Normal bone accretion and effects of nutritional disorders in childhood

Association of early-life famine exposure with low bone mass in adulthood

Famine exposure in early life has been found to have a long-term effect on metabolic diseases, but its effect on bone health was not clear. In this study, we found women, who suffered from famine exposure during their childhood or adolescence period, had significantly decreased BMD at several skeletal sites compared to the age-matched non-exposed groups. The risk of clinical fracture was also elevated in adolescence-exposed women.

PURPOSE

To investigate the correlation between famine exposure at certain stages and bone mass in adulthood.

METHODS

We enrolled participants born in 1943-1962 from the China Osteoporosis Prevalence Study (COPS), which were classified into three famine exposure groups according to their birth year: fetal-famine exposure (1959-1962, n = 1693), childhood-famine exposure (1949-1958, n = 5557), and adolescence-famine exposure (1943-1948, n = 1530). We also selected age-balanced non-exposed participants as the control groups for men and women separately. Bone mineral density (BMD) and vertebral fractures (VFs) were measured by dual X-ray absorptiometry (DXA) and X-ray, respectively. The associations of famine exposure in early life with BMD were assessed via multiple linear regression. Logistic regression was performed to examine the association of famine exposure in early life with fracture risk with adjustments for covariates.

RESULTS

In women, the childhood-exposed and adolescence-exposed groups had significantly decreased BMD at several skeletal sites compared to the age-matched non-exposed groups. No significant decreased BMD was found in the fetal-exposed groups compared to the non-exposed groups in both sexes. Multiple linear regression analysis showed that famine exposure during childhood and adolescence was negatively associated with BMD at the femoral neck after adjusting for covariates in women. The risk of clinical fracture was also elevated in adolescence-exposed women.

CONCLUSION

Famine exposure during early life especially childhood and adolescence is associated with decreased bone mass in adulthood in women but did not affect bone mass in men.

Osteocalcin and the Physiology of Danger

Bone biology has long been driven by the question as to what molecules affect cell differentiation or the functions of bone. Exploring this issue has been an extraordinarily powerful way to improve our knowledge of bone development and physiology. More recently, a second question has emerged: does bone have other functions besides making bone? Addressing this conundrum revealed that the bone-derived hormone osteocalcin affects a surprisingly large number of organs and physiological processes, including acute stress response. This review will focus on this emerging aspect of bone biology taking osteocalcin as a case study and will show how classical and endocrine functions of bone help to define a new functional identity for this tissue.

Interrelationships Between Morphometric, Densitometric, and Mechanical Properties of Teeth in 5-Month-Old Polish Merino Sheep

Interrelationships between morphological, densitometric, and mechanical properties of deciduous mandibular teeth (incisors, canine, second premolar) were investigated. To perform morphometric, densitometric, and mechanical analyses, teeth were obtained from 5-month-old sheep. Measurements of mean volumetric tooth mineral density and total tooth volume were performed using quantitative computed tomography. Microcomputed tomography was used to measure total enamel volume, volumetric enamel mineral density, total dentin volume, and volumetric dentin mineral density. Maximum elastic strength and ultimate force of teeth were determined using 3-point bending and compression tests. Pearson correlation coefficients were determined between all investigated variables. Mutual dependence was observed between morphological and mechanical properties of the investigated teeth. The highest number of positive correlations of the investigated parameters was stated in first incisor indicating its superior predictive value of tooth quality and masticatory organ function in sheep. Positive correlations of the volumetric dentin mineral density in second premolar with final body weight may indicate predictive value of this parameter in relation with growth rate in sheep. Evaluation of deciduous tooth properties may prove helpful for breeding selection and further reproduction of sheep possessing favorable traits of teeth and better masticatory organ function, leading to improved performance and economic efficiency of the flock.

The influence of dairy consumption, sedentary behaviour and physical activity on bone mass in Flemish children: a cross-sectional study

Background

This cross-sectional study aimed to look for an association in young children between whole body bone mineral content (BMC) and areal bone mineral density (aBMD) and dairy consumption as well as sedentary behaviour (SB) and physical activity (PA). Moreover, we investigated whether there was an interaction effect between dairy consumption and SB or PA on BMC and aBMD.

Methods

Healthy children (6-12 years) were recruited from primary schools. Body composition and whole body bone mass were measured with dual-energy X-ray absorptiometry (DXA), dairy consumption was assessed with a food frequency questionnaire (FFQ) and PA and SB with an accelerometer. In total, 272 children underwent a DXA scan. Complete FFQ data were available for 264 children and 210 children had matching data from accelerometry recordings. Regression analyses were used to study the associations between (1) BMC and aBMD and (2) dairy consumption, SB and PA, adjusting for age, gender, pubertal stage, height and body composition.

Results

Dairy consumption was positively associated with whole body BMC and aBMD (absolute value as well as z-score), after correction for relevant confounders. SB was negatively associated with aBMD z-score and light PA was positively associated with both BMC and aBMD z-score. No gender differences were found. Moreover, an interaction effect between vigorous PA (VPA) and dairy consumption on aBMD (z-score) and BMC z-score was found, indicating that children with both high VPA and high dairy consumption had higher values for BMC and aBMD of the whole body minus the head.

Conclusion

Already at young age, PA and dairy consumption positively influence whole body bone mass assessed by DXA. Moreover, this study indicates clearly that SB is negatively associated with whole body bone density. Promoting regular PA and sufficient dairy consumption in young children and limiting SB can be expected to positively influence their bone mass accumulation, which can help in the prevention of osteoporosis later in life.

Assessing the skeleton in children and adolescents with disabilities: avoiding pitfalls, maximising outcomes. A guide for the general paediatrician

Assessment of bone health of a young person with a severe disability is complex. Age of onset of disability, degree of physical limitation, nutritional status, calcium and vitamin D intake and pubertal progress all contribute to adult outcomes. Concomitant medical conditions may further adversely affect bone accrual. Bone quality, until growth is complete, must be interpreted in light of growth, height and puberty. For those children and adolescents who have disabilities where weight bearing is limited, satisfactory and reproducible measurements of bone density may be impossible to obtain. Fracture risk is dependent on the degree of immobilisation and on bone quality at any age. Meeting the goal of reducing extent and complications of adult osteoporosis is dependent upon an understanding of the nature and contribution of individual components of bone accrual, so that interventions can be appropriately targeted to optimise outcomes.

Psychosocial, environmental and behavioral factors associated with bone health in middle-school girls

The purpose of this study was to identify the psychosocial, environmental and behavioral factors associated with calcium intake, physical activity and bone health in a cohort of adolescent girls. Baseline data (N = 718 girls, mean age: 11.6 +/-0.4 years) from the Incorporating More Physical Activity and Calcium in Teens (IMPACT) study conducted in Texas, 2001-03, were utilized for the analyses. Hierarchical linear regression was used to examine the associations of interest. Confounders adjusted for included ethnicity, menarchal status, body mass index and lactose intolerance. Several psychosocial and behavioral factors were significantly associated with bone quality. These included knowledge of calcium content of foods (beta = 0.08, P = 0.016), self-efficacy toward consuming calcium-rich foods (beta = 0.16, P = 0.047), physical activity self-efficacy (beta = 0.20, P = 0.002), physical activity outcome expectations (beta = 0.5, P = 0.004), family encouragement to do physical activity (beta = 0.96, P = 0.027), friend engagement in physical activity (beta = 1.3, P = 0.001) and participation in sports teams (beta = 1.7, P < 0.001). Self-efficacy, social support and participation in sports teams appear to be strongly associated with bone health in adolescent girls. Future health education/health promotion programs need to address these factors for effective primary prevention of osteoporosis in this population.

Variations in admission practices for adolescents with anorexia nervosa: a North American sample

PURPOSE

The purpose of this study was to assess the variability in admission practices and medical inpatient care for adolescent patients with anorexia nervosa (AN).

METHODS

Participants consisted of members of the 2001-2003 Eating Disorder Special Interest Group from the Society for Adolescent Medicine who completed a structured telephone interview about their admission practices and patterns of inpatient care for teens with AN. Questions focused on admission threshold for heart rate (HR), percentage of ideal body weight (% IBW), and refeeding protocols. Case vignettes were used.

RESULTS

Of 95 eligible practitioners, 51 (53%) agreed to participate. Participants represented 25 American states, one Canadian province, and 45 different adolescent programs. The majority of physicians reported they would hospitalize an AN patient with HR <40 beats/min. The most common response for when to hospitalize based on % IBW was 75% IBW. There were no differences in admission practices based on number of years in practice, gender of physician, or practice setting. Regional differences in admission practices were noted, with physicians in the western United States less likely to admit patients with HR >or=40 beats per minute (p = .018). Physicians described 28 different methods of advancing a diet during an admission. Only 37% of physicians were aware of a standardized refeeding protocol in their institution.

CONCLUSION

This study indicates variability in admission criteria and refeeding practices and shows evidence of geographic variations of admission standards. These data provide a baseline for outcome trials investigating medical admissions for adolescents with AN.

Redefining osteoporosis treatment: Who to treat and how long to treat

Osteoporosis is a common disease that is associated with increased risk of fractures and serious clinical consequences. Bone mineral density (BMD) testing is used to diagnose osteoporosis, estimate the risk of fracture, and monitor changes in BMD over time. Combining clinical risk factors for fracture with BMD is a better predictor of fracture risk than BMD or clinical risk factors alone. Methodologies are being developed to use BMD and validated risk factors to estimate the 10-year probability of fracture, and then combine fracture probability with country-specific economic assumptions to determine cost-effective intervention thresholds. The decision to treat is based on factors that also include availability of therapy, patient preferences, and co-morbidities. All patients benefit from nonpharmacological lifestyle treatments such a weight-bearing exercise, adequate intake of calcium and vitamin D, fall prevention, avoidance of cigarette smoking and bone-toxic drugs, and moderation of alcohol intake. Patients at high risk for fracture should be considered for pharmacological therapy, which can reduce fracture risk by about 50%.

Experience of famine and bone health in post-menopausal women

BACKGROUND

Famines have occurred in all areas of the world in every period of history. Many studies have shown that poor growth and development and adverse environmental conditions in childhood are associated with osteoporosis in later life. However, little information is available on the relation between famine and bone health.

METHODS

This study examines the hypothesis that past experience of famine has an adverse impact on bone health, using data from Ms Os (Hong Kong), a large cohort study on osteoporosis in Asian women. There were 1,826 Hong Kong women aged 65 years or older recruited from the community. A standardized, structured interview and DXA were performed. Subjects who had experienced famine tended to have lower levels of education, social status and current daily calcium intake. They also have higher rates of cigarette consumption, depression and coronary heart disease.

RESULTS

After adjustment for confounders, we found that subjects who had experienced famine have a significantly higher rate of developing osteoporosis than those who had not.

CONCLUSIONS

We conclude that past exposure to famine, especially in childhood, is associated with osteoporosis.

Bone mineral density decrements and children diagnosed with cancer

This integrative literature review is focused on (1) the prevalence of bone mineral density (BMD) decrements in children treated for acute lymphoblastic leukemia (ALL), and when these decrements are observed; (2) the risk factors associated with the development of decreased BMD and resultant complications in children treated for ALL; (3) the role, if any, that corticosteroids play in decreasing BMD in children treated for ALL; (4) interventions that can potentially manage bone loss in people treated for ALL during childhood or adolescence. The results showed that people who have been diagnosed with ALL can have decrements in BMD. The etiology of BMD decrements can be attributed to multiple factors including genetic endowment, lifestyle behaviors, the leukemia disease process, and treatment exposures especially to corticosteroids and cranial radiotherapy. Male gender, age greater than 10 years, and physical inactivity are associated with BMD decrements in ALL survivors. The role of pediatric oncology nurses in the management of bone disease in children with cancer across the illness trajectory is discussed.

Oral bisphosphonates to treat disuse osteopenia in children with disabilities: a case series

Children with congenital conditions who are nonambulatory have been observed to have pathologic fractures due to disuse osteopenia. Data support the use of intravenous bisphosphonates to treat this in children with disabilities, but there are no data to guide the use of oral bisphosphonate medication. Ten nonambulatory children with disuse osteopenia secondary to either static brain injury or spina bifida were started on alendronate. Investigators completed a chart review of each subject. There were 17 fractures before starting alendronate and 1 fracture in the follow-up period. All children with nociceptive behavior or pain complaints (5/10) had their symptoms resolve after treatment. Despite the presence of gastrointestinal comorbidities (7/10 with a history of gastroesophageal reflux disease, 5/10 taking reflux medication, and 4/10 with PEG tubes), only 1 of the 10 children discontinued the medication secondary to gastrointestinal complaints. This case series offers evidence that disabled nonambulatory children tolerate alendronate, and it may decrease fractures in those at risk from severe disuse osteopenia.

Current advances in bone health of disabled children

PURPOSE OF REVIEW

Bone health is now recognized to contribute to overall lifetime management of children, adolescents, and adults with disabling conditions including physical and intellectual disability and with many chronic disease processes. Such disorders have multiple components, with aspects of care covering a wide number of specialist practices. This review will highlight advances in understanding the nature of bone mass accumulation through childhood and adolescence, the impingement of a spectrum of chronic and disabling diseases and their treatments on bone, and will address current approaches to interpretation of bone mass in the growing skeleton and interventional strategies for improving outcomes for this group.

RECENT FINDINGS

Increased skeletal fragility in the disabled child is well recognized. Insights into the contributions of skeletal size and bone strength in males and females have altered interpretation of data, allowing a new focus on determinants of future bone health, particularly with regard to the contributions of growth and puberty. Strategies to address bone health including public and medical education concerning consumption of calcium, appropriate selection of vitamin D preparations, pubertal contribution to phases of growth and possible specialist use of newer drugs, such as bisphosphonates where indicated, are changing the outlook for this large group.

SUMMARY

Implications of these changed understandings provide a new focus on maximizing bone mass accumulation by the end of adolescence within the constraints of what is possible to achieve for an individual and for provision of an holistic approach to bone health.