Prevalence of respiratory tract infections, allergies and assessment of humoral immunity within the Malopolska region's cohort of 11- year old children born with extremely low birth weight in comparison with to their term born peers.

Background: Children born with extremely low birth weight (ELBW) have more respiratory tract complications during childhood. Little is known about respiratory and allergy problems in ELBW children at the threshold of adolescence.

Materials and methods: A follow-up study was conducted at the age of 11 among ELBW children (n=65) and age-matched controls (n=36). The primary outcomes in the study were the occurrence of respiratory and allergy problems and the rate of hospitalization due to respiratory complications at the age of 11 years, assessed with a questionnaire. Secondary outcome variables were serum levels of immunoglobulin classes.

Results: ELBW children had more respiratory tract infections (31 vs.11%, p = 0.03), but less allergies (3 vs. 22%, p < 0.01) compared with controls and had lower level of serum tIgE (geometric mean: 46.5 vs. 89.3 kU/l, p = 0.02). The risk factors for the occurrence of respiratory tract disorders in the ELBW group were: low gestational age, need for surfactant therapy and length of ventilatory support in the neonatal period.

Conclusions: ELBW children have more frequent respiratory tract complications, but fewer allergies at the age of 11 years compared with children born at term. Lower respiratory tract problems decrease in ELBW children with age. Respiratory tract infections are not connected with deficiency in humoral immunity.