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Determinants of bronchial responsiveness to methacholine at school age in twin pairs
Kari Nikolajev1, Matti Korppi, Kyllikki Remes
1Department of Pediatrics, Kuopio University Hospital and University of Kuopio, Kuopio, Finland. kari.nikolajev@kuh.fi
Insights
Intrauterine growth retardation (IUGR) did not increase bronchial hyperresponsiveness in children born from multiple pregnancies. Post-neonatal respiratory infections, however, were linked to increased bronchial hyperresponsiveness, as measured by the methacholine inhalation challenge test (MIC).
Area of Science:
- Pediatric Pulmonology
- Neonatalogy
- Allergy and Immunology
Background:
- Multiple pregnancies often result in preterm birth and intrauterine growth retardation (IUGR), potentially impacting long-term respiratory health.
- Bronchial hyperresponsiveness (BHR) is a key feature of asthma, but its development in children born from multiple pregnancies requires further investigation.
- The methacholine inhalation challenge test (MIC) is a standard method for assessing BHR.
Purpose of the Study:
- To investigate the association between IUGR and BHR in children born from multiple pregnancies.
- To explore the role of post-neonatal respiratory infections in the development of BHR in this population.
- To evaluate BHR using the MIC test in children aged 7-15 years.
Main Methods:
- A cohort of 67 children from multiple pregnancies underwent methacholine inhalation challenge testing (MIC) to assess bronchial responsiveness.
- Children were categorized based on birth status, including intrauterine growth retardation (IUGR) and appropriate for gestational age (AGA).
- Perinatal factors, neonatal history, and post-neonatal respiratory infections were recorded and analyzed in relation to MIC results.
Main Results:
- No significant difference in BHR (MIC responders vs. non-responders) was found between infants with IUGR and those with appropriate growth for gestational age (AGA).
- Post-neonatal respiratory infections were equally common in both IUGR and AGA children.
- However, a significant association was observed between the occurrence of post-neonatal respiratory infections and the presence of bronchial hyperresponsiveness.
Conclusions:
- Intrauterine growth retardation (IUGR) is not a risk factor for developing bronchial hyperresponsiveness in children born from multiple pregnancies.
- Post-neonatal respiratory infections play a significant role in the development of bronchial hyperresponsiveness, irrespective of birth growth status.
- The findings highlight the importance of managing respiratory infections in early life to potentially prevent BHR development.
Abstract:
The methacholine inhalation challenge test (MIC) was used to evaluate bronchial responsiveness in 67 children who were the products of multiple pregnancies when they were 7-15 years old. At birth, 30 (45%) infants had intrauterine growth retardation (IUGR; birth weight <2 SD below normal birth weight, or birth weight difference >1.3 SD between twin-pairs), and 59 (88%) were born before 37 weeks of gestation. None of the children had doctor-diagnosed asthma. The provocative dose of methacholine causing a 20% fall in Wright's peak expiratory flow (WPEF) (PD20) was below 1,000 microg in 10 (15%) children, and they were classified as MIC responders. There were no differences in perinatal or neonatal factors between MIC responders and nonresponders; in particular, MIC responses did not differ between IUGR infants, and children with appropriate growth for gestational age (AGA) at birth. There were seven discordant pairs in which one child was a MIC responder and the other was not; 5 responders were IUGR, and 2 were AGA children (ns). Respiratory tract infections after the neonatal period were equally common in IUGR and AGA children. However, these infections were associated with later bronchial hyperresponsiveness. Doctor-diagnosed respiratory infections, numbers of antibiotic courses, episodes of otitis media, and the need for adenoidectomy, tonsillectomy, and tympanostomy were more common in MIC responders than in nonresponders. We conclude that IUGR was not associated with subsequent bronchial hyperresponsiveness in twin pairs assessed by the MIC test. A significant relationship was seen between bronchial hyperresponsiveness and infections after the neonatal period.
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