Study to Weigh the Effect of Exercise Training on BONE quality and strength (SWEET BONE) in type 2 diabetes: study protocol for a randomised clinical trial

Abstract

Introduction: Type 2 diabetes (T2D) is associated with an increased fracture risk despite normal-to-increased bone mineral density, suggesting reduced bone quality. Exercise may be effective in reducing fracture risk by ameliorating muscle dysfunction and reducing risk of fall, though it is unclear whether it can improve bone quality.

Methods and analysis: The 'Study to Weigh the Effect of Exercise Training on BONE quality and strength (SWEET BONE) in T2D' is an open-label, assessor-blinded, randomised clinical trial comparing an exercise training programme of 2-year duration, specifically designed for improving bone quality and strength, with standard care in T2D individuals. Two hundred T2D patients aged 65-75 years will be randomised 1:1 to supervised exercise training or standard care, stratified by gender, age ≤ or >70 years and non-insulin or insulin treatment. The intervention consists of two weekly supervised sessions, each starting with 5 min of warm-up, followed by 20 min of aerobic training, 30 min of resistance training and 20 min of core stability, balance and flexibility training. Participants will wear weighted vests during aerobic and resistance training. The primary endpoint is baseline to end-of-study change in trabecular bone score, a parameter of bone quality consistently shown to be reduced in T2D. Secondary endpoints include changes in other potential measures of bone quality, as assessed by quantitative ultrasound and peripheral quantitative CT; bone mass; markers of bone turnover; muscle strength, mass and power; balance and gait. Falls and asymptomatic and symptomatic fractures will be evaluated over 7 years, including a 5-year post-trial follow-up. The superiority of the intervention will be assessed by comparing between-groups baseline to end-of-study changes.

Ethics and dissemination: This study was approved by the institutional ethics committee. Written informed consent will be obtained from all participants. The study results will be submitted for peer-reviewed publication.

Trial registration number: NCT02421393; Pre-results.

Keywords: bone fractures; bone mass; bone quality; exercise; physical fitness; type 2 diabetes.

Conflict of interest statement

Competing interests: None declared.

© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Figures

Figure 1

Study flow chart. DXA, dual‐energy X‐ray absorptiometry; LTPA, leisure time physical activity; MS, musculoskeletal; PASE, Physical Activity Scale for the Elderly; pQCT, peripheral quantitative; qUS, quantitative ultrasound.

Figure 2

Sequence of exercises during each supervised exercise training session. *Intensity of aerobic exercise will be adjusted according to improvements in predicted VO2max, as recorded every 6 months. †Intensity of resistance exercise will be adjusted according to improvements in 1-RM, as recorded every 6 months; new resistance exercises will be introduced every 12 weeks to maintain patient’s adherence, and the velocity of execution during the concentric phase of the movement will be progressively increased to enhance muscle power. ‡Height of jumps and amplitude of movements of weight-bearing exercise will be also progressively increased. §Difficulty level of balance training will be gradually increased by performing the exercises with closed eyes, reducing the support area, changing visual fixation (eg, head rotations), varying the centre of mass (eg, limb raising) or adding a manual or cognitive task. 1-RM, one-repetition maximum; VO2max, maximal oxygen consumption.