Lean mass as a determinant of bone mineral density of proximal femur in postmenopausal women

Characteristics of bone mineral density in patients with functional hypothalamic amenorrhoea and its association with reproductive hormones and body composition

OBJECTIVE

Bone mineral density (BMD) is typically reduced in patients with female athlete triad (FAT) and anorexia nervosa (AN). However, bone health in most patients with functional hypothalamic amenorrhoea (FHA), who may not suffer from severe energy deficiency, has not received adequate attention in clinical practice. This study aimed to investigate BMD and its association with clinical and endocrine features in individuals with FHA and to provide clinical evidence for improving bone loss and preventing osteoporosis in FHA.

DESIGN

To assess the bone status of patients with FHA and investigate its association with various clinical and endocrinological characteristics.

PATIENTS

We retrospectively analysed 80 patients with FHA who attended the Obstetrics and Gynecology Hospital of Fudan University from January 2022 to March 2023.

MEASUREMENTS

The levels of reproductive hormones, including luteinising hormone (LH), follicle-stimulating hormone, oestradiol (E2 ) and total testosterone (TT), were examined at the time of initial diagnosis, and a body composition analyser was used to measure body fat percentage (BF%), lean body mass (LBM) and segmental muscle/fat. Dual-emission X-ray absorptiometry was used to measure lumbar spine BMD and femoral neck BMD in patients with FHA, and the Z score was calculated.

RESULTS

The study cohort consisted of 80 female patients with FHA. The average age of the patients was 24.64 ± 6.02 years, and their body mass index (BMI) was 19.47 ± 2.86 kg/m2 . The duration of weight loss was 12 (6, 24) months, while the duration of oligo/amenorrhoea was 12 (4.5, 24) months. The mean degree of weight loss was 18.39 ± 9.53%. Low BMD were present in 15% of patients with FHA at the lumbar spine and/or femoral neck; 12.5% and 10% had low bone mass at the lumbar spine and femoral neck, respectively. The low bone mass group experienced a longer period of weight loss than the normal group [24 (16.5, 60) vs. 12 (4.5, 24) months, p = .037]. In addition, the abnormal group had a lower BMR (basal metabolic rate, BMR) [1158 ± 85 vs. 1231 ± 91 kcal/day, p = .011] and lower bone mineral content [2.15 ± 0.26 vs. 2.43 ± 0.31 kg, p = .009] than the normal group. Both LBMD and femoral neck BMD (Fn BMD) were positively correlated with BMI, BF%, LBM, and regional muscle/fat mass (all p < .05). There was also a positive correlation between LBMD and basal LH levels (p = .009) and waist-to-hip ratio (p = .034), whereas Fn BMD was positively correlated with TT levels (p = .029). Multiple linear regression analysis showed that LBM was positively associated with LBMD (β = .007, 95% confidence interval [CI] = 0.004-0.009, p < .001), while trunk muscle mass was positively associated with Fn BMD (β = .046, 95% CI = 0.013-0.080, p = .008).

CONCLUSION

Fifteen percent of the patients with FHA exhibited low bone mass, a condition associated with prolonged weight loss. The basal LH and TT levels showed positive correlations with LBMD and Fn BMD, respectively. Meanwhile, BMR levels, BMI, BF%, and muscle mass were all positively correlated with LBMD and Fn BMD. Clinically, we should be attentive to suboptimal bone health in patients with FHA and take early screening, diagnosis and intervention measures, especially appropriate muscle mass gain, to prevent the onset of osteoporosis and fragility fractures in the long term.

Association between serum uric acid levels and bone mineral density in patients with osteoporosis: a cross-sectional study

BACKGROUND

The results of studies exploring the association between serum uric acid (SUA) and bone mineral density (BMD) have been controversial and inconsistent. We thus sought to explore whether SUA levels were independently associated with BMD in patients with osteoporosis (OP).

METHODS

This cross-sectional analysis was conducted using prospectively obtained data from the Affiliated Kunshan Hospital of Jiangsu University database pertaining to 1,249 OP patients that were hospitalized from January 2015 - March 2022. BMD was the outcome variable for this study, while baseline SUA levels were the exposure variable. Analyses were adjusted for a range of covariates including age, gender, body mass index (BMI) and a range of other baseline laboratory and clinical findings.

RESULTS

SUA levels and BMD were independently positively associated with one another in OP patients. Following adjustment for age, gender, BMI, blood urae nitrogen (BUN), and 25(OH)D levels, a 0.0286 g/cm² (β, 0.0286; 95% confidence interval [CI], 0.0193-0.0378, P < 0.000001) increase in BMD was observed per 100 μmol/L rise in SUA levels. A non-linear association between SUA and BMD was also observed for patients with a BMI < 24 kg/m², with a SUA level inflection point at 296 μmol/L in the adjusted smoothed curve.

CONCLUSIONS

These analyses revealed SUA levels to be independently positively associated with BMD in OP patients, with an additional non-linear relationship between these two variables being evident for individuals of normal or low body weight. This suggests that SUA levels may exert a protective effect on BMD at concentrations below 296 μmol/L in normal- and low-weight OP patients, whereas SUA levels above this concentration were unrelated to BMD.

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

PURPOSE

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

METHOD

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

RESULTS

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

CONCLUSION

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

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.

Influence of the appendicular skeletal muscle mass index on the bone mineral density of postmenopausal women

BACKGROUND

The appendicular skeletal muscle mass index (ASMI) is an important risk indicator for osteoporosis because of the anatomical proximity and metabolic connection between muscle and bone mass. The present study investigated the relationship between ASMI and the bone mineral density (BMD) categories of postmenopausal women.

METHODS

In this cross-sectional study with a probabilistic sample, sociodemographic, lifestyle, menopause time, anthropometric, and physical activity variables were collected. ASMI and BMD were assessed by dual-energy X-ray absorptiometry (DXA). Participants were grouped according to BMD values into normal density, osteopenia, and osteoporosis. Multivariate logistic regression models were applied to verify the influence of ASMI on BMD. Data were analyzed using the SPSS statistical software, version 22. The significance level for all tests was set at 5%.

RESULTS

Of the 114 women analyzed, most were between 60 and 69.9 years of age (62.3%), on menopause for ≤19.0 (51.8%), self-declared brown race/color (49.1%), had < 4 years of education (41.2%), never smoked (69.0%) or drank alcohol (62.8%). Of these, 52.6% were classified as sufficiently active and 52.2% had regular sun exposure. Women with osteoporosis were older (p = 0.035), on menopause for a longer time (p = 0.011), underweight (p = 0.004), had adequate waist circumference (p = 0.017), and low ASMI values (p = 0.002). There was an association between the 1st tertile of ASMI and osteoporosis. However, after adjustments for age, race/color, and body mass index, the strength of association between BMD and ASMI was not maintained.

CONCLUSIONS

ASMI was not associated with the BMD of the postmenopausal women evaluated. Total body and muscle mass, in addition to bone mass, should be monitored during menopause treatment. Longitudinal studies must be conducted to elucidate the mechanisms and gaps in this relationship.

Association between serum uric acid and bone mineral density in patients with type 2 diabetes: A 6-year longitudinal study in China

The relationship between serum uric acid (UA) and bone mineral density (BMD) has been proposed by several researchers. However, there has been no consensus regarding the relationships among serum UA, diabetes, and BMD. The aim of this study is to investigate the association between UA, BMD, and at least osteopenia in type 2 diabetes patients.This research was a longitudinal study performed at Xiao-Tang-Shan Hospital in Beijing. Type 2 diabetes diagnosis was consistent with the WHO standard classification. Participants with osteopenia or osteoporosis documented by dual-energy X-ray absorptiometry were defined as having "at least osteopenia." A generalized additive model and multivariable logistic regressions were performed to explore the relationship between serum UA and at least osteopenia. Receiver operating characteristic analysis was conducted. Propensity score matching was used to verify the correctness of the cutoff point.In total, 3476 type 2 diabetes patients free of any osteopenia-related diseases were recruited in 2012 and followed up to 2018. The general proportions of patients with at least osteopenia in 2018 was 16.46% (572/3476). Serum UA was negatively associated with BMD stratified by sex, age group, and BMI level. Setting the first quartile as the reference, the risk of at least osteopenia in the fourth quartile was significant among all patients (odds ratio [OR]: 0.75; 95% confidence interval [CI]: 0.57, 0.98) and specifically in females (OR: 0.79; 95% CI: 0.43, 0.97), patients aged over 50 years (OR: 0.79; 95% CI: 0.60, 0.97) and patients with a BMI greater than 25 (OR: 0.74; 95% CI: 0.47, 0.97). The optimal cutoff point for the serum UA level to distinguish at least osteopenia in diabetic patients was 395 μmol/L.Serum UA concentration is negatively associated with the occurrence of at least osteopenia in Chinese patients with type 2 diabetes.

Bone and skeletal muscle changes in oldest-old women: the role of physical inactivity

BACKGROUND

Alterations in bone and muscle parameters related to advanced aging and physical inactivity have never been investigated in oldest-old women.

AIMS

To investigate the impact of physical inactivity on bone mineral density (BMD) and body composition at the systemic and regional levels in oldest-old (> 75 years old) women. We hypothesized that, further to aging, alterations in bone and body composition parameters are exacerbated in the locomotor limbs that have experienced physical inactivity.

METHODS

Whole-body and regional (lower limbs and trunk) BMD and fat-free soft tissue mass (FFSTM) were measured by means of dual-energy X-ray absorptiometry in 11 oldest-old wheelchair-bound women (OIW), 11 oldest-old mobile women (OMW), and 11 young healthy women (YW), all matched for weight (± 10 kg), height (± 10 cm).

RESULTS

Whole-body BMD was reduced by 15% from YW to OMW and 10% from OMW to OIW. Whole-body FFSTM was also reduced from YW to OIW (- 13%). Lower limb BMD was progressively reduced among YW, OMW and OIW (- 23%). Similarly, lower limb FFSTM was reduced among YW (12,816 ± 1797 g), OMW (11,999 ± 1512 g) and OIW (10,037 ± 1489 g). Trunk BMD was progressively reduced among YW, OMW and OIW (- 19%), while FFSTM was similar among the three groups ~ 19801 g.

CONCLUSIONS

The results of the present study suggest that the alterations in bone and body composition parameters are exacerbated in the physical inactive oldest-old. These negative effects of physical inactivity are not confined to the locomotor limbs, and a systemic decline of bone and muscle parameters are likely associated with the physical inactivity.