Differences in childhood adiposity influence upper limb fracture site

Forearm Fractures in Overweight-Obese Children and Adolescents: A Matter of Bone Density, Bone Geometry or Body Composition?

Forearm fractures in children and adolescents are associated with increased body mass index (BMI). This bone site is non-weight-bearing and therefore is appropriate to explore the effect of BMI on bone mineral density (BMD) and bone geometry, avoiding the confounding effect of increased weight-associated mechanical loading. The aim of this review was to summarize available evidence on bone indices and body composition assessed by peripheral quantitative computed tomography (pQCT) or dual X-ray absorptiometry (DXA) at the forearm level in overweight (Ow) or obese (Ob) subjects. We conducted a review of the literature according to the PICOS model. A total of 46 studies were identified following the literature search. A final number of 12 studies were included in this review. pQCT studies evidenced that Ow and Ob children typically have normal or increased volumetric BMD (vBMD), total bone area and cortical area, with normal or reduced cortical thickness at the forearm. Outcomes from DXA evaluations are less conclusive. In almost all the studies fat mass and lean mass area at the forearm are increased. A higher fat-to-lean mass ratio has been observed in few studies. Bone strength was reported as normal or increased compared to normal weight peers. In Ow or Ob children-adolescents, vBMD, bone size and bone strength are not reduced compared to normal weight peers. The local higher fat-to-lean mass ratio may give a mismatch between bone strength and the load experienced by the distal forearm during a fall, resulting in increased risk of forearm fractures.

The incidence of distal radius fractures in a Swedish pediatric population - an observational cohort study of 90 970 individual fractures

Background

40–50 % of all boys and 30–40 % of girls suffer from at least one fracture during childhood. A quarter of these fractures affects the wrist, making it the worst affected part of the body. Children often sustain the injury during play or sport activities. There has been a lifestyle change among European children during the last decades, and there is reason to believe that fracture incidence is changing.

Methods

For the purpose of this observational cohort study registry data was retrieved from the Swedish National Patient Register for all pediatric patients registered with a distal radius fracture during the period 2005–2013. Incidence rates were calculated for each year using data from Statistic Sweden on population size by age and gender.

Results

90 970 distal radius fractures were identified. The mean age at the time of fracture was 10 years. In ages 10–17 the proportion of male patients was significantly larger. Seasonal variations were detected with peak incidences in May and September. A decreasing total fracture incidence was observed during the study period.

Conclusions

The incidence of distal radius fractures in a population 0–17 years in Sweden was higher among male than in female patients. The incidence was lower in 2008–2013 as compared to 2005. Further studies are necessary to reveal if the incidence will continue to decrease.

Sex-specific differences in somatic investment and strategies of physical activity among Portuguese schoolchildren

OBJECTIVES

Physical activity (PA) is required for healthy growth, development, and maturation and plays an important role in the prevention of overweight and obesity in childhood and adolescence. Sex-differences in PA levels are well documented, with boys spending more time in PA, especially in moderate-to-vigorous activities. Following the Life History Theory, our aim is to study if PA affects the fat tissues increases during childhood and juvenile phases in both sexes.

METHODS

Time spent in sedentary, light, and moderate-to-vigorous PA levels were measured in a sample of 415 Portuguese children and juveniles (207 females/208 males; aged 6-11 years), using an accelerometer for 7 days. Skinfolds related with body fat were objectively collected and socioeconomic status factors were reported using a parental questionnaire.

RESULTS

The outcomes show that girls' and boys' fat variables increased during the end of the childhood and the juvenile phase. However, these variables were differently affected by PA. Girls increased fat variables with the sedentary activity while boys decreased fat variables with moderate-to-vigorous PA. Alike, active boys but not girls reduced the fat increase tendency with age.

CONCLUSIONS

Although both sexes displayed a general fat increment with age, moderate-to-vigorous PA dampens the increase only in boys. In fact, active girls increased body fat in the same manner as non-active girls. From an evolutionary perspective, it could explain sex-specific somatic strategies related to future reproduction or, with future mating and intrasexual competition.

Arachidonic acid status negatively associates with forearm bone outcomes and glucose homeostasis in children with an overweight condition or obesity

Long-chain polyunsaturated fatty acids are implicated in musculoskeletal health in adults. This study examined whether fatty acid status relates to bone health outcomes in children with overweight condition or obesity (body mass index z score, 3.1 ± 0.1; age, 9.0 ± 0.2 years; n = 108). Nondominant forearm bone density (distal one-third), geometry (4% site), and soft tissue composition (66%) were assessed using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography. Red blood cell (RBC) fatty acid profile and indices of glucose homeostasis were measured. Differences in outcomes among RBC arachidonic acid (AA, C20:4n-6) tertiles were tested using mixed-model ANOVA. Ultra-, mid-, and total-distal forearm bone mineral content, adjusted for sex, age, percentage body fat, race, and forearm length, were 10% to 13% greater in children in the first AA tertile relative to the third. Children in the second tertile had the highest bone cross-sectional area and estimated strength at the 66% radius. Muscle cross-sectional area was 15% lower in the third tertile compared with the first, along with higher fasting insulin concentrations (27%) and homeostasis model of assessment estimate of insulin resistance (31%). Higher RBC AA status aligns with deficits in forearm bone mass, geometry, and muscle mass in children with excess adiposity and early signs of insulin resistance. Novelty Higher arachidonic acid status is associated with lower forearm bone mass in children with overweight condition or obesity. Children with higher arachidonic acid status had increased fasting insulin concentrations and indices of insulin resistance.

The role of PPARγ in childhood obesity-induced fractures

Globally, obesity is on the rise with ~ 30% of the world’s population now obese, and childhood obesity is following similar trends. Childhood obesity has been associated with numerous chronic conditions, including musculoskeletal disorders. This review highlights the effects of childhood adiposity on bone density by way of analyzing clinical studies and further describing two severe skeletal conditions, slipped capital femoral epiphysis and Blount’s disease. The latter half of this review discusses bone remodeling and cell types that mediate bone growth and strength, including key growth factors and transcription factors that help orchestrate this complex pathology. In particular, the transcriptional factor peroxisome proliferator-activated receptor gamma (PPARγ) is examined as it is a master regulator of adipocyte differentiation in mesenchymal stem cells (MSCs) that can also influence osteoblast populations. Obese individuals are known to have higher levels of PPARγ expression which contributes to their increased adipocyte numbers and decreased bone density. Modulating PPAR*gamma* signaling can have significant effects on adipogenesis, thereby directing MSCs down the osteoblastogenesis pathway and in turn increasing bone mineral density. Lastly, we explore the potential of PPARγ as a druggable target to decrease adiposity, increase bone density, and be a treatment for children with obesity-induced bone fractures.

An epidemiological evaluation of fractures and its determinants among Lebanese schoolchildren: a cross-sectional study

The purpose of this study is to establish the prevalence and determinants of fractures among 974 Lebanese schoolchildren aged 8-18. Fractures might be less common in the Lebanese pediatric population compared to western populations. Male gender and high SES are independent risk factors for fractures, while 25(OH)D and BMI have no impact.

PURPOSE

To establish the prevalence of fractures among Lebanese schoolchildren and its relationship with age, gender, BMI, 25 hydroxyvitamin D (25(OH)D) levels, and socioeconomic status (SES).

METHODS

In this cross-sectional study, 974 Lebanese schoolchildren aged 8-18 years old, mean age 13.37 ± 2.92 (508 boys and 466 girls), were recruited from 10 schools with different SES. For each participant, a questionnaire was used to collect data regarding history of fractures. Serum 25(OH)D was also measured.

RESULTS

The prevalence of Lebanese children sustaining ≥ 1 fracture was 16.9% and was higher in boys compared to girls (22.2% vs 11.1%, p < 0.0001). A 71.3% of fractures were localized in the upper limbs and 20% of participants had at least one displaced fracture. Children who sustained a fracture had a non-significant higher BMI compared to those without (p = 0.096). The percentage of children with fractures was higher in children from high SES compared to those from middle and low SES (respectively 23.3% vs. 16.3% and 13.8%, p < 0.0001). Fractures occurred at a younger age in girls compared to boys, but this difference was non-significant (p = 0.13). 25(OH)D levels were significantly higher in children with fractures compared to those without (p = 0.017). Finally, female gender was protective against upper limb fractures (p = 0.009). In a logistic regression analysis, male gender and high SES were independently associated with fractures, while BMI and 25(OH)D were not.

CONCLUSION

Our study demonstrates that the prevalence of fractures in the Lebanese pediatric population might be lower than western populations. It also confirms that male gender and high SES are independent risk factors for fractures, while 25(OH)D and BMI were not independently associated with fracture risk.

Gait Pattern, Impact to the Skeleton and Postural Balance in Overweight and Obese Children: A Review

The article reviews the biomechanical factors that may cause overweight/obese children to reduce their level of physical activity, while increasing their risk of overuse injuries and exercise-related pain. Recommendations would be to screen those children for any gait or postural impairments before they join any exercise program, and to provide them with specific gait treatments and/or physical exercise programs, in order to decrease their risk for future musculoskeletal injuries and pain.

Evaluating Weight Status and Sex as Moderators of the Association of Serum Leptin with Bone Mineral Density in Children and Adolescents

BACKGROUND/AIMS

Animal studies suggest that leptin may adversely affect bone mineral density (BMD). Clinical studies have yielded conflicting results. We therefore investigated associations between leptin and bone parameters in children.

METHODS

830 healthy children (age = 11.4 ± 3.1 years; 75% female; BMI standard deviation score [BMIz] = 1.5 ± 1.1) had fasting serum leptin measured with ELISA and body composition by dual-energy X-ray absorptiometry. The main effects for leptin and BMIz plus leptin's interactions with sex and BMIz were examined using hierarchical linear regressions for appendicular, pelvis, and lumbar spine BMD as well as bone mineral content (BMC), and bone area (BA).

RESULTS

Accounting for demographic, pubertal development, and anthropometric variables, leptin was negatively and independently associated with lumbar spine BMC and BA, pelvis BA, and leg BA (p < 0.05 for all). Sex, but not BMIz, moderated the associations of leptin with bone parameters. In boys, leptin was negatively correlated with leg and arm BMD, BMC at all bone sites, and BA at the subtotal and lumbar spine (p < 0.01 for all). In girls, leptin was positively correlated with leg and arm BMD (p < 0.05 for both).

CONCLUSION

Independent of body size, leptin is negatively associated with bone measures; however, these associations are moderated by sex: boys, but not girls, have a negative independent association between leptin and BMD.
.

Ethnic and geographic variations in the epidemiology of childhood fractures in the United Kingdom

BACKGROUND

Fractures are common in childhood, and there is considerable variation in the reported incidence across European countries, but few data relating to ethnic and geographic differences within a single country. We therefore aimed to determine the incidence of childhood fractures in the United Kingdom (UK), and to describe age-, ethnicity- and region- specific variations.

METHODS

The Clinical Practice Research Datalink (CPRD) contains anonymised electronic health records for approximately 7% of the UK population. The occurrence of a fracture between 1988 and 2012 was determined from the CPRD for all individuals <18years of age, and used to calculate fracture incidence rates for age, sex and ethnicity. Regional fracture incidence rates were also calculated based on general practitioner location within 14 Strategic Health Authorities (SHA) within the UK.

RESULTS

The overall fracture incidence rate was 137 per 10,000 person-years (py). This was higher in boys (169 per 10,000 py) than girls (103 per 10,000 py) and white children (150 per 10,000 py) compared to those of black (64 per 10,000 py) and South Asian (81 per 10,000 py) ethnicity. Marked geographic variation in incidence was observed. The highest fracture rates were observed in Wales, where boys and girls had 1.82 and 1.97 times greater incidence, respectively, than those residing in Greater London.

CONCLUSION

In the period 1988-2012, there was marked geographic and ethnic variation in childhood fracture incidence across the UK. These findings also implicate lifestyle and socio-economic differences associated with location and ethnicity, and are relevant to policy makers in the UK and internationally.

Nutrient and food intakes in early life and risk of childhood fractures: a systematic review and meta-analysis

BACKGROUND

The identification of detrimental dietary patterns early in life may contribute to reducing the high incidence of fracture among healthy children. However, information based on a systematic review of the effect of various dietary foods and nutrients on fracture risk is lacking.

OBJECTIVE

We conducted a systematic review and meta-analysis of observational studies that examined the association between dietary intake or serum nutritional concentrations and childhood fractures.

DESIGN

Studies published up until June 2015 were identified on the basis of a literature search in Medline, Web of Science, and Scopus databases and by hand searching references by first author based on predefined inclusion criteria. A meta-analysis was carried out for case-control studies that examined differences in mean calcium intake in the case compared with the control group. Random-effects analysis was performed on the basis of the effect estimates derived as the differences in mean calcium intakes between cases and controls.

RESULTS

From a total of 1960 articles, we identified 18 observational studies, which were primarily case-control in design. Randomized controlled trials were absent, potentially because of unethical aspects related to the enrollment of children randomly assigned to certain dietary exposures and later fracture rates. Overall, fracture risk seemed to be associated with milk avoidance, high energy intake, high cheese intake, high intake of sugar-sweetened beverages, and no breastfeeding. The pooled effect size of the 9 case-control studies that examined mean calcium intake, which had appropriate data for the meta-analysis, showed no association (P = 0.99) with fair heterogeneity (I(2) = 69.3%, P = 0.001) with the use of the random-effects model.

CONCLUSIONS

On the basis of a systematic review of studies that were judged to be of high or medium quality, there is an indication that some nutritional factors seem to be associated with an increased fracture risk among children. The results may be inflated by selection bias, bias in diet reporting, or residual confounding. More high-quality longitudinal observational or intervention studies are needed on the subject.