Paternal Occupational Exposure to Endocrine-Disrupting Chemicals as a Risk Factor for Leukaemia in Children: A Case-Control Study from the North of England

Occupations with exposures to a variety of chemicals, including those thought to be potential endocrine disruptors, have been associated with an increased risk of leukaemia in offspring. We investigated whether an association exists between paternal occupations at birth involving such exposures and risk of leukaemia in offspring. Cases (n=958) were matched, on sex and year of birth, to controls from two independent sources, one other cancers, one cancer-free live births. Paternal occupations at birth were classified, using an occupational exposure matrix, as having “very unlikely,” “possible,” or “likely” exposure to six groups of potential endocrine-disrupting chemicals. There was a significantly increased risk of acute nonlymphocytic leukaemia (ANLL) for polychlorinated organic compounds (OR 1.95, 95% CI 1.08–3.54) only in comparison with cancer-free controls, and for phthalates (OR 1.61, 95% CI 1.00–2.61) only with registry controls. A number of other, including inverse, associations were seen, but limited to one control group only. No associations were seen with likely paternal exposure to heavy metals. The associations identified in this study require further investigation, with better exposure and potential confounding (for example maternal variables) information, to evaluate the likelihood of true associations to assess whether they are real or due to chance.

MODIFIED ANT COLONY OPTIMIZATION ALGORITHM AND ITS APPLICATION IN VARIABLE SELECTION OF QSAR OF POLYCHLORINATED ORGANIC COMPOUNDS

A modified ant colony optimization (ACO) algorithm was used for the selection of the variables that result in the best-fitted models for the bioconcentration factor (BCF) of polychlorinated organic compounds (PCOCs). The fitness function of the modified ACO is discussed in detail and a new expression for the fitness function is presented. The modified ACO is applied in quantitative structure–activity relationships of selected PCOCs for predicting BCFs and the best-fitting models by the ACO were obtained. The convergence velocity was acceptable.