Endocrine and Bone Metabolism at Baseline in Adolescent Girls with Restrictive Anorexia Nervosa
A Retrospective Cohort Study.
Martine K.F. Docx 1, Annik Simons 2, Daniel Klink 3
1 Pediatrician-Chronic Pediatric Diseases-Eating Disorders Independent Researcher Antwerp, Belgium; 2 Department of Children and Adolescent Psychiatry UKJA-ZAS Antwerp Belgium, 3 Department of Pediatric Endocrinology ZAS, Antwerp, Belgium
EATING DISORDER RESEARCH VAE 2026 ANTWERP
134
participants
14.5 y
mean age
15.4
mean BMI
100%
female
Background and Objective
Adolescents with anorexia nervosa (AN) face impaired bone accrual during a critical growth window. We summarized anthropometric, skeletal maturation, and biochemical data from a female adolescent AN cohort and explored how these measures related to nutritional status.
Methods
• Retrospective analysis of an anonymized spreadsheet dataset (2013-2019)
• Female adolescents with AN; one row per participant
• “ND” treated as missing
• Descriptive statistics plus exploratory Spearman correlations
• DEXA field noted whether a scan was performed; no quantitative BMD values were available
Cohort Summary
Metric
Value
Participants
134
Female sex
134 (100%)
Age, mean ± SD
14.5 ± 1.6 y
BMI, mean ± SD
15.4 ± 1.9 kg/m²
IGF-1 available
86/134 (64%)
Bone age available
74/134 (55%)
DEXA recorded as performed
60/134 (45%)
Data Completeness
Key Limitation
Interpretation is limited by substantial missingness, especially for cortisol, calcitonin, and PTH. Quantitative DEXA outcomes were not available.
Nutritional Status
BMI values clustered around 15 kg/m², corresponding to a mean BMI-SDS of −2.1, consistent with marked undernutrition across the cohort. Nearly two-thirds of participants were below −2 SD, and one-fifth below −3 SD, indicating severe malnutrition in a substantial subgroup..
BMI and IGF-1
Lower BMI was associated with lower IGF-1 (Spearman ρ = 0.43, p < 0.001).
Interpretation
The positive BMI-IGF-1 association is consistent with suppression of the anabolic growth axis in undernourished adolescents with AN. Routine calcium and phosphate remained relatively clustered despite this signal.
Selected Descriptive Statistics
Metric
Value
IGF-1, median [IQR]
116.5 [81.2-163.5]
Bone age, median [IQR]
15.0 [13.1-16.0] y
Calcium, median [IQR]
4.8 [4.7-4.9]
Phosphate, median [IQR]
2.7 [2.5-2.9]
25-OH vitamin D, median [IQR]
28.0 [22.0-37.0]
Mean age was 14.46 ± 1.61 years and mean BMI 15.43 ± 1.90 kg/m², corresponding to a mean BMI-SDS of −2.1 ± 0.8. 63% were below −2 SD and 21% below −3 SD.�IGF-1 (n=85) showed a significant positive association with BMI (Pearson r=0.374, p=0.00043; Spearman rho=0.429, p=0.00004). Patients with BMI <15 had significantly lower IGF-1 levels than those with BMI ≥15 (111.9 vs 148.7; p=0.0021).�Bone age (n=74) demonstrated marked variability, with a mean difference of +0.05 ± 1.07 years, while 40.5% showed delayed bone age.�Calcium and phosphate levels were generally within normal ranges. No significant associations were observed between BMI and vitamin D or cortisol, although these analyses were limited by missing data.�
Skeletal Maturation
Bone age generally paralleled chronological age in the available subset.
Biochemical Bone Markers
Conclusions
• Lower BMI coincided with lower IGF-1, supporting nutritional suppression of the growth axis.�• Bone age broadly approximated chronological age in the subset with available data, although individual variation remained.�• Routine minerals were relatively clustered, whereas vitamin D and alkaline phosphatase were more variable. �Adolescent girls with restrictive anorexia nervosa present with severe undernutrition and a strong relationship between BMI and IGF-1, reflecting endocrine adaptation. Bone maturation is heterogeneous, with delayed development in a substantial subgroup. These findings support early endocrine and skeletal assessment at diagnosis.�• Age-adjusted anthropometric severity was confirmed by a mean BMI-SDS of −2.1.�• Prospective studies with quantitative DEXA outcomes and longitudinal follow-up are needed.
Correspondence Adress : Martine KF Docx Zeebruggestraat 57 2500 Lier
No conflicts of interest declared.
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Poster size: A0 landscape