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Height Sparing in Anorexia Nervosa?« Back to Volume 24, Issue 2, November 2008 - Table of Contents Reports of height in girls with anorexia nervosa (AN) have conflicted between stunting and sparing. While under-nutrition and low insulin-like growth factor (IGF)-I levels would be expected to stunt statural growth, high levels of growth hormone (GH), with its direct effects on the growth plate, and hypogonadism, resulting in delayed skeletal maturation, would be expected to preserve height. Towards a better understanding, Prabhakaran et al compared 110 girls with AN (mean duration of illness 11.6 ± 13.2 months) to 98 age-matched controls (aged 12-18 years); 63 girls with AN and 79 controls were followed prospectively for one year. Girls were premenarcheal at baseline; 25 girls had AN and 10 were controls. At baseline, girls with AN had significantly lower BMI (mean 18.5 ± 2.1 vs 22.0 ± 3.2 kg/m2, respectively), lower IGF-I levels (15.8% of girls with AN had IGF-I concentrations below the reference range and 52.6% had levels within the lowest quartile for pubertal stage, compared to 18.4% of the controls), and higher nadir GH levels on overnight sampling (mean 2.14 ± 1.17 vs 1.04 ± 1.01 ng/mL, respectively). Bone ages were similar, though the difference between bone age and chronologic age was lower by a few months in the AN group. Midparental target heights (based on parental reports) and baseline heights were slightly higher for the AN group than controls (the latter 164.3 ± 6.9 vs 162.5 ± 6.5 cm, respectively). Height parameters did not differ significantly between the groups at 12-month follow up. Associations between nadir GH levels and z-scores for both height and predicted adult height (by Bayley-Pinneau method) were stronger in immature subjects and in controls. For girls with AN, these height parameters were associated with IGF-I levels instead, and inversely with duration of illness. The one-year increase in height z-score for immature girls with AN was predicted by baseline delay in bone age relative to chronologic age. The authors concluded that hypogonadism (delayed skeletal maturation), not higher GH levels, preserves final height in girls with AN. The duration and severity of illness (and hence, IGF-I levels) also played an important role in height outcome. Editor’s CommentEndocrinologists are frequently consulted for the hypogonadism associated with AN. Patients’ families present with the chief complaint of amenorrhea and raise concerns over bone mineralization.1 While these are valid concerns, this paper supports the notion that treatment of the underlying disease process (ie, nutritional repletion and psychological correction of the distorted body image) is preferable to hormone replacement therapy, especially for girls who are still growing. The reader must keep in mind that the height outcomes found in this study are dependent on the duration and severity of illness and may not generalize to other groups. Adda Grimberg, MD Reference - (linked to
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Volume 26 Number 1
September 2010
www.GGHjournal.com
ISSN 1932-9032
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