Table 3.
Proportion (%) of subjects in different categories for early life risk factors and current smoking who had inactive, newly diagnosed and chronic asthma at age 22 years
| No Asthma |
Inactive |
Asthma at Age 22 Years Newly Diagnosed |
Chronic |
||||||
|---|---|---|---|---|---|---|---|---|---|
| Risk Factors* | Categories | Total n | (n) | %† (n+) | p‡ | %† (n+) | p‡ | %† (n+) | p‡ |
| Sex | Male | 404 | (271) | 14.5 (46) | 4.9 (14) | 21.2 (73) | |||
| Female | 445 | (323) | 8.0 (28) | 0.008 | 9.8 (35) | 0.023 | 15.4 (59) | 0.045 | |
| Parental asthma | Neither | 622 | (468) | 9.8 (51) | 6.0 (30) | 13.5 (73) | |||
| Either | 179 | (93) | 17.7 (20) | 0.018 | 15.5 (17) | 0.001 | 34.5 (49) | <0.0001 | |
| Parental smoking | No | 565 | (395) | 12.0 (54) | 7.3 (31) | 17.7 (85) | |||
| Yes | 273 | (194) | 8.5 (18) | 0.18 | 8.1 (17) | 0.7 | 18.5 (44) | 0.8 | |
| Eczema 2yr | No | 696 | (502) | 9.2 (51) | 7.9 (43) | 16.6 (100) | |||
| Yes | 79 | (40) | 28.6 (16) | <0.0001 | 9.1 (4) | 0.8 | 32.2 (19) | 0.004 | |
| Early Wheezing Phenotypes | Never | 354 | (297) | 6.0 (19) | ref | 4.2 (13) | ref | 7.8 (25) | ref |
| Transient | 135 | (99) | 10.0 (11) | 0.16 | 9.2 (10) | 0.055 | 13.2 (15) | 0.090 | |
| Late Onset | 107 | (47) | 27.7 (18) | <0.0001 | 14.6 (8) | 0.004 | 42.0 (34) | <0.0001 | |
| Persistent | 86 | (27) | 38.6 (17) | <0.0001 | 12.9 (4) | 0.044 | 58.5 (38) | <0.0001 | |
| Alternaria positive 6yr | No | 546 | (399) | 10.5 (47) | 7.2 (31) | 14.7 (69) | |||
| Yes | 113 | (51) | 22.7 (15) | 0.006 | 5.6 (3) | 0.7 | 46.3 (44) | <0.0001 | |
| CA-BHR 6yr | No | 330 | (262) | 8.7 (25) | 4.0 (11) | 10.9 (32) | |||
| Yes | 58 | (29) | 19.4 (7) | 0.048 | 19.4 (7) | 0.001 | 34.1 (15) | <0.0001 | |
| V'maxFRC Quartiles 6yr | High | 132 | (106) | 8.6 (10) | ref | 6.2 (7) | ref | 7.8 (9) | ref |
| Med-high | 132 | (91) | 12.5 (13) | 0.4 | 3.2 (3) | 0.3 | 21.6 (25) | 0.005 | |
| Med-low | 132 | (91) | 15.0 (16) | 0.15 | 6.2 (6) | 0.9 | 17.3 (19) | 0.036 | |
| Low | 132 | (75) | 14.8 (13) | 0.17 | 11.8 (10) | 0.17 | 31.2 (34) | <0.0001 | |
| Smoking 22yr | No | 625 | (439) | 12.4 (62) | 6.4 (30) | 17.6 (94) | |||
| Yes | 224 | (155) | 7.2 (12) | 0.068 | 10.9 (19) | 0.058 | 19.7 (38) | 0.5 | |
*
Eczema=physician diagnosis of eczema by age 2 years; CA-BHR=bronchial hyperresponsiveness to cold air challenge at age 6 years; Alternaria=allergy skin test positive to Alternaria alternata at age 6 years
†
Percentages for each asthma group were calculated with respect to the no asthma group after excluding the other two asthma groups.
‡
p-values for the association between each individual risk factor and the asthma groups were estimated using multinomial logistic regression with respect to the no asthma group.