Deworming, Weight Gain, Linear Growth and the IGF-1 Axis in Children with Ascaris and Other Soil-Transmitted Helminth Infections: A Critical Narrative Review

Abstract

Soil-transmitted helminth (STH) infections remain concentrated in children living in settings where poverty, inadequate sanitation, recurrent enteric infection and undernutrition overlap. This convergence has encouraged a long-standing expectation that deworming should improve weight gain and linear growth. Yet the growth evidence is heterogeneous, and the biological pathway connecting worm clearance to somatic growth has rarely been examined directly. This critical narrative review evaluates evidence on Ascaris lumbricoides, Trichuris trichiura and hookworm infections, focusing on weight gain, height or length gain, and the growth hormone–insulin-like growth factor-1 (GH–IGF-1) axis. Literature was identified through PubMed, Europe PMC, OpenAlex, DOAJ, Semantic Scholar, Google Scholar, WHO resources and citation searching, with the principal search period extending to 8 August 2026 and older foundational studies retained where necessary. Randomised trials from high-intensity infection settings reported short-term improvements in weight and occasionally height after anthelminthic treatment, whereas larger and more recent population-level trials and evidence syntheses generally found little or no average effect of repeated mass deworming on weight or linear growth. The contrast is biologically plausible rather than necessarily contradictory: benefit is most likely when infection intensity is sufficient to impair appetite, nutrient utilisation, intestinal function, iron status or inflammatory homeostasis, and when these constraints are reversible within the observation period. Evidence linking STH infection specifically to the GH–IGF-1 axis is sparse. The strongest helminth-specific endocrine observations derive from Trichuris dysentery syndrome, where low IGF-1 and impaired collagen synthesis improved during recovery. Broader paediatric evidence shows that undernutrition, intestinal dysfunction and systemic inflammation can suppress IGF-1 signalling and linear growth. Current data therefore support a conditional model in which deworming removes one growth constraint but does not reliably overcome coexisting dietary, inflammatory and environmental constraints. Future trials should measure infection intensity, diet, inflammation, enteric dysfunction, IGF-1/IGFBP-3 and growth velocity together, enabling identification of children in whom parasite clearance can produce meaningful catch-up growth.