The immune system and lungs of infants are immature. When these children are exposed to environmental tobacco smoke, they are at higher risk of developing allergies and asthma than infants who are not exposed. Exposed infants may develop allergic rhinitis, runny nose, nasal congestion and persistent sneezing. The immune system changes show up in babies as young as 2 months old.
University of Cincinnati Study
An environmental study conducted by University of Cincinnati epidemiologists linked environmental tobacco smoke to the development of allergic rhinitis in babies age 1 and younger. The Cincinnati Childhood Allergy and Air Pollution Study was funded by the National Institute of Environmental Health Sciences for five years to examine how environmental particulates, including indoor mold spores, influenced respiratory development and health. More than 40 percent of children are exposed to tobacco smoke in the home, according to Dr. Grace LeMasters, principal investigator and co-author of the Cincinnati study. Jocelyn Biagini, lead author of the study, said that, while the effects of mold were studied, it contributed more to the risk of ear infections than the development of allergies.
Factors and Findings
The Cincinnati study looked at the different risk factors for allergies, including exposure to pets, mold, environmental tobacco smoke, the day-care environment and siblings under 1 year of age. Infants who were exposed to 20 cigarettes a day or more were “three times more likely to develop allergic rhinitis by their first birthday than those who were not exposed,” according to Biagini. The same infants were exposed to a patch of mold approximately the size of a shoebox. These infants were five times more likely to come down with bacterial ear infections than infants living in homes free of mold.
Institute of Environmental Medicine
In a much larger study, researchers at the Institute of Environmental Medicine in Stockholm, Sweden, looked at the effects of secondhand smoke on infants. This study involved more than 4,000 families. The parents responded to questionnaires asking about their children's allergies and environmental factors the children were exposed to before and after birth, such as cigarette smoke, foods with high allergenic potential and pet dander. Researchers included outdoor air pollution, socioeconomic status – employment and educational histories of both parents -- and the allergy histories of each parent. Participating parents filled out these questionnaires when their children were 2 months, 12 months, 2 years and 4 years old. Blood samples were taken from over 2,500 children when they were 4 years old. Each child’s blood sample was studied for immunoglobulin, or IgE, antibodies.
Swedish Study Results
The Institute of Environmental Medicine developed the hypothesis that exposure to environmental tobacco smoke would increase the risk of respiratory allergies and disease in infants. The study’s objective was to determine whether prenatal or postnatal exposure to smoke would be related to IgE sensitization in the same children four years later.
Research results found no association between prenatal maternal smoking and IgE sensitization. However, the results were different when researchers looked at the “dose-response effect” of exposure to smoke related to parental cigarette smoking when the babies were only a few months old. IgE sensitization to smoke was already developing in infants 2 months old. These children were especially sensitive to cat dander and food allergens. The study reported that IgE sensitization appeared to be confined to the babies whose parents did not suffer from allergic diseases and who received smoke exposure in early infancy.
Effects of Cigarette Smoke
When infants are exposed to tobacco smoke at such an early age, they inhale harmful particulates, putting them at increased risk of developing asthma, according to LeMasters. The findings of the Cincinnati study show that babies and small children should not be exposed to secondhand smoke. Parents who smoke should quit. Smoking outside is not enough to reduce the risk of exposure because the smoke and its particulates settle on a smoker’s skin, hair and clothing.
References
- Health News University of Cincinnati; Tobacco Smoke Linked to Allergic Rhinitis in Infants; May 2006
- The Environmental Illness Resource; Babies Exposed to Second-Hand Smoke Have Increased Allergy Risk; Matthew Hogg; December 2007
- “Thorax;” Exposure to Environmental Tobacco Smoke and Sensitization in Children; Eva Lannero, et al.; December 2007
