No of sports played† | GSTP1 genotype | Interaction p value§ | |||
No (with asthma/without asthma) | HR (95% CI) | No (with asthma/without asthma) | HR (95% CI) | ||
SNP3 (Ile105Val) | |||||
Ile/Ile | Ile/Val or Val/Val | ||||
None | 21/226 | 1 (Ref) | 36/365 | 0.90 (0.5 to 1.6) | 0.02 |
1–2 | 37/286 | 1.42 (0.8 to 2.5) | 33/444 | 0.73 (0.4 to 1.3) | |
>2 | 10/46 | 2.66 (1.2 to 5.9)¶ | 5/71 | 0.68 (0.2 to 1.9) | |
p Value‡ | 0.03 | 0.41 | |||
SNP1 (rs6591255 A>T) | |||||
AA | AT/TT | ||||
None | 20/254 | 1 (Ref) | 37/337 | 1.92 (1.1 to 3.5)¶ | 0.08 |
1–2 | 26/282 | 1.17 (0.6 to 2.1) | 44/448 | 1.87 (1.0 to 3.4) | |
>2 | 9/48 | 2.49 (1.1 to 5.7)¶ | 6/69 | 1.84 (0.7 to 4.8) | |
p Value‡ | 0.07 | 0.81 |
*All models are adjusted for ethnicity, community of residence, GSTM1 and SNP1/SNP3.
†Children were categorised by the number of team sports played.
‡A test for a trend was performed using the likelihood ratio test comparing full (dummy variables for 1, 2 and 2+ sports participation) to base models stratified by Ile1905Val status.
§Interaction p value was calculated from likelihood ratio test comparing full (main effect of sports, SNP and interaction term for sport category and SNP) to the base (main effect of sports and SNP only) models.
¶p value<0.05.
GST, glutathione-S-transferase; SNP, single nucleotide polymorphism.