Changes in Bone Mineral Density, Body Composition and Adiponectin Levels in Morbidly Obese Patients after Bariatric Surgery

Background  Gastric bypass surgery (GBP) is increasingly used as a treatment option in morbid obesity. Little is known about the effects of this surgery on bone mineral density (BMD) and the underlying mechanisms. To evaluate changes on BMD after GBP and its relation with changes in body composition and serum adiponectin, a longitudinal study in morbid obese subjects was conducted. Methods  Forty-two women (BMI 45.0 ± 4.3 kg/m²; 37.7 ± 9.6 years) were studied before surgery and 6 and 12 months after GBP. Percentage of body fat (%BF), fat-free mass (FFM), and BMD were measured by dual-energy X-ray absorptiometry and serum adiponectin levels by RIA. Results  Twelve months after, GBP weight was decreased by 34.4 ± 6.5% and excess weight loss was 68.2 ± 12.8%. Significant reduction (p < 0.001) in total BMD (−3.0 ± 2.1%), spine BMD (−7.4 ± 6.8%) and hip BMD (−10.5 ± 5.6%) were observed. Adiponectin concentration increased from 11.4 ± 0.7 mg/L before surgery to 15.7 ± 0.7 and 19.8 ± 1.0 at the sixth and twelfth month after GBP, respectively (p < 0.001). Thirty-seven percent of the variation in total BMD could be explained by baseline weight, initial BMD, BF reduction, and adiponectin at the twelfth month (r ² = 0.373; p < 0.001). Adiponectin at the twelfth month had a significant and positive correlation with the reduction of BMD, unrelated to baseline and variation in body composition parameters (adjusted correlation coefficient: r = 0.36). Conclusion  GBP induces a significant BMD loss related with changes in body composition, although some metabolic mediators, such as adiponectin increase, may have an independent action on BMD which deserves further study.     

Genetic influences on bone loss in the San Antonio Family Osteoporosis study

Summary  The genetic contribution to age-related bone loss is not well understood. We estimated that genes accounted for 25–45% of variation in 5-year change in bone mineral density in men and women. An autosome-wide linkage scan yielded no significant evidence for chromosomal regions implicated in bone loss. Introduction  The contribution of genetics to acquisition of peak bone mass is well documented, but little is known about the influence of genes on subsequent bone loss with age. We therefore measured 5-year change in bone mineral density (BMD) in 300 Mexican Americans (>45 years of age) from the San Antonio Family Osteoporosis Study to identify genetic factors influencing bone loss. Methods  Annualized change in BMD was calculated from measurements taken 5.5 years apart. Heritability (h²) of BMD change was estimated using variance components methods and autosome-wide linkage analysis was carried out using 460 microsatellite markers at a mean 7.6 cM interval density. Results  Rate of BMD change was heritable at the forearm (h² = 0.31, p = 0.021), hip (h² = 0.44, p = 0.017), spine (h² = 0.42, p = 0.005), but not whole body (h² = 0.18, p = 0.123). Covariates associated with rapid bone loss (advanced age, baseline BMD, female sex, low baseline weight, postmenopausal status, and interim weight loss) accounted for 10% to 28% of trait variation. No significant evidence of linkage was observed at any skeletal site. Conclusions  This is one of the first studies to report significant heritability of BMD change for weight-bearing and non-weight-bearing bones in an unselected population and the first linkage scan for change in BMD.     

Habitual and Low-Impact Activities are Associated with Better Bone Outcomes and Lower Body Fat in Older Women

The influence of habitual and low-impact physical activity (PA) on bone health and soft tissue including bone-free lean (BFL) and fat mass is less elucidated than the influence of high-impact activities. This study examines the interactive effects of PA and soft tissue on bone mineral density (BMD) and content (BMC) in healthy Caucasian women, aged 68.6 ± 7.1 years, with body mass index (BMI) of 26.0 ± 3.8 kg/m² evaluated at baseline and every 6 months for 3 years. Measurements/assessments included BMD/BMC and soft tissue (by dual-energy X-ray absorptiometry), anthropometrics, dietary intake, and PA. Activities assessed were past activity, present heavy housework, gardening, do-it-yourself activities, stair-climbing, walking, walking pace, sports/recreation, and total activity. Baseline analyses revealed significant positive associations between past activity, heavy housework, faster-paced walking, BFL, and BMD/BMC of various skeletal sites. Prospective analyses showed subjects with more walking hours/week had significantly higher BMD/BMC of several skeletal sites (P < 0.05). Stratification by cumulative (over 3 years) median for heavy housework, walking, sports/recreational, and total activities revealed higher BMD and BMC in the femur and spine (P = 0.01) in subjects with those activities above median. Multivariate analysis of covariance results revealed that weight had the strongest influence on BMD and BMC, followed by BFL. Various modes of PA were negatively associated with BMI and fat but not with BFL. In conclusion, heavy housework, walking (faster pace), sports/recreational activities, and overall total participation in low-impact PA were beneficial for bone and for achieving more favorable body weight and fat but were not associated with BFL. The results indicate that even habitual activities engaged in by older women could benefit their bone and diminish body fat.     

Total body,lumbar spine and hip bone mineral density in overweight adolescent girls: decreased or increased?

Despite the epidemic of overweight adolescents, the effect of being overweight on bone mineral density (BMD) during this period is poorly understood. However, recent studies have suggested that overweight adolescents have lower BMD compared to normal-weighted adolescents after adjusting for body weight. The aim of this study was to determine the influence of being overweight on bone status in a group of adolescent girls. This study included 22 overweight (BMI >25 kg/m2) adolescent girls (15.4 ± 2.4 years old) and 20 maturation-matched (15.2 ± 1.9 years old) controls (BMI <25 kg/m2). Bone mineral area, bone mineral content, BMD at the whole body (WB), lumbar spine (L2–L4), femoral neck (FN), total hip (TH) and body composition (lean mass and fat mass) were assessed by dual-energy X-ray absorptiometry (DXA). Calculation of the bone mineral apparent density (BMAD) was completed for the WB and for L2–L4. Expressed as crude values, DXA measurements of BMD at all bone sites (TB, L2–L4, TH and FN) were higher in overweight adolescent girls compared to controls. After adjusting for either body weight, lean mass or fat mass, these differences disappeared. Finally, BMAD of the L2–L4 remained higher in overweight girls compared to controls after adjusting for lean mass. We conclude that overweight adolescent girls do not have lower BMD when compared with controls, even when BMD values are adjusted for weight, lean mass or fat mass.     

Weight and body mass index predict bone mineral density and fractures in women aged 40 to 59 years

Summary  Weight and body mass index are associated with low bone mineral density and fractures in older women. This retrospective cohort study confirms a similar relationship in women aged 40 to 59 years. Introduction  Risk factors for the prediction of osteoporosis and fractures have been less thoroughly studied in younger women. We evaluated the associations between weight, body mass index (BMI), the Osteoporosis Self-Assessment Tool (OST), bone mineral density (BMD) and fracture risk in women aged 40 to 59 years. Methods  Using administrative health management databases, we conducted a retrospective cohort study in 8,254 women aged 40–59 years who had baseline BMD testing. Linear regression and Cox proportional multivariate models were created to examine the associations with weight, BMI, OST, BMD, and subsequent fractures throughout a 3.3-year follow-up. Results  Body weight, BMI, and OST had a similar overall performance in their ability to classify women with femoral neck T-score ≤ −2.5. Throughout 27,256 person years of observation, 225 women experienced one or more fractures. After adjustment for age, prevalent fractures, and use of corticosteroids, each standard deviation decrease in weight was associated with a 19% increase in the risk of incident fracture (95% CI: 1.01–1.35). Femoral neck BMD and the presence of prevalent fractures were also associated with the risk of incident fractures. Conclusions  Low weight and BMI predict osteoporosis and are associated with increased fracture risk in younger women. The negative impact of low body weight on bone health should be more widely recognized. On behalf of the Manitoba Bone Density Program.     

Evaluation of Bone Disease in Morbidly Obese Women After Gastric Bypass and Risk Factors Implicated in Bone Loss

Background  In patients undergoing gastric bypass, massive weight loss and impairment of calcium intake and absorption in the duodenum and proximal jejunum may increase the risk of bone mass loss and fractures. However, few data are available regarding the impact of this surgery on the skeleton. The aim of our study was to examine the skeletal changes in a cohort of morbidly obese Caucasian women during the first year after gastric bypass and to analyse the factors implicated in the development of bone loss. Methods  Sixty-two morbidly obese white women aged 45.3 ± 8.9 years were studied. Anthropometric measurements, bone mineral density (BMD) screening using dual-energy X- ray absorptiometry and plasma determinations of calcium, phosphorus, parathyroid hormone (PTH), 25-hydroxyvitamin D [25(OH) D₃] and insulin-like growth factor-I (IGF-I) were made prior to and 12 months after surgery. Results  A year after surgery, BMD significantly decreased at the femoral neck (10.2 ± 5.7%) and at the lumbar spine (3.2 ± 4.4%). In the follow-up, 16.1% of women had osteopenia at the femoral neck and 19.3% at the lumbar spine, and 1.6% developed osteoporosis at the lumbar spine. Patients with bone disease were significantly older; the percentage of women with menopause was greater in this group and had lower initial and final values of lean mass. However, no differences in body mass index, weight loss, fat mass, calcium, PTH, 25(OH) D₃ or IGF-I values were found between groups. In the logistic regression analysis, lean mass 12 months after surgery and menopause were found to be the main determinants of osteopenia after adjusting for age with odds ratios of 0.82 and 9.13, respectively. Conclusions  There is a significant BMD loss at the femoral neck and lumbar spine a year after gastric bypass. Menopausal patients and those with greater lean mass loss are at greater risk and, consequently, should be closely followed up with periodic densitometries.     

Effect of dehydroepiandrosterone supplementation on bone mineral density,bone markers,and body composition in older adults: the DAWN trial

Summary We present results of a randomized, placebo-controlled trial to examine the effect of 50 mg daily oral DHEA supplementation for one year on bone mineral density (BMD), bone metabolism and body composition in 225 healthy adults aged 55 to 85 years. Introduction Dehydroepiandrosterone (DHEA) levels decline dramatically with age, concurrent with the onset of osteoporosis, suggesting a role for DHEA supplementation in preventing age-related bone loss. Methods We conducted a randomized, placebo-controlled trial to examine the effect of 50 mg daily oral DHEA supplementation for one year on bone mineral density (BMD), bone metabolism and body composition in 225 healthy adults aged 55 to 85 years. Results DHEA treatment increased serum DHEA and DHEA sulfate levels to concentrations seen in young adults. Testosterone, estradiol and insulin-like growth factor (IGF-1) levels increased in women (all p < 0.001), but not men, receiving DHEA. Serum C-terminal telopeptide of type-1 collagen levels decreased in women (p = 0.03), but not men, whereas bone-specific alkaline phosphatase levels were not significantly altered in either sex. After 12 months, there was a positive effect of DHEA on lumbar spine BMD in women (p = 0.03), but no effect was observed for hip, femoral neck or total body BMD, and no significant changes were observed at any site among men. Body composition was not affected by DHEA treatment in either sex. Conclusion Among older healthy adults, daily administration of 50 mg of DHEA has a modest and selective beneficial effect on BMD and bone resorption in women, but provides no bone benefit for men.     

Regulation of Bone Mineral Density in Morbidly Obese Women: A Cross-sectional Study in Two Cohorts Before and After Bypass Surgery

Background  The mechanisms by which increased body weight influence bone mass density (BMD) are still unknown. The aim of our study was to analyze the relationship between anthropometric and body composition variables, insulin growth factor-I (IGF-I), adiponectin and soluble tumor necrosis factor-α receptors (sTNFR) 1 and 2 with BMD in two cohorts of morbid obese patients, before and after bypass surgery. Methods  The first cohort included 25 women aged 48 ± 7.6 years studied before bypass surgery. The second included 41 women aged 46 ± 9.2 years, 12 months after surgery. We studied anthropometric variables obtained from whole body DEXA composition analysis. Serum IGF-I, intact serum parathyroid hormone, 25-hydroxivitamin D₃, plasma adiponectin concentrations, sTNFR1, sTNFR2 concentrations were measured. Results  In the first cohort, the BMI was 44.5 ± 3.6 kg/m², parathyroid hormone, IGF-I, and adiponectin concentrations were lower, and sTNFR1 concentrations were higher than in the second cohort. In the multiple regression analysis, BMD remained significantly associated with body fat percentage (β −0.154, p = 0.01), lean mass (β 0.057, p = 0.016) and phosphate concentration (β 0.225, p = 0.05). In the second cohort, BMI was 31 ± 5.1 kg/m². In the multiple regression analysis, BMD remained significantly associated with lean mass (β 0.006, p = 0.03). Conclusion  The inverse correlation found between body fat and BMD in the first cohort indicates morbid obesity increases the risk of osteoporosis and we found a positive correlation with lean and fat mass before bariatric surgery and with lean mass after bypass surgery.     

Body composition and muscle strength as predictors of bone mineral density in Crohn’s disease

Compromised skeletal status is a frequent finding in patients with Crohn’s disease (CD), leading to increased fracture risk. Low body weight is associated with bone mineral density (BMD) in CD, although the relative importance of its components, lean and fat mass, is unclear. Muscle strength is also a predictor of BMD in nondiseased populations; however, its association with bone in CD is unknown. We examined the independent effects of body composition and muscle strength on regional and whole-body BMD in a cohort of CD patients. Sixty men and women, aged 22–72 years, with disease duration of 13 ± 7 years, underwent scanning of the spine, hip, forearm, and whole-body BMD by dual-energy X-ray absorptiometry (DXA). Lean tissue, appendicular muscle mass (AMM), and fat mass were derived by DXA and grip strength by dynamometry. Medical history, medication usage, clinical variables, and nutritional intake were obtained by questionnaire. Prevalence of osteopenia and osteoporosis was 32 and 17%, respectively, with osteopenia more common at the hip and osteoporosis more common at the spine. In multiple regression analyses, AMM was an independent predictor of whole-body and regional BMD whereas lean mass was an independent predictor at the hip. Neither grip strength nor fat mass was independently associated with BMD. Of the components of body composition, muscle mass was strongly associated with regional and whole-body BMD. Preserving or augmenting muscle mass in this population may be a useful strategy to preserve BMD and thereby reduce fracture risk.     

Sister’s fracture history may be associated with perimenopausal bone fragility and modifies the predictability of fracture risk

Summary  The present study investigated the effects of first degree relatives’ fractures on fracture incidence after the menopause. Sister’s, but not other relatives’, wrist or hip fracture history was associated with increased risk of fragility fractures after the menopause. This suggests genetic predisposition to bone fragility among postmenopausal women. Objective  The aim of the present study was to investigate the association between first degree relatives’ fractures and perimenopausal bone fragility. Materials and methods  The study sample of 971 perimenopausal women was extracted from randomly selected Kuopio Osteoporosis Risk Factor and Prevention cohort and measured with dual X-ray absorptiometry in femoral neck (FN) in baseline (1989–1991), in 5 years (1994–97), and in 10 years (1999–2001). All low-trauma energy fractures during the 10-year follow-up were recorded based on self-reports and validated from medical records. First degree relatives’ history of life-time hip and wrist fractures (exact classification or trauma energy not specified) was questioned by postal inquiries. Results  There was a significant correlation between fathers’ vs. brothers’ and mothers’ vs. sisters’ fractures (p < 0.01 in Pearson bivariate correlations). Sister’s, but not mother’s, father’s, or brother’s wrist and hip fractures were associated with significantly lowered 10-year fragility fracture-free survival rate (HR = 0.56, p = 0.006). Sisters’ or other relatives’ fractures were not associated with FN bone loss rate or bone mineral density (BMD) in the follow-up measurements (p = NS in ANCOVA). The predictive power of BMD for fragility fractures differed according to sisters’ fracture history: Baseline FN T score predicted fracture-free survival only among women without sisters’ fracture history (HR 0.62, p < 0.001 vs. women with sisters’ fracture in Cox regression). Conclusions  In conclusion, sisters’ fracture history is associated with 10-year fracture-free survival in perimenopausal women but not with BMD or its changes. Predictability of fragility fracture risk with BMD may depend on sister’s fracture history. This may indirectly suggest genetic predisposition to bone fragility independently of BMD.     

Concentric and eccentric isokinetic resistance training similarly increases muscular strength, fat-free soft tissue mass, and specific bone mineral measurements in young women

Summary Women participated in 5 months of unilateral concentric (n = 37) or eccentric (n = 33) isokinetic resistance training of the legs and arms. Limb muscular strength increased as did total body, leg, and arm fat-free soft tissue mass, total body BMC, hip BMD, and forearm BMC and BMD. Isokinetic training benefits bone mineral acquisition. Introduction and hypothesis Isokinetic resistance training (IRT) is osteogenic; however, it is not known if concentric or eccentric modalities of IRT produce differential effects on bone. We tested our hypothesis that high-load eccentric versus concentric mode of IRT would produce greater increases in muscular strength, fat-free soft tissue mass (FFSTM), bone mineral density (BMD) and content (BMC) in trained legs and arms. Methods Participants were randomized to 5 months of concentric (n = 37) or eccentric (n = 33) training. The non-dominant leg and arm were used during training; dominant limbs served as controls. Muscular strength was measured with an isokinetic dynamometer; body composition was measured by dual-energy X-ray absorptiometry. Results Muscular strength of the concentrically and eccentrically trained leg (18.6%; 28.9%) and arm (12.5%; 24.6%) significantly increased with training. Gains in total body (TB) BMC (p < 0.05) and, in the trained limbs, total proximal femur BMD (p < 0.05) and total forearm BMD (p < 0.05) and BMC (p < 0.05) occurred in both groups. FFSTM increased for the TB and trained leg and arm (all p < 0.001) in both modes. Conclusion Regardless of the mode, high-intensity, slow-velocity IRT increases muscular strength and FFSTM of trained limbs and imparts benefits to TB BMC and site-specific BMD and BMC in young women.     

Bone mineral density measurement in puerperal women as a predictor of persistent osteopenia

The clinical value of bone mineral density (BMD) measurement in puerperal women is uncertain. Our aim was to examine the effectiveness of BMD measurement in puerperal women for identification of persistent osteopenia and osteoporosis. We addressed cross-sectional and longitudinal changes in BMD, assessed using dual-energy X-ray absorptiometry (DXA), in a postpartum female cohort from a single center in Japan. We measured BMD of the lumbar spine (L2–L4) with DXA in 2,436 puerperal women within 7 days of delivery (study 1). For 210 of the women, the BMD was measured again after 5–10 years (study 2). In study 1, 8 (0.3%) of the women were osteoporotic, 37 (17.0%) were osteopenic, and 2,013 (82.6%) were normal. In study 2, 27 (71.1%) of the 38 osteoporotic or osteopenic women identified in the puerperal scan were still osteopenic at the scan after 5–10 years. Over the same period, only 7 (4.1%) of 172 initially normal women became osteopenic. The mean of the BMD change per year was 0.15 ± 0.82%/year. Osteopenia was associated with a significantly lower body weight and body mass index at puerperium and after 5–10 years compared to normal women. The multiple regression analysis showed that BMD at the first scan negatively contributed and body weight changes between the scans positively significantly contributed to the BMD changes per year. Puerperal BMD remained static over the subsequent 5–10 years. If the women have a low BMD at this stage of their reproductive life, it tends not to improve over this time. Perhaps identification of this at-risk group may lead to effective interventions to reduce fracture risk in later life.     

The BPAQ: a bone-specific physical activity assessment instrument

Summary  A newly developed bone-specific physical activity questionnaire (BPAQ) was compared with other common measures of physical activity for its ability to predict parameters of bone strength in healthy, young adults. The BPAQ predicted indices of bone strength at clinically relevant sites in both men and women, while other measures did not. Introduction  Only certain types of physical activity (PA) are notably osteogenic. Most methods to quantify levels of PA fail to account for bone relevant loading. Our aim was to examine the ability of several methods of PA assessment and a new bone-specific measure to predict parameters of bone strength in healthy adults. Methods  We recruited 40 men and women (mean age 24.5). Subjects completed the modifiable activity questionnaire, Bouchard 3-day activity record, a recently published bone loading history questionnaire (BLHQ), and wore a pedometer for 14 days. We also administered our bone-specific physical activity questionnaire (BPAQ). Calcaneal broadband ultrasound attenuation (BUA) (QUS-2, Quidel) and densitometric measures (XR-36, Norland) were examined. Multiple regression and correlation analyses were performed on the data. Results  The current activity component of BPAQ was a significant predictor of variance in femoral neck bone mineral density (BMD), lumbar spine BMD, and whole body BMD (R² = 0.36–0.68, p < 0.01) for men, while the past activity component of BPAQ predicted calcaneal BUA (R² = 0.48, p = 0.001) for women. Conclusions  The BPAQ predicted indices of bone strength at skeletal sites at risk of osteoporotic fracture while other PA measurement tools did not.     

Nitrate use and changes in bone mineral density: the Canadian Multicentre Osteoporosis Study

Summary  Nitrates may have beneficial effects on bone. To determine if nitrates were associated with increased bone mineral density (BMD), we conducted a secondary analysis using data from subjects in a prospective study. Subjects reporting nitrate use had increased BMD compared with non-users, confirming that nitrates have positive BMD effects in women and men. Introduction  Prior studies suggest positive associations between nitrates and bone. Methods  We used linear regression models, stratified by gender and adjusted for age, weight, and baseline differences, to determine the association between daily nitrate use and BMD among subjects participating in the Canadian Multicentre Osteoporosis Study. All results are reported as annualised percent change in BMD at the hip and spine among nitrate users compared to non-users. Results  We included 1,419 men (71 reported daily nitrate use) and 2,587 women (97 reported daily nitrate use). Male non-users had decreased hip BMD (−1.3%; 95% confidence interval [95%CI] = −1.6 to −1.1) and increased spine BMD (2.8%; 95%CI = 2.5 to 3.1). Male nitrate users had increased hip BMD (1.4%; 95%CI = 0.1 to 2.8) and spine BMD (4.5%; 95%CI = 3.2 to 5.7). Among women, non-users had decreased hip BMD (−1.9; 95%CI = −2.1 to −1.7) and increased spine BMD (2.1%; 95%CI = 1.9 to 2.4) whilst users had an increase in hip BMD (2.0%; 95%CI = 1.2 to 2.8) and spine BMD (4.1%; 95%CI = 3.4 to 4.9). Conclusion  Nitrate use is associated with increased BMD at the hip and spine in men and women.     

Effect of Roux-en Y Gastric Bypass on Bone Metabolism in Patients with Morbid Obesity: Mansoura Experiences

Background  Roux-en-Y gastric bypass (RYGBP) has been found to be the most efficient way to lose weight and maintain the weight loss in morbid obesity. However, with the formation of a new stomach and the modification of intestinal anatomy, there are significant changes on bone metabolism. The objectives of this study were to evaluate effects of weight loss on bone metabolism after Roux-en Y gastric bypass in patients with morbid obesity. Methods  Our study included 70 patients with morbid obesity; RYGB was done for all patients. Daily postoperative oral supplementation with 1,000 mg of calcium and 800 IU of vitamin D was done for each patient. Body weight (BW), body mass index (BMI), total body fat, total lean tissue mass, bone mineral content (BMC), bone mineral density (BMD), total bone area (TBA; using dual energy X-ray absorptiometry), serum calcium, parathyroid hormone (PTH), 25-OH vitamin D, 24-h urinary calcium, and bone-specific alkaline phosphatase (BSAP) were assessed preoperatively and 1 year after surgery. Results  In our study, females comprised 70% of cases. The mean age was 35 ± 8.8 years. One year after RYGB, BW decreased significantly from 132.8 ± 26.5 to 90.3 ± 17.3 kg (p = 0.001). BMI decreased significantly from 48 ± 7.3 to 32.6 ± 4.1 kg/m² (p = 0.001). BMC decreased significantly from 2,968.6 ± 71.4 to 2,700.8 ± 45.4 g (p = 0.001). BMD decreased significantly from 1.026 ± 0.03 to 1.22 ± 0.015 g/cm² (p = 0.001). TBA decreased significantly from 2,356.2 ± 35.4 to 2,216.3 ± 43.5 cm² (p = 0.001). Serum calcium, 24-h urinary calcium, and BSAP were not significantly decreased while 25-OH vitamin D and PTH were not significantly increased after surgery. Conclusions  From this study, it is shown that RYGBP operation gives very good results as regards reduction of body weight in morbidly obese patients. Postoperative supplementation with calcium and vitamin D partially corrects osteoporosis. Thus, these patients need periodic follow-up for BMD, PTH, calcium, serum vitamin D, and markers of bone resorption and formation specially postmenopausal female.     

Low bone mineral density at femoral neck is a predictor of increased mortality in elderly Japanese women

Summary  

This study aimed to determine whether low bone mineral density (BMD) at the femoral neck independently predicts all-cause mortality in elderly Japanese women. A prospective cohort study of 271 women aged 67–89 years was conducted. A Cox proportional hazard model was used to examine independent associations between BMD and total mortality. During a 12-year follow-up period, the mortality risk (as measured by hazard ratio [HR]) was significantly increased in the three categories of baseline BMD (diagnostic criteria of osteoporosis, tertile of BMD, and quartile of BMD). After adjusting for major potential confounding variables for mortality, significantly increased mortality risks were found in subjects with osteoporosis (HR = 2.17, p = 0.032), in subjects in the lowest tertile (HR = 2.57, p = 0.007), and in subjects in the lowest quartile (HR = 3.13, p = 0.014], respectively. Our findings suggest that preventive strategies should be considered to increase and maintain high BMD at the femoral neck in the elderly women not only to prevent hip fractures but also probably to reduce mortality risk.     

Racial difference in the correlates of bone mineral content/density and age at peak among reproductive-aged women

Summary  Racial/ethnic differences were observed in age at peak bone density and their correlates, with whites peaking at least 5 years earlier at the femoral neck than black and Hispanic women. Race-specific standards generated in this study could be useful when interpreting bone densitometry data in young women. Introduction  The influence of race/ethnicity on bone measurements has not been widely examined. This study identifies age and amount of bone accumulated at peak density and their correlates by race/ethnicity. Methods  Bone mineral content (BMC) and bone mineral density (BMD) of the spine and femoral neck were measured by dual X-ray absorptiometry in 708 white, black, and Hispanic reproductive-aged women. Race-specific nonlinear models were used to describe the relationship between age and bone measurements, after adjusting for body weight and height. Log-transformed bone measurements were used to determine predictors based on multiple linear regression. Results  Predictors, which were race and site specific, included age, age at menarche, body weight, height, months of depot medroxyprogesterone acetate use, weight-bearing exercise, and alcohol use. Women of all races gained BMC and BMD at the spine up to 30–33 years of age. BMC and BMD of the femoral neck peaked among white women earlier (≤16 years) than among blacks (BMC 22 years; BMD 21 years) and Hispanics (BMC 29 years; BMD 20 years). Conclusion  Age at peak bone mass and its correlates differ by race/ethnicity. Race-specific standards generated in this study could be useful when interpreting bone densitometry data in young women. This work was supported by the National Institute of Child Health and Human Development grants R01HD39883 and K24HD043659 awarded to ABB and General Clinical Research Centers (GCRC) program, National Center for Research Resources, NIH, M01RR000073.     

Changes in Bone Mineral, Lean Body Mass and Fat Content as Measured by Dual Energy X-ray Absorptiometry: A Longitudinal Study

Bone mineral density (BMD) and soft tissue composition were measured by dual energy X-ray absorptiometry (DXA) 3–4 years apart in 273 men and women aged 23–90. We found different rates of BMD loss in different skeletal regions. There were also different rates of BMD loss in different regions within the hip. Average rates of loss for male subjects 50 years of age and above for BMD total body were 0.1%/year and for femoral neck 1.5%/year, whereas lumbar spine (L2–L4) increased by 0.4%/year. Average rates of loss for female subjects 50 years of age and above for BMD total body were 0.0%/year, femoral neck 0.9%/year, and lumbar spine (L2–L4) 0.1%/year. Received: 28 November 1997 / Accepted: 26 July 1999     

Relation between fibroblast growth factor-23, body weight and bone mineral density in elderly men

Summary  We evaluated the relation between serum FGF23 and bone mineral density (BMD) in a community-based cohort of elderly men. There was a weak correlation between FGF23 and BMD, which was primarily dependent on body weight. Introduction  FGF23 is a hormonal factor produced in bone and regulates serum levels of phosphate (Pi) and vitamin D. FGF23 over-expression is associated with skeletal abnormalities, including rickets/osteomalacia. The relation between FGF23 and Bone Mineral Density (BMD) in the community remains unexplored. Methods  We employed a large, population-based cohort of 3014 Swedish men aged 69–80 years, without known renal disease. BMD was measured with dual X-ray absorptiometry (DXA) in the hip and lumbar spine. Serum intact FGF23 was analyzed with a two-site monoclonal ELISA. Results  There was a weak but significant correlation between FGF23 and BMD in femoral neck (r = 0.04, p < 0.05), femoral trochanter (r = 0.05, p = 0.004), total hip (r = 0.06, p = 0.0015) and lumbar spine (r = 0.07, p = 0.0004). The correlations remained significant when adjusting for biochemical covariates (Pi, calcium, PTH, 25(OH)D and renal function). However, the association became insignificant in all regions when adjusting for established confounding variables including age, height, weight and smoking. Further analysis confirmed a significant correlation between FGF23 and body weight (r = 0.13, p < 0.0001). Conclusions  The weak correlation between FGF23 and BMD in elderly male subjects is mainly due to an association between FGF23 and body weight. Therefore, FGF23 may not play a significant role in the hormonal regulation of BMD. Richard Marsell and Majd A. I. Mirza contributed equally to this work. Funding source: this study was supported by the Swedish Research Council, the Novo Nordisk Foundation, the Swedish Kidney Foundation and the Swedish Society of Medicine.     

Household Tobacco Smoke Exposure is Negatively Associated with Premenopausal Bone Mass

Subjects exposed to environmental tobacco smoke have been found to be at increased risk for several health problems. Whether exposure to passive tobacco smoke is associated with reduced bone mineral density (BMD) is unknown. In order to examine this, we measured BMD in 154 healthy premenopausal women (age range 40–45 years). BMD of the total hip, femoral neck, lumbar spine and total body was measured by dual-energy X-ray absorptiometry (DXA). Data were collected on exposure to household tobacco smoke from age 10 years to the present as well as on other lifestyle factors related to bone mass. We found that 67.5% of the subjects had a history of household tobacco smoke exposure. Subjects exposed to household tobacco smoke had a mean adjusted BMD that was significantly lower at the total hip (p= 0.021) and femoral neck (p= 0.018) compared with subjects who were not exposed. In addition, duration of household tobacco smoke exposure was negatively associated with BMD at the total hip (p = 0.010), femoral neck (p= 0.004), lumbar spine (p = 0.037) and total body (p = 0.031). Subjects exposed to household tobacco smoke for 15 years or more had mean adjusted BMD that was 4% lower at the total body, and more than 8% lower at the total hip, femoral neck and lumbar spine, compared with subjects who were not exposed. In conclusion, household tobacco smoke exposure during adolescence and young adulthood was found to be negatively associated with BMD at the total hip and femoral neck, and duration of exposure was negatively associated with BMD at the total hip, femoral neck, lumbar spine and total body in premenopausal women. Received: 17 December 2001 / Accepted: 16 February 2002