Triclosan, an antibacterial chemical found in toothpaste and other products, can contribute to an increased risk of allergy development in children according to the Norwegian Environment and Childhood Asthma Study. Similar results are reported in the U.S.
Triclosan has been in use for decades, but was recently associated with allergies in children in an American study, the National Health and Nutrition Examination Survey (NHANES). The new Norwegian study found similar associations between allergies and triclosan levels measured in children's urine.
The study found that triclosan levels measured in urine were associated with elevated levels of Immunoglobulin E (IgE) and rhinitis (blocked nose/hay fever) in 10-year-olds.
Six hundred twenty-three urine samples were collected and measured at the Centers for Disease Control and Prevention (CDC). Approximately 50 percent of the Norwegian children had detectable levels of triclosan, while 80 percent of American children had measurable levels. The children had approximately the same amount of triclosan exposure.
Triclosan can change the bacterial flora on the skin, in the mouth and in the intestines. A change in the bacterial composition of "good" bacteria can cause an increased risk of developing allergies (hygiene hypothesis). Therefore, increased use of triclosan and antibacterial products has generally been associated with an increased incidence of allergies.
For many years, health authorities in Norway have called for a reduction in the use of antibacterial products to prevent the development of resistant bacteria.
In a study of triclosan use in Norway in 2001, it was found that 85 percent of the total amount of triclosan came from cosmetic products, of which 75 percent were toothpaste. Since this study, triclosan has been removed from a variety of products.
The extent to which Norwegian children are exposed to triclosan is today uncertain. In the U.S., where there is annual sampling and monitoring of chemical exposure, there is little evidence that exposure to triclosan is being reduced.
The triclosan study is a collaboration between the Norwegian Institute of Public Health, Oslo University Hospital and the National Institute of Health Sciences (NIEHS) in the USA, where Randi Bertelsen is currently a guest researcher. The project is partly funded by the Research Council of Norway's programme for Environmental Exposures and Health Outcomes.
Reference: Bertelsen RJ, Longnecker MP, Løvik M, Calafat AM, Carlsen K-H, London SJ, Lødrup Carlsen KC. Triclosan exposure and allergic sensitization in Norwegian children. Allergy 2012; DOI: 10.1111/all.12058.