Preoperative considerations for the pediatric patient undergoing metabolic and bariatric surgery.

To ensure successful outcomes in pediatric patients with severe obesity who undergo metabolic and bariatric surgery (MBS), a number of pre-operative patient management options should be considered. This manuscript will review the indications and contraindications of MBS and special considerations for youth who might benefit from MBS. The treatment team conducts a thorough pre-operative evaluation, assessing risks and benefits of surgical intervention, and prepares patients and families to be successful with MBS by providing education about the surgical intervention and lifestyle changes that will be necessary. This article reviews the pre-operative considerations for adolescents with severe obesity who are being considered for MBS, based upon recent clinical practice guidelines.

Suboptimal bone microarchitecure in adolescent girls with obesity compared to normal-weight controls and girls with anorexia nervosa.

BACKGROUND: Despite their higher areal bone mineral density (aBMD), adolescents with obesity (OB) have an increase in fracture risk, particularly of the extremities, compared with normal-weight controls. Whereas bone parameters that increase fracture risk are well characterized in anorexia nervosa (AN), the other end of nutritional spectrum, these data are lacking in adolescents with obesity. OBJECTIVE: Our objective was to compare bone parameters in adolescent girls across the nutritional spectrum, to determine whether suboptimal bone adaptation to increased body weight may explain the increased fracture risk in OB. METHODS: We assessed bone endpoints in 153 adolescent girls 14-21 years old: 50 OB, 48 controls and 55 AN. We used (i) DXA to assess aBMD at the lumbar spine, proximal femur and whole body, and body composition, (ii) high resolution peripheral quantitative CT (HRpQCT) to assess bone geometry, microarchitecture and volumetric BMD (vBMD), and (iii) finite element analysis to assess failure load (a strength estimate) at the distal radius and tibia. All aBMD, microarchitecture and FEA analyses were controlled for age and race. RESULTS: Groups did not differ for age or height. Areal BMD Z-scores at all sites were highest in OB, intermediate in controls and lowest in AN (p < 0.0001). At the radius, cortical area and thickness were higher in OB compared to AN and control groups (p = 0.001) while trabecular area did not differ across groups. Compared to controls, OB had higher cortical porosity (p = 0.003), higher trabecular thickness (p = 0.024), and higher total, cortical and trabecular vBMD and rod BV/TV (p < 0.04). Plate BV/TV did not differ in OB vs. controls, but was higher than in AN (p = 0.001). At the tibia, total, cortical, and trabecular area and cortical thickness were higher in OB vs. controls and AN (p < 0.005). OB also had higher cortical porosity (p < 0.007) and lower trabecular thickness (p < 0.02) than the other two groups. Trabecular number, total and trabecular vBMD, and rod BV/TV were higher in OB vs. controls and AN (p < 0.02), while cortical vBMD and plate BV/TV did not differ in OB vs. the other two groups. Finally, failure load (a strength estimate) was higher in OB at the radius and tibia compared to controls and AN (p < 0.004 for all). However, after adjusting for body weight, failure load was lower in OB vs. controls at both sites (p < 0.05), and lower than in AN at the distal tibia. CONCLUSION: Not all bone parameters demonstrate appropriate adaptation to higher body weight. Cortical porosity and plate BV/TV at the radius and tibia, and cortical vBMD and trabecular thickness at the tibia are particularly at risk. These effects may contribute to the higher risk for fracture reported in OB vs. controls.

Sex differences in body composition and association with cardiometabolic risk.

BACKGROUND: Body composition differs between men and women, with women having proportionally more fat mass and men more muscle mass. Although men and women are both susceptible to obesity, health consequences differ between the sexes. The purpose of our study was to assess sex differences in body composition using anatomic and functional imaging techniques, and its relationship to cardiometabolic risk markers in subjects with overweight/obesity. METHODS: After written informed consent, we prospectively recruited 208 subjects with overweight/obesity who were otherwise healthy (94 men, 114 women, age 37 ± 10 years, BMI 35 ± 6 kg/m2). Subjects underwent dual-energy X-ray absorptiometry (DXA) and computed tomography (CT) for fat and muscle mass, proton MR spectroscopy (1H-MRS) for intrahepatic (IHL) and intramyocellular lipids (IMCL), an oral glucose tolerance test, serum insulin, lipids, and inflammatory markers. Men and women were compared by Wilcoxon signed rank test. Linear correlation and multivariate analyses between body composition and cardiometabolic risk markers were performed. RESULTS: Women and men were of similar mean age and BMI (p ≥ 0.2). Women had higher %fat mass, extremity fat, and lower lean mass compared to men (p ≤ 0.0005). However, men had higher visceral adipose tissue (VAT) and IMCL and higher age-and BMI-adjusted IHL (p < 0.05). At similar age and BMI, men had a more detrimental cardiometabolic risk profile compared to women (p < 0.01). However, VAT in women, and IMCL in men, were more strongly associated with cardiometabolic risk markers, while more lower extremity fat was associated with a more favorable cardiometabolic profile in women compared to men (p ≤ 0.03). CONCLUSIONS: Although the male pattern of fat distribution is associated with a more detrimental cardiometabolic risk profile compared to women of similar age and BMI, VAT is more strongly associated with cardiometabolic risk markers in women, while IMCL are more detrimental in men. Lower extremity fat is relatively protective, in women more than in men. This suggests that detailed anatomic and functional imaging, rather than BMI, provides a more complete understanding of metabolic risk associated with sex differences in fat distribution.