RhIGF-1 use confers no added benefit vs oestradiol alone in anorexia nervosa

Administration of recombinant human insulin-like growth factor-1 (rhIGF-1) for 12 months does not appear to provide additional benefit over transdermal oestrogen replacement alone in a cohort of young women with anorexia nervosa, a study has shown.

Seventy-five adolescent and young adult women with anorexia nervosa (aged 14 to 22 years) were included in this double-blind, randomized, placebo-controlled 12-month longitudinal study. Thirty-three of them completed the trial.

The investigators administered transdermal 17-beta oestradiol 0.1 mg/day with 30 mcg/kg/dose of rhIGF-1 subcutaneously twice daily (AN-IGF-1+) or placebo (AN-IGF-1–), with the dose of rhIGF-1 adjusted to maintain levels in the upper half of the normal pubertal range. The main outcome measures were bone turnover markers and bone density, geometry, microarchitecture, and strength estimates.

Lumbar areal bone mineral density (BMD) increased over 12 months in AN-IGF-1– relative to AN-IGF-1+ (p=0.004). The latter also did not show improvement in areal BMD in the setting of variable compliance to oestrogen treatment.

Twelve-month changes in bone geometry, microarchitecture, volumetric BMD, or strength did not differ between groups; results did not change as well after controlling for weight changes. Increases were recorded in radial cortical area and volumetric BMD as well as tibia cortical volumetric BMD in both group over 12 months.

The AN-IGF-1– cohort showed a decrease in levels of a bone resorption marker (p=0.042), while the AN-IGF-1+ demonstrated an increase in parathyroid hormone (p=0.019). Women in the AN-IGF-1– arm also had irregular menses more frequently than did those in the AN-IGF-1+ arm, but no between-group difference was noted in the incidence of other adverse events.

“Anorexia nervosa is prevalent in adolescent girls and is associated with bone impairment driven by hormonal alterations in nutritional deficiency,” the investigators said.