ORIGINAL RESEARCH article

Front. Nutr.

Sec. Clinical Nutrition

Volume 12 - 2025 | doi: 10.3389/fnut.2025.1585696

This article is part of the Research TopicThe Relationship between Nutrition and Frailty/Multimorbidity: Prevention and Clinical Nutritional ManagementView all 18 articles

Aging and IGF-I: Relationships with Vitamin D and Body Composition. A Mediation Analysis

Provisionally accepted
Roberto  VicinanzaRoberto Vicinanza1,2*Alessandro  FrizzaAlessandro Frizza2Julie  A PollardJulie A Pollard1Valentina  MazzaValentina Mazza2Massimo Ulderico  De MartinoMassimo Ulderico De Martino3Giovanni  ImbimboGiovanni Imbimbo2Pasquale  PignatelliPasquale Pignatelli2Evaristo  EttorreEvaristo Ettorre2Maria  Del BenMaria Del Ben2Alessio  MolfinoAlessio Molfino2
  • 1University of Southern California, Los Angeles, United States
  • 2Sapienza University of Rome, Rome, Lazio, Italy
  • 3University of Salerno, Fisciano, Campania, Italy

The final, formatted version of the article will be published soon.

Background: Insulin-like Growth Factor I (IGF-I) and Vitamin D are crucial for growth and metabolism, with their levels declining with age. However, their mutual interactions and contributions to body composition remain unclear.To examine the relationships between IGF-I, Vitamin D, and body composition in geriatric outpatients, and to test the mediational role of IGF-I in the association between Vitamin D and Fat-Free Mass (FFM).Methods: 130 patients were eligible at the Geriatric Outpatient Clinic at the Policlinico Umberto I, Sapienza University of Rome, Italy. Multimorbidity was evaluated with the Cumulative Illness Rating scale for Geriatrics (CIRS-G). Body composition was measured using bioelectrical impedance analysis. Complete blood count, metabolic panel, IGF-I, and 25(OH) Vitamin D were assessed.Results: 91 patients were included in the analysis. Mean age was 74.4 ± 7.2 years; 50.5% female. Mean BMI was 28 kg/m 2 ± 3.9. Mean CIRS-G total score was 14.14 ± 4.1, and Severity Index (SI) was 1.16 ± 0.32. Median IGF-I was 122.0 ng/mL (IQR, 69.8) with higher levels in males compared to females (p = 0.0096). Mean 25(OH) Vitamin D was 27.04 ng/mL ± 14.69 with no significant sex difference. Level of 25(OH) Vitamin D positively correlated with IGF-I (ρ = 0.317, p = 0.003), while no correlation was found between Vitamin D and body composition parameters. Patients with higher IGF-I exhibited higher Total Body Water (TBW) (p = 0.024), Intracellular Water (ICW) (p = 0.018), FFM (p=0.022), and Muscle Mass (MM) (p=0.017), Body Cell Mass (BCM) (p=0.046). Linear regression analysis showed IGF-I and male sex predicted FFM (B=13.933, p<0.001; B = 0.040; p = 0.034; respectively). The mediation analysis confirmed no significant direct effect of Vitamin D on FFM (direct effect, B = -0.058, p = 0.319, 95% CI: -0.175, 0.058); however, the effect was significant when mediated by IGF-I (indirect effect, B = 0.039, SE = 0.022, 95% CI: 0.005, 0.091).Conclusions: These findings provide further evidence of a positive correlation between IGF-I and lean body mass and suggest that IGF-I may mediate the physiological effect of Vitamin D on FFM, highlighting their potential roles in assessing pre-frailty and personalizing nutrition interventions.

Keywords: Aging, Body Composition, Fat-free mass, Frailty, IGF-I, multimorbidity, pre-frailty, Vitamin D

Received: 01 Mar 2025; Accepted: 30 May 2025.

Copyright: © 2025 Vicinanza, Frizza, Pollard, Mazza, De Martino, Imbimbo, Pignatelli, Ettorre, Ben and Molfino. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Roberto Vicinanza, University of Southern California, Los Angeles, United States

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