Connection between unconjugated bilirubin level and spirometric parameters in adolescents with bronchial asthma
Authors:   Nizhny Novgorod City Children’s Clinical Hospital No. 1, Nizhny Novgorod, Russia, Boriskina O.S. , Eliseyeva T.I. ,   Privolzhskiy Research Medical University of the Ministry of Health of the Russian Federation, Nizhny Novgorod, Russia, Tush E.V. ,   Privolzhskiy Research Medical University of the Ministry of Health of the Russian Federation, Nizhny Novgorod, Russia, Khramova R.N. ,   Privolzhskiy Research Medical University of the Ministry of Health of the Russian Federation, Nizhny Novgorod, Russia, Ovsyannikov D.Yu. ,   Patrice Émery Lumumba People’s Friendship University of Russia, Moscow, Russia, Karpenko M.A. ,   Patrice Émery Lumumba People’s Friendship University of Russia, Moscow, Russia, Soodayeva S.K. ,   Research Institute for Pulmonology of the Russian Federal Biomedical Agency, Moscow, Russia, Kurbanova Z.M. ,   Privolzhskiy Research Medical University of the Ministry of Health of the Russian Federation, Nizhny Novgorod, Russia, Kubysheva N.I. ,   Kazan and the Volga Region Federal University, Kazan, Republic of Tatarstan, Russia, Khaletskaya O.V. ,   Privolzhskiy Research Medical University of the Ministry of Health of the Russian Federation, Nizhny Novgorod, Russia
Published: October 2024

Either a high-to-normal or slightly elevated total bilirubin level may have external respiration protective effect in patients with bronchial asthma (BA). However, Authors have searched but not found any studies related to the connection between the unconjugated bilirubin level and spirometric parameters in adolescents. The purpose of this research was to study the connection between unconjugated bilirubin level and spirometric parameters in adolescents with BA. Materials and methods used: a single-center observational cross-sectional pilot study of 74 adolescents aged 10 to 17 y/o with BA was conducted. All participants had undergone measurements of anthropometric and spirometric parameters, hematological parameters, both total and unconjugated bilirubin level. Results: elevated total bilirubin (17.1 mmol/l and higher) occurred in 40.5% (30) being the highest in homozygous carriers of UGT1A1 gene polymorphisms with an increased number of TA repeats, the differences were statistically insignificant. The unconjugated bilirubin level and such spirometric indicators as z-ratio of forced expiratory volume in 1 s (FEV1)/forced vital capacity of the lungs (FVC) and z-criterion of the mean forced expiratory flow during the 25-75% of FVC (MEF25-75) had statistically significant direct correlation (R=0,42, p<0,001, R=0,37, p=0,001, respectively). Patients with obstructive lung ventilation disorders at the time of examination (zFEV1/FVC less than -1.645) had lower levels of both total and unconjugated bilirubin, the differences were statistically significant (p=0.002 and p=0.004, respectively). Conclusion: statistically significant correlations between unconjugated bilirubin level and such spirometric parameters as zFEV1/FVC and zMEF25-75 as well as unconjugated bilirubin low level identification in patients with spirometric indicators of bronchial obstruction suggest a protective effect of unconjugated bilirubin on the development of bronchial obstruction in adolescents with BA.