Association between Bacillus Calmette-Guérin (BCG) vaccination and inflammatory bowel disease: A two-stage sampling design within the Quebec Birth Cohort on Immunity and Health (CO·MMUNITY)
Bibliographic record
Abstract
BACKGROUND: Bacillus Calmette-Guérin (BCG) vaccination, primarily administered to prevent tuberculosis, exhibits nonspecific immune effects and could play a role in inflammatory bowel disease prevention. We investigated the associations of BCG with Crohn's disease and ulcerative colitis, and assessed sex-differences. METHODS: This two-stage study included 365,206 Canadians from the Quebec Birth Cohort on Immunity and Health (1970-2014; stage 1). Vaccination status was registry-based and inflammatory bowel disease cases were identified from health services with validated algorithms. We documented additional factors among 2644 participants in a nested case-control study in 2021 (stage 2). A two-stage logistic regression analysis was applied to estimate the odds ratios (OR), corrected for sampling fractions and adjusted for confounding factors. We used interaction terms to assess sex-differences on the multiplicative scale. RESULTS: In the stage 1 sample, 2419 cases of Crohn's disease and 1079 of ulcerative colitis were included. Forty-six percent of non-cases received the BCG vaccine as compared to 47% for Crohn's disease and 49% for ulcerative colitis. Associations differed by sex. BCG vaccination was not associated with Crohn's disease among men (OR = 0.91; 95% CI: 0.79-1.04) but was related to an increased risk among women (OR = 1.13; 95% CI: 1.00-1.28, P interaction: 0.001). For ulcerative colitis, there was a tendency toward a slightly elevated risk among men (OR = 1.09; 95%CI: 0.90-1.32), whereas the risk was more substantial for women (OR = 1.17; 95% CI:0.99-1.39, P interaction: <0.001). CONCLUSION: BCG vaccination does not play a preventive role in inflammatory bowel disease. Our results point to distinct associations between men and women.
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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 | 0.004 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".