Adjusted and unadjusted multiple logistic regression model for the association of self-reported nickel allergy and pierced ears with incident asthma for males and females; imputed data, excluding those with asthma at baseline
| Male (n=801) | Female (n=1124) | |||||
| Incident asthma# | cOR (95%CI) | aOR¶ (95%CI) | Incident asthma# | cOR (95%CI) | aOR¶ (95%CI) | |
| Nickel allergy | ||||||
| Never | 11 (1.5%) out of 727 | 1 | 1 | 15 (2.0%) out of 747 | 1 | 1 |
| Ever | 4 (7.1%) out of 56 | 4.67 (1.44–15.18) | 4.34 (1.22–15.41) | 7 (2.0%) out of 346 | 1.04 (0.41–2.6) | 0.93 (0.37–2.38) |
| Pierced ears | ||||||
| No | 9 (1.4%) out of 648 | 1 | 1 | 2 (1.9%) out of 103 | 1 | 1 |
| Yes | 6 (4.0%) out of 149 | 3.19 (1.11–9.11) | 3.19 (0.91–11.15) | 20 (2.0%) out of 1019 | 1.03 (0.24–4.47) | 0.96 (0.21–4.33) |
cOR: crude odds ratio; aOR: adjusted odds ratio. #: obtained from nonimputed data; ¶: adjusted for potential confounders (smoking status, parental socioeconomic status (SES), participant's SES, study centre and parental history of asthma).