Effects of Physical Activity on Breast Cancer Prevention: A Systematic Review
Bibliographic record
Abstract
BACKGROUND: Observational studies have reported an association between physical activity and breast cancer risk reduction. This study aims to evaluate the effect of physical activity on breast cancer prevention. METHODS: Articles were identified through literature available on Electronic databases (PubMed, Embase, Scielo, Cochrane, CINAHL, Cancerlit, and Google Scholar) and manual searches. Case control and cohort studies were assessed for methodological quality, using the Newcastle-Ottawa scale. RESULTS: Size, population, components, and characteristics of physical activity, and menopausal status were documented. Review Manager 5.1 performed analysis using the statistical method of Mantel-Haenszel. Fixed-effect analysis with dichotomous data, testing subgroups and calculating odds ratio with a confidence interval of 95% were used. MAIN RESULTS: 7 cohort studies and 14 case control studies were evaluated. Statistical evidence found that physical activity reduces the risk of breast cancer in case-control studies [OR = 0.84 (0.81-0.88)] (heterogeneity 72%) and cohort studies [OR = 0.61 (0.59-0.63)] (heterogeneity 100%). CONCLUSION: Physical activity seems to prevent breast cancer mainly in postmenopausal women.
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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 | 0.006 | 0.024 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.008 | 0.006 |
| Bibliometrics | 0.007 | 0.007 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 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".