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Metrics of diabetes risk are only minimally improved by exercise training in postmenopausal breast cancer survivors

Citation

Viskochil, Richard (2020), Metrics of diabetes risk are only minimally improved by exercise training in postmenopausal breast cancer survivors, Dryad, Dataset, https://doi.org/10.5061/dryad.9cnp5hqdj

Abstract

Context

Insulin resistance is a risk factor for breast cancer recurrence. How exercise training changes fasting and post-glucose insulin resistance in breast cancer survivors is unknown.

Objective

To evaluate exercise-induced changes in post-glucose ingestion insulin concentrations, insulin resistance, and their associations with cancer-relevant biomarkers in breast cancer survivors.

Setting

The University of Massachusetts Kinesiology Department.

Participants

Fifteen postmenopausal breast cancer survivors not meeting the physical activity guidelines (150 minutes/week of exercise).

Intervention

a supervised 12-week aerobic exercise program (60 min/day, 3-4 days/week).

Main outcome measures

Post-glucose ingestion insulin was determined by peak insulin and area under the insulin curve (iAUC) during a five-sample oral glucose tolerance test. Insulin sensitivity was estimated from the Matsuda composite insulin sensitivity index (C-ISI). Changes in fitness and body composition were determined from submaximal VO2peak and dual energy X-ray absorptiometry (DEXA).

Results

Participants averaged 156.8±16.6 minutes/week of supervised exercise. Estimated VO2peak significantly increased (+2.8±1.4 ml/kg/min, p<0.05) and body weight significantly decreased (-1.1±0.8 kg, p<0.05) following the intervention. There were no differences in fasting insulin, iAUC, C-ISI or peak insulin following the intervention. Insulin was only significantly lower 120 minutes following glucose consumption (68.8 ± 34.5 vs. 56.2 ± 31.9 uU/ml, p<0.05), and there was a significant interaction with past/present aromatase inhibitor (AI) use for peak insulin (-11.99 (non-AI) vs +13.91 (AI) uU/mL) and iAUC (-24.03 (non-AI) vs +32.73 (AI) uU/mL).

Conclusions

Exercise training had limited overall benefits on insulin concentrations following glucose ingestion in breast cancer survivors but was strongly influenced by AI use.

Methods

The data represents plasma c-peptide and glucose concentrations collected during an oral glucose tolerance test. 

Funding

Rays of Hope Center for breast cancer research