Weight Loss-Induced Reduction of Bone Mineral Density in Older Adults with Obesity

Medical weight loss in older persons with obesity

The prevalence of individuals with obesity or overweight has steadily increased over the past decades both worldwide, and in the United States. This trend is also evident in the older adult population, which has experienced a continuous rise in the number of individuals with overweight or obesity. This is relevant due to the impact of obesity in older adults' quality of life, physical function, morbidity, and healthcare costs. This review aims to provide practical guidance and currently available approaches for healthcare professionals in managing this population. Both non-pharmacological methods such as intensive behavioural therapy, nutritional interventions, and physical activity, as well as anti-obesity medications, are discussed, with a focus on their potential positive and negative effects in older adults. Additionally, bariatric therapy is evaluated, including current procedures available and the associated results and risks in the older population.

Effectiveness and safety of once-weekly semaglutide: findings from the SEMACOL-REAL retrospective multicentric observational study in Colombia

Introduction

Diabetes stands as one of the leading causes of death worldwide. Glucagon-like peptide-1 receptor agonists rank among the most effective medications for lowering blood glucose and body weight, as well as reducing cardiovascular risk in individuals with diabetes. Observational studies complement experimental evidence in new settings, different populations, and real-world healthcare practices.

Methods

A multicentric observational study of adults with type 2 diabetes treated with once-weekly subcutaneous semaglutide in four health centers in Colombia was conducted. The protocol for the present study was not pre-registered.

Results

Data from 186 patients were included. Most patients were women (57%) with a mean age of 62.8 ± 12.1 years. One year of once-weekly semaglutide usage was associated with a mean reduction in HbA1C of -1.47% (95% CI -1.76, -1.17), weight loss of -4.23 kg (95% CI -5.34, -3.12), and albumin/creatinine ratio of -18.6 mg/g (95% CI -60.2, -5.9). Approximately half the treated patients achieved a level of HbA1c ≤7% by the end of follow-up. Adverse events were rare and consistent with clinical trial safety profiles.

Conclusion

In Colombia, administering semaglutide subcutaneously once a week over a 1-year period led to an average weight loss of 4.2 kg and a decrease of 1.4% in HbA1c.

Caloric restriction reduces trabecular bone loss during aging and improves bone marrow adipocyte endocrine function in male mice

Introduction

Caloric restriction (CR) is a nutritional intervention that increases life expectancy while lowering the risk for cardio-metabolic disease. Its effects on bone health, however, remain controversial. For instance, CR has been linked to increased accumulation of bone marrow adipose tissue (BMAT) in long bones, a process thought to elicit detrimental effects on bone. Qualitative differences have been reported in BMAT in relation to its specific anatomical localization, subdividing it into physiological and potentially pathological BMAT. We here examine the local impact of CR on bone composition, microstructure and its endocrine profile in the context of aging.

Methods

Young and aged male C57Bl6J mice were subjected to CR for 8 weeks and were compared to age-matched littermates with free food access. We assessed bone microstructure and BMAT by micro-CT, bone fatty acid and transcriptomic profiles, and bone healing.

Results

CR increased tibial BMAT accumulation and adipogenic gene expression. CR also resulted in elevated fatty acid desaturation in the proximal and mid-shaft regions of the tibia, thus more closely resembling the biochemical lipid profile of the distally located, physiological BMAT. In aged mice, CR attenuated trabecular bone loss, suggesting that CR may revert some aspects of age-related bone dysfunction. Cortical bone, however, was decreased in young mice on CR and remained reduced in aged mice, irrespective of dietary intervention. No negative effects of CR on bone regeneration were evident in either young or aged mice.

Discussion

Our findings indicate that the timing of CR is critical and may exert detrimental effects on bone biology if administered during a phase of active skeletal growth. Conversely, CR exerts positive effects on trabecular bone structure in the context of aging, which occurs despite substantial accumulation of BMAT. These data suggest that the endocrine profile of BMAT, rather than its fatty acid composition, contributes to healthy bone maintenance in aged mice.

Bone Health After Exercise Alone, GLP-1 Receptor Agonist Treatment, or Combination Treatment: A Secondary Analysis of a Randomized Clinical Trial

Importance

A major concern with weight loss is concomitant bone loss. Exercise and glucagon-like peptide-1 receptor agonists (GLP-1RAs) represent weight loss strategies that may protect bone mass despite weight loss.

Objective

To investigate bone health at clinically relevant sites (hip, spine, and forearm) after diet-induced weight loss followed by a 1-year intervention with exercise, liraglutide, or both combined.

Design, Setting, and Participants

This study was a predefined secondary analysis of a randomized clinical trial conducted between August 2016 and November 2019 at the University of Copenhagen and Hvidovre Hospital in Denmark. Eligible participants included adults aged 18 to 65 years with obesity (body mass index of 32-43) and without diabetes. Data analysis was conducted from March to April 2023, with additional analysis in February 2024 during revision.

Interventions

After an 8-week low-calorie diet (800 kcal/day), participants were randomized to 1 of 4 groups for 52 weeks: a moderate- to vigorous-intensity exercise program (exercise alone), 3.0 mg daily of the GLP-1 RA liraglutide (liraglutide alone), the combination, or placebo.

Main Outcomes and Measures

The primary outcome was change in site-specific bone mineral density (BMD) at the hip, lumbar spine, and distal forearm from before the low-calorie diet to the end of treatment, measured by dual-energy x-ray absorptiometry in the intention-to-treat population.

Results

In total, 195 participants (mean [SD] age, 42.84 [11.87] years; 124 female [64%] and 71 male [36%]; mean [SD] BMI, 37.00 [2.92]) were randomized, with 48 participants in the exercise group, 49 participants in the liraglutide group, 49 participants in the combination group, and 49 participants in the placebo group. The total estimated mean change in weight losses during the study was 7.03 kg (95% CI, 4.25-9.80 kg) in the placebo group, 11.19 kg (95% CI, 8.40-13.99 kg) in the exercise group, 13.74 kg (95% CI, 11.04-16.44 kg) in the liraglutide group, and 16.88 kg (95% CI, 14.23-19.54 kg) in the combination group. In the combination group, BMD was unchanged compared with the placebo group at the hip (mean change, -0.006 g/cm2; 95% CI, -0.017 to 0.004 g/cm2; P = .24) and lumbar spine (-0.010 g/cm2; 95% CI, -0.025 to 0.005 g/cm2; P = .20). Compared with the exercise group, BMD decreased for the liraglutide group at the hip (mean change, -0.013 g/cm2; 95% CI, -0.024 to -0.001 g/cm2; P = .03) and spine (mean change, -0.016 g/cm2; 95% CI, -0.032 to -0.001 g/cm2; P = .04).

Conclusions and Relevance

In this randomized clinical trial, the combination of exercise and GLP-1RA (liraglutide) was the most effective weight loss strategy while preserving bone health. Liraglutide treatment alone reduced BMD at clinically relevant sites more than exercise alone despite similar weight loss.

Trial Registration

EudraCT: 2015-005585-32.

Sarcopenic obesity in older adults: a clinical overview

Sarcopenic obesity is characterized by a concurrent decline in muscle mass and function, along with increased adipose tissue. Sarcopenic obesity is a growing concern in older adults owing to significant health consequences, including implications for mortality, comorbidities and risk of developing geriatric syndromes. A 2022 consensus statement established a new definition and diagnostic criteria for sarcopenic obesity. The pathophysiology of this condition involves a complex interplay between muscle, adipose tissue, hormonal changes, inflammation, oxidative stress and lifestyle factors, among others. Sarcopenic obesity is treated with a range of management approaches, such as lifestyle interventions, exercise, nutrition and medical therapies. Emerging therapies that were developed for treating other conditions may be relevant to sarcopenic obesity, including novel pharmacological agents and personalized approaches such as precision medicine. In this Review, we synthesize the current knowledge of the clinical importance of sarcopenic obesity, its assessment and diagnosis, along with current and emerging management strategies.

Targeting Energy Intake and Circadian Biology to Engage Mechanisms of Aging in Older Adults With Obesity: Calorie Restriction and Time-Restricted Eating

With the rise in obesity across age groups, it has been a hindrance to engaging in physical activity and mobility in older adults. Daily calorie restriction (CR) up to 25% has been the cornerstone of obesity management even though the safety in older adults remains incompletely understood. Although some adults can follow CR with clinically significant weight loss and improved health metrics, CR faces 2 obstacles-many fail to adopt CR and even among those who can adopt it short term, long-term compliance can be difficult. Furthermore, there is a continuing debate about the net benefits of CR-induced weight loss in older adults because of the concern that CR may worsen sarcopenia, osteopenia, and frailty. The science of circadian rhythm and its plasticity toward the timing of nutrition offer promise to alleviate some challenges of CR. The new concept of Time-Restricted Feeding/Eating (TRF for animal studies and TRE for human studies) can be an actionable approach to sustaining the circadian regulation of physiology, metabolism, and behavior. TRE can often (not always) lead to CR. Hence, the combined effect of TRE through circadian optimization and CR can potentially reduce weight and improve cardiometabolic and functional health while lessening the detrimental effects of CR. However, the science and efficacy of TRE as a sustainable lifestyle in humans are in its infancy, whereas animal studies have offered many desirable outcomes and underlying mechanisms. In this article, we will discuss the scope and opportunities to combine CR, exercise, and TRE to improve functional capacity among older adults with obesity.

Pre-flight body weight effects on urinary calcium excretion in space

Microgravity-induced bone loss increases urinary calcium excretion which increases kidney stone formation risk. Not all individuals show the same degree of increase in urinary calcium and some pre-flight characteristics may help identify individuals who may benefit from in-flight monitoring. In weightlessness the bone is unloaded, and the effect of this unloading may be greater for those who weigh more. We studied whether pre-flight body weight was associated with increased in-flight urinary calcium excretion using data from Skylab and the International Space Station (ISS). The study was reviewed and approved by the National Aeronautics and Space Administration (NASA) electronic Institutional Review Board (eIRB) and data were sourced from the Longitudinal Study of Astronaut Health (LSAH) database. The combined Skylab and ISS data included 45 participants (9 Skylab, 36 ISS). Both weight and day in flight were positively related to urinary calcium excretion. There was also an interaction between weight and day in flight with higher weight associated with higher calcium excretion earlier in the mission. This study shows that pre-flight weight is also a factor and could be included in the risk assessments for bone loss and kidney stone formation in space.

Effect of exercise modality and weight loss on changes in muscle and bone quality in older adults with obesity

BACKGROUND

Little is known about the effect of exercise modality during a dietary weight loss program on muscle size and quality, as measured by computed tomography (CT). Even less is known about how CT-derived changes in muscle track with changes in volumetric bone mineral density (vBMD) and bone strength.

METHODS

Older adults (66 ± 5 years, 64 % women) were randomized to 18-months of diet-induced weight loss (WL), WL with aerobic training (WL + AT), or WL with resistance training (WL + RT). CT-derived muscle area, radio-attenuation and intermuscular fat percentage at the trunk and mid-thigh were determined at baseline (n = 55) and 18-month follow-up (n = 22-34), and changes were adjusted for sex, baseline value, and weight lost. Lumbar spine and hip vBMD and finite element-derived bone strength were also measured.

RESULTS

After adjustment for the weight lost, muscle area losses at the trunk were -7.82 cm2 [-12.30, -3.35] for WL, -7.72 cm2 [-11.36, -4.07] for WL + AT, and -5.14 cm2 [-8.65, -1.63] for WL + RT (p < 0.001 for group differences). At the mid-thigh, decreases were -6.20 cm2 [-10.39, -2.02] for WL, -7.84 cm2 [-11.19, -4.48] for WL + AT, and -0.60 cm2 [-4.14, 2.94] for WL + RT; this difference between WL + AT and WL + RT was significant in post-hoc testing (p = 0.01). Change in trunk muscle radio-attenuation was positively associated with change in lumbar bone strength (r = 0.41, p = 0.04).

CONCLUSIONS

WL + RT better preserved muscle area and improved muscle quality more consistently than WL + AT or WL alone. More research is needed to characterize the associations between muscle and bone quality in older adults undertaking weight loss interventions.

Weight Loss Interventions and Skeletal Health in Persons with Diabetes

PURPOSE OF REVIEW

Weight loss is recommended for improving glycemic control and reducing cardiovascular risk factors in persons with diabetes. However, both diabetes and weight loss have been associated with detrimental skeletal health. This review aims to summarize recent study findings on the effects of lifestyle interventions for weight loss on skeletal health among persons with type 2 diabetes (T2D).

RECENT FINDINGS

A few large-scale observational studies have demonstrated an increased fragility fracture risk associated with weight loss among persons with T2D. Randomized control trials in persons with T2D also have shown that intentional lifestyle interventions for weight loss are associated with a greater decrease in bone mineral density (BMD) and an increase in the risk of fracture. The biological mechanisms underlying the compromised bone health during lifestyle interventions for weight loss are complex and not yet conclusive. However, there is evidence to suggest that bone loss and increased fracture risk during intentional weight loss may be mitigated by some intervention approaches, such as high protein intake, calcium supplementation, and resistance and balance training. There is still a lack of studies investigating the effects of different interventions for weight loss on skeletal health among persons with T2D. However, certain types of diet and physical activity intervention combined with bone monitoring and fracture risk prediction may help achieve weight loss goals and maintain skeletal health among persons with T2D during intentional weight loss.

Outcomes addressed in randomized controlled lifestyle intervention trials in community-dwelling older people with (sarcopenic) obesity-An evidence map

Obesity and sarcopenic obesity (SO) are characterized by excess body fat with or without low muscle mass affecting bio-psycho-social health, functioning, and subsequently quality of life in older adults. We mapped outcomes addressed in randomized controlled trials (RCTs) on lifestyle interventions in community-dwelling older people with (sarcopenic) obesity. Systematic searches in Medline, Embase, Cochrane Central, CINAHL, PsycInfo, Web of Science were conducted. Two reviewers independently performed screening and extracted data on outcomes, outcome domains, assessment methods, units, and measurement time. A bubble chart and heat maps were generated to visually display results. Fifty-four RCTs (7 in SO) reporting 464 outcomes in the outcome domains: physical function (n = 42), body composition/anthropometry (n = 120), biomarkers (n = 190), physiological (n = 30), psychological (n = 47), quality of life (n = 14), pain (n = 4), sleep (n = 2), medications (n = 3), and risk of adverse health events (n = 5) were included. Heterogeneity in terms of outcome definition, assessment methods, measurement units, and measurement times was found. Psychological and quality of life domains were investigated in a minority of studies. There is almost no information beyond 52 weeks. This evidence map is the first step of a harmonization process to improve comparability of RCTs in older people with (sarcopenic) obesity and facilitate the derivation of evidence-based clinical decisions.

Implication of diet and exercise on the management of age‐related sarcopenic obesity in Asians

The incidence of sarcopenic obesity among adults aged ≥65 years is rising worldwide. Sarcopenic obesity is a high‐risk geriatric syndrome defined as a gain in the amount of adipose tissue along with the age‐related loss of muscle mass and strength or physical performance. Sarcopenic obesity is associated with increased risks of falls, physical limitations, cardiovascular diseases, metabolic diseases, and/or mortality. Thus, the identification of preventive and treatment strategies against sarcopenic obesity is important for healthy aging. Diet and exercise are the reasons for the development of sarcopenic obesity and are key targets in its prevention and treatment. Regarding weight reduction alone, it is most effective to maintain a negative energy balance with dietary calorie restriction and aerobic exercise. However, it is important to preserve skeletal muscle mass while reducing fat mass. Resistance exercise and appropriate protein supply are the main ways of preserving skeletal muscle mass, as well as muscle function. Therefore, in order to improve sarcopenic obesity, a complex treatment strategy is needed to limit energy ingestion with proper nutrition and to increase multimodal exercises. In this review, we focus on recently updated interventions for diet and exercise and potential future management strategies for Asian individuals with aging‐related sarcopenic obesity. Geriatr Gerontol Int 2022; 22: 695–704.

Secondary Osteoporosis and Metabolic Bone Diseases

Fragility fracture is a worldwide problem and a main cause of disability and impaired quality of life. It is primarily caused by osteoporosis, characterized by impaired bone quantity and or quality. Proper diagnosis of osteoporosis is essential for prevention of fragility fractures. Osteoporosis can be primary in postmenopausal women because of estrogen deficiency. Secondary forms of osteoporosis are not uncommon in both men and women. Most systemic illnesses and organ dysfunction can lead to osteoporosis. The kidney plays a crucial role in maintaining physiological bone homeostasis by controlling minerals, electrolytes, acid-base, vitamin D and parathyroid function. Chronic kidney disease with its uremic milieu disturbs this balance, leading to renal osteodystrophy. Diabetes mellitus represents the most common secondary cause of osteoporosis. Thyroid and parathyroid disorders can dysregulate the osteoblast/osteoclast functions. Gastrointestinal disorders, malnutrition and malabsorption can result in mineral and vitamin D deficiencies and bone loss. Patients with chronic liver disease have a higher risk of fracture due to hepatic osteodystrophy. Proinflammatory cytokines in infectious, autoimmune, and hematological disorders can stimulate osteoclastogenesis, leading to osteoporosis. Moreover, drug-induced osteoporosis is not uncommon. In this review, we focus on causes, pathogenesis, and management of secondary osteoporosis.

Associations of variability in body weight and glucose levels with the risk of hip fracture in people with diabetes

BACKGROUND

Diabetes is associated with a high risk of fragility fracture. However, there are controversies regarding the effect of fluctuations in metabolic parameters on the risk of fracture. We aimed to investigate the associations of body weight or glucose variability or their combination with the risk of hip fracture in people with diabetes.

METHODS

A population-based cohort study with 480,539 subjects over 40 years who had undergone three or more health examinations was performed. The degree of variability was evaluated using variability independent of the mean (VIM, 100 × standard deviation / mean^beta), coefficient of variation (CV), and average real variability (ARV, average of the absolute differences between consecutive values). High variability was defined as having values in the highest quartile. Cox proportional hazards models were used to estimate the risk of hip fracture.

RESULTS

There were 2834 hip fracture events (0.59%) during the mean follow-up of 8.1 years. After multivariable adjustment for age, sex, alcohol consumption, smoking, regular exercise, income, glucose, body mass index, hemoglobin, estimated glomerular filtration rate, diabetes duration, diabetes treatment with multiple agents, and osteoporosis, the HRs (95% CI) of hip fracture were 1.36 (1.24-1.50) and 1.29 (1.16-1.43) for high body weight VIM and high glucose VIM, respectively. The HR (95% CI) of both high VIM group was 1.63 (1.44-1.83), suggesting an additive effect of variabilities in body weight and glucose. The results were consistent when using CV and ARV and in various sensitivity analyses.

CONCLUSIONS

High variability in body weight and glucose levels is associated with an increased incidence rate and risk of hip fracture in people with diabetes.

Retrospective analysis of the relationship between bone mineral density and body composition in a health check-up Chinese population

PURPOSE

This study was designed to explore the relationship between bone mineral density (BMD) and body composition indicators in Chinese adults (≥50 years) in order to provide a scientific basis for optimal bone health management.

METHOD

Individuals ≥50 years old who received physical examinations and routine check-ups at the Health Management Research Institute of PLA General Hospital from September 2014 through March 2022 were included as research subjects in this study. Basic clinical and demographic information were recorded for all subjects, along with smoking and drinking status, height and body weight. A panel of routine blood chemistry and metabolite markers were measured, along with lean muscle mass and body fat mass using body composition bioelectrical impedance analysis (BIA). Body mass index (BMI), body fat percentage (BFP), skeletal muscle mass index (SMI), and bone mineral density (BMD) were calculated for all individuals. For comparative analysis, individuals were grouped based on their BMI, BFP, SMI and BMD T-score. Follow-up examinations were performed in a cohort of 1,608 individuals matched for age, sex, smoking and drinking history for ≥5 years.

RESULTS

In this large cross-sectional study, age, smoking, homocysteine (Hcy) and blood glucose levels were established as independent risk factors for osteoporosis. Multi-factor logistic regression analysis showed that age, sex, BMI, intact parathyroid hormone (iPTH), SMI, BFP, smoking, blood levels of inorganic phosphate (P) and K+ were all significantly associated with osteoporosis risk (P<0.05). A subset of these factors- BMI, SMI, BFP and K+, were determined to be protective. In the cohort followed for ≥5 years, SMI and BMD decreased while BFP and BMI increased significantly (P<0.001) over time.

CONCLUSION

Risk of osteoporosis may be reduced by increasing body weight, particularly lean muscle mass, while simultaneously controlling BFP.

The association between muscle indicators and bone mass density and related risk factors in the diabetic elderly population: Bushehr Elderly Health (BEH) Program

BACKGROUND

Loss of muscle mass and strength and bone mass density are complications of the aging process. Studies show that the prevalence of sarcopenia and osteoporosis may be higher in patients with diabetes. Therefore, this study was aimed to investigate the relationship between muscle mass and strength indices and bone mass density in diabetic elderly.

MATERIALS AND METHODS

This cross-sectional study was conducted based on the data collected during the Bushehr Elderly Health (BEH) Program, stage II. Diabetes was defined as FPG ≥ 126 mg/dl or HbA1C ≥ 6.5 or taking anti-diabetic medication. Dual x-ray absorptiometry (DXA, Discovery WI, Hologic Inc, USA) was used to measure bone mineral density, fat mass, trabecular bone score (TBS) and muscle mass. Muscle strength was measured by grip strength.Osteoporosis was defined as the bone mineral density of ≥ 2.5 standard deviations (SD) below the average value of young normal adults (T-score of ≤ -2.5 SD) in the femoral neck, or lumbar spine (L1-L4) or total hip. To determine the relationship between skeletal muscle index (SMI) and muscle strength on bone status in a continuous scale was used from linear regression. To estimate the effect of SMI and muscle strength on osteoporosis was used from modified Poisson regression for analysis.

RESULTS

This study included 759 diabetic elderly with a mean age of 68.6 years and 56.9% of them were women. Skeletal muscle index (SMI) was related to all sites of BMDs and TBS L1-L4 after adjusted in full models (P-value < 0.001). The largest coefficients were observed for BMD L1-L4 in all models (β: 0.043 g/cm2; 95% CI: 0.030-0.057 in full model). Muscle strength was also associated with BMDs and TBS. Only, in model 2 (adjustments for age and sex effect), there was no significant relationship between muscle strength and BMD L1-L4 and TBS L1-L4. The strongest associations were observed for the total hip BMD and muscle strength (β: 0.034 g/cm2; 95% CI: 0.022- 0.046 in full model). Also, increased SMI and muscle strength was associated with decreased osteoporosis in crude and adjusted models (P < 0.001).

CONCLUSIONS

In this study, it was revealed that the reduction of SMI in elderly patients with diabetes was significantly associated with decreased BMD and TBS. The muscle strength was also associated with BMD and TBS. So, muscle strength and muscle mass should be measured separately ever since both are independently associated with BMD and TBS. Muscle strength and muscle mass were negatively associated with osteoporosis in older people with diabetes. Thus, we should pay more attention to muscle strength training in older people with diabetes, particularly in osteoporotic patients.

Bone Mineral Density Changes during Weight Regain following Weight Loss with and without Exercise

The purpose of this study was to compare changes in bone mineral density (BMD) over a 6 month follow up (period of weight regain) in overweight, postmenopausal women having previously completed a 6 month weight loss (WL) intervention with and without aerobic exercise (AEX). Women (BMI > 25 kg/m²) underwent VO₂max and DEXA scans at baseline, after 6 months of WL or AEX + WL, and at 12 months ad libitum follow up. Both groups lost ~9% body weight from 0 to 6 months and regained ~2% from 6 to 12 months, while losing ~4% of appendicular lean mass (ALM) across the 12-month study duration. VO₂max increased 10% from 0 to 6 months and declined 12% from 6 to 12 months for AEX + WL, with no changes for WL. Total body (p < 0.01) and total femur (p = 0.03) BMD decreased similar between groups across time (combined groups: 0-6 months: total body: -1.2% and total femur: -1.2%; 6-12 months: total body: -0.26% and total femur: -0.09%). Less ALM loss and greater VO₂max increases during the WL phase were associated with attenuated BMD loss at various anatomical sites during periods of weight regain (6-12 months) p's < 0.05). Results suggest that BMD loss may continue following WL, despite weight regain. Further, this study adds to the literature by suggesting that preventing declines in muscle quality and function during WL may attenuate the loss of BMD during weight regain. Future studies are needed to identify mechanisms underlying WL-induced bone loss so that effective practices can be designed to minimize the loss of BMD during WL and weight maintenance in older women.

Group Lifestyle Phone Maintenance for Weight, Health, and Physical Function in Adults Aged 65-80 Years: A Randomized Clinical Trial

BACKGROUND

Group lifestyle sessions with phone maintenance could improve weight, health, and function in vulnerable older adults.

METHODS

Community-dwelling adults (N = 322) with body mass index (BMI, kg/m2) ≥27 and additional risk factors received 12 one-hour in-person behavioral weight management group sessions then were randomized to 8 half-hour telephone sessions (n = 162) or newsletter control (n = 160) from 4 to 12 months with no treatment contact thereafter. Primary outcome was 0- to 12-month weight change. Cardiometabolic, short physical performance battery (SPPB), and self-reported activity changes were assessed at 12 and 24 months.

RESULTS

At baseline, the mean (SD) age was 71.2 (4.3) and BMI was 33.8 (5.1). Participants were 77% women, 13% Black, 85% retired, averaging 4 medical conditions, and taking blood pressure (67.4%) and lipid-lowering (51.6%) medications. At 12 months, a greater proportion of the phone group (66.0%) achieved ≥5% weight loss compared with newsletter control (53.2%; p = .02). Mean (95% CI) weight loss was greater for phone (-6.6 kg [-7.5, -5.8]) than newsletter (-5.1 kg [-7.2, -3.0]); p = .01. Modest lipid, glucose, and blood pressure improvements were found, but did not differ significantly between groups. Small SPPB and activity improvements were maintained at 12 and 24 months in both groups.

CONCLUSIONS

Brief phone contacts compared to newsletters enhanced weight loss maintenance among older high-risk adults at 1 year, but not cardiometabolic outcomes. Modest functional improvements were observed in both. Lower-intensity maintenance contacts (phone or newsletter) for weight, health, and physical function in older adults warrant further study.

CLINICAL TRIALS REGISTRATION NUMBER

NCT03192475.

Genetically determined SCFA concentration modifies the association of dietary fiber intake with changes in bone mineral density during weight loss: The Preventing Overweight Using Novel Dietary Strategies (POUNDS LOST) trial

BACKGROUND

SCFAs are involved in regulation of body weight and bone health.

OBJECTIVES

We aimed to examine whether genetic variations related to butyrate modified the relation between dietary fiber intake and changes in bone mineral density (BMD) in response to weight-loss dietary interventions.

METHODS

In the 2-y Preventing Overweight Using Novel Dietary Strategies trial, 424 participants with BMD measured by DXA scan were randomly assigned to 1 of 4 diets varying in macronutrient intakes. A polygenic score (PGS) was calculated based on 7 genetic variants related to the production of butyrate for 370 of the 424 participants.

RESULTS

SCFA PGS significantly modified the association between baseline dietary fiber intake and sex on 2-y changes in whole-body BMD (P-interaction = 0.049 and 0.008). In participants with the highest tertile of SCFA PGS, higher dietary fiber intake was related to a greater increase in BMD (β:  0.0022; 95% CI: 0.0009, 0.0035; P = 0.002), whereas no such association was found for participants in the lower tertiles. In the lowest tertiles of SCFA PGS, men showed a significant increase in whole-body BMD (β: 0.0280; 95% CI: 0.0112, 0.0447; P = 0.002) compared with women. In the highest tertile, no significant difference was found for the change in BMD between men and women.

CONCLUSIONS

Our data indicate that genetic variants related to butyrate modify the relations of dietary fiber intake and sex with long-term changes in BMD in response to weight-loss diet interventions.

Preclinical models for investigating how bone marrow adipocytes influence bone and hematopoietic cellularity

Laboratory mice are a crucial preclinical model system for investigating bone marrow adipocyte (BMAd)-bone and BMAd-hematopoiesis interactions. In this review, we evaluate the suitability of mice to model common human diseases related to osteopenia or hematopoietic disorders, point out consistencies and discrepancies among different studies, and provide insights into model selection. Species, age, sex, skeletal site, and treatment protocol should all be considered when designing future studies.

Prediabetes screening: Questionable benefits in the golden years

Irrespective of the definition and diagnostic criteria used, the term prediabetes denotes a state of dysmetabolism with a high risk of progression to diabetes mellitus. Although diabetes-related complications may already be evident among individuals with prediabetes, interventions at this stage primarily aim to hinder the development of overt hyperglycemia rather than to prevent complications. Current recommendations for prediabetes testing are common across all adult age categories. Recent evidence arising from the prospective investigation of the natural course of prediabetes among elderly individuals pose questions regarding the benefits of meticulous prediabetes screening in this age group. In view of this and due to the lack of sufficient data to concretely support a positive impact of further preventive strategies among older individuals, screening recommendations should be reevaluated to target selected elderly individuals who are most likely to benefit in terms of quality of life and prognosis. Further therapeutic measures should be tailored to the inherent features of this frail age group, in order to exert a meaningful effect on overall health status.

Rationale and Design for a Higher (Dairy) Protein Weight Loss Intervention That Promotes Muscle Quality and Bone Health in Older Adults with Obesity: A Randomized, Controlled Pilot Study

In contrast to recommendations for young and middle-aged adults, intentional weight loss among older adults remains controversial and is inconsistently advised. Recent research suggests that a higher protein diet can mitigate loss of lean mass during periods of intentional weight loss among older adults with obesity; however, the effects of intentional weight loss on skeletal muscle and bone are not fully understood. The Dairy in the Diet Yields New Approaches for Muscle Optimization (DDYNAMO) trial is a 6-month, randomized, controlled pilot study assessing the effects of combining regular, generous intakes of high quality protein (30 g/meal; primarily from dairy) with caloric restriction (-500kcal/d) and low-intensity resistance exercise (30 min/3 times per week) on muscle quality, muscle composition, bone mineral density in men and women aged ≥60 years with obesity and mild to moderate functional impairment (Short Physical Performance Battery [SPPB] score ≥4 to ≤10). Participants will be re-assessed at 18 months to evaluate weight maintenance, bone mineral density, physical function, and other secondary measures. ClinicalTrials.gov Identifier: NCT02437643.

Testosterone Replacement Therapy Added to Intensive Lifestyle Intervention in Older Men With Obesity and Hypogonadism

BACKGROUND

Obesity and hypogonadism additively contribute to frailty in older men; however, appropriate treatment remains controversial.

OBJECTIVE

Determine whether testosterone replacement augments the effect of lifestyle therapy on physical function in older men with obesity and hypogonadism.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

VA Medical Center.

PARTICIPANTS

83 older (age ≥65 years) men with obesity (body mass index ≥30 kg/m2) and persistently low am testosterone (<10.4 nmol/L) associated with frailty.

INTERVENTIONS

Participants were randomized to lifestyle therapy (weight management and exercise training) plus either testosterone (LT+Test) or placebo (LT+Pbo) for 6 months.

OUTCOME MEASURES

Primary outcome was change in Physical Performance Test (PPT) score. Secondary outcomes included other frailty measures, body composition, hip bone mineral density (BMD), physical functions, hematocrit, prostate specific antigen (PSA), and sex hormones.

RESULTS

PPT score increased similarly in LT+Test and LT+Pbo group (17% vs. 16%; P = 0.58). VO2peak increased more in LT+Test than LT+Pbo (23% vs. 16%; P = 0.03). Despite similar -9% weight loss, lean body mass and thigh muscle volume decreased less in LT+Test than LT+Pbo (-2% vs. -3%; P = 0.01 and -2% vs -4%; P = 0.04). Hip BMD was preserved in LT+Test compared with LT+Pbo (0.5% vs -1.1%; P = 0.003). Strength increased similarly in LT+Test and LT+Pbo (23% vs 22%; P = 0.94). Hematocrit but not PSA increased more in LT+Test than LT+Pbo (5% vs 1%; P < 0.001). Testosterone levels increased more in LT+Test than LT+Pbo (167% vs 27%; P < 0.001).

CONCLUSION

In older, obese hypogonadal men, adding testosterone for 6 months to lifestyle therapy does not further improve overall physical function. However, our findings suggest that testosterone may attenuate the weight loss-induced reduction in muscle mass and hip BMD and may further improve aerobic capacity.

Age-Related Skeletal Muscle Dysfunction Is Aggravated by Obesity: An Investigation of Contractile Function, Implications and Treatment

Obesity is a global epidemic and coupled with the unprecedented growth of the world's older adult population, a growing number of individuals are both old and obese. Whilst both ageing and obesity are associated with an increased prevalence of chronic health conditions and a substantial economic burden, evidence suggests that the coincident effects exacerbate negative health outcomes. A significant contributor to such detrimental effects may be the reduction in the contractile performance of skeletal muscle, given that poor muscle function is related to chronic disease, poor quality of life and all-cause mortality. Whilst the effects of ageing and obesity independently on skeletal muscle function have been investigated, the combined effects are yet to be thoroughly explored. Given the importance of skeletal muscle to whole-body health and physical function, the present study sought to provide a review of the literature to: (1) summarise the effect of obesity on the age-induced reduction in skeletal muscle contractile function; (2) understand whether obesity effects on skeletal muscle are similar in young and old muscle; (3) consider the consequences of these changes to whole-body functional performance; (4) outline important future work along with the potential for targeted intervention strategies to mitigate potential detrimental effects.

Exploring the Impact of Obesity on Skeletal Muscle Function in Older Age

Sarcopenia is of important clinical relevance for loss of independence in older adults. The prevalence of obesity in combination with sarcopenia ("sarcopenic-obesity") is increasing at a rapid rate. However, whilst the development of sarcopenia is understood to be multi-factorial and harmful to health, the role of obesity from a protective and damaging perspective on skeletal muscle in aging, is poorly understood. Specifically, the presence of obesity in older age may be accompanied by a greater volume of skeletal muscle mass in weight-bearing muscles compared with lean older individuals, despite impaired physical function and resistance to anabolic stimuli. Collectively, these findings support a potential paradox in which obesity may protect skeletal muscle mass in older age. One explanation for these paradoxical findings may be that the anabolic response to weight-bearing activity could be greater in obese vs. lean older individuals due to a larger mechanical stimulus, compensating for the heightened muscle anabolic resistance. However, it is likely that there is a complex interplay between muscle, adipose, and external influences in the aging process that are ultimately harmful to health in the long-term. This narrative briefly explores some of the potential mechanisms regulating changes in skeletal muscle mass and function in aging combined with obesity and the interplay with sarcopenia, with a particular focus on muscle morphology and the regulation of muscle proteostasis. In addition, whilst highly complex, we attempt to provide an updated summary for the role of obesity from a protective and damaging perspective on muscle mass and function in older age. We conclude with a brief discussion on treatment of sarcopenia and obesity and a summary of future directions for this research field.

Dietary weight-loss interventions for the management of obesity in older adults

The obesity epidemic has reached old age in most industrialized countries, but trials elucidating the benefits and risks of weight reduction in older adults above 70 years of age with obesity remain scarce. While some findings demonstrate a reduced risk of mortality and other negative health outcomes in older individuals with overweight and mild obesity (i.e. body mass index (BMI) < 35 kg/m²), other recent research indicates that voluntary weight loss can positively affect diverse health outcomes in older individuals with overweight and obesity (BMI > 27 kg/m²), especially when combined with exercise. However, in this age group weight reduction is usually associated with a reduction of muscle mass and bone mineral density. Since uncertainty persists as to which level overweight or obesity might be tolerable (or even beneficial) for older persons, current recommendations are to consider weight reducing diets only for older persons that are obese (BMI ≥ 30 kg/m²) and have weight-related health problems. Precise treatment modalities (e.g. appropriate level of caloric restriction and indicated dietary composition, such as specific dietary patterns or optimal protein content) as well as the most effective and safest way of adding exercise are still under research. Moreover, the long-term effects of weight-reducing interventions in older individuals remain to be clarified, and dietary concepts that work for older adults who are unable or unwilling to exercise are required. In conclusion, further research is needed to elucidate which interventions are effective in reducing obesity-related health risks in older adults without causing relevant harm in this vulnerable population.

Association of Bariatric Surgery With Risk of Fracture in Patients With Severe Obesity

IMPORTANCE

Given the complex relationship between body mass index, body composition, and bone density and the correlative nature of the studies that have established the prevailing notion that higher body mass indices may be protective against osteopenia and osteoporosis and, therefore, fracture, the absolute risk of fracture in patients with severe obesity who undergo either Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) compared with those who do not undergo bariatric surgery is unknown.

OBJECTIVE

To assess the rates of fractures associated with obesity and compare rates between those who do not undergo bariatric surgery, those who undergo RYGB, and those who undergo SG.

DESIGN, SETTING, AND PARTICIPANTS

In this retrospective multicenter cohort study of Medicare Standard Analytic Files derived from Medicare parts A and B records from January 2004 to December 2014, patients classified as eligible for bariatric surgery using the US Centers of Medicare & Medicaid criteria who either did not undergo bariatric surgery or underwent RYGB or SG were exactly matched in a 1:1 fashion based on their age, sex, Elixhauser Comorbidity Index, hypertension, smoking status, nonalcoholic fatty liver disease, hyperlipidemia, type 2 diabetes, osteoporosis, osteoarthritis, and obstructive sleep apnea status. Data were analyzed from November to December 2019.

EXPOSURES

RYGB or SG.

MAIN OUTCOMES AND MEASURES

The primary outcome measured in this study was the odds of fracture overall based on exposure to bariatric surgery. Secondary outcomes included the odds of type of fracture (humerus, radius or ulna, pelvis, hip, vertebrae, and total fractures) based on exposure to bariatric surgery.

RESULTS

A total of 49 113 patients were included and were equally made up of 16 371 bariatric surgery-eligible patients who did not undergo weight loss surgery, 16 371 patients who had undergone RYGB, and 16 371 patients who had undergone SG. Each group consisted of an equal number of 4109 men (25.1%) and 12 262 women (74.9%) and had an equal distribution of ages, with 11 780 patients (72.0%) 64 years or younger, 4230 (25.8%) aged 65 to 69 years, 346 (2.1%) aged 70 to 74 years, and 15 (0.1%) aged 75 to 79 years. Patients undergoing RYGB were found to have no significant difference in odds of fractures compared with bariatric surgery-eligible patients who did not undergo surgery. Patients undergoing undergone SG were found to have decreased odds of fractures of the humerus (odds ratio [OR], 0.57; 95% CI, 0.45-0.73), radius or ulna (OR, 0.38; 95% CI, 0.25-0.58), hip (OR, 0.49; 95% CI, 0.33-0.74), pelvis (OR, 0.34; 95% CI, 0.18-0.64), vertebrae (OR, 0.60; 95% CI, 0.48-0.74), or fractures in general (OR, 0.53; 95% CI, 0.46-0.62). Compared with patients undergoing SG, patients undergoing RYGB had a significantly greater risk of total fractures (OR, 1.79; 95% CI, 1.55-2.06) and humeral fractures (OR, 1.60; 95% CI, 1.24-2.07).

CONCLUSIONS AND RELEVANCE

In this cohort study, bariatric surgery was associated with a reduced risk of fracture in bariatric surgery-eligible patients. Sleeve gastrectomy might be the best option for weight loss in patients in which fractures could be a concern, as RYGB may be associated with an increased fracture risk compared with SG.

Beneficial impact of exercise on bone mass in individuals under calorie restriction: a systematic review and Meta-analysis of randomized clinical trials

Background: A major therapeutic goal in weight management should be total body fat reduction whereas as preserving lean body mass and bone mass density. It is uncertain if an exercise program reduces the adverse effects of calorie restriction-induced weight loss in adults.Objective: The aim of the present study was to evaluate the differences in bone mass between adults who enrolled in a calorie restriction or an exercise-calorie restriction induced weight loss program.Data sources: Both PubMed and Scopus libraries were searched up to February 2020.Methods: Systematic reviews and a meta-analysis were carried out of randomized clinical trials (published to February 2020) on differences in bone mineral density and content (BMD and BMC) of adults who lost weight by calorie restriction alone (CR) or exercise-calorie restriction (CR-E). The study quality was calculated using the Cochrane scoring system. Retrieved data were pooled when weight mean differences (WMDs) were computed between two groups for BMD and BMC at various sites of the body.Results: Thirteen studies, with a total of 852 participants were included. Available evidence found significantly higher BMD at the hip (WMD: 0.03 g/cm², 95%CI: 0.01 to 0.04, p < 0.001) and femoral neck WMD: 0.03 g/cm², 95%CI: 0.01 to 0.05, p < 0.001) and total body BMC (WMD: 0.13 kg/cm², 95%CI: -0.10 to 0.36, p < 0.001) in the CR-E compared to the CR weight loss group. In contrast, all changes in total body BMD (WMD: 0.00 g/cm², 95%CI: -0.01 to 0.02, p = 0.57) and lumbar spine BMD (WMD: 0.00 g/cm², 95%CI: -0.01 to 0.01, p = 0.89) were not statistically significant.Limitations: Little evidence was available for different sexes separately. Most individuals were postmenopausal females and no subgroup analysis could be conducted based on menopausal status.Conclusion: This study suggests that physical training can preserve and even significantly increase the bone mass of the hip and femoral neck during weight reduction. Of note, various exercise modalities affected BMD at different sites. Similar results were not found for lumbar spine and total body BMD.

Effect of Aerobic or Resistance Exercise, or Both, on Bone Mineral Density and Bone Metabolism in Obese Older Adults While Dieting: A Randomized Controlled Trial

Weight loss therapy of older adults with obesity is limited by weight loss-induced decrease in bone mineral density (BMD), which could exacerbate ongoing age-related bone loss and increase the risk for fractures. Therefore, it is recommended that weight loss therapy of older adults with obesity should include an intervention such as regular exercise to reduce the concomitant bone loss. However, the most appropriate exercise types to combine with weight loss therapy in this older population is unknown. In a randomized controlled trial, we performed a head-to-head comparison of aerobic or resistance exercise, or both, during matched ~10% weight loss in 160 older adults with obesity. We measured changes in BMD (total hip, femoral neck, trochanter, intertrochanter, one-third radius, lumbar spine) and bone markers. Changes between groups were analyzed using mixed-model repeated measures analyses of variance. After 6 months of intensive lifestyle interventions, BMD decreased less in the resistance group (-0.006 g/cm² [-0.7%]) and combination group (-0.012 g/cm² [-1.1%]) than in the aerobic group (-0.027 g/cm² [-2.6%]) (p = 0.001 for between-group comparisons). Serum C-telopeptide, procollagen type 1 N-propeptide, and osteocalcin concentrations increased more in the aerobic group (33%, 16%, and 16%, respectively) than in the resistance group (7%, 2%, and 0%, respectively) and combination group (11%, 2%, and 5%, respectively) (p = 0.004 to 0.048 for between-group comparisons). Multiple regression analyses revealed that the decline in whole body mass and serum leptin were the independent predictors of the decline in hip BMD (multiple R = 0.45 [p < .001]). These findings indicate that compared with aerobic exercise, resistance and combined aerobic and resistance exercise are associated with less weight loss-induced decrease in hip BMD and less weight loss-induced increase in bone turnover. Therefore, both resistance and combined aerobic and resistance exercise can be recommended to protect against bone loss during weight loss therapy of older adults with obesity. (LITOE ClinicalTrials.gov number NCT01065636.) © 2019 American Society for Bone and Mineral Research. Published 2019. This article is a U.S. Government work and is in the public domain in the USA.

Vitamin D, genetics, and bone mineral density during weight loss

PURPOSE OF REVIEW

The current review is to summarize the recent progress in the research of the relation between vitamin D and bone mineral density (BMD) during weight-loss interventions, and describe how genetic factors interact with weight-loss interventions on changes in bone health.

RECENT FINDINGS

Obesity has shown to be a protective factor for bone health, whereas the relation between weight loss and BMD has yet to be well established. Although beneficial on a variety of metabolic outcomes, weight-loss interventions, such as dietary modifications and surgical treatment, showed adverse effects on bone health in some studies. Despite the biological plausibility for a role of vitamin D in promoting bone health, current evidence does not consistently support the connection between changes in circulating vitamin D levels and BMD during weight loss, partly because of insufficient vitamin D levels during weight loss. Genome-wide association studies have identified genetic variants related to the blood levels of vitamin D; and emerging evidence suggests that dietary intakes may modify the relationship between genetically determined circulating vitamin D levels and change in BMD in response to weight-loss diets.

SUMMARY

The relations of changes in circulating vitamin D levels with bone health during weight-loss interventions remain to be established, and the role of genetic factors would be considered in future investigations.