Children who are exposed to secondhand smoke in early childhood are more likely to grow up to physically aggressive and antisocial, regardless of whether they were exposed during pregnancy or their parents have a history of being antisocial, according to Linda Pagani and Caroline Fitzpatrick of the University of Montreal and its affiliated CHU Sainte-Justine hospital. No study to date has controlled for these factors.
"Secondhand smoke is in fact more dangerous that inhaled smoke, and 40 per cent of children worldwide are exposed to it. Moreover, exposure to this smoke at early childhood is particularly dangerous, as the child's brain is still developing," Pagani 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."
The study was published in the Journal of Epidemiology and Community Health on May 21, 2013.
Given that it would be unethical to exposure 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 behaviour in later childhood.
