Bone mineral density accrual determines energy expenditure with refeeding in anorexia nervosa and supersedes return of menses

Energy expenditure during nutritional rehabilitation: a scoping review to investigate hypermetabolism in individuals with anorexia nervosa

BACKGROUND

Weight gain and nutritional rehabilitation are essential first steps to achieve medical stabilization in anorexia nervosa, and frequent resistance to weight gain requires patients to consume high kilocalorie loads. Adaptive hypometabolism is common when patients begin treatment, and rebound hypermetabolism is suspected to be a significant barrier to weight gain. The aim of this review was to summarize existing data describing metabolic changes in anorexia nervosa during weight restoration. The reported findings challenge current hypotheses of weight gain resistance and highlight key areas for future research.

METHODS

Using scoping review guidelines, three databases were searched for studies investigating metabolic changes in anorexia nervosa before and after renourishment. Two reviewers systematically screened the titles and abstracts of 447 articles, and full-text versions of 106 studies were assessed for eligibility. A total of 36 studies were included for review. Data regarding the study description, sample population (including age, weight, BMI, duration of treatment, and caloric intake), and metabolic variable descriptions were extracted.

RESULTS

Female patients with anorexia nervosa from studies across 13 countries were included. Across the studies, average BMI increased from 13.7 kg/m2 at admission to 17.57 kg/m2. Patients presented to treatment with clinically reduced energy expenditure levels. After varying levels of nutritional rehabilitation and weight restoration, measured energy expenditure increased significantly in 76% of the studies. Energy expenditure values at the second timepoint increased to the standard range for normal weight female teenagers and adults. Despite these increases, the studies do not indicate the presence of a hypermetabolic state during renourishment. Additionally, all studies including both measured and predicted energy expenditure reported that predicted energy expenditure overestimated measured values.

CONCLUSION

This study provides a detailed evaluation of the literature investigating energy expenditure and metabolic rate in patients with anorexia nervosa before and following a period of renourishment. The findings from this review identify important gaps in the current beliefs of energy expenditure in anorexia nervosa and highlight a need for further exploration of metabolic alterations during weight restoration.

Time course and reaction types of serum IGF-1 and its relationship to BMI and leptin regarding inpatients with anorexia nervosa

OBJECTIVE

Anorexia nervosa (AN) is a severe mental disorder that is characterized by restriction of energy intake, low weight, and endocrine abnormalities. One of the known endocrine changes in relation to underweight is in the GH/IGF-I axis. The aim of the study was (a) to investigate longitudinal characteristics of the IGF-I-change during therapy and weight gain in adult AN, (b) to determine relationships between IGF-I and leptin, (c) to characterize patients with weak and pronounced hormonal reactions to underweight.

DESIGN

Data was assessed from 19 AN patients. Over the first two months, serum IGF-I concentrations were assessed on a weekly basis; thereafter on a monthly basis. The trend of IGF-I values over time was analyzed using individual growth models.

RESULTS

In total, n = 177 IGF-I measurements were analyzed. IGF-I increased significantly dependent on BMI (slope = 20.81, p < 0.001), not modulated by duration of disease. The increase in IGF-I was significantly related to the increase in leptin concentrations over time (slope = 15.57, p < 0.001). Patients with a weaker hormonal reaction to underweight were significantly older compared to patients with a pronounced hormonal reaction (t(17) = 3.07, p = 0.007).

CONCLUSIONS

During treatment, IGF-I change is clearly related to BMI as well as to leptin. Age appears to be associated with the IGF-I response to underweight.

Bone metabolism in adolescent girls with eating disorders and weight loss: independent effects of weight change, insulin-like growth factor-1 and oestradiol

Adolescents with eating disorders (ED) are at risk of developing osteoporosis if weight is not recovered. Previous investigations do not separate the effects of weight change per se from those of concomitant hormonal changes. In this investigation serum osteocalcin (OC), C-terminal telopeptide of collagen (CTX), insulin-like growth factor-1 (IGF-1) and oestradiol were measured at assessment of 498 girls with ED and during weight gain of 59 girls. At assessment, OC concentrations were associated independently with weight (change), IGF-1 and oestradiol. Low weight, a high rate of weight loss and the hormone concentrations were associated with low OC. Low weight and high rate of weight loss were associated with high CTX concentrations but there were no associations independent of weight (change) with the hormones. During weight recovery, OC and CTX were independently and positively associated with weight, weight gain, IGF-1 and oestradiol. Bone metabolism markers are related to weight change independently of IGF-1 and oestradiol during both weight loss and weight gain. During weight gain, when pubertal development and growth are resumed there is an additional independent positive association between the markers and IGF-1 and oestradiol. These relationships are strongest in premenarcheal girls.