Association of Visceral and Subcutaneous Fat Mass With Bone Density and Vertebral Fractures in Women With Severe Obesity

Associations between new obesity indices and abnormal bone density in type 2 diabetes mellitus patients

The clinical data analysis found that, compared with the traditional obesity index, the waist-weight ratio (WWR) has more advantages in predicting abnormal bone mineral density in subjects with type 2 diabetes. WWR may serve as a new predictive indicator for osteoporosis in T2DM patients.

PURPOSE

This study was designed to explore the correlation between obesity-related indices and bone mineral density (BMD) and its influencing factors in type 2 diabetes mellitus (T2DM) patients.

METHODS

A total of 528 patients with type 2 diabetes were recruited. Glucose tolerance, insulin stimulation, and blood biochemical tests were conducted on all participants. All subjects underwent dual-energy X-ray bone density testing and were grouped based on the bone density results.

RESULTS

Compared with those in the normal BMD group, the waist-to-body weight ratio (WWR) and weight-adjusted-waist index (WWI) in the osteopenia and osteoporosis groups were significantly greater, while body mass index (BMI) was significantly lower (P < 0.05). The logistic regression results showed that the WWR, WWI, and BMI were independently correlated with abnormal BMD in T2DM patients (P < 0.05). WWR and the WWI were negatively correlated with the T-value of bone density in various parts of the body, while BMI was positively correlated with the T-value of bone density (P < 0.05). The area under the working characteristic curve (AUC) for T2DM patients with abnormal bone mass predicted by the WWR [0.806, 95% CI = (0.770-0.843), P < 0.001] was greater than that for patients with other obesity indicators, such as the WWI and BMI.

CONCLUSION

We found a positive correlation between the WWR and bone density in T2DM patients. Compared with other obesity indicators, such as BMI and WWI, the WWR has a stronger discriminative ability for T2DM patients with abnormal bone density. Therefore, more attention should be given to the WWR in T2DM patients.

Links among Obesity, Type 2 Diabetes Mellitus, and Osteoporosis: Bone as a Target

Obesity, type 2 diabetes mellitus (T2DM) and osteoporosis are serious diseases with an ever-increasing incidence that quite often coexist, especially in the elderly. Individuals with obesity and T2DM have impaired bone quality and an elevated risk of fragility fractures, despite higher and/or unchanged bone mineral density (BMD). The effect of obesity on fracture risk is site-specific, with reduced risk for several fractures (e.g., hip, pelvis, and wrist) and increased risk for others (e.g., humerus, ankle, upper leg, elbow, vertebrae, and rib). Patients with T2DM have a greater risk of hip, upper leg, foot, humerus, and total fractures. A chronic pro-inflammatory state, increased risk of falls, secondary complications, and pharmacotherapy can contribute to the pathophysiology of aforementioned fractures. Bisphosphonates and denosumab significantly reduced the risk of vertebral fractures in patients with both obesity and T2DM. Teriparatide significantly lowered non-vertebral fracture risk in T2DM subjects. It is important to recognize elevated fracture risk and osteoporosis in obese and T2DM patients, as they are currently considered low risk and tend to be underdiagnosed and undertreated. The implementation of better diagnostic tools, including trabecular bone score, lumbar spine BMD/body mass index (BMI) ratio, and microRNAs to predict bone fragility, could improve fracture prevention in this patient group.

The effect of overweight or obesity on osteoporosis: A systematic review and meta-analysis

BACKGROUND

Osteoporosis and obesity are closely related, and the relationships between different types of obesity and osteoporosis are inconsistent.

OBJECTIVE

Our objective was to summarize earlier data concerning the association between osteoporosis and obesity (general and central), and to compare the impacts of these two obesity indicators on osteoporosis.

METHODS

From inception to May 2021, a comprehensive search in electronic bibliographic databases was conducted, and the search was updated in December 2021, July 2022 and June 2023. The data were independently extracted and evaluated by two investigators from epidemiological studies that reported the impact of obesity on the odds of incident osteoporosis.

RESULTS

There were 24 studies included in the final analysis when it came to general obesity measured by body mass index (BMI). Individuals with overweight and obesity had decreased odds of osteoporosis (odds ratio (OR), 0.451, 95% confidence intervals (CIs): 0.366-0.557). Sensitivity analyses showed that both overweight and obesity were decreased odds of osteoporosis, with reductions of 48.6% and 70.1%, respectively (OR, 0.514, 95% CI: 0.407-0.649; OR, 0.299, 95% CI: 0.207-0.433). Conversely, individuals classified as underweight were found to have higher odds of osteoporosis (OR, 2.540, 95% CI: 1.483-4.350). In term of central obesity, the final analysis consisted of 7 studies. No significant association was observed between central obesity and osteoporosis (OR, 0.913, 95% CI: 0.761-1.096).

CONCLUSIONS

General overweight and obesity were associated with lower odds of developing osteoporosis, whereas underweight was associated with higher odds. However, central obesity did not show a significant association with osteoporosis. These findings underscore the importance of considering the impact of obesity on osteoporosis. Further research is necessary to reinforce the evidence and validate our findings.

Regulation of bone and fat balance by Fructus Ligustri Lucidi in ovariectomized mice

CONTEXT

Fructus Ligustri Lucidi (FLL), a commonly used herb of traditional Chinese medicine (TCM), is the fruit of Ligustrum lucidum Ait. (Oleaceae). The ethanol extract of FLL is a potential candidate for preventing and treating postmenopausal osteoporosis (PMOP) by nourishing the liver and kidneys.

OBJECTIVE

This study determines whether an ethanol extract of FLL has anti-osteoporotic effects in ovariectomized (OVX) mice and explores the underlying mechanism.

MATERIALS AND METHODS

The OVX model of eight-week-old C57BL/6J female mice was taken, and ovariectomy was used as PMOP. Mice were divided into five groups: sham-operated group (n = 10), OVX group (n = 10), OVX + E₂ group (n = 10; 0.039 mg/kg), OVX + FLL group (n = 10; 2 g/kg) and OVX + FLL group (n = 10; 4 g/kg). Mice were treated by gavage with FLL or CMCNa once daily for 8 weeks. We harvested uteri, femur, and tibias from mice; bone mineral density (BMD) and bone microstructure were obtained by X-ray absorptiometry and micro-CT. Furthermore, the effect of FLL on the balance of osteoblast and adipocyte differentiation was investigated using bone marrow mesenchymal stem cells (BMMSCs).

RESULTS

The results indicated that FLL did not affect OVX-induced estradiol reduction. Compared with OVX mice, FLL significantly increased BMD (63.54 vs. 61.96), Conn. D (86.46 vs. 57.00), and left tibial strength (13.91 vs. 11.27), decreased Tb. Sp (0.38 vs. 0.44) and body fat content (4.19% vs. 11.24%). FLL decreased osteoclast activity and enhanced RUNX2 expression; inhibited perilipin peroxisome proliferator-activated receptor gamma (PPARγ) expression and adipocyte differentiation from BMMSCs.

CONCLUSIONS

FLL prevented additional bone loss and improved bone microstructure in OVX mice by modulating bone and fat balance, suggesting that FLL might be a therapeutic agent for PMOP.

The relationship between weight-adjusted-waist index and total bone mineral density in adults aged 20-59

Introduction

According to reports, obesity has a significant impact on bone health. And the weight-adjusted-waist index (WWI), superior to BMI and waist circumference (WC), is a new obesity indicator arising in recent years. This research investigated the relationship between WWI and total bone mineral density (BMD) for adults aged 20 to 59.

Methods

Using data from the 2011-2018 NHANES, we looked into the independent link between WWI and total BMD as well as its nonlinearity using weighted multiple linear regression and smooth curve fitting. Two-stage linear regression models were employed to calculate the threshold effects. There were additional subgroup analyses and testing for interactions.

Results

Multiple linear regression studies on a total of 10,372 individuals showed a significant inverse link between WWI and total BMD in adults between 20 and 59 [β = -0.04, 95% CI: (-0.04, -0.03), P<0.0001]. And smoking, race, and chronic kidney disease (CKD) had no significant effect on this negative connection (P for interaction >0.05). In addition, we found a nonlinear relationship between WWI and total BMD in diabetic and CKD patients, for which the saturation point was 11.38 cm/√kg in the CKD patient group and 10.29 cm/√kg in the diabetic patient group.

Conclusion

Our analysis demonstrated a significant inverse association between WWI and total BMD in adults aged 20-59.

Association of the visceral adiposity index with femur bone mineral density and osteoporosis among the U.S. older adults from NHANES 2005-2020: a cross-sectional study

Background

The visceral adiposity index (VAI) is a marker of abdominal fat distribution and adipose tissue function. However, the association between VAI and femur bone mineral density (BMD) and osteoporosis is unclear among the U.S. older adults.

Methods

Cross-sectional data for adults aged 60 years and older from the 2007-2020 National Health and Nutrition Examination Survey (NHANES) were included. Multivariable linear and logistic regression were used to evaluate the association between VAI and femur BMD and osteoporosis. We used the smooth curve fitting to address nonlinearity. Moreover, a two-piecewise linear regression model was used to explain the nonlinearity further.

Results

The findings of the multivariable logistic regression models showed that as the VAI value increased by one unit, the prevalence of osteoporosis decreased by 1.2% after adjusting for covariates associated with osteoporosis. The multivariable linear regression models demonstrated that VAI was positively correlated with femur BMD. Further analysis revealed an inverted L-shaped and inverted U-shaped relationship between VAI and femur BMD at different sites.

Conclusions

Our findings indicated that an increased VAI is independently linked to a higher prevalence of osteoporosis among the U.S. older adults. Further analysis reveals that once VAI reaches a certain threshold, femur BMD no longer increases and may even decrease. This suggests that a moderate accumulation of visceral fat may be beneficial for bone health, while excessive visceral fat could potentially have detrimental effects.

Gender-specific associations between abdominal adipose mass and bone mineral density in the middle-aged US population

OBJECTIVES

The relationship between abdominal adipose tissue and osteoporosis is poorly understood. The purpose of this study was to examine the associations of abdominal adipose tissue with bone mineral density (BMD) among a nationally representative sample of US middle-aged adults.

MATERIAL AND METHODS

This study included 1498 participants from the National Health and Nutrition Examination Survey 2013-2014 and 2017-2018. Dual-energy x-ray absorptiometry was used to measure BMD at the lumbar spine and femoral neck, as well as to assess abdominal adipose mass by categorizing total adipose tissue (TAT) into visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). Linear regression was used to assess the relationship between abdominal adipose tissue and BMD, and logistic regression and generalized additive model were used to assess the associations of abdominal adipose tissue with the development of low BMD.

RESULTS

In our study, men accounted for 51.3%, and the mean age and body mass index for men and women were 49.3 and 49.6 years, and 23.9 and 28.3 kg/m2, respectively. In the univariate model, we found that abdominal adipose mass was positively associated with BMD at femoral neck and spine in both genders. In the multivariate model, among men, a negative correlation was observed between TAT and SAT and BMD at the femoral neck. Additionally, higher masses of TAT, SAT, and VAT were found to significantly increase the risk of low BMD at both the femoral neck and lumbar spine. In contrast, there was no significant association between abdominal adipose mass and BMD in middle-aged women, regardless of menopausal status.

CONCLUSIONS

Our finding suggested that abdominal adipose tissue, regardless of its location (SAT or VAT), may have a negative impact on BMD in middle-aged men independently of body weight, but this relationship was not observed in women. Further research is needed to confirm these findings and investigate potential mechanisms underlying these associations.

Association of visceral and subcutaneous fat with bone mineral density in US adults: a cross-sectional study

The relationship between the accumulation of fat in visceral or subcutaneous tissue and bone mineral density (BMD) remains unclear. Our primary objective in this study was to illuminate this relationship by conducting an investigation on a vast scale, encompassing a nationally representative population in the United States. A weighted multiple linear regression model was established to evaluate the relationship between visceral fat, subcutaneous fat, and BMD. Additionally, the exploration of the potential nonlinear relationship was conducted employing the methodology of smooth curve fitting. In order to determine potential inflection points, a two-stage linear regression model was utilized. A total of 10,455 participants between the ages of 20 and 59 were included in this study. Various weighted multiple linear regression models revealed a negative correlation between lumbar BMD and visceral mass index (VMI) and subcutaneous mass index (SMI). However, the association between VMI and lumbar BMD displayed a U-shaped pattern upon employing the smooth curve fitting, and the inflection point of 0.304 kg/m2was determined using a two-stage linear regression model. Our findings indicated a negative association between subcutaneous fat and BMD. A U-shaped relationship was observed between visceral fat and BMD.

Association between androgen receptor gene alteration and osteoporosis in Chinese Han elderly men

Objective

To explore the role of blood glucose, blood lipids, and androgen receptor gene (CAG)n genotype in the pathogenesis of osteoporosis in Chinese Han men and to provide theoretical value for screening people susceptible to osteoporosis.

Methods

Patients who visited the First Affiliated Hospital of Chengdu Medical College from February 2021 to October 2021 were selected as research subjects to measure bone density by double-energy X-ray, osteoporosis patients as osteoporosis group (40 patients), and non-osteoporosis patients as the control group (40 patients). The STR method detected the repeat times of the androgen receptor gene (CAG)n in the two groups. The repeat times ≤22 were the SS genotype, and >22 were the LL genotype. Meanwhile, the patient's age, body mass index (BMI), blood glucose, blood lipids, calcium, phosphorus, and alkaline phosphatase examined on day one after admission were collected, and the statistical analysis was performed using SPSS 26.0.

Results

The results of the univariate analysis showed that there was no significant difference in age, calcium, phosphorus, alkaline phosphatase, and glycosylated hemoglobin between the two groups (P > 0.05). There were significant differences in average blood glucose, total cholesterol, triglyceride, high-density lipoprotein, low-density lipoprotein, and genotype frequency (P < 0.05). The multivariate logistic regression analysis results showed significant differences in total cholesterol and genotype frequency between the two groups (P < 0.05).

Conclusion

Androgen receptor LL genotype and elevated total cholesterol may be the risk factors for osteoporosis in older men of Han nationality.

The Relationship between Bone Mineral Densitometry and Visceral Adiposity Index in Postmenopausal Women

OBJECTIVE

 It was aimed to compare visceral adiposity index (VAI) levels in patients with normal bone mineral density (BMD), osteopenia, and osteoporosis.

METHODS

 One hundred twenty postmenopausal women (40 with normal BMD, 40 with osteopenia, and 40 with osteoporosis) between the ages of 50 to 70 years were included in the study. For females, the VAI was calculated using the formula (waist circumference [WC]/[36.58 + (1.89 x body mass index (BMI))]) x (1.52/High-density lipoprotein [HDL]-cholesterol [mmol/L]) x (triglyceride [TG]/0.81 [mmol/L]).

RESULTS

 The time of menopause from the beginning was similar in all groups. Waist circumference was found to be higher in those with normal BMD than in the osteopenic and osteoporotic groups (p = 0.018 and p < 0.001, respectively), and it was also higher in the osteopenic group than in the osteoporotic group (p = 0.003). Height and body weight, BMI, blood pressure, insulin, glucose, HDL-cholesterol, and homeostasis model assessment-insulin resistance (HOMA-IR) levels were similar in all groups. Triglyceride levels were found to be higher in the normal BMD group, compared with the osteoporotic group (p = 0.005). The level of VAI was detected as higher in those with normal BMD, compared with the women with osteoporosis (p = 0.002). Additionally, the correlation analysis showed a positive correlation between dual-energy X-ray absorptiometry (DXA) spine T-scores, WC, VAI, and a negative correlation between DXA spine T-scores and age.

CONCLUSION

 In our study, we found higher VAI levels in those with normal BMD, compared with women with osteoporosis. We consider that further studies with a larger sample size will be beneficial in elucidating the entity.

Discordance in lumbar bone mineral density measurements by quantitative computed tomography and dual-energy X-ray absorptiometry in postmenopausal women: a prospective comparative study

BACKGROUND CONTEXT

Level-specific lumbar bone mineral density (BMD) evaluation of a single vertebral body can provide useful surgical planning and osteoporosis management information. Previous comparative studies have primarily focused on detecting spinal osteoporosis but not at specific levels.

PURPOSE

To compare the detection rate of lumbar osteoporosis between quantitative computed tomography (QCT) and dual-energy X-ray absorptiometry (DXA); to explore and analyze the distribution models of QCT-derived BMD and DXA T-score at the specific levels; and to evaluate the diagnostic accuracy of level-specific BMD thresholds for the prediction of osteoporotic vertebral compression fracture (OVCF) in postmenopausal women.

STUDY DESIGN/SETTING

A comparative analysis of prospectively collected data comparing QCT-derived BMD with DXA T-score.

PATIENT SAMPLE

A total of 296 postmenopausal women who were referred to the spine service of a single academic institution were enrolled.

OUTCOME MEASURES

QCT-derived BMD and DXA T-score at specific levels, with or without osteoporotic vertebral compression fracture.

METHODS

Postmenopausal women who underwent QCT and DXA within a week of admission from May 2019 to June 2022 were enrolled. The diagnostic criteria for osteoporosis recommended by the World Health Organization and the American College of Radiology were used for lumbar osteoporotic diagnosis. To evaluate differences in lumbar BMD measurements at specific levels, a threshold of T score=-2.5 and QCT-derived BMD = 80 mg/cm³ were used to categorize level-specific lumbar BMD into low and high BMD. Disagreements in BMD categorization between DXA and QCT were classified as a minor or major discordance based on the definition by Woodson. Data between QCT and DXA were visualized in a stacked bar plot and analyzed. Correlations between DXA and QCT at the specific levels were evaluated using Pearson's linear correlation and scatter plots. Curve fitting of BMD distribution, receiver operating characteristic (ROC) and area under the curve (AUC) for each single vertebral level was performed.

RESULTS

Of the 296 patients, QCT diagnosed 61.1% as osteoporosis, 30.4% as osteopenia and 8.4% as normal. For those screened with DXA, 54.1% of the patients had osteoporosis, 29.4% had osteopenia and 16.6% had normal BMD. Diagnoses were concordant for 194 (65.5%) patients. Of the other 102 discordant patients, 5 (1.7%) were major and 97 (32.8%) were minor. Significant correlations in level-specific BMD between DXA and QCT were observed (p<.001), with Pearson's correlation coefficients ranging from 0.662 to 0.728. The correlation strength was in the order of L1 > L2 > L3 > L4. The low BMD detection rate for QCT was significantly higher than that for DXA at the L3 and L4 levels (65% vs. 47.9% and 68.1% vs 43.7, respectively, p<.001). Patients with OVCF showed significantly lower QCT-derived BMD (47.2 mg/cm³ vs. 83.2 mg/cm³, p<.001) and T-score (-3.39 vs. -1.98, p<.001) than those without OVCF. Among these patients, 82.8% (101/122) were diagnosed with osteoporosis by QCT measurement, while only 74.6% (91/122) were diagnosed by DXA. For discrimination between patients with and without OVCF, QCT-derived BMD showed better diagnosed performance (AUC range from 0.769 to 0.801) than DXA T-score (AUC range from 0.696 to 0.753).

CONCLUSION

QCT provided a more accurate evaluation of lumbar osteoporosis than DXA. The QCT-derived BMD measurements at a specific lumbar level have a high diagnostic performance for OVCF.

Bone mineral density and lipid profiles in older adults: a nationwide cross-sectional study

It has been hypothesized that lipid profiles are associated with bone mineral density (BMD), but previous results have been controversial. In this study, serum triglycerides showed a significant inverse association with BMD, and the relationship is thought to correlate with vitamin D status among older adults.

INTRODUCTION

The purpose of this study was to investigate the relationship between lipid profiles and bone mineral density (BMD) in older adults using data from the Korean National Health and Nutrition Examination Survey (KNHANES).

METHODS

We enrolled men older than 50 years and postmenopausal women who participated in the KNHANES 2008-2011. Subjects with liver cirrhosis, thyroid disease, or renal dysfunction and those receiving treatment for hyperlipidemia or osteoporosis were excluded.

RESULTS

A total of 4323 subjects (2286 men and 2037 women) was analyzed. The prevalence of osteoporosis was 8.7% in men older than 50 years and 38.4% in postmenopausal women. Osteopenia and osteoporosis groups were generally older and tended to have a lower body mass index compared to the normal group (p for trend < 0.001). The correlation between each lipid profile and BMD was analyzed in the linear model adjusted for age and body mass index. Total cholesterol and high-density lipoprotein cholesterol showed a negative correlation with BMD in the total population, but there was no significant correlation when analyzed separately for men and women. Triglycerides had a negative association with whole-body BMD in both men and women (p < 0.05). The adjusted odds ratio of logarithmic triglyceride level for osteoporosis was 2.50 (95% confidence interval 1.13-5.51) in women older than 65 years.

CONCLUSION

Serum triglycerides showed a significant inverse association with BMD, and the relationship is thought to correlate with vitamin D status among older adults.

Quantification of lumbar vertebral fat deposition: Correlation with menopausal status, non-alcoholic fatty liver disease and subcutaneous adipose tissue

PURPOSE

To assess abdominal fat deposition and lumbar vertebra with iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ) and investigate their correlation with menopausal status.

MATERIALS AND METHODS

Two hundred forty women who underwent routine abdominal MRI and IDEAL-IQ between January 2016 and April 2021 were divided into two cohorts (first cohort: 120 pre- or postmenopausal women with severe fatty livers or without fatty livers; second cohort: 120 pre- or postmenopausal women who were obese or normal weight). The fat fraction (FF) values of the liver (FF_liver) and lumbar vertebra (FF_lumbar) in the first group and the FF values of subcutaneous adipose tissue (SAT) (FF_SAT) and FF_lumbar in the second group were measured and compared using IDEAL-IQ.

RESULTS

Two hundred forty women were evaluated. FF_lumbar was significantly higher in both pre- and postmenopausal women with severe fatty liver than in patients without fatty livers (premenopausal women: p < 0.001, postmenopausal women: p < 0.001). No significant difference in the FF_lumbar was observed between obese patients and normal-weight patients among pre- and postmenopausal women (premenopausal women: p = 0.113, postmenopausal women: p = 0.092). Significantly greater lumbar fat deposition was observed in postmenopausal women than in premenopausal women with or without fatty liver and obesity (p < 0.001 for each group). A high correlation was detected between FF_liver and FF_lumbar in women with severe fatty liver (premenopausal women: r=0.76, p<0.01; postmenopausal women: r=0.82, p<0.01).

CONCLUSION

Fat deposition in the vertebral marrow was significantly associated with liver fat deposition in postmenopausal women.