[The reference values selection and validity check also are a spirometry quality issue]. / Anche la scelta e la validazione dei valori teorici di riferimento sono un problema di qualità della spirometria.

Spirometric measurements are widely used for routine clinical assessment of workers with occupational exposures to bronchial irritants or sensibilizing agents, however their interpretation requires appropriate reference values for predicting normality. We studied 1319 subjects 18-25 years old (754 males--57.1% e 565 females--42.9%) with BAIRES-Biomedin spirometer and observed values were compared with different reference equations for italian workers: CECA 1971, ERS 1993, Scotti and coll. 1986, Pistelli and coll. 2000. All reference equations studied have significantly differences for one or more index, even if the observed values are all near to 100% of predicted values. The ERS 1993 reference values were always statistically different from observed values. In conclusion we suggest prudence in interpreting spirometry in young people and we hope the identification of new spirometry reference values for Italian people.

Bronchial reactivity in a general population of north Italy: relationships with occupational exposure.

Two thousand eight hundred and forty one subjects, aged 8-73 yrs, took part in the second cross-sectional survey in the Po River Delta area: among them, a subsample of currently employed people, aged 14-71 yrs, was chosen to establish the relationship between occupational exposure to dusts, chemicals or gases and respiratory symptoms, lung function and bronchial reactivity. Each subject filled out the Italian National Research Council (CNR) standardized questionnaire concerning respiratory symptoms, diseases and risk factors. A variable proportion of subjects performed acceptable forced and slow vital capacity manoeuvres, diffusing capacity of carbon monoxide and bronchial challenge test to methacholine. Occupational exposure appeared to be related to prevalence rate of respiratory symptoms (wheeze, dyspnoea, presence of at least one respiratory symptom) and bronchial asthma. Consistent effects on lung function were not evident. With respect to the bronchial challenge test, using the measurement of the provocative dose producing a 20% fall in forced expiratory volume in one second (PD20) a significantly higher percentage of hyperreactive subjects was found among ex-smoker exposed men; a borderline higher percentage of hyperreactive subjects was also found in non-smoker exposed women. The study findings support the suggestion that occupational exposure may play a role in the development of airway obstructive diseases.