New York: Children whose parents smoke tend to miss more school than their classmates with non-smoking parents -- possibly because of a higher rate of respiratory infections, a new study suggests.
Researchers found that among nearly 3,100 families in a national survey, children who lived with smokers missed an extra day out of the school year, on average.
They also tended to have more ear infections and "chest colds" than their peers did, and that seemed to partly explain the link between household smoking and missed school days.
The findings, reported in the journal Pediatrics, do not prove that parents` smoking, itself, leads to more absenteeism.
But they offer parents yet more incentive to quit the habit, according to Dr. Douglas E. Levy and colleagues at Massachusetts General Hospital.
Health experts already recommend that kids be shielded from secondhand smoke, which can increase their risk of respiratory infections like bronchitis and pneumonia, severe asthma and sudden infant death syndrome.
The new study is the first national look at how secondhand smoke might affect kids` school absences, according to the researchers.
Using data from a 2005 government health survey, they found that 14 percent of households with 6- to 11-year-old children had at least one smoker. That translates to 2.6 million children nationwide.
On average, children who lived with one or two smokers missed one to one and a half extra school days per year, versus kids in smoke-free homes.
That difference is small. But Levy`s team estimates that if secondhand smoke is the cause, it would account for one quarter to one third of missed school days among kids who live with smokers.
The researchers found that parents in households with two smokers reported higher rates of chest colds and ear infections in their kids -- two illnesses related to secondhand smoke exposure.
And that partly accounted for the smoking-absenteeism link.
"The health impact of living with a smoker is probably more extensive than our study shows, since the survey only asked about three conditions associated with smoke exposure and we know there are several more," Levy said in a news release.
"And since the absentee levels we report are averages," he added, "there probably are kids who miss much more school because they live with smokers than our study found."
When children miss extra school days, the researchers say, it`s not only the child who may be affected. If a parent has to stay home from work, the family takes a financial hit.
The researchers estimate that the extra school absences linked to smoking cost parents $176 million in lost wages in 2005 -- assuming a working parent stayed home each time a child was sick.
"Since almost half of the smoking households in our study had low incomes," Levy noted, "that impact may be strongest on households least able to afford it."
"Overall," the researchers write, "these results illustrate the extent of tobacco`s impact on child and family well-being, highlighting academic disadvantage and financial burden in families in which parents smoke."