Table 2.
Childhood and Early Adult Life Exposures and Physiologic Characteristics of CRS Participants by Lung Function Trajectory Class
| N | Low Trajectory | Normal Trajectory | P Value | ||
|---|---|---|---|---|---|
| Exposure, % (n/N) | |||||
| Parental smoking* | 491 | 51.1 (24/47) | 55.9 (248/444) | 0.53 | |
| Early day care† | 578 | 7.6 (4/53) | 7.2 (38/525) | 0.93 | |
| Early life RSV-LRI‡ | 533 | 41.2 (21/51) | 21.4 (103/482) | 0.001 | |
| Active smoking§ | 596 | 35.7 (20/56) | 32.4 (175/540) | 0.62 | |
| Physiologic measure, mean (95% CI) | |||||
| V′maxFRC in infancy, ml/s | 107 | 65.6 (45.0–95.7) | 118.5 (108.0–129.9) | 0.003 | |
| V′maxFRC at 6 yr, ml/s | 444 | 872.6 (795.0–957.7) | 1,212.2 (1,180.1–1,245.1) | <0.001 | |
| Peak flow variability at 11 yr, amp%mean | 489 | 0.103 (0.086–0.124) | 0.074 (0.070–0.078) | 0.001 | |
| Maximally attained FEV1 | 599 | <0.001 | |||
| Absolute, L | 3.53 (3.34–3.72) | 3.86 (3.80–3.92) | |||
| Percent predicted, % | 85.6 (83.3–87.9) | 94.5 (93.7–95.4) | |||
| Maximally attained FVC | 599 | <0.001 | |||
| Absolute, L | 5.06 (4.78–5.34) | 4.75 (4.67–4.83) | |||
| Percent predicted, % | 105.4 (102.8–107.9) | 100.3 (99.1–100.9) |
Definition of abbreviations: CI = confidence interval; CRS = Tucson Children’s Respiratory Study; LRI = lower respiratory illness; RSV = respiratory syncytial virus; V′maxFRC = maximal expiratory flow at FRC.
*
Mother or father ever reported smoking between enrollment and age 10 years.
†
Entry into large day care in first 6 months of life.
‡
RSV-LRI during first 3 years.
§
Any smoking between ages 16 and 26 years.