Exercise Dose Effects on Insulin Resistance Indicators in Postmenopausal Women: A Randomized Trial
Bibliographic record
Abstract
Background: While >= 150 minutes/week of moderate-vigorous physical activity is recommended for cancer prevention, the optimal amount for breast cancer prevention is unknown. Insulin resistance is a candidate biomarker of breast cancer risk. The objective of the study was to determine if 300 versus 150 minutes/week of moderate-vigorous aerobic exercise produces stronger improvements in insulin resistance indicators. Methods: The Breast Cancer and Exercise Trial in Alberta (BETA) was a year-long, two-center, two-armed, randomized controlled exercise trial between June 2010 and June 2013. The setting was a volunteer sample from Calgary and Edmonton, Canada. Participants were 400 inactive, non-diabetic, postmenopausal women with body mass index of 22 - 40 kg/m 2 . Interventions were 5 days/week aerobic exercise (3 days/week supervised) for 60 minutes/session (high) or 30 minutes/session (moderate) at 65-75% heart rate reserve for great-than or equal to 50% of each session. The main outcome measures were fasting blood concentrations of insulin, glucose, leptin, adiponectin, and resistin measured at baseline, 6 and 12 months. Results: Dose effects were evaluated using linear mixed models adjusted for baseline biomarker concentrations. High/moderate ratios of geometric mean biomarker concentrations over 12 months ranged from 0.93 to 1.00 (all P-values great-than or equal to 0.05), indicating no dose effect. Among adherent women (n = 137), ratios for insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and leptin were 0.77 - 0.89 (P-values < 0.05), indicating more benefit from the high prescription. There was a significant dose effect (P-value < 0.05) on resistin and leptin in non-obese and younger women, respectively. Conclusions: Prescribing 300 versus 150 minutes/week of moderate-vigorous aerobic exercise to inactive, non-diabetic, postmenopausal women may not produce stronger changes in insulin resistance indicators. Among exercise-adherers, however, a 300 minutes/week prescription might provide some additional benefit for breast cancer prevention. J Endocrinol Metab. 2016;6(2):35-45 doi: http://dx.doi.org/10.14740/jem341w
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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 | 0.003 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.003 | 0.003 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.006 | 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".