The Associations of Body Composition and Fat Distribution With Bone Mineral Density in Elderly Italian Men and Women

This study aimed to investigate the associations of body composition and fat distribution with bone mineral density (BMD) in elderly Italian subjects. In 866 women (age 64.2 ± 6.5 yr) and 168 men (age 65.1 ± 6.1 yr), we measured BMD at lumbar spine, at femur, at the total body, and at the right hand. In all subjects, we also measured sex hormones, 25-hydroxyvitamin D, bone markers, and calcium intake. In both men and women, all body composition parameters had significant positive correlations with BMD at all sites after adjusting for age only; after adjusting also for body weight only lean mass (LM) remained positively associated with BMD at all sites except BMD at lumbar spine. In males, LM was associated with BMD at all sites, whereas android fat was associated with BMD at lumbar spine, at femur, and at whole body. In females, fat mass (FM) was positively and age inversely associated with BMD at all sites, whereas gynoid fat and alkaline phosphatase were inversely associated with BMD at lumbar spine and at femur. In conclusion, the role of LM seems more important in males, whereas in women the role of FM prevails with negative associations between gynoid fat and BMD.     

Association Between Lean Mass and Handgrip Strength With Bone Mineral Density in Physically Active Postmenopausal Women

The present study evaluated 117 physically active postmenopausal women (67.8 ± 7.0 yr) who performed neuromotor physical tests (strength, balance, and mobility). Body composition (lean mass [g], fat mass [g], and % fat) and bone mineral density (BMD) of lumbar spine (L1–L4), femoral neck, and total body were measured by dual-energy X-ray absorptiometry. Following the World Health Organization criteria, osteoporosis was found in at least 1 analyzed site in 33 volunteers (28.2%): 30 (25.6%) in lumbar spine and 9 (7.7%) in femoral neck. Body weight was strongly and positively related to BMD in all sites, but the most important component of body composition was lean mass, also significantly related to all BMD sites, whereas fat mass was weakly related to the femoral neck BMD. Percent fat did not correlate with any BMD site. Of all the physical tests, the handgrip strength was most importantly related to lumbar spine, femoral neck, and total body (r = 0.49, p < 0.001; r = 0.56, p < 0.001; and r = 0.52, p < 0.001, respectively). The static body balance presented a weak but significant positive correlation only with lumbar spine. Our results suggest that strategies aiming to improve muscle strength and lean mass must contribute to the bone health of physically active postmenopausal women.     

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.     

High serum total homocysteine levels accelerate hip bone loss in healthy premenopausal women and men

IntroductionDespite extensive evidence demonstrating the direct, detrimental role of homocysteine on bone metabolism, the effects of serum total homocysteine (tHcy) on bone loss are still equivocal. In the present study, we performed a longitudinal study on healthy participants of various ages of both sexes in order to investigate the association between serum tHcy concentrations and annualized changes in bone mineral density (BMD).MethodsA total of 460 Koreans ≥ 30 years of age received comprehensive, routine health examinations for an average period of 3 years. The BMD at proximal femur sites was measured with dual-energy X-ray absorptiometry using the same equipment at baseline and follow-up.ResultsAfter adjusting for potential confounders, the rates of bone loss at the proximal femur sites were significantly accelerated in a dose–response fashion across increasing tHcy concentrations in premenopausal women and men, but not in postmenopausal women. Consistently, compared with subjects in the lowest tHcy quartile, premenopausal women in the third and/or highest tHcy quartile and men in the highest tHcy quartile showed significantly higher rates of bone loss at all proximal femur sites (p = 0.015–0.048) and at the total femur and femur neck (p = 0.008–0.013), respectively. In contrast, there were no differences in terms of bone loss among the tHcy quartiles for postmenopausal women.ConclusionThese data provide the first clinical evidence that increased tHcy levels could be an independent risk factor for the future deterioration of bone mass in premenopausal women and men.     

Statut osseux au cours de l'hyperparathyroïdie primitive mesurée par densité minérale osseuse régionale par densitométrie corps entier et ultrasonographie quantitative au calcanéum

To assess the bone mineral density status in primary hyperparathyroidism (PHPT), we studied 64 females with PHPT and 17 healthy women. Regional BMD (arms, trunk, legs) from the whole body scan and conventional sites (lumbar spine, femur, radius) were assessed by DXA. Quantitative ultrasound (QUS) imaging measurements were performed at calcaneus. Sixteen women had history of renal lithiasis, 11 had low impact fracture and 37 women had neither renal lithiasis nor fracture. In the entire group, the mean Z-scores were significantly decreased at all sites (lumbar spine, femur, radius). In all clinical subgroups, the mean Z-scores were significantly decreased at radius. The mean Z-scores in premenopausal women were significantly decreased comparatively to postmenopausal women at lumbar spine and femur. In a group of PHPT females matched to controls for age and BMI, only BMD values at radius were lower in PHPT patients than in control (P <0.03). However, from the whole body scan data, all sites but no trunk were significantly involved in PHPT patients (P <0.04). Using QUS measurements at calcaneus, the BUA but not SOS in PHPT females was significantly lower (P =0.03) than in controls. Our results suggest that low BMD at lumbar spine and femur is encountered preferentially in premenopausal women. The BMD decrease predominates at limbs in PHPT with presumably a gradient from proximal to distal part of the limbs. Indeed, the distal part of the limbs are the most affected areas in PHPT whatever the amount of cortical or trabecular bone.     

Serum uric acid plays a protective role for bone loss in peri- and postmenopausal women: A longitudinal study

ObjectiveOxidative stress has been linked to osteoporosis. Serum uric acid (UA), a strong endogenous antioxidant, has been associated with higher bone mineral density (BMD), lower bone turnover and lower prevalence of fractures in a large cross-sectional study of men. Whether this relationship is present in women and how UA relates to changes in BMD longitudinally has not been examined.MethodsA sample of 356 peri- and postmenopausal women, mean age 60.5 years was studied. Each individual had baseline BMD and body composition measurements by dual energy x-ray absorptiometry (DXA) and at least one repeat measure, on average 9.7 years later. Annual rate of change in BMD (A%ΔBMD) was calculated. UA was measured at each DXA visit. Calciotropic hormones and bone turnover markers were measured at the final visit only.ResultsCross-sectional data analyses revealed that women with higher UA levels had significantly higher absolute BMD measures at all skeletal sites. These women also had higher measures of body weight and its components such as lean mass (LM) and fat mass (FM). Results of multiple regression analyses showed a positive association between UA and BMD that remained significant even after accounting for possible confounders including LM and FM. Regression analyses of the longitudinal BMD data demonstrated significant associations between serum UA levels and annual rates of change in BMD at all skeletal sites. After adjustment associations remained significant for lumbar spine, forearm and whole body BMD but not for hip BMD.ConclusionHigher serum UA levels appear to be protective for bone loss in peri- and postmenopausal women and this relationship is not affected by changes in body composition measures.     

Denosumab Significantly Increases DXA BMD at Both Trabecular and Cortical Sites: Results From the FREEDOM Study

Denosumab is an approved therapy for postmenopausal women with osteoporosis at high or increased risk for fracture. In the FREEDOM study, denosumab reduced fracture risk and increased bone mineral density (BMD). We report the spine and hip dual-energy X-ray absorptiometry (DXA) BMD responses from the overall study of 7808 women and from a substudy of 441 participants in which more extensive spine and hip assessments as well as additional skeletal sites were evaluated. Significant BMD improvements were observed as early as 1 mo at the lumbar spine, total hip, and trochanter (all p < 0.005 vs placebo and baseline). BMD increased progressively at the lumbar spine, total hip, femoral neck, trochanter, 1/3 radius, and total body from baseline to months 12, 24, and 36 (all p < 0.005 vs placebo and baseline). BMD gains above the least significant change of more than 3% at 36 months were observed in 90% of denosumab-treated subjects at the lumbar spine and 74% at the total hip, and gains more than 6% occurred in 77% and 38%, respectively. In conclusion, denosumab treatment resulted in significant, early, and continued BMD increases at both trabecular and cortical sites throughout the skeleton over 36 mo with important gains observed in most subjects.     

Associations between body mass index,lean and fat body mass and bone mineral density in middle-aged Australians: The Busselton Healthy Ageing Study

Low BMI is a risk factor for osteoporosis, but it is not clear if relationships between BMI, lean mass (LM), fat mass (FM) and BMD are consistent across different levels of BMI. We studied 1929 Caucasian participants (1014 females) aged 45–66 years in the Busselton Healthy Ageing Study in Western Australia. Body composition and BMD of total body, lumbar spine, total hip and femoral neck were measured using DXA. From generalized additive models, the positive relationships between BMI and BMD were weaker at high BMI, particularly at the spine and in males. In the entire cohort, adjusting for relevant covariates, LM and FM were significant predictors of all BMD measures in both genders. In men, analysis by tertiles of BMI showed that LM and FM (in kg) were positively associated with BMD (in mg/cm²) in tertile 1 except for LM and spine BMD (LM β: 5.18–6.80, FM β: 3.38–9.24, all P < 0.05), but not in the middle or upper tertiles (LM β: − 3.12–3.07, FM β: − 4.75–1.82, P > 0.05). In women, LM was positively associated with BMD in each tertile of BMI, except for spine BMD in the upper tertile, with regression coefficients lower in the upper tertile (β: 5.16–9.95, 5.76–9.56 and 2.80–5.78, respectively, all P < 0.05). FM was positively associated with total body, spine and total hip BMD in women in BMI tertile 1 (β: 2.86–6.68, P < 0.05); these associations were weaker or absent in the middle and upper tertiles. In conclusion, in middle-aged adults the positive relationships between lean or fat mass with BMD among those with higher BMI are absent in males and weaker in females.     

In vivo Precision of the GE Lunar iDXA Densitometer for the Measurement of Total-Body, Lumbar Spine, and Femoral Bone Mineral Density in Adults

Knowledge of precision is integral to the monitoring of bone mineral density (BMD) changes using dual-energy X-ray absorptiometry (DXA). We evaluated the precision for bone measurements acquired using a GE Lunar iDXA (GE Healthcare, Waukesha, WI) in self-selected men and women, with mean age of 34.8 yr (standard deviation [SD]: 8.4; range: 20.1–50.5), heterogeneous in terms of body mass index (mean: 25.8 kg/m²; SD: 5.1; range: 16.7–42.7 kg/m²). Two consecutive iDXA scans (with repositioning) of the total body, lumbar spine, and femur were conducted within 1 h, for each subject. The coefficient of variation (CV), the root-mean-square (RMS) averages of SDs of repeated measurements, and the corresponding 95% least significant change were calculated. Linear regression analyses were also undertaken. We found a high level of precision for BMD measurements, particularly for scans of the total body, lumbar spine, and total hip (RMS: 0.007, 0.004, and 0.007 g/cm²; CV: 0.63%, 0.41%, and 0.53%, respectively). Precision error for the femoral neck was higher but still represented good reproducibility (RMS: 0.014 g/cm²; CV: 1.36%). There were associations between body size and total-body BMD and total-hip BMD SD precisions (r = 0.534–0.806, p < 0.05) in male subjects. Regression parameters showed good association between consecutive measurements for all body sites (r² = 0.98–0.99). The Lunar iDXA provided excellent precision for BMD measurements of the total body, lumbar spine, femoral neck, and total hip.     

Marrow fat composition in anorexia nervosa

PurposeWomen with anorexia nervosa (AN) have increased marrow fat despite severe depletion of body fat. Recent studies have suggested that marrow fat composition may serve as a biomarker for bone quality. The purpose of our study was to investigate marrow fat composition of the femur using proton MR spectroscopy (¹H MRS), and the relationship between measures of marrow fat composition and BMD and body composition in women with AN and normal-weight controls.Materials and methods14 women with AN (29.5 ± 1.9 years) and 12 age-matched normal-weight controls underwent ¹H MRS to determine total marrow fat content and marrow fat composition of the femoral diaphysis and soleus intramyocellular lipids und unsaturated muscle lipids. MRI was performed to quantify abdominal fat, thigh fat and muscle areas. Lumbar spine BMD, fat and lean mass were assessed by DXA.ResultsSubjects with AN had higher marrow fat content (p < 0.05), but similar marrow fat composition (p > 0.05) compared to normal-weight controls. There was an inverse association between marrow methylene protons, an estimate of fatty acid (FA) saturated bonds, and lumbar spine BMD (r = − 0.52, p = 0.008) independent of %ideal body weight (%IBW). Olefinic protons at 5.3 ppm, an estimate of FA unsaturated bonds, were inversely associated with body fat depots, independent of %IBW, and positively associated with soleus unsaturation (p ≤ 0.05).ConclusionWomen with AN have higher total femoral marrow fat but similar composition compared to normal-weight controls. The degree of marrow FA saturation correlates inversely with BMD, suggesting that saturated lipids may have negative effects on BMD. The degree of marrow FA unsaturation correlates positively with soleus unsaturation, suggesting that marrow fat composition may be influenced by the same factors as ectopic lipid composition in muscle.     

Contribution of Android and Gynoid Adiposity to Bone Mineral Density in Healthy Postmenopausal Thai Women

Dual-energy X-ray absorptiometry (DXA) is one of the major tools for assessing the whole body and regional body composition and body adiposity. Various body composition parameters including android fat mass (AFM), gynoid fat mass (GFM), and android-to-gynoid fat ratio (AG fat ratio) obtained from whole body DXA can be used as a reliable surrogate marker for regional body composition analysis. This study aimed to explore the contribution of android and gynoid adiposity to bone mineral density (BMD) in healthy postmenopausal Thai women. This cross-sectional study enrolled 1448 healthy Thai women, ages 40–90 without medication history or known disease affecting the BMD. Lumbar spine (LS), total femur, and femoral neck BMDs, AFM, GFM, and AG fat ratio were measured by DXA. To evaluate the contribution of android and gynoid adiposity with various measures of BMDs, univariable and multivariable linear regression analyses were used to estimate the regression coefficients. AFM, GFM, and AG fat ratio had a significant positive association with BMD of all measured sites (p < 0.001) in the univariate analysis. The strongest association was found between AG fat ratio and LS BMD (β = 0.156, p ≤ 0.001). In multivariate linear regression analysis, the results continued to show a positive association between AFM and GFM at all skeletal sites after adjusting for age, height, and total body lean mass. Relationship between AG fat ratio and BMD was found only in LS region. GFM had a strongest positive effect with BMD at the LS, total femur, and femoral neck regions. Higher android and gynoid adiposity was associated with higher BMD. GFM rather than AFM shows the strongest positive association with BMDs in postmenopausal Thai women.     

Contribution of Serum Inflammatory Markers to Changes in Bone Mineral Content and Density in Postmenopausal Women: A 1-Year Investigation

Bone formation and resorption are influenced by inflammatory processes. We examined the relationships among inflammatory markers and bone mineral content (BMC) and density (BMD) and determined the contribution of inflammatory markers to 1-yr changes in BMC and BMD in healthy postmenopausal women. This analysis included 242 women at baseline from our parent Soy Isoflavones for Reducing Bone Loss project who were randomly assigned to 1 of 3 treatment groups: placebo, 80 mg/d soy isoflavones, or 120 mg/d soy isoflavones. BMD and BMC from the lumbar spine (LS), total proximal femur (hip), and whole body were measured by dual energy X-ray absorptiometry and the 4% distal tibia by peripheral quantitative computed tomography. Serum inflammatory markers (C-reactive protein, interleukin [IL]-1β, IL-6, tumor necrosis factor-alpha [TNF-α], and white blood cell count [WBC]) were measured at baseline, 6, and 12 mo. Because of attrition or missing values, data analysis at 12 mo includes only 235 women. Significant associations among IL-6, TNF-α, and WBC were observed with percent change in LS, hip, and whole body BMC and BMD. Multiple regression analysis indicated that in combination inflammatory markers accounted for 1.1–6.1% of the variance to the observed 12-mo changes in BMC and BMD. Our results suggest that modifying inflammatory markers, even in healthy postmenopausal women, may possibly reduce bone loss.     

Effects of combined whole-body vibration and resistance training on muscular strength and bone metabolism in postmenopausal women

Whole-body vibration (WBV) has been shown to be osteogenic in animal models; however, its application in humans is not clear. The purpose of this study was to examine the effects of an 8-month program involving WBV plus resistance training on bone mineral density (BMD) and bone metabolism in older postmenopausal women. Fifty-five estrogen-deficient postmenopausal women were assigned to a resistance training group (R, n = 22), a WBV plus resistance training group (WBVR, n = 21), or a control group (CON, n = 12). R and WBVR performed upper and lower body resistance exercises 3 days/week at 80% 1 Repetition Maximum (1RM). WBVR received vibration (30–40 Hz, 2–2.8g) in three different positions preceding the resistance exercises. Daily calcium intake, bone markers (Bone alkaline phosphatase (Bone ALP); C-terminal telopeptide of Type I collagen (CTX), and BMD of the spine, dual femur, forearm, and total body (DXA) were measured at baseline and after the intervention. At baseline, there were no significant group differences in strength, BMD, or bone marker variables. After 8 months of R or WBVR, there were no significant group or time effects in Bone ALP, CTX, or total body, spine, left hip or right trochanter BMD. However, right total hip and right femoral neck BMD significantly (p < 0.05) decreased in all groups. A group × time interaction (p < 0.05) was detected at radius 33% BMD site, with CON slightly increasing, and WBVR slightly decreasing. R and WBVR significantly (p < 0.05) increased 1RM strength for all exercises, while CON generally maintained strength. WBVR had significantly (p < 0.05) greater percent increases in muscular strength than R at 4 months for lat pull down, seated row, hip abduction and hip adduction and at 8 months for lat pull down, hip abduction and hip adduction. Bone metabolism in postmenopausal women was not affected by resistance training either with or without WBV. In contrast, the addition of WBV augmented the positive effects of resistance training on muscular strength in these older women.     

Effect of resistance exercise on bone mineral density in premenopausal women

ObjectiveTo assess the effect of 9 months of strength training on total body and regional bone mineral density (BMD, g/cm²) in 58 premenopausal women aged 30–50 years.MethodsParticipants were randomized to either twice weekly supervised strength training for 15 weeks followed by 24 weeks of unsupervised training (treatment group) or control group. Height, weight, maximal muscular strength, nutrient intake and physical activity were assessed. Total body dual energy X-ray absorptiometry (DXA, Lunar Prodigy) scans were taken and analyzed for body composition (lean and fat mass), and BMD for total body and its sub-regions (spine, hip, arms and legs). All measurements were performed at baseline, 15 and 39 weeks. Analysis of covariance was used to assess group differences in BMD change adjusted for baseline BMD, weight, energy and calcium intake.ResultsAt baseline, the two groups had similar BMD and body size characteristics ( P < 0.05 for all), except that the treatment group had lower body weight (?7.1 kg), and higher energy (+259 kJ/d) and calcium (+232 mg/d) intake at baseline. Adjusted % change in BMD over 15 weeks (0.5% vs. 0.4%) or 39 weeks (0.9% vs. 1.2%) did not differ significantly between the exercise and control groups, respectively. The exercise group increased BMD at the spine and legs (1–2.2%), while there was no change in the controls, but differences between groups were not significant.ConclusionStrength training over 9 months did not lead to significantly greater change in total body or regional BMD in premenopausal women.     

Treinamento de força versus hidroginástica: uma análise transversal comparativa da densidade mineral óssea em mulheres na pós-menopausa

IntroductionMany studies have shown that resistance training has a positive effect on bone mineral density (BMD). However, few studies have compared the BMD of individuals undergoing resistance training and those training aquatic weight-bearing exercises.ObjectiveTo compare, in a cross-sectional study, the BMD of postmenopausal women undergoing resistance training and postmenopausal women training aquatic weight-bearing exercises.MethodsThe sample comprised 63 women divided into the following three groups: resistance training (STRENGTH: n = 15; 51.4 ± 2.7 years); aquatic weight-bearing exercises (WATER: n = 22; 54.5 ± 3.3 years); and non-trained controls (CONTROL: n = 26; 52.0 ± 3.3 years). All volunteers were on hormone replacement therapy for at least one year. The STRENGTH and WATER groups were training for at least one year prior to study beginning (mean years of training – STRENGTH: 4.5 ± 2.0; WATER: 4.2 ± 2.2).ResultsThe STRENGTH group had higher BMD of total body, femoral neck, lumbar spine L2-L4 as compared with the CONTROL group (all P < 0.05). The WATER group had higher BMD of total body, total hip, lumbar spine L2-L4 as compared with the CONTROL group (all P < 0.05). However, no difference was observed between the STRENGTH and WATER groups regarding the sites assessed.ConclusionsThose findings suggest that not only the resistance training, but also aquatic weight-bearing exercises might be a non-pharmacological strategy to prevent BMD loss in postmenopausal women.     

Reduced physical activity corresponds with greater bone loss at the trabecular than the cortical bone sites in men

Previous research has been inconclusive as to whether high peak bone mineral density (BMD, g/cm²) resulting from previous physical activity is retained with reduced activity later in life. The aim of this 12-year longitudinal study was to investigate the association between BMD loss and reduced physical activity (h/wk) at trabecular and cortical bone sites in men. Three groups with a mean age of 17 years at baseline were investigated: i) 51 athletes who discontinued their active careers during the follow-up period (former athletes), ii) 16 athletes who were active throughout the follow-up period (active athletes), and iii) 25 controls. BMD loss at the hip, spine, and pelvis (mainly trabecular bone) was compared to BMD loss at femur, humerus, and legs (mainly cortical bone) during a 12-year follow-up period. Across the total follow-up period in the total cohort, reduced physical activity was more strongly associated with changes at trabecular BMD sites, i.e. hip, spine, and pelvis (B = 0.008–0.005 g/cm² per weekly hour physical activity (h), p < 0.001), than at cortical bone sites, i.e. humerus, legs (B = 0.002–0.003 g/cm²/h, p < 0.05), and femur (p > 0.05). At the final follow-up, former athletes showed higher BMD than controls only at the cortical bone sites of the humerus, legs, and femur (difference 0.05–0.10 g/cm², p < 0.05). In conclusion, this study indicates that predominantly trabecular bone is lost with reduced physical activity levels in young men. Benefits were still evident at the more cortical sites eight years after the discontinuation of an active sports career.     

Areal bone mineral density in children and adolescents with Marfan syndrome: Evidence of an evolving problem

Marfan syndrome (MFS), an autosomal dominant disorder of connective tissue, is due to defective fibrillin-1. Defects involve the cardiovascular system, the eye, the lungs, and the skeleton. The aim of the current study was to characterize the bone mineral status in children and adolescents with MFS. We performed an observational cross-sectional study and a longitudinal follow-up of two years.We enrolled 73 young patients with MFS (3–17 years). A subset of 44 patients participated in the longitudinal study. Healthy children were studied as controls for biochemical analyses. Bone mineral density (BMD) was measured at lumbar spine, femoral neck and total femur by dual-energy X-ray absorptiometry. BMD values were expressed as Z-scores adjusted for height using height-for-age Z-scores. BMD measurements corrected for height were significantly lower than reference at all skeletal sites (P < 0.0001). Patient on cardiac treatment with losartan had lower BMD measurements corrected for height compared to non-treated patients. Total femur BMD decreased significantly over time (P = 0.027). BMD at the other two skeletal sites did not change significantly during follow-up, but remained significantly low compared to reference (P < 0.0001). In conclusion, young patients with MFS have markedly low BMD at the lumbar spine and femur, and values show a tendency to decrease over time in the peripheral skeleton. Because increased life expectancy of MFS patients, the reduced BMD during childhood may lead to a low peak bone mass, increasing the fracture risk during adult life.     

Meta-analysis of walking for preservation of bone mineral density in postmenopausal women

Whilst exercise is recommended for optimum bone health in adult women, there are few systematic reviews of the efficacy of walking as singular exercise therapy for postmenopausal bone loss. The aim of this study was to assess the effects of prescribed walking programmes on bone mineral density (BMD) at the hip and spine in postmenopausal women and to determine if effects are modified by variations in protocol design. We undertook a systematic review and meta-analysis of randomised (RCTs) and non-randomised controlled trials. Electronic bibliographic databases, key journals and reference lists of reviews and articles were searched to identify studies for inclusion. Randomised and non-randomised controlled trials assessing the effects of walking on lumbar spine, femoral neck and total hip BMD, measured by radiographic techniques, among sedentary postmenopausal women were eligible for inclusion. Two independent reviewers assessed studies for eligibility. Reported absolute BMD outcomes were combined in the analysis. Weighted mean differences (WMD) were calculated using a fixed and random-effects models. Heterogeneity among trials was examined using the Q statistic and I² methods. Potential publication bias was assessed through funnel plot inspection. Assessment of trial quality was also performed using the widely used instrument devised by Jadad et al. [Jadad AR, Moore RA, Carroll D, Jenkinson C, Reynolds DJM, Gavaghan DJ, et al. Assessing the quality of reports of randomized clinical trials: Is blinding necessary? Cont Clin Trials 1996; 17:1–12].Eight trials were eligible for inclusion. Treatment duration ranged from 6 to 24 months. All eight trials reported BMD data at the lumbar spine following walking interventions among postmenopausal women. Meta-analysis showed no significant change in BMD at this site [WMD (fixed-effect) 0.007 g/cm² 95% CI (− 0.001 to 0.016); P = 0.09)]. BMD data at the femoral neck were available from five trials among postmenopausal women. Results were inconsistent (I² = 51.4%) in showing a positive effect of walking on BMD at this site [WMD (random-effects) 0.014 g/cm² 95% CI (0.000 to 0.028); P = 0.05). Insufficient data were available for meta-analysis of the total hip site. Funnel plots showed some asymmetry for negative lumbar spine BMD outcomes. Trial quality scores ranged from 0 to 3 from the Jadad scale of 0 to 5.We conclude that regular walking has no significant effect on preservation of BMD at the spine in postmenopausal women, whilst significant positive effects at femoral neck are evident. However, diverse methodological and reporting discrepancies are apparent in the published trials on which these conclusions are based. Other forms of exercise that provide greater targeted skeletal loading may be required to preserve bone mineral density in this population.     

Association of dietary consumption and serum levels of vitamin A and β-carotene with bone mineral density in Chinese adults

BackgroundFormer studies suggested an adverse effect of hypervitaminosis A on bone health, while the effects of retinol and its precursor (β-carotene) remain uncertain in populations consuming vitamin A (VA) mainly from plant sources.ObjectiveWe investigated the association of serum, dietary retinol, and β-carotene with bone mineral density (BMD) in Chinese adults.MethodsWe recruited 2101 women and 1053 men (aged 40–75 years) in Guangzhou, China. Dietary intake was assessed through face-to-face interviews with food-frequency questionnaires at baseline and 3 years later. Serum levels of retinol and β-carotene were determined by HPLC using a baseline specimen, and the BMD for the whole body (WB), lumbar spine (LS), total hip (TH), and femur neck (FN) were measured using dual energy X-ray absorptiometry at follow-up.ResultsIn general, greater levels of serum retinol, β-carotene, and the β-carotene-to-retinol ratio were associated with a higher BMD after adjustment for potential covariates in the total sample. BMD values in the top (vs. bottom) quartile were increased by 2.06% (TH) for retinol; 2.87% (WB), 2.51% (LS), 3.10% (FN) for β-carotene; 2.21% (WB) and 2.05% (FN) for the β-carotene-to-retinol ratio in the total sample (all p < 0.05). A significant positive association with BMD was observed for dietary intake of β-carotene and total VA in retinol equivalents at the hip sites in the total sample.ConclusionHigher circulating and dietary levels of VA and β-carotene and higher serum β-carotene-to-retinol ratios were positively associated with BMD in Chinese adults consuming relatively low levels of VA, mainly from plant foods.