EDITORIAL
INT J TUBERC LUNG DIS 18(6):634 Q 2014 The Union http://dx.doi.org/10.5588/ijtld.14.0299
Exhaled nitric oxide as a screening tool for occupational asthma Occupational asthma (OA) is a prevalent occupational lung disease that persists in most cases even after removal from exposure. Approximately two thirds of workers suffering from OA continue to have symptomatic asthma after their removal from exposure in the workplace.1 A high risk of a negative outcome of OA is related to the severity of the disease at the time of its diagnosis,2 while the persistence of exposure after being diagnosed with OA is associated with a worsening of the disease.3 Therefore, early detection of OA is key to ensuring a substantial decrease in the subsequent severity of the disease. Post-employment screening programmes have been developed in several settings.4 These usually include a combination of several tools such as questionnaires, a spirometry test, an airway responsiveness measure, skin prick tests and/or a specific IgE measure. So far, no single screening tool has shown optimal efficacy for the early detection of OA. The measurement of fractional concentrations of exhaled nitric oxide (FeNO) is increasingly being used in the management of asthma as a non-invasive measure of airway inflammation, which is also one of the main characteristics of OA. However, the use of FeNO is still controversial in the diagnosis and management of OA. Although a pilot study has suggested that FeNO may be useful as a screening tool for OA among laboratory animal workers,5 no large screening programme has included a noninvasive measure of inflammation among the tools used for OA screening. In this issue of the Journal, Florentin et al. explore the use of FeNO as a screening tool in a population of workers at risk of developing OA: bakers, pastry makers and hairdressers.6 They identified an 8.5 ppb FeNO threshold as having 78.9% sensitivity and 42.8% specificity in identifying OA. The addition of a questionnaire to this test substantially improved the specificity (80.5%) without changing its sensitivity. This article underlines the need to improve the
medical surveillance of subjects at risk of developing OA. FeNO is easy to perform and can be measured in the workplace. Although FeNO does not appear to be reliable as a single screening tool, as its use would likely generate both false-positive and -negative diagnoses, its use in combination with a screening questionnaire for OA needs further evaluation. The present study was retrospective and included a limited number of subjects with OA (n ¼ 19). There is thus a need for a prospective assessment of the combination of several tests and questionnaires that can feasibly be used in the workplace, including a non-invasive measure of inflammation, in order to build an efficient screening programme for populations of workers at risk of developing OA. CATHERINE LEMIERE, MD, MSC Department of Chest Medicine Sacre-Coeur Hospital ´ Montreal, Quebec, Canada e-mail: [email protected] References 1 Rachiotis G, Savani R, Brant A, MacNeill S J, Newman Taylor A, Cullinan P. Outcome of occupational asthma after cessation of exposure: a systematic review. Thorax 2007; 62: 147–152. 2 Maestrelli P, Schlunssen V, Mason P, Sigsgaard T. Contribution of host factors and workplace exposure to the outcome of occupational asthma. Eur Respir Rev 2012; 21: 88–96. 3 Vandenplas O, Dressel H, Nowak D, Jamart J. What is the optimal management option for occupational asthma? Eur Respir Rev 2012; 21: 97–104. 4 Wilken D, Baur X, Barbinova L, et al. What are the benefits of medical screening and surveillance? Eur Respir Rev 2012 ; 21: 105–111. 5 Hewitt R S, Smith A D, Cowan J O, Schofield J C, Herbison G P, Taylor D R. Serial exhaled nitric oxide measurements in the assessment of laboratory animal allergy. J Asthma 2008; 45: 101– 107. 6 Florentin A, Acouetey D-S, Remen T, et al. Exhaled nitric oxide and screening for occupational asthma in two at-risk sectors: bakery and hairdressing. Int J Tuberc Lung Dis 2014; 18: 000000 [Setters: in this issue. ED]
INT J TUBERC LUNG DIS 18(6):634 Q 2014 The Union http://dx.doi.org/10.5588/ijtld.14.0299
Exhaled nitric oxide as a screening tool for occupational asthma Occupational asthma (OA) is a prevalent occupational lung disease that persists in most cases even after removal from exposure. Approximately two thirds of workers suffering from OA continue to have symptomatic asthma after their removal from exposure in the workplace.1 A high risk of a negative outcome of OA is related to the severity of the disease at the time of its diagnosis,2 while the persistence of exposure after being diagnosed with OA is associated with a worsening of the disease.3 Therefore, early detection of OA is key to ensuring a substantial decrease in the subsequent severity of the disease. Post-employment screening programmes have been developed in several settings.4 These usually include a combination of several tools such as questionnaires, a spirometry test, an airway responsiveness measure, skin prick tests and/or a specific IgE measure. So far, no single screening tool has shown optimal efficacy for the early detection of OA. The measurement of fractional concentrations of exhaled nitric oxide (FeNO) is increasingly being used in the management of asthma as a non-invasive measure of airway inflammation, which is also one of the main characteristics of OA. However, the use of FeNO is still controversial in the diagnosis and management of OA. Although a pilot study has suggested that FeNO may be useful as a screening tool for OA among laboratory animal workers,5 no large screening programme has included a noninvasive measure of inflammation among the tools used for OA screening. In this issue of the Journal, Florentin et al. explore the use of FeNO as a screening tool in a population of workers at risk of developing OA: bakers, pastry makers and hairdressers.6 They identified an 8.5 ppb FeNO threshold as having 78.9% sensitivity and 42.8% specificity in identifying OA. The addition of a questionnaire to this test substantially improved the specificity (80.5%) without changing its sensitivity. This article underlines the need to improve the
medical surveillance of subjects at risk of developing OA. FeNO is easy to perform and can be measured in the workplace. Although FeNO does not appear to be reliable as a single screening tool, as its use would likely generate both false-positive and -negative diagnoses, its use in combination with a screening questionnaire for OA needs further evaluation. The present study was retrospective and included a limited number of subjects with OA (n ¼ 19). There is thus a need for a prospective assessment of the combination of several tests and questionnaires that can feasibly be used in the workplace, including a non-invasive measure of inflammation, in order to build an efficient screening programme for populations of workers at risk of developing OA. CATHERINE LEMIERE, MD, MSC Department of Chest Medicine Sacre-Coeur Hospital ´ Montreal, Quebec, Canada e-mail: [email protected] References 1 Rachiotis G, Savani R, Brant A, MacNeill S J, Newman Taylor A, Cullinan P. Outcome of occupational asthma after cessation of exposure: a systematic review. Thorax 2007; 62: 147–152. 2 Maestrelli P, Schlunssen V, Mason P, Sigsgaard T. Contribution of host factors and workplace exposure to the outcome of occupational asthma. Eur Respir Rev 2012; 21: 88–96. 3 Vandenplas O, Dressel H, Nowak D, Jamart J. What is the optimal management option for occupational asthma? Eur Respir Rev 2012; 21: 97–104. 4 Wilken D, Baur X, Barbinova L, et al. What are the benefits of medical screening and surveillance? Eur Respir Rev 2012 ; 21: 105–111. 5 Hewitt R S, Smith A D, Cowan J O, Schofield J C, Herbison G P, Taylor D R. Serial exhaled nitric oxide measurements in the assessment of laboratory animal allergy. J Asthma 2008; 45: 101– 107. 6 Florentin A, Acouetey D-S, Remen T, et al. Exhaled nitric oxide and screening for occupational asthma in two at-risk sectors: bakery and hairdressing. Int J Tuberc Lung Dis 2014; 18: 000000 [Setters: in this issue. ED]
