T Singh

NIOH, University of Cape Town, University of the Witwatersrand

Project Summary:

This study proposes to explore the associations between work related asthma and endotoxin exposure from dental unit waterline contamination in dental workers from academic institutions in South Africa.
Dental unit waterline contamination has become a concern as biofilms increase the numbers of free floating microorganisms e.g. gram negative bacteria exiting the waterlines. These bacteria not only cause disease by itself but also produces endotoxins, which can elicit a non-allergic neutrophilic inflammatory response. Studies have shown that approximately 50% of asthma cases are attributable to eosinophilic airway inflammation. It is hypothesised that a major proportion of asthma is based on neutrophilic airway inflammation, possibly triggered by environmental exposure to bacterial endotoxin.

Environmental sampling methods will be used to establish the levels of endotoxin in ambient air and dental unit waterlines. In addition, serum levels of endotoxin in dental workers and students in these institutions will be determined. Levels of biological markers, eosinophilic cationic protein (ECP) and myeloperoxidase (MPO) will be determined to establish whether the response in neutrophilic or eosinophilic. Health questionnaires and lung function assessments will be used to measure the prevalence of work-related asthma amongst these individuals.
The study will then seek to characterise the relationship between current exposure to endotoxins and work-related asthma symptoms while controlling for potential confounders such as age, gender and smoking. Finally, data will be used to increase the understanding of the contribution of neutrophilic asthma as a result of exposure to endotoxin as opposed to eosinophilic asthma in work-related asthma amongst dental workers.

Contact Person:
Dr. T. Singh