Exhaled nitric oxide and screening for occupational asthma in two at-risk sectors: bakery and hairdressing

Int J Tuberc Lung Dis. 2014 Jun;18(6):744-50. doi: 10.5588/ijtld.13.0641.


Background: Fractional exhaled nitric oxide (FENO) levels are increasingly being used in the diagnosis and management of asthma. However, this indicator has rarely been used to detect occupational asthma.

Objective: To examine non-invasive methods to estimate airway inflammation.

Methods: A nested case-control study was conducted among a retrospective cohort of young workers in the bakery, pastry-making and hairdressing industries. Subjects underwent a clinical examination during a medical visit. Blood samples were collected and FENO levels measured. Cases were subjects diagnosed as suffering from 'confirmed' or 'probable' occupational asthma.

Results: Of the 178 workers included in the study, 19 were cases. In univariate analysis, FENO was associated with case/control status, and height and smoking status. In a multiple linear regression model, case/control status (P < 0.001), height (P = 0.006) and smoking status (P < 0.001) remained independent risk factors for variations in FENO levels. Good or fair sensitivity of respectively around 80% and 70% can be achieved using low FENO thresholds (8.5 and 10.5 ppb, respectively). FENO >8.5 ppb and a positive clinical examination increases specificity without loss of sensitivity (to 80.5% and 79.0%, respectively).

Conclusion: This study suggests that FENO measurements alone cannot be considered a useful screening test for occupational asthma. Further investigations are needed to investigate the use of combined FENO and questionnaire or repeated measures.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Asthma, Occupational / diagnosis*
  • Asthma, Occupational / metabolism
  • Asthma, Occupational / physiopathology
  • Beauty Culture*
  • Biomarkers / metabolism
  • Breath Tests*
  • Chi-Square Distribution
  • Cooking*
  • Exhalation*
  • Female
  • Food Industry*
  • Humans
  • Linear Models
  • Lung / metabolism*
  • Lung / physiopathology
  • Male
  • Nitric Oxide / metabolism*
  • Nonlinear Dynamics
  • Occupational Health
  • Predictive Value of Tests
  • Retrospective Studies
  • Risk Factors
  • Young Adult


  • Biomarkers
  • Nitric Oxide