Vicinanza Roberto, Frizza Alessandro, Pollard Julie A, Mazza Valentina, De Martino Massimo Ulderico, Imbimbo Giovanni, Pignatelli Pasquale, Ettorre Evaristo, Del Ben Maria, Molfino Alessio
Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, United States.
Department of Clinical, Internal, Anesthesiologic and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy.
Front Nutr. 2025 Jun 24;12:1585696. doi: 10.3389/fnut.2025.1585696. eCollection 2025.
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).
One hundred thirty 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.
Ninety-one patients were included in the analysis. Mean age was 74.4 ± 7.2 years; 50.5% female. Mean BMI was 28 kg/m ± 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 ( = 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 ( = 0.317, = 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) ( = 0.024), Intracellular Water (ICW) ( = 0.018), FFM ( = 0.022), and Muscle Mass (MM) ( = 0.017), Body Cell Mass (BCM) ( = 0.046). Linear regression analysis showed that IGF-I and male sex predicted FFM ( = 13.933, < 0.001; = 0.040; = 0.034; respectively). The mediation analysis confirmed no significant direct effect of Vitamin D on FFM (direct effect, = -0.058, = 0.319, 95% CI: -0.175, 0.058); however, the effect was significant when mediated by IGF-I (indirect effect, = 0.039, SE = 0.022, 95% CI: 0.005, 0.091).
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.
胰岛素样生长因子I（IGF-I）和维生素D对生长和代谢至关重要，其水平会随着年龄增长而下降。然而，它们之间的相互作用以及对身体成分的影响仍不清楚。
研究老年门诊患者中IGF-I、维生素D与身体成分之间的关系，并检验IGF-I在维生素D与去脂体重（FFM）关联中的中介作用。
意大利罗马第一大学附属翁贝托一世综合医院老年门诊的130例患者符合研究条件。采用老年累积疾病评定量表（CIRS-G）评估多种疾病。使用生物电阻抗分析测量身体成分。评估全血细胞计数、代谢指标、IGF-I和25（OH）维生素D。
91例患者纳入分析。平均年龄为74.4±7.2岁；50.5%为女性。平均体重指数为28kg/m²±3.9。CIRS-G总分平均为14.14±4.1，严重程度指数（SI）为1.16±0.32。IGF-I中位数为122.0ng/mL（四分位间距，69.8），男性水平高于女性（P = 0.0096）。25（OH）维生素D平均为27.04ng/mL±14.69，无显著性别差异。25（OH）维生素D水平与IGF-I呈正相关（P = 0.317，P = 0.003），而维生素D与身体成分参数之间无相关性。IGF-I水平较高的患者表现出较高的总体水（TBW）（P = 0.024）、细胞内水（ICW）（P = 0.018）、FFM（P = 0.022）、肌肉量（MM）（P = 0.017）、身体细胞量（BCM）（P = 0.046）。线性回归分析显示，IGF-I和男性性别可预测FFM（P = 13.933，P < 0.001；P = 0.040；P = 0.034，分别）。中介分析证实维生素D对FFM无显著直接效应（直接效应，P = -0.058，P = 0.319，95%可信区间：-0.175，0.058）；然而，当由IGF-I介导时效应显著（间接效应，P = 0.039，标准误 = 0.022，95%可信区间：0.005，0.091）。
这些发现进一步证明了IGF-I与瘦体重之间存在正相关，并表明IGF-I可能介导维生素D对FFM的生理作用，突出了它们在评估衰弱前期和个性化营养干预中的潜在作用。
