Table 2 Lung function results in male (n = 42) and female (n = 34) infants before and after adjustment.
| Variable | Male | Female | Difference* | Adjusted difference† | Adjusted difference‡ | R2 (total)¶ (%) | R2 (sex)§ (%) |
|---|---|---|---|---|---|---|---|
| FRCpleth (ml) | 244.2 (50.8) | 213.6 (34.5) | 30.6 (9.8 to 51.5) | 32.4 (8.0 to 56.8) | 37.8 (13.7 to 61.9) | 19.3 | 10.7 |
| FRCpleth (ml/kg) | 29.0 (6.6) | 23.7 (4.6) | 5.3 (2.5 to 8.0) | 4.0 (0.9 to 7.2) | 3.6 (0.5 to 6.8) | 37.6 | 17.2 |
| Raw (kPa/litre/s) | 3.79 (1.58) | 2.81 (1.01) | 0.98 (0.31 to 1.64) | 0.50 (−0.25 to 1.24) | 0.36 (−0.40 to 1.12) | 23.4 | 11.1 |
| sGaw (1/kPa.s) | 1.28 (0.45) | 1.93 (0.61) | −0.65 (−0.90 to −0.40) | −0.52 (−0.81 to −0.23) | −0.51 (−0.80 to −0.21) | 34.9 | 27.9 |
| FRCHe (ml) | 212.4 (45.6) | 201.3 (35.0) | 11.1 (8.3 to 30.6) | 11.8 (−10.7 to 34.4) | 19.9 (−1.8 to 41.6) | 18.5 | 1.8 |
| FRCHe (ml/kg) | 25.2 (5.5) | 22.0 (5.1) | 3.2 (0.7 to 5.7) | 2.4 (−0.5 to 5.2) | 2.1 (−0.9 to 5.0) | 32.8 | 8.7 |
Values are mean (SD) or mean (95% confidence interval).
*Male − female results.
†Difference between male and female infants adjusted for birthweight standard deviation score, days ventilated, and oxygen dependence at discharge.
‡Difference between male and female infants adjusted for birthweight standard deviation score, days ventilated, oxygen dependence at discharge, and length and weight at time of measurement, except where lung function measure is already adjusted for weight.
¶R2 (total) is the proportion of variability explained by model 2.
§R2 (sex) is the proportion of variability explained by sex alone.