Lead and bisphenol A concentrations in the Canadian population.
Bibliographic record
Abstract
BACKGROUND: Lead is a known toxicant that occurs naturally in the environment. Bisphenol A (BPA) is an industrial chemical used primarily in polycarbonate plastic and epoxy resins. It has been 30 years since lead exposure was measured at a national level, and it is the first time for a national assessment of BPA exposure. DATA AND METHODS: Data are from the 2007-2009 Canadian Health Measure Survey. Lead in whole blood (PbB) and urinary BPA were measured in 5319 and 5476 respondents aged 6 to 79, respectively. Geometric means (GMs) are presented by age group and sex for PbB (pg/dL), volume-based BPA (microg/L), and creatinine-standardized BPA (microg/g creatinine). Adjusted least squares geometric means (LSGMs) for PbB and BPA are presented by selected covariates. RESULTS: PbB was detected in 100% of the population, with a GM concentration of 1.34 microg/dL. Adults aged 60 to 79 and males had significantly higher GM PbB concentrations. Lower household income, being born outside Canada, living in a dwelling at least 50 years old, current or former smoking, and drinking alcohol at least once a week were associated with higher PbB concentrations. Urinary BPA was detected in 91% of the population, with a GM concentration of 1.16 microg/L (1.40 microg/g creatinine). Children aged 6 to 11 had significantly higher GM creatinine-standardized BPA concentrations than did other age groups. INTERPRETATION: Although PbB concentrations have declined dramatically since the 1970s, socio-demographic characteristics, the age of dwellings, and certain lifestyle behaviours are associated with higher levels. Given the short half-life of orally ingested BPA and the high frequency of detection, the CHMS data suggest continual widespread exposure in the Canadian population.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.006 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".