Carta al Editor sobre la fiabilidad de las pruebas espirométricas durante las diferentes fases del ciclo menstrual en mujeres sanas.Letter to the Editor about "Reliability of Spirometric Tests during the Different Menstrual Cycle Phases in Healthy Women"peerReviewe

Adsuar Sala, José Carmelo

Maynar Mariño, Marcos Antonio

Pozo Cruz, Borja del

Ramírez Balas, Almudena

Timón Andrada, Rafael

Iranian Journal of Public Health

English

PubMed

Reliability and SRD are important prerequisites for the correct interpreta- tion of spirometric data, which indicate to the clinician whether or not a genuine and real change has occurred. [...]the aim of this study has been to check the reliability of spirometric tests during the menstrual cycle phases and to investi- gate if spirometric variables are modified across the menstrual cycle. On the basis of the percentage of smallest real difference observed in the present study, the size of the relative change (SRD%) should exceed 6.5 % for FEV1, FVC and PEF and 8.3 % for MVV, to indicate a real change for a single individual. [...]these measurements could be used to detect real changes for a single individual following an intervention program, re- gardless of the menstrual cycle phase

Timon, Rafael

Ramirez-Balas, Almudena

Adsuar, Jose C.

del Pozo-Cruz, Borja

Maynar, Marcos

ACU Research Bank

Reliability of spirometric tests during the different menstrual cycle phases in healthy women

Dehesa. Repositorio Institucional de la Universidad de Extremadura

     Iranian J Publ Health, Vol. 43, No.7, Jul 2014, pp. 1009-1010                                                     Letter to the Editor 1009                                                                                                     Available at:    http://ijph.tums.ac.ir   Reliability of Spirometric Tests during the Different Menstrual Cycle Phases in Healthy Women  *Rafael TIMON 1, Almudena RAMIREZ-BALAS 2, Jose C. ADSUAR 1, Borja DEL  POZO-CRUZ 3, Marcos MAYNAR 2  1. Dept. of Physical Education and Sport, Sport Science Faculty, University of Extremadura, Spain 2. Dept. of Physiology, Sport Science Faculty, University of Extremadura, Spain 3. Dept. of Physical Education and Sport, University of Seville, Spain  *Corresponding Author: Email: rtimon@unex.es  (Received 07 May 2014; accepted 27 May 2014)  Dear Editor in Chief  Several studies have suggested that respiratory function is influenced by female sexual hormones. Considering a normal 28-day menstrual cycle, three phases can be distinguished: menstrual, follicular and luteal. Respiratory function is influ-enced by female sexual hormones, which could increase ventilatory response during the luteal phase (1). In contrast, no changes for pulmonary capacities, flows and volumes evaluated by spirometry were found in other investigations (2). These conflicting results may be due to that those studies have not evaluated either, the test reliabil-ity or the smallest real difference (SRD) during the menstrual cycle phases. Reliability and SRD are important prerequisites for the correct interpreta-tion of spirometric data, which indicate to the clinician whether or not a genuine and real change has occurred. Therefore, the aim of this study has been to check the reliability of spirometric tests during the menstrual cycle phases and to investi-gate if spirometric variables are modified across the menstrual cycle. Twenty-three healthy non-smoker women, aged 18 to 35 yr, performed several spirometric tests in three different phases of the menstrual cycle (menstrual, follicular and luteal). In this way, basal body temperature was taken daily upon waking in order to estimate the date of ovulation and to de-fine menstrual cycle phases. Technician provided proper instructions and demonstrated the appropriate techniques before starting the tests. Values of forced expiratory volume at 1 s (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF) and maximum voluntary ventilation (MVV) were tested.  Spirometric values were verified in accordance with the standard of acceptability and criterion of reproducibility recommended by American Thoracic Society and European Respiratory Society (3).  In connection with statistical analysis, the sample size was calculated to achieve a power of 0.95. Data indicated that a minimum of 23 participants were required. Reliability was determined according to the intraclass correlation coefficient (ICC) with 95% confidence intervals across the 3 test sessions. However, more information was needed to analyze how much difference must exist to detect a real variation in a spirometric variable, and therefore standard error of measurement (SEM) and smallest real difference (SRD) were studied as well.  No significant change for flows and volumes were observed during the menstrual cycle (Table 1). All measurements had an intraclass correlation coeffi-cient greater than 0.90. In addition, measurement errors were assessed. Values of SEM (SEM%) ranged from 2.2 % to 3.0 % and values of SRD (SRD%)  ranged from 6.5 % to 8.3 %. Timon et al.: Reliability of Spirometric Tests … Available at:    http://ijph.tums.ac.ir                                                                                                      1010 Table 1: Spirometric variables during the different menstrual cycle phases. Absolute and % predicted values are presented (Mean ± Standard Deviation)  Spirometric variables Menstrual phase Follicular phase Luteal phase P FEV1 (L/s) 3.38 ± 0.37 3.36 ± 0.34 3.35 ± 0.41 0.666 FEV1% 104.2 ± 11 103.0 ± 10 102.6 ± 12 0.666 FVC (L) 3.61 ± 0.46 3.67 ± 0.43 3.60 ± 0.47 0.180 FVC% 100.7 ± 12 102.4 ± 12 99.7 ± 13 0.180 PEF (L/s) 7.81 ± 0.92 7.87 ± 0.99 7.72 ± 1.02 0.552 PEF% 108.0 ± 12 109.2 ± 12 106.5 ± 13 0.552 MVV (L/min) 145.23 ± 21.34 147.57 ± 20.93 144.22 ± 22.58 0.178 MVV% 113.1 ± 15 115.6 ± 14 112.4 ± 16 0.178 No significant differences by ANOVA  Therefore, there is no evidence that respiratory response is modified by sexual hormones in healthy women. Similar results were obtained in other studies that reported no changes in FVC and FEV1during the different menstrual cycle phases (4). In this way, Hayes et al (5) reported that estrogens could have an influence on central nervous activity but not on peripheral reflex (cer-tainly involved in the respiratory mechanism). On the other hand, ICCs for test-retest during the menstrual cycle were excellent for spirometric measurements. To our knowledge, no previous study has reported the reliability of spirometric tests during the menstrual cycle phases in healthy women. However, using only the ICC can give a false impression about the reliability of a measure-ment (6).  Measurement errors should also be small and the method sufficiently sensitive to de-tect real changes. The standard error of measure-ment findings of the present study suggested that the test-retest differences of less 3% for spiromet-ric variables during the different phases of the menstrual cycle should be considered as measure-ment noise. On the basis of the percentage of smallest real difference observed in the present study, the size of the relative change (SRD%) should exceed 6.5 % for FEV1, FVC and PEF  and 8.3 % for MVV, to indicate a real change for a single individual. Therefore, these measurements could be used to detect real changes for a single individual following an intervention program, re-gardless of the menstrual cycle phase.  Acknowledgements  The authors declare that there is no conflict of interests.    References  1. Farha S, Asosingh K, Laskowski D, Hammel J, Dweik RA, Wiedemann HP, Erzurum SC (2009).  Effects of the menstrual cycle on lung function variables in women with asthma. Am J Respir Crit Care Med, 180: 304-10. 2. Matsuo H, Katayama K, Ishida K, Muramatsu T, Miyamura M (2003). Effect of menstrual cycle and gender on ventilatory and heart rate re-sponses at the onset of exercise. Eur J Appl Physiol, 90: 100-08. 3. Miller MR, Hankinson J, Brusasco V, Burgos F, Casaburi R, Coates A, Crapo R, Enright P, Van der Grinten CPM, Gustafsson P, Jensen R, Jonson DC, MacIntyre N, McKay R, Navajas D, Pedersen OF, Pellegrino R, Viegi  G, Wanger J (2005). Standardisation of spirometry. Eur Respir J, 26: 319-38. 4. Da Silva SB, De Sousa Ramalho Viana E, De Sousa MB (2006). Changes in peak expiratory flow and respiratory strength during the menstrual cycle. Respir Physiol Neurobiol, 150: 211-19. 5. Hayes SG, Pino NB, Kaufman MP (2002). Estro-gen attenuates the cardiovascular and ventilatory responses to central command in cats. J Appl Physiol, 92: 1635-41.  6. Lexell JE, Downham DY (2005). How to assess the reliability of measurements in rehabilitation. Am J Phys Med Rehabil, 84: 719-23.  

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Reliability of spirometric tests during the different menstrual cycle phases in healthy women

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