A Case-Crossover Analysis of Particulate Air Pollution and Cardiac Arrhythmia in Patients with Implantable Cardioverter Defibrillators
Bibliographic record
Abstract
We investigated the relationship between air pollution and incidence of cardiac arrhythmia in a study of patients with implantable cardioverter defibrillators (ICDs). Thirty-four patients (ages 15-85 yr, 80% male) with ICDs residing in the Vancouver, Canada, area were included in the analyses, representing all patients attending the 2 ICD clinics in the study region who had recorded at least 1 ICD discharge during the 14 February to 31 December 2000 study period. Air pollutant (PM(2.5), PM(10), SO(4)(2-), elemental carbon [EC], organic carbon [OC], O(3), SO(2), NO(2), and CO) concentrations on days for which ICD discharges were observed ("case days") were compared to concentrations on control days in case-crossover analyses. Control days were selected symmetrically, 7 days before and after each case day. ICD discharges occurring within 72 h of 1 another were grouped and considered as 1 discharge event. Temperature, relative humidity, barometric pressure, rainfall, and wind speed were included simultaneously as covariates. Sensitivity analyses examined the effect of grouping ICD discharges, of including meteorological variables, and of excluding discharges that were considered inappropriate by a cardiologist. As in previous studies, mean concentrations and interquartile ranges of air pollutants in Vancouver were low (e.g., PM(2.5) mean = 8.2 microg/m(3)). Although in general there were no statistically significant results, there were trends that might indicate associations between pollutants and ICD discharges. Odds ratios (OR) were consistently higher in summer than in winter (e.g., lag 0 per interquartile range increase in EC: 1.09 [0.86-1.37] vs. 0.61 [0.31-1.18]) and, in general, the highest ORs were observed for same-day effects. The one major exception was the observation of high ORs for ozone in winter (e.g., lag 1: 2.27 [0.67-7.66]). While an OR of 1.55 (0.51-4.70) was observed in summer at lag 0 for PM(10), no indications of positive associations were observed for PM(2.5) or SO(4)(2-). For indicators of local combustion-source pollution, EC, OC, CO, and SO(2), ORs were elevated at all lags (0-3 days) in summer. In summary, this study provides little evidence that specific components of PM affect risk of cardiac arrhythmias, although power limited the ability of the study to detect small effects.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".