Project description:Previous studies have identified 63 single-nucleotide polymorphisms (SNPs) associated with bone mineral density (BMD) in adults. These SNPs are thought to reflect variants that influence bone maintenance and/or loss in adults. It is unclear whether they affect the rate of bone acquisition during adolescence. Bone measurements and genetic data were available on 6397 individuals from the Avon Longitudinal Study of Parents and Children at up to five follow-up clinics. Linear mixed effects models with smoothing splines were used for longitudinal modelling of BMD and its components bone mineral content (BMC) and bone area (BA), from 9 to 17 years. Genotype data from the 63 adult BMD associated SNPs were investigated individually and as a genetic risk score in the longitudinal model. Each additional BMD lowering allele of the genetic risk score was associated with lower BMD at age 13 [per allele effect size, 0.002 g/cm(2) (SE = 0.0001, P = 1.24 × 10(-38))] and decreased BMD acquisition from 9 to 17 years (P = 9.17 × 10(-7)). This association was driven by changes in BMC rather than BA. The genetic risk score explained ?2% of the variation in BMD at 9 and 17 years, a third of that explained in adults (6%). Genetic variants that putatively affect bone maintenance and/or loss in adults appear to have a small influence on the rate of bone acquisition through adolescence.
Project description:The implications of maternal gestational weight gain (GWG) and vitamin D status to neonatal bone health are unclear. We tested whether maternal 25-hydroxyvitamin D (25(OH)D) and GWG relate to neonatal bone mineral content (BMC) and bone mineral density (BMD). Healthy term appropriate for gestational age breastfed neonates (<i>n</i> = 142) and their mothers were recruited 24-36 h after delivery and followed at 1.0 ± 0.5 month. At birth, obstetric data were collected and newborn serum 25(OH)D was measured. At 1 month, neonatal whole-body (WB) BMC, WB BMC relative to body weight (WB BMC/kg), lumbar spine BMC and BMD, maternal and neonatal 25(OH)D concentrations, and anthropometry were measured. Infant BMC and BMD between maternal 25(OH)D (<50, ≥50 nmol/L) and GWG (insufficient, adequate, and excessive) categories were compared. Maternal 25(OH)D was not related to infant whole-body BMC, BMC/kg, lumbar spine BMC, and BMD. Infants in the excessive maternal GWG category had greater (<i>p</i> = 0.0003) whole-body BMC and BMC/kg and lumbar spine BMC and BMD than inadequate GWG, and greater (<i>p</i> = 0.0063) whole-body BMC/kg and lumbar spine BMC and BMD than adequate GWG. These results suggest that maternal GWG, but not vitamin D status, modestly relates to bone mass in neonates.
Project description:The relationship between muscle strength and bone mineral content (BMC) and bone mineral density (BMD) is supposed from the assumption of the mechanical stress influence on bone tissue metabolism. However, the direct relationship is not well established in younger men, since the enhancement of force able to produce effective changes in bone health, still needs to be further studied. This study aimed to analyze the influence of muscle strength on BMC and BMD in undergraduate students. Thirty six men (24.9 ± 8.6 y/o) were evaluated for regional and whole-body composition by dual energy X-ray absorptiometry (DXA). One repetition maximum tests (1RM) were assessed on flat bench-press (BP), lat-pull down (LPD), leg-curl (LC), knee extension (KE), and leg-press 45° (LP45) exercises. Linear regression modelled the relationships of BMD and BMC to the regional body composition and 1RM values. Measurements of dispersion and error (R2adj and standard error of estimate (SEE)) were tested, setting ρ at ≤0.05. The BMD mean value for whole-body was 1.12±0.09 g/cm2 and BMC attained 2477.9 ± 379.2 g. The regional lean mass (LM) in upper-limbs (UL) (= 6.80±1.21 kg) was related to BMC and BMD for UL (R2adj = 0.74, p<0.01, SEE = 31.0 g and R2adj = 0.63, SEE = 0.08 g/cm2), and LM in lower-limbs (LL) (= 19.13±2.50 kg) related to BMC and BMD for LL (R2adj = 0.68, p<0,01, SEE = 99.3 g and R2adj = 0.50, SEE = 0.20 g/cm2). The 1RM in BP was related to BMD (R2adj = 0.51, SEE = 0.09 g/cm2), which was the strongest relationship among values of 1RM for men; but, 1RM on LPD was related to BMC (R2adj = 0.47, p<0.01, SEE = 44.6 g), and LC was related to both BMC (R2adj = 0.36, p<0.01, SEE = 142.0 g) and BMD (R2adj = 0.29, p<0.01, SEE = 0.23 g/cm2). Hence, 1RM for multi-joint exercises is relevant to BMC and BMD in young men, strengthening the relationship between force and LM, and suggesting both to parametrizes bone mineral health.
Project description:<h4>Background</h4>Maternal smoking during pregnancy is associated with short-term and also long-term harmful effects on offspring.<h4>Objective</h4>The aim of this study is to evaluate the associations of maternal smoking during pregnancy with offspring bone health at 18years old, and the role of birth weight and contemporaneous height, weight and body mass index (BMI) in this association. Data from the 1993 Pelotas Birth Cohort were analyzed using path analysis stratified by sex. Adolescents at 18 years old (N=1512 males, 1563 females). DXA-determined total body bone mineral density (BMD) and bone mineral content (BMC) were assessed at 18 years old.<h4>Results</h4>Each additional cigarette smoked during pregnancy was associated with a lower BMC by -4.20 g in males (95% CI -8.37; -0.05), but not in females [-2.22 g (95% CI -5.49; 1.04)]; weaker inverse associations were observed for BMD. This inverse association was explained by the influence of maternal smoking on birth weight and contemporaneous anthropometry, particularly height. A 1 kg higher birth weight was associated with a higher BMC by around 144 g in males and by around 186 g in females, and also with a higher BMD by around 0.019 g/cm(2) in males and by around 0.018 g/cm(2) in females, respectively.<h4>Conclusions</h4>Lifecourse analysis using path models has enabled to evaluate the role of mediators in the associations of maternal smoking during pregnancy and birth weight with bone mass in the offspring, thus generating improved understanding of the etiology of bone health and the importance of early life experiences.
Project description:exercise can reduce osteoporotic fracture risk by strengthening bone or reducing fall risk. Falls prevention exercise programmes can reduce fall incidence, and also include strengthening exercises suggested to load bone, but there is little information as to whether these programmes influence bone mineral density (BMD) and strength.to evaluate the skeletal effects of home (Otago Exercise Programme, OEP) and group (Falls Exercise Management, FaME) falls prevention exercise programmes relative to usual care in older people.men and women aged over 65 years were recruited through primary care. They were randomised by practice to OEP, FaME or usual care. BMD, bone mineral content (BMC) and structural properties were measured in Nottingham site participants before and after the 24-week intervention.participants were 319 men and women, aged mean(SD) 72(5) years. Ninety-two percentage of participants completed the trial. The OEP group completed 58(43) min/week of home exercise, while the FaME group completed 39(16) and 30(24) min/week of group and home exercise, respectively. Femoral neck BMD changes did not differ between treatment arms: mean (95% CI) effect sizes in OEP and FaME relative to usual care arm were -0.003(-0.011,0.005) and -0.002(-0.010,0.005) g cm(-2), respectively; P = 0.44 and 0.53. There were no significant changes in BMD or BMC at other skeletal sites, or in structural parameters.falls prevention exercise programmes did not influence BMD in older people. To increase bone strength, programmes may require exercise that exerts higher strains on bone or longer duration.
Project description:Inflammatory bowel disease (IBD) is an idiopathic disease that can impair bone metabolism. Low vitamin D status has been implicated in its progress. This study used interleukin (IL)-10 knockout (KO) mice, that develop an intestinal inflammation when housed in a non-sterile environment, to determine if supplementation with vitamin D3 throughout life could mitigate inflammation and attenuate the lower bone mineral content (BMC) and density (BMD), and bone strength. Female IL-10 KO mice were randomized 25 or 5000 IU vitamin D3/kg diet throughout pregnancy and lactation. At weaning, offspring received the same or opposite diet as their mother until age three months. Body weight growth was similar among groups within a sex. At three months of age, there were no differences in inflammation and gene expression in the colon of offspring. Male offspring exposed to continuous 25 IU vitamin D3/kg diet had lower (p < 0.001) colonic VDR expression and those exposed only to low vitamin D3 until weaning had higher serum IL-6. There were no differences in femur or vertebral BMC, BMD or bone strength. In summary, long-term exposure to vitamin D3 did not attenuate intestinal inflammation or preserve bone mineral or bone strength. Thus, supplementation with vitamin D3 does not exert anti-inflammatory effects in this mouse model that mimics human inflammatory bowel disease.
Project description:Abstract <h4>Objectives</h4> To investigate sex differences in bone mass including whole body (WB) bone mineral content (BMC), lumbar spine (LS) BMC and LS bone mineral density (BMD) during infancy. <h4>Methods</h4> This is a secondary analysis of data from a double-blinded randomized clinical trial (NCT00381914), in which healthy term breastfed infants were randomized to 1 of 4 doses of oral vitamin D supplementation (400−1600 IU/d) at 1 mo of age (+/− 2 wk). Serum 25-hydroxyvitamin D (25(OH)D) using liquid chromatography-tandem mass spectrometry, and BMC and BMD using dual-energy x-ray absorptiometry (Hologic) were measured at 1, 3, 6, 9, and 12 mo of age (+/- 2 wk). No effect of supplementation on BMC (WB and LS) and BMD (LS) was reported in the primary study. Infants (32 males (M), 31 females (F)) with baseline serum 25(OH)D ≥ 50 nmol/L, based on the Institute of Medicine's cutoff in support of bone health, were included in this secondary analysis. Differences between sexes over time in BMC and BMD were tested using mixed model repeated measures ANOVA accounting for the fixed effects of sex, time, and sex*time and the random effect of infant ID, with Tukey multiple comparison test. <h4>Results</h4> Infants were on average 39.5 ± 1.1 wk gestational age, with weight for age z-score of 0.40 ± 0.97 at birth. There were no differences between sexes in mineral accretion rates of the WB (M: 12.94 ± 8.83, F: 12.20 ± 7.71 g/mo; p = 0.36) and at the LS (M: 0.26 ± 0.28, F: 0.22 ± 0.31 g/mo; p = 0.33) between 1 to 12 mo of age, but M had higher overall WB BMC than F (166.16 ± 57.30 vs. 153.34 ± 50.06 g, p = 0.03). When adjusted for weight or length, no sex differences were observed over time in WB BMC per weight (M: 22.02 ± 2.29, F: 22.20 ± 2.27 g/kg; p = 0.58) and WB BMC per length (M: 2.47 ± 0.60, F: 2.34 ± 0.53 g/cm, p = 0.06). Similarly, when using the WB less head BMC measurement, no sex differences were observed (M: 84.80 ± 30.24, F: 78.41 ± 7.57 g; p = 0.07). In addition, LS BMC (M: 3.77 ± 1.34, F: 3.75 ± 0.22 g; p = 0.93) and LS BMD (M: 0.273 ± 0.051, F: 0.284 ± 0.054 g/m2; p = 0.10) did not vary by sex. <h4>Conclusions</h4> Sex differences in BMC in infancy, if any, are mostly driven by infant size. Based on BMC and accretion rates, sex-specific normative data do not appear required during infancy. <h4>Funding Sources</h4> Canadian Institutes of Health Research, Nutricia Research Foundation, and the Canadian Foundation for Innovation.
Project description:Weight loss is a public health concern in obesity-related diseases such as metabolic syndrome (MetS). However, restrictive diets might induce bone loss. The nature of exercise and whether exercise with weight loss programs can protect against potential bone mass deficits remains unclear. Moreover, compliance is essential in intervention programs. Thus, we aimed to investigate the effects that modality and exercise compliance have on bone mineral content (BMC) and density (BMD).We investigated 90 individuals with MetS who were recruited for the 1-year RESOLVE trial. Community-dwelling seniors with MetS were randomly assigned into three different modalities of exercise (intensive resistance, intensive endurance, moderate mixed) combined with a restrictive diet. They were compared to 44 healthy controls who did not undergo the intervention.This intensive lifestyle intervention (15-20 hours of training/week + restrictive diet) resulted in weight loss, body composition changes and health improvements. Baseline BMC and BMD for total body, lumbar spine and femoral neck did not differ between MetS groups and between MetS and controls. Despite changes over time, BMC or BMD did not differ between the three modalities of exercise and when compared with the controls. However, independent of exercise modality, compliant participants increased their BMC and BMD compared with their less compliant peers. Decreases in total body lean mass and negative energy balance significantly and independently contributed to decreases in lumbar spine BMC.After the one year intervention, differences relating to exercise modalities were not evident. However, compliance with an intensive exercise program resulted in a significantly higher bone mass during energy restriction than non-compliance. Exercise is therefore beneficial to bone in the context of a weight loss program.ClinicalTrials.gov NCT00917917.
Project description:Controversy exists concerning the effects of higher total protein intake (TPro) on bone health, which may be associated with reduced bone mineral density (BMD). However, whey protein (WP) may induce bone formation because of its basic component, milk basic protein.This study assessed the effects of WP supplementation, TPro, and change in TPro (postsupplementation - presupplementation) on BMD and bone mineral content (BMC; total body, lumbar spine, total femur, and femoral neck) in overweight and class I obese middle-aged adults following an exercise intervention.This analysis used data from a double-blind, randomized, placebo-controlled 36-wk WP supplementation trial, wherein participants consumed a 1.7-MJ (400-kcal) supplement (0, 20, 40, or 60 g WP/d) along with their otherwise unrestricted diet while participating in a resistance and aerobic exercise intervention (3 d/wk). TPro was the summation of WP and habitual dietary intakes (4-d food record). Statistical analyses for WP were based on group and bone data [n = 186, 108 women; mean ± SD age: 49 ± 8 y; body mass index (BMI; in kg/m2): 30.1 ± 2.8], whereas TPro was based on dietary and bone data (n = 113, 70 women; age 50 ± 8 y; BMI 30.1 ± 2.9).WP supplementation, regardless of dose, did not influence BMD or BMC following the intervention. By using a multiple linear regression model, TPro (expressed as g/d or g · kg-1 · d-1) and change in TPro (expressed as g/d) were not associated with responses over time in total or regional BMD or BMC. By using a cluster analysis approach [<1.0 (n = 41), 1.0-1.2 (n = 28), and ?1.2 g · kg-1 · d-1 (n = 44)], TPro was also not associated with responses in total or regional BMD or BMC over time.WP supplementation and total dietary protein intake did not negatively or beneficially influence bone quantity in overweight and obese adults during a 9-mo exercise intervention. This trial was registered at clinicaltrials.gov as NCT00812409.