Bone mineral density, hip bone geometry, and calcaneus trabecular bone texture in obese and normal-weight children

Serum phospholipid fatty acids are associated with bone mass in healthy 4-years-old children

BACKGROUND

Fatty acids are involved in bone development but knowledge in children is limited. The aim of this study was to investigate bone mass and mineral density in healthy preschool children in relation to fatty acids.

MATERIAL AND METHODS

In 111 healthy 4-yrs-old children (20 % overweight) bone was analysed by dual X-ray absorptiometry and serum phospholipid fatty acid by gas chromatography. Fat intake was calculated from 7 days self-reported dietary records and food frequency questionnaire.

RESULTS

Total bone mass content (BMC) and mineral density (BMD) differed by sex in normal weight, but not in overweight children showing generally higher bone mass density than children with normal weight. Linoleic acid intake was strongly correlated to BMC and femoral BMD in normal weight children. Serum concentration of docosahexaenoic acid correlated positively to BMD in all children (p = 0.01), but linoleic and arachidonic acids, and monounsaturated fatty acids showed diverging associations with bone in normal weight and overweight children.

CONCLUSION

Serum phospholipid DHA was associated with bone density. Other fatty acids associations to bone sites differed in overweight children, analogue to the pattern in healthy 8-yrs-old.The finding need to be confirmed longitudinally and in a larger group of overweight individuals.

Effects of Different Levels of Weightlifting Training on Bone Mineral Density in a Group of Adolescents

The aim of the current study was to evaluate the effects of different levels of weightlifting training on bone mineral density (BMD) at different body sites (whole body (WB), lumbar spine (LS), femoral neck (FN), upper limbs (UL) and lower limbs (LL)) in a group of adolescents. Three groups of pubertal boys aged 13-15 years were recruited, including a control group (which included 13 untrained adolescents), a moderately trained group (which included 13 non-elite weightlifters, with four sessions of 2 hours per week) and a highly trained group (which included 13 elite weightlifters, with eight sessions of 2 hours per week). The three groups were paired for age and maturation index (using Tanner stages). Body composition, bone mineral content (BMC) and BMD were evaluated by dual-energy X ray absorptiometry (DXA). Physical performance variables (including weightlifting specific exercises, counter movement jump and squat jump) were measured using validated methods. Results showed that the values of BMD and physical performance variables were greater in the group of elite weightlifters compared to the group of non-elite weightlifters and the control group. In addition, the values of BMD and physical performance variables were higher in the group of the non-elite weightlifters compared to those of the control group. After adjusting for lean mass and squat jump, lumbar spine BMD, FN BMD, UL BMD and LL BMD remained significantly higher in the elite weightlifters' group compared to the two other groups. In conclusion, the current study suggests that elite adolescent weightlifters have greater bone health parameters compared to moderately-trained adolescent weightlifters and untrained adolescents.

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.

Bone mineral density and body composition in normal weight, overweight and obese children

BACKGROUND

There is a possibility that excess body fat affects bone mass gain and may compromise skeletal health in obese children. The purpose of the study was to identify the relationship between bone mineral density (BMD) and body composition in normal weight, overweight and obese children.

METHODS

This was a cross-sectional study of 6- to 11-year-old children who attended the hospital's outpatient clinic. They were apparently healthy and had no history of prematurity, low birth weight, or chronic diseases. Body mass index (BMI) was used to identify subjects as normal weight, overweight or obese. BMD and body composition were assessed by dual energy X-ray absorptiometry. The BMD values (total and lumbar spine) were compared between normal weight, overweight and obese children. Correlation coefficients were calculated, and multivariate models were performed.

RESULTS

Forty-nine children were included: 16 with normal weight, 15 that were overweight and 18 with obesity; the mean age was 8.4 ± 1.7 years. All the participants had a normal BMD (> - 2 SD). BMD was higher in obese children and had a positive correlation with total and trunk lean mass in the three study groups (p < 0.001). In obese children, an inverse correlation of lumbar spine BMD (Z score) with total and trunk fat mass (p < 0.05) was identified. In the multivariate models (with the whole group), the total lean mass was the only significant variable that explained BMD variability.

CONCLUSIONS

BMD in obese children was higher than that in normal weight children, which is explained by their greater lean mass and not by excess body fat. In obese children, a higher fat mass was related to a lower lumbar spine BMD. Lean mass had a direct correlation with BMD in the three study groups and was the most important predictor of BMD, reflecting the importance of strengthening the muscular system through performing physical activity and practicing a healthy lifestyle.

Does the Severity of Obesity Influence Bone Mineral Density Values in Premenopausal Women?

The aim of this study was to compare bone mineral content (BMC), bone mineral density (BMD), and geometric indices of hip bone strength among 3 groups of adult obese premenopausal women (severely obese, morbidly obese, and super morbidly obese). This study included 65 young adult premenopausal women whose body mass index (BMI) > 35 kg/m². They were divided into 3 groups using international cut-offs for BMI. Body composition and bone variables were measured by DXA. DXA measurements were completed for the whole body (WB), lumbar spine, total hip (TH), and femoral neck (FN). Geometric indices of FN strength (cross-sectional area, cross-sectional moment of inertia [CSMI], section modulus [Z], strength index [SI], and buckling ratio) were calculated by DXA. Results showed that age and height were not significantly different among the 3 groups. WB BMC values were higher in super morbidly obese women compared to severely and morbidly obese women. WB BMD, L1-L4 BMD, total hip BMD, FN BMD, cross-sectional area, CSMI, Z, and buckling ratio values were not significantly different among the 3 groups. SI values were lower in super morbidly obese compared to morbidly and severely obese women. In the whole population (n = 65), body weight, BMI, lean mass, fat mass, and trunk fat mass were positively correlated to WB BMC and negatively correlated to SI. Weight and lean mass were positively correlated to WB BMD and CSMI. Our findings suggest that the severity of obesity does not influence BMD values in premenopausal women.

Bone density, microarchitecture and strength estimates in white versus African American youth with obesity

BACKGROUND

African Americans (AA) have more favorable bone density and microarchitecture compared to Whites (W), which may explain their observed lower fracture rates. Obesity has deleterious effects on bone microarchitecture and strength estimates and is associated with an increase in fracture risk. Adolescence and young adulthood are periods of active bone accrual and also periods characterized by an increasing prevalence of obesity. The effect of obesity on the relationship between race and bone parameters remains unclear, particularly in youth.

OBJECTIVE

To assess differences in BMD, bone microarchitecture and strength estimates in AA and W adolescents and young adults with moderate to severe obesity. We hypothesized that racial differences in bone endpoints in lean youth would also be noted in youth with moderate to severe obesity.

METHODS

We evaluated 24 AA and 48 W adolescent and young adults with a mean age of 18.2 ± 2.4 years and a median body mass index (BMI) of 44.8 (40.5-49.4) kg/m² who underwent dual energy X-ray absorptiometry (DXA), high resolution peripheral quantitative computed tomography (HRpQCT), extended cortical analysis (ECA) and micro-finite element analysis (FEA) to obtain measures of volumetric bone mineral density (vBMD), bone geometry, microarchitecture, and strength estimates at the distal radius and tibia.

RESULTS

We found no differences between AA and W for total fat and lean mass, and areal BMD Z-scores (p > 0.05 for all). At the distal radius, no significant differences were detected in vBMD, bone geometry or microarchitecture (p > 0.05 for all); however, stiffness and failure load were higher in the AA group (p = 0.031 and 0.047 respectively). At the distal tibia, cortical vBMD was higher in AA vs. W (p = 0.012), while trabecular number was higher and trabecular separation lower in W vs. AA (p ≤ 0.028). Stiffness and failure load trended higher in AA vs. W (p = 0.052 and p = 0.048, respectively). Groups did not differ for any other bone parameter (p > 0.05).

CONCLUSION

Racial differences in bone endpoints appear to be less marked in those with moderate to severe obesity, suggesting that effects of obesity may blunt the effect of race on bone endpoints.

Determinants for low bone mineral density in pre-school children: a matched case-control study in Wuhan, China

Introduction Reduced bone mass will increase bone fragility and risk of fractures. Thus, it is better to note its determinants as early as possible. Objective This study aimed to find and determine the determinants for low bone mineral density (BMD) in pre-school children. Methods Between November 2014 and April 2015, a matched case-control study was performed to detect information on growth and development condition and consumption frequency of products of cases with low BMD and controls with normal BMD. Anthropometric data measurement and blood tests were conducted. Besides, the questionnaires concerning the mentioned information were completed to get relevant determinants. A paired t-test, the McNemar test and univariate and multiple conditional logistic regression models were used to explore the association between these factors and low BMD. Results In total, 88 (28 boys, 60 girls) incident cases (4.15 ± 0.78 years) of low BMD and 88 sex- and age-matched (±2 months) controls (4.16 ± 0.80 years) of normal BMD were enrolled. The results of multiple conditional logistic regression analysis indicated that if children had larger chest circumference (odds ratio [OR] = 0.763), longer duration of breastfeeding (OR = 0.899) and lower frequency of eating snacks (OR = 0.439), the risk of low BMD would decrease. Conclusions Our findings suggest that pre-school children with an association of larger chest circumference, longer duration of breastfeeding and lower frequency of eating snacks could have lower risk for low BMD. Intended measures to strengthen those protective factors could be effective in reducing the cases of low BMD.

Physical Performance Variables and Bone Parameters in a Group of Young Overweight and Obese Women

The aim of this study was to explore the relationships between physical performance variables and bone parameters such as bone mineral density (BMD), bone mineral content, hip geometry indices, and trabecular bone score in a group of young overweight and obese adult women. Sixty-eight overweight/obese (body mass index ≥25 kg/m²; 25.5-42.4 kg/m²) young women whose ages range from 18 to 35 yr participated in this study. Body composition and bone outcomes were measured by dual-energy X-ray absorptiometry. Maximum oxygen consumption (VO₂ max, in liter per minute) was determined indirectly using a progressive shuttle run test. One-repetition-maximum half-squat was directly measured. Vertical jump was measured and maximum power (P max) of the lower limbs was calculated. Lean mass was positively correlated to whole body (WB) BMD, total hip BMD, femoral neck (FN) BMD, femoral neck cross-sectional area (FN CSA) and femoral neck cross sectional moment of inertia (FN CSMI) (p < 0.05). VO₂ max (in liter per minute) and muscle power were positively correlated to WB BMD, total hip BMD, FN BMD, FN CSA, and FN CSMI (p < 0.05). One-repetition-maximum half-squat was positively correlated with lumbar spine trabecular bone score, WB BMD, FN BMD, FN CSA and FN CSMI (p < 0.05). This study suggests that lean mass, vertical jump, VO₂ max (liter per minute), muscle power and one-repetition-maximum half squat are positive determinants of BMD and hip geometry indices in young overweight and obese women.

Bone Geometric Properties of the Femoral Neck in Underweight Eumenorrheic Women

The aim of this study was to describe femoral neck (FN) geometry among eumenorrheic underweight women around the age of peak bone mass. Proximal femur geometry and body composition were assessed in 12 underweight women and in 24 healthy controls using dual-energy X-ray absorptiometry. The Hip Structural Analysis program was used to determine bone geometry at the FN. The cross-sectional area (CSA) and the cross-sectional moment of inertia (CSMI) were significantly lower in underweight women than in controls (p < 0.05). There was a trend toward lower sectional modulus (Z) and strength index in underweight women (p < 0.15). Body weight, body mass index, and lean mass (LM) were positively correlated with CSA, CSMI, Z, and neck-shaft angle (r = 0.428-0.611, p < 0.05). After controlling for body weight, body mass index, and LM, the differences in CSA, CSMI, Z, and neck-shaft angle were no more statistically significant between the 2 groups. The multivariate analysis retained LM as the main predictor of CSA, CSMI, and Z in the whole population. The present study suggests that thinness is associated with low resistance to axial forces (CSA) and bending load (Z and CSMI) in adult eumenorrheic women. LM seems to be a key determinant of FN geometry in underweight women.

Influence of adipose tissue mass on bone mass in an overweight or obese population: systematic review and meta-analysis

Context

The scientific literature shows conflicting evidence about the relationship between adiposity and bone mass in overweight and obese populations. The aim of this review was to quantify the correlation between adipose mass (absolute and relative) and bone mineral density (BMD) in overweight and obese populations. Three databases were searched electronically. In addition, reference lists of relevant articles were screened. A total of 16 studies, comprising 2587 participants and 75 correlation coefficients were selected for inclusion in the review. Data were extracted from each study using a standardized form. Multilevel modeling indicated opposing relationships between BMD and adiposity: absolute adiposity correlated positively, and relative adiposity negatively, with BMD. Sex and age were the primary moderators of these relationships. Strong evidence supported a negative relationship between relative adipose mass and BMD in men (R = -0.37; 95%CI, -0.57 to -0.12) and in those aged less than 25 years (R = -0.28; 95%CI, -0.45 to -0.08). To prevent bone loss in overweight and obese populations, nutrition- and exercise-based interventions that focus on a controlled reduction of adipose mass with concomitant preservation of lean mass are recommended. : PROSPERO no. CRD42015024313.

Body Mass Index Affects Proximal Femoral but Not Acetabular Morphology in Adolescents Without Hip Pathology

BACKGROUND

Increased mechanical load secondary to a large body mass index (BMI) may influence bone remodeling. The purpose of this study was to investigate whether BMI is associated with the morphology of the proximal part of the femur and the acetabulum in a cohort of adolescents without a history of hip disorders.

METHODS

We evaluated pelvic computed tomographic (CT) images in 128 adolescents with abdominal pain without a history of hip pathology. There were 44 male patients (34%) and the mean patient age (and standard deviation) was 15 ± 1.95 years. The alpha angle, head-neck offset, epiphysis tilt, epiphyseal angle, and epiphyseal extension were measured to assess femoral morphology. Measurements of acetabular morphology included lateral center-edge angle, acetabular Tönnis angle, and acetabular depth. BMI percentile, specific to age and sex according to Centers for Disease Control and Prevention growth charts, was recorded.

RESULTS

BMI percentile was associated with all measurements of femoral morphology. Each 1-unit increase in BMI percentile was associated with a mean 0.15° increase in alpha angle (p < 0.001) and with a mean 0.03-mm decrease in femoral head-neck offset (p < 0.001). On average, a 1-unit increase in BMI percentile was associated with a 0.0006-unit decrease in epiphyseal extension (p = 0.03), a 0.10° increase in epiphyseal angle (p < 0.001), and a 0.06° decrease in tilt angle (p = 0.02; more posteriorly tilted epiphysis). There was no detected effect of BMI percentile on acetabular morphology including lateral center-edge angle (p = 0.33), Tönnis angle (p = 0.35), and acetabular depth (p = 0.88).

CONCLUSIONS

Higher BMI percentile was associated with increased alpha angle, reduced head-neck offset and epiphyseal extension, and a more posteriorly tilted epiphysis with decreased tilt angle and increased epiphyseal angle. This morphology resembles a mild slipped capital femoral epiphysis deformity and may increase the shear stress across the growth plate, increasing the risk of slipped capital femoral epiphysis development in obese adolescents. BMI percentiles had no association with measurements of acetabular morphology. Further studies will help to clarify whether obese asymptomatic adolescents have higher prevalence of a subclinical slip deformity and whether this morphology increases the risk of slipped capital femoral epiphysis and femoroacetabular impingement development.

Physical Performance Variables and Bone Mineral Density in a Group of Young Overweight and Obese Men

The aim of this study was to explore the relationships between performances obtained in different physical tests and bone parameters (bone mineral density [BMD], bone mineral content, hip geometry indices, and trabecular bone score [TBS]) in a group of young Lebanese overweight and obese adult men. Fifty-two overweight and/or obese (body mass index > 25 kg/m²) young men whose ages range from 18 to 35 yr participated in this study. Weight and height were measured, and body mass index was calculated. Body composition, BMD, cross-sectional area and section modulus (Z) of the femoral neck (FN), and TBS were measured by dual-energy X-ray absorptiometry. Maximum oxygen consumption (VO₂ max, in liter per minute) was determined by direct measurement while exercising on a medical treadmill. One-repetition-maximum half-squat and maximum power (P max) of the lower limbs were measured using validated exercises. Lean mass was a positive determinant of whole-body bone mineral content (r = 0.71, p < 0.001), FN cross-sectional area (r = 0.51, p < 0.001), and FN Z (r = 0.58, p < 0.001). VO₂ max (in liter per minute) was a positive determinant of whole-body BMD (r = 0.47, p < 0.001), total hip BMD (r = 0.43, p < 0.01), and FN BMD (r = 0.42, p < 0.01). VO₂ max (in milliliter per minute per kilogram) was a positive determinant of TBS (r = 0.30, p < 0.05). One repetition maximum was a positive determinant of L1-L4 BMD (r = 0.33, p < 0.05). This study suggests that VO₂ max (in liter per minute) is a positive determinant of BMD, and VO₂ max (in milliliter per minute per kilogram) is a positive determinant of TBS in overweight and obese men.

Effects of interventions with a physical activity component on bone health in obese children and adolescents: a systematic review and meta-analysis

Given the rise in pediatric obesity, clarifications on the relationship between obesity and bone health and on the impact of structured intervention on this relationship are needed. This systematic review and meta-analysis investigated the effect of obesity on bone health and assessed the effect of structured intervention in children and adolescents with obesity. Medline complete, OVID, CINAHL, EMBASE and PubMed databases were searched for studies on obesity and bone health variables up to September 2016, then an update occurred in March 2016. Search items included obesity, childhood, dual energy X-ray absorptiometry and peripheral quantitative computed tomography. Twenty-three studies (14 cross-sectional and nine longitudinal) matched the inclusion criteria. Results from the meta-analysis (cross-sectional studies) confirmed that children and adolescents with obesity have higher bone content and density than their normal weight peers. Results from longitudinal studies remain inconclusive as only 50% of the included studies reported a positive effect of a structured intervention program on bone health. As such, the meta-analysis reported that structured intervention did not influence bone markers despite having beneficial effects on general health in youth with obesity.

Body composition and bone health in adolescents after Roux-en-Y gastric bypass for severe obesity

BACKGROUND

Laparoscopic Roux-en-Y gastric bypass (RYGB) causes changes in body composition and bone metabolism, yet little is known about effects in adolescents.

OBJECTIVES

The objective of this study was to report dual-energy X-ray absorptiometry measures and serum bone markers, hypothesizing that bone turnover increases after surgery.

METHODS

Inclusion criteria included the following: age 13-18 years and body mass index (BMI) >35 kg/m² . Seventy-two adolescents (22 boys; mean age 16.5 years; BMI 44.8 kg/m² ) undergoing RYGB underwent dual-energy X-ray absorptiometry and serum bone marker analyses preoperatively and annually for 2 years.

RESULTS

Mean BMI reduction at 2 years was 15.1 kg/m² . Body composition changes included a reduction in fat mass (51.8% to 39.6%, p < 0.001) and relative increase in lean mass (47.0% to 58.1%, p < 0.001). In contrast to previous studies in adults, adolescent boys lost a greater percentage of their body fat than girls (-17.3% vs. -9.5%, p < 0.001). Individual bone mineral density Z-scores (BMD-Z) at baseline were within or above the normal range. The mean (SD) BMD-Z was 2.02 (1.2) at baseline, decreasing to 0.52 (1.19) at 2 years. Higher concentrations of serum CTX (p < 0.001) and osteocalcin (p < 0.001) were observed in boys throughout the study period. Levels rose in the first year, before decreasing modestly in the second. Levels of serum markers of bone synthesis and resorption were higher in boys, whose skeletal maturity occurs later than girls'.

CONCLUSIONS

Differences in body fat and lean mass proportions were observed according to sex following RYGB. Bone turnover increased, and BMD decreased to levels approaching a norm for age. Long-term outcome will determine the clinical relevance.

Differences in bone mineral density between normal-weight children and children with overweight and obesity: a systematic review and meta-analysis

OBJECTIVE

This study examines the differences in bone mineral density between normal-weight children and children with overweight or obesity.

METHODS

A systematic review and meta-analysis of observational studies (published up to 22 June 2016) on the differences in bone mineral density between normal-weight children and overweight and obese children was performed. Results were pooled when possible and mean differences (MDs) were calculated between normal-weight and overweight and normal-weight and obese children for bone content and density measures at different body sites.

RESULTS

Twenty-seven studies, with a total of 5,958 children, were included. There was moderate and high quality of evidence that overweight (MD 213 g; 95% confidence interval [CI] 166, 261) and obese children (MD 329 g; 95%CI [229, 430]) have a significantly higher whole body bone mineral content than normal-weight children. Similar results were found for whole body bone mineral density. Sensitivity analysis showed that the association was stronger in girls.

CONCLUSIONS

Overweight and obese children have a significantly higher bone mineral density compared with normal-weight children. Because there was only one study included with a longitudinal design, the long-term impact of childhood overweight and obesity on bone health at adulthood is not clear.

Bone Variables in Active Overweight/Obese Men and Sedentary Overweight/Obese Men

The aim of this study was to compare bone variables in active overweight/obese men and sedentary overweight/obese men. Thirty-seven active overweight/obese men and 45 sedentary overweight/obese men participated in this study. Weight and height were measured, and body mass index was calculated. Body composition and bone variables (bone mineral content [BMC], bone mineral density [BMD], geometric indices of hip bone strength, and trabecular bone score) were measured by DXA. Physical activity level, daily calcium intake, daily protein intake, and sleep duration were measured by validated questionnaires. Maximum oxygen consumption (VO₂ max) was determined by direct measurement while exercising on a medical treadmill. One-repetition-maximum half-squat of the lower limbs was measured using a validated protocol. Body weight and body mass index were higher in sedentary overweight/obese men than in active overweight/obese men. In the whole population (n = 82), VO₂ max (in liter per minute), lean mass, and one-repetition-maximum half-squat were positively correlated to BMC, BMD, and geometric indices of hip bone strength (cross-sectional area and section modulus [Z] of the femoral neck [FN]). After adjusting for body weight using a 1-way analysis of covariance, active overweight/obese men displayed higher whole-body BMC, lumbar spine BMD, total hip BMD, FN BMD, FN cross-sectional area, and FN Z values than sedentary overweight/obese men. In conclusion, the current study suggests that physical activity level positively affects bone variables in overweight/obese men. Optimizing lean mass and muscular strength of the lower limbs can help to prevent osteoporosis in overweight and obese men.