PURPOSE OF THE STUDY.
The goal of this study was to establish atopic predisposition as a predictive factor to lower respiratory tract infection severity in infants with secondhand smoke (SHS) exposure.
Study patients were 451 mother–infant pairs enrolled in TCRI (Tennessee Children’s Respiratory Initiative). This longitudinal prospective study assessed familial atopic predisposition and severity of viral respiratory infections in infants with SHS exposure. Term infants with a birth weight ≥2275 g were enrolled from September to May of 2004 to 2008 when they presented with lower respiratory tract infection for an acute care visit to a single academic medical center.
A questionnaire was used for assessment of patient demographic characteristics, familial atopy predisposition, and environmental exposures. In this case, familial atopy predisposition was determined on the basis of 2 factors: (1) a mother with self-reported atopy or allergen sensitization; or (2) atopy in a first-degree relative of the infant. Medical records were reviewed. Hospital length of stay (LOS) and bronchiolitis severity scores (BSS) were used to determine severity of lower respiratory tract infection. Multivariable regression models were then used to investigate the relationship of SHS exposure, bronchiolitis severity, and family atopy.
Of 451 infants with lower respiratory tract infection, more than one-half had SHS exposure, more than one-third had mothers with atopic disease, and more than two-thirds had familial atopy. Univariate analysis showed that SHS resulted in higher BSS. However, when considering maternal atopic disease and allergic sensitization as variables, this study did not find a statistically significant difference in BSS or LOS with SHS exposure. Furthermore, utilizing familial atopy as a predictor of BSS in the SHS exposure groups showed no statistically significant difference versus those with no familial atopy. However, SHS exposure did increase the LOS of those infants with familial atopy. This finding is in contrast to patients with no familial atopy, in whom SHS did not affect LOS.
SHS was linked to longer LOS, but not BSS, in infants with familial atopy.
As physicians, we are often faced with the daunting task of smoke-cessation counseling, particularly for the benefit of children exposed to SHS. Studies such as these are often referred to by physicians in daily practice when counseling families regarding the need for parental smoking cessation. Unfortunately, this study is limited by parental reports of SHS that are likely to be underreported. Because this study describes increased LOS for infants with SHS and lower respiratory tract infection in those with familial atopy, it lays the groundwork for further studies that may explore the consequences of these findings on the long-term pulmonary health of children.
- Copyright © 2014 by the American Academy of Pediatrics