Fat mass is negatively associated with bone mineral content in Koreans

Correlation between Body Composition and Bone Mineral Density Differs by Sex and Skeletal Site in Overweight and Obese Chinese Subjects

Previous studies have yielded inconsistent results regarding the relationship between obesity and bone mineral density (BMD). The aim of this study was to determine the influence of body composition on BMD and the serum sclerostin level in overweight and obese adults. The study had a cross-sectional design and included 90 men and 118 women with a body mass index ≥25. Fat mass, lean mass, and spinal and pelvic BMD were measured using dual-emission X-ray absorptiometry. Subcutaneous fat, visceral fat, and lean mass were measured between L2 and L3 by 16-slice spiral computed tomography. The serum sclerostin level was determined by enzyme-linked immunosorbent assay. Pearson analysis showed that fat mass and appendicular lean mass were positively correlated with spinal BMD in both sexes. A positive association of both fat mass and lean mass with pelvic BMD, which was stronger in women, was also found. Partial correlation analysis showed the positive association between fat mass and BMD was significantly attenuated but the positive association between lean mass and pelvic BMD remained after adjustment for age and body weight. A negative correlation was observed between visceral fat and spinal and pelvic BMD only in women, and the positive association between lean mass with pelvic BMD was more obvious in women than in men, indicating body composition seemed to have a greater impact on the BMD in women. The serum sclerostin level was positively associated with BMD but not with body composition. These findings suggest that the correlation between body composition and BMD is influenced by sex and skeletal site.

Linking Non-alcoholic Fatty Liver Disease Severity With Metabolic Syndrome Features: An Integrative Study on Clinical and Radiological Fronts

Introduction Non-alcoholic fatty liver disease (NAFLD) has become a widespread cause of chronic liver disease, ranging from simple steatosis to severe conditions like non-alcoholic steatohepatitis (NASH) and cirrhosis. Despite its similarity to alcohol-induced liver damage, NAFLD affects individuals with no significant alcohol consumption. This study explores the association between NAFLD, bone mineral density (BMD), insulin resistance, and subclinical inflammation, focusing on the Asian Indian population. The primary objective was to investigate the relationship between NAFLD and BMD, insulin levels, and markers of subclinical inflammation, hypothesizing that patients with NAFLD exhibit lower BMD, possibly linked to insulin resistance and inflammation. Methodology A cross-sectional study with 100 subjects aged 18-50 years (50 cases with NAFLD and 50 controls) was conducted. Exclusion criteria included excessive alcohol consumption, drug-induced fatty liver, severe organ dysfunction, infections, pregnancy, and acute or chronic illness. Data were collected through clinical examinations, anthropometric measurements, biochemical investigations, ultrasound diagnosis of NAFLD, and dual-energy X-ray absorptiometry (DEXA) scans for BMD assessment. Statistical analysis employed the chi-squared tests, t-tests, and Wilcoxon rank-sum tests. Results NAFLD patients had higher body mass index (BMI), waist-to-hip ratio, and markers of insulin resistance and inflammation compared to non-NAFLD controls. DEXA scans revealed significantly lower BMD in NAFLD cases, along with a higher prevalence of osteopenia. Positive correlations were observed between BMD and insulin resistance. The study contributes to understanding the link between NAFLD and lower BMD in the Asian Indian population, emphasizing the impact of insulin resistance and inflammation on bone health. The literature review supports the relevance of exploring NAFLD as an independent risk factor for low BMD. Conclusion This case-control study underscores the significant association between NAFLD and lower BMD in the Asian Indian population. Despite limitations, the findings highlight the importance of further research with larger samples and comprehensive assessments to elucidate the interplay between NAFLD, metabolic factors, and bone health.

The effect of a body shape index (ABSI) and its interaction with low estimated glomerular filtration rate (eGFR) on osteoporosis in elderly Chinese

BACKGROUND

Both obesity and chronic kidney disease (CKD) contribute to osteoporosis risk, but the effect of a newly developed index (e.g., a body shape index, ABSI) of central obesity and its interaction with low estimated glomerular filtration rate (eGFR) on osteoporosis remains unknown.

METHODS

A total of 2534 Chinese individuals were enrolled in our ongoing cohort study: Osteoporosis Preventive Project. ABSI and eGFR were calculated as obesity-related indexes and renal function markers, respectively. A logistic regression model was used to estimate the association between osteoporosis and related clinical parameters (e.g., ABSI, eGFR), and to assess the additive and multiplicative interactions between risk factors and osteoporosis. Relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP) and synergy index (SI) were calculated to assess the additive interaction.

RESULTS

High ABSI was significantly associated with an increased risk of osteoporosis in participants compared with the lowest quartile of ABSI in both crude and adjusted models. Individuals in the lower quartiles of eGFR had a significantly increased risk of osteoporosis compared with those in the highest quartiles in crude models. After adding age and other variables in the model, the association was abolished. In addition, after adjusting for variables, high ABSI with low eGFR (RERI: 0.45, 95% CI: 0.15-0.75; AP: 0.39, 95% CI: 0.17-0.60) still displayed a noticeable interaction on the risk of osteoporosis. The multiplicative interactive effect between high ABSI with low eGFR on osteoporosis was statistically significant in the multivariable-adjusted model (P < 0.05).

CONCLUSION

Our study indicated that higher ABSI increases the risk of osteoporosis independently and synergistically with low eGFR in Chinese elderly adults. The findings increase our understanding of the interactions of osteoporosis risk factors and may help provide potential interventions for osteoporosis.

Comparison of clinical outcome of lumbar spinal stenosis surgery in patients with and without osteoporosis: a prospective cohort study

BACKGROUND

Osteoporosis is one of the most important risk factors for failure of the spine instrumentation. Management of patients with osteoporosis who requires spinal surgery because of the difficulty in instrument placement and the potential complications is still a challenge. This study was designed to evaluate the clinical outcome of lumbar spinal canal stenosis after instrumentation in patients with and without osteoporosis.

METHODS

This prospective cohort study was performed from June 2018 to December 2020, in Be'sat Hospital, Hamadan, Iran. The sample consisted of patients over 50 years old referred to Be'sat Hospital with a diagnosis of lumbar spinal canal stenosis who underwent instrumental surgery (n = 107). Based on bone densitometry, the sample was divided into two groups with osteoporosis (n = 34) and without osteoporosis (n = 73). To collect data, we used a three-part researcher-made questionnaire (demographic information, medical records information, and paraclinical parameters). Statistical analyzes were performed by the Fisher Exact, chi-square, independent t-test, Multiple ANCOVA, Mann-Whitney and the Rank Wilcoxson tests using Stata version 17 software.

RESULTS

The mean age (SD) of patients in the two groups with and without osteoporosis was 67.9 (7.0) and 59.1 (5.1) years, respectively (p = 0.001). The results indicated that a significant difference was observed between the two groups in sex (p = 0.032), educational status (p = 0.001), marital status (p = 0.023), employment status (p = 0.004), menopausal status (p = 0.018), taking corticosteroids (p = 0.028), and body mass index (p = 0.015). Also, there was a significant difference between two groups in the loosening of instrument (p = 0.039), the postoperative pain intensity (p = 0.007), fusion (p = 0.047), and neurogenic claudication (p = 0.003). Based on multiple ANCOVA test, there was not a significant difference between two groups in the clinical and paraclinical charatecristics (p > 0.05). The mean (SD) of T-Score in the osteoporosis group was 3.06 (0.37).

CONCLUSION

This study provides evidence that there is no significant difference in the clinical outcomes of lumbar spine instrumentation due to spinal canal stenosis in patients with and without osteoporosis. Because of the high cost of specific instrumentation developed for patients with osteoporosis and their unavailability, it seems that the use of conventional instrumentation along with complete treatment of osteoporosis can help improve the clinical outcome of surgery in these patients.

Association of insulin resistance with bone mineral density in a nationwide health check-up population in China

INTRODUCTION

Insulin resistance (IR) is closely associated with cardio-metabolic diseases. However, the impact of IR on bone mass remains obscure. The present study is to evaluate the association between the triglyceride-glucose (TyG) indicated IR and bone mass in a nationwide health check-up population in China.

METHODS

We conducted a retrospective cross-sectional study including 788,247 participants and a longitudinal cohort study in 8770 participants who had repeated measurements of TyG index and bone mass in at least a 2-year follow-up period. The restricted cubic splines and logistic models were used to analyze the association between IR and bone mass in the cross-sectional study. The Cox model was applied to evaluate the relationship between baseline IR and the subsequent incidence of low bone mass and osteoporosis in the longitudinal study.

RESULTS

In the cross-sectional study, the TyG index had positive correlations with low bone mass, osteoporosis, or both after adjusting for confounding factors (all P < 0.001). In the longitudinal cohort study, the baseline TyG index was significantly associated with the incidence of low bone mass, osteoporosis, or both during the follow-up period, with hazard ratios (HRs) of 1.56 (95 % confidence interval [CI]: 1.25, 1.93, P < 0.05), 1.66 (95%CI: 1.06, 2.59, P < 0.05), and 1.55 (95%CI: 1.27, 1.88, P < 0.05) after adjusting for confounding factors, respectively.

CONCLUSIONS

These results suggest that IR indicated by TyG is significantly associated with an increased risk of low bone mass and osteoporosis. Therefore, bone mass monitoring and early prevention strategies may be needed in individuals with IR to prevent the occurrence of low bone mass and osteoporosis.

The association between abdominal obesity and femoral neck bone mineral density in older adults

BACKGROUND

The relationship between obesity and osteoporosis is complex, with contradictory findings reported. Our aim was to evaluate the association between waist circumference (WC), as an easy-to-determine clinical index of abdominal obesity, and femoral neck bone mineral density (BMD) among older adults, using the National Health and Nutrition Examination Survey (NHANES) database.

METHODS

Data of five NHANES cycles (2005-2010, 2013-2014, and 2017-2018), including 5801 adults aged ≥ 60 years, were used in the analysis. Weighted multiple regression analyses were performed to evaluate the association between WC and femoral neck BMD. Weighted generalized additive models and smooth curve fitting were further performed to characterize nonlinearities in the association.

RESULTS

There was a positive association between WC and femoral neck BMD in non-adjusted models. After adjusting for body mass index (BMI), the association became negative. On subgroup analysis stratified by sex, this negative association only existed for men. An inverted U-shaped curve relationship between WC and femoral neck BMD was further identified, with an inflection point at a WC of 95 cm for both men and women.

CONCLUSIONS

Abdominal obesity is a negative predictor of bone health among older adults, independent of BMI. The association between WC and femoral neck BMD followed an inverted U-shaped curve.

Menopause-Related Changes in Body Composition Are Associated With Subsequent Bone Mineral Density and Fractures: Study of Women's Health Across the Nation

During the menopause transition (MT), lean mass decreases and fat mass increases. We examined the associations of these body composition changes during the MT (2 years before to 2 years after the final menstrual period) with bone mineral density (BMD) at the end of the MT and fracture after the MT. We included 539 participants from the Study of Women's Health Across the Nation who were not taking bone-beneficial or bone-detrimental medications before or during the MT. Using multivariable linear regression, we assessed the independent associations of % lean mass loss and % fat mass gain during the MT (mutually adjusted) with femoral neck (FN) and lumbar spine (LS) BMD at the end of the MT, adjusted for pre-MT BMD, pre-MT lean and fat mass, race/ethnicity, Study of Women's Health Across the Nation (SWAN) study site, age, and cigarette use. We used Cox proportional hazards regression to quantify the relations of % lean loss and % fat gain during the MT with fracture after the MT. The Cox model was adjusted for the covariates above plus post-MT use of bone-detrimental medications, and censored at the first use of bone-beneficial medications; we further controlled for FN or LS BMD at the end of the MT. Adjusted for covariates, each standard deviation (SD) (6.9%) increment in lean mass loss was associated with 0.010 g/cm2 lower FN BMD (p < 0.0001); each SD (19.9%) increment in fat mass gain was related to 0.026 g/cm2 greater FN (p = 0.009) and LS (p = 0.03) BMD. Each SD increment in lean mass loss and fat mass gain was associated with 63% (p = 0.001) and 28% (p = 0.05) greater fracture hazard after the MT; associations were essentially unchanged by BMD adjustment. MT-related lean mass loss and fat mass gain were associated differentially with BMD; both were independently related to more fractures. Mitigating MT-related body composition changes may reduce fracture risk. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Short-termed changes in quantitative ultrasound estimated bone density among young men in an 18-weeks follow-up during their basic training for the Swiss Armed Forces

Background

Quantitative Ultrasound (QUS) methods have been widely used to assess estimated bone density. This study aimed to assess changes in estimated bone density in association with changes in body composition, physical activity, and anthropometry.

Methods

We examined changes in anthropometry, body composition, and physical activity associated with changes in estimated bone mineral density (measured using quantitative ultrasound with a heel ultrasound device indicating broadband ultrasound attenuation BUA and speed of sound SOS) in a follow-up sample of n = 73 young men at the beginning and again 18 weeks later at the end of basic military training.

Results

At the end of the basic training, the subjects were on average significantly heavier (+1.0%), slightly taller (+0.5%) and had a higher fat mass (+6.6%) and grip strength (+8.6%). A significant decrease in mean physical activity (-49.5%) and mean estimated bone density calculated with BUA (-7.5%) was observed in the paired t-test. The results of the multivariable linear regressions (backward selection) show that changes in skeletal muscle mass (delta = 2nd measurement minus 1st measurement) have negative and body weight (delta) have positive association with the speed of sound SOS (delta), while fat mass (delta) and physical activity (delta) had the strongest negative associations with estimated bone mineral density (delta). In particular, we found a negative association between fat mass (delta) and estimated bone mineral density (delta, estimated with BUA).

Conclusion

Our study suggests that estimated bone density from the calcaneus can change within a few months even in young and mostly healthy individuals, depending upon physical activity levels and other co-factors. Further studies including other troop types as control groups as well as on women should follow in order to investigate this public health relevant topic in more depth. To what extent the estimated bone density measurement with quantitative ultrasound is clinically relevant needs to be investigated in further studies.

The Positive Association between Muscle Mass and Bone Status Is Conserved in Men with Diabetes: A Retrospective Cross-Sectional and Longitudinal Study

Bone and muscle are known to be correlated and interact chemically each other. Diabetes affects the health status of these two types of organ. There has been lack of studies of men on this topic. This study aims to investigate the relationship between bone and muscle status in men with and without diabetes. This study enrolled 318 and 88 men with and without diabetes, respectively, between April 2007 and December 2017. The appendicular skeletal muscle index (ASMI) was correlated with femoral neck bone mineral density (BMD), total hip BMD, and the trabecular bone score (TBS) in both groups (p < 0.001−0.008). In analysis of the changes in muscle mass and bone-related parameters over the 3 years, the ASMI was correlated with total hip BMD only in diabetes group (p = 0.016) and the TBS in both groups (p < 0.001−0.046). This study showed that the positive correlation between muscle mass and bone status was largely conserved in diabetic group in men. Moreover, in a long-term perspective, muscle mass might be more correlated with the bone microarchitecture or bone quality than bone density, and the association between muscle mass and total hip BMD could be stronger in the diabetic group.

A review of menopause nomenclature

Menopause nomenclature varies in the scholarly literature making synthesis and interpretation of research findings difficult. Therefore, the present study aimed to review and discuss critical developments in menopause nomenclature; determine the level of heterogeneity amongst menopause definitions and compare them with the Stages of Reproductive Aging Workshop criteria. Definitions/criteria used to characterise premenopausal and postmenopausal status were extracted from 210 studies and 128 of these studies were included in the final analyses. The main findings were that 39.84% of included studies were consistent with STRAW classification of premenopause, whereas 70.31% were consistent with STRAW classification of postmenopause. Surprisingly, major inconsistencies relating to premenopause definition were due to a total lack of reporting of any definitions/criteria for premenopause (39.84% of studies). In contrast, only 20.31% did not report definitions/criteria for postmenopause. The present findings indicate that there is a significant amount of heterogeneity associated with the definition of premenopause, compared with postmenopause. We propose three key suggestions/recommendations, which can be distilled from these findings. Firstly, premenopause should be transparently operationalised and reported. Secondly, as a minimum requirement, regular menstruation should be defined as the number of menstrual cycles in a period of at least 3 months. Finally, the utility of introducing normative age-ranges as supplementary criterion for defining stages of reproductive ageing should be considered. The use of consistent terminology in research will enhance our capacity to compare results from different studies and more effectively investigate issues related to women's health and ageing.

Bone Response to Weight Loss Following Bariatric Surgery

Obesity is a global health challenge that warrants effective treatments to avoid its multiple comorbidities. Bariatric surgery, a cornerstone treatment to control bodyweight excess and relieve the health-related burdens of obesity, can promote accelerated bone loss and affect skeletal strength, particularly after malabsorptive and mixed surgical procedures, and probably after restrictive surgeries. The increase in bone resorption markers occurs early and persist for up to 12 months or longer after bariatric surgery, while bone formation markers increase but to a lesser extent, suggesting a potential uncoupling process between resorption and formation. The skeletal response to bariatric surgery, as investigated by dual-energy X-ray absorptiometry (DXA), has shown significant loss in bone mineral density (BMD) at the hip with less consistent results for the lumbar spine. Supporting DXA studies, analyses by high-resolution peripheral quantitative computed tomography (HR-pQCT) showed lower cortical density and thickness, higher cortical porosity, and lower trabecular density and number for up to 5 years after bariatric surgery. These alterations translate into an increased risk of fall injury, which contributes to increase the fracture risk in patients who have been subjected to bariatric surgery procedures. As bone deterioration continues for years following bariatric surgery, the fracture risk does not seem to be dependent on acute weight loss but, rather, is a chronic condition with an increasing impact over time. Among the post-bariatric surgery mechanisms that have been claimed to act globally on bone health, there is evidence that micro- and macro-nutrient malabsorptive factors, mechanical unloading and changes in molecules partaking in the crosstalk between adipose tissue, bone and muscle may play a determining role. Given these circumstances, it is conceivable that bone health should be adequately investigated in candidates to bariatric surgery through bone-specific work-up and dedicated postsurgical follow-up. Specific protocols of nutrients supplementation, motor activity, structured rehabilitative programs and, when needed, targeted therapeutic strategies should be deemed as an integral part of post-bariatric surgery clinical support.

Associations of Fat Mass and Fat Distribution With Bone Mineral Density in Non-Obese Postmenopausal Chinese Women Over 60 Years Old

BACKGROUND

Bone mineral density (BMD) loss is a major complication of menopause, and this loss is closely associated with Fat mass (FM). The relationship between FM, fat distribution (FD), and BMD in postmenopausal women, however, remains incompletely understood. The present study was thus developed to explore these associations between body fat accumulation, FD, and BMD among non-obese postmenopausal women over the age of 60.

METHODS

This was a cross-sectional analysis of 357 healthy postmenopausal women between the ages of 60.2 and 86.7 years. Dual-energy X-ray absorptiometry (DXA) was utilized to measure total and regional BMD as well as fat-related parameters including total FM, android and gynoid fat, body fat percentage (BF%), and total lean mass (LM) for all subjects. The android-to-gynoid fat ratio (AOI) was used to assess FD. Pearson's correlation testing and multiple regression analyses were used to explore relationships among AOI, LM, FM, and BMD.

RESULTS

Both LM and FM were positively correlated with total and regional BMD in univariate analysis (all P < 0.01), whereas BMD was not significantly associated with AOI in any analyzed site other than the head. Multivariate linear regression models corrected for age, height, and years post-menopause, revealed a sustained independent positive relationship between FM and BMD (standard β range: 0.141 - 0.343, P < 0.01). The relationship between FM and BMD was unaffected by adjustment for LM (standard β range: 0.132 - 0.258, P < 0.01), whereas AOI had an adverse impact on BMD at most analyzed skeletal sites (total body, hip, femoral neck, arm, leg, and head) (standard β range: -0.093 to -0.232, P < 0.05). These findings were unaffected by using BF% in place of FM (standard β range: -0.100 to -0.232, P < 0.05).

CONCLUSIONS

In this cohort of non-obese postmenopausal women over the age of 60 from China, total FM was positively associated with BMD, while AOI was negatively correlated with BMD. As such, a combination of proper weight gain and the control of central obesity may benefit the overall bone health of women after menopause.

Bone parameters of elite athletes with oligomenorrhea and prevalence seeking medical attention: a cross-sectional study

INTRODUCTION

Since the definition of secondary amenorrhea is cessation of regular menses for more than 3 months, it is likely that athletes with irregular menstrual cycles, including oligomenorrhea, do not consider the condition as serious. However, the consequences of untreated oligomenorrhea have not been investigated in elite track and field athletes.

MATERIALS AND METHODS

The cohort consisted of 91 elite-level track and field athletes. Body compositions, including bone parameters and bone turnover markers (BTMs), were measured.

RESULTS

Among the 91 participants, 52 were eumenorrheic and 33 were oligomenorrheic. The eumenorrheic athletes had significantly higher bone mineral density (BMD) and bone mineral content (BMC) of the lumbar spine, lower extremities, and whole body than had the oligomenorrheic athletes (p < 0.01). There were no significant differences in BTMs between the two groups, but oligomenorrheic athletes had significantly lower percent body fat.

CONCLUSION

More than 40% of the elite-level female track and field athletes in this study reported menstrual disorders with oligomenorrhea as the most common. However, none sought medical attention. As compared to the eumenorrheic athletes, the oligomenorrheic athletes had lower BMC and BMD. Hence, if an athlete is oligomenorrheic, bone parameter measurements are considerably important.

Obesity and Bone Loss at Menopause: The Role of Sclerostin

Background. Peripheral fat tissue is known to positively influence bone health. However, evidence exists that the risk of non-vertebral fractures can be increased in postmenopausal women with obesity as compared to healthy controls. The role of sclerostin, the SOST gene protein product, and body composition in this condition is unknown. Methods. We studied 28 severely obese premenopausal (age, 44.7 ± 3.9 years; BMI, 46.0 ± 4.2 kg/m²) and 28 BMI-matched post-menopausal women (age, 55.5 ± 3.8 years; BMI, 46.1 ± 4.8 kg/m²) thorough analysis of bone density (BMD) and body composition by dual X-ray absorptiometry (DXA), bone turnover markers, sclerostin serum concentration, glucose metabolism, and a panel of hormones relating to bone health. Results. Postmenopausal women harbored increased levels of the bone turnover markers CTX and NTX, while sclerostin levels were non-significantly higher as compared to premenopausal women. There were no differences in somatotroph, thyroid and adrenal hormone across menopause. Values of lumbar spine BMD were comparable between groups. By contrast, menopause was associated with lower BMD values at the hip (p < 0.001), femoral neck (p < 0.0001), and total skeleton (p < 0.005). In multivariate regression analysis, sclerostin was the strongest predictor of lumbar spine BMD (p < 0.01), while menopausal status significantly predicted BMD at total hip (p < 0.01), femoral neck (p < 0.001) and total body (p < 0.05). Finally, lean body mass emerged as the strongest predictor of total body BMD (p < 0.01). Conclusions. Our findings suggest a protective effect of obesity on lumbar spine and total body BMD at menopause possibly through mechanisms relating to lean body mass. Given the mild difference in sclerostin levels between pre- and postmenopausal women, its potential actions in obesity require further investigation.

Can waist circumference be a predictor of bone mineral density independent of BMI in middle-aged adults?

BACKGROUND

Obesity and osteoporosis are major public health issues globally. The prevalence of these two diseases prompts the need to better understand the relationship between them. Previous studies, however, have yielded controversial findings on this issue. Therefore, our aim in this study was to evaluate the independent association between waist circumference (WC), as a marker of obesity, and the bone mineral density (BMD) of the lumbar spine among middle-aged adults using data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

Our analysis was based on NHANES data from 2011 to 2018, including 5084 adults, 40-59 years of age. A weighted multiple linear regression analysis was used to evaluate the association between WC and lumbar BMD, with smooth curve fitting performed for non-linearities.

RESULTS

After adjusting for BMI and other potential confounders, WC was negatively associated with lumbar BMD in men (β = -2.8, 95% CI: -4.0 to -1.6) and premenopausal women (β = -2.6, 95% CI: -4.1 to -1.1). On subgroup analysis stratified by BMI, this negative association was more significant in men with a BMI ≥30 kg/m2 (β = -4.1, 95% CI: -6.3 to -2.0) and in pre- and postmenopausal women with a BMI <25 kg/m2 (premenopausal women: β= -5.7, 95% CI: -9.4 to-2.0; postmenopausal women: β=-5.6, 95% CI: -9.7 to -1.6). We further identified an inverted U-shaped relationship among premenopausal women, with a point of inflection at WC of 80 cm.

CONCLUSIONS

Our study found an inverse relationship between WC and lumbar BMD in middle-aged men with BMI ≥30 kg/m2, and women with BMI <25 kg/m2.

Integrative analysis of genetic and clinical risk factors for bone loss in a Korean population

PURPOSE

The relative contribution of genetic and clinical factors for bone loss is not well known. This study aimed to investigate the annualized percentage change in total hip bone mineral density (BMD) and the genetic and clinical risk factors for bone loss in a Korean prospective cohort study over a 6-year period.

METHODS

We included 645 men aged ≥50 years and 683 postmenopausal women who had repeated BMD testing between 2007 and 2014. The association between covariates and annualized percentage change in hip BMD was analyzed through the multivariate linear regression analysis. A total of 2614 single-nucleotide polymorphisms (SNPs) from 23 known BMD-related candidate genes and genome-wise association study were investigated.

RESULTS

Hip bone loss increased more rapidly in women than in men with advancing age. Hip bone loss in men increased with lean mass (LM) loss (%/year) (P < 0.001) and current smoking (P = 0.024) and decreased with increasing waist circumference (WC) (P < 0.001), alcohol consumption (P = 0.049), and increase in red blood cell counts (P = 0.031). Decreasing WC (P = 0.009), LM loss (%/year) (P < 0.001), and years since menopause ≤ 3 years (P = 0.003) significantly correlated with hip bone loss in women aged 45-59 years. Hip bone loss in women aged ≥60 years increased with advancing age (P = 0.012), alcohol consumption (P = 0.028), LM loss (%/year) (P = 0.031), and fat mass loss (%/year) (P < 0.001) and decreased with increasing WC (P = 0.025). LRP5 rs498830 (β = 0.127, P = 0.007) and TNFSF11 rs7325635 (β = 0.146, P = 0.001) were the top SNPs related to hip bone loss in men and postmenopausal women, respectively. However, none of the SNPs were associated with hip bone loss after Benjamini-Hochberg adjustment.

CONCLUSION

In this study, decreasing WC and LM were significant risk factors for hip bone loss in both men and women. Those factors were also identified that had sex-specific or age-specific effects on hip bone loss. None of the SNPs were associated with hip bone loss after multiple testing adjustments. The understanding of the modifiable factors contributing to bone loss has been broadened, and this may have implications such as in developing individualized preventive strategy. Further studies are needed to better predict the risk for bone loss in men and women.

Predicting osteoporosis with body compositions in postmenopausal women: a non-invasive method

Background

The prevalence of osteoporosis is rising steadily as the aging population increases. Bone mineral density (BMD) assessment is a golden standard to establish the diagnosis of osteoporosis. However, the accessibility and radiation exposure limited its role in community screening. A more convenient approach for screening is suggested.

Methods

A total of 363 postmenopausal women over the age of 50 were included in this study and assessed with the body composition [including fat-free mass (FFM), fat mass (FM), and basal metabolic rate (BMR)] and BMD. Normal distributions and correlation coefficients among variables were calculated using the Shapiro-Wilk test and Pearson’s correlation analysis, respectively. A receiver operating characteristic (ROC) curve was plotted, and the area under ROC curves (AUC) was determined to obtain the optimal cutoff values of the body composition variables for osteoporosis prediction.

Results

The correlation coefficient of FFM, FM, FM ratio, and BMR with femur neck T-score was 0.373, 0.266, 0.165, and 0.369, respectively, while with spine T-score was 0.350, 0.251, 0.166, and 0.352, respectively (p < 0.01 for all). FFM, FM, and BMR showed an optimal cutoff value of 37.9 kg, 18.6 kg, and 1187.5 kcal, respectively, for detecting osteoporosis.

Conclusions

The present study provided a model to predict osteoporosis in postmenopausal women, and the optimal cutoff value of FFM, FM, and BMR could be calculated in the Asian population. Among these factors, BMR seemed a better predictor than others. The BMR could be a target for exercise intervention in postmenopausal women for maintaining or improving BMD.

Trial registration

ClinicalTrials.gov, NCT02936336. Retrospectively registered on13 October 2016.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02351-3.

Lean body mass, body fat percentage, and handgrip strength as predictors of bone mineral density in postmenopausal women

Objective:

This study was conducted to assess lean body mass, body fat percentage, and handgrip strength in the prediction of bone mineral density (BMD) in postmenopausal women.

Materials and Methods:

This cross-sectional study included 102 postmenopausal women aged between 45 and 80 years (mean age 58) who were screened for osteoporosis using a dual-energy X-ray absorptiometry scan at the lumbar spine. The lean body mass, body fat percentage, and handgrip strength were calculated.

Results:

The lean body mass, body fat percentage, and handgrip strength were having a positive association (correlation coefficient: 0.48, 0.29, and 0.3, respectively) with BMD.

Conclusion:

Lean body mass, body fat percentage, and handgrip strength can detect early loss of BMD in postmenopausal women leading to early screening for osteoporosis resulting in early interventions minimizing BMD loss over a much longer period after menopause.

Bone Mineral Density in Adolescent Boys: Cross-Sectional Observational Study

Physical inactivity of children can be a precursor of reduced bone mineral density, considered to be a typical problem only in old age. The aim of this study was to evaluate bone mineral density in 96 Polish boys aged 14–17 years with varied physical activity (swimmers, track and field athletes, non-athletes) and the effect of bone composition, birth weight and breastfeeding during infancy on bone parameters. Anthropometric and body composition measurements were performed according to the kinanthropometric standards. Bone parameters of the forearm were measured by means of dual-energy X-ray absorptiometry. Data on the infant’s birth weight and the length of breastfeeding were collected during direct interviews with mothers. The strongest links with bone parameters were found for the type of physical activity and birth weight. Regardless of birth weight, track and field athletes had the most advantageous bone parameters (mainly sT-score prox values). Swimmers with normal or low birth weight had less favourable sT-score prox values than non-athletes. The type of physical activity proved to be an important determinant of bone parameters. Childhood and adolescence are important periods of bone development and increasing the content of bone mineral components, and the bone status in later years of life depends to a large extent on this period. The perinatal period, especially the correct birth weight of the child, not only has a significant effect on general health, but also on bone status.

Relationship Between Non-alcoholic Fatty Liver Disease and Decreased Bone Mineral Density: A Retrospective Cohort Study in Korea

Objectives

The aim of this retrospective cohort study was to investigate whether non-alcoholic fatty liver disease (NAFLD) was associated with incident bone mineral density (BMD) decrease.

Methods

This study included 4536 subjects with normal BMD at baseline. NAFLD was defined as the presence of fatty liver on abdominal ultrasonography without significant alcohol consumption or other causes. Decreased BMD was defined as a diagnosis of osteopenia, osteoporosis, or BMD below the expected range for the patient’s age based on dual-energy X-ray absorptiometry. Cox proportional hazards models were used to estimate the hazard ratio of incident BMD decrease in subjects with or without NAFLD. Subgroup analyses were conducted according to the relevant factors.

Results

Across 13 354 person-years of total follow-up, decreased BMD was observed in 606 subjects, corresponding to an incidence of 45.4 cases per 1000 person-years (median follow-up duration, 2.1 years). In the model adjusted for age and sex, the hazard ratio was 0.65 (95% confidence interval, 0.51 to 0.82), and statistical significance disappeared after adjustment for body mass index (BMI) and cardiometabolic factors. In the subgroup analyses, NAFLD was associated with a lower risk of incident BMD decrease in females even after adjustment for confounders. The direction of the effect of NAFLD on the risk of BMD decrease changed depending on BMI category and body fat percentage, although the impact was statistically insignificant.

Conclusions

NAFLD had a significant protective effect on BMD in females. However, the effects may vary depending on BMI category or body fat percentage.

Visceral fat metabolic activity evaluated by 18F-FDG PET/CT is associated with osteoporosis in healthy postmenopausal Korean women

BACKGROUND

Traditionally, obesity has been regarded as protective against osteoporosis. However, recent accumulating evidences suggest that visceral obesity can increase the risk of osteoporosis and obesity-driven dysfunctional metabolic activity in visceral adipose tissue (VAT) is considered as a key underlying mechanism. Visceral obesity is known to increase during menopausal transition.¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) is an established method to assess the degree of VAT metabolic activity. We aimed to investigate the association between VAT metabolic activity evaluated by ¹⁸F-FDG PET/CT and osteoporosis in healthy postmenopausal Korean women.

METHODS

A total of 115 postmenopausal women who underwent routine health check-up were enrolled in this study, retrospectively. They all underwent dual-energy X-ray absorptiometry and ¹⁸F-FDG PET/CT. Osteoporosis was defined as bone mineral density (BMD) T-score ≤ -2.5 at either lumbar spine or femoral neck. VAT metabolic activity was defined as the maximum standardized uptake value (SUVmax) of VAT divided by the SUVmax of subcutaneous adipose tissue (V/S ratio).

RESULTS

The participants with osteoporosis showed significantly higher V/S ratio, age, body mass index, waist circumference, and postmenopausal period than the participants without osteoporosis. V/S ratio of 1.33 was proposed as an optimal cut-off value for identifying osteoporosis. Furthermore, V/S ratio was the most significant predictive factor for osteoporosis in postmenopausal woman by uni-and multivariate analyses. Interestingly, V/S ratio showed significant positive correlation with high sensitivity C-reactive protein, a surrogate marker for systemic inflammation.

CONCLUSION

VAT metabolic activity assessed by ¹⁸F-FDG PET/CT is associated with osteoporosis in healthy postmenopausal Korean women.

Sex differences in the patterning of age-related bone loss in the human hallucal metatarsal in rural and urban populations

OBJECTIVES

Age-degenerative features of the metatarsals are poorly known despite the importance of metatarsal bone properties for investigating mobility patterns. We assessed the role of habitual activity in shaping the patterning and magnitude of sexual dimorphism in age-related bone loss in the hallucal metatarsal.

MATERIALS AND METHODS

Cross-sections were extracted at midshaft from micro-computed tomography scan models of individuals from medieval rural (Abingdon Vineyard) and early industrial urban (Spitalfields) settings (n = 71). A suite of cross-sectional geometry dimensions and biomechanical properties were compared between populations.

RESULTS

The rural group display generally stronger and larger metatarsals that show a greater capacity to resist torsion and that have comparatively greater bending strength along the medio-lateral plane. Men in both groups show greater values of cortical area than women, but only in the urban group do men show lower magnitudes of age-related decline compared to females. Women in rural and urban populations show different patterns of age-related decline in bone mass, particularly old women in the urban group show a marked decline in cortical area that is absent for women in the rural group.

DISCUSSION

Lifetime exposure to hard, physical activity in an agricultural setting has contributed to the attainment of greater bone mass and stronger bones in young adults. Furthermore, over the life-course, less of this greater amount of bone is lost, such that sustained activity levels may have acted to buffer against age-related decline, and this is most pronounced for women, who are expected to experience greater bone loss later in life than men.

Fat mass changes during menopause: a metaanalysis

OBJECTIVE

Data: Fat mass has been shown to increase in aging women; however, the extent to which menopausal status mediates these changes remains unclear. The purpose of this review was to determine (1) how fat mass differs in quantity and distribution between premenopausal and postmenopausal women, (2) whether and how age and/or menopausal status moderates any observed differences, and (3) which type of fat mass measure is best suited to the detection of differences in fat mass between groups.

STUDY

This review with metaanalyses is reported according to Metaanalysis of Observational Studies in Epidemiology guidelines.

STUDY APPRAISAL AND SYNTHESIS METHODS

Studies (published up to May 2018) were identified via PubMed to provide fat mass measures in premenopausal and postmenopausal women. We included 201 cross-sectional studies in the metaanalysis, which provided a combined sample size of 1,049,919 individuals and consisted of 478,734 premenopausal women and 571,185 postmenopausal women. Eleven longitudinal studies were included in the metaanalyses, which provided a combined sample size of 2472 women who were premenopausal at baseline and postmenopausal at follow up.

RESULTS

The main findings of this review were that fat mass significantly increased between premenopausal and postmenopausal women across most measures, which included body mass index (1.14 kg/m²; 95% confidence interval, 0.95-1.32 kg/m²), bodyweight (1 kg; 95% confidence interval, 0.44-1.57 kg), body fat percentage (2.88%; 95% confidence interval, 2.13-3.63%), waist circumference (4.63 cm; 95% confidence interval, 3.90-5.35 cm), hip circumference (2.01 cm; 95% confidence interval, 1.36-2.65 cm), waist-hip ratio (0.04; 95% confidence interval, 0.03-0.05), visceral fat (26.90 cm²; 95% confidence interval, 13.12-40.68), and trunk fat percentage (5.49%; 95% confidence interval, 3.91-7.06 cm²). The exception was total leg fat percentage, which significantly decreased (-3.19%; 95% confidence interval, -5.98 to -0.41%). No interactive effects were observed between menopausal status and age across all fat mass measures.

CONCLUSION

The change in fat mass quantity between premenopausal and postmenopausal women was attributable predominantly to increasing age; menopause had no significant additional influence. However, the decrease in total leg fat percentage and increase in measures of central fat are indicative of a possible change in fat mass distribution after menopause. These changes are likely to, at least in part, be due to hormonal shifts that occur during midlife when women have a higher androgen (ie, testosterone) to estradiol ratio after menopause, which has been linked to enhanced central adiposity deposition. Evidently, these findings suggest attention should be paid to the accumulation of central fat after menopause, whereas increases in total fat mass should be monitored consistently across the lifespan.

Fatty infiltration of paraspinal muscles is associated with bone mineral density of the lumbar spine

A total of 88 subjects were enrolled to investigate the relationship between paraspinal muscle fatty infiltration and lumbar bone mineral density (BMD) using chemical shift encoding-based water-fat MRI and quantitative computed tomography (QCT), respectively. A moderate inverse correlation between paraspinal muscle proton density fat fraction and lumbar QCT-BMD was found with age, sex, and BMI controlled.

PURPOSE

To investigate the relationship between paraspinal muscle fatty infiltration and lumbar bone mineral density (BMD).

METHODS

A total of 88 subjects were enrolled in this study (52 females, 36 males; age, 46.6 ± 14.2 years old; BMI, 23.2 ± 3.49 kg/m²). Proton density fat fractions (PDFF) of paraspinal muscles (erector spinae, multifidus, and psoas) were measured at L2/3, L3/4, and L4/5 levels using chemical shift encoding-based water-fat MRI. Quantitative computed tomography (QCT) was used to assess BMD of L1, L2, and L3. The differences in paraspinal muscle PDFF among subjects with normal bone density, osteopenia, and osteoporosis were tested using one-way ANOVA. The relationship between paraspinal muscle PDFF and QCT-BMD was analyzed using linear regression with age, sex, and BMI variables.

RESULTS

PDFF of the erector spinae, multifidus, and psoas of subjects with normal bone density were all significantly less than those with osteopenia and those with osteoporosis (all p < 0.001). There was an inverse correlation between paraspinal muscle PDFF and BMD after controlling for age, sex, and BMI (standardized beta coefficient, - 0.21~- 0.29; all p < 0.05).

CONCLUSIONS

Paraspinal muscle fatty infiltration increased while lumbar BMD decreased after adjusting for age, sex, and BMI. Paraspinal muscles and vertebrae are interacting tissues. Paraspinal muscle fatty infiltration may be a marker of low lumbar BMD. Chemical shift imaging is an efficient and fast quantitative method and can be easily added to the clinical protocol to measure paraspinal muscle PDFF when the patient underwent the routine lumbar MRI with low-back pain.

Association of Osteoporosis with Anthropometric Measures in a Representative Sample of Iranian Adults: The Iranian Multicenter Osteoporosis Study

BACKGROUND

Osteoporosis and obesity are two major public health problems worldwide. Considering the conflicting results about the association between anthropometric measurement and bone mineral density (BMD) and also differences between various races, this study was designed to examine the relationship between anthropometric measurements and BMD in a sample of Iranian adults.

METHODS

This cross-sectional population-based study was conducted on 2625 Iranian adults aged 18 and above who were selected using multistage, cluster sampling method from Sanandaj and Arak (two cities of Iran). The evaluated variables included age, sex, height, weight, body mass index (BMI), BMD, and waist and hip circumferences. The correlations between anthropometric measures and BMD in three bone areas (total hip, femoral neck, and spine) were observed in four sex/age groups (men <50 years, men ≥50 years, and pre- and postmenopausal women).

RESULTS

Of all the 2625 participants in the Iranian Multicenter Osteoporosis Study, 2022 (1303 women and 719 men) entered into our survey and were stratified into four sex/age groups. According to the results, increasing BMI was directly associated with BMD increase, while an inverse association was observed between waist-to-hip ratio (WHR) and total hip BMD. In a similar analysis on the femoral neck and WHR, the correlation coefficients in premenopausal women and men ≥50 years were reported as being the highest and the lowest, respectively, among the four groups.

CONCLUSIONS

Our results showed that high BMI is a protective factor (positive correlation), and high WHR is a risk factor for osteoporosis, although it should be reminded that we could not specifically define which factors including lean tissue mass, fat mass, and total weight are really affecting BMD increase in the overweight/obese participants.

Is waist circumference a negative predictor of calcaneal bone mineral density in adult Chinese men with normal weight?

Background

Our study aimed to evaluate the association between waist circumference (WC) and calcaneal bone mineral density (BMD) in adult Chinese men with normal weight.

Methods

This was a cross-sectional study. A total of 4,663 male participants aged 40 years or older residing in Ningde and Wuyishan, two cities locating in Fujian province of China, were randomly recruited between 2011 and 2012. Each participant should complete a standard questionnaire, undergo anthropometric and calcaneus quantitative ultrasound (QUS) measurements and have blood sample taken. Anthropometric, biochemical and calcaneal QUS parameters of 1,583 male participants with BMI ranging from 18.5 to 22.9 were included in the analysis. WC was divided into quartiles (Q1-Q4: <71, 71-75, 75-78, >78 cm). The relationship between WC (quartiles) and BMD was analyzed by multiple linear regression models.

Results

Mean age of the whole population was 54.6±9.8 years. Anthropometric and biochemical parameters were almost normal. Multiple linear regression analysis showed that BMD was negatively associated with increasing WC quartiles except for Q2 after adjusting for age and BMI, and this relationship remained negative except for Q2 when further adjustment was made for other covariates. Multiple logistic regression model also showed that the risks of osteopenia and osteoporosis increased across WC quartiles.

Conclusions

The present study indicated that WC was a negative predictor of calcaneal BMD in adult Chinese men with normal weight. It suggests that, even for the normal-weight Asian males, monitoring accrual of abdominal adipose is still helpful for the purpose of preventing bone loss.

Association of body composition with predicted hip bone strength among Chinese postmenopausal women: a longitudinal study

Body composition and bone strength are closely associated. How lean mass (LM) and fat mass (FM) contribute to bone strength remains ambiguous. We investigated the associations of total body LM and FM with changes in predicted hip bone strength over a period of 3 years in 1,743 postmenopausal Chinese women from the communities of Guangzhou, China. The body compositions of the women were obtained with dual-energy X-ray absorptiometry. We used the hip structure analysis program to obtain the bone parameters at the femoral neck region, including the bone mineral density (BMD), cross-sectional area (CSA), cortical thickness (CT), section modulus (SM) and buckling ratio (BR). We found the FM and LM were positive predictors for hip bone strength (β > 0, P < 0.05). The LM had a larger contribution to the BMD, CSA, CT, SM and/or their annual percent changes (βLM > βFM), while the contribution of FM to the BR and its annual percent change was higher than LM (|βFM| > |βLM|). Further analysis found that the associations of FM and LM with bone parameters were stronger in the underweight and normal weight participants (|βBMI1| > |βBMI2|). Overall, FM and LM had positive but differential effects on predicted hip bone strength, with a higher impact in the thinner participants.

Long-term childhood body mass index and adult bone mass are linked through concurrent body mass index and body composition

Body mass plays a crucial role in the bone growth and development, but few studies have examined the association of long-term cumulative impact and trajectory patterns of childhood body mass index (BMI) with adult bone mass, and the mediation effect of adult BMI and body composition on these associations. A total of 397 Chinese adults (54.4%) who had been examined for BMI 4-8 times during childhood (6-19 years) and bone mass in adulthood (29-37 years), were included for analysis. Adult bone mineral content (BMC), areal bone mineral density (aBMD) and body composition were assessed via dual-energy x-ray absorptiometry. Childhood BMI growth curves were constructed using a random-effects mixed model. The area under the curve (AUC) was calculated to represent the long-term impact of childhood BMI. At baseline, 24.4%, 66.2%, 7.6% and 1.8% of the participants were underweight, normal weight, overweight and obese, respectively. Quadratic curve parameters of childhood BMI differed significantly between groups of adult whole body (WB) BMC, lumbar spine (LS) aBMD and femoral neck (FN) aBMD, with low BMC/aBMD groups having lower childhood BMI than the normal groups. AUC of childhood BMI was significantly and positively related to adult WB BMC and aBMD at each site, irrespective of sex. Significant mediation effects of adult BMI were shown on the association of childhood BMI AUC with adult WB BMC in males (52.0%) and FN aBMD in both sexes (males: 65.4%; females: 64.3%). Additionally, mediation effect of fat mass index was only noted on the association of childhood BMI AUC with adult WB BMC (41.3%), with a positive total indirect effect estimated at 0.118. The adult lean mass index, by contrast, mediated the childhood BMI-adult BMC/aBMD association positively at all sites in males (71.5%~89.2%) and at WB BMC in females (45.0%). These findings suggest that the impact of body weight on adult bones originates from childhood, which is mediated by concurrent BMI and body composition.

Exploring the link between metabolic syndrome and risk of dysmobility syndrome in elderly population

Dysmobility syndrome (DMS) was considered as a comprehensive approach to evaluate the condition of musculoskeletal system and adverse health problems in older population. The objective of our study was to examine the association between metabolic syndrome (MetS) and DMS in a U.S. adult population. 1760 eligible participants from the National Health and Nutrition Examination Survey (NHANES) 1999-2002 were enrolled in the study. The criteria of DMS consisted of six domains including increased body fat, declined muscle mass, reduced muscle strength, osteoporosis, slow gait speed, and balance problem. A multivariate regression analysis was investigated to clarify the relationship among MetS and its components and DMS. A positive association between increased number of MetS components and the presence of DMS achieved significance (β = 0.142, 95%CI = 0.035, 0.249, p = 0.009). Among the components of MetS, hyperglycemia had a central place in the DMS after adjustment of clinical variables (β = 0.083, 95%CI = 0.030, 0.136, p = 0.002). Notably, insulin resistance assessed by homeostatic model assessment (HOMA-IR) was correlated to increased body fat (r = 0.092, p<0.05), osteoporosis (r = -0.105, p<0.05) and balance (r = 0.105, p<0.05) among these participants with MetS. Our study demonstrated a strong relationship between DMS and the presence of MetS and its components in elderly population, highlighting a possible mechanism through insulin resistance.

Association between Body Fat and Bone Mineral Density in Normal-Weight Middle-Aged Koreans

Background

Osteoporosis and osteopenia are characterized by reduced bone mineral density (BMD) and increased fracture risk. Although the risk of fractures is higher in underweight people than in overweight people, the accumulation of body fat (especially abdominal fat) can increase the risk of bone loss. This study aimed to evaluate the association between body fat percentage and BMD in normal-weight middle-aged Koreans.

Methods

This study included 1,992 adults (mean age, 48.7 years; 52.9% women). BMD and body fat were measured using dual-energy X-ray absorptiometry. Multiple linear regression analyses and analysis of covariance were used to assess the association between BMD and body fat. Body fat percentage was grouped by cut-off values. The cut-off values were 20.6% and 25.7% for men with a body mass index of 18.5–22.9 kg/m², while the cut-off values were 33.4% and 36% for women.

Results

Body fat percentage tended to be negatively associated with BMD. Increased body fat percentage was associated with reduced BMD in normal-weight middle-aged adults. The effects of body fat percentage on BMD in normal-weight individuals were more pronounced in men than in women.

Conclusion

There was a negative correlation between BMD and body fat percentage in middle-aged Korean men and women with normal body weight. This association was stronger in men than in women.

Lean Body Mass in the Prediction of Bone Mineral Density in Postmenopausal Women

Owing to conflicting results of the association between body composition and bone mineral density (BMD), we investigated the relationship between fat mass (FM), lean mass (LM), and BMD in New Zealand postmenopausal women. We hypothesized that increased LM will indicate a higher BMD. A cross-sectional study was performed examining the associations between body composition, anthropometric measures, activity energy expenditure, and bone health status (using dual-energy X-ray absorptiometry [DXA]). A total of 127 healthy postmenopausal women aged between 54 and 81 years. Both FM and LM were significantly associated with BMD at all sites. However, LM, not FM, was the strongest predictor of femoral neck (FN) BMD (β = 0.497, p < 0.001), hip BMD (β = 0.495, p < 0.001), spine BMD (β = 0.449, p < 0.001), and whole body BMD (β = 0.406, p < 0.001). Age was negatively associated with FN and hip BMD. LM was positively associated with FN, spine, hip, and whole body BMD. Our findings suggest the need to increase LM rather than FM highlighting the importance of physical activity for this age group.

Epicardial Fat Thickness and Bone Mineral Content: The Healthy Twin Study in Korea

Background

The conventional concept of positive association between general obesity and bone health was challenged in recent studies reporting the different effects of specific fat deposition on bone health. In the present study, we investigated the association between epicardial fat and bone health.

Methods

We measured echocardiographic epicardial fat thickness (EFT) and bone mineral content (BMC) in a twin-family cohort of Koreans (n = 1,198; 525 men, 460 pre- and 213 post-menopausal women). A total 121 pairs of monozygotic twin (MZ) and 404 pairs of dizygotic twin and sibling pairs (DZ/Sib) were included.

Results

EFT was positively associated with BMC in total, as well as in three subgroups (β = 0.107, 0.076, and 0.058 for men, pre-, and post-menopausal women, respectively). The positive association between EFT and BMC remained for DZ/Sib difference analysis, but was absent for MZ comparisons. The positive association between BMI and BMC was consistent for DZ/Sib and MZ difference analysis. After adjusting for the effect of general obesity via BMI, the association between BMC and EFT was statistically non-significant (β = 0.020, 0.000, and −0.009 for men, pre-, and post-menopausal women, respectively).

Conclusion

Our findings do not support epicardial fat’s beneficial effects on bone health, whereas general adiposity has an osteotropic effect. The association between EFT and BMC is through common genetic component factors.

The Association between Fat Mass, Lean Mass and Bone Mineral Density in Premenopausal Women in Korea: A Cross-Sectional Study

Background

We investigated the association between body composition, especially truncal or non-truncal fat mass (FM), and bone mineral density (BMD) in premenopausal women in Korea.

Methods

A cross-sectional study was performed using data from the Korea National Health and Nutrition Examination Survey IV and V (2008–2011). Total lean mass (LM), total FM (TFM), truncal FM, and non-truncal FM, and BMD of the total femur, femoral neck (FN), and lumbar spine were measured using dual-energy X-ray absorptiometry. The association between body composition and BMD was analyzed using multiple linear regression. The risk of low BMD according to quartiles of TFM, truncal FM, and non-truncal FM was calculated using logistic regression. Subgroup analysis according to body mass index was also performed.

Results

In 4,343 premenopausal women, total LM was positively associated with BMD regardless of weight adjustment. TFM, truncal FM, and non-truncal FM were inversely associated with BMD after adjusting for weight. Odds ratios (ORs) for low BMD and 95% confidence intervals (CIs) of the highest quartile of TFM, truncal FM, and non-truncal FM compared with the lowest quartile were calculated. The risk of low BMD of the FN was higher in the highest quartile of TFM (OR, 4.48; 95% CI, 1.11–18.01) and truncal FM (OR, 5.48; 95% CI, 1.75–17.20). Truncal FM and not-truncal FM had an inverse association with BMD in the non-obese and obese subgroups of women.

Conclusion

Total LM has a protective effect on BMD and FM can have a detrimental effect on BMD besides its skeletal loading effect.

Influence of adipose tissue mass on bone mass in an overweight or obese population: systematic review and meta-analysis

Context

The scientific literature shows conflicting evidence about the relationship between adiposity and bone mass in overweight and obese populations. The aim of this review was to quantify the correlation between adipose mass (absolute and relative) and bone mineral density (BMD) in overweight and obese populations. Three databases were searched electronically. In addition, reference lists of relevant articles were screened. A total of 16 studies, comprising 2587 participants and 75 correlation coefficients were selected for inclusion in the review. Data were extracted from each study using a standardized form. Multilevel modeling indicated opposing relationships between BMD and adiposity: absolute adiposity correlated positively, and relative adiposity negatively, with BMD. Sex and age were the primary moderators of these relationships. Strong evidence supported a negative relationship between relative adipose mass and BMD in men (R = -0.37; 95%CI, -0.57 to -0.12) and in those aged less than 25 years (R = -0.28; 95%CI, -0.45 to -0.08). To prevent bone loss in overweight and obese populations, nutrition- and exercise-based interventions that focus on a controlled reduction of adipose mass with concomitant preservation of lean mass are recommended. : PROSPERO no. CRD42015024313.

Sex-based Differences in the Association between Body Composition and Incident Fracture Risk in Koreans

The relative contribution of lean mass and fat mass on bone health is inconclusive. We investigated the relative contributions of lean and fat masses on fragility fracture risk in Korean men and women. This was an ongoing prospective community-dwelling cohort study at Ansung beginning in 2001, which included 2,189 men and 2,625 women over 40 years old. Study subjects were classified into the following four groups according to lean mass (LM)/height² and percentage fat mass (PF). Clinical fragility fracture events were assessed at baseline and biennially using self-reported questionnaires. During a median follow-up of 9.4 years, 77 (3.5%) men and 203 (7.7%) women experienced at least one incident fracture. In Cox proportional hazard models, men with low LM under normal and high PF had a 2.16 and 2.59- fold higher risk for fragility fractures than normal ones even after adjusting for covariates. However, in women, low LM or high FM was not associated with fracture risk. We demonstrated sex-based differences in the association of body composition and incident fracture risk in Koreans aged over 40 years during a 10-year follow-up duration. Maintaining muscle mass in men is vital to maintaining bone health and preventing fragility fractures in Koreans.

Association of insulin resistance with near peak bone mass in the femur and lumbar spine of Korean adults aged 25-35: The Korean National Health and Nutrition Examination Survey 2008-2010

Objective

This study aimed to evaluate the relationship between insulin resistance and the bone mineral density (BMD) of femur and lumbar spine in Korean adults who are expected to exhibit near peak bone mass.

Methods

Data from the Korean National Health and Nutrition Examination Survey 2008–2010 were analyzed. A total of 2,750 participants aged 25−35 years were included. Insulin resistance was assessed using a homeostatic model assessment of insulin resistance (HOMA-IR) and serum fasting insulin.

Results

In a multivariate linear regression analysis, the HOMA-IR was significantly inversely associated with the BMD of the total hip (TH, β = −0.052, P = 0.002), femoral neck (FN, β = −0.072, P<0.001), femoral trochanter (FTr, β = −0.055, P = 0.003), femoral intertrochanter (FITr, β = −0.041, P = 0.015), and lumbar spine (LS, β = −0.063, P = 0.001) among all study subjects after adjustment for gender, age, height, weight, whole body fat mass percentage, systolic blood pressure, diastolic blood pressure, total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, vitamin D, smoking, alcohol intake, physical activity, education level, and household income in both genders as well as labor, the use of oral contraceptives, and age at menarche in females. The serum fasting insulin was significantly inversely associated with the BMD of the TH (β = −0.055, P = 0.001), FN (β = −0.072, P<0.001), FTr (β = −0.055, P = 0.003), FITr (β = −0.045, P = 0.009), and LS (β = −0.064, P = 0.001) among all subjects in a multivariate linear regression analysis.

Conclusion

Our results suggest that insulin resistance may be independently and inversely associated with the near peak bone mass of the femur and lumbar spine.

Gut microbiota-bone axis

The gut microbiota (GM) is an important regulator of body homeostasis, including intestinal and extra-intestinal effects. This review focuses on the GM-bone axis, which we define as the effect of the gut-associated microbial community or the molecules they synthesize, on bone health. While research in this field is limited, findings from preclinical studies support that gut microbes positively impact bone mineral density and strength parameters. Moreover, administration of beneficial bacteria (probiotics) in preclinical models has demonstrated higher bone mineralization and greater bone strength. The preferential bacterial genus that has shown these beneficial effects in bone is Lactobacillus and thus lactobacilli are among the best candidates for future clinical intervention trials. However, their effectiveness is dependent on stage of development, as early life constitutes an important time for impacting bone health, perhaps via modulation of the GM. In addition, sex-specific difference also impacts the efficacy of the probiotics. Although auspicious, many questions regarding the GM-bone axis require consideration of potential mechanisms; sex-specific efficacy; effective dose of probiotics; and timing and duration of treatment.

Obesity is a concern for bone health with aging

Accumulating evidence supports a complex relationship between adiposity and osteoporosis in overweight/obese individuals, with local interactions and endocrine regulation by adipose tissue on bone metabolism and fracture risk in elderly populations. This review was conducted to summarize existing evidence to test the hypothesis that obesity is a risk factor for bone health in aging individuals. Mechanisms by which obesity adversely affects bone health are believed to be multiple, such as an alteration of bone-regulating hormones, inflammation, oxidative stress, the endocannabinoid system, that affect bone cell metabolism are discussed. In addition, evidence on the effect of fat mass and distribution on bone mass and quality is reviewed together with findings relating energy and fat intake with bone health. In summary, studies indicate that the positive effects of body weight on bone mineral density cannot counteract the detrimental effects of obesity on bone quality. However, the exact mechanism underlying bone deterioration in the obese is not clear yet and further research is required to elucidate the effect of adipose depots on bone and fracture risk in the obese population.

Association between Obesity and Bone Mineral Density by Gender and Menopausal Status

BACKGROUND

We investigated whether there were gender differences in the effect of obesity on bone mineral density (BMD) based on menopausal status.

METHODS

We assessed 5,892 consecutive patients 20 to 91 years old who were referred for dual-energy X-ray absorptiometry (DXA) scans. All subjects underwent a standard BMD scan of the hip (total hip and femoral neck) and lumbar spine (L1 to L4) using a DXA scan and body size assessment. Body mass index was used to categorize the subjects as normal weight, overweight, and obese.

RESULTS

BMD was higher in obese and overweight versus normal weight men, premenopausal women, and postmenopausal women. Compared to men ≥50 years and postmenopausal women with normal weight, the age-adjusted odds ratio of osteopenia was 0.19 (95% confidence interval [CI], 0.07 to 0.56) and 0.38 (95% CI, 0.29 to 0.51) for obese men ≥50 years and postmenopausal women. Corresponding summaries for osteoporosis were 0.26 (95% CI, 0.11 to 0.64) and 0.15 (95% CI, 0.11 to 0.20), respectively. Compared to men <50 years and premenopausal women with normal weight, the age-adjusted odds ratio of low bone mass was 0.22 (95% CI, 0.11 to 0.45) and 0.16 (95% CI, 0.10 to 0.26) for obese men <50 years and premenopausal women, respectively.

CONCLUSION

Obesity is associated with BMD of the hip and lumbar spine and overweight and obese individuals have similar degrees of osteoporosis. This result was not significantly different based on gender and menopausal status, which could be an important issue for further investigation.

Palmitic Acid Reduces Circulating Bone Formation Markers in Obese Animals and Impairs Osteoblast Activity via C16-Ceramide Accumulation

Obesity and impaired lipid metabolism increase circulating and local fatty acid (FA) levels. Our previous studies showed that a high high-saturated -fat diet induced greater bone loss in mice than a high high-unsaturated-fat diet due to increased osteoclast numbers and activity. The impact of elevated FA levels on osteoblasts is not yet clear. We induced obesity in 4 week old male mice using a palmitic acid (PA)- or oleic acid (OA)-enriched high fat high-fat diet (HFD) (20 % of calories from FA), and compared them to mice on a normal (R) caloric diet (10 % of calories from FA). We collected serum to determine FA and bone metabolism marker levels. Primary osteoblasts were isolated; cultured in PA, OA, or control (C) medium; and assessed for mineralization activity, gene expression, and ceramide levels. Obese animals in the PA and OA groups had significantly lower serum levels of bone formation markers P1NP and OC compared to normal weight animals (*p < 0.001), with the lowest marker levels in animals on an PA-enriched HFD (*p < 0.001). Accordingly, elevated levels of PA significantly reduced osteoblast mineralization activity in vitro (*p < 0.05). Elevated PA intake significantly increased C16 ceramide accumulation. This accumulation was preventable through inhibition of SPT2 (serine palmitoyl transferase 2) using myriocin. Elevated levels of PA reduce osteoblast function in vitro and bone formation markers in vivo. Our findings suggest that saturated PA can compromise bone health by affecting osteoblasts, and identify a potential mechanism through which obesity promotes bone loss.

Regional body fat depots differently affect bone microarchitecture in postmenopausal Korean women

SUMMARY

In a prospective community-based cohort study, we investigated the relationship between trabecular bone score (TBS) and regional fat depots in 1474 Korean postmenopausal women. TBS was positively related with subcutaneous fat and negatively related with visceral fat.

INTRODUCTION

The effect of fat distribution (visceral/subcutaneous) on bone quality or microarchitecture has rarely been investigated due to measurement difficulty. We aimed to investigate the relationship between TBS reflecting bone microarchitecture and regional fat depots in Korean women.

METHODS

Cross-sectional data evaluation was made from subjects participating in an ongoing prospective community-based cohort study since 2001. A total of 1474 postmenopausal women in the Ansung cohort were analyzed. Regional body fat mass, bone mineral density (BMD) at the lumbar spine, and total hip and lumbar spine TBS were measured by dual energy X-ray absorptiometry (DXA).

RESULTS

In an age-adjusted partial correlation analysis, TBS was not associated with total fat mass, but negatively associated with trunk fat mass. However, TBS was positively related with leg (r = 0.102, P < 0.05) and gynoid fat mass (r = 0.086, P < 0.05) and negatively related with android fat mass (r = -0.106; P < 0.05). In linear regression models controlling age, BMI, and physical activity, android fat was inversely associated with TBS (β = -0.595, P < 0.001), whereas gynoid fat was positively associated with TBS (β = 0.216, P < 0.001). Lumbar spine and total hip BMDs revealed positive associations with total and all regional fat depots regardless of fat distribution.

CONCLUSION

Our findings suggest that relatively large visceral fat and small subcutaneous fat may have a detrimental effect on TBS, a bone microarchitecture index.

Relationship of sarcopenia and body composition with osteoporosis

The purpose of the study is to investigate the relationship between sarcopenia and body composition and osteoporosis in cohorts of three different races with a total of 17,891 subjects. Lean mass and grip strength were positively associated with bone mineral densities (BMDs). Subjects with sarcopenia were two times more likely to have osteoporosis compared with normal subjects.

INTRODUCTION

The relationship between sarcopenia and osteoporosis is not totally clear. First, the present study assessed this relationship by using two different definitions for sarcopenia. Second, we examined the associations of body composition (including muscle mass as a major and important component) and muscle strength on regional and whole-body BMDs.

METHODS

In total, 17,891 subjects of African American, Caucasian, and Chinese ethnicities were analyzed. Sarcopenia was defined by relative appendicular skeletal muscle mass (RASM) cut points and also by the definition of the European Working Group on Sarcopenia in Older People (low RASM plus low muscle function). Multiple regression analyses were conducted to examine the association of fat mass, lean mass (including muscle mass), and grip strength with regional and whole-body BMDs. Multivariate logistic regression analysis was performed to explore the association between sarcopenia and osteopenia/osteoporosis.

RESULTS

BMDs were positively associated with lean mass and negatively associated with fat mass, after controlling for potential confounders. Grip strength was significantly associated with higher BMDs. Each standard deviation (SD) increase in RASM resulted in a ~37 % reduction in risk of osteopenia/osteoporosis (odds ratio (OR) = 0.63; 95 % confidence interval (CI) = 0.59, 0.66). Subjects with sarcopenia defined by RASM were two times more likely to have osteopenia/osteoporosis compared with the normal subjects (OR = 2.04; 95 % CI = 1.61, 2.60). Similarly, subjects with sarcopenia (low muscle mass and low grip strength) were ~1.8 times more likely to have osteopenia/osteoporosis than normal subjects (OR = 1.87; 95 % CI = 1.09, 3.20).

CONCLUSIONS

High lean mass and muscle strength were positively associated with BMDs. Sarcopenia is associated with low BMD and osteoporosis.

Contributions of fat mass and fat distribution to hip bone strength in healthy postmenopausal Chinese women

The fat and bone connection is complicated, and the effect of adipose tissue on hip bone strength remains unclear. The aim of this study was to clarify the relative contribution of body fat accumulation and fat distribution to the determination of proximal femur strength in healthy postmenopausal Chinese women. This cross-sectional study enrolled 528 healthy postmenopausal women without medication history or known diseases. Total lean mass (LM), appendicular LM (ALM), percentage of lean mass (PLM), total fat mass (FM), appendicular FM (AFM), percentage of body fat (PBF), android and gynoid fat amount, android-to-gynoid fat ratio (AOI), bone mineral density (BMD), and proximal femur geometry were measured by dual energy X-ray absorptiometry. Hip structure analysis was used to compute some variables as geometric strength-related parameters by analyzing the images of the hip generated from DXA scans. Correlation analyses among anthropometrics, variables of body composition and bone mass, and geometric indices of hip bone strength were performed with stepwise linear regression analyses as well as Pearson's correlation analysis. In univariate analysis, there were significantly inverse correlations between age, years since menopause (YSM), hip BMD, and hip geometric parameters. Bone data were positively related to height, body weight, LM, ALM, FM, AFM, and PBF but negatively related to AOI and amount of android fat (all P < 0.05). AFM and AOI were significantly related to most anthropometric parameters. AFM was positively associated with height, body weight, and BMI. AFM was negatively associated with age and YSM. AOI was negatively associated with height, body weight, and BMI. AOI positively associated with age and YSM. LM, ALM, and FM had a positive relationship with anthropometric parameters (P < 0.05 for all). PLM had a negative relationship with those parameters. The correlation between LM, ALM, FM, PLM, ALM, age, and YSM was not significant. In multivariate linear regression analysis, the hip bone strength was observed to have a consistent and unchanged positive association with AFM and a negative association with AOI, whereas its association with other variables of body composition was not significant after adjusting for age, years since menopause, height, body weight, and BMI. AFM may be a positively protective effect for hip bone strength while AOI, rather than android fat, shows a strong negative association with hip bone strength after making an adjustment for confounders (age, YSM, height, body weight, and BMI) in healthy postmenopausal Chinese women. Rational weight control and AOI reduction during menopause may have vital clinical significance in decreasing postmenopausal osteoporosis.

Risk Factors of Bone Mass Loss at the Lumbar Spine: A Longitudinal Study in Healthy Korean Pre- and Perimenopausal Women Older than 40 Years

Longitudinal studies on bone mass decline for healthy women are sparse. We performed a retrospective longitudinal study to evaluate the factor associated with bone mass changes at the lumbar spine in healthy Korean pre- and perimenopausal women over the age of 40. We examined the relation of blood tests including thyroid function tests at baseline and follow-up to the annual percentage changes in average BMD of L2-L4 (A%ΔLSBMD). Four hundred and forty-three subjects without diseases or medications pertaining to bone metabolism were analyzed. The mean A%ΔLSBMD in these subjects was -0.45%/year. Though a significant correlation was observed between the A%ΔLSBMD and age, serum thyroid-stimulating hormone (TSH) level, total cholesterol (TC) level, low-density lipoprotein cholesterol (LDL-C) level, and estimated glomerular filtration rate (eGFR) at baseline and follow-up, there was a weak correlation between A%ΔLSBMD and these variables. From multiple linear regression analyses, the percent body fat, age, serum TSH level, serum uric acid level, and the menopause at follow-up were showed to have a significant association with the A%ΔLSBMD. Unlike age, percent body fat, and menopause at follow-up, which had a negative association with the A%ΔLSBMD, serum TSH level and serum uric acid level, had a positive association with the A%ΔLSBMD. The results from our study showed that the notable risk factors of BMD loss at the lumbar spine in population of our study were advancing age, menopause, higher percent body fat, lower normal TSH, and lower serum uric acid levels.

Aged-Related Changes in Body Composition and Association between Body Composition with Bone Mass Density by Body Mass Index in Chinese Han Men over 50-year-old

OBJECTIVES

Aging, body composition, and body mass index (BMI) are important factors in bone mineral density (BMD). Although several studies have investigated the various parameters and factors that differentially influence BMD, the results have been inconsistent. Thus, the primary goal of the present study was to further characterize the relationships of aging, body composition parameters, and BMI with BMD in Chinese Han males older than 50 years.

METHODS

The present study was a retrospective analysis of the body composition, BMI, and BMD of 358 Chinese male outpatients between 50 and 89 years of age that were recruited from our hospital between 2009 and 2011. Qualified subjects were stratified according to age and BMI as follows: 50-59 (n = 35), 60-69 (n = 123), 70-79 (n = 93), and 80-89 (n = 107) years of age and low weight (BMI: < 20 kg/m2; n = 21), medium weight (20 ≤ BMI < 24 kg/m2; n = 118), overweight (24 ≤ BMI < 28 kg/m2; n = 178), and obese (BMI ≥ 28 kg/m2; n = 41). Dual-energy X-ray absorptiometry (DEXA) was used to assess bone mineral content (BMC), lean mass (LM), fat mass (FM), fat-free mass (FFM), lumbar spine (L1-L4) BMD, femoral neck BMD, and total hip BMD. Additionally, the FM index (FMI; FM/height2), LM index (LMI; LM/height2), FFM index (FFMI; [BMC+LM]/height2), percentage of BMC (%BMC; BMC/[BMC+FM+LM] × 100%), percentage of FM (%FM; FM/[BMC+FM+LM] × 100%), and percentage of LM (%LM; LM/(BMC+FM+LM) × 100%) were calculated. Osteopenia or osteoporosis was identified using the criteria and T-score of the World Health Organization.

RESULTS

Although there were no significant differences in BMI among the age groups, there was a significant decline in height and weight according to age (p < 0.0001 and p = 0.0002, respectively). The LMI and FFMI also declined with age (both p < 0.0001) whereas the FMI exhibited a significant increase that peaked in the 80-89-years group (p = 0.0145). Although the absolute values of BMC and LM declined with age (p = 0.0031 and p < 0.0001, respectively), there was no significant difference in FM. In terms of body composition, there were no significant differences in %BMC but there was an increase in %FM (p < 0.0001) and a decrease in %LM (p < 0.0001) with age. The femoral neck and total hip BMD significantly declined with age (p < 0.0001 and p = 0.0027, respectively) but there were no differences in L1-L4. BMD increased at all sites (all p < 0.01) as BMI increased but there were declines in the detection rates of osteoporosis and osteopenia (both p < 0.001). A logistic regression revealed that when the medium weight group was given a BMI value of 1, a decline in BMI was an independent risk factor of osteoporosis or osteopenia, while an increase in BMI was a protective factor for BMD. At the same time, BMD in L1-L4 exhibited a significant positive association with FMI (p = 0.0003) and the femoral neck and total hip BMDs had significant positive associations with FFMI and LMI, respectively (both p < 0.0001).

CONCLUSIONS

These data indicate that LMI and FFMI exhibited significant negative associations with aging in Chinese Han males older than 50 years, whereas FMI had a positive association. BMD in the femoral neck and total hip declined with age but an increased BMI was protective for BMD. LMI and FFMI were protective for BMD in the femoral neck and total hip.

Abdominal obesity increases the risk of hip fracture. A population-based study of 43,000 women and men aged 60-79 years followed for 8 years. Cohort of Norway

BACKGROUND

The question as to whether abdominal obesity has an adverse effect on hip fracture remains unanswered. The purpose of this study was to investigate the associations of waist circumference, hip circumference, waist-hip ratio, and body mass index with incident hip fracture.

METHODS

The data in this prospective study is based on Cohort of Norway, a population-based cohort established during 1994-2003. Altogether 19,918 women and 23,061 men aged 60-79 years were followed for a median of 8.1 years. Height, weight, waist and hip circumference were measured at baseline using standard procedures. Information on covariates was collected by questionnaires. Hip fractures (n = 1,498 in women, n = 889 in men) were identified from electronic discharge registers from all general hospitals in Norway between 1994 and 2008.

RESULTS

The risk of hip fracture decreased with increasing body mass index, plateauing in obese men. However, higher waist circumference and higher waist-hip ratio were associated with an increased risk of hip fracture after adjustment for body mass index and other potential confounders. Women in the highest tertile of waist circumference had an 86% (95% CI: 51-129%) higher risk of hip fracture compared to the lowest, with a corresponding increased risk in men of 100% (95% CI 53-161%). Lower body mass index combined with abdominal obesity increased the risk of hip fracture considerably, particularly in men.

CONCLUSION

Abdominal obesity was associated with an increased risk of hip fracture when body mass index was taken into account. In view of the increasing prevalence of obesity and the number of older people suffering osteoporotic fractures in Western societies, our findings have important clinical and public health implications.

Associations of fat mass and fat distribution with bone mineral density in Chinese obese population

The purpose of the study was to investigate the associations of fat mass (FM) and fat distribution with bone mineral density (BMD) in Chinese obese population. Three hundred and forty-seven Chinese obese females and 339 males aged 20-39 years were analyzed. Lean mass (LM), FM, percent body fat (%BF), android FM, gynoid FM, and total and regional BMD were measured using dual-energy X-ray absorptiometry. Fat distribution was assessed by android-to-gynoid FM ratio (AOI). As a result, increased central body fat had an inverse association with total and leg BMD in females but not in males. Increased FM and %BF were positively associated with arm, trunk, and pelvic BMD in Chinese obese females. Increased FM was positively associated with total, rib, and trunk BMD in Chinese obese males. The results remained almost unchanged after adjusting for LM, and LM was significantly positively associated with spine BMD in female group. FM was positively associated with trunk BMD in male group after adjusting for LM. AOI was inversely associated with total and leg BMD, and %BF was positively associated with arm, trunk, and pelvic BMD when replacing FM with %BF in female group. The results remained almost unchanged after adjusting for LM. There is no significant association in male group when replacing FM with %BF. In conclusion, our findings demonstrate that there are different associations of FM and fat distribution with BMD, and AOI has a negative association with BMD.

The relationship between body fat and bone mineral density in Korean men and women

Previous studies of the effects of body fat on bone mineral density (BMD) have shown conflicting results depending on the age, sex, and menopausal status of the subjects. The purpose of the present study was to investigate the effects of body fat on BMD using data from the Fifth Korea National Health and Nutrition Examination Survey, which was conducted in 2010. Our data were drawn from a relevant population within the survey's range of participants, yielding a total of 4,138 subjects aged 20-93 years (1,133 men <50 years, 946 men ≥ 50 years, 1,332 premenopausal women, and 727 postmenopausal women). Percent body fat, fat mass (FM), lean mass (LM), and BMD of the total hip, lumbar spine, and arm were measured in the original survey using dual-energy X-ray absorptiometry. Relationships between FM and BMD were evaluated using multiple linear regression analyses. LM was the strongest determinant of BMD. Although FM also showed a significant positive correlation, even after adjusting for LM, with total hip and lumbar spine BMD in men ≥ 50 years and pre- and postmenopausal women, this positive correlation was not observed in the arm. In an analysis of obese and non-obese subgroups, the positive correlation between FM and BMD disappeared in obese subjects. Furthermore, FM and BMD exhibited a negative correlation in premenopausal obese women. These results suggest that FM contributes to BMD primarily through mechanical loading. FM, then, is not beneficial and may be detrimental to bone health in obese people.

Sex-related differences in the association between waist circumference and bone mineral density in a Korean population

Background

Large waist circumference is linked to poor health. Investigations of the relationship between waist circumference, as an index of abdominal fat, and bone mineral density (BMD) have yielded inconsistent results. We investigated the association between abdominal obesity measured using waist circumference and BMD in a large-scale population-based study.

Methods

We enrolled 8981 Korean (3592 males and 5389 females) community-dwelling individuals aged ≥50 years from 2007 to 2010. BMD was measured using dual-energy X-ray absorptiometry at lumbar spine and femoral neck skeletal sites. A multiple linear regression analysis was used to evaluate the relationship between waist circumference quartiles and BMD after adjusting for age, height, weight, and regular exercise.

Results

The adjustment for age, height, weight, and regular exercise revealed a negative linear association between quartile of waist circumference and BMD at the femoral neck and lumbar spine sites in males and females. Waist circumference was more strongly correlated with BMD in males than in females. Although the correlations were slightly attenuated following further adjustment for percent body fat, they remained statistically significant.

Conclusions

Our results revealed that waist circumference is independently and inversely associated with BMD after adjusting for age, weight, height, regular exercise and percent body fat, suggesting that waist circumference is a potential predictor of osteoporosis in middle-aged and older Korean males and females.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2474-15-326) contains supplementary material, which is available to authorized users.

Is the negative relationship between obesity and bone mineral content greater for older women?

Obesity and osteoporosis are two important body composition problems with increasing prevalences in aged populations. Traditionally, obesity has been regarded as being beneficial to bone health. However, the protective effect of obesity on osteoporosis has been questioned. In some recent studies, obesity, as defined by percentage body fat, was regarded as a risk factor for osteoporosis. The purpose of this study was to (1) evaluate the effect of waist circumference, a surrogate measure for abdominal obesity, on bone mineral content (BMC) and (2) examine whether the effect of waist circumference increases with advancing age. The study population is made up of women aged over 45 years who completed the body composition and bone mineral density examinations in the fifth Korea National Health and Nutrition Examination Survey in 2010. Subjects who take estrogen or are under medical treatment for osteoporosis were excluded. Stroke patients are also excluded. Femoral neck, total-hip, and whole-body BMC were measured by dual-energy X-ray absorptiometry. A total of 1,434 subjects were included in the analysis. Waist circumference was negatively associated with BMC in all tested regions after correction for weight, menopausal status, smoking, drinking, and exercise. In addition, the negative association between waist circumference and BMC in the femoral neck and total hip increases with age, after correction for confounding factors, showing an interaction effect between waist circumference and age on BMC. In conclusion, this study shows that the negative relationship between waist circumference and BMC in the femoral neck and total hip is greater for older women.