Birth size effect on pulmonary functions and atopic sensitization in preadolescence

Background: The purpose of the present paper was to examine whether low birth size is associated with reduced pulmonary function and increased atopic sensitization in preadolescence. Methods: A cohort of 25 small-for-gestational-age (SGA) infants and an age- and sex-matched comparison group of 29 appropriate-for-gestational-age (AGA) infants born in 1993/94 were studied in preadolescence. Forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and forced expiratory flow when 25-75% of FVC is expired (FEF25-75%) were measured using a spirometer. Atopic sensitization was assessed on serum total IgE levels and skin prick tests (SPT) to common allergens. Results: There were positive correlations among FEV1 (r = 0.30, P = 0.001), FVC (r = 0.20, P = 0.03), and FEF25-75% (r = 0.5, P = 0.001) and ponderal index (PI), although the FEV1/FVC ratio was not correlated with birth size. Mean value of serum total IgE was higher in SGA (106.0 +/- 73.4 IU/mL) than AGA children (71.4 +/- 67.1 IU/mL; P = 0.02). PI under 10th centile was associated with high IgE levels (P = 0.04, odds ratio, 3.2; 95%CI: 1.0-9.8). The overall prevalence of atopy was 14.8% and there was no significant difference between the groups (P > 0.05). Conclusion: Preadolescents who were born SGA with low birth size compared to controls had reduced pulmonary function. In preadolescence the prevalence of atopy is not higher in SGA than AGA children, although low PI at birth is associated with high IgE levels. Further follow up of this cohort is required to establish the pattern of pulmonary functions and atopic sensitizations in relation to birth size.