Table 2
Difference in FEF25–75 related to ozone concentration on the day before spirometric testing according to antioxidant supplementation groups within GSTM1 genotypes among asthmatic children in Mexico City
| All asthmatics | Moderate and severe asthmatics | ||||||
|---|---|---|---|---|---|---|---|
| Group | Subgroup | n* | Coefficient (95% CI)†, ml/s 50 ppb O3 | Percentage (95% CI) change‡ FEF25–75/50 ppb O3 | n | Coefficient (95% CI), ml/s 50 ppb O3 | Percentage (95% CI) change FEF25–75/50 ppb O3 |
| *The number of subjects in each group is given. The number of observations is: GSTM1 null (placebo 654, supplement 732), GSTM1 positive (placebo 1065, supplement 1039). | |||||||
| †Results and 95% confidence intervals from generalised estimating equation models adjusted for age, height, use of bronchodilator, respiratory symptoms on the day of the spirometric test, minimum temperature, and time since the beginning of the study. Ozone level is 1 hour maximum. During the observation period the mean (SD) 1 hour maximum ozone level was 102 (47) ppb (range 12–309). The Mexican standard is 110 ppb. | |||||||
| ‡Percentage change from baseline FEF25−75 for the individual stratum. | |||||||
| §p⩽0.01. All p values were obtained by t test comparing coefficients between the two groups. | |||||||
| ¶0.01<p<0.05. | |||||||
| **0.05<p<0.10. | |||||||
| GSTM1 null | Placebo | 29 | −50.5 (−90.1 to−10.9)§ | −2.9 (−5.2 to −0.6)§ | 18 | −80.8 (−132.7 to −28.9)§ | −4.7 (−7.7 to −1.7)§ |
| Supplement | 33 | −3.0 (−40.7 to 34.7) | −0.2 (−2.3 to1.9) | 21 | −7.3 (−54.0 to 39.5) | −0.3 (−3.1 to 2.4) | |
| Supplement effect | 47.5 (−7.2 to 102.2)** | 2.7 (−0.2 to 5.8)** | 73.5 (3.8 to 143.2)¶ | 4.4 (0.3 to 8.4)¶ | |||
| GSTM1 positive | Placebo | 49 | −10.5 (−38.7 to 17.7) | −0.6 (−2.1 to 0.9) | 17 | −34.4 (−75.6 to 6.8) | −1.9 (−4.4 to 0.5) |
| Supplement | 47 | 5.1 (−29.8 to 40.1) | 0.3 (−1.6 to 2.2) | 26 | 2.0 (−43.8 to 47.8) | 0.1 (−2.4 to 2.6) | |
| Supplement effect | 15.6 (−29.2 to 60.4) | 0.9 (−1.6 to 3.3) | 36.4 (−29.0 to 101.9) | 2.0 (−1.7 to 5.7) | |||
