Robert Gotshall, PhD. Alexander ... Robert Robergs, PhD. Chantal ..... Idland G, Pettersen R, Avlund K, Bergland A. Physical performance as long-term predictor ...
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Journal of Exercise Physiologyonline April 2018 Volume 21 Number 2
Editor-in-Chief Official Research Journal of the American Society of Tommy Boone, PhD, MBA Review Board Exercise Physiologists Todd Astorino, PhD ISSN 1097-9751 Julien Baker, PhD Steve Brock, PhD Lance Dalleck, PhD Eric Goulet, PhD Robert Gotshall, PhD Alexander Hutchison, PhD M. Knight-Maloney, PhD Len Kravitz, PhD James Laskin, PhD Yit Aun Lim, PhD Lonnie Lowery, PhD Derek Marks, PhD Cristine Mermier, PhD Robert Robergs, PhD Chantal Vella, PhD Dale Wagner, PhD Frank Wyatt, PhD Ben Zhou, PhD
JEPonline Physical Activity Level, Muscle Strength, Serum Levels of IGF-1 and Components of the Frailty Syndrome in the Elderly Ignácio Antônio Seixas-da-Silva1,3, Ana Beatriz Winter Tavares2,3, Maria Lucia Fleiuss de Farias3, Mario Vaisman3, Rodrigo Gomes de Souza Vale1, Flávia Lúcia Conceição3, Rodolfo de Alkmim Moreira Nunes1 1
Rio de Janeiro State University (UERJ) - Institute of Physical Education and Sports - RJ, Brazil, 2Rio de Janeiro State University (UERJ) - Endocrine Service of Pedro Ernesto University Hospital RJ, Brazil, 3Federal University of Rio de Janeiro (UFRJ) - Endocrine Service of Clementino Fraga Filho University Hospital - RJ, Brazil ABSTRACT
Official Research Journal of the American Society of Exercise Physiologists
ISSN 1097-9751
Seixas-da-Silva IA, Tavares ABW, Farias MLF, Vaisman M, Vale RGS, Conceição FL, Nunes RAM. Physical Activity Level, Muscle Strength, Serum Levels of IGF-1 and Components of the Frailty Syndrome in the Elderly. JEPonline 2018;21(2):182-192. The purpose of this study was to observe the correlations between physical activity level, muscle strength, serum levels of IGF-1, and components of the frailty syndrome. The level of physical activity was assessed using the IPAQ, the IGF-1 levels were determined in serum samples, body composition was determined using DXA, and the grip strength, gait speed, and energy expenditure at rest were considered as the criteria for the Frailty Syndrome. The sample consisted of 41 elderly individuals divided into 2 subgroups: (a) the first group presenting 1 criterion; and (b) the second group consisted of 2 or more criteria. A prevalence of frailty in 34% of the sample was found, the serum level of IGF-1 was not correlated with any parameter. However, the handgrip strength test may be applied as a tool to assess the functional capacity of the individual. Key Words: Aging, Frailty, Physical Activity
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INTRODUCTION Frailty is defined as a medical syndrome with multiple causes and contributors. It is characterized by diminished strength, endurance, and reduced physiologic function that increases an individual’s vulnerability for developing increased dependency and/or death (21). Aging is associated with sarcopenia, decreased bone mass, greater risk of fractures, increased visceral fat, decreased exercise capacity, and reduced quality of life (28). The decrease in body mass, strength, endurance, balance, walking, and a lifestyle that decreases the ability to perform activities of daily living (ADL) are some manifestations that identify the frailty syndrome (1,8,9). When considering 5 components, individuals with 3 or more components of the phenotype meet the criteria for frailty, while individuals with 1 or 2 components have a high risk for developing the syndrome (17,34). Insulin-like growth factor-1 (IGF-1) plays an important neurophysiological function, as it participates in increases in myelin synthesis, neuronal growth and development, protein synthesis, and muscle fiber reinnervation (neurotrophic factor). It stimulates the incorporation of chondroitin sulfate by stimulating osteoblast activity and bone matrix preservation (22,27). It also is the main mediator of the anabolic effects of the growth hormone (GH). IGF-1 is produced by the liver, and is regulated by the GH concentration, nutritional status, body composition, and hormone and metabolite concentrations (6). Frailty syndrome (FS) has become increasingly a health problem in older individuals. Thus, to better understand FS and its treatment, the purpose of this study was to determine the correlation between physical activity level, muscle strength, serum levels of IGF-1, and components of FS in the elderly. METHODS Subjects The sample consisted of 41 elderly individuals, geriatric outpatients, whom were recruited to voluntarily participate in the Clementino Fraga Filho University Hospital of the Federal University of Rio de Janeiro (HUCFF). The subjects were divided into 2 subgroups: (a) the first group consisted of individuals presenting 1 criterion for frailty syndrome; and (b) the second group consisted of individuals presenting 2 or more criteria for the syndrome. The inclusion criteria consisted of being a patient of the geriatric ambulatory at the HUCFF and older than 65 yrs of age. The exclusion criteria were: (a) history of mental illness; (b) decompensated diabetes mellitus and hypertension; (c) use of medications that affect the somatotropic axis; (d) use of GH 1 yr before the initial evaluation; and (e) the presence of physical limitations that would prevent the execution of the protocols adopted in the study. Informed consent was obtained from each subject without any refusals, and the experimental procedures were executed in accordance with the World Medical Association Declaration of Helsinki (33). The research project for this study was approved by the Committee of Ethics in Research Involving Human Beings of the Federal University of Rio de Janeiro (protocol number: 185/09).
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Procedures IGF-1 levels were determined in serum samples using the Liaison® IGF-1 chemiluminescent assay kit (DiaSorin) with a measurement range of 3 to 1500 ng·mL-1. Body composition was determined using dual-energy X-ray absorptiometry (DXA) from Prodigy Advance PlusLUNAR® Corp/General Electrics/USA. Body mass (kg) and height (cm) were measured to calculate body mass index (BMI, expressed in kg·m-²). Grip strength, gait speed, and energy expenditure at rest were considered as phenotypic criteria for frailty syndrome because it is a simple and fast form of tests that can be applied in the clinical area. Also, the three tests are related to physical performance, which is an important factor in function autonomy. Handgrip strength was the first muscle test performed, using the JAMAR® dynamometer (Hydraulic Hand Dynamometer - Model PC-5030J1, Fred Sammons, Inc., Burr Ridge, IL, USA) according to the recommendations of the American Society of Hand Therapists (16). The final measurement, in kilogram-force (kgf), was obtained by calculating the mean of 3 measurements performed with the subject’s dominant hand. The second test performed was gait speed, where the 4-m walk test proposed by Guralnik et al. was used (12). Resting energy expenditure (REE) was calculated according to the method proposed by Harris and Benedict, with the values expressed in kilocalories (kcal) and cutoffs of 383 kcal for men and 270 kcal for women (7,8). The autonomy of the elderly was identified by the quadriceps strength, which was measured using an IsoTeste Kroman-Thrigger® electromechanical dynamometer chair (values expressed in kgf), with 3 attempts for each leg. The means were calculated and the values were expressed as percentages of the predicted values for age, gender and dominance, height and body mass (29). The level of physical activity was assessed using the International Physical Activity Questionnaire (IPAQ) modified for the elderly. This questionnaire assesses the level of physical activity in 5 domains: job-related physical activity; transportation physical activity; physical activity at home or in an apartment (i.e., housework, house maintenance and caring for family); recreation, sports, exercise and leisure physical activities; and time spent sitting (2,19). Statistical Analyses The Student t-test was used to assess the parametric data using means ± standard deviations for the descriptive statistics. The Mann-Whitney test was used to assess nonparametric data using medians for the descriptive statistics. The Spearman test was used for nonparametric analysis of correlations between non-homogeneous data with all items assessed, where the values for distributions and correlation coefficients and significance levels were obtained. The chi-square test (X2) was used to compare the observed frequencies among the evaluated parameters. The value of significance for α in all calculations was set at P≤0.05 and the IBM® SPSS 20 software was used for the statistical analysis between the variables RESULTS The sample included 41 elderly individuals (N = 41), of whom 36 were women and 5 were men. After dividing the sample by the criteria of frailty, the Non-Frail Group consisted of 27
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elderly with 23 women (85.19% of the sample) and 4 men (14.81% of the sample), while the Frail Group consisted of 14 individuals with 13 women (92.86% of the sample) and 1 man (7.14% of the sample). Table 1 shows the values of the descriptive statistics of the parametric data of the total sample and the 2 groups. Table 2 shows the values of the descriptive statistics for nonparametric data of the total sample and the 2 groups. Table 1. The Means and Standard Deviations for the Parametric Data of the Sample. P Variables Total Group Non-Frail Group Frail Group N
41
27
14
77.5 ± 5.4
81.7 ± 6.19
0.031*
Age (yrs)
79 ± 5.96
Height (m)
1.5 ± 0.08
1.5 ± 0.06
1.5 ± 0.11
0.188
Body Mass (kg)
64.8 ± 10.28
65.7 ± 9.11
62.7 ± 12.36
0.374
BMI (kg·m-²)
28.4 ± 3.33
28.3 ± 3.22
28.2 ± 3.65
0.933
41 ± 6.62
41.7 ± 6.36
39.7 ± 7.15
0.365
Fat Mass (kg)
25.3 ± 6.43
26.3 ± 6.21
23.3 ± 6.61
0.162
Lean Mass (kg)
36.2 ± 6.68
36.3 ± 5.12
35.7 ± 9.19
0.773
%F
BMI = Body Mass Index; % F = Fat Percentage. * P≤0.05 comparing the 2 groups
Table 2. Median Values for the Nonparametric Data of the Sample. Variables
P
Total Group
Non-Frail Group
Frail Group
41
27
14
37.2
37.2
37.2
0.596
UL Muscle Mass (kg)
3.4
3.4
3.3
0.347
LL Muscle Mass (kg)
11.3
11.4
11.2
0.269
9.0
10.0
7.8
0.204
RLL Strength (kgf)
27.8
30.4
23.9
0.081*
LLL Strength (kgf)
24.4
25.5
18.6
0.185
Gait Speed (sec)†
5.9
4.9
9.8
0.000*
REE (kcal)
892.0
895.6
850.9
0.333
IGF-1 (ng·mL-1)
135.7
135.7
128.3
0.817
N Fat-Free Mass (kg)
Hand Grip Strength (kgf)†‡
†
UL = Upper Limbs; LL = Lower Limbs; RLL = Right Lower Limb; LLL = Left Lower Limb; REE = Resting Energy Expenditure; IGF-1 = Insulin-like Growth Factor 1. ‡ Relative to the mean value of handgrip. † Criteria used to determine frailty. * P≤0.05 comparing the 2 groups.
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A median value of IGF-1 was 135.7 ng·mL-1 in the total group. The same value was detected in the Non-Frail Group, while a median value of 128.3 ng·mL-1 was found in the Frail Group. Statistical analysis revealed no correlations or significant differences between serum levels of IGF-1 and the assessed variables. This study showed a correlation between the handgrip strength values (the component of physical frailty present in most tests for identifying FS) and the lower limb strength values (P
