Enhanced deposition of radon daughter nuclei in the vicinity of power frequency electromagnetic fields

The relation between exposure to electric and magnetic fields in the home, as assessed by measurements, wiring configuration, and self-reported appliance use, and risk of leukemia was investigated in a case-control study among children from birth to age 10 years in Los Angeles County, California. Cases were ascertained through a population-based tumor registry from 1980 to 1987. Controls were drawn from friends and by random digit dialing. Interviews were obtained from 232 cases and 232 controls. Available for analysis were measurements of the magnetic field in the child's bedroom over 24 hours or longer (164 cases and 144 controls), spot measurements of magnetic and electric fields (140 cases and 109 controls), and wiring configuration (219 cases and 207 controls). No clear associations between leukemia risk and measured magnetic or electric fields were seen. An association between the Denver Wertheimer-Leeper wiring configuration and childhood leukemia risk was observed (odds ratio for very high relative to very low current and underground configuration combined = 2.15, 95% confidence interval 1.08-4.28; p for trend = 0.008) and was not substantially altered by adjustment for potential confounding factors. Cases were more likely than controls to report use of several appliances that produce high electric and magnetic fields. Our results support an association between childhood leukemia risk and wiring configuration, but not direct measurements of electric and magnetic fields.

Data from a recently completed case-referent study of childhood cancer were used to explore a possible role of environmental exposures from traffic exhaust. The street addresses of 328 cancer patients and 262 population-based referents were used to assign traffic density (vehicles per day) as a marker of potential exposure to motor vehicle exhaust. An odds ratio of 1.7 [95% confidence interval (95% CI) 1.0-2.8] was found for the total number of childhood cancers and 2.1 (95% CI 1.1-4.0) for leukemias in a contrast of high and low traffic density addresses (greater than or equal to 500 versus less than 500 vehicles per day). Stronger associations were found with a traffic density cutoff score of greater than or equal to 10,000 vehicles per day, with imprecise odds ratios of 3.1 (95% CI 1.2-8.0) and 4.7 (95% CI 1.6-13.5) for the total number of cancers and leukemias, respectively. Adjustment for suspected risk factors for childhood cancer did not substantially change these results. Though the results are inconclusive, the identified association warrants further evaluation.