Can air pollution affect tear film stability? a cross-sectional study in the aftermath of an explosion accident

摘要

Background: After an explosion and fire in two tanks containing contaminated oil and sulphur products in aNorwegian industrial harbour in 2007, the surrounding area was polluted. This caused an intense smell, lasting untilthe waste was removed two years later. The present study reports examinations of tear film break up time amongthe population. The examinations were carried out because many of the people in the area complained of soreeyes. The purpose of the study was to assess the relationship between living or working close to the polluted areaand tear film stability one and a half years after the explosion.Methods: All persons working or living in an area less than six kilometres from the explosion site were invited totake part in the study together with a similar number of persons matched for age and gender living more than 20kilometres away. Three groups were established: workers in the explosion area and inhabitants near the explosionarea (but not working there) were considered to have been exposed, and inhabitants far away (who did not workin the explosion area) were considered to be unexposed. A total of 734 people were examined, and the responserate was 76 percent. Tear film stability was studied by assessing non-invasive break-up time (NIBUT) using ocularmicroscopy. In addition Self-reported Break Up Time (SBUT) was assessed by recording the time the subject couldkeep his or hers eyes open without blinking when watching a fixed point on a wall. Background information wasobtained using a questionnaire. Non-parametric Wilcoxon-Mann-Whitney-tests with exact p-values and multiplelogistic regression analyses were performed.Results: Both NIBUT and SBUT were shorter among the male exposed workers than among the inhabitants bothnear and far away from the explosion area. This was also found for SBUT among males in a multiple logisticregression analysis, adjusting for age and smoking.