Abstract
OBJECTIVE:
Asthma may cause systemic repercussions due to its severity and the effects of treatment. Our objective was to compare posture, balance, functional capacity, and quality of life (QOL) according to the severity of disease, as assessed by pulmonary function levels.
METHOD:
This cross-sectional study evaluated fifty individuals with asthma. We compared two groups of adult individuals who were divided according to the median of the forced expiratory volume in one second (FEV1) as follows: group A = FEV1>74% predicted; group B = FEV1<74% predicted. All patients underwent the following tests: spirometry, whole-body plethysmography, diffusing capacity for carbon monoxide (DLco), respiratory muscle strength, posture assessment, stabilometry, six-minute walking distance (6MWD), and QOL.
RESULTS:
All pulmonary function variables exhibited statistically significant differences between the two groups, except for the DLco. The maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and 6MWD were lower in group B. The maximal mediolateral velocity and the mediolateral displacement were significantly different, while the postural changes and QOL were similar between the groups.
CONCLUSIONS:
In adult individuals with asthma, the pulmonary function is associated with balance control in the mediolateral direction but does not influence the postural changes or QOL.
Asthma; Respiratory Function Tests; Posture; Postural Balance
INTRODUCTION
Asthma is a chronic inflammatory disease of the airways that involves many cells and cellular
elements (11. GINA. Global initiative for Asthma Report. 1995. Workshop Report Revision 2006.
Update 2007. Available from: www.ginasthma.org; 2011.
www.ginasthma.org...
). Chronic inflammation, which is also present in
patients with a recent episode of and mild forms of asthma (including the asymptomatic types), is
associated with airway hyper-responsiveness. This condition causes recurrent episodes of wheezing,
dyspnea, chest oppression, and coughing, particularly during the night or early in the morning
(22. Riley S, Wallace J, Nair P. Proximity to major roadways is a risk factor for
airway hyper-responsiveness in adults. Can Respir J. 2012;19(2):89-95.). The World Health Organization estimates that 235 million
people suffer from asthma (33. WHO Website. World Health Organization. Chronic Respiratory Diseases. Available
from: www.who.int/respiratory/asthma/en/; 2012.
www.who.int/respiratory/asthma/en/...
).
Patients with asthma and other chronic respiratory diseases tend to develop changes in posture
and balance (44. Smith MD, Chang AT, Seale HE, Walsh JR, Hodges PW. Balance is impaired in people
with chronic obstructive pulmonary disease. Gait Posture. 2010;31(4):456-60,
http://dx.doi.org/10.1016/j.gaitpost.2010.01.022.
http://dx.doi.org/10.1016/j.gaitpost.201...
,55. Roig M, Eng JJ, Road JD, Reid WD. Falls in patients with chronic obstructive
pulmonary disease: a call for further research. Respir Med. 2009;103(9):1257-69,
http://dx.doi.org/10.1016/j.rmed.2009.03.022.
http://dx.doi.org/10.1016/j.rmed.2009.03...
).
Asthmatic individuals exhibit an excessive recruitment of inspiratory accessory and expiratory
muscles in response to the airflow obstruction that leads to maladaptive hypertrophy (55. Roig M, Eng JJ, Road JD, Reid WD. Falls in patients with chronic obstructive
pulmonary disease: a call for further research. Respir Med. 2009;103(9):1257-69,
http://dx.doi.org/10.1016/j.rmed.2009.03.022.
http://dx.doi.org/10.1016/j.rmed.2009.03...
,66. Lunardi AC, Marques da Silva CC, Rodrigues Mendes FA, Marques AP, Stelmach R,
Fernandes Carvalho CR. Musculoskeletal dysfunction and pain in adults with asthma. J Asthma.
2011;48(1):105-10, http://dx.doi.org/10.3109/02770903.2010.520229.
http://dx.doi.org/10.3109/02770903.2010....
). Under tension, these
muscles shorten and lose flexibility, causing a reduction in their length and strength (77. Stewart A. More muscle in asthma, but where did it come from?
Am J Respir Crit Care Med. 2012;185(10):1035-7,
http://dx.doi.org/10.1164/rccm.201203-0457ED.
http://dx.doi.org/10.1164/rccm.201203-04...
). The biomechanics of the thoracic cage do not operate in
isolation but are integrated with the body's global mechanics. Therefore, any change in the
thoracic cage may cause repercussions in the overall biomechanics of the body (88. Dalleau G, Leroyer P, Beaulieu M, Verkindt C, Rivard CH, Allard P. Pelvis
morphology, trunk posture and standing imbalance and their relations to the Cobb angle in moderate
and severe untreated AIS. PLoS One. 2012;7(7):e36755,
http://dx.doi.org/10.1371/journal.pone.0036755.
http://dx.doi.org/10.1371/journal.pone.0...
9. Brasiliense LB, Lazaro BC, Reyes PM, Dogan S, Theodore N, Crawford NR.
Biomechanical contribution of the rib cage to thoracic stability. Spine. 2011;36(26):E1686-93,
http://dx.doi.org/10.1097/BRS.0b013e318219ce84.
http://dx.doi.org/10.1097/BRS.0b013e3182...
-1010. Gabrielli F, Subit D, Ogam E, Guillemain P, Kent RW, Masson C. Time-frequency
analysis to detect bone fracture in impact biomechanics: application to the thorax. Med Eng Phys.
2009;31(8):952-8, http://dx.doi.org/10.1016/j.medengphy.2009.05.007.
http://dx.doi.org/10.1016/j.medengphy.20...
).
Some evidence indicates that patients with several lung disorders exhibit significant deficits in
postural balance, for which the physiopathological basis appears to be multifactorial (44. Smith MD, Chang AT, Seale HE, Walsh JR, Hodges PW. Balance is impaired in people
with chronic obstructive pulmonary disease. Gait Posture. 2010;31(4):456-60,
http://dx.doi.org/10.1016/j.gaitpost.2010.01.022.
http://dx.doi.org/10.1016/j.gaitpost.201...
). Weakness of the limbs, changes in balance, nutritional
depletion, malnutrition, depression, cognitive deficits, and the use of medications might be
considered risk factors for falls among patients with respiratory diseases, such as chronic
obstructive pulmonary disease (COPD) (55. Roig M, Eng JJ, Road JD, Reid WD. Falls in patients with chronic obstructive
pulmonary disease: a call for further research. Respir Med. 2009;103(9):1257-69,
http://dx.doi.org/10.1016/j.rmed.2009.03.022.
http://dx.doi.org/10.1016/j.rmed.2009.03...
,1111. Ozalevle S, Ilgin D, Narin S, Akkoclu A. Association between disease-related
factors and balance and falls among the elderly with COPD: a cross-sectional study. Aging Clin Exp
Res. 2011;23(5-6):372-7.,1212. Hellström K, Vahlberg B, Urell C, Emtner M. Fear of falling, fall-related
self-efficacy, anxiety and depression in individuals with chronic obstructive pulmonary disease.
Clin Rehabil. 2009;23(12):1136-44, http://dx.doi.org/10.1177/0269215509342329.
http://dx.doi.org/10.1177/02692155093423...
). Nevertheless, there is not yet
sufficient evidence to associate pulmonary function impairment with postural balance and body
posture changes in patients with asthma.
Asthma may cause systemic repercussions due to its severity and the effects of treatment. Therefore, we hypothesized that factors such as posture, balance, functional capacity, and quality of life (QOL) are altered in patients with poor pulmonary function. Consequently, the aim of this study was to compare these factors between two groups of asthmatic individuals who were grouped based on their pulmonary function levels.
METHODS
The present investigation was a cross-sectional study conducted with patients recruited at the
Newton Bethlem Medical Care Center in Rio de Janeiro, Brazil. Individuals diagnosed with asthma who
were 18 to 50 years of age were included. Individuals who were using psychotropic medications; had a
diagnosis or history of cardiovascular disease, respiratory comorbidities, or vestibular disorders;
were smokers or ex-smokers; had a respiratory infection within the previous three months; or had any
type of physical disability impairing locomotion were excluded from this study. Individuals older
than 50 years were excluded due to the fall risk inherent to this population (44. Smith MD, Chang AT, Seale HE, Walsh JR, Hodges PW. Balance is impaired in people
with chronic obstructive pulmonary disease. Gait Posture. 2010;31(4):456-60,
http://dx.doi.org/10.1016/j.gaitpost.2010.01.022.
http://dx.doi.org/10.1016/j.gaitpost.201...
,55. Roig M, Eng JJ, Road JD, Reid WD. Falls in patients with chronic obstructive
pulmonary disease: a call for further research. Respir Med. 2009;103(9):1257-69,
http://dx.doi.org/10.1016/j.rmed.2009.03.022.
http://dx.doi.org/10.1016/j.rmed.2009.03...
,1111. Ozalevle S, Ilgin D, Narin S, Akkoclu A. Association between disease-related
factors and balance and falls among the elderly with COPD: a cross-sectional study. Aging Clin Exp
Res. 2011;23(5-6):372-7.,1212. Hellström K, Vahlberg B, Urell C, Emtner M. Fear of falling, fall-related
self-efficacy, anxiety and depression in individuals with chronic obstructive pulmonary disease.
Clin Rehabil. 2009;23(12):1136-44, http://dx.doi.org/10.1177/0269215509342329.
http://dx.doi.org/10.1177/02692155093423...
). The study was approved by the Research Ethics
Committee of the Augusto Motta University, Rio de Janeiro (number 0012.0.307.228-11). All the
participants signed an informed consent form.
Subjects
Between September 2011 and August 2012, 66 patients were assessed (Figure 1). From these individuals, 16 were excluded, including six who did not complete
the tests, two who were unable to perform pulmonary function testing, three who exhibited an
associated restrictive syndrome, four who withdrew from the study, and one who died due to acute
myocardial infarction. The sample population was divided into two groups according to the median
value of the forced expiratory volume in one second (FEV1) as follows: group A
= FEV1 >74% predicted; group B = FEV1
<74% predicted. The FEV1 was chosen because it is the most widely used index,
compared with other lung function parameters, for monitoring adults with asthma (11. GINA. Global initiative for Asthma Report. 1995. Workshop Report Revision 2006.
Update 2007. Available from: www.ginasthma.org; 2011.
www.ginasthma.org...
). Its measurement is easily obtainable, highly reproducible, and
widely performed across the world (1313. Pride NB. Testes of forced expiration and inspiration. Clin Chest Med.
2001;22(4):599-622, http://dx.doi.org/10.1016/S0272-5231(05)70055-1.
http://dx.doi.org/10.1016/S0272-5231(05)...
).
Analysis of pulmonary function and functional capacity
Spirometry, whole-body plethysmography, respiratory muscle strength, and the diffusing capacity
for carbon monoxide (DLco) were measured using the computerized Collins Plus Pulmonary Function
Testing Systems (Warren E. Collins, Inc., Braintree, MA, USA) at the Laboratory of Pulmonary
Function of the State University of Rio de Janeiro. All tests followed the standards of the American
Thoracic Society (1414. Miller MR, Hankinson J, Brusasco V. ATS/ERS Task Force. Standardization of
spirometry. Eur Respir J. 2005:26(2);319-38,
http://dx.doi.org/10.1183/09031936.05.00034805.
http://dx.doi.org/10.1183/09031936.05.00...
). Pereira's (1515. Pereira CAC, Sato T, Rodrigues SC. New reference values for forced spirometry in
white adults in Brazil. J Bras Pneumol. 2007;33(4):397-406.) and Neder's (1616. Neder JA, Andreoni S, Castelo-Filho A, Nery LE. Reference values for lung
function tests. I. Static volumes. Braz J Med Biol Res.
1999;32(6):703-17.
17. Neder JA, Andreoni S, Lerario MC, Nery LE. Reference values for lung function
tests. II. Maximal respiratory pressures and voluntary ventilation. Braz J Med Biol Res.
1999;32(6):719-27.-1818. Neder JA, Andreoni S, Peres C, Nery LE. Reference values for lung function
tests. III. Carbon monoxide diffusing capacity (transfer factor). Braz J Med Biol Res.
1999;32(6):729-37, http://dx.doi.org/10.1590/S0100-879X1999000600008.
http://dx.doi.org/10.1590/S0100-879X1999...
) equations were used to interpret the functional parameters. The
six-minute walking test (6MWT) was performed at the same location along a three-meter corridor,
according to the ATS recommendations. The predicted six-minute walking distance (6MWD) was estimated
for all the patients, using the equations from Gibbons et al. (1919. Gibbons WJ, Fruchter N, Sloan S, Levy RD. Reference values for a multiple
repetition 6- minute walk test in healthy adults older than 20 years. J Cardiopulm Rehabil.
2001;21(2):87-93, http://dx.doi.org/10.1097/00008483-200103000-00005.
http://dx.doi.org/10.1097/00008483-20010...
).
Postural assessment
The body posture analysis was performed at the Human Movement Analysis Laboratory - Augusto Motta
University, via photogrammetry using the postural assessment software (PAS, FAPESP Incubator, SP,
Brazil) (2020. Ferreira EAG, Duarte M, Maldonado EP, Burke TN, Marques AP. Postural assessment
software (PAS/SAPO): validation and reliability. Clinics. 2010;65(7):675-81,
http://dx.doi.org/10.1590/S1807-59322010000700005.
http://dx.doi.org/10.1590/S1807-59322010...
). For the acquisition of photographs, the
coordinates of the anatomical points marked with passive markers (specifically, Styrofoam balls held
with double-sided tape) were used. For all participants, four photographs were acquired in the
anterior, posterior, and lateral (right and left) views after the anatomical points were located
(Figure 2). The anatomical points were chosen based on
previous studies that, using the same or a similar method, found an association between pulmonary
function and posture in patients with chronic pulmonary diseases (2121. Pachioni CAS, Ferrante JA, Panissa TSD, Ferreira DMA, Ramos D, Moreira GL, et
al. Postural assessment in patients with chronic obstructive pulmonary disease. Fisioter Pesq.
2011;18(4):341-5.,2222. Penafortes JT, Guimarães FS, Moço VJ, Almeida VP, Dias RF, Lopes AJ.
Association among posture, lung function and functional capacity in cystic fibrosis. Rev Port
Pneumol. 2013;19(1):1-6, http://dx.doi.org/10.1016/j.rppneu.2012.07.001.
http://dx.doi.org/10.1016/j.rppneu.2012....
). The patients were placed in an orthostatic
position on a sheet of paper on which their feet had been previously outlined, and they were
instructed to adopt a comfortable position. A plumb line with two Styrofoam balls placed 1.20 meters
apart was placed next to the patients and was later used to calibrate the photographs in the
software. The camera was placed 163 cm above the floor and 3.0 meters from the patients. After each
photograph, the sheet of paper was rotated 90°, and the patients were repositioned. The
photographs were transferred to a compatible microcomputer and analyzed.
Anatomical points that were evaluated by the PAS protocol: (11. GINA. Global initiative for Asthma Report. 1995. Workshop Report Revision 2006. Update 2007. Available from: www.ginasthma.org; 2011.
www.ginasthma.org... ) tragus (anterior view); (22. Riley S, Wallace J, Nair P. Proximity to major roadways is a risk factor for airway hyper-responsiveness in adults. Can Respir J. 2012;19(2):89-95.) acromion (anterior view); (33. WHO Website. World Health Organization. Chronic Respiratory Diseases. Available from: www.who.int/respiratory/asthma/en/; 2012.
www.who.int/respiratory/asthma/en/... ) anterior-superior iliac spine (ASIS); (44. Smith MD, Chang AT, Seale HE, Walsh JR, Hodges PW. Balance is impaired in people with chronic obstructive pulmonary disease. Gait Posture. 2010;31(4):456-60, http://dx.doi.org/10.1016/j.gaitpost.2010.01.022.
http://dx.doi.org/10.1016/j.gaitpost.201... ) spinal processes of the third thoracic (T3) vertebrae; (55. Roig M, Eng JJ, Road JD, Reid WD. Falls in patients with chronic obstructive pulmonary disease: a call for further research. Respir Med. 2009;103(9):1257-69, http://dx.doi.org/10.1016/j.rmed.2009.03.022.
http://dx.doi.org/10.1016/j.rmed.2009.03... ) scapula (inferior angle); (66. Lunardi AC, Marques da Silva CC, Rodrigues Mendes FA, Marques AP, Stelmach R, Fernandes Carvalho CR. Musculoskeletal dysfunction and pain in adults with asthma. J Asthma. 2011;48(1):105-10, http://dx.doi.org/10.3109/02770903.2010.520229.
http://dx.doi.org/10.3109/02770903.2010.... ) greater trochanter; (77. Stewart A. More muscle in asthma, but where did it come from? Am J Respir Crit Care Med. 2012;185(10):1035-7, http://dx.doi.org/10.1164/rccm.201203-0457ED.
http://dx.doi.org/10.1164/rccm.201203-04... ) tragus (lateral view); (88. Dalleau G, Leroyer P, Beaulieu M, Verkindt C, Rivard CH, Allard P. Pelvis morphology, trunk posture and standing imbalance and their relations to the Cobb angle in moderate and severe untreated AIS. PLoS One. 2012;7(7):e36755, http://dx.doi.org/10.1371/journal.pone.0036755.
http://dx.doi.org/10.1371/journal.pone.0... ) spinal processes of the seventh cervical (C7) vertebrae; (99. Brasiliense LB, Lazaro BC, Reyes PM, Dogan S, Theodore N, Crawford NR. Biomechanical contribution of the rib cage to thoracic stability. Spine. 2011;36(26):E1686-93, http://dx.doi.org/10.1097/BRS.0b013e318219ce84.
http://dx.doi.org/10.1097/BRS.0b013e3182... ) acromion (lateral view); (1010. Gabrielli F, Subit D, Ogam E, Guillemain P, Kent RW, Masson C. Time-frequency analysis to detect bone fracture in impact biomechanics: application to the thorax. Med Eng Phys. 2009;31(8):952-8, http://dx.doi.org/10.1016/j.medengphy.2009.05.007.
http://dx.doi.org/10.1016/j.medengphy.20... ) posterior-superior iliac spine; (1111. Ozalevle S, Ilgin D, Narin S, Akkoclu A. Association between disease-related factors and balance and falls among the elderly with COPD: a cross-sectional study. Aging Clin Exp Res. 2011;23(5-6):372-7.) knee (articular line); and (1212. Hellström K, Vahlberg B, Urell C, Emtner M. Fear of falling, fall-related self-efficacy, anxiety and depression in individuals with chronic obstructive pulmonary disease. Clin Rehabil. 2009;23(12):1136-44, http://dx.doi.org/10.1177/0269215509342329.
http://dx.doi.org/10.1177/02692155093423... ) lateral malleoli.
Before analysis, the photographs were calibrated based on the two plumb line Styrofoam balls. The anatomical points marked on the patients were also marked on the photographs using the mouse, according to the software protocol. A report was generated at the end of each assessment and listed the results of the following parameters: (a) the anterior view: head - horizontal alignment, angle between the acromion and the anterior-superior iliac spine (ASIS), and ASIS - horizontal alignment; (b) the posterior view: scapula - third thoracic (T3) vertebrae horizontal asymmetry; and (c) the right and left side views: head - horizontal and vertical alignment, trunk - vertical alignment, body - vertical alignment, pelvis - horizontal alignment, knee angle, and ankle angle.
Analysis of static postural balance
The participants performed stabilometry on a force platform (AccuSway Plus, AMTI, Watertown, MA,
USA), and the data collected were analyzed using the SuiteEBG software, version 1.0 (PGSM, Paris,
France). The tests were performed under an open eye, open base condition. The participants were
requested to maintain the static posture while watching a target on a wall for 30 seconds at a
sampling frequency of 100 Hz. The position of the feet had been previously outlined on the platform
base with chalk, and the participants were requested to keep their feet turned forward and apart
from each other up to the margins of the platform. The representative value for each postural
balance variable was computed as the average of three trials (2323. Cunha AGJ, Nunes MPT, Ramos RT, Carvalho-Pinto RM, Boffino CC, Martins FC, et
al. Balance disturbances in asthmatic patients. J Asthma. 2013;50(3):282-6,
http://dx.doi.org/10.3109/02770903.2012.750668.
http://dx.doi.org/10.3109/02770903.2012....
). The following stabilometric variables were calculated: mediolateral standard deviation
(X SD), anteroposterior standard deviation (Y SD), mediolateral amplitude (X range), anteroposterior
range (Y range), elliptical area (assessed by a principal component analysis), average velocity,
maximal mediolateral velocity (Vx), and maximal anteroposterior velocity (Vy) (2424. Martinelli AR, Purga MO, Mantovani AM, Camargo MR, Rosell AA, Prado CE, et al.
Analysis of lower limb alignment in overweight children. Rev Bras Cineantropom Desempenho Hum.
2011;13(2):124-30.
25. Saad KR, Colombo AS, Ribeiro AP, João SM. Reliability of photogrammetry in
the evaluation of the postural aspects of individuals with structural scoliosis. J Bodyw Mov
Ther. 2012;16(2):210-6, http://dx.doi.org/10.1016/j.jbmt.2011.03.005.
http://dx.doi.org/10.1016/j.jbmt.2011.03...
-2626. Berthonnaud E, Hilmi R, Dimnet J. Personalized models of bones based on
radiographic photogrammetry. Surg Radiol Anat. 2009;31(6):461-70,
http://dx.doi.org/10.1007/s00276-009-0468-0.
http://dx.doi.org/10.1007/s00276-009-046...
).
Analysis of the QOL
The QOL was assessed by the Asthma Questionnaire of Life Quality (AQLQ), which comprised 32
questions corresponding to the following four domains: activity limitation, symptoms, emotional
function, and environmental stimuli. The score of each response varied from one (minimum score;
severely impaired) to seven (maximum score; not impaired) points. The overall score was the mean of
all 32 responses, and the individual domain scores were the means of the items in those domains. As
the minimal score was one and the maximal score was seven, a higher overall score indicated a higher
QOL. An increase of 0.5 point between assessments was considered clinically relevant (2727. Mancuso CA, Peterson MG, Gaeta TJ, Fernández JL, Birkhahn RH. Time to
seeking emergency department care for asthma: self-management, clinical features at presentation,
and hospitalization. J Asthma. 2012;49(3):275-81,
http://dx.doi.org/10.3109/02770903.2012.661011.
http://dx.doi.org/10.3109/02770903.2012....
28. Ozgen Alpaydin A, Yorgancioglu A, Yilmaz O, Bora M, Göktalay T, Celik P, et
al. Validity and reliability of “Asthma Quality of Life Questionnaire”
in a sample of Turkish adult asthmatic patients. Tuberk Toraks. 2011;59(4):321-7,
http://dx.doi.org/10.5578/tt.2447.
http://dx.doi.org/10.5578/tt.2447...
-2929. Chhabra SK, Chhabra P. Gender differences in perception of dyspnea, assessment
of control, and quality of life in asthma. J Asthma. 2011;48(6):609-15,
http://dx.doi.org/10.3109/02770903.2011.587577.
http://dx.doi.org/10.3109/02770903.2011....
).
Statistical analysis
To estimate the sample size, a pilot study was conducted using a protocol identical to that described above in a group of 20 subjects. Based on these preliminary results, the MedCalcH 8.2 software (Medicalc Software Mariakerke, Belgium) was used to calculate the sample size based on the median values of FEV1, assuming type I and type II errors of 1%. The minimal calculated value for this study required 25 individuals for each group.
The data are presented as the median and interquartile intervals (25th and 75th percentiles) or as a frequency (percentage). As the distribution of the variables was non-normal by the Shapiro-Wilk test, the Mann-Whitney test was used to perform the comparisons. A multifactorial variance analysis was performed to investigate the association between the pulmonary function, functional capacity, posture, balance, and possible confounders. This model was designed to analyze the FEV1 as the dependent variable, with covariates of age, duration of symptoms, use of oral corticosteroids (yes/no), use of inhaled corticosteroids (yes/no), maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), DLco, 6MWD, stabilometric parameters, and PAS measurements. The analysis was performed using the SigmaStat software for Windows, version 3.5 (Systat Software, Inc., Chicago, IL, USA). Statistical significance was established as p<0.05.
RESULTS
The general characteristics, pulmonary function testing, functional capacity, and QOL results for
both groups are described in Table 1). Most patients
were female (72%), and the median ages were 31 years for group A and 33 years for group B. All the
pulmonary function variables (spirometry, whole-body plethysmography, and respiratory muscle
strength) exhibited statistically significant differences between the two groups, except for the
DLco (p = 0.06). The median of the 6MWD was 625 meters (566.5-687
meters) in group A, which was significantly higher than the median of group B, 577 meters (505-607.2
meters) (p = 0.05). The medians of the percentages predicted by the
equations from Gibbons et al. (1919. Gibbons WJ, Fruchter N, Sloan S, Levy RD. Reference values for a multiple
repetition 6- minute walk test in healthy adults older than 20 years. J Cardiopulm Rehabil.
2001;21(2):87-93, http://dx.doi.org/10.1097/00008483-200103000-00005.
http://dx.doi.org/10.1097/00008483-20010...
) for those distances were
86.6% and 80.5% for groups A and B, respectively (p = 0.03).
The stabilometric data are described in Table 2. The variables related to the amplitude of the mediolateral sway (X SD, X range) and the velocity of displacement of the center of pressure (CoP) along the mediolateral axis (Vx) exhibited statistical significance between the groups (p<0.001, p = 0.04, and p<0.001, respectively). Table 3 describes the postural analysis values of the entire sample and those for groups A and B individually. No variable exhibited a significant difference between the groups (p>0.05 for all variables).
All variables were assessed in a multifactorial variance model (Table 4). The covariates X SD, Vx, and MIP were significantly associated with the FEV1.
DISCUSSION
The main findings of the present study were as follows: (a) there were significant differences in the variables related to balance and functional capacity between the two groups of asthmatic individuals who were divided according to the FEV1, and (b) the posture and QOL parameters did not exhibit a significant difference between the groups. Until the present, no study appears to have focused on these topics in an integrated manner.
Most of the participants were women, which is in agreement with the literature reports of a
higher prevalence of asthma among adult females (3030. Hakola R, Kauppi P, Leino T, Ojajärvi A, Pentti J, Oksanen T, et al.
Persistent asthma, comorbid conditions and the risk of work disability: a prospective cohort study.
Allergy. 2011;66(12):1598-603, http://dx.doi.org/10.1111/j.1398-9995.2011.02729.x.
http://dx.doi.org/10.1111/j.1398-9995.20...
,3131. Agache IO, Ciobanu CM, Paul G, Rogozea L. Dysfunctional breathing phenotype in
adults with asthma: incidence and risk factors. Clin Transl Allergy. 2012;2(1):18,
http://dx.doi.org/10.1186/2045-7022-2-18.
http://dx.doi.org/10.1186/2045-7022-2-18...
). The median FEV1 value [74% (53-87%)]
indicates that the present study assessed a homogeneous sample population corresponding to the
moderate persistent stage based on the older Global Initiative for Asthma (GINA) classification
(11. GINA. Global initiative for Asthma Report. 1995. Workshop Report Revision 2006.
Update 2007. Available from: www.ginasthma.org; 2011.
www.ginasthma.org...
). Because the FEV1 was used to divide the
groups, a difference was observed for all pulmonary function parameters, except for the DLco
(p = 0.06). Notably, the mechanisms underlying the FEV1
and DLco are different, as the former assesses lung mechanics, and the latter assesses the transfer
of gases from the alveoli to the red blood cells (3232. Gershon AS, Victor JC, Guan J, Aaron SD, To T. Pulmonary function testing in the
diagnosis of asthma: a population study. Chest. 2012;141(5):1190-6,
http://dx.doi.org/10.1378/chest.11-0831.
http://dx.doi.org/10.1378/chest.11-0831...
,3333. Loniţă D. Pulmonary function tests in bronchial asthma.
Pneumologia. 2008;57(2):70-4.).
The patients in group B presented with lower respiratory muscle strength. This result is in agreement with the premise that the inspiratory muscles of chronic asthmatic patients are shortened due to hyperinflation, reducing their efficacy (3434. Gomieiro LT, Nascimento A, Tanno LK, Agondi R, Kalil J, Giavina-Bianchi P. Respiratory exercise program for elderly individuals with asthma. Clinics. 2011;66(7):116-39.,3535. Oliveira CM, Lanza FC, Solé D. Respiratory muscle strength in children and adolescents with asthma: similar to that of healthy subjects? J Bras Pneumol. 2012;38(3):308-14.). A Brazilian study assessed the effects of muscle stretching on the MIP and MEP values and found an improvement in respiratory muscle strength following sessions of global posture re-education among healthy individuals (3636. Moreno MA, Catai AM, Teodori RM, Borges BL, Cesar MC, Silva E. Effect of a muscle stretching program using the Global Postural Reeducation method on respiratory muscle strength and thoracoabdominal mobility of sedentary young males. J Bras Pneumol. 2007;33(6):679-86.). As there is no evidence indicating whether the same results might be achieved in asthmatic patients with different degrees of airflow obstruction, this topic is an area for future research.
Several QOL questionnaires have revealed that the results might help to establish the severity of
asthma and that modification of the results might correlate with the clinical status of patients
(3737. Apfelbacher C, Weiß M, Saur J, Smith H, Loerbroks A. Patients' views
on asthma-specific quality of life questionnaires: qualitative interview study in Germany.
J Asthma. 2012;49(8):875-83, http://dx.doi.org/10.3109/02770903.2012.713427.
http://dx.doi.org/10.3109/02770903.2012....
,3838. Korn S, Both J, Jung M, Hübner M, Taube C, Buhl R. Prospective evaluation
of current asthma control using ACQ and ACT compared with GINA criteria. Ann Allergy Asthma Immunol.
2011;107(6):474-9, http://dx.doi.org/10.1016/j.anai.2011.09.001.
http://dx.doi.org/10.1016/j.anai.2011.09...
). A study has
demonstrated that, in adults with asthma, the QOL is closely related to the frequency of symptoms
and the level of pulmonary function (3838. Korn S, Both J, Jung M, Hübner M, Taube C, Buhl R. Prospective evaluation
of current asthma control using ACQ and ACT compared with GINA criteria. Ann Allergy Asthma Immunol.
2011;107(6):474-9, http://dx.doi.org/10.1016/j.anai.2011.09.001.
http://dx.doi.org/10.1016/j.anai.2011.09...
). In our
investigation, the two groups did not exhibit a significant difference in the median values of the
AQLQ. The socioeconomic conditions of the investigated sample might have influenced this result.
Several patients reported an inability to discontinue their activities (particularly paid work)
despite exhibiting symptoms and thus did not rate their activity as limited by the disease.
The assessment of patients' functional capacity is important for evaluating the response to
interventions and for prescribing physical training protocols (3939. Jenkins S, Cecins NM. Six-minute walk test in pulmonary rehabilitation: do all
patients need a practice test? Respirology. 2010;15(8):1192-6,
http://dx.doi.org/10.1111/j.1440-1843.2010.01841.x.
http://dx.doi.org/10.1111/j.1440-1843.20...
). In our study, the 6MWT proved to be a reliable method of assessing the functional
capacity of asthmatic individuals. The test was easily understood, tolerated, and accepted by the
participants. Group A exhibited a greater predicted 6MWD than group B did (86.6%
vs. 80.5%, respectively; p<0.05), which denotes a greater
functional capacity defined by the patients' ability to perform everyday activities. In a study
conducted with adult women who were classified with mild to moderate asthma
(FEV1 = 72.9±19.3%), the average 6MWD was lower than in group B of our
study (524 meters vs. 575 meters, respectively) and was even lower when compared to
group A (524 meters vs. 625 meters, respectively) (4040. Silva TLPS, Sampaio LMM, Borghi-Silva A, Kunikoshita LN, Costa D. Comparison of
corridor and treadmill six- minutes walk test in asthmatic women. Fisioterapia em Movimento.
2007;20(2):137-44.). The same result was obtained in a comparison of another study of sedentary individuals
and in groups A and B of our investigation (544 meters vs. 575 meters and 544
meters vs. 625 meters, respectively) (4141. Fernandes PM, Pereira NH, Santos ACBC, Soares MESM. Six-minute walk test:
evaluation on the functional capacity of sedentary individuals. Rev Bras Cardiol.
2012;25(3):185-91.);
however, the sample from the former study consisted of young adults (20-30 years of age) and used a
different reference equation than the one used in our investigation.
The alignment of the static posture is considered adequate when the overload on the joints,
ligaments, and bones that are required to support the body weight is minimal (88. Dalleau G, Leroyer P, Beaulieu M, Verkindt C, Rivard CH, Allard P. Pelvis
morphology, trunk posture and standing imbalance and their relations to the Cobb angle in moderate
and severe untreated AIS. PLoS One. 2012;7(7):e36755,
http://dx.doi.org/10.1371/journal.pone.0036755.
http://dx.doi.org/10.1371/journal.pone.0...
,1111. Ozalevle S, Ilgin D, Narin S, Akkoclu A. Association between disease-related
factors and balance and falls among the elderly with COPD: a cross-sectional study. Aging Clin Exp
Res. 2011;23(5-6):372-7.). Photogrammetry has been increasingly
used in several Brazilian studies, and the PAS is one of the most widely used postural analysis
systems because it exhibits satisfactory intra- and inter-examiner reliabilities (2424. Martinelli AR, Purga MO, Mantovani AM, Camargo MR, Rosell AA, Prado CE, et al.
Analysis of lower limb alignment in overweight children. Rev Bras Cineantropom Desempenho Hum.
2011;13(2):124-30.,4242. Yi LC, Jardim JR, Inoue DP, Pignatari SS. The relationship between excursion of
the diaphragm and curvatures of the spinal column in mouth breathing children. J Pediatr (Rio
J). 2008;84(2):171-7.). In the present
study, we did not find significant differences between the groups with respect to body posture
variables. We did not find any literature reports of the normal values of these variables for
comparison. Robles-Ribeiro et al. (4343. Robles-Ribeiro P, Ribeiro M, Lianza S. Relationship between peak expiratory flow
rate and shoulders posture in healthy individuals and moderate to severe asthmatic patients.
J Asthma. 2005;42(9):783-6, http://dx.doi.org/10.1080/02770900500308411.
http://dx.doi.org/10.1080/02770900500308...
) reported that adult
patients with mild to severe asthma exhibited several postural changes, including protracted
shoulders. However, the quantitative measures related to this change, specifically scapula and T3
asymmetry, do not allow for confirming that observation. Danis et al. (4444. Danis CG, Krebs DE, Gill-Body KM, Sahrmann S. Relationship between standing
posture and stability. Phys Ther. 1998;78(5):502-46.) found a weak correlation between posture and stability (r<0.30;
p≤0.05) in patients with vestibular dysfunction and in healthy individuals.
The authors suggested that major postural changes may correlate with stability, which was not
observed for either group in our study.
The understanding of posture includes the idea of postural control. The alignment of the body segments and postural alterations might affect the location of the gravity center, thus affecting the control of body stability (4444. Danis CG, Krebs DE, Gill-Body KM, Sahrmann S. Relationship between standing posture and stability. Phys Ther. 1998;78(5):502-46.). Neither group in our study exhibited postural changes (p>0.05), which might be explained by the ability of the human body to adapt to various conditions.
Stability is achieved through the generation of moments of force on the body joints to neutralize
the effect of gravity and any other perturbation. This continuous and dynamic process maintains a
given posture over time. Therefore, the integration of somatosensory and vestibular input is
necessary to ensure adequate postural control (2424. Martinelli AR, Purga MO, Mantovani AM, Camargo MR, Rosell AA, Prado CE, et al.
Analysis of lower limb alignment in overweight children. Rev Bras Cineantropom Desempenho Hum.
2011;13(2):124-30.). While the
anteroposterior balance is maintained by the ankle torque, the mediolateral balance is maintained by
the hip and trunk torque. As observed in patients with COPD, in the present study, the degree of
hyperinflation in the group with more severe asthma might also contribute to the increased activity
of the trunk muscles, with a consequent increase in their rigidity. These phenomena might reduce the
contribution of the trunk movements and the force moments for balance control (44. Smith MD, Chang AT, Seale HE, Walsh JR, Hodges PW. Balance is impaired in people
with chronic obstructive pulmonary disease. Gait Posture. 2010;31(4):456-60,
http://dx.doi.org/10.1016/j.gaitpost.2010.01.022.
http://dx.doi.org/10.1016/j.gaitpost.201...
,55. Roig M, Eng JJ, Road JD, Reid WD. Falls in patients with chronic obstructive
pulmonary disease: a call for further research. Respir Med. 2009;103(9):1257-69,
http://dx.doi.org/10.1016/j.rmed.2009.03.022.
http://dx.doi.org/10.1016/j.rmed.2009.03...
). Interestingly, Cunha et al. (2323. Cunha AGJ, Nunes MPT, Ramos RT, Carvalho-Pinto RM, Boffino CC, Martins FC, et
al. Balance disturbances in asthmatic patients. J Asthma. 2013;50(3):282-6,
http://dx.doi.org/10.3109/02770903.2012.750668.
http://dx.doi.org/10.3109/02770903.2012....
) also demonstrated a higher area of CoP displacement in adults
with asthma using a force platform.
We also investigated whether the clinical data, functional capacity, posture, and balance could
independently predict the pulmonary function. In this investigation, the X SD, Vx, and MIP were
covariates for the FEV1. Mientjes and Frank (4545. Mientjes MI, Frank JS. Balance in chronic low back pain patients compared to
healthy people under various conditions in upright standing. Clin Biomech. 1999;14(10):710-6,
http://dx.doi.org/10.1016/S0268-0033(99)00025-X.
http://dx.doi.org/10.1016/S0268-0033(99)...
)
demonstrated that the modified control of trunk muscles and the reduction in trunk movement were
associated with increased COP displacement, particularly in the mediolateral direction. Thus, it is
reasonable to imagine that these changes may be more marked in adults with severe asthma. The
relationship between the FEV1 and the MIP is also noteworthy. In adults with asthma,
hyperinflation leads to flattening of the diaphragm, causing a mechanical disadvantage and impaired
function of the inspiratory muscles (4646. Weiner P, Suo TJ, Fernandez F, Cherniack RM. Hyperinflation is associated with
reduced strength and efficiency of the respiratory muscles in asthmatic and normal subjects. Chest.
1990;97(Suppl. 3):69S-70S, http://dx.doi.org/10.1378/chest.97.3_Supplement.69S-a.
http://dx.doi.org/10.1378/chest.97.3_Sup...
).
The lack of a control group, the cross-sectional design, and the small sample size are the main
limitations of the present study. Due to the lack of a control group, we cannot definitively
conclude that the changes found are exclusively or mainly caused by the disease severity. In
addition, the present study is a cross-sectional analysis, which makes the establishment of
cause-effect relationships difficult. Thus, longitudinal studies may better clarify these findings.
Furthermore, additional investigations using the 'classification of asthma by level of
control' (11. GINA. Global initiative for Asthma Report. 1995. Workshop Report Revision 2006.
Update 2007. Available from: www.ginasthma.org; 2011.
www.ginasthma.org...
) may provide new insights regarding balance
and its relationship to the QOL.
We conclude that, in adult individuals with asthma, pulmonary function is associated with balance control in the mediolateral direction but does not influence the postural changes or QOL in these patients.
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» http://dx.doi.org/10.3109/02770903.2012.750668 -
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» http://dx.doi.org/10.1378/chest.11-0831 -
33Loniţă D. Pulmonary function tests in bronchial asthma. Pneumologia. 2008;57(2):70-4.
-
34Gomieiro LT, Nascimento A, Tanno LK, Agondi R, Kalil J, Giavina-Bianchi P. Respiratory exercise program for elderly individuals with asthma. Clinics. 2011;66(7):116-39.
-
35Oliveira CM, Lanza FC, Solé D. Respiratory muscle strength in children and adolescents with asthma: similar to that of healthy subjects? J Bras Pneumol. 2012;38(3):308-14.
-
36Moreno MA, Catai AM, Teodori RM, Borges BL, Cesar MC, Silva E. Effect of a muscle stretching program using the Global Postural Reeducation method on respiratory muscle strength and thoracoabdominal mobility of sedentary young males. J Bras Pneumol. 2007;33(6):679-86.
-
37Apfelbacher C, Weiß M, Saur J, Smith H, Loerbroks A. Patients' views on asthma-specific quality of life questionnaires: qualitative interview study in Germany. J Asthma. 2012;49(8):875-83, http://dx.doi.org/10.3109/02770903.2012.713427.
» http://dx.doi.org/10.3109/02770903.2012.713427 -
38Korn S, Both J, Jung M, Hübner M, Taube C, Buhl R. Prospective evaluation of current asthma control using ACQ and ACT compared with GINA criteria. Ann Allergy Asthma Immunol. 2011;107(6):474-9, http://dx.doi.org/10.1016/j.anai.2011.09.001.
» http://dx.doi.org/10.1016/j.anai.2011.09.001 -
39Jenkins S, Cecins NM. Six-minute walk test in pulmonary rehabilitation: do all patients need a practice test? Respirology. 2010;15(8):1192-6, http://dx.doi.org/10.1111/j.1440-1843.2010.01841.x.
» http://dx.doi.org/10.1111/j.1440-1843.2010.01841.x -
40Silva TLPS, Sampaio LMM, Borghi-Silva A, Kunikoshita LN, Costa D. Comparison of corridor and treadmill six- minutes walk test in asthmatic women. Fisioterapia em Movimento. 2007;20(2):137-44.
-
41Fernandes PM, Pereira NH, Santos ACBC, Soares MESM. Six-minute walk test: evaluation on the functional capacity of sedentary individuals. Rev Bras Cardiol. 2012;25(3):185-91.
-
42Yi LC, Jardim JR, Inoue DP, Pignatari SS. The relationship between excursion of the diaphragm and curvatures of the spinal column in mouth breathing children. J Pediatr (Rio J). 2008;84(2):171-7.
-
43Robles-Ribeiro P, Ribeiro M, Lianza S. Relationship between peak expiratory flow rate and shoulders posture in healthy individuals and moderate to severe asthmatic patients. J Asthma. 2005;42(9):783-6, http://dx.doi.org/10.1080/02770900500308411.
» http://dx.doi.org/10.1080/02770900500308411 -
44Danis CG, Krebs DE, Gill-Body KM, Sahrmann S. Relationship between standing posture and stability. Phys Ther. 1998;78(5):502-46.
-
45Mientjes MI, Frank JS. Balance in chronic low back pain patients compared to healthy people under various conditions in upright standing. Clin Biomech. 1999;14(10):710-6, http://dx.doi.org/10.1016/S0268-0033(99)00025-X.
» http://dx.doi.org/10.1016/S0268-0033(99)00025-X -
46Weiner P, Suo TJ, Fernandez F, Cherniack RM. Hyperinflation is associated with reduced strength and efficiency of the respiratory muscles in asthmatic and normal subjects. Chest. 1990;97(Suppl. 3):69S-70S, http://dx.doi.org/10.1378/chest.97.3_Supplement.69S-a.
» http://dx.doi.org/10.1378/chest.97.3_Supplement.69S-a
-
No potential conflict of interest was reported.
Publication Dates
-
Publication in this collection
Nov 2013
History
-
Received
10 Mar 2013 -
Reviewed
9 May 2013 -
Accepted
8 June 2013