[Prevalence of respiratory problems in workers at two manufacturing centers of ready-made concrete in Morocco]

Employees at factories for ready-made concrete are exposed to the dust emanating from the products (such as sand, gravel and cement); however, there have been few studies on the subject.

A retrospective cohort analysis was conducted in a male population: 120 employees working in cement production and 120 non-exposed civil servants working at the Casa-Anfa prefecture. Each employee underwent interview by standardised questionnaire, spirometry test and standard chest radiography.

Statistical analysis of the results revealed an increase in the prevalence of exposed symptomatic subjects compared to non-exposed subjects (57.5% vs. 24.2%) and increased prevalence of all of the symptoms: cough (15.8% vs. 15%), dyspnea (21.6% vs. 5%), chronic bronchitis (11.7% vs. 6.7%), asthma (14.2% vs. 7.5%), rhinitis (40% vs. 19.2%), conjunctivitis (48.3% vs. 10%) and dermatitis (22.5% vs. 6.7%). This increase is only statistically significant for dyspnea, rhinitis, conjunctivitis and dermatitis. Changes in lung function parametres were much more frequent among the workers at the two factories than among the non-exposed workers (40.8% vs. 11.7%). Tobacco also seemed to have an effect on respiratory deficit. Analysis of the chest radiographs of the exposed subjects, using the ILO international classification, revealed 19 (15.8%) abnormal films.

Working conditions in cement factories must be improved rapidly (particularly collective technical prevention) and a medical service should be set up for regular management and follow-up of the workers.