Table 4.
Modification of the association between a standard deviation increase in the 1-year moving average of PM2.5 exposure and heart rate-corrected QT durationa; Normative Aging Study, 2003–2011.
| Characteristics | N visits | Change in QTc in ms (95% CI) |
|---|---|---|
| Oxidative stress genetic score < median | 153 | 3.1 (−3.7, 9.8) |
| Oxidative stress genetic score > median | 287 | 8.5 (1.9, 15) |
| P for interaction | 0.25 | |
| Not obeseb | 392 | 6.1 (1.0, 11) |
| Obese | 136 | 7.1 (−4.0, 18) |
| P for interaction | 0.55 | |
| No diabetes | 426 | 6.2 (1.4, 11) |
| Diabetes | 102 | 6.0 (−7.5, 20) |
| P for interaction | 0.83 | |
| No current beta blocker usec | 294 | 6.5 (0.14, 13) |
| Current beta blocker use | 234 | 2.1 (−4.7, 9.0) |
| P for interaction | 0.34 |
Models are adjusted for age, race, BMI, cholesterol, smoking history, current use of anti-hypertensive medications, diabetic status, alcohol intake, season, mean arterial pressure, and moving averages of temperature corresponding to the PM2.5 exposure duration of interest (using linear and quadratic terms).
Models assessing interactions with obesity exclude BMI.
Models assessing interactions with beta blocker use adjust for individual anti-hypertensive medications (ACE inhibitors, calcium channel blockers, angiotensin receptor agonists, alpha blockers, and diuretics), rather than a combined anti-hypertensive medication use variable.