Aim: To determine if lung function of infants of birthweight <1501 g changed relative to expectations between 8 and 14 years of age, particularly for those of birthweight <1000 g.

Methods: The subjects were consecutive survivors born in the Royal Women's Hospital, Melbourne. There were 86 with birthweights <1000 g born from 1/1/77 to 3/31/82, and 124 with birthweights 1000-1500 g born from 10/1/80 to 3/31/82. Lung function was measured at both 8 and 14 years of age, corrected for prematurity, on 67 (78%) of those of birthweight < 1000 g, and 85 (69%) of those of birthweight 1000 - 1500 g. Data were expressed as% predicted (% pr) for gender, height and age, unless otherwise indicated. Results: Overall, lung function was mostly within the normal range at 8 and 14 years (Table). There were significant changes, mostly improvements, in lung function between 8 and 14 years relative to expected values (Table). The improvements in some lung function variables were significantly greater in those of birthweight < 1000 g compared with those of birthweight 1000 - 1500 g (Table). Conclusions: Lung function improves significantly relative to expected values in children of birthweight < 1501 g between 8 and 14 years. The improvements are even greater in those of birthweight < 1000 g compared with those of birthweight 1000-1500 g.

Table 1 Table. Lung function data - results are mean (SD), unless otherwise indicated. FEV1=forced expired vol. in 1 s; FVC= forced vital capacity; RV=residual volume; TLC=total lung capacity.
Full size table