Distribution of joint ABO/secretor phenotypes in relation to age at onset of asthma in male children.
| Age at onset yrs | ABO/secretor phenotype | |||
| Nonsecretor/O | Nonsecretor/A, B or AB | Secretor/O | Secretor/A, B or AB | |
| ≤1 (a) | 8 (25.8) | 7 (22.6) | 3 (9.7) | 13 (41.9) |
| 1–5 (b) | 11 (20.8) | 1(1.9) | 19 (35.8) | 22 (41.5) |
| >5 (c) | 1 (11.1) | 2 (22.2) | 2 (22.2) | 4 (44.4) |
| Controls (d) | 22 (11.2) | 20 (10.2) | 69 (35.2) | 85 (43.4) |
Data are presented as number of subjects (per cent of subjects). A, B, AB and O refer to blood groups. Chi-squared test was used to compare groups as follows
A versus b versus c versus d: p=0.013
A versus b versus d: p=0.003
A versus b: p=0.005