Helmi Ben Saad

Reference equation for 6‐min walk distance in healthy North African children 6–16 years old

To assess the need for a 6‐min walk distance (6‐MWD) reference equation for healthy North African children 6–16 years old.

Effect of an overground walking training on gait performance in healthy 65- to 80-year-olds.

The aim of this study was to examine the effect of an individualized overground walking interval training on gait performance [i.e., speed and energy cost (C(w))] in healthy elderly individuals. Twenty-two older adults were assigned to either a training group (TG; n=12, 73.4+/-3.9yr) or a non-training control group (CG; n=10, 70.9+/-9.6yr). TG participated in a 7-week individualized walking interval training at intensities progressing from 50 to 100% of ventilatory threshold (T (VE)). Aerobic fitness [maximal oxygen uptake (V O(2max)) and T (VE)], preferred walking speed (PWS), gross and net C(w) (GC(w) and NC(w), respectively) and relative effort (%V O(2max)) at PWS measured before training (PWS(1)) were assessed prior and following the intervention. All outcomes were measured on a treadmill. Significant improvements in GC(w) (-8%; P=0.007), NC(w) (-12%; P=0.003), relative effort (%V O(2max): -12%; P<0.001) and PWS (+12%; P<0.001) were observed in TG but not in CG (P>0.71). V O(2max) and T (VE) remained unchanged in both groups (P>0.57). Changes in GC(w) at PWS(1) (difference between GC(w) at PWS(1) measured pre and post intervention) were inversely correlated with changes in PWS (difference between pre and post PWS; r=-0.67; P=0.02). The decreased C(w) at PWS(1), with no concomitant improvement in aerobic fitness, represents the main contributing factor for the reduction of the relative effort at this speed. This also allows elderly people to increase their PWS post training. Therefore, the present walking training may be an effective way to improve walking performance and delay mobility impairment in older adults.

Changes in six-minute walking distance during pulmonary rehabilitation in patients with COPD and in healthy subjects

Background: The six-minute walking distance (6MWD) test has demonstrated validity and reliability to assess changes in functional capacity following pulmonary rehabilitation in patients with chronic obstructive lung disease. However, no attempt has been made to establish an iterative measurement of 6MWD during the overall period of pulmonary rehabilitation. Therefore, the aim of this study was to evaluate the impact of a twelve-week rehabilitation program on the iterative weekly measurement of 6MWD in chronic obstructive pulmonary disease (COPD) patients and healthy subjects. Methods: Twenty-six patients with COPD and nine age-matched healthy subjects were studied. Measurements were taken at baseline and after twelve weeks except for the 6MWD. The exercise measurements included a six-minute walking test (6MWT) and an incremental exercise test. Oxygen saturation, heart rate, and dyspnea will be monitored during all these tests. Results: At baseline there were significant differences between groups, except in age, body mass index, and oxygen saturation. After 12 weeks, there was no significant change in lung function in patients with COPD and healthy subjects. The 6MWD, peak oxygen uptake V̇O2peak and anaerobic threshold increased significantly after training in both groups (P < 0.01). The averaged trace of the 6MWD of patients with COPD and healthy subjects was followed-up respectively by a logarithmic and linear fitting. 6MWD showed a plateau after eight weeks in patients with COPD, however, it increased continually overall in healthy subjects. Conclusion: Both patients with COPD and healthy subjects demonstrated functional responses to training but with somewhat different patterns in quality of the improvement of the 6MWD.

The forgotten message from gold: FVC is a primary clinical outcome measure of bronchodilator reversibility in COPD.

BACKGROUND The Global Initiative for Chronic Obstructive Lung Disease (GOLD) recommends the use of forced expiratory volume in 1s (FEV(1)) to assess airways reversibility. The American Thoracic Society (ATS) and the European Respiratory Society (ERS) recommend FEV(1) and/or forced vital capacity (FVC). This study assessed whether FVC detects reversibility in more chronic obstructive pulmonary disease (COPD) patients than FEV(1) after acute short-acting bronchodilator inhalation. METHODS Plethysmographic data of 168 consecutive stable male COPD patients who underwent reversibility testing were analyzed. RESULTS Seventy-seven patients showed a clinically significant increase in FVC, whereas only 49 patients showed a clinically significant increase in FEV(1). Thus, FVC detected reversibility in 57% more patients than FEV(1). Of the 90 patients showing clinically significant reversibility, FEV(1) did not detect 41 patients that FVC detected, indicating a 45% difference. CONCLUSION FEV(1) underestimates acute bronchodilation effects. FVC should thus be a primary clinical outcome measure of bronchodilator reversibility in COPD, as it detects reversibility in more patients. This message, forgotten by GOLD, should be promoted in future consensus statements.

Oxidative stress and lung function profiles of male smokers free from COPD compared to those with COPD: a case-control study

Background The mechanisms of smoking tobacco leading to chronic obstructive pulmonary disease (COPD) are beginning to be understood. However, conclusions about the role of blood or lung oxidative stress markers were disparate. Aims To investigate the oxidative stress in blood or lung associated with tobacco smoke and to evaluate its effect on pulmonary function data and its relation with physical activity. Methods It is a case-control study. Fifty-four male-smokers of more than five pack-years (PY) and aged 40-60 years were included (29 Non-COPD, 16 COPD). Physical activity score was determined. Blood sample levels of malondialdehyde (MDA), protein-cys-SH (PSH), and Glutathione (GSH) were measured. Fractional exhaled nitric oxide (FeNO) and plethysmographic measurements were performed. Correlation coefficients (r) evaluated the association between oxidative stress markers and independent variables (plethysmographic data and physical activity score). Results Non-COPD (48±6 years) and COPD (49±5 years) groups had similar tobacco consumption patterns, that is, 27±14 PY versus 30±19 PY, respectively. Compared to the Non-COPD group, the COPD group had significantly lower levels of GSH and PSH, that is, mean±SE were 40±6 versus 25±5 µg/mL and 54±10 versus 26±5 µg/g of hemoglobin, respectively. However, MDA level and FeNO values were similar. In the COPD group, none of the oxidative stress markers was significantly correlated with plethysmographic data or physical activity score. In the Non-COPD group, GSH was significantly correlated with physical activity score (r=0.47) and PSH was significantly correlated with total lung capacity (TLC) (r=-0.50), residual volume (r=0.41), and physical activity score (r=0.62). FeNO was significantly correlated with TLC of the COPD group (r=-0.48). Conclusion Compared to the Non-COPD group, the COPD group had a marked decrease in blood antioxidant markers (GSH and PSH) but similar blood oxidant (MDA) or lung (FeNO) burden.Background The mechanisms of smoking tobacco leading to chronic obstructive pulmonary disease (COPD) are beginning to be understood. However, conclusions about the role of blood or lung oxidative stress markers were disparate. Aims To investigate the oxidative stress in blood or lung associated with tobacco smoke and to evaluate its effect on pulmonary function data and its relation with physical activity. Methods It is a case-control study. Fifty-four male-smokers of more than five pack-years (PY) and aged 40–60 years were included (29 Non-COPD, 16 COPD). Physical activity score was determined. Blood sample levels of malondialdehyde (MDA), protein-cys-SH (PSH), and Glutathione (GSH) were measured. Fractional exhaled nitric oxide (FeNO) and plethysmographic measurements were performed. Correlation coefficients (r) evaluated the association between oxidative stress markers and independent variables (plethysmographic data and physical activity score). Results Non-COPD (48±6 years) and COPD (49±5 years) groups had similar tobacco consumption patterns, that is, 27±14 PY versus 30±19 PY, respectively. Compared to the Non-COPD group, the COPD group had significantly lower levels of GSH and PSH, that is, mean±SE were 40±6 versus 25±5 µg/mL and 54±10 versus 26±5 µg/g of hemoglobin, respectively. However, MDA level and FeNO values were similar. In the COPD group, none of the oxidative stress markers was significantly correlated with plethysmographic data or physical activity score. In the Non-COPD group, GSH was significantly correlated with physical activity score (r=0.47) and PSH was significantly correlated with total lung capacity (TLC) (r=−0.50), residual volume (r=0.41), and physical activity score (r=0.62). FeNO was significantly correlated with TLC of the COPD group (r=−0.48). Conclusion Compared to the Non-COPD group, the COPD group had a marked decrease in blood antioxidant markers (GSH and PSH) but similar blood oxidant (MDA) or lung (FeNO) burden.

Investigation of Exclusive Narghile Smokers: Deficiency and Incapacity Measured by Spirometry and 6-Minute Walk Test

BACKGROUND: Studies on the submaximal aerobic capacity of exclusive narghile smokers (ENS) seem necessary in view of effective prevention of cardiorespiratory diseases. The goal of the study was to assess, by 6-min walk test (6MWT) data, the submaximal aerobic capacity of ENS, to identify factors influencing their 6-min walk distance (6MWD), and to compare their data with those of a healthy non-smoker (HNS) group. METHODS: Seventy 20–60-y-old male ENS were included. Narghile use (narghile-years) and anthropometric, clinical, spirometric, and 6MWT data were collected. Univariate and multivariate analyses were used to identify factors influencing 6MWD. Data of a subgroup of 40–60-y-old ENS (n = 25) were compared with those of an age-matched HNS group (n = 53). RESULTS: The median (first to third quartile) for age and narghile use were 32 (26–43) and 17 (8–32) narghile-years, respectively. The profile of ENS performing the 6MWT was as follows: at the end of the 6MWT, 34% and 9% had a low heart rate (< 60% of maximum predicted) and high dyspnea scores (> 5/10, visual analog scale), respectively; 3% had an oxyhemoglobin saturation decrease of > 5 points during the test; and 20% had an abnormal 6MWD (less than the lower limit of the normal range). The factors that significantly influenced the 6MWD, explaining 38% of its variability, are included in the following equation: 6MWD (m) = 742.63 − 5.20 × body mass index (kg/m2) + 25.23 × FEV1 (L) − 0.44 × narghile use (narghile-years). Compared with HNS, the subgroup of ENS had a significantly lower 6MWD (98 ± 7 vs 87 ± 9% predicted, respectively). CONCLUSIONS: Narghile use may play a role in reducing submaximal aerobic capacity. The present study suggests that a program of pulmonary rehabilitation is an excellent axis to follow.

Pulmonary functions of narghile smokers compared to cigarette smokers: a case-control study

Background Studies of the lung function profiles of exclusive narghile smokers (ENS) are few, have some methodological limits, and present contradictory conclusions. The present study aimed to compare the plethysmographic profiles of ENS with age- and height-matched exclusive cigarette smokers (ECS). Methods Males aged 35–60 living in Sousse, Tunisia, who have been smoking narghile exclusively for more than 10 narghile-years (n = 36) or cigarettes exclusively for more than 10 pack-years (n = 106) were recruited to participate in this case–control study. The anthropometric and plethysmographic data were measured according to international recommendations using a body plethysmograph (ZAN 500 Body II, Meβgreräte GmbH, Germany). Large-airway-obstructive-ventilatory-defect (LAOVD) was defined as: first second forced expiratory volume/forced vital capacity (FEV1/FVC) below the lower-limit-of-normal (LLN). Restrictive-ventilatory-defect (RVD) was defined as total lung capacity < LLN. Lung hyperinflation was defined as residual volume > upper-limit-of-normal. Student t-test and χ2 test were used to compare plethysmographic data and profiles of the two groups. Results The subjects in the ENS and ECS groups are well matched in age (45±7 vs. 47±5 years) and height (1.73±0.06 vs. 1.72±0.06 m) and used similar quantities of tobacco (36±22 narghile-years vs. 35±19 pack-years). Compared to the ENS group, the ECS group had significantly lower FEV1 (84±12 vs. 60±21%), FVC (90±12 vs. 76±18%), and FEV1/FVC (99±7 vs. 83±17%). The two groups had similar percentages of RVD (31 vs. 36%), while the ECS group had a significantly higher percentage of LAOVD (8 vs. 58%) and lung hyperinflation (36 vs.57%). Conclusion Chronic exclusive narghile smoking has less adverse effects on pulmonary function tests than chronic exclusive cigarette smoking.Background Studies of the lung function profiles of exclusive narghile smokers (ENS) are few, have some methodological limits, and present contradictory conclusions. The present study aimed to compare the plethysmographic profiles of ENS with age- and height-matched exclusive cigarette smokers (ECS). Methods Males aged 35-60 living in Sousse, Tunisia, who have been smoking narghile exclusively for more than 10 narghile-years (n = 36) or cigarettes exclusively for more than 10 pack-years (n = 106) were recruited to participate in this case-control study. The anthropometric and plethysmographic data were measured according to international recommendations using a body plethysmograph (ZAN 500 Body II, Meβgreräte GmbH, Germany). Large-airway-obstructive-ventilatory-defect (LAOVD) was defined as: first second forced expiratory volume/forced vital capacity (FEV1/FVC) below the lower-limit-of-normal (LLN). Restrictive-ventilatory-defect (RVD) was defined as total lung capacity < LLN. Lung hyperinflation was defined as residual volume > upper-limit-of-normal. Student t-test and χ2 test were used to compare plethysmographic data and profiles of the two groups. Results The subjects in the ENS and ECS groups are well matched in age (45±7 vs. 47±5 years) and height (1.73±0.06 vs. 1.72±0.06 m) and used similar quantities of tobacco (36±22 narghile-years vs. 35±19 pack-years). Compared to the ENS group, the ECS group had significantly lower FEV1 (84±12 vs. 60±21%), FVC (90±12 vs. 76±18%), and FEV1/FVC (99±7 vs. 83±17%). The two groups had similar percentages of RVD (31 vs. 36%), while the ECS group had a significantly higher percentage of LAOVD (8 vs. 58%) and lung hyperinflation (36 vs.57%). Conclusion Chronic exclusive narghile smoking has less adverse effects on pulmonary function tests than chronic exclusive cigarette smoking.

Effects of Ramadan on physical capacities of North African boys fasting for the first time

Introduction Most of the literature related to the effects of Ramadan fasting on physical performance has focused on adults, and only three studies have examined its impact on childrens physical performance. Aims To examine the effects of Ramadan fasting on first-time fasting boys’ performance in short-term explosive exercises [vertical and horizontal jump tests (VJT and HJT), 20-m and 30-m sprints and medicine-ball throw (MBT)], as well as in sub-maximal endurance [6-min walking distance (6MWD) measured during the 6-min walk test (6MWT)]. Methods Eighteen Tunisian boys [mean±standard deviation (SD) of age and body mass (BM): 11.9±0.8 y and 55.4±18.2 kg, respectively] were included. The experimental design comprised four testing phases: 2-weeks before Ramadan (BR), the end of the second week (R2) and the fourth week (R4) of Ramadan, and 10–12 days after the end of Ramadan (AR). At each phase, boys performed two test sessions in the afternoon (15:00–17:00 h) interrupted by 48 h of recovery (first test session: BM, VJT, HJT, and 20-m and 30-m sprint tests; second session: MBT and 6MWT). The study was conducted during the summer of 2012 from July 5 to August 29. Results 6MWDs (m) were significantly shorter during R2 (652±101) and R4 (595±123) compared to BR (697±86) and came back to baseline values AR. BM (kg) mean±SD did not significantly change during R2 (52±15) and during R4 (53±15) compared to BR (55±17), and short-term explosive performances were unchanged throughout the study. Conclusion In non-athletic children, first-ever Ramadan fasting impairs sub-maximal aerobic capacity but has no effect on BM or short-term explosive performance.

North-African reference values of alveolar membrane diffusion capacity and pulmonary capillary blood volume.

Background: In North-African adults, location-specific reference values for membrane diffusion capacity (D_m) and pulmonary capillary blood volume (V_c) were needed. Objectives: To verify the applicability of previously published reference equations for D_m and V_c in North-African healthy adults (age >18 years) and to determine specific reference equations for North Africa. Methods: The study was designed as a prospective cross-sectional study. Anthropometric data (age, height, weight and body mass index) and D_m and V_c were assessed in 85 healthy Tunisian adults. Univariate and multiple linear regression analyses were used to determine reference equations and to calculate the lower limit of the normal range (LLN). Results: The mean ages ± SD (minimum – maximum) for male and female adults were 53 ± 21 (21–85) and 42 ± 16 (18–72) years, respectively. Previously published reference equations did not reliably predict measured D_m and V_c. The reference equation (r² = 47%) for D_m was –36.16 + 45.37 × height – 0.34 × age + 0.39 × weight + 7.41 × gender (0 = female and 1 = male). To calculate the D_m LLN subtract 24.36 from the reference value. The reference equation (r² = 30%) for female V_c was 94.70 – 0.57 × age, and the reference equation (r² = 52%) for male V_c was 0.82 – 0.48 × age + 52.47 × height + 0.16 × weight. To calculate the V_c LLN subtract 28.52 and 26.54 from these reference values for females and males, respectively. Conclusion: These V_c and D_m reference equations supplement the international World Bank of reference equations.

Defining obstructive ventilatory defect in 2015

Introduction There is no clear consensus as to what constitutes an obstructive ventilatory defect (OVD): Is it FEV1/FVC<lower limit of normal (LLN) or<0.70 (respectively, physiological and operational definitions)? Aim To determine, according to the two definitions, the percentage of subjects having an OVD among them explored in a lung function exploration laboratory. Population and methods This is a retrospective study including 4,730 subjects aged 17–85 years. Subjects were divided according to the presence [physio (+) or operat (+)] or absence [physio (−) or operat (−)] of an OVD, and into younger (<45 years, n=2,076), older (≥45 years, n=2,654), smokers (n=1,208), and non-smokers (n=3,522) groups. Results For the total sample, the younger and older groups [mean±SD of age (years), respectively, 46.7±14.1; 33.9±7.4, and 56.8±9.1], the ‘physiological definition’ detected, respectively, 13.46, 43.22, and 5.09% more OVD than the ‘operational one’ (p<0.05). In addition, the operational definition, compared with the physiological one, overdiagnosed OVD in 2.33 and 0.44% of smokers and non-smokers, respectively, and underdiagnosed it in 4.46% and 29.72% of smokers and non-smokers, respectively (p<0.05). Compared with the group ‘physio (−), operat (+)’, the ‘physio (+), operat (−)’ one was younger (74.2±4.7 years vs. 40.9±10.3 years) and had significantly higher FEV1 (62±13% vs. 78±17%) and FVC (71±15% vs. 93±19%). Conclusion The frequency of OVD much depends on the criteria used for its definition.Introduction There is no clear consensus as to what constitutes an obstructive ventilatory defect (OVD): Is it FEV1/FVC<lower limit of normal (LLN) or<0.70 (respectively, physiological and operational definitions)? Aim To determine, according to the two definitions, the percentage of subjects having an OVD among them explored in a lung function exploration laboratory. Population and methods This is a retrospective study including 4,730 subjects aged 17–85 years. Subjects were divided according to the presence [physio (+) or operat (+)] or absence [physio (−) or operat (−)] of an OVD, and into younger (<45 years, n=2,076), older (≥45 years, n=2,654), smokers (n=1,208), and non-smokers (n=3,522) groups. Results For the total sample, the younger and older groups [mean±SD of age (years), respectively, 46.7±14.1; 33.9±7.4, and 56.8±9.1], the ‘physiological definition’ detected, respectively, 13.46, 43.22, and 5.09% more OVD than the ‘operational one’ (p<0.05). In addition, the operational definition, compared with the physiological one, overdiagnosed OVD in 2.33 and 0.44% of smokers and non-smokers, respectively, and underdiagnosed it in 4.46% and 29.72% of smokers and non-smokers, respectively (p<0.05). Compared with the group ‘physio (−), operat (+)’, the ‘physio (+), operat (−)’ one was younger (74.2±4.7 years vs. 40.9±10.3 years) and had significantly higher FEV1 (62±13% vs. 78±17%) and FVC (71±15% vs. 93±19%). Conclusion The frequency of OVD much depends on the criteria used for its definition.