Insulin and bone health in young adults: The mediator role of lean mass

Association between lean mass and adolescent idiopathic scoliosis: a meta-analysis

OBJECTIVE

The objective of this meta-analysis was to evaluate the association between lean mass and adolescent idiopathic scoliosis (AIS).

METHODS

English databases CENTRAL (The Cochrane Library and the Cochrane Back Review Group Trials Register), MEDLINE, EMBASE, PubMed, Web of Science and Chinese databases CBM, CNKI, VIP, WANGFANG DATA were searched for the relevant case control studies and cross-sectional studies. Two authors selected studies and extracted data independently. Data analysis was performed by Stata15.0.

RESULTS

Eight studies were included, with a total of 1771 cases of AIS and 6340 controls. AIS group had a lower lean mass compared to control group [MD =  - 1.95, 95% CI (- 2.96, - 0.93)]. In the subgroup analysis, female AIS patients had a lower lean mass than the control group [MD =  - 1.76, 95% CI (- 2.63, - 0.88)]. The mean difference of lean mass between AIS patients and control group in studies with adults [MD =  - 3.96, 95% CI (- 7.26, - 0.67)] is much greater than studies without adults [MD =  - 1.04, 95% CI (- 1.59, - 0.49)]. There was not statistically significant in European studies [MD =  - 2.10, 95% CI (- 4.35, 0.14)], but in Asian studies lean mass in AIS patients was lower than the control group [MD =  - 2.26, 95% CI (- 3.98, - 0.54)]. Study type, gender, age, and geography condition were thought to have no effect on the primary outcome of lean mass by subgroup analysis.

CONCLUSION

In the meta-analysis, AIS group had a lower lean mass compared to control group, which indicated that lean mass may be involved in the pathogenesis of AIS. But limited by the number of studies we included; the above conclusions need to be validated by more high-quality studies.

Body composition phenotypes and bone health in young adults: A cluster analysis

BACKGROUND AND AIMS

Lean mass is considered the best predictor of bone mass, as it is an excellent marker of bone mechanical stimulation, and changes in lean mass are highly correlated with bone outcomes in young adults. The aim of this study was to use cluster analysis to examine phenotype categories of body composition assessed by lean and fat mass in young adults and to assess how these body composition categories are associated with bone health outcomes.

METHODS

Cluster cross-sectional analyses of data from 719 young adults (526 women) aged 18-30 years from Cuenca and Toledo, Spain, were conducted. Lean mass index (lean mass (kg)/height (m)2), fat mass index (fat mass (kg)/height (m)2), bone mineral content (BMC) and areal bone mineral density (aBMD) were assessed by dual-energy X-ray absorptiometry.

RESULTS

A cluster analysis of lean mass and fat mass index z scores resulted in a classification of a five-category cluster solution that could be interpreted according to the body composition phenotypes of individuals as follows: high adiposity-high lean mass (n = 98), average adiposity-high lean mass (n = 113), high adiposity-average lean mass (n = 213), low adiposity-average lean mass (n = 142), and average adiposity-low lean mass (n = 153). ANCOVA models showed that individuals in clusters with a higher lean mass had significantly better bone health (z score: 0.764, se: 0.090) than their peers in other cluster categories (z score: -0.529, se: 0.074) after controlling for sex, age, and cardiorespiratory fitness (p < 0.05). Additionally, subjects belonging to the categories with a similar average lean mass index but with high or low-adiposity levels (z score: 0.289, se: 0.111; z score: 0.086, se: 0.076) showed better bone outcomes when the fat mass index was higher (p < 0.05).

CONCLUSIONS

This study confirms the validity of a body composition model using a cluster analysis to classify young adults according to their lean mass and fat mass indices. In addition, this model reinforces the main role of lean mass on bone health in this population and that in phenotypes with high-average lean mass, factors associated with fat mass may also have a positive effect on bone status.

Pubertal increment in insulin resistance is negatively related to lumbar bone mineral density in 18-year-old males

Transient insulin resistance seen during puberty is expected to favour body growth, but our results show that increment in insulin resistance even in physiological ranges during puberty might compromise lumbar spine bone mineral density accrual independently of body composition parameters, and therefore adult bone quality might be challenged.

INTRODUCTION

Insulin resistance (IR) might have a compromising effect on growing bone, and therefore adult bone quality might be challenged. The aim of the present study was to identify whether increases in IR during puberty contribute to bone mineral characteristics in males independently of body composition parameters.

METHODS

This is a retrospective cohort-based longitudinal observational study. Data from 85 subjects were included. Boys were studied annually during their pubertal years (12 years at baseline) and at follow-up at the age of 18 years. Anthropometry, bone age, fasting blood samples, body composition, total body, and lumbar spine bone mineral characteristics were measured. Insulin resistance was determined by homeostatic model assessment of IR (HOMA-IR). Multiple regression analysis was performed to determine the effect of changes in HOMA-IR during pubertal years as a longitudinal predictor to fixed bone mineral outcome variables at the age of 18 years. All models were adjusted to potential clinically justified confounding variables.

RESULTS

After adjustment to baseline bone indices and body composition-related predictors, the pubertal increment in the HOMA-IR was a negative independent predictor of lumbar spine bone mineral areal density (β =  - 0.202, p = 0.005) and lumbar spine bone mineral apparent density (β =  - 0.235, p = 0.005) in 18-year-old males.

CONCLUSIONS

Pubertal increment in IR has a potential diminishing effect on lumbar spine bone mineral density accrual independently of body composition parameters. Further studies are needed to clarify whether monitoring HOMA-IR during puberty may identify subjects at increased risk of low peak bone mass and possible osteoporosis in the future.

A narrative review of diabetic bone disease: Characteristics, pathogenesis, and treatment

Recently, the increasing prevalence of diabetes mellitus has made it a major chronic illness which poses a substantial threat to human health. The prevalence of osteoporosis among patients with diabetes mellitus has grown considerably. Diabetic bone disease is a secondary osteoporosis induced by diabetes mellitus. Patients with diabetic bone disease exhibit variable degrees of bone loss, low bone mineral density, bone microarchitecture degradation, and increased bone fragility with continued diabetes mellitus, increasing their risk of fracture and impairing their ability to heal after fractures. At present, there is extensive research interest in diabetic bone disease and many significant outcomes have been reported. However, there are no comprehensive review is reported. This review elaborates on diabetic bone disease in the aspects of characteristics, pathogenesis, and treatment.

The Mediating Role of Endocrine Factors in the Positive Relationship Between Fat Mass and Bone Mineral Content in Children Aged 9-11 Years: The Physical Activity and Nutrition in Children Study

INTRODUCTION

We aimed to investigate whether the relationship between fat mass and bone mineral content (BMC) is mediated by insulin, leptin, adiponectin, dehydroepiandrosterone sulphate, testosterone and estradiol in children aged 9-11 years.

MATERIALS AND METHODS

We utilised cross-sectional data from the Physical Activity and Nutrition in Children study (n = 230 to 396; 112 to 203 girls). Fat mass and BMC were assessed with dual-energy X-ray absorptiometry. Endocrine factors were assessed from fasted blood samples. We applied the novel 4-way decomposition method to analyse associations between fat mass, endocrine factors, and BMC.

RESULTS

Fat mass was positively associated with BMC in girls (ß = 0.007 to 0.015, 95% confidence interval (CI) 0.005 to 0.020) and boys (ß = 0.009 to 0.015, 95% CI 0.005 to 0.019). The relationship between fat mass and BMC was mediated by free leptin index in girls (ß = -0.025, 95% CI -0.039 to -0.010) and boys (ß = -0.014, 95% CI -0.027 to -0.001). The relationship between fat mass and BMC was partially explained by mediated interaction between fat mass and free leptin index in boys (ß = -0.009, 95% CI -0.013 to -0.004) and by interaction between fat mass and adiponectin in girls (ß = -0.003, 95% CI -0.006 to -0.000).

CONCLUSION

At greater levels of adiponectin and free leptin index, the fat mass and BMC relationship becomes less positive in girls and boys respectively. The positive association between fat mass with BMC was largely not explained by the endocrine factors we assessed.

CLINICAL TRIAL REGISTRATION

[https://clinicaltrials.gov/ct2/show/NCT01803776], identifier NCT01803776.

The Role of Chronic Physical Activity in Alleviating the Detrimental Relationship of Childhood Obesity on Brain and Cognition

Childhood obesity and its negative relation with children’s brain health has become a growing health concern. Over the last decade, literature has indicated that physical activity attenuates cognitive impairment associated with obesity and excess adiposity in children. However, there is no comprehensive review that considers the extent to which these factors affect different domains of cognition. This narrative review comprehensively summarizes behavioral, neuroimaging, and neuroelectric findings associated with chronic physical activity and fitness on brain and cognition in childhood obesity. Based on the literature reviewed, increased adiposity has a demonstrated relationship with neurocognitive health via mechanisms triggered by central inflammation and insulin resistance, with the most pronounced decrements observed for cognitive domains that are prefrontal- and hippocampal-dependent. Fortunately, physical activity, especially interventions enhancing aerobic fitness and motor coordination, have demonstrated efficacy for attenuating the negative effects of obesity across different subdomains of structural and functional brain imaging, cognition, and multiple academic outcomes in children with overweight or obesity. Such mitigating effects may be accounted for by attenuated central inflammation, improved insulin sensitivity, and increased expression of neurotrophic factors. Lastly, individual differences appear to play a role in this relationship, as the manipulation of physical activity characteristics, the employment of a wide array of cognitive and academic measures, the inclusion of different adiposity measures that are sensitive to neurocognitive function, and the utilization of an inter-disciplinary approach have been found to influence the relationship between physical activity and excess adiposity on brain and cognition.

Insulin resistance and bone health in adolescents

Insulin resistance may be linked to bone health in young people. This study is the first on adolescents that jointly examined the association of bone health with insulin resistance and body composition. Our results revealed significant negative association between bone parameters and insulin resistance, even after adjustment for confounding factors.

PURPOSE

Previous studies are suggestive of the protective role of insulin on bone in adults. Whether this association exists in younger individuals is not clear, yet. This investigation aimed to evaluate the association between insulin resistance, bone parameters, and body composition amongst Iranian adolescents᾽ population.

METHODS

A cross-sectional study was conducted on 423 participants (224 girls and 199 boys) aged 9-19 years old. Insulin resistance was assessed, using a homeostatic model assessment of insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI). Bone mineral density (BMD), bone mineral content (BMC), total body fat mass (TBFM), and total body lean mass (TBLM) were measured, using dual energy X-ray absorptiometry (DXA), and bone mineral apparent density (BMAD) was calculated.

RESULTS

In multiple regression analyses adjusted for potential confounders, the HOMA-IR showed statistically significant negative association with most of the bone parameters (β = - 1.1 to - 0.002, P = 0.004 to 0.036). On the subject of QUICKI index, this relationship was detected only for lumbar spine (LS) parameters (β = 0.062 to 37.21, P = 0.0001 to 0.026) and femoral neck bone mineral content (FNBMC) (β = 1.297, P = 0.013).

CONCLUSION

Our results suggest that insulin resistance may be inversely and independently associated with the bone indices in younger individuals. Whether high insulin levels have detrimental effects on growing bone is still unclear and has to be answered.

Ameliorating effect of leukotriene receptor antagonist in multi-organ toxicity induced in rat offspring, a possible role for epidermal growth factor

Purpose: Nowadays, there is a dramatic increase in the interest of potential impact of consumer-relevant engineered nanoparticles on pregnancy.Materials and methods: This study investigated the possible protective effect of montelukast in neonatal organ toxicity induced by maternal exposure to silver nanoparticles (AgNPs) in rats.Results: It was noticed that montelukast reduced serum urea, creatinine, renal caspase-3 immunoreactivity and IL-1β and increased total antioxidant capacity, as compared to AgNPs. In kidney and bone tissue, montelukast reduced oxidative stress parameters and TNF-α level that was increased with AgNPs. Surprisingly, montelukast administration increased epidermal growth factor (EGF) in bone and reduced it in kidney. Furthermore, as compared to AgNPs, montelukast improved histopathological picture of kidney and bone.Conclusions: In conclusion, montelukast antagonized the biochemical and histopathological changes occurred in kidneys and bones of rat offspring by maternal exposure to AgNPs, mostly by anti-oxidant, anti-apoptotic and anti-inflammatory actions with a possible role for EGF.

Lean mass index is positively associated with white matter volumes in several brain regions in children with overweight/obesity

BACKGROUND

The relationship of obesity with grey and white matter volumes has been examined in several studies, and the results are decidedly mixed.

OBJECTIVE

To investigate the associations of body mass index (BMI), fat mass index (FMI) and lean mass index (LMI) with total and regional grey and white matter volumes.

METHODS

This is a cross-sectional study involving 100 children (60% boys) with overweight/obesity. T1-weighted images were acquired using magnetic resonance imaging. Dual energy X-ray absorptiometry was used to measure body composition. Separate hierarchical regression analyses were performed between predictor variables (BMI, FMI and LMI) and the total brain volumes including sex, years from peak height velocity and parental education as covariates. In addition, FMI was added as a covariate when LMI was the predictor and vice versa. Statistical analyses of imaging data were performed using three whole-brain voxel-wise multiple regression models and adjusted by the same covariates.

RESULTS

LMI was positively associated with white matter in numerous regions and to a lower extent, with grey matter regions. Further, the relationship between LMI, and grey and white matter regions was independent of FMI levels.

CONCLUSIONS

LMI seems to be a positive predictor of regional white matter volumes in children with overweight/obesity.

[Diabetes mellitus and risk of hip fracture. A systematic review]

BACKGROUND AND OBJECTIVES

It has been reported that the risk of fracture is increased in patients with diabetes mellitus (DM). The aim of this study was to investigate the possible relationship between DM and hip fracture, as well as any associated risk factors, by means of a systemic review of the literature.

METHODS

PubMed and SCOPUS databases were used to search for relevant studies published from January 2001 to August 2018. Retrospective and prospective cohort studies were selected in which the estimated risk of hip fracture was demonstrated by comparing groups of diabetic patients with non-diabetics. A search was also made for risk factors independent from the association between DM and hip fracture.

RESULTS

A total of 27 articles that fulfilled the inclusion criteria were included. A clear association was observed in diabetic patients (women and men) compared to non-diabetics patients. Among the risk factors, the most important ones were the fact that diabetes was type 1, probably associated with greater risk to a longer duration of DM, and being a female.

CONCLUSIONS

There is an increased risk of hip fracture in patients diagnosed with DM. This association is more significant in diabetes type 1 and women.

Bone mass development is sensitive to insulin resistance in adolescent boys

PURPOSE

Insulin resistance may exert a negative influence on bone mass in childhood and adolescence. The objective was to assess the association between insulin resistance and total body less head (TBLH) bone mineral content (BMC) and to investigate whether body composition, physical activity or osteocalcin levels may influence this association.

METHODS

A longitudinal study with follow-up over more than 6 years was performed and included 562 apparently healthy participants with a mean age of 9.6 years at baseline. Participants underwent DXA scanning at baseline. At the two follow-ups, participants had performed another DXA scanning, had blood samples taken for fasting insulin, glucose and osteocalcin and had physical activity measured with an accelerometer. HOMA-IR was calculated as an index of insulin resistance.

RESULTS

HOMA-IR was negatively associated with TBLH BMC in boys at follow-ups (β = -31.4, p < 0.001) after adjustment for maturity, height, bone area, and baseline level of TBLH BMC. The negative association remained almost unchanged after further adjustments for body composition and physical activity. No association between HOMA-IR and TBLH BMC was found in girls.

CONCLUSION

Insulin resistance may be detrimental for bone development through puberty in boys independent of body composition and the level of physical activity.