Epidemiology

Asthma pumps could cause cavities

The risk of developing cavities by the age of seven could be up to 62% higher for children with asthma who use inhalers (Ventolin, Flovent, etc.) than for other children. At least, that’s the conclusion that emerged from a study conducted in Denmark in 2004. However, the sampling was small – only about 100 children – making the conclusions hard to accept from an epidemiological viewpoint.  “Various studies have been conducted in the U.S. and Europe on this, but they all have problems in terms of methodology,” explains Régis Blais, a professor in the Department of Health-Care Administration and a researcher with the Groupe de recherche interdisciplinaire en santé (GRIS) at the Université de Montréal. “This time, we want to be very clear about it.”

Professor Blais, who heads the largest study to date on the links between inhalers and cavities in children, was given access to data on several thousand asthmatic children up to the age of nine. Based on the medical files of the Régie de l’assurance maladie du Québec (RAMQ, or Quebec Health Insurance Board), the researcher will be able to measure the link between cavities and the use of aerosol medication. He expects to have results by the end of 2006.

The public nature of the Quebec health-care system makes it possible to collect this type of data and analyze both prescription medications sold as part of the public drug insurance plan and the free dental care provided by the RAMQ. The study will not involve any dental or medical examinations, as it is based on data that have already been collated: name of medication, dose, age of patient, how long the prescription is taken, and so on. The team of researchers affiliated with GRIS includes dentist and epidemiologist Jean-Marc Brodeur, pharmacy professor Claudine Laurier, statistician Karen Leffondré of the Université de Montréal, and dentist and researcher Christophe Bedos of McGill University.

The connection between aerosol medication and cavities can be explained by three factors. First of all,  Ventolin, Flovent, and company may cause a reduced flow of saliva in regular users – and saliva is a highly effective natural tooth cleaner. Second, pharmaceutical studies have shown that pH in the mouth can be changed by medication, which can change the acidity of the saliva and in turn affect cavities. Third, the dry powder that transports the medication into the lungs (e.g. fluticasone) contains lactose, which could also affect the teeth. “But these are only hypotheses,” says the researcher. “Our study is not designed to confirm the mechanism for the increased number of cavities, if that proves to be the case.” 

Their conclusions could help target campaigns that promote dental health more effectively. “If we find a positive correlation, perhaps we should suggest that the pharmaceutical companies find a new lactose-free component to use in medication,” suggests Blais. “We could also recommend that young asthmatics be followed more closely by their dentists, or that they follow specific dental hygiene practices to prevent cavities from developing.”