Abstract B02: Recreational physical activity, sedentary time and the incidence of colorectal polyps in a screening population for colon cancer
Bibliographic record
Abstract
Abstract Background: Despite the consistent association between regular recreational moderate to vigorous physical activity (rMVPA) and reduced risk of colorectal cancer (CRC), few studies have examined the effect of physical activity on carcinogenic development by examining colorectal adenomas (polyps). Furthermore, even fewer studies have examined the impact of sedentary behavior/time (ST) on the development of polyps. In this study we examined the associations between rMVPA and ST and the presence, number and type of colorectal polyps in a population undergoing screening for colorectal cancer in Calgary, Alberta, Canada. Methods: A cross-sectional study of 2,499 individuals undergoing colonoscopy at the Forzani & MacPhail Colon Cancer Screening Centre in Calgary, Canada was conducted. Physical activity levels and ST were characterized using hours of rMVPA, meeting cancer prevention recommendations (≥150 mins/wk of rMVPA) and hours of ST using self-reported data from the Long Form International Physical Activity Questionnaire. Unconditional logistic regression models were used to estimate the crude and adjusted odds ratios (OR) for presence of polyps associated with rMVP and ST. Results: Crude estimates for meeting cancer prevention guidelines (ORunadj=0.83, 95% CI: 0.70-0.98) and increasing rMVPA (ORunadj=0.75, 95% CI: 0.60-0.93 for 1-3 hrs/wk vs. 0) were associated with lower odds of having ≥1 polyp at screening. Effect estimates were attenuated in adjusted models. Threshold effects were observed for ST with significant associations observed for up to 20 hours/week of sitting time (ORadj per hour sitting=1.05, 95% CI: 1.01-1.09). Associations were strongest for rMVPA among females (ORadj=0.68, 95% CI: 0.48-0.97 for 1-3 hrs/wk vs. 0) and for ST among males (ORadj=1.74, 95% CI: 1.06-2.86 for 14-35hrs/wk of ST vs. 0-14 hrs/wk) Conclusions: In this large population undergoing colonoscopy screening for colorectal cancer, rMVPA was associated with reduced prevalence of polyps at screening, particularly among females. Even low amounts of regular ST (2-5hrs/day) were associated with the presence of polyps, particularly among males. Strategies aimed at reducing the amount of pre-carcinogenic colon lesions should combine increasing rMVPA and reducing ST. Citation Format: Darren R. Brenner, Demetra H. Yannitsos, Matthew Warkentin, Eileen Shaw, Nigel T. Brockton, S. Elizabeth McGregor, Susanna Town, Robert J. Hilsden. Recreational physical activity, sedentary time and the incidence of colorectal polyps in a screening population for colon cancer. [abstract]. In: Proceedings of the AACR Special Conference: Improving Cancer Risk Prediction for Prevention and Early Detection; Nov 16-19, 2016; Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(5 Suppl):Abstract nr B02.
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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 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".