Table 1 Characteristics of infants for whom V′maxFRC was only available at 1 month of age compared with those for whom V′maxFRC was available at 1 month of age and at least a second occasion
V′maxFRC measured only at 1 month of age(n = 53)V′maxFRC measured at 1 month of age and on a second occasion(n = 190)
Male56% (29/53)56% (107/190)
Mother smoked during pregnancy27% (14/52)23% (43/190)
At least one parent with a history of asthma26% (12/47)33% (61/185)
Mean (SD) birth weight (kg)3.4 (0.5)3.4 (0.5)
Median (IQR) V′maxFRC at age 1 month (ml/s)88 (60, 119)94 (66, 130)
Mean (SD) length at 1 month assessment (cm)56 (5)55 (3)
Formula feeds introduced by 1 month of age32% (17/53)27% (34/124)

  • V′maxFRC, maximal flow at functional residual capacity; SD, standard deviation; IQR, interquartile range.

  • There were no significant differences between the groups.