Parents' Smoking Boosts Child's Allergy Risk

A smoker lights up a cigarette in Geneva, August 22, 2007. About 7.6 million people will die this year worldwide from various types of cancer, with lung cancer -- heavily driven by smoking -- killing 975,000 men and 376,000 women, the American Cancer Society said on Monday. REUTERS/Denis BalibouseTHURSDAY, Dec. 20 (HealthDay News) -- Exposure to secondhand smoke inearly infancy can boost a child's risk of developing allergies, Swedishresearchers say.
A team at the Karolinska Institute, Stockholm, analyzed questionnairesfilled out by the parents of more than 4,000 families.
The parents filled out the questionnaires when their children were agestwo months, 12 months, 2 years and 4 years. In addition, the researcherscollected blood samples from more than 2,500 children at the age of 4 tocheck for the presence of immunoglobulin E (IgE), which is released by theimmune system in response to allergens. High levels of IgE indicatesensitization to allergens.
About 8 percent of the mother smoked throughout their pregnancy, andabout 12 percent smoked during part of their pregnancy, but theresearchers found no evidence that smoking during pregnancy affected achild's risk of becoming sensitized to certain allergens.
About 20 percent of parents smoked after their baby was born, and about4 percent of the children were exposed to secondhand smoke from bothparents.
Overall, 25 percent of the children had high IgE levels by the timethey were 4 years old, with 15 percent allergic to inhaled allergens, 16percent allergic to food allergens, and 7 percent allergic to both typesof allergens.
Compared to children of nonsmokers, children exposed to secondhandsmoke during early infancy were almost twice as likely to be allergic toinhaled allergens, such as pet dander, and about 50 percent more likely tohave food allergies.
The study was published in the journal Thorax.