[Which definition to use when defining airflow obstruction?]

[An epidemiological and evolutionary profile of occupational asthma of Tunisian workers]

INTRODUCTION

This study aims to identify the epidemiological and occupational characteristics of patients with occupational asthma (OA) and to assess their clinical evolution and occupational outcomes.

METHODS

We carried out a descriptive epidemiological study over a period of five years (from 2012 to 2016) about the OA cases in the private sector reported in the Tunisian region of Zaghouan.

RESULTS

All in all, 165 OA cases were reported during the study period, representing an annual incidence of 733.3 cases per 1,000,000 workers in the private sector. Our study population was composed predominantly (85.5%) of women, whose mean age was 41.5±6.8years. More than three quarters of the affected persons were working in the automobile industry, and most illnesses (77%) were attributable to isocyanates. The mean time to onset of the respiratory symptoms was longer for low molecular weight agents (13.6±3.1years) compared to high molecular weight agents (12.0±3.9years) (P=0.0006). The majority of OA cases (66.7%) lost their jobs. Job loss was significantly more frequent among asthmatic women and workers with OA due to isocyanates. Among the 62 cases of OA for whom risk factors were eliminated, 45 nonetheless remained symptomatic.

CONCLUSION

Effective prevention strategies involving the various actors need to be implemented in work environments so as to reduce the frequency and the medico-legal repercussions of a disabling condition.

[Systemic inflammatory profile of smokers with and without COPD]

INTRODUCTION

Studies comparing the systemic inflammatory profiles of smokers with and without COPD present discordant findings.

AIM

To compare the systemic inflammatory profile of smokers with and without COPD.

METHODS

This is a cross-sectional comparative study. Two groups of active smokers of more than 10 pack-years were included: 56 consecutives stable COPD (postbronchodilator FEV₁/FVC<0.70) and 32 consecutives non-COPD (postbronchodilator FEV₁/FVC≥0.70). Smoking and clinical, anthropometric and spirometric data were noted. The following blood biomarkers were identified: leukocytes, hemoglobin, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR). According to the levels (normal/abnormal) of these markers, two groups of smokers were formed. Quantitative and qualitative data were expressed, respectively, as means±SD and percentages.

RESULTS

Compared to the non-COPD group, the COPD group was older (56±12 vs. 65±8 years) and had a higher smoking consumption (30±18 vs. 52±31 pack-years). Compared to the non-COPD group, the COPD group had higher values of CRP (2.06±1.24 vs. 11.32±11.03mg/L), of ESR (9.59±8.29 vs. 15.96±11.56), of IL-6 (9.28±4.69 vs. 20.27±5.31ng/L) and of TNF-α (18.38±7.98ng/L vs. 8.62±3.72ng/L). Compared to the non-COPD group, the COPD group included higher percentages of smokers with elevated CRP (0 % vs. 32 %), with leukocytosis (6 % vs. 16 %), with higher levels of IL-6 (81 % vs. 98 %) or TNF-α (91 % vs. 100 %).

CONCLUSION

Smokers with COPD, compared to smokers free from COPD, have a marked systemic inflammation.

[Occupational asthma compensation in the Tunisian Center: cross-sectional study over a period of eight years]

INTRODUCTION

Our study aimed to highlight the epidemiological profile of patients compensated for occupational asthma in the Tunisian Center, to identify their professional characteristics and to determine compensation practices for this occupational disease.

METHODS

We conducted an exhaustive retrospective study over a period of eight years. This case study included workers with occupational asthma diagnosed and compensated in the Tunisian Center by the only two medical commissions empowered to set rates for permanent partial disability caused by either a work-related injury or an occupational diseases in the seven central governorates.

RESULTS

A total of 129 workers, with average age of 40.6 ± 7.75 years were compensated for occupational asthma during the study period. Sex ratio was 0.66. The most incriminated etiologic agents were vegetable dust pollution in the textile industry (75.2%), wood dust, flour and isocyanates. Nonspecific bronchial hyperreactivity was found in 38% of cases, a high rate of IgE in 14% of cases and positive skin prick test in 10.9% of cases. The average rate of permanent partial disability was 25.6 ± 14.2%. On the basis of the analytical study, this rate was related to patient's age and to the medical commission which had set this rate.

CONCLUSION

This study of workers compensated for occupational asthma provides relevant data about epidemiological and clinical features of diagnosed patients and committee practices in particular, in term of application of the voluntary indicative scale, but it does not allow an assessment of the prevalence of this pathology which is often underestimated.

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

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.

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Key Words

• FEV1/FVC
• fixed threshold
• guideline
• lower limit of normal
• obstructive ventilatory defect
• spirometry

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MESH Headings

• Adolescent
• Adult
• Aged
• Aged, 80 and over
• Female
• Forced Expiratory Volume
• Humans
• Male
• Middle Aged
• Pulmonary Disease, Chronic Obstructive/diagnosis
• Pulmonary Disease, Chronic Obstructive/epidemiology
• Pulmonary Disease, Chronic Obstructive/physiopathology
• Respiratory Function Tests
• Retrospective Studies
• Smoking/adverse effects
• Smoking/physiopathology
• Spirometry/methods
• Tunisia/epidemiology
• Vital Capacity

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Affiliation(s)

Zied Affes Department of Physiology and Functional Exploration, Farhat HACHED University Hospital of Sousse, Sousse, Tunisia
Salaheddine Rekik Department of Physiology and Functional Exploration, Farhat HACHED University Hospital of Sousse, Sousse, Tunisia
Helmi Ben Saad Department of Physiology and Functional Exploration, Farhat HACHED University Hospital of Sousse, Sousse, Tunisia Laboratory of Physiology, Faculty of Medicine of Sousse, University of Sousse, Sousse, Tunisia Research Laboratory N° LR14ES05: Interactions of the Cardiopulmonary System, Faculty of Medicine of Sousse, University of Sousse, Sousse, Tunisia;

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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.

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 χ(2) 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.

[Spirometric reference equations for Algerians aged 19 to 73 years]

INTRODUCTION

The validity of using European reference equations in the interpretation of spirometry results in Algerian patients has not been assessed.

AIMS

(i) to establish Algerian spirometric reference equations and (ii) to compare them with European ones.

METHODS

A medical questionnaire was administered. Gender, age, height, weight, lean mass (LM), percentage of fat mass (%FM) and body mass index (BMI) were noted. Spirometric variables were measured using a body plethysmograph according to international guidelines. Simple and multiples linear regressions were performed. The measured forced expiratory volume (FEV1), forced vital capacity (FVC) and the ratio between FEV1 and slow vital capacity (FEV1/SVC) were compared with those predicted from European reference equations.

RESULTS

273 healthy subjects (120 women) were included (age: 42+/-14 years; height: 1.69+/-0.10 m; weight: 74+/-13 kg; LM: 59+/-10 kg;%FM: 21+/-6%; BMI: 26+/-6 Kg.m-2). (i) Algerian reference equations explained 17% to 68% of the variability of parameters tested. (ii) The European reference equations significantly underestimated the measured FEV1, FVC and the FEV1/SVC ratio (respectively, 0.38+/-0.45 L, 0.36+/-0.55 L, and 0.01+/-0.06).

CONCLUSION

The use of Algerian spirometric reference equations should improve the accuracy of lung function interpretation in this population.

[Which definition to use when defining reversibility of airway obstruction?]

INTRODUCTION

There is no clear consensus about what constitutes reversibility of airway obstruction. European Respiratory Society (ERS): Increase in FEV1 and/or FVC>12% of their theoretical value and>0.2l. British Thoracic Society: FEV1>15% of initial value and FEV1>0.2l. Global Initiative for Chronic Obstructive Lung Disease: Increase in FEV1>12% and>0.2l. Australia and New Zealand Thoracic Society: Increase in FEV1 >15%. American Thoracic Society/ERS: Increase in FEV1>12% and>0.2l or increase in FVC>12% and 0.2l. Our principal objective was to determine the percentage of patients with COPD (n=62) who were significant responders to the reversibility test according to the 5 recommendations.

METHODS

Plethysmography was performed before and 15 minutes after inhalation of 400 micrograms of a short acting bronchodilator (BD). COPD is defined as a FEV1/FVC post BD<0.7.

RESULTS

The percentage of responders varied from 24% to 50% depending on the recommendations used.

CONCLUSION

Reversibility of airway obstruction is recommendation dependent.