Domestic radon exposure and risk of childhood cancer: a prospective census-based cohort study.
BACKGROUND
In contrast with established evidence linking high doses of ionizing radiation with childhood cancer, research on low-dose ionizing radiation and childhood cancer has produced inconsistent results.


OBJECTIVE
We investigated the association between domestic radon exposure and childhood cancers, particularly leukemia and central nervous system (CNS) tumors.


METHODS
We conducted a nationwide census-based cohort study including all children < 16 years of age living in Switzerland on 5 December 2000, the date of the 2000 census. Follow-up lasted until the date of diagnosis, death, emigration, a child's 16th birthday, or 31 December 2008. Domestic radon levels were estimated for each individual home address using a model developed and validated based on approximately 45,000 measurements taken throughout Switzerland. Data were analyzed with Cox proportional hazard models adjusted for child age, child sex, birth order, parents' socioeconomic status, environmental gamma radiation, and period effects.


RESULTS
In total, 997 childhood cancer cases were included in the study. Compared with children exposed to a radon concentration below the median (< 77.7 Bq/m3), adjusted hazard ratios for children with exposure ≥ the 90th percentile (≥ 139.9 Bq/m3) were 0.93 (95% CI: 0.74, 1.16) for all cancers, 0.95 (95% CI: 0.63, 1.43) for all leukemias, 0.90 (95% CI: 0.56, 1.43) for acute lymphoblastic leukemia, and 1.05 (95% CI: 0.68, 1.61) for CNS tumors.


CONCLUSIONS
We did not find evidence that domestic radon exposure is associated with childhood cancer, despite relatively high radon levels in Switzerland.
Swiss Tropical and Public Health Institute, Basel, Switzerland.
Dimitri
D
Hauri
Ben
B
Spycher
Anke
A
Huss
Frank
F
Zimmermann
Michael
M
Grotzer
Nicolas
N
von der Weid
Damien
D
Weber
Adrian
A
Spoerri
Claudia E
CE
Kuehni
Martin
M
Röösli
D000293:Adolescent; D000396:Air Pollutants, Radioactive / Q000009:adverse effects*; D019352:Censuses; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D009369:Neoplasms / Q000453:epidemiology*; D011446:Prospective Studies; D011886:Radon / Q000009:adverse effects*; D012307:Risk Factors
D000396:Air Pollutants, Radioactive; D011886:Radon