Allergy and Respiratory Infections in Infants ­ Effects of Tobacco Smoke, Mold, and Older Siblings

Jocelyn M. Biagini, MS and Grace LeMasters, Ph.D.
University of Cincinnati
R01ES11170 and T32ES10957

Exposure to environmental tobacco smoke increases an infant’s risk of developing allergic rhinitis by almost three­fold report NIEHS Grantee Grace LeMasters and trainee Jocelyn Biagini in the June issue of Pediatric Allergy and Immunology. The epidemiologic study was conducted with a group of 633 infants less than one­year of age and is the first to show the relationship between exposure to tobacco smoke and allergy in this age group. The researchers also found that exposure to mold in the home is associated with increased risk of upper respiratory infections but not allergy, which differs from previously reported research in older children and adults.

Other findings include a protective effect of having older siblings in the home. Infants with at least one older sibling were less likely to have allergic rhinitis, also known simply as hay fever, by their first birthdays. This finding supports the ”hygiene hypothesis,” a theory that exposure to infectious agents early in life may decrease the risk for allergic diseases such as asthma later in life. Presumably by having older siblings, these infants were exposed to a wider variety of viruses and bacteria causing their immune systems to develop in a way that decreases the risk of allergy.

About one-fifth of all American adults smoke cigarettes resulting in about 43 percent of children being exposed to home environmental tobacco smoke. Further research is necessary to confirm these results and to determine the components of cigarette smoke that cause the effects.

Citation: Biagini JM, Lemasters GK, Ryan PH, Levin L, Reponen T, Bernstein DI, Villareal M, Khurana Hershey GK, Burkle J, Lockey J. Environmental risk factors of rhinitis in early infancy. Pediatr Allergy Immunol. 2006 Jun;17(4):278-84.