Washington: Children exposed to secondhand smoke in early childhood are more likely to become physically aggressive and antisocial as adults, according to a new study.These findings were regardless of whether their mothers smoked while they were pregnant or their parents had a history of anti-social behaviour."Moreover, exposure to this smoke at early childhood is particularly dangerous, as the child's brain is still developing," researcher Linda Pagani of the University of Montreal said."I looked at data that was collected about 2,055 kids from their birth until ten years of age, including parent reports about secondhand smoke exposure and from teachers and children themselves about classroom behaviour. Those having been exposed to secondhand smoke, even temporarily, were much more likely to report themselves as being more aggressive by time they finished fourth grade."Given that it would be unethical to expose children to secondhand smoke, Pagani relied on longitudinal data collected by Quebec health authorities from birth onward on an annual basis.Because parents went about raising their children while participating in the study, the data provided a natural experiment of variations in the child population of household smoke exposure throughout early childhood.Although no direct causal link can be determined, the statistical correlation suggests that secondhand smoke exposure does forecast deviant behavior in later childhood."This study suggests that the postnatal period is important for the prevention of impaired neurobehavioral development and makes the case for the promotion of an unpolluted domestic environment for children," Pagani added.The study was recently published in the Journal of Epidemiology and Community Health.