Differences in exposure assignment between conception and delivery: the impact of maternal mobility.

In studies of reproductive outcomes, maternal residence at delivery is often the only information available to characterise environmental exposures during pregnancy. The goal of this investigation was to describe residential mobility during pregnancy and to assess the extent to which change of residence may result in exposure misclassification when exposure is based on the address at delivery. Maternal residential mobility was compared between neural tube defect cases and unaffected controls from Texas participants in the National Birth Defects Prevention Study (NBDPS). Maternal residential information was obtained from the NBDPS interview. Data from the U.S. EPA National Air Toxics Assessment [Assessment System for Population Exposure Nationwide (ASPEN)], modelled at the census tract level, were used to estimate benzene exposure based on address at conception and address at delivery. Quartiles of exposure were assigned based on these estimates and the quartile assignments based on address at conception and address at delivery were compared using traditional methods (kappa statistics) and a novel application of mixed-effects ordinal logistic regression. Overall, 30% of case mothers and 24% of control mothers moved during pregnancy. Differences in maternal residential mobility were not significant between cases and controls, other than case mothers who moved did so earlier during pregnancy than control mothers (P = 0.01). There was good agreement between quartiles of estimated benzene exposure at both addresses (kappa = 0.78, P < 0.0001). Based on the mixed-effects regression model, address at delivery was not significantly different from using address at conception when assigning quartile of benzene exposure based on estimates from ASPEN (odds ratio 1.03, 95% confidence interval 0.85, 1.25). Our results indicate that, in this Texas population, maternal residential movement is generally within short distances, is typically not different between cases and controls, and does not significantly influence benzene exposure assessment.

[1]  L D Edmonds,et al.  The National Birth Defects Prevention Study , 2001, Public health reports.

[2]  W. King,et al.  Residential mobility during pregnancy. , 2004, Paediatric and perinatal epidemiology.

[3]  Peggy Reynolds,et al.  Childhood cancer incidence rates and hazardous air pollutants in California: an exploratory analysis. , 2002, Environmental health perspectives.

[4]  K. Hendricks,et al.  Parental Occupation and Neural Tube Defect–Affected Pregnancies Among Mexican Americans , 2002, Journal of occupational and environmental medicine.

[5]  A. Scheuerle,et al.  Are birth defects among Hispanics related to maternal nativity or number of years lived in the United States? , 2009, Birth defects research. Clinical and molecular teratology.

[6]  T. Einarson,et al.  Paternal organic solvent exposure and adverse pregnancy outcomes: a meta-analysis. , 2005, American journal of industrial medicine.

[7]  A. Olshan,et al.  Comparison of assessment methods for pesticide exposure in a case-control interview study. , 2001, American journal of epidemiology.

[8]  M. F. Mohamed,et al.  Volatile organic compounds in some urban locations in United States. , 2002, Chemosphere.

[9]  J. Olsen,et al.  Paternal Laboratory Work and Congenital Malformations , 2004, Journal of occupational and environmental medicine.

[10]  G. Shaw,et al.  Socioeconomic status in relation to selected birth defects in a large multicentered US case-control study. , 2007, American journal of epidemiology.

[11]  T. Burke,et al.  Personal exposure meets risk assessment: a comparison of measured and modeled exposures and risks in an urban community. , 2003, Environmental health perspectives.

[12]  Halûk Özkaynak,et al.  Modeling population exposures to outdoor sources of hazardous air pollutants , 2008, Journal of Exposure Science and Environmental Epidemiology.

[13]  T J Woodruff,et al.  Estimating cancer risk from outdoor concentrations of hazardous air pollutants in 1990. , 2000, Environmental research.

[14]  G. Shaw,et al.  Exposure misclassification due to residential mobility during pregnancy in epidemiologic investigations of congenital malformations. , 1993, Archives of environmental health.

[15]  M. Canfield,et al.  Residential mobility patterns and exposure misclassification in epidemiologic studies of birth defects , 2006, Journal of Exposure Science and Environmental Epidemiology.

[16]  M. Khoury,et al.  Residential mobility during pregnancy: implications for environmental teratogenesis. , 1988, Journal of clinical epidemiology.

[17]  F. Zhan,et al.  Are Maternal Occupation and Residential Proximity to Industrial Sources of Pollution Related? , 2008, Journal of occupational and environmental medicine.

[18]  R. Grant,et al.  Spatial and temporal trend evaluation of ambient concentrations of 1,3-butadiene and chloroprene in Texas. , 2007, Chemico-biological interactions.

[19]  L. E. Mitchell.  Epidemiology of neural tube defects , 2005, American journal of medical genetics. Part C, Seminars in medical genetics.

[20]  E. Symanski,et al.  Childhood Lymphohematopoietic Cancer Incidence and Hazardous Air Pollutants in Southeast Texas, 1995–2004 , 2008, Environmental health perspectives.

[21]  Ching-Fan Sheu,et al.  Fitting mixed-effects models for repeated ordinal outcomes with the NLMIXED procedure , 2002, Behavior research methods, instruments, & computers : a journal of the Psychonomic Society, Inc.

[22]  S G Selevan,et al.  Identifying critical windows of exposure for children's health. , 2000, Environmental health perspectives.

[23]  Richard B. Hayes,et al.  An expanded cohort study of cancer among benzene-exposed workers in China. Benzene Study Group. , 1996 .

[24]  Daniel A Axelrad,et al.  National Estimates of Outdoor Air Toxics Concentrations. , 1999, Journal of the Air & Waste Management Association.

[25]  P. Moran,et al.  Prenatal screening and diagnosis of neural tube defects , 2009, Prenatal diagnosis.

[26]  M Dosemeci,et al.  An expanded cohort study of cancer among benzene-exposed workers in China. Benzene Study Group. , 1996, Environmental health perspectives.

[27]  G. Shaw,et al.  Residential mobility during pregnancy for mothers of infants with or without congenital cardiac anomalies: a reprint. , 1992, Archives of environmental health.

[28]  C. Roberts,et al.  Residential mobility in a cohort of primiparous women during pregnancy and post‐partum , 2008, Australian and New Zealand journal of public health.

[29]  G. Shaw,et al.  Markers of acculturation and risk of NTDs among Hispanic women in California. , 2008, Birth defects research. Part A, Clinical and molecular teratology.