Ethnic origin and lung function of infants born prematurely

Ethnic origin has an important influence on the lung function of adults and young children but its effect during infancy, particularly following premature delivery, is unclear.

The results from infants of pure Afro-Caribbean (subjects) and pure Caucasian (controls) descent, all of whom were born prematurely (median gestational age 28 weeks), were compared. Fifty subjects were each retrospectively matched with a control for gestational age, sex, and requirement for neonatal ventilation. Lung function measurements were performed at similar postnatal ages in each pair. The median postnatal ages of the two groups at the time of study was seven and eight months, respectively. Lung function was assessed by measurement of functional residual capacity (FRC) by a helium gas dilution technique and plethysmographic measurement of thoracic gas volume (TGV) and airways resistance (Raw), from which specific conductance (sGaw) was calculated.

No differences were found between the subjects and controls regarding FRC or TGV, but Raw was higher and sGaw lower in the subjects. The mean Raw of the subjects was 50.3 cm H2O/1/s and of the controls was 44.1 cm H2O/1/s (95% confidence intervals of the difference 1.5 to 10.9).

Prematurely born infants of Afro-Caribbean origin have more severe lung function abnormalities at approximately 7-8 months of age than those of Caucasian origin. This merits further investigation.