Risks Factors for COPD Among Never Smokers in Ontario, Canada
Bibliographic record
Abstract
Abstract RATIONALE: Chronic obstructive pulmonary disease (COPD) is traditionally associated with a history of smoking; however, up to 30% of the global COPD burden occurs in never smokers. Given the increasing global burden of COPD, there is urgent interest in developing a broader understanding of “non-traditional” COPD risk factors, to inform development of novel therapeutics and preventative strategies. This study aimed to identify risk factors for never-smoking-related COPD in Ontario, Canada in a real-world population cohort. METHODS: We conducted a longitudinal, population-based cohort study using provincial health administrative databases linked to survey data in Ontario, Canada. We included all individuals above the age of 35 years residing in Ontario between 2000/2001 to 2018/2019 with survey-recorded smoking information. Individuals with COPD were identified using a validated case definition. Multivariable logistic regression models were constructed to evaluate associations for COPD stratified by smoking status. Analyses were performed using SAS (SAS Institute, Cary, North Carolina, USA). RESULTS: The total cohort comprised 151,290 individuals, with 48.4% characterized as never smokers. The prevalence of COPD among never smokers was 9.7%, constituting 25.1% of all identified COPD cases. Never smokers with COPD were diagnosed at an older age (median 72, IQR 61-81) compared to smokers with COPD (median 64, IQR 55-73) and were predominantly female (67.1%). History of asthma was found to have the highest association with risk of incident never-smoking COPD (aOR 3.95, 95% CI 3.69-4.23). Incident COPD in never smokers also had greater association with high comorbidity rate (aOR 2.73, 95% CI 1.96-3.79) and previous respiratory disease (aOR 2.3 95% CI 1.95-2.7). Environmental tobacco smoke was a significant risk factor for COPD, with greater association in smokers (aOR 1.86, 95% CI 1.77-1.95) versus never smokers (aOR 1.2, 95% CI 1.04-1.37). Increased BMI > 30 kg/m2 was found to be a risk factor for COPD only in never smokers (aOR 1.32, 95% CI 1.24-1.41). Of air pollution measures, only increasing annual average PM2.5 exposure was associated with incident COPD and was similar between never smokers and smokers (aOR 1.08, 95% CI 1.03-1.13 versus aOR 1.05, 95% CI 1.02-1.08, respectively). Female sex (aOR 0.86, 95% CI 0.81-0.91) and increasing educational attainment were found to be protective of incident never-smoking-related COPD. CONCLUSIONS: As smoking rates in high-income countries decline, the relative importance of never smoking COPD will increase. This uniquely large cohort highlights the substantial burden of and identifies independent risk factors for incident COPD in never smokers.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 source (direct Gemma or distilled Codex), 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".