Ocular symptoms and tear film break up time (BUT) among junior high school students in Penang, Malaysia - Associations with fungal DNA in school dust

- Fungal DNA was found in all dust samples from the classrooms but at different levels.
- Higher levels of total DNA in classroom dust was related to impaired tear film stability.
- The associations were strongest for Aspergillus/Penicillium DNA in the dust.

BackgroundThere are few studies on ocular effects of indoor mould exposure in schools, especially in the tropicsObjectiveTo study associations between eye symptoms and tear film break up time (BUT) in students and demographic data and fungal DNA in schools.MethodsA school environment study was performed among randomly selected students in eight randomly selected secondary schools in Penang, Malaysia. Information on eye symptoms and demographic data was collected by a standardised questionnaire. BUT was measured by two methods, self-reported BUT (SBUT) and by the non-invasive Tearscope (NIBUT). Dust was collected by vacuuming in 32 classrooms and analysed for five fungal DNA sequences. Geometric mean (GM) for total fungal DNA was 7.31*104 target copies per gram dust and for Aspergillus/Penicillium DNA 3.34*104 target copies per gram dust. Linear mixed models and 3-level multiple logistic regression were applied adjusting for demographic factors.ResultsA total of 368 students (58%) participated and 17.4% reported weekly eye symptoms the last 3 months. The median SBUT and TBUT were 15 and 12 s, respectively. Students wearing glasses (OR 2.41, p = 0.01) and with a history of atopy (OR = 2.67; p = 0.008) had more eye symptoms. Girls had less eye symptoms than boys (OR = 0.34; p = 0.006) Indoor carbon dioxide in the classrooms was low (range 380-720 ppm), temperature was 25-30 °C and relative air humidity 70-88%. Total fungal DNA in vacuumed dust was associated with shorter SBUT (4 s shorter per 105 target copies per gram dust; p = 0.04) and NIBUT (4 s shorter per 105 target copies per gram dust; p < 0.001). Aspergillus/Penicillium DNA was associated with shorter NIBUT (5 s shorter per 105 target copies per gram dust; p = 0.01).ConclusionFungal contamination in schools in a tropical country can be a risk factor for impaired tear film stability among students.