Endocrinology and Metabolism

Chronic inflammation and the effect of IGF-I on muscle strength and power in older persons

Michelangela Barbieri, Luigi Ferrucci, Emilia Ragno, Annamaria Corsi, Stefania Bandinelli, Massimiliano Bonafè, Fabiola Olivieri, Simona Giovagnetti, Claudio Franceschi, Jack M. Guralnik, Giuseppe Paolisso


Deregulation of the inflammatory response plays a major role in the age-related decline of physical performance. The causal pathway leading from inflammation to disability has not been fully clarified, but several researches suggest that interleukin-6 (IL-6) causes a reduction of physical performance in elderly through its effect on muscle function. In vitro studies demonstrated that IL-6 inhibits the secretion of insulin-like growth factor I (IGF-I) and its biological activity, suggesting that the negative effect of IL-6 on muscle function might be mediated through IGF-I. We evaluated the joint effect of IGF-I and IL-6 on muscle function in a population-based sample of 526 persons with a wide age range (20–102 yr). After adjusting for potential confounders, such as age, sex, body mass index, IL-6 receptor, and IL-6 promoter polymorphism, IL-6, IGF-I, and their interaction were significant predictors of handgrip and muscle power. In analyses stratified by IL-6 tertiles, IGF-I was an independent predictor of muscle function only in subjects in the lowest IL-6 tertile, suggesting that the effect of IGF-I on muscle function depends on IL-6 levels. This mechanism may explain why IL-6 is a strong risk factor for disability.

  • muscle function
  • disability
  • aging
  • InCHIANTI Study
  • insulin-like growth factor I


  • Address for reprint requests and other correspondence: G. Paolisso, Dept. of Geriatric Medicine and Metabolic Diseases, IV Divisione di Medicina Interna, Piazza Miraglia 2, I-80138 Napoli, Italy (E-mail: giuseppe.paolisso{at}unina2.it).

  • The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

  • First published November 5, 2002;10.1152/ajpendo.00319.2002

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