Riassunto

Background It has been suggested that dust exposure causes airway inflammation among cement factory workers. However, there is limited information on the mechanisms of this effect. We explored any associations between total dust exposure and fractional exhaled nitric oxide (FENO) as a marker of airway eosinophilic inflammation among cement production workers in Tanzania. We also examined possible differences in FENO concentration between workers in different parts of the production line.

Methodology We examined 127 cement workers and 28 controls from a mineral water factory. An electrochemistry-based NIOX MINO device was used to examine FENO concentration. Personal total dust was collected from the breathing zone of the study participants using 37 mm cellulose acetate filters placed in three-piece plastic cassettes. Interviews on workers’ background information were conducted in the Swahili language.

Results We found equal concentrations of FENO among exposed workers and controls (geometric mean (GM)=16 ppb). The GM for total dust among the exposed workers and controls was 5.0 and 0.6 mg/m3, respectively. The FENO concentrations did not differ between the exposed workers with high (GM≥5 mg/m3) and low (GM<5 mg/m3) total dust exposure. There was no significant difference in FENO concentration between workers in the two main stages of the cement production process.

Conclusions We did not find any difference in FENO concentration between dust-exposed cement workers and controls, and there were similar FENO concentrations among workers in the two main stages of cement production.

Commento

L’associazione tra esposizioni professionali a polveri di cemento e lo sviluppo di sintomi respiratori cronici e/o patologie delle vie aeree rappresenta un argomento ampiamente dibattuto in letteratura.

In una serie di studi realizzati Mwaiselage e collaboratori tra il 2004 e il 2006 è emerso che i lavoratori professionalmente esposti presentavano un elevato rischio di sviluppare BPCO a causa dell’ esposizione cumulativa a tali polveri ed indipendentemente dall’abitudine al fumo di sigaretta. Lo studio sottolineò come il TLV-TWA per esposizioni a polvere di cemento di Portland (attualmente di 1 mg/m3, ACGIH) fosse ad un livello troppo elevato per prevenire i potenziali effetti patologici sull’apparato respiratorio dei lavoratori esposti.

Il meccanismo patogenetico che è alla base di questi effetti ed i componenti del cemento che ne sono responsabili continuano tuttavia a rimanere non completamente chiariti. La patogenesi maggiormente accreditata appare legata ad una irritazione cronica della membrana mucosa, causata della alcalinità del cemento e dall’azione dei composti in esso contenuti, con conseguente stimolazione delle citochine e della risposta infiammatoria sia umorale che cellulo-mediata.

Il presente studio, realizzato da due gruppi di ricerca in Norvegia e Tanzania, è il primo a considerare, in lavoratori esposti a polveri di cemento, i livelli di ossido nitrico presenti nell’aria espirata come biomarker precoce di infiammazione delle vie aeree.

Keywords

cement workers, dust exposure, nitric oxide

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