Residential mobility and childhood leukemia

A T Amoon; S Oksuzyan; C M Crespi; O A Arah; M Cockburn; X Vergara; L Kheifets

doi:10.1016/j.envres.2018.03.016

Residential mobility and childhood leukemia

Environ Res. 2018 Jul:164:459-466. doi: 10.1016/j.envres.2018.03.016. Epub 2018 Mar 23.

Authors

A T Amoon¹, S Oksuzyan², C M Crespi³, O A Arah⁴, M Cockburn⁵, X Vergara⁶, L Kheifets⁴

Affiliations

¹ Department of Epidemiology, University of California Los Angeles Fielding School of Public Health, 650 Charles E. Young Drive South, Los Angeles, CA 90095-1772, USA. Electronic address: aamoon@ucla.edu.
² Division of HIV and STD Programs, Los Angeles County Department of Public Health, 600 S Commonwealth Ave, Los Angeles, CA 90005, USA.
³ Department of Biostatistics, University of California Los Angeles Fielding School of Public Health, 650 Charles E. Young Drive South, Los Angeles, CA 90095-1772, USA.
⁴ Department of Epidemiology, University of California Los Angeles Fielding School of Public Health, 650 Charles E. Young Drive South, Los Angeles, CA 90095-1772, USA.
⁵ Department of Preventive Medicine, University of Southern California, Los Angeles, CA, 90089, USA.
⁶ Department of Epidemiology, University of California Los Angeles Fielding School of Public Health, 650 Charles E. Young Drive South, Los Angeles, CA 90095-1772, USA; Energy & Environment Sector, Electric Power Research Institute, 3420 Hillview Avenue, Palo Alto, CA 94304, USA.

Abstract

Aims: Studies of environmental exposures and childhood leukemia studies do not usually account for residential mobility. Yet, in addition to being a potential risk factor, mobility can induce selection bias, confounding, or measurement error in such studies. Using data collected for California Powerline Study (CAPS), we attempt to disentangle the effect of mobility.

Methods: We analyzed data from a population-based case-control study of childhood leukemia using cases who were born in California and diagnosed between 1988 and 2008 and birth certificate controls. We used stratified logistic regression, case-only analysis, and propensity-score adjustments to assess predictors of residential mobility between birth and diagnosis, and account for potential confounding due to residential mobility.

Results: Children who moved tended to be older, lived in housing other than single-family homes, had younger mothers and fewer siblings, and were of lower socioeconomic status. Odds ratios for leukemia among non-movers living <50 meters (m) from a 200+ kilovolt line (OR: 1.62; 95% CI: 0.72-3.65) and for calculated fields ≥ 0.4 microTesla (OR: 1.71; 95% CI: 0.65-4.52) were slightly higher than previously reported overall results. Adjustments for propensity scores based on all variables predictive of mobility, including dwelling type, increased odds ratios for leukemia to 2.61 (95% CI: 1.76-3.86) for living < 50 m from a 200 + kilovolt line and to 1.98 (1.11-3.52) for calculated fields. Individual or propensity-score adjustments for all variables, except dwelling type, did not materially change the estimates of power line exposures on childhood leukemia.

Conclusion: The residential mobility of childhood leukemia cases varied by several sociodemographic characteristics, but not by the distance to the nearest power line or calculated magnetic fields. Mobility appears to be an unlikely explanation for the associations observed between power lines exposure and childhood leukemia.

Keywords: Childhood leukemia; Electro-magnetic fields; Power lines; Residential mobility.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

California
Case-Control Studies
Child
Electromagnetic Fields / adverse effects*
Environmental Exposure* / adverse effects
Female
Humans
Leukemia*
Odds Ratio
Population Dynamics
Pregnancy

Grants and funding

P30 CA016042/CA/NCI NIH HHS/United States