Weight loss while preserving bone mineral density – possible?
Obesity is an alarmingly increasing global public health issue. Obesity is estimated to account for more than 20% of all annual health care expenditures in the United States. During the course of weight-loss, people are more than often concerned about its effect on their bone health. It is important to preserve bone mineral density to reduce the risks of fractures, while following weight loss routine.
Glucagon-like peptide-1 receptor agonists (GLP-1RA) are used in obesity management because they induce weight loss via appetite inhibition. Exercises and physical activities are also healthy means to lose weight while preserving or increasing lean body mass. A recent study published in JAMA open network has compared the effects of exercise and liraglutide, a GLP-1RA specifically on bone health during weight loss.
Study design
This randomized control trial was a predefined secondary analysis of effects of exercise alone, liraglutide, and both treatments combined for healthy weight loss maintenance.
Participants included were between 18-65 years old and were classified obese with BMI (body mass index) of 32-43. All participants underwent 8-week diet plan with 800 kcal/day initially followed by random assignment to a 1-year intervention phase with:
- either exercise and placebo (exercise group),
- liraglutide (liraglutide group),
- a combination of exercise and liraglutide (combination group), or
- placebo (placebo group)
Exercise intervention included 2-days of group and 2-days of individual sessions per week for 52 weeks. Group session consisted of 30-minute interval-based, vigorous intensity indoor cycling and 15-minute circuit training. Circuit training consisted of 5 vigorous-intensity muscle-strengthening exercises using body weight or external resistance for 3 circuits. For individual sessions, participants performed moderate to vigorous intensity exercise with self monitoring of heart rate (HR). Those in liraglutide only and placebo only group, were instructed to maintain usual physical activity throughout the trial.
Liraglutide or volume-matched placebo was started with 0.6 mg/day with weekly increments of 0.6 mg until reaching a dose of 3.0 mg/day.
Results
This study was conducted between August 2016 and November 2019 at the University of Copenhagen and Hvidovre Hospital in Denmark. A total of 195 participants (124 females [64%] and 71 males [36%]), were randomly assigned to 4 groups:
Significance in clinical practice
Exercise should almost always be considered to reduce the risk of fractures by preserving bone mineral density in people
- taking GLP-1RA treatment
- Undergoing gastric bypass
Limitations
As per the authors the research results may not be generalizable to wider/global population or those with co-morbidities. As bone mineral density was the secondary outcome, “the analyses were not adjusted for multiple comparisons”. Also, the heterogeneity of the sample may have increased variation of study results.
Author
Signe Sørensen Torekov, PhD, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark. The study was published on JAMA network open on June 25, 2024.