Trihalomethanes and Semen Quality in England and Wales
Bibliographic record
Abstract
ISEE-0663 Background and Objective: Disinfection by-products (DBPs) have been associated with adverse semen outcomes in laboratory animals. Of the DBPs, there is stronger evidence for the bromo- and chloro-acetic acids, while that for trihalomethanes (THMs) is heterogenous. However, two small epidemiological studies have found no association between DBPs and adverse semen outcomes in humans. In a large case-control study, we investigated the association between individual and total trihalomethanes (TTHM) and low motile sperm concentration (MSC) in six water regions in England and Wales between 1999 and 2002. Methods: Men were recruited from 13 fertility clinics in 9 centres across England and Wales between 1999 and 2002. THM concentrations in water zones were linked to data on semen quality for 647 cases and 936 controls, based on the men’s residence at the time the semen sample was obtained. Low MSC was calculated relative to time since last ejaculation. TTHM levels were categorized as low (< 35.71 μg/l), medium (35.71–49.86 μg/l), or high (49.87–95 μg/l). Results: Preliminary analyses using a crude measure of THM exposure (annual average THM) found no increased risk associated with TTHM. There were some excess risks found with the individual THMs. Conclusion: Our preliminary findings are inconclusive. Further analyses will use quarterly THM exposure data weighted to the time of sampling for more precise exposure, and adjust for potential confounders.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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".