Early Life Exposure to Phthalates, Biological Agents, and Traffic-related Air Pollution: Interactions and Impacts on Children’s Respiratory Health
Bibliographic record
Abstract
From conception onward, children develop within complex environments consisting of various indoor and outdoor exposures. These exposures shape a child's immune development and influence respiratory health during childhood and beyond. While numerous studies have investigated environmental risk factors for childhood respiratory health individually, few have explored the interactions among these factors. This dissertation examined the effect modification by indoor biological agents on the effects of early life exposure to phthalates and traffic-related air pollution (TRAP) on childhood asthma, using data from the CHILD Cohort Study. CHILD is a prospective birth cohort following children born from 2008 to 2012 in four sites in Canada: Edmonton, Toronto, Manitoba, and Vancouver.Using a case-cohort nested within CHILD, I investigated the modifying effects of pets on the relationship between di-(2-ethylhexyl) phthalate (DEHP) in house dust at 3 months and asthma diagnosis at age 5 and wheeze. Results indicated that dogs enhanced the respiratory effects of DEHP, whereas cats appeared protective. In a subset with quantified allergens and endotoxin levels, similar patterns of modification were found. These findings suggest potential interactions between phthalates and indoor biological agents at the population level. Using city-specific land-use regression-derived NO2 data (as a proxy for TRAP), I examined the associations between the first 3-month TRAP exposure and asthma diagnosis at age 5 and recurrent wheeze between 2-5 years of age. Pet ownership at 3 months and quantified pet allergens and endotoxin levels were then evaluated as potential effect modifiers. Interestingly, dogs and cats appeared to mitigate the TRAP effects on asthma development, while co-exposure to higher endotoxin levels increased TRAP-asthma associations. To inform strategies aimed at reducing children's exposure to DEHP, I assessed the associations between DEHP concentrations in house dust and building characteristics and consumer products. Vinyl flooring in kitchens and bathrooms, as well as plastic/vinyl furniture, were identified as possible DEHP sources in Canadian homes. Overall, these findings highlight the complex interplay between early-life environmental exposures and children’s respiratory health. Effective asthma prevention strategies should consider interactions between environmental risk factors, rather than focusing solely on individual pollutants.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".