Potential role of selection bias in the association between childhood leukemia and residential magnetic fields exposure: A population-based assessment
A partir des données de la cohorte "Northern California Childhood Leukemia Study", cette étude américaine ré-évalue, en prenant en compte des biais de sélection dans la population, l'association entre une exposition à des champs magnétiques en milieu résidentiel et le risque, précédemment observé dans des études cas-témoins, de leucémie pédiatrique
Résumé en anglais
Purpose : Data from the Northern California Childhood Leukemia Study (NCCLS) were used to assess whether selection bias may explain the association between residential magnetic fields (assessed by wire codes) and childhood leukemia as previously observed in case–control studies.
Methods : Wiring codes were calculated for participating cases, n = 310; and non-participating cases, n = 66; as well as for three control groups: first-choice participating, n = 174; first-choice non-participating, n = 252; and replacement (non-first choice participating controls), n = 220.
Results : Participating controls tended to be of higher socioeconomic status than non-participating controls, and lower socioeconomic status was related to higher wire-codes. The odds ratio (OR) for developing childhood leukemia associated with high wire-codes was 1.18 (95% CI: 0.85, 1.64) when all cases were compared to all first-choice controls (participating and non-participating). The OR for developing childhood leukemia in the high current category was 1.43 (95% CI: 0.91, 2.26) when participating cases were compared to first-choice participating controls, but no associations were observed when participating cases were compared to non-participating controls (OR = 1.06, 95% CI: 0.71, 1.57) or to replacement controls (OR = 1.06, 95% CI: 0.71, 1.60).
Conclusions : The observed risk estimates vary by type of control group, and no statistically significant association between wire codes and childhood leukemia is observed in the California population participating in the NCCLS.
