Free Thyroid Hormone Profile and Its Association with Nutritional Status in Children with Severe Acute Malnutrition: A Cross-Sectional Study

Objective: To assess free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) concentrations in children with severe acute malnutrition (SAM) and to evaluate their associations with anthropometric indices and biochemical markers of protein status.

Methods: In this cross-sectional study, 68 children aged 6–59 months with SAM admitted to the pediatric ward of Deen Dayal Upadhyay Hospital, New Delhi (February 2024–March 2025) were enrolled. Anthropometric measurements including weight-for-height (WFH) Z-score and mid-upper arm circumference (MUAC) were recorded. Serum FT3, FT4, TSH, total protein, and albumin were measured. Statistical analysis was performed using R (version 4.5.1), and correlations were assessed using Spearman’s rank analysis.

Results: The median age was 18 months, with a male-to-female ratio of 0.75:1. The median WFH Z-score was −4.05, and the median MUAC was 113 mm, indicating severe wasting. Median FT3, FT4, and TSH concentrations were 312 pg/dL, 12 ng/L, and 2.39 mIU/L, respectively, within laboratory reference ranges. Mean total protein was 6.6 g/dL, while mean albumin was 3.26 g/dL. FT3 and FT4 showed significant positive correlations with MUAC, total protein, and albumin, whereas TSH demonstrated significant inverse correlations with free hormone levels and protein markers. WFH Z-score did not correlate significantly with biochemical parameters.

Conclusion: WFH Z-score and MUAC reflect different dimensions of the pathophysiology of SAM. The hypothalamic–pituitary–thyroid axis appears preserved in children with SAM. Free thyroid hormones (FT3 and FT4) rather than total thyroid hormones may provide a physiologically relevant evaluation of thyroid status in SAM children.