidemiological research
Atmos. Environ.
Methodological issues in studies of air pollution and reproductive health
Environ. Res.
A review of low birth weight: predictors, precursors and morbidity outcomes
J. R. Soc. Health.
The fetal and infant origins of disease
Europ. J. Clin. Invest.
Predictors of concentrations of nitrogen dioxide, fine particulate matter, and particle constituents inside lower socioeconomic status urban homes
J. Expo. Sci. Environ. Epidemiol.
Ambient air pollution and low birth weight in Connecticut and Massachusetts
Environ. Health. Perspect.
A cohort study of traffic-related air pollution impacts on birth outcomes
Environ. Health Perspect.
Associations between short-term changes in nitrogen dioxide and mortality in Canadian cities
Arch. Environ. Health
Residential mobility patterns and exposure misclassification in epidemiologic studies of birth defects
J. Expo. Sci. Environ. Epidemiol.
Air pollution and birth weight in northern Nevada, 1991–1999
Inhal. Toxicol.
Fetal growth and maternal exposure to particulate matter during pregnancy
Environ. Health Perspect.
Residential mobility during pregnancy
Paediatr. Perinat. Epidemiol..
Cited by (78)
Ambient particulate matter (PM<inf>2.5</inf>) and adverse birth outcomes in Ho Chi Minh City, Vietnam
2023, Hygiene and Environmental Health AdvancesMaternal exposure to ambient PM<inf>2.5</inf> and term birth weight: A systematic review and meta-analysis of effect estimates
2022, Science of the Total EnvironmentEffect of outdoor air pollution and indoor environmental factors on small for gestational age
2021, Building and EnvironmentCitation Excerpt :A previous study conducted in the US demonstrated that increased maternal age significantly elevated the SGA risk, supporting our finding [85]. Some other cohort studies found that the foetus conceived in autumn who would be delivered during cold seasons (October and April) or born in autumn had a higher incidence rate of SGA in Norway [63], Australia [23], Netherland [64] and China [54] and higher rate of PSGA in China [9]. A recent study in the US reported a higher prevalence of TSGA in infants of male sex and born in extreme seasons (summer and winter) [21].
- ☆
Funding sources: This work was funded as a part of a doctoral thesis by the Norwegian Research Council. The names and personal ID numbers of participants were omitted from the data set to ensure confidentiality. The Norwegian Data Inspectorate approved the study, and the research was conducted in full accordance with the World Medical Association Declaration of Helsinki. Ulrike Gehring was supported by a research fellowship of the Netherlands Organization for Scientific Research (NWO).
- ☆☆
Approvals: The Norwegian Data Inspectorate reviewed and approved this study.