Table 1.
Demographic characteristics of the study population
| Participants with complete data (n = 7464) | Participants with data at 2–4 points (n = 8384) | |
|---|---|---|
| Eczema ever (reported in adolescence) | 2601/6309 (41.2) | 1435/3372 (42.6) |
| Perinatal characteristics | ||
| Male sex | 3780/7464 (50.6) | 4406/8374 (52.6) |
| Low birthweight (≤ 2500 g) | 302/7357 (4.1) | 449/7989 (5.6) |
| Parental characteristics | ||
| Maternal age at delivery, mean (SD) | 29.1 (4.6) | 27.6 (5.1) |
| Maternal asthma ever (recruitment) | 899/7412 (12.1) | 996/7786 (12.8) |
| Paternal asthma ever (recruitment) | 811/6256 (13.0) | 730/5855 (12.5) |
| Environmental characteristics | ||
| Breastfeeding ever | 5810/7331 (79.2) | 4986/6942 (71.8) |
| Maternal smoking (recruitment) | 1242/6516 (19.1) | 1933/6783 (28.5) |
| Paternal smoking (recruitment) | 2074/7366 (28.1) | 2801/7642 (36.6) |
| Presence of cat in home (recruitment) | 2219/7316 (30.3) | 2217/7742 (28.6) |
| Presence of dog in home (recruitment) | 1422/6712 (21.2) | 1783/7130 (25.0) |
| Outcomes in adolescence (age 14–18 years) | ||
| Asthma ever | 1648/6306 (26.1) | 913/3092 (29.5) |
| Current asthma | 696/5614 (12.4) | 360/2417 (14.9) |
| Current asthma medication | 637/5641 (11.3) | 294/2501 (11.8) |
| Cohort | ||
| ALSPAC | 5120/11 158 (45.9) | 6038/11 158 (54.1) |
| MAAS | 669/1135 (58.9) | 466/1135 (41.1) |
| SEATON | 471/1488 (31.7) | 1017/1488 (68.4) |
| IOW | 784/1455 (53.9) | 671/1455 (46.1) |
| Ashford | 420/612 (68.6) | 192/612 (31.4) |
Data are presented as n (%) unless otherwise stated. Valid percentages displayed using available data for each variable. ALSPAC, Avon Longitudinal Study of Parents and Children; MAAS, Manchester Asthma and Allergy Study; SEATON, Aberdeen; IOW, Isle of Wight.