Sex-Specific Pathways Lead to Statural Growth Impairment in Children with Crohn's Disease.

Objectives: To examine the underlying mechanisms that lead growth impairment to occur more commonly in males than females with Crohn's disease (CD).

Study Design: Children and adolescents with CD were enrolled in a prospective multicenter longitudinal cohort study. Height Z-score difference was computed as height Z-score based on chronological age (height chronological age-Z-score) minus height Z-score based on bone age (height bone age-Z-score) using longitudinal data. Specific serum cytokines were measured, hormone Z-scores were calculated based on bone age (bone age-Z), and their longitudinal associations were examined.

Results: There were 122 children with CD (63% male) who completed 594 visits. The mean ± SD chronological age was 11.70 ± 1.79 years. The mean ± SD height chronological age-Z-score was -0.03 ± 0.99 in males and -0.49 ± 0.87 in females. The mean ± SD height bone age-Z-score was 0.23 ± 0.93 in males and 0.37 ± 0.96 in females. The magnitude of the mean height Z-score difference was greater in females (-0.87 ± 0.94) than males (-0.27 ± 0.90; P = .005), indicating growth was better in females than males. The following negative associations were identified: in females, interleukin (IL)-8 (P < .001) and IL-12p70 (P = .035) with gonadotropin-bone age-Z-scores; IL-8 (P = .010), IL-12p70 (P = .020), and interferon-γ (P = .004) with sex hormone-bone age-Z-scores, and IL-8 (P = .044) and interferon-γ (P < .001) with insulin-like growth factor 1-bone age-Z-scores; in males, IL-1 beta (P = .019) and IL-6 (P = .025) with insulin-like growth factor 1-bone age-Z-scores.

Conclusions: Our data suggest that sex-specific molecular pathways lead to growth impairment in children with CD (primarily growth hormone/insulin-like growth factor-1 axis in males and primarily hypothalamic-pituitary-gonadal axis in females). Mapping these sex-specific molecular pathways may help in the development of sex-specific treatment approaches targeting the underlying inflammation characteristic of CD.