Table 5 Joint associations of GSTP1 Ile105Val* genotype and participation in team sports on the risk of new onset asthma among CHS participants residing in high and low ozone communities
No of sports playedLow ozone communities (n = 6)†High ozone communities (n = 6)†
Ile/IleIle/Val or Val/ValIle/IleIle/Val or Val/Val
No‡HR (95% CI)NoHR (95% CI)NoHR (95% CI)NoHR (95% CI)
None10/931 (Ref)20/1810.86 (0.4 to 1.9)11/1331 (Ref)16/1840.98 (0.4 to 2.3)
1–221/1421.37 (0.6 to 3.0)19/2050.69 (0.3 to 1.6)16/1441.37 (0.6 to 3.1)14/2390.80 (0.3 to 1.9)
>23/281.06 (0.3 to 4.0)2/380.50 (0.1 to 2.4)7/186.15 (2.2 to 7.4)§3/331.06 (0.3 to 4.1)
  • *All models are adjusted for ethnicity, community of residence, GSTM1 and SNP1. The effect of SNP3 was treated as “additive”.

  • †High and low ozone communities were defined according to average 10:00 to 06:00 ozone levels. The ozone levels (10:00 to 06:00) ranged from 46.5 to 64.9 ppb in the “high” ozone communities (mean 38.4 ppb) and from 28.6 to 45.5 ppb in the “low” ozone communities (mean 55.2 ppb).

  • ‡Children with and without asthma.

  • §p value<0.05.

  • GST, glutathione-S-transferase; SNP, single nucleotide polymorphism.