TABLE 5.
ASSOCIATION (ADJUSTED LINEAR REGRESSION COEFICIENT) BETWEEN SWIMMING AT DIFFERENT AGE PERIODS AND LUNG FUNCTION AND AIRWAY RESPONSIVENESS AT 8 YEARS, EXPRESSED AS STANDARD DEVIATION SCORES ADJUSTED FOR HEIGHT, AGE, AND SEX
| Swimming | Mean Difference | 95% CI | N | ||
|---|---|---|---|---|---|
| FVC | |||||
| Age < 4 yr | Never | 0 (Reference) | 4,395 | ||
| Ever | −0.05 | −0.13 | 0.03 | ||
| Age 4–7 yr | Low | 0 (Reference) | 4,060 | ||
| Medium | −0.01 | −0.09 | 0.08 | ||
| High | 0.08 | 0.00 | 0.16 | ||
| Age 0–7 yr | Lowest | 0 (Reference) | 3,831 | ||
| Highest | 0.05 | −0.13 | 0.23 | ||
| FEV1 | |||||
| Age < 4 yr | Never | 0 (Reference) | 4,318 | ||
| Ever | −0.03 | −0.11 | 0.05 | ||
| Age 4–7 yr | Low | 0 (Reference) | 3,997 | ||
| Medium | 0.05 | −0.04 | 0.13 | ||
| High | 0.10 | 0.02 | 0.18 | ||
| Age 0–7 yr | Lowest | 0 (Reference) | 3,771 | ||
| Highest | 0.14 | −0.05 | 0.32 | ||
| FEV1:FVC | |||||
| Age < 4 yr | Never | 0 (Reference) | 4,383 | ||
| Ever | 0.00 | −0.00 | 0.01 | ||
| Age 4–7 yr | Low | 0 (Reference) | 4,050 | ||
| Medium | 0.01 | 0.00 | 0.01 | ||
| High | 0.00 | −0.00 | 0.01 | ||
| Age 0–7 yr | Lowest | 0 (Reference) | 3,821 | ||
| Highest | 0.01 | −0.00 | 0.02 | ||
| FEF25–75 | |||||
| Age < 4 yr | Never | 0 (Reference) | 4,419 | ||
| Ever | 0.04 | −0.04 | 0.12 | ||
| Age 4–7 yr | Low | 0 (Reference) | 4,081 | ||
| Medium | 0.10 | 0.02 | 0.19 | ||
| High | 0.09 | 0.01 | 0.17 | ||
| Age 0–7 yr | Lowest | 0 (Reference) | 3,851 | ||
| Highest | 0.20 | 0.02 | 0.39 | ||
| Bronchial hyperresponsiveness* | |||||
| Age < 4 yr | Never | 0 (Reference) | 2,848 | ||
| Ever | 0.08 | −0.08 | 0.25 | ||
| Age 4–7 yr | Low | 0 (Reference) | 2,677 | ||
| Medium | −0.04 | −0.22 | 0.14 | ||
| High | 0.05 | −0.12 | 0.21 | ||
| Age 0–7 yr | Lowest | 0 (Reference) | 2,584 | ||
| Highest | 0.03 | −0.33 | 0.40 | ||
Definition of abbreviations: CI = confidence interval; FEF25–75 = forced midexpiratory flow.
N = 5,738. Adjusting variable per model: FVC: body mass index, birth weight; FEV1: body mass index, birth weight, environmental tobacco smoke, atopy; Ratio FEV1:FVC: body mass index, sex, atopy; FEF25–75: older siblings, birth weight, atopy; Bronchial hyperresponsiveness: sex, maternal asthma, maternal hay fever, atopy.
*
Mean of least squares dose–response slope (% decline in FEV1 per μmol methacholine).
Bold indicates P < 0.05.