Table II.
Characteristics of participants with at least 2 observations of wheeze (study population, n = 12,303) by sex
| Participants with 2-14 observations of wheezing (n = 12,303) |
|||||
|---|---|---|---|---|---|
| Male subjects (n1 = 6,330) |
Female subjects (n2 = 5,973) |
P value (χ2 test) | |||
| No./total | Percent | No./total | Percent | ||
| Potential confounders | |||||
| Lower maternal education∗ | 3,715/5,848 | 63.5 | 3,446/5,487 | 62.8 | .43 |
| Having ≥1 sibling (parity) | 3,202/5,777 | 55.4 | 2,946/5,413 | 54.4 | .29 |
| Maternal history of asthma or allergy | 2,652/5,721 | 46.4 | 2,487/5,411 | 46.0 | .68 |
| Maternal smoking during pregnancy | 1,570/5,774 | 27.2 | 1,364/5,449 | 25.0 | .009 |
| Maternal anxiety during pregnancy† | 1,193/5,434 | 22.0 | 1,117/5,106 | 21.9 | .92 |
| Low birth weight (<2.5 kg) | 293/5,951 | 4.9 | 282/5,580 | 5.1 | .75 |
| Preterm delivery (<37 wk) | 391/6,023 | 6.5 | 291/5,651 | 5.1 | .002 |
| Maternal smoking during first year | 1,334/5,557 | 24.0 | 1,195/5,255 | 22.7 | .12 |
| Day care attendance during first year | 333/5,493 | 6.1 | 308/5,136 | 6.0 | .89 |
| Variables used in latent class model | |||||
| Reported wheezing at: | |||||
| 6 mo | 1,683/5,673 | 29.7 | 1,191/5,331 | 22.3 | <.001 |
| 18 mo | 1,730/5,622 | 30.8 | 1,255/5,239 | 24.0 | <.001 |
| 30 mo | 1,312/5,144 | 25.5 | 932/4,801 | 19.4 | <.001 |
| 42 mo (3½ y) | 1,000/5,159 | 19.4 | 756/4,814 | 15.7 | <.001 |
| 54 mo | 1,035/4,861 | 21.3 | 739/4,530 | 16.3 | <.001 |
| 69 mo | 767/4,434 | 17.3 | 561/4,162 | 13.5 | <.001 |
| 81 mo | 646/4,321 | 15.0 | 481/4,074 | 11.8 | <.001 |
| 91 mo | 526/4,218 | 12.5 | 352/3,984 | 8.8 | <.001 |
| 103 mo (8½ y) | 626/4,160 | 15.0 | 424/4,000 | 10.6 | <.001 |
| 128 mo | 567/3,848 | 14.7 | 368/3,797 | 9.7 | <.001 |
| 140 mo | 508/3,692 | 13.8 | 361/3,707 | 9.7 | <.001 |
| 157 mo | 431/3,490 | 12.3 | 309/3,508 | 8.8 | <.001 |
| 166 mo | 427/3,475 | 12.3 | 336/3,455 | 9.7 | <.001 |
| 198 mo (16½ y) | 286/2,739 | 10.4 | 306/2,896 | 10.6 | .88 |
| Atopy at 7½ y (skin prick test) | 825/3,364 | 24.5 | 578/3,327 | 17.4 | <.001 |
∗
Educated to the General Certificate of Education level (school-leaving certificate) or lower.
†
Anxious mothers were defined as being in the fourth quantile of the Crown-Crisp Experiential Index.