The effects of weight loss on relative bone mineral density in premenopausal women

The Effect of a Very-Low-Calorie Diet (VLCD) vs. a Moderate Energy Deficit Diet in Obese Women with Polycystic Ovary Syndrome (PCOS)-A Randomised Controlled Trial

We performed an open-label, randomised controlled trial to compare the effects of a very-low-calorie diet (VLCD) vs. moderate energy deficit approach on body weight, body composition, free androgen index (FAI), and metabolic markers in obese women with polycystic ovary syndrome (PCOS). Forty eligible patients were randomly assigned to a VLCD (n = 21) or a conventional energy deficit approach (n = 19) over the same period. After eight weeks, both groups experienced significant weight loss; however, this was greater in the VLCD arm (-10.9% vs. -3.9%, p < 0.0001). There was also a trend towards a reduction in FAI in the VLCD group compared to the energy deficit group (-32.3% vs. -7.7%, p = 0.07). In the VLCD arm, two women (18%) had a biochemical remission of PCOS (FAI < 4); this was not the case for any of the participants in the energy deficit arm. There was a significant within-group increase in the sex-hormone-binding globulin (p = 0.002) and reductions in fasting blood glucose (p = 0.010) and waist to hip ratio (p = 0.04) in the VLCD arm, but not in the energy deficit arm. The VLCD resulted in significantly greater weight reduction and was accompanied by more pronounced improvements in hyperandrogenaemia, body composition, and several metabolic parameters in obese women with PCOS as compared to the energy deficit approach.

The Effect of Caloric Restriction with and without n-3 PUFA Supplementation on Bone Turnover Markers in Blood of Subjects with Abdominal Obesity: A Randomized Placebo-Controlled Trial

Weight loss contributes to an increased risk of hip fracture, especially in postmenopausal women. Omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation could diminish the adverse effect of weight loss on bone health. The aim of this randomized, placebo-controlled, double-blind parallel trial was to investigate the effect of caloric restriction and n-3 PUFA supplement intake on osteogenic markers (carboxylated osteocalcin (Gla-OC); procollagen I N-terminal propeptide (PINP)), as well as a bone resorption marker (C-terminal telopeptide of type I collagen (CTX-I)) in a serum of 64 middle aged individuals (BMI 25-40 kg/m²) with abdominal obesity. Bone remodeling, metabolic and inflammatory parameters and adipokines were determined before and after 3 months of an isocaloric diet (2300-2400 kcal/day) or a low-calorie diet (1200 kcal/day for women and 1500 kcal/day for men) along with n-3 PUFA (1.8 g/day) or placebo capsules. CTX-I and adiponectin concentrations were increased following 7% weight loss independently of supplement use. Changes in CTX-I were positively associated with changes in adiponectin level (rho = 0.25, p = 0.043). Thus, an increase in serum adiponectin caused by body weight loss could adversely affect bone health. N-3 PUFAs were without effect.

Comparisons of patellar bone mineral density between individuals with and without patellofemoral pain

BACKGROUND

Although bone stress injuries have been reported in individuals with patellofemoral pain (PFP), especially within the lateral patella, it remains unclear whether persons with PFP exhibit altered patellar regional bone mineral density (BMD). The primary purpose of this study was to compare BMD of the patella (lateral, medial, and total regions) between individuals with and without PFP using quantitative computed tomography (QCT). The secondary aim was to examine the associations between patellar regional BMD and patellofemoral joint (PFJ) alignment.

METHODS

Ten individuals with retropatellar pain and 10 sex, age, weight, height, and activity matched pain-free controls underwent a QCT scan to obtain patellar BMD. To quantify PFJ alignment, patellar lateral displacement was measured using bisect-offset (BSO) index and patellar mediolateral tilt was quantified using patellar tilt angle (PTA). A two-factor repeated-measures ANOVA was used to compare BMD across the three patellar regions and between the two groups. Pearson correlation coefficient analyses were used to evaluate the associations between BMD and PFJ alignment of all participants.

RESULTS

There was no difference in BMD between the two groups. However, BMD was highest within the lateral patella and was lowest within the medial patella across both groups. There were significantly moderate to large correlations between BSO index/PTA and BMD within lateral, medial, and total regions.

CONCLUSIONS

While individuals with PFP and pain-free controls have similar patellar BMD, the lateral patella exhibits the highest BMD. Additionally, higher patellar regional BMD is related to increased patellar lateral displacement and lateral tilt.

Weight loss and bone mineral density in obese adults: a longitudinal analysis of the influence of very low energy diets

Background

The long-term effect of weight reduction on skeletal health is not well understood. The purpose of this study was to examine the impact of an intensive medical weight loss intervention using very low energy diet (VLED) (~ 800 cal/day) that result in significant changes in body weight, on total body bone mineral density (BMD) over 2 years.

Methods

We examined the impact of VLED-induced weight loss on BMD and FFM (Fat-free Mass) after 3–6 months and again while in weight maintenance at 2 years in 49 subjects. The effects of absolute and relative rate of weight reduction assessed by change in weight in kilograms were assessed using general linear modeling, with baseline BMD (or FFM) as a covariate, and age, sex and changes in body weight as primary model predictors.

Results

At the end of 2 years, the average weight loss was greater for men (weight: 23.51 ± 12.5 kg) than women (weight: 16.8 ± 19.2 kg) and BMD loss was greater among women (0.03 ± 0.04 g/cm² vs 0.01 ± 0.04 g/cm²) (all p < 0.05). After adjusting for baseline BMD, age, and sex, there was a small but significant association between total weight loss and 2-year BMD (β = − 0.001 g/cm²; p = 0.01). Similarly, there was a significant independent association between total weight loss and 2-year FFM (β = − 116.5 g; p < 0.01).

Conclusions

Despite significant weight loss with VLED, there was only a small loss is BMD.

Utility of DXA for monitoring, technical aspects of DXA BMD measurement and precision testing

Monitoring a patient's bone mineral density (BMD) is one of the main reasons for dual-energy X-ray absorptiometry (DXA) referral. It is widely recommended by clinical guidelines, and the accepted standard in practice for managing patients with osteoporosis and other disorders. Clinicians and DXA providers must be familiar with the scientific rationale and procedures involved in measurement science to obtain accurate and reproducible results. Their importance is critical to maximise the value of scan acquisition and interpretation. Scanning individual patients, with different needs and disorders, requires excellence in training, experience, and is more complex than just simply 'measuring BMD'. Over the past 3 decades many studies have validated the importance of monitoring BMD for fracture risk assessment, and for patients on osteoporosis treatment. New DXA features enhance the value of DXA monitoring today. Quality BMD measurement remains an essential component of patient care in osteoporosis and other disorders, playing a critical role in informed decision making for clinicians assessing and managing their patients. In this article we describe some of the technical aspects of measurement and discuss the utility of DXA for monitoring patients in clinical practice.

The effects of weight loss approaches on bone mineral density in adults: a systematic review and meta-analysis of randomized controlled trials

We assessed the impact of weight loss strategies including calorie restriction and exercise training on BMD in adults using a systematic review of randomized controlled trials. Weight reduction results in reduced BMD at the hip, but has less effect on the spine. Both calorie restriction and a combination of calorie restriction and exercise result in a decrease in hip bone density, whereas weight loss response to exercise training without dietary restriction leads to increased hip BMD.

INTRODUCTION

Findings are not consistent on the effect of weight loss on bone mineral density (BMD). We conducted a systematic review on the randomized controlled trials to assess the effect of weight loss strategies, including calorie restriction and exercise programs on BMD in adults.

METHODS

A structured and comprehensive search of MEDLINE and EMBASE databases was undertaken up to March 2016. Study-specific mean differences (MD) were pooled using a random-effects model. Subgroup analysis and meta-regression were used to find possible sources of between-study heterogeneity.

RESULTS

Thirty-two randomized controlled trials met predetermined inclusion criteria. The meta-analysis revealed no significant difference on total BMD (MD 0.007, 95 % CI -0.020-0.034, p = 0.608). In contrast, the pooled data of studies showed a significant effect of weight loss on hip BMD (MD -0.008, 95 % CI -0.09 to -0.006 g/cm(2), p < 0.001) and also lumbar spine BMD (MD -0.018 g/cm(2), 95 % CI -0.019 to -0.017, p < 0.001). BMD in the hip site decreased after more than 4 months, especially in those who were obese. Moreover, calorie restriction interventions longer than 13 months showed a significant decreased in lumbar spine BMD.

CONCLUSION

Weight loss led to significant decreases at the hip and lumbar spine BMD but not at the total. Weight loss response following calorie restriction resulted in a decrease in hip and lumbar spine bone density especially more than 1 year; whereas an exercise-induced weight loss did not.

BMI and BMD: The Potential Interplay between Obesity and Bone Fragility

Recent evidence demonstrating an increased fracture risk among obese individuals suggests that adipose tissue may negatively impact bone health, challenging the traditional paradigm of fat mass playing a protective role towards bone health. White adipose tissue, far from being a mere energy depot, is a dynamic tissue actively implicated in metabolic reactions, and in fact secretes several hormones called adipokines and inflammatory factors that may in turn promote bone resorption. More specifically, Visceral Adipose Tissue (VAT) may potentially prove detrimental. It is widely acknowledged that obesity is positively associated to many chronic disorders such as metabolic syndrome, dyslipidemia and type 2 diabetes, conditions that could themselves affect bone health. Although aging is largely known to decrease bone strength, little is yet known on the mechanisms via which obesity and its comorbidities may contribute to such damage. Given the exponentially growing obesity rate in recent years and the increased life expectancy of western countries it appears of utmost importance to timely focus on this topic.

Does Diet-Induced Weight Loss Lead to Bone Loss in Overweight or Obese Adults? A Systematic Review and Meta-Analysis of Clinical Trials

Diet-induced weight loss has been suggested to be harmful to bone health. We conducted a systematic review and meta-analysis (using a random-effects model) to quantify the effect of diet-induced weight loss on bone. We included 41 publications involving overweight or obese but otherwise healthy adults who followed a dietary weight-loss intervention. The primary outcomes examined were changes from baseline in total hip, lumbar spine, and total body bone mineral density (BMD), as assessed by dual-energy X-ray absorptiometry (DXA). Secondary outcomes were markers of bone turnover. Diet-induced weight loss was associated with significant decreases of 0.010 to 0.015 g/cm(2) in total hip BMD for interventions of 6, 12, or 24 (but not 3) months' duration (95% confidence intervals [CIs], -0.014 to -0.005, -0.021 to -0.008, and -0.024 to -0.000 g/cm(2), at 6, 12, and 24 months, respectively). There was, however, no statistically significant effect of diet-induced weight loss on lumbar spine or whole-body BMD for interventions of 3 to 24 months' duration, except for a significant decrease in total body BMD (-0.011 g/cm(2); 95% CI, -0.018 to -0.003 g/cm(2)) after 6 months. Although no statistically significant changes occurred in serum concentrations of N-terminal propeptide of type I procollagen (P1NP), interventions of 2 or 3 months in duration (but not of 6, 12, or 24 months' duration) induced significant increases in serum concentrations of osteocalcin (0.26 nmol/L; 95% CI, 0.13 to 0.39 nmol/L), C-terminal telopeptide of type I collagen (CTX) (4.72 nmol/L; 95% CI, 2.12 to 7.30 nmol/L) or N-terminal telopeptide of type I collagen (NTX) (3.70 nmol/L; 95% CI, 0.90 to 6.50 nmol/L bone collagen equivalents [BCEs]), indicating an early effect of diet-induced weight loss to promote bone breakdown. These data show that in overweight and obese individuals, a single diet-induced weight-loss intervention induces a small decrease in total hip BMD, but not lumbar spine BMD. This decrease is small in comparison to known metabolic benefits of losing excess weight.

Multilevel Approach of a 1-Year Program of Dietary and Exercise Interventions on Bone Mineral Content and Density in Metabolic Syndrome--the RESOLVE Randomized Controlled Trial

Background

Weight loss is a public health concern in obesity-related diseases such as metabolic syndrome (MetS). However, restrictive diets might induce bone loss. The nature of exercise and whether exercise with weight loss programs can protect against potential bone mass deficits remains unclear. Moreover, compliance is essential in intervention programs. Thus, we aimed to investigate the effects that modality and exercise compliance have on bone mineral content (BMC) and density (BMD).

Methods

We investigated 90 individuals with MetS who were recruited for the 1-year RESOLVE trial. Community-dwelling seniors with MetS were randomly assigned into three different modalities of exercise (intensive resistance, intensive endurance, moderate mixed) combined with a restrictive diet. They were compared to 44 healthy controls who did not undergo the intervention.

Results

This intensive lifestyle intervention (15–20 hours of training/week + restrictive diet) resulted in weight loss, body composition changes and health improvements. Baseline BMC and BMD for total body, lumbar spine and femoral neck did not differ between MetS groups and between MetS and controls. Despite changes over time, BMC or BMD did not differ between the three modalities of exercise and when compared with the controls. However, independent of exercise modality, compliant participants increased their BMC and BMD compared with their less compliant peers. Decreases in total body lean mass and negative energy balance significantly and independently contributed to decreases in lumbar spine BMC.

Conclusion

After the one year intervention, differences relating to exercise modalities were not evident. However, compliance with an intensive exercise program resulted in a significantly higher bone mass during energy restriction than non-compliance. Exercise is therefore beneficial to bone in the context of a weight loss program.

Trial Registration

ClinicalTrials.gov NCT00917917

Sex Differences in the Effects of Weight Loss Diets on Bone Mineral Density and Body Composition: POUNDS LOST Trial

CONTEXT

Weight loss is associated with reduction in bone mineral density (BMD).

OBJECTIVE

The objective was to address the role of changes in fat mass (FM) and lean mass (LM) in BMD decline in both sexes.

DESIGN

A 2-year randomized controlled trial, the Preventing Overweight Using Novel Dietary Strategies (POUNDS-LOST).

SETTING

The setting was the general community.

PATIENTS OR OTHER PARTICIPANTS

Enrolled were 424 overweight and obese participants (mean age, 52 ± 9 y; 57% females).

INTERVENTION

Intervention included weight loss diets differing in fat, protein, and carbohydrates.

MAIN OUTCOME MEASURES

Main outcome measures were change in spine, total hip (TH), and femoral neck (FN) BMD and sex differences after dietary intervention.

RESULTS

At baseline, a stronger correlation between BMD and body composition measurements was observed in women, primarily with LM (r = 0.419, 0.507, and 0.523 for spine, FN, and TH, respectively; all P < .001). In men, only LM correlated with hip BMD (r = 0.298; P < .001). Mean weight loss at 2 years was -6.9%, without differences among diets. Two-year changes in BMD were 0.005 (P = .04), -0.014 (P < .001), and -0.014 g/cm(2) (P < .001), at the spine, TH, and FN, respectively. These changes directly correlated with changes in LM in women (r = 0.200, 0.324, and 0.260 for spine, FN, and TH, respectively), whereas FM loss correlated only with changes in TH BMD (0.274; P < .001). In men, changes in LM (-0.323; P < .001) and FM (-0.213; P = .027) negatively correlated with changes in spine BMD.

CONCLUSIONS

Weight loss diets result in sex-specific effects on BMD. Although men exhibited a paradoxical increase in spine BMD, women tended to decrease in BMD at all sites.

The neuropeptide Y-ergic system: potential therapeutic target against bone loss with obesity treatments

Obesity is no longer considered to provide protection against osteoporosis. Moreover, treatments for obesity are now suspected of reducing bone mass. With the escalating incidence of obesity, combined with increases in the frequency, duration and intensity of interventions used to combat it, we face a potential increase in health burden due to osteoporotic fractures. The neuropeptide Y-ergic system offers a potential target for the prevention and anabolic treatment of bone loss in obesity, due to its dual role in the regulation of energy homeostasis and bone mass. Although the strongest stimulation of bone mass by this system appears to occur via indirect hypothalamic pathways involving Y2 receptors (one of the five types of receptors for neuropeptide Y), Y1 receptors on osteoblasts (bone-forming cells) induce direct effects to enhance bone mass. This latter pathway may offer a suitable target for anti-osteoporotic treatment while also minimizing the risk of adverse side effects.

Weight loss and bone mineral density

PURPOSE OF REVIEW

Despite evidence that energy deficit produces multiple physiological and metabolic benefits, clinicians are often reluctant to prescribe weight loss in older individuals or those with low bone mineral density (BMD), fearing BMD will be decreased. Confusion exists concerning the effects that weight loss has on bone health.

RECENT FINDINGS

Bone density is more closely associated with lean mass than total body mass and fat mass. Although rapid or large weight loss is often associated with loss of bone density, slower or smaller weight loss is much less apt to adversely affect BMD, especially when it is accompanied with high intensity resistance and/or impact loading training. Maintenance of calcium and vitamin D intake seems to positively affect BMD during weight loss. Although dual energy X-ray absorptiometry is normally used to evaluate bone density, it may overestimate BMD loss following massive weight loss. Volumetric quantitative computed tomography may be more accurate for tracking bone density changes following large weight loss.

SUMMARY

Moderate weight loss does not necessarily compromise bone health, especially when exercise training is involved. Training strategies that include heavy resistance training and high impact loading that occur with jump training may be especially productive in maintaining, or even increasing bone density with weight loss.

Divergent effects of obesity on bone health

Historically, obesity was thought to be advantageous for maintaining healthy bones due to the greater bone mineral density observed in overweight individuals. However, recent observations of increased fracture in some obese individuals have led to concern that common metabolic complications of obesity, such as type 2 diabetes, metabolic syndrome, impaired glucose tolerance, insulin resistance, hyperglycemia, and inflammation may be associated with poor bone health. In support of this hypothesis, greater visceral fat, a hallmark of insulin resistance and metabolic syndrome, is associated with lower bone mineral density. Research is needed to determine if and how visceral fat and/or poor metabolic health are causally associated with bone health. Clinicians should consider adding a marker metabolic health, such as waist circumference or fasting plasma glucose concentration, to other known risk factors for osteoporosis and fracture.