Total body protein in healthy adolescent girls: validation of estimates derived from simpler measures with neutron activation analysis

Long-term Outcomes of Adolescent Anorexia Nervosa on Bone

PURPOSE

Anorexia nervosa (AN) is a chronic and life-threatening eating disorder that can have a considerable negative impact on the growing skeleton. We hypothesized that the long-term impact on bone health may persist even after normalization of body weight.

METHODS

41 females (mean age 21.2 ± 2.9 years) with a history of adolescent-onset AN attended a follow-up bone health assessment at 5 years (T5, n = 28) or 10 years (T10, n = 13) after their first AN-related hospital admission. Assessment included dual-energy x-ray absorptiometry measurements of the total body, lumbar spine, and proximal femur, peripheral quantitative computed tomography at the radius and tibia, anthropometric measurements, serum biochemistry, fracture history, and a patient questionnaire.

RESULTS

A recovery in body weight and BMI was seen for both the T5 and T10 cohorts (BMI at intake 16.6, BMI at T5-T10 21.2-21.3). Dual-energy x-ray absorptiometry body composition indicated a recovery of fat mass and lean tissue mass. Total BMD was unaffected, but reductions were seen at the femoral neck and arms. Peripheral quantitative computed tomography showed reduced trabecular and cortical bone in the radius, and cortical thinning in the tibia. AN patients showed a statistically significant reduction in measures of radiographic bone health at follow up, although not to a degree that necessitated clinical intervention. Serum insulin-like growth factor 1 was also positively correlated with total BMD and BMC measures. While fracture risk was not increased, a subset of participants (8%) showed multiple (>4) fractures.

CONCLUSION

A longitudinal study of adolescent AN showed persisting negative effects on bone health.

Incomplete total body protein recovery in adolescent patients with anorexia nervosa

Background

Bone health and growth during adolescence require adequate total body protein (TBPr). Renutrition for patients with anorexia nervosa (AN) should aim to normalize body composition and to recover both fat mass and TBPr.

Objective

We intended to analyze predictors of protein status, including exercise status, in adolescents with AN and to investigate whether weight gain would replenish body protein deficits.

Methods

We assessed TBPr in a longitudinal, observational study as height-adjusted nitrogen index (NI) using in vivo neutron activation analysis in 103 adolescents with AN [mean ± SD age, 15.6 ± 1.4 y; body mass index (BMI, in kg/m2), 16.5 ± 1.6] at the commencement of inpatient refeeding (T0), in 56 of these patients 7 mo thereafter as outpatients (T1), and in age-matched controls (C; n = 51, 15.5 ± 2.1 y, BMI 20.7 ± 1.9). Lean tissue and fat mass were assessed by dual-energy X-ray absorptiometry. BMI, BMI standard deviation score, and lean tissue mass were tested as predictors of protein status using receiver operating characteristic analysis.

Results

At T0, NI was decreased in AN (AN, 0.88 ± 0.10 compared with C, 1.00 ± 0.08, P < 0.001). In 34%, the patients showed protein depletion. Patients classified as ``exercisers'' had a higher NI than did ``nonexercisers'' (0.89 ± 0.11 compared with 0.85 ± 0.08, P = 0.045). BMI, BMI standard deviation score, and lean tissue mass did not show potential as predictors of protein status. Despite increases in weight (+6.9 ± 4.5 kg), and BMI (+2.5 ± 1.7), protein status did not improve (TBPr T0, 8.0 ± 1.1 kg; T1, 8.1 ± 1.0 kg, P = 0.495). In an AN subgroup at 7 mo matched with controls in age (AN, 16.5 ± 1.1 y; C, 16.2 ± 1.8 y) and BMI (AN, 20.5 ± 1.4; C, 20.7 ± 1.3), protein status was still not normalized in AN (NI: AN, 0.89 ± 0.09 compared with C, 1.00 ± 0.07, P < 0.001).

Conclusions

Adolescents recovering from AN remained protein depleted at 7 mo after baseline assessment, even though they were weight restored.

Body composition estimation in children and adolescents by bioelectrical impedance analysis: A systematic review

BACKGROUND

Bioelectrical impedance analysis (BIA) has commonly been used to assess the body composition of children and adolescents. BIA validation studies have found distinct correlation values with reference methods.

OBJECTIVES

To assess the reproducibility, correlation and mean differences in body composition estimated by BIA and reference methods, we systematically reviewed the literature in the pediatric population.

METHOD

The search for articles was conducted in March 2016 and was limited to articles published from 2005 to 2015 in the PubMed, Embase, EBSCO, Web of Science, Scopus and SciELO databases. Two reviewers independently performed data selection and extraction of studies that investigated the BIA validity, responsiveness, reliability and/or measurement error (reproducibility) to estimate body composition in children and adolescents with an average age ≤ 18 years.

RESULTS

The search produced 48 articles. Almost perfect reproducibility was found in the body fat percentage estimated by BIA, and there was almost perfect correlation between the BIA ratings and reference methods for fat mass and fat-free mass. Regarding component estimates, BIA underestimated the fat mass in both sexes.

CONCLUSIONS

The body fat percentage estimated by BIA exhibited almost perfect reproducibility. The fat mass and fat-free mass estimated by BIA correlated almost perfectly with the reference methods in both sexes. BIA underestimated the fat mass in both sexes.

Outcomes of a rapid refeeding protocol in Adolescent Anorexia Nervosa

BACKGROUND

The impact of severe malnutrition and medical instability in adolescent Anorexia Nervosa (AN) on immediate health and long-term development underscores the need for safe and efficient methods of refeeding. Current refeeding guidelines in AN advocate low initial caloric intake with slow increases in energy intake to avoid refeeding syndrome. This study demonstrates the potential for more rapid refeeding to promote initial weight recovery and correct medical instability in adolescent AN.

METHODS

Seventy-eight adolescents with AN (12-18 years), hospitalised in two specialist paediatric eating disorder units, for medical instability (bradycardia, hypotension, hypothermia, orthostatic instability and/or cardiac arrhythmia) were followed during a 2.5 week admission. Patients were refed using a standardised protocol commencing with 24-72 hours of continuous nasogastric feeds (ceased with daytime medical stability) and routine oral phosphate supplementation, followed by nocturnal feeds and a meal plan of 1200-2400 kcal/day aiming for a total caloric intake of 2400-3000 kcal/day. Along with indicators of medical stability, weight, phosphate and glucose levels were recorded.

RESULTS

All patients gained weight in week one (M = 2.79 kg, SD = 1.27 kg) and at subsequent measurement points with an average gain of 5.12 kg (SD = 2.96) at 2.5 weeks. No patient developed hypophosphatemia, hypoglycaemia, or stigmata of the refeeding syndrome.

CONCLUSIONS

The refeeding protocol resulted in immediate weight gain and was well tolerated with no indicators of refeeding syndrome. There were no significant differences in outcomes between the treatment sites, suggesting the protocol is replicable.

TRIAL REGISTRATION

Australian Clinical Trials Register number: ACTRN012607000009415.

Regional fat distribution in adolescent and adult females with anorexia nervosa: A longitudinal study

BACKGROUND & AIMS

No study has yet compared body fat distribution before and after weight restoration in adolescent and adult patients with anorexia nervosa (AN) treated according to the same protocol. The study was set up to measure body fat distribution before and after short-term weight restoration in adolescent and adult patients with AN treated according to the same protocol in a specialist inpatient unit.

METHODS

We recruited 33 consecutive adolescent female patients with AN, and 33 controls matched by age and post-treatment BMI centile, as well as 33 adult female patients with AN, and 33 controls matched by age and post-treatment BMI. Dual-energy X-ray absorptiometry (DXA) was used to assess body composition before and after short-term weight restoration (BMI ≥ 18.5 kg/m²).

RESULTS

Compared with controls, both adolescents and adults with AN showed that a greater amount of fat was lost from the extremities than the trunk before weight restoration, and that there was a central adiposity phenotype after short-term weight restoration. There were no significant differences in body fat distribution between adolescents and adults with AN before or after short-term weight restoration.

CONCLUSIONS

Adolescent and adult females with AN have similar body fat distribution both before and after short-term weight restoration, and show a central adiposity phenotype after short-term weight restoration. The clinical implications of this finding are as yet unknown. Clinical Trials Registry- Regional Fat Distribution in Adolescent Girls and Adults with Anorexia Nervosa (ISRCTN73572502).

Nutritional care in children with cystic fibrosis: are our patients becoming better?

Over the last 30 years, major advances have occurred in our understanding of the disorder cystic fibrosis (CF) with the discoveries of the underlying chloride transport defect and the 'CF gene', the CF transmembrane conductance regulator gene. Equally important from a clinical and patient perspective are the improvements in median survival from less than 10 to 20 years prior to 1980, approaching 30 years during the 1980s and over 45 years more recently. Improved antibiotic regimens and lung clearance therapy contributed to the enhanced survival, but a key factor accredited as adding a further 10 years to the median survival was improving and then maintaining normal growth and nutrition. In the main, the latter were achieved by adherence to a 'high-fat high-energy' diet rather than the advocated virtually universal policy of the 'low fat', which was associated with wasting and linear growth failure. The high-fat diet in conjunction with better control of malabsorption due to microspheric pancreatic enzyme replacement therapy, attention to adequate fat-soluble vitamin supplementation and newborn screening has ensured that at least 80-90% of children with CF will achieve better health and survival through their adult years.

Beyond the BMI: the search for better guidelines for bariatric surgery

The application of the BMI of > or =35 as the major prerequisite for access to bariatric surgery is no longer appropriate because the index, now incorporated in the requirements of Medicare, Medicaid and most private carriers, does not reflect the degree or distribution of adiposity, it discriminates unfairly on the basis of gender, race, age, fitness, and body fat composition. Further, with increasing evidence that bariatric surgery can also induce full and durable remission of such comorbidities as type 2 diabetes even in patients with BMIs <30, new guidelines must be pursued.

Body composition changes in female adolescents with anorexia nervosa

BACKGROUND

Body weight provides limited information about nutritional status of patients with anorexia nervosa (AN).

OBJECTIVES

Our objectives were to determine body composition (BC) changes, to find clinical predictors and endocrine correlates of total body protein (TBPr) depletion, and to compare results on fat mass (FM) obtained with anthropometry (skinfold measurements) and dual-energy X-ray absorptiometry (DXA) in patients with AN.

DESIGN

Body weight, body mass index (BMI; in kg/m(2)), BC (with DXA and skinfold measurements), and TBPr [with in vivo neutron activation analysis (IVNAA)] was assessed in 50 AN patients (15.2 y) and 40 healthy sex- and age-matched controls. In 47 AN patients and 22 controls, hormone concentrations were measured.

RESULTS

In AN patients, body weight (44.4 +/- 5.5 kg), BMI (16.7 +/- 1.6), and FM(DXA) (7.0 +/- 3.4 kg) were lower than in controls. Lean tissue mass by DXA (LTM(DXA)) was similar in AN patients and controls (35.7 +/- 4.3 compared with 35.8 +/- 4.5 kg), but TBPr was 87% of that of controls (8.1 +/- 1.0 compared with 9.2 +/- 1.2 kg; P < 0.001). Cortisol was high, testosterone was unchanged, and estradiol and insulin-like growth factor I were low. Severe protein depletion measured by IVNAA seen in 17 AN patients could not be identified with simpler methods. All except 1 of 26 AN patients with a BMI > 16.5 had normal TBPr. The difference in individual percentage of body fat measured with DXA and skinfold measurements came up to 9%.

CONCLUSION

The severe protein depletion in 34% of AN patients was not accurately identified by LTM(DXA) or simpler methods, but a BMI > 16.5 indicated normal TBPr. Future studies need to compare DXA and skinfold measurements with a reference technique to assess FM in AN patients.

Body composition methods: comparisons and interpretation

The incidence of obesity in the United States and other developed countries is epidemic. Because the prevalence of comorbidities to obesity, such as type 2 diabetes, has also increased, it is clear there is a great need to monitor and treat obesity and its comorbidities. Body composition assessments vary in precision and in the target tissue of interest. The most common assessments are anthropometric and include weight, stature, abdominal circumference, and skinfold measurements. More complex methods include bioelectrical impedance, dual-energy X-ray absorptiometry, body density, and total body water estimates. There is no single universally recommended method for body composition assessment in the obese, but each modality has benefits and drawbacks. We present here the most common methods and provide guidelines by way of examples to assist the clinician/researcher in choosing methods appropriate to their situation.