TABLE 4.
JOINT EFFECTS OF TRANSFORMING GROWTH FACTOR-β1 C-509T GENOTYPES AND rs4803457T/−509T DIPLOTYPES AND RESIDENTIAL DISTANCE FROM FREEWAY ON ASTHMA
| Residential Distance from Nearest Freeway (m) | Lifetime Asthma
|
Early Persistent Asthma
|
||||
|---|---|---|---|---|---|---|
| No Asthma (n) | n | OR (95% CI) | n | OR (95% CI) | ||
| rs1800469 (C-509T) | ||||||
| CC/CT | >1,500 | 949 | 153 | 1.0 (Ref.) | 55 | 1.0 (Ref.) |
| CC/CT | 1,001–1,500 | 246 | 45 | 1.01 (0.67–1.54) | 25 | 1.71 (0.95–3.10) |
| CC/CT | 500–1,000 | 300 | 52 | 0.91 (0.60–1.38) | 25 | 1.20 (0.66–2.18) |
| CC/CT | <500 | 239 | 36 | 0.93 (0.59–1.48) | 12 | 0.90 (0.43–1.89) |
| TT | >1,500 | 151 | 15 | 0.79 (0.43–1.44) | 7 | 1.08 (0.46–2.56) |
| TT | 1,001–1,500 | 38 | 6 | 0.78 (0.29–2.11) | 6 | 2.53 (0.86–7.39) |
| TT | 500–1,000 | 52 | 14 | 1.95 (0.97–3.92) | 6 | 2.10 (0.75–5.92) |
| TT | <500 | 30 | 9 | 3.10 (1.29–7.44) | 5 | 5.48 (1.72–17.42) |
| P* = 0.02 | P* = 0.18 | |||||
| No. of rs4803457T/-509T diplotypes | ||||||
| 0 or 1 | >1,500 | 1.0 (Ref.) | 1.0 (Ref.) | |||
| 0 or 1 | 1,001–1,500 | 1.01 (0.67–1.54) | 1.71 (0.95–3.10) | |||
| 0 or 1 | 500–1,000 | 0.90 (0.60–1.36) | 1.19 (0.66–2.16) | |||
| 0 or 1 | <500 | 0.93 (0.59–1.48) | 0.90 (0.43–1.89) | |||
| 2 | >1,500 | 0.80 (0.44–1.45) | 1.09 (0.46–2.57) | |||
| 2 | 1,001–1,500 | 0.78 (0.29–2.11) | 2.53 (0.86–7.39) | |||
| 2 | 500–1,000 | 2.08 (1.03–4.19) | 2.25 (0.79–6.37) | |||
| 2 | <500 | 3.11 (1.30–7.46) | 5.49 (1.73–17.48) | |||
| P* = 0.02 | P* = 0.18 | |||||
Definition of abbreviations: CI = confidence interval; OR = odds ratio.
ORs adjusted for age, sex, ethnicity, atopic status, parental history of asthma, annual family income, parental education, in utero exposure to maternal smoking, number of smokers at home, insurance status, and community of residence. Children living in Lake Arrowhead and Lompoc were excluded from the analysis. Models could not be fit for late-onset asthma phenotype.
P values for TGF-β1 C-509T by residential distance from nearest freeway were obtained from likelihood ratio test from nonstratified models with appropriate interaction terms and were based on 3 degrees of freedom.