Table 3.
Percent change in liver enzyme concentrations with interquartile range increases in PM2.5, NO2, and O3 concentrations in multiple-pollutant models1
| IQR | AST |
ALT |
γ-GTP |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Estimate | 95% CI | p-value | Estimate | 95% CI | p-value | Estimate | 95% CI | p-value | ||
| PM2.5 | 13.2 µg/m3 | 2.1 | -0.1, 4.5 | 0.07 | 1.2 | -2.6, 5.0 | 0.55 | 4.3 | 0.5, 8.3 | 0.03 |
| NO2 | 14.4 ppb | 2.5 | -0.1, 5.3 | 0.06 | 3.1 | -1.0, 7.3 | 0.14 | -2.7 | -6.6, 1.4 | 0.20 |
| O3 | 38.5 ppb | 0.5 | -2.8, 3.9 | 0.77 | 2.9 | -0.8, 6.7 | 0.12 | 2.5 | -2.9, 8.2 | 0.37 |
IQR, interquartile range; AST, aspartate aminotransferase; ALT, alanine aminotransferase; γ-GTP, γ-glutamyltranspeptidase; CI, confidence interval; PM2.5, particulate matter ≤2.5 μm; NO2, nitrogen dioxide; O3, ozone; ppb, parts per billion.
Models for AST were constructed using the values for NO2 and O3 on lag day 2 and PM2.5 on lag day 3. Models for ALT were constructed using the values for NO2 and PM2.5 on lag day 2 and O3 on lag day 5. Models for γ-GTP were constructed using the values for NO2 on day 1, PM2.5 on day 3, and O3 on day 4. All models were adjusted for age, sex, smoking status, mean temperature, dew point, season, body mass index, alcohol consumption, and amount of exercise.