Association Between Ghrelin and Body Weight Trajectory in Individuals With Anorexia Nervosa

IMPORTANCE: Individuals with anorexia nervosa maintain extremely low body weights despite elevations in the circulating orexigenic hormone ghrelin. Whether circulating levels of endogenous ghrelin are associated with weight gain in anorexia nervosa is unknown. OBJECTIVE: To examine the association between baseline ghrelin and future weight change in individuals with anorexia nervosa. DESIGN, SETTING, AND PARTICIPANTS: This prospective cohort study was conducted between April 1, 2014, and March 31, 2020, in the US. Girls and women aged 10 to 22 years were recruited from the greater Boston area from community and area treatment centers, enrolled, and followed up for 18 months. Statistical analyses were performed between January and August 2022. EXPOSURES: Presence or absence of anorexia nervosa and elevations in endogenous ghrelin. MAIN OUTCOMES AND MEASURES: Changes in age- and sex-standardized body mass index percentiles from baseline to 9- and 18-month follow-up were the main outcomes of interest. RESULTS: A total of 68 girls and young women (11 [16%] Asian, 4 [6%] Hispanic or Latina, 51 [75%] White [non–Hispanic or Latina], and 2 [3%] other race or ethnicity), including 35 with anorexia nervosa and 33 healthy controls of similar Tanner stage, were included in this study. Anorexia nervosa and healthy control groups were not statistically different by race and ethnicity, Tanner stage, number completing follow-up visits, and the duration between baseline and follow-up visits. At baseline, individuals with anorexia nervosa were slightly older (median [IQR], 20.1 [18.5-21.0] vs 18.7 [14.7-19.4] years; P = .005), had lower body mass index percentiles (median [IQR], 2.4 [0.3-4.7] vs 52.9 [40.4-68.3]; P < .001), and had elevated circulating ghrelin area under the curve composite index (median [IQR], 1389.4 [1082.5-1646.4] vs 958.5 [743.0-1234.5] pg/mL; P = .003) compared with healthy individuals. In linear mixed-effects regression analyses, baseline ghrelin was associated with prospective weight gain after adjusting for diagnosis, age, race, and duration of follow-up (odds ratio, 2.35; 95% CI, 1.43-3.73; P = .004). CONCLUSIONS AND RELEVANCE: In this cohort study, endogenous ghrelin was associated with longitudinal weight gain in individuals with anorexia nervosa. Further studies are warranted to confirm this result and examine its potential clinical utility in treatment development.