ORIGINAL ARTICLE Classification of pro-inflammatory status for interleukin-6 affects relative muscle strength in obese elderly women Dahan da Cunha Nascimento 1,2 • Nuno Manuel Frade de Sousa 3 • Ivo Vieira de Sousa Neto 1 • Ramires Alsamir Tibana 1 • Vinicius Carolino de Souza 1,4,5 • Denis Cesar Leite Vieira 1,2 • Nathalia Ferreira Camarc ¸o 1 • Sandra de Oliveira 1 • Jeeser Alves de Almeida 6 • James Navalta 7 • Jonato Prestes 1 Received: 9 December 2014 / Accepted: 5 March 2015 Ó Springer International Publishing Switzerland 2015 Abstract Background Obesity, defined by an excess amount of body fat or a percent body fat higher than 30 % for women is a complex chronic disorder with multifactorial etiology and is accompanied by chronic low-grade inflammation, which results in elevated pro-inflammatory cytokines. Aims The aim of this study was to compare muscle strength between high and low pro-inflammatory status in obese elderly women and to verify the relationship of IL-6 with muscle strength and fat-free mass. Methods Eighty-nine elderly women (age 69.47 ± 6.07 years; body mass 64.70 ± 12.04 kg; height 1.52 ± 0.06 m; body mass index 27.78 ± 4.75 kg/m 2 ) were di- vided into two groups: high and low inflammatory status for IL-6. Lower limb muscle strength was tested using bilateral leg extension with the ten repetitions maximum test, IL-6 was measured by ELISA and body composition by dual-energy X-ray absorptiometry. Results Women classified from the high pro-inflamma- tory status presented lower relative muscle strength (P = 0.056) when compared with the low inflammatory status group, with no differences for absolute muscle strength (P = 0.18). There was a significant negative cor- relation of IL-6 with relative muscle strength (P = 0.03, R =-0.22) and a considerable trend toward significance (P = 0.06, R =-0.19) and negative association with fat- free mass (P = 0.84, R =-0.02). Conclusions This study provides insights that a high pro- inflammatory status in sedentary obese elderly women might impair muscle strength and negatively affect fat-free mass. Thus, elderly women classified with high pro-in- flammatory status for IL-6 should receive further health care attention to prevent this deleterious condition. Keywords Inflammation Á Aging Á Interleukin-6 Á Muscle strength Introduction Overweight and obesity referred to an excess amount of body fat are leading risks for global death and ap- proximately 3.4 million adults die each year as a result of these chronic conditions. Body mass index (BMI) is an acceptable index method in younger adults, since it is correlated with body fat. However, in elderly subjects, it may be limited due to the loss of fat-free mass and height, while the relative adiposity, and specifically the intra-ab- dominal fat, continues to increase [1]. Dual-energy X-ray absorptiometry (DEXA) allows direct noninvasive & Dahan da Cunha Nascimento dahanc@hotmail.com Jonato Prestes jonatop@gmail.com 1 Graduation Program on Physical Education, Catholic University of Brasilia, Q.S. 07, Lote 01, EPTC, Bloco G, Taguatinga, Federal District, Brasilia 71966-700, Brazil 2 UDF - Centro Universita ´rio, Brasilia, DF, Brazil 3 Laboratory of Exercise Physiology, Faculty Estacio of Vitoria, Vitoria, ES, Brazil 4 Graduation Program in Gerontology, Catholic University of Brasilia, Brasilia, Brazil 5 Graduation Program in Medical Sciences, University of Brasilia, Brasilia, Brazil 6 Departamento de Educac ¸a ˜o Fı ´sica, Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, Brazil 7 Department of Kinesiology and Nutrition Sciences, University of Nevada, Las Vegas, NV, USA 123 Aging Clin Exp Res DOI 10.1007/s40520-015-0349-9