Changes In Bone Mineral Content Research Articles

Calcium Intake and Bone Mineral Acquisition during the Pubertal Growth Spurt: Three-Year Follow-Up of the Kitakata Kids Health Study in Japan

Calcium intake during a growth spurt may influence bone mineral acquisition. However, no population-based cohort studies have examined the relationship between calcium intake and whole-body bone mineral acquisition in Japanese children. The present study investigated the relationship between calcium intake and whole-body bone mineral acquisition in community-dwelling children in a northeast region of Japan using dual-energy X-ray absorptiometry. The source population for the baseline survey comprised all school children in 4th through 6th grades (275 children; age range, 10-12 y) in the Shiokawa area of Kitakata City, Fukushima. We obtained complete information from 220 children (100 girls and 120 boys), and analyzed total body less head (TBLH) bone mineral content (BMC), TBLH areal bone mineral density (aBMD), and bone mineral apparent density (BMAD) as an estimate of volumetric bone density. The Food Frequency Questionnaire for the Prevention and Management of Osteoporosis was validated in a previous study and used to estimate dietary nutrient intake. At baseline, mean calcium intake was 641 mg/d in girls and 660 mg/d in boys. Calcium intake in boys showed a significant (p<0.05) relationship with TBLH BMC and TBLH aBMD at follow-up, and with changes in TBLH BMC, TBLH aBMD, and TB BMAD from baseline to follow-up. After adjusting for potential confounding factors including body weight, we found no significant relationships between calcium intake and bone mineral parameters. Further studies are needed to clarify whether calcium intake affects bone mineral acquisition during pubertal growth spurts in the Japanese population.

Prospective Changes in the Distribution of Movement Behaviors Are Associated With Bone Health in the Elderly According to Variations in their Frailty Levels.

Frailty is associated with poor bone health and osteoporosis, and physical activity (PA) is one of the best treatments for both pathologies in older adults. Nonetheless, because daily time is limited, how the time is distributed during the waking hours is critical. The waking hours are spent according to different movement behaviors: sedentary behaviors (SB), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA). The aim of this study was to use compositional data analyses to examine the effects of the change in movement behaviors on bone health during aging in older people, related to the changes in their frailty levels. We analyzed 227 older people aged 65 to 94 (125 women and 102 men) over a 4-year period. Movement behaviors were assessed using accelerometry. Both bone mineral density (BMD) and bone mineral content (BMC) were determined using bone densitometry. The Frailty Trait Scale was used to divide the sample by frailty level evolution during aging. The R statistical system was used for the compositional data analysis and, in addition, all models were adjusted for several covariates. The changes in the distribution of all movement behaviors within a waking hour period were significantly associated with spine and femoral neck BMD changes in the subgroup with a positive change in frailty level and spine BMC in the subgroup with no change in frailty level (p ≤ .05). Likewise, MVPA relative to the change in other movement behaviors was also associated in both subgroups with higher BMD and BMC, respectively, in the same body areas (p ≤ .05). No significant associations were found in the negative change in frailty level subgroup. Older people who achieved a positive change in frailty level during a 4-year period showed higher BMD changes compared to those with no changes or increases in their frailty level. Therefore, increasing MVPA relative to the change in the other movement behaviors during a 4-year period could perhaps produce bone health improvements in the elderly that do not worsen their frailty level. © 2020 American Society for Bone and Mineral Research.

Bone chemical composition changes in bird bones from laboratory exposure to saline lake conditions

The abundance of bird bones in archeological contexts of high salt is potentially impacted by salinization, which can affect bone preservation. We exposed wing elements (humeri, ulnae, and radii) of domestic chicken (Gallus gallus domesticus) to laboratory conditions simulating a saline lake substrate with overlaying saltwater for up to 32 weeks. Our analyses based on bone ashing and elemental concentration using ICP-OES are reported. The data provide useful taphonomic information regarding changes in bone mineral content, element concentrations, and element to phosphorus ratios of bird bones exposed to saline environments. Results showed that all exposed wing bones increased significantly in bone mineral content, which indicated that wing bones most likely became stronger. Overall, ionic concentrations of Ca2+, K+, Mg2+, Na+, P5+, Sr2+, and Si4+, except Fe3+, changed significantly among all wing bones with saline exposure. These changes in ion concentration took place in as little as 4 weeks. Element to phosphorus ratios provided insight into potential ionic substitutions between the bone and the saline substrate and solution exposure. The results from our study provide direct evidence that the chemical composition of bird bones deposited along saline lake shorelines quickly become altered.

Combined effects of physical activity and calcium on bone health in children and adolescents: a systematic review of randomized controlled trials.

A better understanding of the role of exercise and nutrition in bone health is significant for preventing osteoporosis. The aim of this review was to assess the combined effects of physical activity and calcium intake on improving bone mineral density in children and adolescents. A search of electronic databases (MedLine, ISI Web of Science, Science Direct) and the literature references were performed. Randomized controlled trials published between 1997 and 2017, evaluating the effect of both physical activity and calcium intake intervention on bone mineral density or bone mineral content among children aged 3-18years were selected. The Improved Jadad Rating Scale was used to assess the methodological quality of the included studies. Study characteristics were summarized in accordance with the review's PICO criteria. Changes in bone mineral content were detected at several different bone sites. A total of nine studies involving 908 participants were included in this review. The combined intervention of physical activity and calcium increased bone mineral in children and adolescents, especially when baseline calcium intake level was low and among participants on the stage of early puberty. Regular physical activity combined with high level of calcium intake is beneficial for bone health in young population. Further research is needed to evaluate the dose-response associations and long-term effects of the interaction between physical activity and calcium intake.

Handball practice on bone health of female adolescents: evaluation of an eight-month competitive period

A strategy to prevent bone loss diseases (i.e., osteoporosis) would be to enhance the increase of bone mass during childhood and adolescence. The purpose of this study was to compare bone mineral density (BMD) and bone mineral content (BMC) between female adolescent handball players and peers who did not play (control group), and to assess the changes in BMD and BMC after eight-months of competitive period. Fifty-eight female adolescents (12–17 years old) were allocated into two groups: handball players (HG: n = 27) and control group (CG: n = 31). BMC and BMD were measured using dual-energy X-ray absorptiometry, and z-scores were calculated. Sexual maturity, menarche, peak height velocity (PHV), sun exposure and calcium intake were assessed. At baseline, the handball players showed greater BMC and BMD than control group (p &lt; 0.05). These differences between groups disappeared after adjusting for weight, BMI, menarche and lean soft tissue. After competitive period, significant time-effects for BMC and BMD of total TBLH and lumbar spine (p &lt; 0.01) were observed in the handball players. HG increased BMC and BMD of total body and lumbar spine after eight-month. The Z-score analysis showed significant group effects with greater BMD of total body, lumbar spine, femur and hip than control group. The results showed that after eight-month competitive handball period, there was an increase in BMD of total body for handball players.

The LunHab project: Muscle and bone alterations in male participants following a 10day lunar habitat simulation.

What is the central question of this study? It is well established that muscle and bone atrophy in conditions of inactivity or unloading, but there is little information regarding the effect of a hypoxic environment on the time course of these deconditioning physiological systems. What is the main finding and its importance? The main finding is that a horizontal 10 day bed rest in normoxia results in typical muscle atrophy, which is not aggravated by hypoxia. Changes in bone mineral content or in metabolism were not detected after either normoxic or hypoxic bed rest. Musculoskeletal atrophy constitutes a typical adaptation to inactivity and unloading of weightbearing bones. The reduced-gravity environment in future Moon and Mars habitats is likely to be hypobaric hypoxic, and there is an urgent need to understand the effect of hypoxia on the process of inactivity-induced musculoskeletal atrophy. This was the principal aim of the present study. Eleven males participated in three 10day interventions: (i) hypoxic ambulatory confinement; (ii) hypoxic bed rest; and (iii) normoxic bed rest. Before and after the interventions, the muscle strength (isometric maximal voluntary contraction), mass (lean mass, by dual-energy X-ray absorptiometry), cross-sectional area and total bone mineral content (determined with peripheral quantitative computed tomography) of the participants were measured. Blood and urine samples were collected before and on the 1st, 4th and 10th day of the intervention and analysed for biomarkers of bone resorption and formation. There was a significant reduction in thigh and lower leg muscle mass and volume after both normoxic and hypoxic bed rests. Muscle strength loss was proportionately greater than the loss in muscle mass for both thigh and lower leg. There was no indication of bone loss. Furthermore, the biomarkers of resorption and formation were not affected by any of the interventions. There was no significant effect of hypoxia on the musculoskeletal variables. Short-term normoxic (10day) bed rest resulted in muscular deconditioning, but not in the loss of bone mineral content or changes in bone metabolism. Hypoxia did not modify these results.

The Relationship between Bone Mineral Accrual and Changes of Body Composition in Competitive Girl Runners

Low bone density is a complication of a long-term strict weight control during adolescence in women. PURPOSE: To assess whether decrease in percent body fat (%BF) is associated with an impaired bone mineral accrual in girl runners. METHODS: Consecutive 22 freshmen girl runners (15y/o, 158cm, 45kg) during 7 years in competitive high school teams were evaluated over 2 years of training. DXA was performed at the preparatory phase (baseline) and repeated after 23 ± 2 months (follow-up). The runners were divided into 2 groups; negative (DEC, n=11) or positive (GAIN, n=11) changes of %BF (Δ%BF) during the period. The effect of the period and the group on the changes in bone mineral content (BMC) and density (BMD) of total body less head and z-score were analyzed by 2-way repeated measures ANOVA. As for lean soft tissue mass (LSM) and fat mass (FM), paired t-test was used to compare between baseline and follow-up. Bivariate correlation analysis was used to examine the relationship between bone mineral accrual (ΔBMC and ΔBMD) and Δ%BF as well as the changes of FM (ΔFM) and LSM (ΔLSM). Written informed consent was obtained from the runners and their parents. P<0.05 was considered as statistically significant. RESULTS: %BF changed from 17.4 to 14.3 (DEC) and 15.0 to 18.4 % (GAIN). The period had significant effects on BMC, BMD, and z-score without interactions. Contrast showed significant increases in those variables, while the group of Δ%BF had no significant effect, indicating the values of DEC and GAIN were similarly increased; 1.57 to 1.64 and 1.66 to 1.77 kg, 0.98 to 1.00 and 1.00 to 1.03 g/cm2, and -0.25 to -0.20 and 0.04 to 0.22, respectively. The DEC runners gained LSM (34.2 to 36.1 kg) and reduced FM (7.7 to 6.4 kg) significantly, while the GAIN runners significantly increased FM (6.9 to 9.0 kg) without LSM change (36.6 to 37.0 kg). Neither Δ%BF nor ΔFM, but ΔLSM was significantly correlated with ΔBMC (r=0.45) and ΔBMD (r=0.55). CONCLUSIONS: Bone mineral was equally accrued among the runners of which %BF increased or decreased, where the accretion was associated with LSM gain. Competitive distance runners would develop leanness by not only losing FM but also gaining LSM (i.e., skeletal muscle) along with long-term exercise training. This would ameliorate an impairment of bone mineral acquisition by strict weight control.

Pilot Data Suggest Negative Change In Bone Mineral Content Is Related To Self-report Musculoskeletal Injury In Infantry Marines

Pilot Data Suggest Negative Change In Bone Mineral Content Is Related To Self-report Musculoskeletal Injury In Infantry Marines

Dietary Calcium Intake and Bone Loss Over 6 Years in Osteopenic Postmenopausal Women.

Calcium intakes are commonly lower than the recommended levels, and increasing calcium intake is often recommended for bone health. To determine the relationship between dietary calcium intake and rate of bone loss in older postmenopausal women. Analysis of observational data collected from a randomized controlled trial. Participants were osteopenic (hip T-scores between -1.0 and -2.5) women, aged >65 years, not receiving therapy for osteoporosis nor taking calcium supplements. Women from the total cohort (n = 1994) contributed data to the analysis of calcium intake and bone mineral density (BMD) at baseline, and women from the placebo group (n = 698) contributed data to the analysis of calcium intake and change in BMD. BMD and bone mineral content (BMC) of the spine, total hip, femoral neck, and total body were measured three times over 6 years. Mean calcium intake was 886 mg/day. Baseline BMDs were not related to quintile of calcium intake at any site, before or after adjustment for baseline age, height, weight, physical activity, alcohol intake, smoking status, and past hormone replacement use. There was no relationship between bone loss and quintile of calcium intake at any site, with or without adjustment for covariables. Total body bone balance (i.e., change in BMC) was unrelated to an individuals' calcium intake (P = 0.99). Postmenopausal bone loss is unrelated to dietary calcium intake. This suggests that strategies to increase calcium intake are unlikely to impact the prevalence of and morbidity from postmenopausal osteoporosis.

Longitudinal changes in bone mineral density, bone mineral content and bone area at the lumbar spine and hip in postmenopausal women, and the influence of abdominal aortic calcification

Longitudinal studies often report that spine bone mineral density (BMD), measured by DXA, is stable in older adults, which has been attributed to osteophyte development and the presence of aortic calcification. A decline in projected spine area as a result of loss of intervertebral disc height might also contribute to higher BMD. We utilised data from 297 postmenopausal women (mean 73 years) who had DXA measurements of the lumbar spine, total hip and femoral neck 5 years apart, and abdominal aortic calcification scoring from vertebral morphometry. BMD declined by −4.4% at the total hip and −3.9% at the femoral neck (p < 0.001), but did not change at the spine (−0.5%, p = 0.12). In contrast, bone mineral content (BMC) declined by −4.0% at the total hip, −2.5% at the femoral neck and −1.7% at the spine (all p < 0.001). Bone area increased by 0.5% at the hip and 1.6% at the femoral neck but declined by −1.2% at the spine (all p < 0.001). 43% of the cohort had abdominal aortic calcification (AAC) present at baseline. The presence of AAC at baseline was not related to changes in BMD or BMC at the total hip or femoral neck, nor to BMD at the spine. However, women with AAC present had a smaller loss of BMC at the spine than those without (−0.8% versus −2.4%, p = 0.03). AAC score increased more over 5 years among those with AAC at baseline than those without (0.28 versus 0.16, p = 0.036). Thus, the stability of spine BMD is the result of both a loss of projected bone area (as a result of intervertebral disc changes and/or a decrease in projected area of the vertebral bodies) and the effects of aortic calcification. Future clinical trials should consider assessing changes in spine BMC as a more informative index of spine mineral status.

Dieting is associated with reduced bone mineral accrual in a longitudinal cohort of girls

BackgroundPeak bone mass accrual occurs during adolescence, a time when dieting and related eating behaviors are common. Impaired bone mineral accrual is a known consequence of eating disorders in adolescents, but the effects of subclinical dieting behaviors on bone mineral content (BMC) have not been described in this age group. The goal of this analysis was to determine whether dieting behavior in preadolescence and adolescence is associated with bone mineral accrual in adolescent girls.MethodsNon-Hispanic white girls (n = 139) were followed in a longitudinal cohort study. BMC was assessed at ages 9 and 15y. Dieting to lose weight was reported every 2 years, and dietary restraint and disinhibition, eating attitudes, weight concerns, and body esteem were assessed at age 11y. Girls were classified as “early dieters” if they first dieted by age 11y (31.7%), “adolescent dieters” if they first dieted after 11y (46.8%), or non-dieters if they did not report dieting by 15 y (21.6%). The effect of dieting related variables on BMC at 15y and change in BMC from 9 to 15y was assessed using linear regression, controlling for height, weight, BMI, physical activity, and pubertal status.ResultsGirls who first reported dieting to lose weight by age 11y had a 4.2% lower bone mineral accrual across adolescence (p = 0.02) and 3.1% lower BMC at age 15y (p = 0.005) than girls who first reported dieting after 11y or not at all. Number of weight control behaviors used, dietary restraint, and weight concerns were also negatively associated with BMC (p < 0.05).ConclusionsDieting behavior in preadolescence is associated with reduced bone mineral accrual. Strategies to promote optimal bone development should include prevention of dieting.Trial registrationClinicaltrials.gov NCT03342430, November 17, 2017. Retrospectively registered.

Calcium and phosphorus loss from laying hen bones autoclaved for tissue removal

Standard procedure for most conventional bone assays rely on bones being free of attached muscle or integumentary tissue. Use of an autoclave for bone cleaning is advantageous, as parts may be cleaned afterward by peeling the muscle away as opposed to tediously scrapping muscle tissue from the bone by hand. However, autoclave use for tissue removal has not been validated and published studies typically do not specify the cleaning method. One concern is that autoclave usage could cause mineral leaching out of the bone. The objective was to determine any change in bone mineral content as a result of autoclaving bone samples to remove muscle tissue. Ten pairs of frozen chicken legs were randomly selected and thawed from 72-wk-old W36 hens. Right legs were autoclaved at 121°C for 25 min in individual trays. Left legs were thawed and cleaned by hand. The tibia, meat, and exudate were collected from each leg. Cleaned bones were placed in a soxhlet to extract the fat for 30h and ashed at 600°C for 8h. Bone and muscle samples underwent microwave digestion in 10mL of 70% nitric acid. Digested samples were analyzed for calcium using a flame atomic absorption spectrophotometer. Phosphorus was determined by a colorimetric assay measuring phosphate ion complexes. Statistical analysis was completed by paired t-tests. We found no significant calcium (P = 0.6319) or phosphorus (P = 0.1698) loss from bones autoclaved as compared with bones that were hand cleaned. This study provides evidence that affirms that the use of the autoclave on bones is a suitable method for tissue removal from the leg bones of adult laying hens.

Three-monthly bolus vitamin D supplements (1000 vs 400 IU/day) for prevention of bone loss in children with difficult-to-treat nephrotic syndrome: a randomised clinical trial

ABSTRACTBackground: Nephrotic syndrome (NS) in children is one of the most common chronic diseases with a remitting and relapsing course. Glucocorticoids (prednisolone) are considered to be the treatment of choice but are associated with osteoporosis. There are no uniform consensus guidelines regarding the optimum dose of calcium and vitamin D for osteoprotection. Some authorities suggest a daily dose of 1000 IU vitamin D for children for osteoprotection, while others suggest a daily dose of 400 IU.Objectives: To compare the efficacy of three-monthly bolus vitamin D supplementation (1000 vs 400 IU/day) to prevent bone loss in children with difficult-to-treat NS (DTNS).Methods: In this parallel-group, open-label, randomised clinical trial, 60 children aged 1–18 years with DTNS [37 with frequently relapsing NS (FRNS), 13 steroid-dependent NS (SDNS) and 10 steroid-resistant NS (SRNS)] were enrolled and block randomised in a 1:1 allocation ratio to receive 1000 IU/day vitamin D (Group A, n = 30) or 400 IU/day (Group B, n = 30), administered as three-monthly bolus supplemental doses. In Group A, vitamin D (cholecalciferol, Calcirol®sachet) was administered as a stat dose of 90,000 IU every three months (calculated for a period of three months at 1000 IU/day). In Group B, vitamin D (cholecalciferol) was administered as a stat dose of 36,000 IU every three months (calculated for a period of three months at 400 IU/day). The proportionate change in bone mineral content (BMC) was studied by dual energy X-ray absorptiometry (DEXA) scan in both groups after vitamin D supplementation by analysing the values of BMC obtained 12 months apart (baseline vs. after 12 months).Results: Sixty children were randomised to receive vitamin D at a dose of either 1000 IU/day (Group A) or 400 IU/day (Group B). The two groups were comparable in their baseline clinical and laboratory parameters (including BMC and bone mineral density (BMD)). The distribution of the three types of NS (FRNS, SDNS and SRNS) was also comparable in both groups. In Group A, there were 19, 6 and 5 children with FRNS, SDNS and SRNS, respectively, and in Group B there were 18, 7 and 5 children with FRNS, SDNS and SRNS, respectively. The proportionate change in BMC was not significantly different between the two groups (median proportionate change in BMC in Group A 13.36% vs 11.59% in Group B, p = 0.22). Overall, BMC increased in both groups (96.7% in each). Only one (3.3%) patient in each group exhibited bone loss. None of the patients had a urinary calcium:creatinine ratio >0.2 at the end of the study.Conclusion: Three-monthly bolus vitamin D dosing regimens administered either as 1000 or 400 IU/day prevent bone loss in children with DTNS who require long-term steroids. Overall, three-monthly bolus supplemental prophylactic vitamin D, either 1000 or 400 IU/day, would seem to be an effective strategy for preventing bone loss in children with DTNS, as evidenced by the extremely low rates of bone loss (3.3% in each group), and is useful for delivering optimal care to children with DTNS. However, since this study was designed as an equivalence trial and not a superiority trial, further studies are required to demonstrate the superiority of the former regimen over the latter.Abbreviations: BMC, bone mineral content; BMD, bone mineral density; DEXA, dual energy X-ray absorptiometry; DTNS, difficult-to-treat nephrotic syndrome; FRNS, frequently relapsing nephrotic syndrome; IFRNS, infrequently relapsing nephrotic syndrome; iPTH, intact parathyroid hormone; NS, nephrotic syndrome; SDNS, steroid-dependent nephrotic syndrome; SRNS steroid-resistant nephrotic syndrome.

Bone accrual in oligo-amenorrheic athletes, eumenorrheic athletes and non-athletes.

Mechanical loading improves bone mineral density (BMD) and strength while decreasing fracture risk. Cross-sectional studies show that exercise advantage is lost in oligo-amenorrheic athletes (OA). Longitudinal studies examining the opposing effects of exercise and hypogonadism on bone are lacking in adolescents/young adults. Evaluate differences in bone accrual over 12 months in OA, eumenorrheic athletes (EA) and non-athletes (NA). We hypothesized that bone accrual would be lower in OA than EA and NA, with differences most pronounced at non-weight bearing trabecular sites. 27 OA, 29 EA, and 22 NA, 14-25 years old, completed 12-months of the prospective study. Athletes were weight-bearing endurance athletes. Subjects were assessed for areal BMD and bone mineral content (BMC) using DXA at the femoral neck, total hip, lumbar spine and whole body (WB). Failure load (a strength estimate) at the distal radius and tibia was assessed using microfinite element analysis of data obtained via high resolution peripheral quantitative computed tomography (HRpQCT). The primary analysis was a comparison of changes in areal BMD, BMC, and failure load across groups over 12-months at the respective sites. Groups did not differ for baseline age, height or BMI. Percent body fat was lower in both OA and EA compared to NA. OA attained menarche later than EA and NA. Over the follow-up period, OA gained 1.9 ± 2.7 kg of weight compared to 0.5 ± 2.4 kg and 0.8 ± 2.3 kg in EA and NA respectively (p = 0.09); 39% of OA resumed menses. Changes in BMD, BMD Z-scores, and tibial failure load over 12-months did not differ among groups. At follow up, EA had higher femoral neck, hip and WB BMD Z-scores than NA, and higher hip BMD Z-scores than OA (p < 0.05) after adjusting for covariates. At follow-up, radial failure load was lower in OA vs. NA, and tibial failure load lower in OA and NA vs. EA (p ≤ 0.04 for all). Change in weight and fat mass were associated with changes in BMD measures at multiple sites. Despite weight gain and menses recovery in many OA during follow-up, residual deficits persist without catch-up raising concerns for suboptimal peak bone mass acquisition.

Changes in body composition, bone metabolism, strength, and skill-specific performance resulting from 16-weeks of HIFT.

High Intensity Functional Training (HIFT) is a training modality, characterized by multimodal exercises performed at high-intensity. Little is known about the training adaptations that occur as a prolonged training program. The purpose of this study was to examine changes in body composition, bone metabolism, strength, and skill-specific performance over 16-weeks of HIFT. Twenty-six recreationally active adult males (n = 9; 34.2 ± 9.1 y; 91.5 ± 17.7 kg; 178.5 ± 5.4 cm) and females (n = 17 = 36.4 ± 7.9 y; 91.5 ± 17.7 kg; 162.9 ± 7.0 cm) completed pre and post training assessments of body composition (Dual-Energy X-Ray Absorptiometry) and performance measures. Performance was assessed using three HIFT workouts (WOD 1–3) to assess strength, skill, and metabolic performance. Aside from the body composition measurements, all assessments were carried out at the local training facility. Training included participation in HIFT a minimum of twice a week for 16-weeks. Repeated measures analysis of variance revealed a significant gender x time interaction in Bone Mineral Content (BMC) (p = 0.027), where improvements favored women (1.0% ± 1.1%, p = 0.004) over men (-0.1% + 0.8%, p = 0.625). Further, region-specific analysis indicated that women (2.5% ± 3.0%, p < 0.005) experienced greater improvements in the trunk compared to men (-0.3% ± 1.8%, p = 0.621), while changes in leg BMC were comparable between women (0.8% ± 1.0%, p < 0.001) and men (0.3% ± 0.6%, p < 0.001). Although no other interactions were observed, significant performance improvements were noted for all participants in WOD 1 (18.3% ± 16.8%), absolute 5RM (14.4% ± 9.7%), relative 5RM (15.4% ± 9.2%), WOD 2 (5.7% ± 6.5%), and WOD 3 (–17.3% ± 14.7%). These data indicate that 16-weeks of HIFT resulted in positive outcomes in strength, metabolic conditioning performance, and body composition.

FGF21 decreases body weight without reducing food intake or bone mineral density in high-fat fed obese rhesus macaque monkeys.

Administration of FGF21 and FGF21 analogues reduce body weight; improve insulin sensitivity and dyslipidemia in animal models of obesity and in short term clinical trials. However potential adverse effects identified in mice have raised concerns for the development of FGF21 therapeutics. Therefore, this study was designed to address the actions of FGF21 on body weight, glucose and lipid metabolism and importantly its effects on bone mineral density (BMD), bone markers, and plasma cortisol in high-fat fed obese rhesus macaque monkeys. Obese non-diabetic rhesus macaque monkeys (five males and five ovariectomized (OVX) females) were maintained on a high-fat diet and treated for 12 weeks with escalating doses of FGF21. Food intake was assessed daily and body weight weekly. Bone mineral content (BMC) and BMD were measured by DEXA scanning prior to the study and on several occasions throughout the treatment period as well as during washout. Plasma glucose, glucose tolerance, insulin, lipids, cortisol, and bone markers were likewise measured throughout the study. On average, FGF21 decreased body weight by 17.6 ± 1.6% after 12 weeks of treatment. No significant effect on food intake was observed. No change in BMC or BMD was observed, while a 2-fold increase in CTX-1, a marker of bone resorption, was seen. Overall glucose tolerance was improved with a small but significant decrease in HbA1C. Furthermore, FGF21 reduced concentrations of plasma triglycerides and very low density lipoprotein cholesterol. No adverse changes in clinical chemistry markers were demonstrated, and no alterations in plasma cortisol were observed during the study. In conclusion, FGF21 reduced body weight in obese rhesus macaque monkeys without reducing food intake. Furthermore, FGF21 had beneficial effects on body composition, insulin sensitivity, and plasma triglycerides. No adverse effects on bone density or plasma cortisol were observed after 12 weeks of treatment.

Behavioral Intervention in Adolescents Improves Bone Mass, Yet Lactose Maldigestion Is a Barrier.

Calcium intake during adolescence is important for attainment of peak bone mass. Lactose maldigestion is an autosomal recessive trait, leading to lower calcium intake. The Adequate Calcium Today study aimed to determine if a school-based targeted behavioral intervention over one year could improve calcium intake and bone mass in early adolescent girls. The school-randomized intervention was conducted at middle schools in six states over one school year. A total of 473 girls aged 10–13 years were recruited for outcome assessments. Bone mineral content (BMC) was determined by dual energy X-ray absorptiometry. Dietary calcium intake was assessed with a semi-quantitative food frequency questionnaire. Baseline calcium intake and BMC were not significantly different between groups. After the intervention period, there were no differences in changes in calcium intake and BMC at any site between groups. An unanticipated outcome was a greater increase in spinal BMC among lactose digesters than lactose maldigesters in the intervention schools only (12 months) (6.9 ± 0.3 g vs. 6.0 ± 0.4 g, p = 0.03) and considering the entire study period (18 months) (9.9 ± 0.4 vs. 8.7 ± 0.5 g, p < 0.01). Overall, no significant differences between the intervention and control schools were observed. However, lactose digesters who received the intervention program increased bone mass to a greater extent than lactose maldigesters.

EVALUATING THE THEORY OF BONE MECHANOREGULATION IN THE PHYSIOLOGICAL LOADING SCENARIO

In this paper, the theory of bone mechanoregulation under physiological loading was evaluated. The entire right tibiae of wild type (WT, [Formula: see text]) and parathyroid hormone (PTH, [Formula: see text]) treated C57BL/6J female mice were scanned using an in vivo [Formula: see text]CT imaging system at 14, 16, 17, 18, 19, 20, 21, and 22 weeks. The PTH intervention started from week 18 until week 22. Subject-specific finite element (FE) models were created from the [Formula: see text]CT images and physiological loading condition was defined in the FE models. The rates of changes in bone mineral content (BMC), bone mineral density (BMD), and bone tissue density (TMD) were quantified over 40 anatomical compartments across the entire mouse tibia. The resulting values were then correlated to the average 1st principal tensile strain ([Formula: see text]) and the strain energy density (SED) for every compartment at weeks 18, 20, and 22. It was found that: in both groups, [Formula: see text] had a minimal effect on the variability of [Formula: see text]BMC ([Formula: see text]); SED had a significant effect on the variability of [Formula: see text]BMC only in the WT group ([Formula: see text]); [Formula: see text] had a significant effect on the variability of [Formula: see text]BMD only in the PTH group ([Formula: see text]); SED had a significant effect on the variability of [Formula: see text]BMD in both groups ([Formula: see text]); neither SED nor [Formula: see text] had a significant effect on the variability of [Formula: see text]TMD ([Formula: see text]). These results are the first to reveal the mechanism of bone mechanoregulation in the physiological loading scenario.

Body Composition Changes in Severely Burned Children During ICU Hospitalization.

Prolonged hospitalization due to burn injury results in physical inactivity and muscle weakness. However, how these changes are distributed among body parts is unknown. The aim of this study was to evaluate the degree of body composition changes in different anatomical regions during ICU hospitalization. Retrospective chart review. Children's burn hospital. Twenty-four severely burned children admitted to our institution between 2000 and 2015. All patients underwent a dual-energy x-ray absorptiometry within 2 weeks after injury and 2 weeks before discharge to determine body composition changes. No subject underwent anabolic intervention. We analyzed changes of bone mineral content, bone mineral density, total fat mass, total mass, and total lean mass of the entire body and specifically analyzed the changes between the upper and lower limbs. In the 24 patients, age was 10 ± 5 years, total body surface area burned was 59% ± 17%, time between dual-energy x-ray absorptiometries was 34 ± 21 days, and length of stay was 39 ± 24 days. We found a significant (p < 0.001) average loss of 3% of lean mass in the whole body; this loss was significantly greater (p < 0.001) in the upper extremities (17%) than in the lower extremities (7%). We also observed a remodeling of the fat compartments, with a significant whole-body increase in fat mass (p < 0.001) that was greater in the truncal region (p < 0.0001) and in the lower limbs (p < 0.05). ICU hospitalization is associated with greater lean mass loss in the upper limbs of burned children. Mobilization programs should include early mobilization of upper limbs to restore upper extremity function.

Longitudinal effects of Parathyroid Hormone treatment on morphological, densitometric and mechanical properties of mouse tibia.

The use of Parathyroid Hormone (PTH) as bone anabolic is limited due to cost-benefit assessments. Preclinical studies evaluating the effects of PTH on bone have reported variable and often contradictory results. Here, we have applied a new approach using a combination of in-vivo longitudinal µCT, image processing techniques and finite element models to monitor early local changes in the whole tibia (divided in 40 compartments) and mechanical properties of female C57BL/6J mice treated with PTH 1-34, compared to controls. Compared with standard 3D bone morphometric analysis, our new approach allowed detection of much smaller and localised changes in bone mineral content (BMC) at very early time points (1 week vs 3 weeks with standard methods) and showed that changes do not occur uniformly over time and across the anatomical space. Indeed, in the PTH treated mice, significant changes in BMC were observed in the medial and posterior sectors of the proximal tibia, a week after treatment, and in the medial sector of the tibia midshaft region a week later (p < 0.05). By the third week, two thirds of the regions showed significantly higher values of BMC (p < 0.05). The effect of PTH on bone regional volume is similar to that on BMC, but there is almost no effect of PTH on bone tissue mineral density. The differences in estimated mechanical properties became significant after three weeks of treatment (p < 0.05). These results provide the first evidence of an early and localised PTH effect on murine bone, and show that our novel partitioning approach, compared to the standard evaluation protocol, allows a more precise quantification of bone changes following treatment, which would facilitate preclinical testing of novel mono- and/or combination therapies throughout the bone.