Hormonal Adaptations of the Pituitary Axis in Malnourished Adults: Clinical Associations

Abstract

Objective: Malnutrition reshapes the hypothalamic–pituitary system through caloric deficiency and inflammatory mechanisms. Low albumin levels may be associated with low fT3, LH and IGF-1. This study aimed to clinically interpret the functional alterations of malnutrition on endocrine pathways. 
Methods: In this single-center study, medical records of 71 adult inpatients diagnosed with malnutrition according to GLIM criteria between 2018 and 2024 were retrospectively analyzed. Anthropometric parameters, biochemical markers, and pituitary hormones were classified based on laboratory reference ranges. Statistical analyses included the Shapiro–Wilk test for normality, the Mann–Whitney U test for group comparisons, Spearman’s correlation for associations, and multivariable logistic regression (significance level α=0.05). Ethical approval was obtained. 
Results: The mean age of the patients was 74.6±14.0 years. Low sT3 levels were observed in 90% of patients and low sT4 in 38% of patients, while TSH remained within normal limits in 70%. IGF-1 levels were reduced in 92% of patients, while GH levels remained within or slightly above normal ranges. In multivariable logistic regression, a one standard deviation increase in albumin decreased the likelihood of low sT3 and LH, whereas a one standard deviation increase in CRP was associated with low IGF-1. A decrease in pituitary volume (hypoplasia/atrophy) was detected in 3 of the 8 patients who underwent MRI. 
Conclusions: Malnutrition is characterized by adaptive endocrine responses. The consistent associations of the patterns with albumin and CRP support the prioritization of nutritional rehabilitation and inflammation control in treatment; hormone replacement should be administered only when clear clinical indications are present. These findings highlight the impact of nutritional rehabilitation and inflammation control on hormonal responses and provide a foundation for future volumetric studies.

Keywords

• Malnutrition
• Pituitary hormones
• Endocrine adaptation
• Inflammation

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