Lower Body Bone Mineral Content Research Articles

Variety of activity participation influences leg bone mineral content of pre-pubertal children with developmental coordination disorder

Limited participation in activities in children with developmental coordination disorder (DCD) may have a negative impact on bone mineral accrual. This study aimed to compare bone mineralization and activity participation patterns of pre-pubertal children with DCD and those with typical development, and to determine the relationship between activity participation patterns and bone mineralization in children with DCD. Fifty-two children with DCD (mean age = 7.5 years) and 61 children with typical development (mean age = 7.2 years) participated in the study voluntarily. Appendicular and total body bone mineral content (BMC) and bone mineral density (BMD) were assessed by a whole-body dual-energy X-ray absorptiometry scan. Activity participation patterns were assessed using the Children's assessment of participation and enjoyment (CAPE). Children with DCD had lower appendicular and total body BMCs and BMDs than children with typical development ( P < 0.05). Additionally, they had lower CAPE total activity and physical activity diversity and intensity scores ( P < 0.05). After accounting for the effects of bone age, sex, lean mass and fat mass, the total activity diversity score remained independently associated with leg BMC in children with DCD, explaining 5.5% of the variance ( P < 0.001). However, the physical activity diversity score was no longer associated with leg BMC ( P = 0.084). Diversity (variety) and intensity of activity participation and bone mineralization were lower in pre-pubertal children with DCD. Decreased total activity participation variety was a contributing factor to lower BMC in the legs of children with DCD.

Effect of cardiometabolic risk factors on the relationship between adiposity and bone mass in girls.

Background/ObjectiveChildhood obesity has been separately associated with cardiometabolic risk factors (CMR) and increased risk of fracture. However, both augmented and compromised bone mass have been reported among overweight/obese children. Metabolic dysfunction, often co-existing with obesity, may explain the discrepancy in previous studies. The aim of this study was to examine whether the relationship between adiposity and dual-energy x-ray absorptiometry (DXA) derived bone mass differed in young girls with and without CMR(s).Subjects/MethodsWhole body bone and body composition measures by DXA and measures of CMR (fasting glucose, high density lipoprotein cholesterol-HDL-C, triglyceride-TG, systolic and diastolic blood pressure, waist-circumference-WC) were obtained from 307, 9–12 year old girls. Girls with 1 or ≥ 2 CMR(s) were considered to be at risk (vs. no CMR). Multiple linear regression was used to test the relationship of total fat mass with total body bone mineral content (BMC) after controlling for height, lean mass, CMR risk, and other potential confounders.ResultsThere was a significant interaction between CMR risk and total body fat mass. When girls were stratified by CMR group, all groups had a significant positive relationship between fat mass and BMC (p<0.05), however girls with ≥ 2 CMRs had a lower BMC for a given level of body fat. Total body fat was not significantly related to bone mineral density (p>0.05).ConclusionFat mass has a positive relationship with BMC even after controlling for lean mass. However, the positive relationship of fat mass with BMC may be attenuated if multiple CMRs are present.

Associations between hypothalamic–pituitary–adrenal axis function and peak bone mass at 20 years of age in a birth cohort

In older adults, high-normal circulating cortisol levels are associated with lower bone mass, but relationships between hypothalamic–pituitary–adrenal axis function and peak bone mass in young adults have not been examined. We studied 411 male and 390 female participants in the Western Australia Pregnancy Cohort (Raine) Study. At 18years of age, participants underwent a Trier Social Stress Test (TSST) with measurement of plasma and salivary cortisol at baseline and at multiple time points after stress. Cortisol responses were classified as anticipatory responder (significant fall in cortisol during the test), reactive responder (significant increase) or non-responder. At 20years, total body bone mineral content (BMC) and density (BMD) were measured by DXA. In males, after adjustment for weight, height (for BMC and bone area only), alcohol and smoking, there was a significant inverse relationship between both plasma and salivary cortisol measured at baseline in the TSST and each of BMC and BMD, such that each additional 10% of salivary cortisol was associated with reductions of 6.9g (95% CI −11.7, −2.2) in BMC, and 1.8mg/cm2 (95% CI −3.3, −0.4) in BMD. Males classified as anticipatory responders in the TSST had 3.2% lower BMC (adjusted mean±SE: 3131±28 vs. 3233±18g, P=0.006) and 2.5% lower BMD (1108±9 vs. 1136±6mg/cm2, P=0.022) than reactive responders. In females, there were no significant relationships between baseline cortisol or TSST responses and BMC or BMD in covariate-adjusted analyses. We conclude that in young males (but not females), higher circulating cortisol at the baseline of the stress test and an anticipatory responder pattern on the TSST are associated with lower total body bone mass.

Assessment of bone mineral status in children with Marfan syndrome

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder with skeletal involvement. It is caused by mutations in fibrillin1 (FBN1) gene resulting in activation of TGF-β, which developmentally regulates bone mass and matrix properties. There is no consensus regarding bone mineralization in children with MFS. Using dual-energy X-ray absorptiometry (DXA), we evaluated bone mineralization in 20 children with MFS unselected for bone problems. z-Scores were calculated based on age, gender, height, and ethnicity matched controls. Mean whole body bone mineral content (BMC) z-score was 0.26 ± 1.42 (P = 0.41). Mean bone mineral density (BMD) z-score for whole body was −0.34 ± 1.4 (P = 0.29) and lumbar spine was reduced at −0.55 ± 1.34 (P = 0.017). On further adjusting for stature, which is usually higher in MFS, mean BMC z-score was reduced at −0.677 ± 1.37 (P = 0.04), mean BMD z-score for whole body was −0.82 ± 1.55 (P = 0.002) and for lumbar spine was −0.83 ± 1.32 (P = 0.001). An increased risk of osteoporosis in MFS is controversial. DXA has limitations in large skeletons because it tends to overestimate BMD and BMC. By adjusting results for height, age, gender, and ethnicity, we found that MFS patients have significantly lower BMC and BMD in whole body and lumbar spine. Evaluation of diet, exercise, vitamin D status, and bone turnover markers will help gain insight into pathogenesis of the reduced bone mass. Further, larger longitudinal studies are required to evaluate the natural history, incidence of fractures, and effects of pharmacological therapy. © 2012 Wiley Periodicals, Inc.

Total body and spinal bone mineral density across Tanner stage in perinatally HIV-infected and uninfected children and youth in PACTG 1045

To characterize total body bone mineral content (BMC) and total body and spinal bone mineral density (BMD) in perinatally HIV-infected and uninfected children/youth across puberty. HIV-infected (7-24 years) were randomly selected from six strata based on Tanner stage/protease inhibitor use. HIV-uninfected were frequency-matched by Tanner group and sociodemographic background to the HIV-infected. Dual-energy X-ray absorptiometry (DXA) measured BMC and BMD. Linear regression models tested differences in bone outcomes by HIV and the interaction of HIV by Tanner group (1-2, 3-4, 5). Models were performed separately by sex and adjusted for DXA scanner, race/ethnicity, height, age and lean body mass. HIV-infected (N = 236) and uninfected (N = 143) were comparable on sex and race/ethnicity. HIV-infected were slightly older (median 12.6 versus 11.9 years). In adjusted models, HIV-infected males had significantly lower total body BMC and total body and spinal BMD at Tanner 5, lower BMC at Tanner 3-4 and similar BMC and BMD at Tanner 1-2, compared to HIV-uninfected males. HIV-infected and uninfected girls did not differ significantly on any bone outcome, but there was a marginally significant interaction of HIV and Tanner group for spinal BMD. Kaletra/ritonavir was associated with lower BMC and total body BMD and nevirapine was associated with higher spinal BMD in a model with all HIV-infected. Perinatally HIV-infected males showed more evidence of lower bone density especially in the final stage of pubertal development than HIV-infected girls and they may be at increased risk for bone disease during adulthood.

Physical Benefits of Dancing for Healthy Older Adults: A Review

Dancing is a mode of physical activity that may allow older adults to improve their physical function, health, and well-being. However, no reviews on the physical benefits of dancing for healthy older adults have been published in the scientific literature. Using relevant databases and keywords, 15 training and 3 cross-sectional studies that met the inclusion criteria were reviewed. Grade B-level evidence indicated that older adults can significantly improve their aerobic power, lower body muscle endurance, strength and flexibility, balance, agility, and gait through dancing. Grade C evidence suggested that dancing might improve older adults' lower body bone-mineral content and muscle power, as well as reduce the prevalence of falls and cardiovascular health risks. Further research is, however, needed to determine the efficacy of different forms of dance, the relative effectiveness of these forms of dance compared with other exercise modes, and how best to engage older adults in dance participation.

Bone Changes in Adolescent Girls with Anorexia Nervosa

Purpose To clarify the effect of chronological age, height, lean tissue mass, and menstrual status on standard reported DXA (dual-energy x-ray absorptiometry) measures. Methods Growth and DXA data from a retrospective longitudinal cohort of 30 adolescent females with anorexia nervosa (AN) were examined. Areal bone mineral density (aBMD), total body bone mineral content (BMC) and total body bone area were measured and standardized for age, height, lean tissue mass, and total bone area. We then examined the changes in these parameters after 12 months of multidisciplinary treatment. Results The subjects had lower BMC and aBMD than the age- and height-matched reference population at baseline, there were further decreases in these parameters with treatment. BMC adjusted for lean tissue mass and bone area were normal at baseline and there was no significant change with treatment. Bone area adjusted for height was low at baseline and decreased despite treatment. Conclusion Our data suggest that the low age- and height-adjusted bone mineral content and bone mineral density in females with AN is secondary to poor bone growth leading to low bone area. These subjects had relatively normal bone mineral content for their bone size and lean tissue mass. Changes in bone size were proportional to changes in lean tissue mass.