Abstract

The aim of this study was to explore the unapparent relationships that several factors related to environmental exposures and individual characteristics existing in our environment seem to be involved with childhood leukaemia. From a database of clinical and epidemiological data obtained from hospital-based multicenter case-control study on risk factors for childhood leukaemia, exploratory multivariate analysis was performed the principal component and factor analysis. Further, an unconditional logistic regression was carried out aiming to ascertain the magnitude of association between the selected factors, and their composing variables, with childhood leukaemia. The model displaying the highest power explained 52% of the total variance, including three factors, each one of the showing factors loadings higher than 0.6: “conditions related to chemical exposure during pregnancy”, which explained 20% of the variance; “lifestyle exposures”, such as smoking and hair dyes and hair cosmetics use during pregnancy, explaining 17% of the total variance; and “consumption of health services during pregnancy”, such as x-rays and delivery type (cesarean or vaginal delivery), explaining 15% of the total variance. Logistic modelling revealed statistically significant association between childhood leukaemia and chemical exposure during pregnancy (OR=1.36; 95% CI 1.16 to 1.59), and also with consumption of health services during pregnancy (OR=1.27; 95% CI 1.08 to 1.49). The observed results are suggestive of the contribution of environmental exposures to childhood leukaemia development, not just individually, which has been supported by the literature according to carcinogenesis in general, and to leukaemogenesis in particular, as resulting from several mutations triggered by joint environmental exposures.