Smoking cigarette 370.
(photo credit: Daniel Munoz/Reuters)
Children that are exposed to secondhand smoke in early childhood are more likely
to grow up to be physically aggressive and antisocial – regardless if they were
exposed during pregnancy or their parents have a history of being antisocial –
researchers at the University of Montreal published in the Journal of
Epidemiology and Community Health.
Researchers Dr. Linda Pagani and
Caroline Fitzpatrick said that no study to date had controlled for these
“Secondhand smoke is in fact more dangerous than inhaled smoke
and 40 percent of children worldwide are exposed to it,” Pagani
Sidestream smoke, which emanates from a burning cigarette and
comprises 85 percent of secondhand smoke, contains a higher concentration of
many dispersed respirable pollutants than the inhaled-and-then-exhaled
“Exposure to this smoke at early childhood is
particularly dangerous, as the child’s brain is still developing,” Pagani
“I looked at data that was collected about 2,055 kids from their
birth until 10 years of age, including parent reports about secondhand smoke
exposure and from teachers and children themselves about classroom behavior.
Those having been exposed to secondhand smoke, even temporarily, were much more
likely to report themselves as being more aggressive by time they finished
Asked to comment, Prof. Alan Apter – head of
psychological medicine at Schneider Children’s Medical Center in Petah Tikva –
said that “I think that this is yet another indication of the hazards of smoke
exposure on the developing brain and thus adds to a mass of compelling evidence
that smoking and secondhand exposure should be as limited as
Apter continued that identifying children in this category can
also shed light on additional detrimental environmental factors that would
affect their psychological well-being.
“It is possible that exposure to
secondhand smoke is a marker for being disadvantaged and goes in hand with other
deleterious effects of adversity such as stress, poor general health and more
psychopathology in the parents.”
Since 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. Parents went
about raising their children while participating in the study and 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
proven, the statistical correlation suggests that secondhand smoke exposure does
forecast deviant behavior in later childhood, the authors wrote.
detailed information collated for the Quebec Longitudinal Study of Child
Development enabled Pagani to do something no other researcher had done to date
– distinguish the unique contribution of secondhand smoke exposure on children’s
later deviant behavior.
“Previous studies looking at groups of children
have generally asked mothers whether they smoked or not, and how much at each
follow-up, rather than asking whether someone smoked in the home where young
children live and play,” she said.
Pagani said that past studies rarely
took into account antisocial behavior in the parents, prolonged exposure to
secondhand smoke and that disadvantaged families are less likely to participate
in long term studies.
“We know that the starvation of oxygen caused by
smoke exposure in the developing central nervous system can cause low birth
weight and slowed fetal brain growth,” Pagani said. “Environmental sources of
tobacco smoke represent the most passive and preventable cause of disease and
This study suggests that the postnatal period is important
for the prevention of impaired neuro-behavioral development and makes the case
for the promotion of an unpolluted domestic environment for
Pagani said this is yet another indication of the hazards of
smoke exposure on the developing brain and thus adds to a mass of compelling
evidence that smoking and secondhand exposure should be as limited as possible.