Urinary cotinine predicts pulmonary morbidity in children exposed to passive smoking

Abstract

Introduction Assessment of cotinine concentration in urine is considered a method of identifying exposure of children to second-hand smoking and its higher values reflect the deteriorated lung function. The aim in this study was to assess the relation between urine cotinine level and worse lung function in children exposed to parental smoking. Patients and methods A case–control study was designed including 65 children divided into two groups. The study group included 50 children who were exposed to parental smoking, and 15 other children with never smoked parents were considered in the control group. All recruited children were subjected to urine cotinine measurement as well as salivary secretory immunoglobulin A, amylase, and phosphate levels. Furthermore, all participants had lung function measurements. Results Both groups were matched for age and sex. Urine cotinine level was significantly increased in the study group vs controls. All measured spirometric indices [forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC, and forced expiratory flow (FEF)50–75] were significantly decreased in the study group compared with controls. Urinary cotinine showed a significantly inverse relationship with FEV1–FEV1/FVC and FEF50–75. Conclusion Children with passive smoking exposure tend to have a higher concentration of urine cotinine and decreased levels of salivary immunoglobulin A and amylase than children never exposed to second-hand smoking. Parental smoking inside households is considered a risk factor of worse lung function of their children.

Keywords

• children
• passive smoking
• spirometry
• urinery contonine