Body composition and bone mineral density in premenopausal and early perimenopausal women

Trunk-to-leg-volume ratio is not associated with bone density or fracture risk in middle-aged adults: results from the National Health and Nutrition Examination Survey

Unlike a high body mass index or waist circumference, a high trunk-to-leg-volume ratio does not associate with a lower risk of osteopenia/osteoporosis at the femoral neck. While elevated TLVR showed a suggestive association with a history of wrist fracture in women, additional research is needed to confirm this suggestion.

PURPOSE

Body mass index (BMI) and waist circumference (WC) are commonly used to predict bone health, which is typically assessed via bone mineral density (BMD). Trunk-to-leg-volume ratio (TLVR), a relatively novel measure, predicts cardiometabolic outcomes, but its relationships with BMD and fracture remain unstudied. This study evaluated these anthropometric measures' associations with BMD and fracture in Americans aged 40-60 years.

METHODS

Analyses of middle-aged adults from the 2013-2014 to 2017-2018 National Health and Nutrition Examination Survey were conducted. Whole-body, dual-energy X-ray absorptiometry was used to quantify TLVR as well as BMD at the lumbar spine, while a femur-specific scan was used to quantify femoral neck BMD. Fracture history was self-reported. Linear and logistic regression models were constructed with age, diabetes, smoking, race/ethnicity, education, and physical activity as confounding variables.

RESULTS

TLVR was generally not associated with BMD, while WC and BMI showed positive associations with femoral neck BMD. Odds of osteopenia/osteoporosis at the femoral neck were ~ 65-80% lower among participants in the highest tertile of BMI and WC versus the lowest (p < 0.001). There were no statistically significant associations between anthropometric predictors and fracture. Women in tertiles 2 or 3 of TLVR (p = 0.097 and 0.079, respectively) did have 2.66 times the odds of wrist fracture than women in tertile 1, but this was not significant.

CONCLUSION

As shown in previous research, BMI and WC show positive associations with femoral BMD. In contrast, the more novel anthropometric marker TLVR shows no association with femoral BMD, and no clear association with fracture.

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).

The association of dietary acid load (DAL) with estimated skeletal muscle mass and bone mineral content: a cross-sectional study

BACKGROUND & AIMS

Dietary patterns that promote mild metabolic acidosis may have a negative effect on bone and muscle, and a high dietary acid load (DAL) may be detrimental to skeletal muscle mass and bone mineral content. However, the association between skeletal muscle mass and bone mineral content with dietary acid load has not been consistently reported in previous studies. The objective of the study was to evaluate the association of potential renal net acid load (PRAL) and net endogenous acid production (NEAP) with bone mineral content and skeletal muscle mass in pre-menopause women with overweight or obesity in Iran.

METHOD

Three hundred and ninety women with a body mass index (BMI) of 25 were included in this cross-sectional study. We used a validated 147-item semi-quantitative food frequency questionnaire (FFQ) for evaluating the dietary intake. Based on the dietary data, potential renal net acid load (PRAL) and net endogenous acid production (NEAP) were calculated. Muscle mass and bone mineral content were estimated by a bioelectrical impedance analyzer (BIA).

RESULTS

After controlling for potential confounders, we discovered a significant linear relationship between PRAL (β = -0.027, 95%CI = -0.049 to -0.004, P = 0.02) and NEAP (β = -0.05, 95%CI = -0.097 to -0.003, P = 0.03) and skeletal muscle mass index. However, there was no significant difference between SMM and BMC across PRAL and NEAP tertiles.

CONCLUSION

PRAL and NEAP were found to be inversely related to skeletal muscle mass index among overweight/obese women. Further research is required to establish whether this relationship is important for musculoskeletal health in these populations.

Impact of waist circumference on the risk of vertebral fracture: A nationwide cohort study in South Korea

Evidence on the association between abdominal obesity and vertebral fracture (VF) risk is limited. We examined the association of waist circumference (WC) and abdominal obesity with VF risk in 352,095 South Korean participants aged ≥40 years who underwent health checkups between 2009 and 2012. Abdominal obesity was defined by WC ≥90 cm in men and ≥ 85 cm in women according to the Asian-specific WC cutoff for abdominal obesity. Participants were a representative sample cohort of the Korean National Health Insurance System. The hazard ratios (HRs) and 95% CIs of VF development were determined using multivariable Cox proportional hazard regression analysis. During the 5.5 years of follow-up, there were 2030 and 4968 new cases of VF in men and women, respectively. In men, those with abdominal obesity showed an elevated HR (1.11, 95% CI: 1.01-1.23) of incident VF than did those without abdominal obesity. In women, the HRs of VF increased in higher WC groups after adjusting for confounders (P for trend <0.001); the HR decreased in those with WC <75.0 cm (HR: 0.81, 95% CI: 0.75-0.88) and increased in those with WC 85.0-89.9 cm (HR: 1.12, 95% CI: 1.02-1.22), 90.0-94.9 cm (HR: 1.19, 95% CI: 1.08-1.32), and ≥ 95.0 cm (HR: 1.27, 95% CI: 1.12-1.43) compared with those with WC 80.0-84.9 cm. This association persisted after stratification by age in women. WC and abdominal obesity were positively associated with VF risk in women, and abdominal obesity was associated with VF risk even in men. The consideration of WC and controlling abdominal obesity may be helpful in reducing future VF risk.

Effects of Dietary Protein Quantity on Bone Quantity following Weight Loss: A Systematic Review and Meta-analysis

Research supports the hypothesis that higher total protein intake during weight loss promotes retention of lean soft tissue, but the effect of dietary protein quantity on bone mass, a lean hard tissue, is inconsistent. The purpose of this systematic review and meta-analysis was to assess the effect of dietary protein quantity [higher protein (HP): ≥25% of energy from protein or ≥1.0 g · kg body wt-1 · d-1; normal protein (NP): <25% of energy from protein or <1.0 g · kg body wt-1 · d-1] on changes in bone mineral density (BMD) and content (BMC; total body, lumbar spine, total hip, femoral neck) following a prescribed energy restriction. We hypothesized that an HP diet would attenuate the loss of BMD/BMC following weight loss in comparison to an NP diet. Two researchers systematically and independently screened 2366 publications from PubMed, Cochrane, Scopus, CINAHL, and Web of Science Core Collection and extracted data from 34 qualified publications. Inclusion criteria included the following: 1) healthy subjects ≥19 y; 2) a prescribed energy restriction; 3) measurements of total protein intake, BMD, and BMC; and 4) an intervention duration of ≥3 mo. Data from 10 of the 34 publications with 2 groups of different total protein intakes were extracted and used to conduct a random-effects model meta-analysis. A majority of publications (59%) showed a decrease in bone quantity following active weight loss, regardless of total protein intake. Statistically, the loss of total BMD (P = 0.016; weighted mean difference: +0.006 g/cm2; 95% CI: 0, 0.011 g/cm2) and lumbar spine BMD (P = 0.019; weighted mean difference: +0.017 g/cm2; 95% CI: 0.001, 0.033 g/cm2) was attenuated with an HP versus an NP weight-loss diet. However, the clinical significance is questionable given the modest weighted mean difference and study duration. Higher total protein intake does not exacerbate but may attenuate the loss of bone quantity following weight loss.

Association of physical fitness, body composition, cardiometabolic markers and adherence to the Mediterranean diet with bone mineral density in perimenopausal women. The FLAMENCO project

This study aimed to analyse the association of different components of physical fitness, body composition, cardiometabolic markers and the Mediterranean diet with bone mineral density (BMD) in perimenopausal women, and to test which of these components are independently associated with BMD. The sample comprised 197 perimenopausal women (52.6 ± 4.5 years). Physical fitness was assessed with the "Senior Fitness Test" battery and the handgrip strength and Bruce tests. Fat and lean mass and BMD were measured using dual-energy X-ray absorptiometry. We analysed the markers of metabolic syndrome, C-reactive protein, and components of the Mediterranean diet. Handgrip muscle strength (β = 0.212, P = 0.005), body weight (β = 0.244, P = 0.001), BMI (β = 0.180, P = 0.011) and lean mass (β = 0.379, P < 0.001) were positively associated with BMD. No associations were observed between cardiometabolic markers or the Mediterranean diet with BMD (all P > 0.05). When all relevant indicators of BMD were simultaneously considered, lean mass was the only 1 showing an independent association with BMD (β = 0.392, P < 0.001), explaining 14% of the BMD variability. In conclusion, muscle strength might be a marker of BMD in perimenopausal women. However, lean mass was the only factor independently associated with BMD. Future research to determine whether increasing lean mass through specific exercise-based interventions contributes to increasing BMD is warranted.

Associations between body composition and lifestyle factors with bone mineral density according to time since menopause in women from Southern Brazil: a cross-sectional study

BACKGROUND

The aim of this study was to investigate whether body composition, dietary pattern and habitual physical activity are associated with BMD according to time since menopause in women from Southern Brazil with no clinical evidence of disease.

METHODS

99 participants were enrolled and anthropometry, body composition and BMD by dual energy x-ray absorptiometry, rest metabolic rate by indirect calorimetry, dietary pattern by semi quantitative food frequency questionnaire and habitual physical activity by pedometer were performed.

RESULTS

Mean age was 55.2 ± 4.9 years and mean time since menopause was 6.8 ± 1.0 years. Weight, BMI, lean and fat mass and RMR were higher in women with less than 5 years since menopause with normal versus low bone mass. No differences were found in the studied variables between participants with normal or low bone mass and more than 5 years of menopause. Women with > 5 years since menopause had higher prevalence of osteoporosis, as well as lower BMD in all sites when compared to those with less time since menopause. Calories, carbohydrate, protein, fat and micronutrients intake were similar between groups. When the sample was adjusted for time since menopause, the odds ratio (OR) for low bone mass was 5.21 (95% CI 1.57-17.25, P = 0.004) for BMI <25 kg/m(2), for lean mass <37.5 Kg an OR of 4.4 (95% CI 1.64-11.80, P = 0.004, for fat mass <26.0 Kg an OR of 3.39 (95% CI 1.29-8.85, P = 0.010) and for the intake of vitamin A < 700 mcg/day an OR of 3.00 (95% CI 1.13-7.94, P = 0.012). Low meat and eggs intake or low protein intake did not influence the odds ratio for low bone mass.

CONCLUSION

In this cross-sectional study with postmenopausal women with no clinical evidence of disease, time since menopause, low lean and fat mass were associated with low bone mass. Calories and macronutrients intake as well as habitual physical activity did not interfere with BMD, but participants were mostly sedentary. Further studies are needed in order to determine whether the adequate intake of specific food groups and the type of physical activity could attenuate the time since menopause impact on BMD.

Association and relative importance of multiple obesity measures with bone mineral density: the National Health and Nutrition Examination Survey 2005-2006

All obesity measures were positively associated with femoral neck bone mineral density (BMD), but not with lumbar spine BMD. Hip circumference was the most important obesity measure in relation to BMD.

PURPOSE

Multiple measures are used to quantify obesity; different obesity measures have diverse relationship with BMD. Which obesity measure has the most important value in relation to BMD is still poorly understood. We examined the association between multiple obesity measures and BMD and determined the relative importance (RI, percentage of variation) of multiple obesity measures associated with BMD.

METHODS

Data from 5287 men and women aged between 8 and 69 years (mean age = 29 years) in the National Health and Nutrition Examination Survey 2005-2006 were analyzed. Body mass index (BMI), waist circumference, hip circumference, body fat mass (FM) index, total body FM, abdominal FM, and appendicular FM were considered the exposures and femoral neck and lumbar spine BMD the outcomes.

RESULTS

In the multivariable analysis, greater BMI and hip circumference were associated with increased BMD at the lumbar spine and femoral neck (all P < 0.001). The remaining obesity variables were positively associated with increased femoral neck BMD only (all P < 0.001). RI of all obesity measures associated with femoral neck BMD was much greater than that associated with lumbar spine BMD. Moreover, hip circumference had higher RI (19.8 for femoral neck BMD; 7.0 for lumbar spine BMD) than other obesity measures (all RIs ≤14.1 for femoral neck BMD; all RIs ≤3.5 for lumbar spine BMD) in relation to BMD.

CONCLUSIONS

All obesity measures were positively associated with femoral neck BMD, but not with lumbar spine BMD. Hip circumference was the most important obesity measure in relation to BMD.

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.

Bone density in black and white South African women: contribution of ethnicity, body weight and lifestyle

Ethnic differences in bone mineral density (BMD) between healthy adult black and white South African women were studied. Higher BMD was only noted at the femoral sites in black women. Body weight significantly impacted these findings. A lower fracture risk at all skeletal sites cannot be assumed in black South African (SA) women.

PURPOSE

Bone mineral density (BMD) varies amongst women of different ethnicities. African-Americans have higher BMD at all skeletal sites compared with whites. On the African continent, bone density studies suggest site-specific ethnic differences in BMD. To examine the contribution of body weight and lifestyle characteristics to ethnic differences in BMD between adult black and white South African women, we assessed lumbar spine (SBMD), femoral neck (FNBMD) and total femoral BMD (FTBMD) by dual-energy X-ray absorptiometry (DXA) in 184 black and 143 white women aged between 23 and 82 years.

METHODS

BMDs were compared amongst pre- and postmenopausal blacks and whites before and after adjustment for covariates with significant univariate association with BMD. Volumetric bone mineral apparent density (BMAD) of the spine and femoral neck was also calculated to account for ethnic differences in bone size.

RESULTS

Before adjustment, SBMD was lower (p < 0.05), FTBMD similar and FNBMD (p < 0.01) higher in premenopausal black women. Similar SBMD, but significantly higher BMD at the femoral sites (p < 0.01), was noted in postmenopausal blacks compared with whites. Amongst anthropometric measures and lifestyle factors, only adjustment for weight significantly altered these observed ethnic differences in bone density. After adjustment for weight, SBMD remained lower in premenopausal blacks and became lower in young postmenopausal blacks. Weight adjustment eliminated all ethnic differences in proximal femoral BMD measurements, with the exception of FNBMD that remained higher in younger postmenopausal blacks. Before adjustment, calculated SBMAD was similar and FNBMAD consistently higher in blacks in all the menstrual groups. Adjustment for weight did not alter these findings.

CONCLUSION

Most of the observed ethnic difference in BMD was explained by differences in body weight between black and white SA women. The higher femoral BMD in older blacks may explain, the lower hip fracture prevalence in black South African women. The lower SBMD in pre- and postmenopausal black women in this study suggests that factors other than BMD should be considered to explain a lower vertebral fracture prevalence in blacks, if a lower fracture prevalence does indeed exist.

Relationship of body composition with bone mineral density in northern Chinese men by body mass index levels

Osteoporosis and obesity are severe public health problems in an aging society, and as we all know, bone mineral density (BMD) is closely related to fat mass (FM) and fat distribution. However, studies have long focused on pre- or post-menopausal women, and its presence in men has been underestimated. To investigate the differential impact of fat on BMD, we characterized body composition of northern Chinese men and examined the relationship with BMD according to body mass index (BMI) levels.

METHODS

A cross-sectional study was conducted on 502 healthy northern Chinese men aged 20-89 screened from the participants in a community-based osteoporosis prevention study conducted by the Research Center of Qianfoshan Hospital of Shandong University from 2009 to 2010. The qualified subjects were stratified according to BMI levels as normal weight (18.5 ≤ BMI < 24 kg/m(2), n = 137), overweight (24 ≤ BMI < 28 kg/m(2), n = 225), and obesity (BMI ≥ 28 kg/m(2), n = 140). Total body, left femur, lumbar spine BMD and lean mass (LM), FM, percent body fat (%BF) were measured by dual-energy X-ray absorptiometry. Pearson correlation and age-adjusted partial correlation analyses between body composition-related parameters and BMD were performed. Multiple regression analysis was performed to examine the relationship of BMD with LM, FM and %BF.

RESULTS

Height and weight had positive associations with BMD at all sites, although age had negative associations. Of all subjects, LM and FM were positively correlated with BMD at almost sites (P < 0.01). However, when the subjects were divided into normal weight, overweight and obesity, no relations were reflected between FM and BMD. %BF showed negative correlations with BMD at arm and leg (P < 0.01) in overweight, and with BMD at total body, arm, leg, hip (P < 0.01) in obesity. In regression models, both FM and LM showed statistically positively significant relations with total body and regional BMD in all subjects (all P < 0.05). LM was positively correlated with BMD at almost site (all P < 0.05) in groups, while FM had no association. Interestingly, percent body fat (%BF) had negative associations with BMD at total body, arm, leg and total femur in overweight and obesity.

CONCLUSIONS

The relationship between LM and BMD was certain in northern Chinese men while fat-bone relationship was complicated. %BF had a significantly negative association with total body and regional BMD in overweight and obese men.

Dietary fat and fatty acid profile are associated with indices of skeletal muscle mass in women aged 18-79 years

Age-related loss of skeletal muscle mass results in a reduction in metabolically active tissue and has been related to the onset of obesity and sarcopenia. Although the causes of muscle loss are poorly understood, dietary fat has been postulated to have a role in determining protein turnover through an influence on both inflammation and insulin resistance. This study was designed to investigate the cross-sectional relation between dietary fat intake, as dietary percentage of fat energy (PFE) and fatty acid profile, with indices of skeletal muscle mass in the population setting. Body composition [fat-free mass (FFM; in kg)] and the fat-free mass index (FFMI; kg FFM/m(2)) was measured by using dual-energy X-ray absorptiometry in 2689 women aged 18-79 y from the TwinsUK Study and calculated according to quintile of dietary fat (by food-frequency questionnaire) after multivariate adjustment. Positive associations were found between the polyunsaturated-to-saturated fatty acid (SFA) ratio and indices of FFM, and inverse associations were found with PFE, SFAs, monounsaturated fatty acids (MUFAs), and trans fatty acids (TFAs) (all as % of energy). Extreme quintile dietary differences for PFE were -0.6 kg for FFM and -0.28 kg/m(2) for FFMI; for SFAs, MUFAs, and TFAs, these were -0.5 to -0.8 kg for FFM and -0.26 to -0.38 kg/m(2) for FFMI. These associations were of a similar magnitude to the expected decline in muscle mass that occurs over 10 y. To our knowledge, this is the first population-based study to demonstrate an association between a comprehensive range of dietary fat intake and FFM. These findings indicate that a dietary fat profile already associated with cardiovascular disease protection may also be beneficial for conservation of skeletal muscle mass.

Lower resting and total energy expenditure in postmenopausal compared with premenopausal women matched for abdominal obesity

The menopause is accompanied by increased risk of obesity, altered body fat distribution and decreased skeletal muscle mass. The resulting decrease in RMR should be accompanied by a compensatory change in energy balance to avoid weight gain. We aimed to investigate habitual energy intake and expenditure in pre- and postmenopausal women matched for abdominal obesity. We recruited fifty-one healthy Caucasian women, BMI > 18·5 and <35 kg/m(2), aged 35-45 years (premenopausal, n 26) and 55-65 years (postmenopausal, n 25). Energy intake was measured using 3 d diet diaries and dietary fat quality assessed using adipose tissue fatty acid biomarkers. RMR was measured using indirect calorimetry, and total energy expenditure (TEE) and activity energy expenditure using a combined accelerometer and heart rate monitor. Postmenopausal women had lower RMR and TEE and spent significantly less time undertaking moderate exercise than premenopausal women. Postmenopausal women had a tendency for a lower energy intake, and a similar macronutrient intake but a significantly lower adipose tissue n-6:n-3 ratio (24·6 (se 1·6) v. 37·7 (se 3·1); P < 0·001). The main lifestyle determinant of bone mineral density (which was significantly lower in postmenopausal women) was TEE for premenopausal women, and dietary n-6:n-3 ratio for postmenopausal women. The present results suggest that weight maintenance is achieved in the post- compared with premenopausal status through a combination of reduced energy intake and reduced TEE in a regimen that compromises micronutrient intake and has a negative impact on lean tissue mass. However, lower n-6:n-3 fatty acid intake in postmenopausal women is associated with greater bone mineral density.

Dietary fat and fatty acid profile are associated with indices of skeletal muscle mass in women aged 18-79 years

Age-related loss of skeletal muscle mass results in a reduction in metabolically active tissue and has been related to the onset of obesity and sarcopenia. Although the causes of muscle loss are poorly understood, dietary fat has been postulated to have a role in determining protein turnover through an influence on both inflammation and insulin resistance. This study was designed to investigate the cross-sectional relation between dietary fat intake, as dietary percentage of fat energy (PFE) and fatty acid profile, with indices of skeletal muscle mass in the population setting. Body composition [fat-free mass (FFM; in kg)] and the fat-free mass index (FFMI; kg FFM/m(2)) was measured by using dual-energy X-ray absorptiometry in 2689 women aged 18-79 y from the TwinsUK Study and calculated according to quintile of dietary fat (by food-frequency questionnaire) after multivariate adjustment. Positive associations were found between the polyunsaturated-to-saturated fatty acid (SFA) ratio and indices of FFM, and inverse associations were found with PFE, SFAs, monounsaturated fatty acids (MUFAs), and trans fatty acids (TFAs) (all as % of energy). Extreme quintile dietary differences for PFE were -0.6 kg for FFM and -0.28 kg/m(2) for FFMI; for SFAs, MUFAs, and TFAs, these were -0.5 to -0.8 kg for FFM and -0.26 to -0.38 kg/m(2) for FFMI. These associations were of a similar magnitude to the expected decline in muscle mass that occurs over 10 y. To our knowledge, this is the first population-based study to demonstrate an association between a comprehensive range of dietary fat intake and FFM. These findings indicate that a dietary fat profile already associated with cardiovascular disease protection may also be beneficial for conservation of skeletal muscle mass.

The influence of aging on the association between adiposity and bone mineral density in Jordanian postmenopausal women

The objective of this study was to assess the relative association between body weight, body mass index (BMI), lean mass (LM) and fat mass (FM), and bone mineral density (BMD) in a group of Jordanian postmenopausal women and investigate if this possible association changes with age. A total of 3256 patients had dual-energy X-ray absorptiometry (DXA) scan in the period from January 2009 till January 2012 at the Radiology and Nuclear Medicine Department of Jordan University Hospital. Only 584 women met the selection criteria. Age has been recorded, and patients were divided into subgroups according to age. Body weight and height were measured, and BMI was calculated. Body composition (LM, FM, percentage of android fat, and percentage of gynoid fat) was assessed by DXA. BMD of the lumbar spine (L1-L4) and femoral neck was measured by DXA. Weight, BMI, FM, LM, percentage of android fat, and percentage of gynoid fat were positively correlated to BMD at both lumbar spine and femoral neck. However, this correlation disappeared at the age of 70 yr at lumbar spine and 75 yr at femoral neck. This study suggests that both FM and LM are important determinants of BMD in Jordanian postmenopausal women, and this correlation disappears after the age of 70 yr at lumbar spine and 75 yr at femoral neck.

A path model of sarcopenia on bone mass loss in elderly subjects

OBJECTIVE

Aging is associated with decreases in muscle mass, strength, power (sarcopenia) and bone mineral density (BMD). The aims of this study were to investigate in elderly the role of sarcopenia on BMD loss by a path model, including adiposity, inflammation, and malnutrition associations.

METHODS

Body composition and BMD were measured by dual X-ray absorptiometry in 159 elderly subjects (52 male/107 female; mean age 80.3 yrs). Muscle strength was determined with dynamometer. Serum albumin and PCR were also assessed. Structural equations examined the effect of sarcopenia (measured by Relative Skeletal Muscle Mass, Total Muscle Mass, Handgrip, Muscle Quality Score) on osteoporosis (measured by Vertebral and Femoral T-scores) in a latent variable model including adiposity (measured by Total Fat Mass, BMI, Ginoid/Android Fat), inflammation (PCR), and malnutrition (serum albumin).

RESULTS

The sarcopenia assumed a role of moderator in the adiposity-osteoporosis relationship. Specifically, increasing the sarcopenia, the relationship adiposity-osteoporosis (β: -0.58) decrease in intensity. Adiposity also influences sarcopenia (β: -0.18). Malnutrition affects the inflammatory and the adiposity states (β: +0.61, and β: -0.30, respectively), while not influencing the sarcopenia. Thus, adiposity has a role as a mediator of the effect of malnutrition on both sarcopenia and osteoporosis. Malnutrition decreases adiposity; decreasing adiposity, in turn, increase the sarcopenia and osteoporosis.

CONCLUSIONS

This study suggests such as in a group of elderly sarcopenia affects the link between adiposity and BMD, but not have a pure independent effect on osteoporosis.

Nutritional influences on age-related skeletal muscle loss

Age-related muscle loss impacts on whole-body metabolism and leads to frailty and sarcopenia, which are risk factors for fractures and mortality. Although nutrients are integral to muscle metabolism the relationship between nutrition and muscle loss has only been extensively investigated for protein and amino acids. The objective of the present paper is to describe other aspects of nutrition and their association with skeletal muscle mass. Mechanisms for muscle loss relate to imbalance in protein turnover with a number of anabolic pathways of which the mechanistic TOR pathway and the IGF-1–Akt–FoxO pathways are the most characterised. In terms of catabolism the ubiquitin proteasome system, apoptosis, autophagy, inflammation, oxidation and insulin resistance are among the major mechanisms proposed. The limited research associating vitamin D, alcohol, dietary acid–base load, dietary fat and anti-oxidant nutrients with age-related muscle loss is described. Vitamin D may be protective for muscle loss; a more alkalinogenic diet and diets higher in the anti-oxidant nutrients vitamin C and vitamin E may also prevent muscle loss. Although present recommendations for prevention of sarcopenia focus on protein, and to some extent on vitamin D, other aspects of the diet including fruits and vegetables should be considered. Clearly, more research into other aspects of nutrition and their role in prevention of muscle loss is required.

Association between abdominal obesity and fracture risk: a prospective study

CONTEXT

Higher body weight is associated with greater bone mineral density (BMD) and lower fracture risk. However, the relationship between abdominal fat mass (aFM) and fracture risk is unclear because of limited prospective data. The present study sought to examine the association between aFM, BMD, and fracture risk.

METHODS

The study was designed as a prospective investigation, in which a sample of 1126 participants (360 men and 766 women) aged 50 years or older had been continuously followed up for an average of 5 years. The mean age of participants was 71 years (range, 57-94 years). At baseline, BMD at the femoral neck and lumbar spine and aFM were measured by dual-energy X-ray absorptiometry. The incidence of low-trauma and nonpathological fractures was ascertained prospectively from X-ray reports.

RESULTS

During the follow-up period, 19 men and 107 women had sustained a fracture. In women, each 1-kg lower aFM was associated with a 50% higher risk of fracture (hazard ratio [HR], 1.50; 95% confidence interval [CI], 1.10-2.05) after adjustment for age, femoral neck BMD, falls, stature, physical activity, and prior fracture. Subgroup analysis by fracture type found that the association was mainly observed in clinical vertebral fracture (HR, 1.96; 95% CI, 1.22-3.13). In men, although there was no statistically significant association between aFM and fracture risk (HR, 1.15; 95% CI, 0.58-2.25), the strength of this finding is affected negatively by the low number of fractures.

CONCLUSIONS

Lower abdominal fat was significantly associated with an higher fracture risk in women.

A higher alkaline dietary load is associated with greater indexes of skeletal muscle mass in women

Conservation of muscle mass is important for fall and fracture prevention but further understanding of the causes of age-related muscle loss is required. This study found a more alkaline diet was positively associated with muscle mass in women suggesting a role for dietary acid-base load in muscle loss.

INTRODUCTION

Conservation of skeletal muscle is important for preventing falls and fractures but age-related loss of muscle mass occurs even in healthy individuals. However, the mild metabolic acidosis associated with an acidogenic dietary acid-base load could influence loss of muscle mass.

METHODS

We investigated the association between fat-free mass (FFM), percentage FFM (FFM%) and fat-free mass index (FFMI, weight/height²), measured using dual-energy X-ray absorptiometry in 2,689 women aged 18-79 years from the TwinsUK Study, and dietary acid-base load. Body composition was calculated according to quartile of potential renal acid load and adjusted for age, physical activity, misreporting and smoking habit (FFM, FFMI also for fat mass) and additionally with percentage protein.

RESULTS

Fat-free mass was positively associated with a more alkalinogenic dietary load (comparing quartile 1 vs 4: FFM 0.79 kg P < 0.001, FFM% 1.06 % <0.001, FFMI 0.24 kg/m² P = 0.002), and with the ratio of fruits and vegetables to potential acidogenic foods.

CONCLUSIONS

We observed a small but significant positive association between a more alkaline diet and muscle mass indexes in healthy women that was independent of age, physical activity and protein intake equating to a scale of effect between a fifth and one half of the observed relationship with 10 years of age. Although protein is important for maintenance of muscle mass, eating fruits and vegetables that supply adequate amounts of potassium and magnesium are also relevant. The results suggest a potential role for diet in the prevention of muscle loss.

Cold-activated brown adipose tissue is an independent predictor of higher bone mineral density in women

In animals, defective brown adipogenesis leads to bone loss. Whether brown adipose tissue (BAT) mass relates to bone mineral density (BMD) in humans is unclear. We determined the relationship between BAT mass and BMD by cold-stimulated positron-emission tomography (PET) and dual-energy X-ray absorptiometry (DXA) in healthy volunteers. Higher BAT mass was associated with higher BMD in healthy women, but not in men, independent of age and body composition.

INTRODUCTION

Contrary to the traditional belief that BAT is present only in infants, recent studies revealed significant depots of BAT present in adult humans. In animals, defective brown adipogenesis leads to bone loss. While white adipose tissue mass is a known determinant of BMD in humans, the relationship between BAT and BMD in humans is unclear. We thus examined the relationship between BAT and BMD in healthy adults.

METHODS

BAT volume (ml) and activity (standard uptake value) were determined by 18F-fluorodeoxyglucose PET after overnight mild cold exposure at 19 °C, and BMD was determined by DXA.

RESULTS

Among 24 healthy adults (age 28±1 years, F=10), BAT volumes were 82.4±99.5 ml in women and 49.7±54.5 ml in men. Women manifested significantly higher BAT activity, by 9.4±8.1% (p=0.03), than men. BAT volume correlated positively with total and spine BMD (r2=0.40 and 0.49, respectively, p<0.02) in women and remained a significant predictor after adjustment for age, fat, and lean body mass (p<0.05). Total and spine BMD were higher in women who harbored visually detectable BAT on PET images than those without by 11±2% (p=0.02) and 22±2% (p<0.01), respectively. No associations were observed between BAT parameters and BMD in men.

CONCLUSIONS

This study demonstrated higher BMD among healthy women with more abundant BAT, independent of age and other body compositional parameters. This was not observed in men. The data suggest that brown adipogenesis may be physiologically related to modulation of bone density.

Effect of fat mass and lean mass on bone mineral density in postmenopausal and perimenopausal Thai women

BACKGROUND

The purpose of this study was to investigate the association between fat mass, lean mass, and bone mineral density (BMD) in postmenopausal and perimenopausal Thai women.

METHODS

A cross-sectional study was conducted in 1579 healthy Thai women aged 40-90 years. Total body, lumbar spine, total femur, and femoral neck BMD and body composition were measured by dual x-ray absorptiometry. To evaluate the associations between fat mass and lean mass and various measures of BMD, multivariable linear regression models were used to estimate the regression coefficients for fat mass and lean mass, first in separate equations and then with both fat mass and lean mass in the same equation.

RESULTS

Among the study population, 1448 subjects (91.7%) were postmenopausal and 131 (8.3%) were perimenopausal. In postmenopausal women, after controlling for age, height, and duration of menopause, both fat mass and lean mass were positively correlated with BMD when they were analyzed independently of each other. When included in the same equation, both fat mass and lean mass continued to show a positive effect, but lean mass had a significantly greater impact on BMD than fat mass at all regions except for total body. Lean mass but not fat mass had a positive effect on BMD at all skeletal sites except the lumbar spine, after controlling for age and height in perimenopausal women.

CONCLUSION

Lean mass had a significant beneficial effect on BMD in both postmenopausal and perimenopausal women and can be considered as one of the determinants of bone mass. The effect of the fat mass was related to menopausal status, but only demonstrated a positive impact in perimenopausal women.

Bone metabolism in obesity and weight loss

Excess body weight due to obesity has traditionally been considered to have a positive effect on bone; however, more recent findings suggest that bone quality is compromised. Both obesity and caloric restriction increase fracture risk and are regulated by endocrine factors and cytokines that have direct and indirect effects on bone and calcium absorption. Weight reduction will decrease bone mass and mineral density, but this varies by the individual's age, gender, and adiposity. Dietary modifications, exercise, and medications have been shown to attenuate the bone loss associated with weight reduction. Future obesity and weight loss trials would benefit from assessment of key hormones, adipokine and gut peptides that regulate calcium absorption, and bone mineral density and quality by using sensitive techniques in high-risk populations.

The relationship between body composition and bone mineral density in postmenopausal Turkish women

In a retrospective cross-sectional study among 202 postmenopausal women aged 46-75 years, we aimed to investigate the relationship between body composition and bone mineral density (BMD) to determine whether fat mass or lean mass is a better determinant of BMD in Turkish postmenopausal women. Lumbar spine (L1-L4) and proximal femur BMD were measured by dual energy X-ray absorbsiometry. Body composition analysis was performed by bioelectric impedance method and fat mass, lean mass, and percent fat were measured. Both fat mass and lean mass were positively correlated with BMD at the lumbar spine and proximal femur, weight and body mass index. Lean mass was also positively correlated with height and negatively correlated with age and years since menopause (P < 0.01). The correlations of fat mass and lean mass with BMD at the lumbar spine and proximal femur remained significant after adjustment for age, years since menopause and height. When the lean mass was adjusted together with age, years since menopause and height, the significant relationship between the fat mass and BMD continued, however the significant correlation between the lean mass and BMD disappeared at all sites after adjustment for fat mass. In multiple regression analyses, fat mass was the significant determinant of all BMD sites. Our data suggest that fat mass is the significant determinant of BMD at the lumbar spine and proximal femur, and lean mass does not have an impact on BMD when fat mass was taken into account in Turkish postmenopausal women.

Age determines longitudinal changes in body composition better than menopausal and bone status: the OFELY study

Long-term body composition (BC) changes and their determinants have been rarely explored. We aimed to evaluate BC changes in French women from the Os des Femmes de Lyon (OFELY) cohort and to explore several determinants of those changes. At baseline, premenopausal (PreM) women (n = 145) had lower fat body mass (FM) and greater lean body mass (LM), relative skeletal muscle mass index (RASM), and total body bone mineral content (TBBMC) compared with untreated postmenopausal (PostM) women (n = 412). During a 6-year follow-up, LM and RASM did not change, whereas a significant increase of FM and a decrease of TBBMC were observed in PreM (n = 88) and PeriM women (n = 44; women who became PostM during the follow-up). In untreated PostM women, FM increased, whereas LM, RASM, and TBBMC decreased (p < 0.0001). Age was a significant determinant of the changes in BC. After controlling for age, menopausal status was still a significant determinant only for changes in TBBMC. FM, LM, RASM, and TBBMC were higher in women with normal bone mineral density (BMD) compared with women with osteopenia or osteoporosis (p < 0.0001), but after adjusting for age, changes of BC were not significantly different according to the bone status. After controlling for age and menopausal status, levels of P1NP in the highest quartile were associated with a greater decrease of LM and RASM compared with lower levels. In conclusion, BC changes in French women over a 6-year follow-up showed a high interindividual variability. Aging may be the most important determinant of changes in body composition, rather than menopausal and bone status.

Body composition in ambulatory patients with multiple sclerosis

The aim of this study was to compare between ambulatory patients with multiple sclerosis (MS) and control subjects, bone mineral density (BMD), and body composition, that is, percent of bone minerals (M%), fat (F%), and remaining substances (L%). Total body composition and BMD were measured by dual-energy X-ray absorptiometry in 68 patients with definite MS and Expanded Disability Status Scale (EDSS) score ≤ 6.5 (41 females and 27 males) and 114 control individuals (72 females and 42 males). The amount of F%, L%, M%, and BMD in the whole body, arms, and trunk was not statistically different between MS patients (males and females) and controls, except in the lower extremities of female patients where there was increased F% and reduced L% compared with controls. There were no correlations between F%, L%, M%, and BMD at any anatomic region with EDSS or the cumulative corticosteroid dose. The reduced L% in the lower extremities of female patients suggests a possible increased subsequent risk of osteoporosis in the legs. Brief steroid courses administered during disease exacerbations in ambulatory MS patients did not result in obvious adverse consequences.

Contributions of lean mass and fat mass to bone mineral density: a study in postmenopausal women

Background

The relative contribution of lean and fat to the determination of bone mineral density (BMD) in postmenopausal women is a contentious issue. The present study was undertaken to test the hypothesis that lean mass is a better determinant of BMD than fat mass.

Methods

This cross-sectional study involved 210 postmenopausal women of Vietnamese background, aged between 50 and 85 years, who were randomly sampled from various districts in Ho Chi Minh City (Vietnam). Whole body scans, femoral neck, and lumbar spine BMD were measured by DXA (QDR 4500, Hologic Inc., Waltham, MA). Lean mass (LM) and fat mass (FM) were derived from the whole body scan. Furthermore, lean mass index (LMi) and fat mass index (FMi) were calculated as ratio of LM or FM to body height in metre squared (m²).

Results

In multiple linear regression analysis, both LM and FM were independent and significant predictors of BMD at the spine and femoral neck. Age, lean mass and fat mass collectively explained 33% variance of lumbar spine and 38% variance of femoral neck BMD. Replacing LM and FM by LMi and LMi did not alter the result. In both analyses, the influence of LM or LMi was greater than FM and FMi. Simulation analysis suggested that a study with 1000 individuals has a 78% chance of finding the significant effects of both LM and FM, and a 22% chance of finding LM alone significant, and zero chance of finding the effect of fat mass alone.

Conclusions

These data suggest that both lean mass and fat mass are important determinants of BMD. For a given body size -- measured either by lean mass or height --women with greater fat mass have greater BMD.

Relation between body mass index and bone mineral density among haemodialysis patients with chronic kidney disease

Renal osteodystrophy is a serious problem for patients with chronic kidney disease. Measurements of bone mineral density, T-score and Z-score were taken in the lumbar region and femur of 73 patients who were being treated on the haemodialysis programme. These measurements were compared with the anthropometric values of weight, height and body mass index (BMI) obtaining a positive correlation between them.

INTRODUCTION

Alterations in the bone mineral metabolism are an important cause of morbidity and mortality among haemodialysis patients with chronic renal failure. Bone mass diminution, together with fracture risk, is a frequent finding in these patients; this fact is explained by different factors, amongst which are those related to their anthropometric values.

MATERIALS AND METHODS

Bone mineral density (BMD) was studied, T-score and Z-score measurements were taken in the neck of the femur, trochanter, intertrochanter, 1/3 of proximal femur, Ward's triangle and L2, L3 and L4 vertebrae; body composition was also studied. With this aim, DXA densitometry was used on 73 haemodialysis patients (40 men and 33 women). The mean of the total haemodialysis time in these patients was 9.7 years. The group showed a very significant positive correlation between BMD, weight, height, BMI, fractures, dialysis time and intact PTH.

CONCLUSIONS

CKD patients undergoing the haemodialysis programme show a significant BMD reduction, which affects both lumbar spine and femur. Weight and height affect BMD and bone change, being thus important factors of prediction for fracture risk. Furthermore, BMI is the main determinant of BMD, a finding that is confirmed in the units in this study and with the evidence described by other authors (Negri et al. (2005).

Effect of body fat stores on total and regional bone mineral density in perimenopausal Chinese women

Accumulation of body fat is known to be beneficial to bone mass through increased body weight. However, not all the skeleton is loaded by body weight. Therefore, we assume that fat stores would exert different effects on bone mass at different skeletal sites. In this study, 84 perimenopausal Chinese women were recruited. Using dual-energy X-ray absorptiometry, total body fat mass (TBFM), total body lean mass (TBLM), percent body fat (PBF), and total body and regional bone mineral density (BMD) were measured. Correlation analysis indicated that PBF correlated negatively with BMD at ribs and both arms (all P < 0.05). After adjusting for TBLM, PBF had a significantly negative correlation with BMD at head, ribs, both arms, and whole body (all P < 0.05). With adjustment for body weight and height, a significantly negative correlation between PBF and BMD was present, not only at ribs and arms but also at legs and whole body (all P < 0.05, except right leg, at P = 0.094). There was a significantly positive correlation between body weight and leg BMD (all P < 0.001). Body weight was positively correlated with TBFM (r (2) = 0.783, P < 0.001) and TBLM (r (2) = 0.770, P < 0.001). Based on the results, we conclude that increased body fat stores would exert a detrimental effect on BMD, but this effect is more prominent on non-weight-bearing bone. On weight-bearing bone, the detrimental effect of increased body fat could be offset or outweighed by the beneficial effect of increased body weight.

Adiponectin is a predictor of bone mineral density in middle-aged premenopausal women

Adipose-modulated biochemical signal that explains some of the association between fat mass and bone mineral density (BMD) is adiponectin. The results demonstrated an independent association between adiponectin and BMD, while the influence of adiponectin on bone mineral content is mediated by fat free mass in middle-aged women.

INTRODUCTION

Positive association between fat mass (FM) and bone mineral density (BMD) is mediated by biochemical factors.

METHODS

The relationship between plasma adiponectin concentration and BMD in 98 sedentary premenopausal women aged 38-49 years with a body mass index range of 20.0-42.1 kg/m(2) was examined. Different body composition and blood biochemical parameters were measured to adjust for possible confounding variables.

RESULTS

The association between adiponectin and BMD values (total BMD: beta = -0.919; p = 0.0001, femoral neck BMD: beta = -0.925; p = 0.0001 and lumbar spine BMD: ss = -0.912; p = 0.0001) was independent of the influences that measured body composition, hormonal and insulin resistance factors may exert on BMD (p < 0.02). However, adiponectin explained only 3-12% of the variations in measured BMD variables. Similarly, adiponectin was associated with total bone mineral content (BMC; beta = -0.911; p = 0.0001) and remained associated in different analyses that controlled for possible confounding parameters (p < 0.01). However, the association between adiponectin and total BMC was no longer significant when adjusted for fat free mass (FFM; p > 0.21).

CONCLUSIONS

Adiponectin is an independent predictor of BMD, while its independent contribution to the interindividual variance in measured values is only modest. The influence of adiponectin on total BMC is mediated or confounded by FFM in middle-aged premenopausal women.

Change in lean body mass is a major determinant of change in areal bone mineral density of the proximal femur: a 12-year observational study

Our objective was to assess the contribution of lean body mass (LBM) and fat body mass (FBM) to areal bone mineral density (aBMD) in women during the years surrounding menopause. We used a 12-year observational design. Participants included 75 Caucasian women who were premenopausal, 53 of whom were available for follow-up. There were two measurement periods: baseline and 12-year follow-up. At both measurement periods, bone mineral content and aBMD of the proximal femur, posterior-anterior lumbar spine, and total body was assessed using dual-energy X-ray absorptiometry (DXA). LBM and FBM were derived from the total-body scans. General health, including current menopausal status, hormone replace therapy use, medication use, and physical activity, was assessed by questionnaires. At the end of the study, 44% of the women were postmenopausal. After controlling for baseline aBMD, current menopausal status, and current hormone replacement therapy, we found that change in LBM was independently associated with change in aBMD of the proximal femur (P = 0.001). The cross-sectional analyses also indicated that LBM was a significant determinant of aBMD of all three DXA-scanned sites at both baseline and follow-up. These novel longitudinal data highlight the important contribution of LBM to the maintenance of proximal femur bone mass at a key time in women's life span, the years surrounding menopause.

Difference in the relative contribution of lean and fat mass components to bone mineral density with generation

AIM

To investigate whether the relative contribution of body composition (lean and fat mass component) to bone mineral density (BMD) differs depending on generation or menopause.

METHODS

Subjects were 302 premenopausal women aged 30-49 years old and 197 postmenopausal women aged 50-69 years old. They were classified into four subgroups with 10-year increments. Age, height, weight and years since menopause (YSM) were recorded. Lumbar spine (L2-4), total body BMD, body fat mass, lean body mass (LBM), and the percentage of body fat (%fat) were measured using dual-energy X-ray absorptiometry. The correlation of body composition with BMD was investigated.

RESULTS

The mean age at menopause was 50.2 +/- 4.1 years old. On Pearson's correlation test, LBM was positively correlated with BMD of the two sites in all groups. In a group aged 60-69 years, both the %fat and body fat mass were correlated with BMD. On multiple regression analysis, LBM was the principal BMD determinant in women aged less than 60 years, while body fat mass and percentage fat were the principal BMD determinants in women aged 60-69 years. Mean %fat in the group aged 60-69 years was 35.5 +/- 7.3%, which was significantly higher than that in the group aged 50-59 years (33.0 +/- 6.7%, P < 0.05).

CONCLUSION

Although LBM still influences BMD up to 10 years after menopause, the body fat mass initially influences BMD after 60 years of age. These difference may be attributable to certain aging-related factor(s).

[Obesity and osteoporosis]

Atherosclerosis is a chronic inflammatory disease associated with an elevation of inflammatory markers such as CRP -- a robust predictor of cardiovascular events. Inflammation also plays a pivotal role in the pathogenesis of osteoporosis. IL-6 proved to be the most important predictor of bone loss in the proximal femur. Adipocyte-produced inflammatory cytokines are the pathogenetic link between obesity and its metabolic consequences. The different components of the metabolic syndrome are at the same time well-established risk factors for osteoporosis. Physical training, weight loss, and a Mediterranean-style diet all have a proven cytokine-lowering effect. Contrary to muscle mass, adipose tissue if at all contributes only marginally to the preservation of bone. As a consequence, increasing lean body mass while reducing fat mass seems to be the most effective way to prevent both atherosclerosis and osteoporosis.

Determinants of peak bone mineral density and bone area in young women

Osteoporosis is a disease caused by compromised bone strength, and individuals with a high peak bone mass at a young age are likely to have a high bone mass in old age. To identify the clinical determinants of peak bone mass in young adult women, 418 southern Chinese women, aged 20-39 years, were studied. Low bone mass was defined as areal bone mineral density (aBMD) Z-score < -1 at either the spine or total hip. Within the cohort, 62 (19.0%) and 86 (26.4%) women had low aBMD at the spine and hip, respectively. Regression model analysis revealed that low body weight (<44 kg) was associated with an 8.3-fold (95% CI, 3.7-18.9) and a 6.8-fold (95% CI, 3.0-15.6) risk of having low aBMD at the spine and hip, respectively. Low body weight was also predictive of low volumetric BMD (vBMD) at the spine (odds ratio (OR) 7.8, 95% CI, 3.1-20.1) and femoral neck (OR 3.0, 95% CI, 1.3-7.1). A body height below 153 cm was associated with a 4.8-fold risk in the small L2-4 bone area (95% CI, 2.3-9.8) and a 3.9-fold risk in the small femoral neck area (95% CI, 1.9-8.1). Delayed puberty (onset of menstruation beyond 14 years) was associated with a 2.2-fold (95% CI, 1.0-4.9) increased risk of having low aBMD at the hip. Physical inactivity was associated with a 2.8-fold risk of low spine vBMD (OR 2.8, 95% CI, 1.1-6.7) and a 3.3-fold risk of low hip aBMD (95% CI, 1.0-10.0). Pregnancy protected against low spine aBMD (OR 0.4, 95% CI, 0.1-1.2) and spine vBMD (OR 0.1, 95% CI, 0.0-1.0), low femoral neck vBMD (OR 0.3, 95% CI, 0.1-1.1) and small L2-4 bone area vBMD (OR 0.3, 95% CI, 0.1-1.1). In conclusion, this study identified a number of modifiable determinants of low peak bone mass in young adult women. Maintaining an ideal body weight, engaging in an active lifestyle, and diagnosing late menarche may enable young women to maximize their peak bone mass and so reduce their risk of osteoporosis in later life.

Bone mineral density by age, gender, pubertal stages, and socioeconomic status in healthy Lebanese children and adolescents

Gender, ethnicity, and lifestyle factors affect bone mass acquisition during childhood, thus the need for age- and sex-adjusted Z scores using ethnic-specific data for bone mineral density (BMD) measurement. This study aimed at establishing normative data for BMD in healthy Lebanese children and adolescents. Three hundred sixty-three healthy children aged 10 to 17 years (mean+/-SD: 13.1+/-2.0) were studied. BMD, bone mineral content (BMC), and lean mass were measured by dual-energy X-ray absorptiometry (DXA) using a Hologic 4500A device, and apparent volumetric BMD (BMAD) of the lumbar spine and the femoral neck were calculated. BMD, BMC, and BMAD were expressed by age groups and Tanner stages for boys and girls separately. There was a significant effect of age and puberty on all bone parameters, except at the femoral neck BMAD in boys. BMC and BMD were higher at cortical sites in boys, including subtotal body and hip; whereas, in girls, it was higher at a site more enriched in trabecular bone, namely the lumbar spine. At several skeletal sites, girls had significantly higher BMD adjusted for lean mass than boys. By the end of puberty, adolescents had a mean BMD that was 43-66% higher at the lumbar spine and 25-41% higher at cortical sites than pre-pubertal children, depending on the gender. Mean BMD values in the study group were significantly lower (P<0.01) than Western normative values, with Z scores ranging between -0.2 and -1.1. In both genders, children of lower socioeconomic status tended to have lower BMD than those from a higher socioeconomic background. This study allows additional insight into gender dimorphism in mineral accretion during puberty. It also provides a valuable reference database for the assessment of BMD in children with pubertal or growth disorders who are of Middle Eastern origin.

Sex differences in the effect of body-composition variables on bone mass in healthy children and adolescents

BACKGROUND

Prophylactic interventions against osteoporosis require a determination of the factors that influence the accumulation of bone mass during growth.

OBJECTIVE

The objective was to determine the independent sex-specific contribution of lean mass and fat mass to bone mineral content (BMC), after adjustment for anthropometric variables and lifestyle factors, in healthy children and adolescents.

DESIGN

Healthy schoolchildren (184 boys and 179 girls) aged 10-17 y (x+/- SD: 13.0 +/- 2.1 y) participated in this cross-sectional study. Total and regional (lumbar spine, femoral neck, and distal one-third of the radius) BMC and body composition were measured by dual-energy X-ray absorptiometry.

RESULTS

A significant effect of anthropometric variables and lifestyle factors on BMC was observed at all skeletal sites. Lean mass and fat mass showed robust correlations with BMC, even after adjustment for anthropometric variables and lifestyle factors. Lean mass contributed to 6-12% of the variance in BMC in boys and to 4-10% in girls. Fat mass accounted for 0.1-2% of BMC variance in boys and to 0.1-6.5% in girls.

CONCLUSIONS

Both lean mass and fat mass are consistent predictors of BMC at multiple skeletal sites in healthy children and adolescents. The contribution of lean mass to BMC variance was larger in boys than in girls. In both sexes, the highest contribution of lean mass to BMC was observed at the femoral neck.

A DXA study of muscle-bone relationships in the whole body and limbs of 2512 normal men and pre- and post-menopausal women

A whole-body DXA study of 1450 healthy Caucasian individuals [Bone 22 (1998) 683] found that mineral mass, either crude (BMC) or statistically adjusted to fat mass (FM-adjusted BMC), correlated linearly with lean mass (LM, proportional to muscle mass). The results showed similar slopes but decreasing intercepts (ordinate values) in the order: pre-MP women > men > post-MP women > children. This supports the hypothesis that sex hormones influence the control of bone status by muscle strength in all species. Now we further study those relationships in 2512 healthy Hispanic adults (307 men, 753 pre-MP women, 1452 post-MP women), including separate determinations in their upper and lower limbs. The slopes of the BMC or FM-adjusted BMC vs. LM relationships were parallel in all the studied regions. However, region-related differences were found between the ordinates of the curves. In the whole body, the crude-BMC/LM relationships showed the same ordinate differences as previously observed. In the lower limbs, those differences were smaller in magnitude but highly significant, showing the order: pre-MP women > men = post-MP women. In the upper limbs, the decreasing ordinate order was: men > pre-MP women > post-MP women. After fat adjustment of the BMC, order in both limbs was: men > pre-MP women > post-MP women. Parallelism of the curves was maintained in all cases. LM had a larger independent influence on these results than FM, body weight, or age. The parallelism of the curves supports the idea that a common biomechanical control of bones by muscles occurs in humans. Results suggest that sex-hormone-associated differences in DXA-assessed muscle-bone proportionality in humans could vary according to the region studied. This could be related to the different weight-bearing nature of the musculoskeletal structures studied. Besides the obvious anthropometric associations, FM would exert a mechanical effect as a component of body weight, evident in the lower limbs, while muscle contractions would induce a more significant, dynamical effect in both lower and upper limbs. Muscles seem to exert a larger influence than FM, body weight, and age on BMC in the whole body and lower limbs, regardless of the gender and reproductive status of the individual. The muscle-bone relationships studied may provide a rationale for a future differential diagnosis between disuse-related and other types of osteopenia.

Influence of weight and weight change on bone loss in perimenopausal and early postmenopausal Scottish women

Weight is recognized as an important factor in determining an individual's risk of osteoporosis. However, little is known about whether weight or weight change influences bone loss around the time of the menopause, and the relationship with energy intake and physical activity level remains largely undefined. Healthy premenopausal women (1,064 selected from a random population of 5,119 women aged 45-54 years at baseline) each had bone mineral density (BMD), weight and height measurements, and completed a food frequency and physical activity questionnaire. Of the original participants, 907 women (85.2%) returned 6.3 +/- 0.6 years later for repeat BMD measurements, and 896 women completed the questionnaires. Bone loss at the hip (FN) and spine (LS) occurred before the menopause. Weight change rather than weight was associated with FN BMD loss (r=0.102, p=0.002), but weight at follow-up was associated with LS BMD change (r=0.105, p=0.002). Although an increase in physical activity level (PAL) appeared to be beneficial for FN BMD in women who were heavy weight gainers, PAL was associated with increased LS BMD loss in women who lost weight. For current HRT users, neither weight nor weight change was associated with change in BMD. Postmenopausal women not taking HRT should be made aware that low body weight or losing weight during this particularly vulnerable period may worsen bone loss.

Lean body mass and bone mineral density in physically exercising postmenopausal women

OBJECTIVES

To investigate whether the relative contribution of body composition (lean and fat mass component) to postmenopausal bone mineral density (BMD) differs between women participating in physical exercise and sedentary women.

METHODS

Subjects were 45 postmenopausal women participating in regular physical exercise and 89 sedentary controls aged 50-60 years. Baseline characteristics included age, height, weight, body mass index (BMI, Wt/Ht(2)), age at menopause, and years since menopause (YSM). Body fat mass, percentage of body fat, lean body mass, and lumbar spine BMD (L2-4) were measured by dual-energy X-ray absorptiometry.

RESULTS

Although age, height, weight, BMI, and YSM did not differ between the two groups, lean body mass and lumbar spine BMD were significantly higher (P<0.05 and <0.001, respectively), while body fat mass and percentage of body fat mass were significantly lower in exercising women than in sedentary controls (P<0.05 and <0.05, respectively). In exercising women, BMD was positively correlated with lean body mass (r=0.415, P<0.01) but not with body fat mass (r=0.155, NS). Conversely, in sedentary controls, BMD was correlated with body fat mass (r=0.251, P<0.05) and lean body mass (r=0.228, P<0.05).

CONCLUSIONS

Lean body mass is a more significant determinant of postmenopausal BMD in physically exercising women than in sedentary women.

Hormone replacement therapy dissociates fat mass and bone mass, and tends to reduce weight gain in early postmenopausal women: a randomized controlled 5-year clinical trial of the Danish Osteoporosis Prevention Study

The aim of this study was to study the influence of hormone replacement therapy (HRT) on weight changes, body composition, and bone mass in early postmenopausal women in a partly randomized comprehensive cohort study design. A total of 2016 women ages 45-58 years from 3 months to 2 years past last menstrual bleeding were included. One thousand were randomly assigned to HRT or no HRT in an open trial, whereas the others were allocated according to their preferences. All were followed for 5 years for body weight, bone mass, and body composition measurements. Body weight increased less over the 5 years in women randomized to HRT (1.94 +/- 4.86 kg) than in women randomized to no HRT (2.57 +/- 4.63, p = 0.046). A similar pattern was seen in the group receiving HRT or not by their own choice. The smaller weight gain in women on HRT was almost entirely caused by a lesser gain in fat. The main determinant of the weight gain was a decline in physical fitness. Women opting for HRT had a significantly lower body weight at inclusion than the other participants, but the results in the self-selected part of the study followed the pattern found in the randomized part. The change in fat mass was the strongest predictor of bone changes in untreated women, whereas the change in lean body mass was the strongest predictor when HRT was given. Body weight increases after the menopause. The gain in weight is related to a decrease in working capacity. HRT is associated with a smaller increase in fat mass after menopause. Fat gain protects against bone loss in untreated women but not in HRT-treated women. The data suggest that women's attitudes to HRT are more positive if they have low body weight, but there is no evidence that the conclusions in this study are skewed by selection bias.

Difference in the effects of body composition on bone mineral density between pre- and postmenopausal women

OBJECTIVE

This study was to investigate whether the effect of lean and fat mass component on bone mineral density (BMD) differs between pre- and postmenopausal women.

MATERIALS AND METHODS

Subjects were 360 pre- and 193 postmenopausal Japanese women with right side dominance. Age, height, and years since menopause (YSM, in postmenopausal women) were recorded. Body fat and lean body mass were measured by whole body scanning with dual-energy X-ray absorptiometry (DEXA). BMD of the vertical axis (L2-4 of the lumbar spine, pelvis, bilateral legs, and total body) and horizontal axis (arms) were also measured by DEXA.

RESULTS

In premenopausal women, lean body mass was independently correlated with BMD of the left arm (partial correlation coefficient = 0.417), right arm (0.430), L2-4 (0.285), pelvis (0.276), left leg (0.403), right leg (0.412), and total body (0.377) (P < 0.001). However, body fat mass was not correlated with several BMD sites except for pelvis BMD (0.187, P < 0.01). In postmenopausal women, body fat mass was independently correlated with BMD of the left arm (0.248, P < 0.01), L2-4 (0.188, P < 0.05), pelvis (0.263, P < 0.01), left leg (0.228, P < 0.01), right leg (0.319, P < 0.001), and total body (0.188, P < 0.01)). However, lean body mass was correlated with BMD in only three segmental regions including left arm (0.175), right arm (0.217), and left leg (0.210; P < 0.05).

CONCLUSION

Lean body mass is a significant determinant of BMD in premenopausal women, while body fat mass is a significant determinant in postmenopausal women.

Instability and variability of urinary telopeptides and free crosslinks

BACKGROUND

The use of the urinary bone degradation markers, NTx and free Dpd, in the diagnosis and monitoring of pathological bone resorption has been studied intensely. Urinary NTx and Dpd are normalized by creatinine to account for differences in diuresis.

METHODS

We investigated the effects of storage (-20 degrees C for 119 days) on concentrations of NTx, Dpd and creatinine in the urine of 40 subjects. Precipitates (visible upon thawing) were resuspended, but specimens were not recentrifuged (in contrast to previous experiments).

RESULTS

After storage at -20 degrees C, the NTx and creatinine concentrations in urine specimens were significantly decreased by about 18% and 22% (p < 0.01 and p < 0.0001), respectively. Thus, the quotient of NTx/creatinine was slightly increased after storage (p < 0.05). Free Dpd and free Dpd/creatinine were both significantly increased after storage (p < 0.0001)--by about 20% and 60%, respectively.

CONCLUSIONS

We suggest that storage at -20 degrees C frees Dpd and denatures the epitope used in NTx quantification, and that these changes are usually masked by the removal of free Dpd via recentrifugation and by the decrease in creatinine in NTx/creatinine. Additionally, we suggest that the quotient Dpd/NTx should be evaluated as an alternative to normalizing via creatinine excretion.

Body composition characteristics are associated with the bone density of the proximal femur end in middle- and old-aged women and men

OBJECTIVES

In the present study the associations between bone density of the proximal femur end and weight status, fat distribution patterns (FDI) and body composition parameters i.e. amount of body fat and lean body mass were tested in a sample of old aged women and men.

METHODS

In 77 healthy women ranging in age from 60 to 92 years (x=71.8 years) and 62 healthy men ranging in age from 60 to 86 years (x=71.5 years) the bone mineral density (BMD of the proximal femur end and the body composition parameters absolute fat mass, relative fat mass, lean body mass and bone mineral content were estimated by dual energy X-ray absorptiometry. Additionally, the weight status (body mass index, BMI) and the FDI were calculated. The bone density of the proximal femur end was correlated with the absolute fat mass and the lean body mass as well as with the BMI and the FDI.

RESULTS

BMD correlated in females significantly positively with parameters of body composition, in males no significant correlations between fat mass (absolute and relative) and BMD as well as BMD/stature was found. Furthermore, it was shown that the weight status (BMI; r(2)=0.13, P<0.0003 in males and r(2)=0.27, P<0.000 in females), and the lean body mass (r(2)=0.21, P<0.001 in males, r(2)=0.36, P<0.004 in females) were associated significantly positively with the BMD of the proximal femur end in both sexes. The absolute fat mass had a significant impact on BMD in the female subsample only (r(2)=0.24, P<0.000).

CONCLUSIONS

A lower weight status and a low amount of lean body mass, indicating not only lack of biomechanical forces of the proximal femur end, but also a lack of physical activity can be assumed to be associated increased bone loss and the development of osteoporosis in both sexes. An association between low amount of fat tissue and decreased BMD was especially found in women and may be due to the reduced conversion rates from androgens to estrogens in a low amount of fat tissue.

Relationship between total and regional bone mineral density and menopausal state, body composition and life style factors in overweight Japanese women

OBJECTIVE

To investigate whether menopausal state, body composition and lifestyle factors influence total and regional bone mineral density in overweight Japanese women.

DESIGN

Cross-sectional study of women who were recruited to the weight reduction program held at community-based health promotion center in Tokyo area.

SUBJECTS

A total of 178 women with a mean age of 48 y old (20-69 y) with a clear menstrual history and BMI over 24.

MEASUREMENTS

Total, regional and lumbar spine bone mineral density (BMD) and body composition were measured using DXA (Lunar). Menstrual history was taken by a questionnaire and walking steps per day and energy intake were measured. Physical fitness was assessed by cardio-respiratory fitness and leg extension power. Subjects were divided into pre-menopausal and post-menopausal groups.

RESULTS

Pre-menopausal group had significantly higher total body BMD as well as regional BMD than post-menopausal group. However, no differences in BMI, percentage fat and fat mass (FM) were seen between the two groups. The multiple regression analysis stepwise method revealed that total and regional BMD correlated with menopausal state and total FM independently. Total and regional BMD did not correlate with total non-fat soft tissue mass (NFSM), energy intake, walking steps or physical fitness levels. Trunk and lower extremities BMD correlated with corresponding regional FM and NFSM, and upper extremities BMD correlated with only corresponding body part NFSM after adjusting menopausal state.

CONCLUSION

Total and regional BMD had strong negative correlation with menopausal state rather than total FM in overweight Japanese women. Weight-bearing site BMD correlated with corresponding body part FM and NFSM and non-weight bearing site BMD only correlated with corresponding body part NFSM after adjusting for menopausal state.

Correlations between biochemical markers of bone resorption and creatinine excretion

There were two reasons for doing this study. The first was to assess whether expressing biochemical markers of bone resorption as a ratio to creatinine excretion influences the correlations between them. The second was to assess whether biochemical markers of bone resorption are correlated with creatinine excretion, which is a biomarker of muscle mass. Three biochemical markers of bone resorption, free deoxypyridinoline (DPD), N-telopeptides (NTx) and C-telopeptides (CTx), together with creatinine (cr), were measured in 24-h urine samples of 45 healthy people (26 women and 19 men). The urinary concentrations of DPD, NTx and CTx were highly correlated with each other. These relationships were weakened, or no longer statistically significant, when the markers were expressed as a ratio to cr excretion. The 24-h excretion of each of the markers was correlated with 24-h cr excretion in men, but only 24-h DPD was correlated with 24-h cr excretion in the women. The men had significantly higher 24-h excretion rates of each of the markers than the women did. Since muscle mass is related to skeletal mass, these data suggest that in healthy people the rate of bone resorption may be a function of skeletal size as well as the rate of bone turnover. For small human studies 24-h urine sampling is recommended in preference to untimed sampling. However, for clinical purposes, or for large clinical trials, this may not be practical.

Body composition predicts bone mineral density and balance in premenopausal women

Low bone mineral density (BMD) and poor stability both contribute to increased risk of fractures associated with a fall. Our aim in this cross-sectional study was to determine the anthropometric and/or performance variables that best predicted BMD and stability in women. BMD, body composition, muscle strength, muscle power, and dynamic stability were evaluated in 61 women (age 40 +/- 4 years; % body fat 27% +/- 5%). In correlation analyses, BMD at all sites was significantly related to height, lean mass, strength, and leg power (r2 = 0.25-0.49). Significant inverse relationships were found between all independent variables and dynamic stability (r2 = 0.23-0.52). In stepwise regression, lean mass independently predicted BMD at the femoral neck (R2 = 0.20), total hip (R2 = 0.24), and whole body (R2 = 0.17), whereas hip abductor torque predicted 23% of the variance in trochanter BMD and added 6% to the variance in total hip BMD. Leg power was the only predictor of spine BMD (R2 = 0.14). Fat and lean mass both independently predicted poor performance on postural stability, with fat mass contributing 31% of the total variance (R2 = 0.38). In conclusion, we found lean mass to be a robust predictor of BMD in premenopausal women. Furthermore, both hip abductor torque and leg power independently predicted BMD at clinically relevant fracture sites (hip and spine). The finding that higher fat mass contributes to the majority of the variance in poor stability indicates that greater fat mass may compromise stability and, thus, increase fall risk in heavier individuals.