Passive Tobacco Exposure in School Age Children with Recurrent Respiratory Illness using Salivary Cotinine Assay

Abstract

The micro (indoor) and macro (outdoor) environments play a significant role in recurrent respiratory illnesses
in school-age children. Passive tobacco exposure is a leading underestimated cause of respiratory disease
burden.
Aim: To assess passive tobacco exposure in school-age children with recurrent respiratory illness by
measuring salivary cotinine.
Method: It is a cross-sectional study that included 160 children between 5 and 15 years with recurrent upper
and lower respiratory illness. A validated questionnaire was administered for patterns of respiratory illness,
socioeconomic status, micro and macro environment exposures with emphasis on tobacco. Salivary cotinine
was measured by ELISA and value >10ng/ml was considered equivalent to passive tobacco exposure.
Descriptive statistics were applied to compare tobacco exposed and unexposed groups. Chi-square test and
binary logistic regression were used to calculate significance.
Results: History of exposure to ETS and/or tobacco dust within households was present in 30.6%. In 23.1%,
bidi rolling was a family occupation. Passive tobacco exposure as determined by cotinine assay was present
in 63.7%. Salivary cotinine levels ranged from none to 21.2ng/mL with a median of 12.04ng/mL. Among
children with elevated cotinine, the history of tobacco exposure was present only in 38.2%. Residing in joint
family was significant (p=0.009) for elevated cotinine levels. There was no identifiable single significant risk
factor including tobacco exposure for asthma.
Conclusion: Passive exposure to tobacco is an underestimated risk factor in childhood respiratory illness.