Objective: One of the major issues in the use of spirometry is the evaluation of the values obtained in comparison with standardized reference values. Such reference values should be determined by studying populations similar to the population in which they are intended to be used. Considering the anthropometric differences among races and the effect of regional issues, such as climate and air quality, it is recommended that these standards be set and used regionally. The objective of this study was to measure the spirometric values in residents of the Mazandaran province in Iran, as well as to determine which standardized reference values most closely correlate with the values obtained and to devise predictive equations for the target population. Methods: This was a cross-sectional study of 1,499 volunteers, from whom demographic and anthropometric data were collected. After having been instructed in the correct procedure, each volunteer underwent spirometry. From each volunteer, we obtained three spirometry curves that met the acceptability criteria established by the American Thoracic Society. The test with the highest values of FEV1 and FVC was employed in the analysis. Results: We observed significant correlations between the measured values and the reference values, for both genders. The strongest correlations were with the European Respiratory Society reference values and with the 18-20 year age bracket. The predictive equations devised were based on the regression coefficients obtained and the demographic data collected. Conclusions: Our results show that the European Respiratory Society standard is the most appropriate standard for use in the population studied.

Keywords: Spirometry/statistics  numerical data; Climate effects; Reference values; Iran.

Objective: To establish reference values for the Unsupported Upper Limb EXercise (UULEX) test, which measures peak arm exercise capacity, in healthy adults in Brazil. Methods: This was a cross-sectional study, involving presumably healthy individuals ≥ 30 years of age who completed questionnaires and underwent spirometry. All of the individuals underwent two UULEX tests 30-min apart. The outcome measure was the maximum time (in min) to completion of the test. Results: We included 100 individuals between 30 and 80 years of age. The mean test completion time was 11.99 ± 1.90 min among the women and 12.89 ± 2.15 min among the men (p = 0.03). The test completion time showed statistically significant correlations with age (r = −0.48; p < 0.001), gender (r = 0.28; p = 0.004), body mass index (BMI, r = −0.20; p = 0.05), and height (r = 0.28; p = 0.005). Linear regression analysis showed that the predictors of UULEX completion time were age (p = 0.000), BMI (p = 0.003), and gender (p = 0.019), which collectively explained 30% of the total variability. The mean UULEX completion time was 6% lower for the women than for the men. Conclusions: The present study was able to establish reference values for the UULEX test in healthy adults in Brazil. The values were influenced by age, gender, and BMI.

Keywords: Reference values; Exercise test; Upper extremity

Objective: To determine reference values for the six-minute pegboard and ring test (6PBRT) in healthy adults in Brazil, correlating the results with arm length, circumference of the upper arm/forearm of the dominant arm, and the level of physical activity. Methods: The participants (all volunteers) performed two 6PBRTs, 30 min apart. They were instructed to move as many rings as possible in six minutes. The best test result was selected for data analysis. Results: The sample comprised 104 individuals, all over 30 years of age. Reference values were reported by age bracket. We found that age correlated with 6PBRT results. The number of rings moved was higher in the 30- to 39-year age group than in the > 80-year age group (430.25 ± 77.00 vs. 265.00 ± 65.75), and the difference was significant (p < 0.05). The 6PBRT results showed a weak, positive correlation with the level of physical activity (r = 0.358; p < 0.05) but did not correlate significantly with any other variable studied. Conclusions: In this study, we were able to determine reference values for the 6PBRT in healthy adults in Brazil. There was a correlation between 6PBRT results and age.

Keywords: Upper extremity; Physical endurance; Exercise tolerance; Exercise test.

Objective: To develop regression equations for six-minute walk distance (6MWD) in healthy adults (20-80 years of age) in Brazil. Methods: We included 132 volunteers (66 males) without respiratory disease, cardiac disease, or comorbidities that affect ambulation. The volunteers completed three six-minute walk tests. Prior to and at the end of each test, we obtained SpO2 and maximal HR, as well as the Borg scale scores for sensation of dyspnea and lower limb fatigue. The data included in the final analysis were derived from the test with the greatest 6MWD. Results: The mean 6MWD values were 566 ± 87 m and 538 ± 95 m in males and females, respectively (p = 0.08). The 6MWD was greater in taller individuals and decreased in parallel with increases in age or body index mass (BMI). The best adjusted model was the quadratic model. We derived the following equation (valid for both genders): 6MWD = 511 + stature2 (cm) × 0.0066 − age2 × 0.030 − BMI2 × 0.068. This equation explained 55% of the variance in 6MWD. Conclusions: Reference values explaining a high proportion of the variance were derived by a quadratic regression model in healthy adults (of a wide range of ages) in Brazil. Keywords: Reference values; Exercise test; Walking.

Keywords: Reference values; Exercise test; Walking.

In its 1991revision, the American Thorax Society (ATS) recommended that each region should define its own equations to determine the theoretical, or predicted values of the spirometric parameters that best represent the pulmonary functional reality of the local population. At that time, the United States already had various equations of its own as well as the European Community, specially Poland. In 1992, Pereira et al., analysing 4,200 spirograms on healthy Brazilians, found predicted values (PV) of forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1) and middle expiratory flow (MEF) different from those reported by American and European authors. The purpose of the present study was to compare the equations developed by Pereira et al., using a Brazilian sample population, with those determined by Knudson et al. for American populations, that are the most used by Brazilian specialists. This study included 1,070 spirograms performed in patients of both genders (389 males and 681 females) who came to our service for routine functional assessment. No pathology was excluded and the smoking status of the patients was not taken into account. For each patient the PV of FVC, FEV1 and MEF were calculated accordingly to the equations of Pereira et al. (PV-P) and Knudsen et al. (PV-K). Subsequently, the means, standard deviations and reports obtained by both methods were compared. Among females, the PV-K of FVC were 4,01% (p < 0.005) greater, leading to a higher rate of restrictive impairment whereas among males there was no significant difference. Regarding FEV1, PV-P were higher in both males (4.76%; p < 0.005) and females (5.04%; p < 0.05) resulting in a greater sensitivity in the identification of respiratory obstructions. No significant difference was observed between PV-P and PV-K as to FEF25-75 regardless of gender.

Keywords: Spirometry. Reference values. Forced expiratory flow rates.

Objectives: Several equations for calculating maximal inspiratory pressure (MIP) have been validated for the Brazilian population; however, none exist for maximal dynamic inspiratory muscle pressure (S-Index). Methods: This cross-sectional study was conducted at two centers following approval by the institutional ethics committee. Healthy Brazilian adults were sequentially randomized to assess either the MIP or S-Index. Pulmonary function (spirometry), peripheral muscle strength (handgrip strength of the dominant upper limb - HGdUL), and physical activity level (IPAQ) were also evaluated. The S-Index and MIP values were reported as absolute values and compared using the Wilcoxon paired test. Multiple linear regression was used to develop reference equations. Lower limits of normality (LLNs) were stratified by sex and age using Z-scores, providing cut-off points to define inspiratory muscle weakness via the S-Index Deviation Score (SDS). Results: The final sample comprised 214 eutrophic volunteers, 50% men, with a mean age of 43.1 ± 15.0 years. The median MIP was significantly higher than the median S-Index (97.2 [96.7-112.0] vs. 92.5 [80.0-105.0] cmH2O; p<0.001). The predicted equation for the S-Index, which used age, sex, and HGdUL as predictors, was: S-Index = 69.72 + 10.765×sex (men = 1; women = 0) - 0.211×age + 0.797×HGdUL. Additionally, the LLNs and cut-off points for ventilatory muscle weakness by sex and age group were established. Conclusions: This study provides the first reference values for the S-Index in healthy, eutrophic Brazilian adults, including LLNs and cut-off points for diagnosing ventilatory muscle weakness.

Keywords: Respiratory muscle strength; S-Index; Respiratory muscle assessment.

Objective: To develop regression equations for predicting six-minute and incremental shuttle walk distances (6MWD and ISWD, respectively), based on demographic characteristics, anthropometric variables, and grip strength. Methods: We evaluated 6MWD and ISWD in 98 healthy adults. Height, weight, and grip strength were also assessed. Using data from 90 of the participants (40 males; 60 ± 9 years of age), we devised linear equations adjusted for age, gender, height, and weight, and we developed alternate models that included grip strength. We prospectively applied the equations in the 8 remaining participants (4 males; 59 ± 10 years), who had been randomly separated from the initial sample. Results: Age, gender, height, and weight collectively explained 54.5% and 64.9% of the variance in 6MWD and ISWD, respectively, whereas age, height, weight, and grip strength collectively explained 54.4% and 69.0% of the respective variances. There was no significant difference between the measured and predicted 6MWD using equations with and without grip strength (14 ± 57 vs. 13 ± 67 m). Similar results were observed for ISWD (25 ± 104 vs. 25 ± 93 m). Conclusions: Grip strength is a determinant of ISWD and 6MWD; however, it could not improve the power of equations adjusted by demographic and anthropometric variables. The validity of our models including grip strength should be further evaluated in patients with skeletal muscle dysfunction.

Keywords: Walking; Exercise; Reference Values; Exercise test.

Objective: To derive reference values for healthy white Brazilian adults who have never smoked and to compare the obtained values with reference values derived by Crapo and by Neder. Methods: Reference equations by quantile regressions were derived in 122 men and 122 women, non-obese, living in seven cities in Brazil. Age ranged from 21 to 92 years in women and from 25 to 88 years in men. Lung function tests were performed using SensorMedics automated body plethysmographies according ATS/ERS recommendations. Lower and upper limits were derived by specific equations for 5 and 95 percentiles. The results were compared to those suggested by Crapo in 1982, and Neder in 1999. Results: Median values for total lung capacity (TLC) were influenced only by stature in men, and by stature and age in women. Residual volume was influenced by age and stature in both genders. Weight was directly related to inspiratory capacity and inversely with functional residual capacity and expiratory reserve volume in both genders. A comparison of observed TLC data with values predicted by Neder equations showed significant lower values by the present data. Mean values were similar between data from present study and those derived by Crapo. Conclusion: New predicted values for lung volumes were obtained in a sample of white Brazilians. The values differ from those derived by Neder, but are similar to those derived by Crapo.

Keywords: Pulmonary volumes; Pulmonary function tests; Reference values; Pulmonary plethysmography

Objective: To derive reference equations for spirometry in healthy Black adult never smokers in Brazil, comparing them with those published in 2007 for White adults in the country. Methods: The examinations followed the standards recommended by the Brazilian Thoracic Association, and the spirometers employed met the technical requirements set forth in the guidelines of the American Thoracic Society/European Respiratory Society. The lower limits were defined as the 5th percentile of the residuals. Results: Reference equations and limits were derived from a sample of 120 men and 124 women, inhabitants of eight Brazilian cities, all of whom were evaluated with a flow spirometer. The predicted values for FVC, FEV1 , FEV1 /FVC ratio, and PEF were better described by linear equations, whereas the flows were better described by logarithmic equations. The FEV1 and FVC reference values derived for Black adults were significantly lower than were those previously derived for White adults, regardless of gender. Conclusions: The fact that the predicted spirometry values derived for the population of Black adults in Brazil were lower than those previously derived for White adults in the country justifies the use of an equation specific to the former population.

Keywords: Spirometry; Reference values; African continental ancestry group.

Objective: To determine reference values for incremental shuttle walk distance (ISWD) and peak physiological responses during the incremental shuttle walk test (ISWT), as well as to develop a series of predictive equations for those variables in healthy adults. Methods: We evaluated 103 healthy participants ≥ 40 years of age (54 women and 49 men). We fitted each participant with a gas analysis system for use during the ISWT. Oxygen consumption (VO2), carbon dioxide production, minute ventilation, heart rate (HR), ISWD, and maximal walking velocity (MWV) were obtained as primary outcomes. We also assessed hand grip strength (HGS) and lean body mass (LBM). Results: The regression analysis models, including physiological variables, ISWD, and MWV (adjusted for age, body mass, height, and sex), produced R2 values ranging from 0.40 to 0.65 (for HR and peak VO2, respectively). Using the models including LBM or HGS, we obtained no significant increase in the R2 values for predicting peak VO2, although the use of those models did result in slight increases in the R2 values for ISWD and MWV (of 8% and 12%, respectively). The variables ISWD, MWV, and ISWD Î body mass, respectively, explained 76.7%, 73.3%, and 81.2% of peak VO2 variability. Conclusions:áOur results provide reference values for ISWD and physiological responses to the ISWT, which can be properly estimated by determining simple demographic and anthropometric characteristics in healthy adults ≥ 40 years of age. The ISWT could be used in assessing physical fitness in the general adult population and in designing individualized walking programs.

Keywords: Reference values; Pulmonary gas exchange; Walking; Exercise test.

Objective: The objectives of this study were to determine reference values for sniff nasal inspiratory pressure (SNIP) and to propose reference equations for the population of Brazil. Methods: We evaluated 243 healthy individuals (111 males and 132 females), between 20 and 80 years of age, with an FVC and FEV1/FVC ratio > 80% and > 85% of the predicted value, respectively. All of the subjects underwent respiratory muscle strength tests to determine MIP, MEP, and SNIP. Results: We found that SNIP values were higher in males than in females (p < 0.05) and that SNIP correlated negatively with age, for males (r = −0.29; p < 0.001) and for females (r = −0.33; p < 0.0001). Linear regression also revealed that age influenced the predicted SNIP, for males (R2 = 0.09) and females (R2 = 0.10). We obtained predicted SNIP values that were higher than those obtained for other populations. Conclusions: We have devised predictive equations for SNIP to be used in adults (20-80 years of age) in Brazil. These equations could help minimize diagnostic discrepancies among individuals.

Keywords: Respiratory Muscles; Respiratory Function Tests; Reference Values; Linear Models.

Objective: To describe spirometric reference equations for healthy Brazilian adults who have never smoked and to compare the predicted values with those derived in 1992. Methods: Reference equations for spirometry were derived in 270 men and 373 women living in eight cities in Brazil. Ages ranged from 20 to 85 years in women and from 26 to 86 years in men. Spirometry examinations followed the recommendations of the Brazilian Thoracic Society. Lower limits were derived by the analysis of the fifth percentiles of the residuals. Results: Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC and FEV1/forced expiratory volume in six seconds (FEV6) were best fitted by linear regression. Flows were best fitted using log equations. For both genders, greater height resulted in lower values for FEV1/FVC, FEV1/FEV6 and flow/FVC ratios. The reference values for FEV1 and FVC in the present study were higher than those derived for Brazilian adults in 1992. Conclusion: New predicted values for forced spirometry were obtained in a sample of white Brazilians. The values are greater than those obtained in 1992, probably due to technical factors.

Keywords: Spirometry; Reference Values; Respiratory Function Tests.

Objective: To compare the reference values for PEF suggested by other authors in 1963, 1989 and 2001 (for populations in the USA, England and Cuba, respectively) with those obtained from a population sample in the city of São Carlos, Brazil, and to determine whether there is concordance among them. Methods: A total of 243 volunteers (123 females and 120 males; 20-70 years of age) participated in the study. The PEF measurements were performed with the volunteer standing, using a nose clip, by means of a portable peak flow meter. These measurements were compared with the reference values using the Friedman test and Dunn's post-hoc test (p < 0.05). Results: Significant differences were found in all age groups from both genders regarding the values predicted in 1989; the same occurred in the 20-30 and 31-40 age groups (both genders), as well as in the 61-70 age group (females only), regarding those predicted in 2001, as well as in the 20-30 age group (males only) regarding those predicted in 1963. Conclusions: The values predicted in 1963 are appropriate for a population of individuals with the same characteristics as the study sample, except for males in the 20-30 age group. Our study is relevant due to the fact that our sample was larger than that evaluated in the 1963 study. The majority of the values predicted in 1989 and 2001 overestimated the PEF values obtained in our study, proving to be inappropriate for the population studied.

Keywords: Reference values; Respiratory function tests; Airway obstruction; Peak expiratory flow rate.

Objective: To evaluate the spirometry values predicted by the 2012 Global Lung Function Initia-tive (GLI) equations, which are recommended for international use, in comparison with those obtained for a sample of White adults used for the establishment of reference equations for spirometry in Brazil. Methods: The sample comprised 270 and 373 healthy males and females, respectively. The mean differences between the values found in this sample and the predicted values calculated from the GLI equations for FVC, FEV1, and VEF1/FVC, as well as their lower lim-its, were compared by paired t-test. The predicted values by each pair of equations were com-pared in various combinations of age and height. Results: For the males in our study sample, the values obtained for all of the variables studied were significantly higher than those predicted by the GLI equations (p < 0.01 for all). These differences become more evident in subjects who were shorter in stature and older. For the females in our study sample, only the lower limit of the FEV1/FVC ratio was significantly higher than that predicted by the GLI equation. Conclusions: The predicted values suggested by the GLI equations for White adults were significantly lower than those used as reference values for males in Brazil. For both genders, the lower limit of the FEV1/FVC ratio is significantly lower than that predicted by the GLI equations.

Keywords: Respiratory function tests/statistics and numerical data; Respiratory function tests/diagnosis; Reference values.

Objective: To derive reference values from white race adults, for DCO in a sample from different sites in Brazil, through the same equipment model (Sensormedics), and compare the results with the derivatives from Crapo, Miller, Neder equations and from the Global Lung Initiative (GLI) proposal. Methods: The tests were performed according to the norms suggested by ATS/ERS in 2005 in six Brazilian cities, with 120 adult volunteers of each gender, non-smokers, without referred anemia and without lung or cardio diseases. The expected values were derived from linear regressions and the differences between the values forecasted by some authors and the ones observed in the current study were calculated. Results: Among men, the age varied between 25 and 88 years old, and the height varied between 140 and 176 cm. DCO was correlated significantly and positively with the height and negatively with the age. The values forecasted by Crapo, Neder, and Miller equations were higher in comparison with the ones obtained by the current study (p<0.01) in both genders. Among men, the values did not differ when compared to the ones calculated by GLI (p=0.29); among women, the values derived by GLI were slightly higher: 0.99 ml/min/mmHg (p<0.01). Conclusion: new values forecasted for DCO were derived in a sample of white adults in Brazil. The forecasted values are similar to the ones complied by GLI equations and differ from the previously proposed equations.

Keywords: Transfer factor; Pulmonary diffusing capacity; Diffusion; Carbon monoxide; Reference values; Lung function tests.

Objective: To establish reference values for cellularity in induced sputum samples collected from healthy adults. Methods: Induced sputum samples were obtained from 88 healthy adult never-smokers (39 males). The mean age was 36 years (range, 18-68 years). The participants had been residing in the city of Florianópolis, Brazil (a medium-sized non-industrial city) for at least two years. After the samples had been processed, we obtained total and differential cell counts. Results: The mean total cell count was 4.8 ± 4.2 × 106 cells/g. There was a predominance of macrophages (mean, 77.5 ± 14.7%) and neutrophils (mean, 23.4 ± 14.3%). Eosinophils were virtually absent (mean, 0.1 ± 0.3%). Lymphocytes and bronchial epithelial cells were scarce. Neither age nor atopy had any effect on the total or differential cell counts. Conclusions: In the induced sputum of this healthy adult population, macrophages and neutrophils predominated. However, the proportion of neutrophils was lower than that reported in previous studies, which suggests that reference values might vary depending on geographic location.

Keywords: Sputum; Reference values; Brazil.

Objective: To determine the intrarater and interrater reliability of cirtometry (measurements of the circumference of the chest and abdomen taken during respiratory movements) as well as its correlation with pulmonary volumes measured by respiratory inductive plethysmography. Methods: A total of 40 healthy individuals were evaluated. The mean age was 28 years. The measurements were taken in the supine position at three different time points: at rest, at maximal inspiration, and at maximal expiration. Two trained investigators, each of whom was blinded as to the results obtained by the other, performed the measurements. The Friedman test was used to determine intrarater reliability, and the Wilcoxon test, together with the intraclass correlation coefficient, were used to determine interrater reliability. The correlation between the cirtometry measurements and the plethysmography results was obtained using Spearman's correlation coefficient. The level of significance was set at 0.05 for all tests. Results: Intrarater reliability was satisfactory. Regarding interrater reliability, statistically significant differences (2.8 cm at the most) were found in all sets of measurements. However, through the analysis of the intraclass correlation coefficient, the investigators were found to be responsible only for a small portion of the variability (1.2-5.08%) found among the measurements. When the cirtometry measurements were compared to the volumes measured by respiratory inductive plethysmography, low correlations (range, r = 0.170-0.343) were found. Conclusions: The findings of this study suggest that, although cirtometry is a reliable measurement, it does not accurately measure pulmonary volumes.

Keywords: Reproducibility of results; Lung volume measurements; Plethysmography; Statistics, nonparametric.