New research published in Acta Oncologica has found that routine dental X-rays can increase your risk of thyroid cancer. Currently, exposure to high dose radiation is the only established cause of thyroid cancer and this type of cancer has been rising. In 1975 the rate of thyroid cancer was 1.4 per 100,000 and by 2006, this had risen to 2.9 per 100,000.
Three hundred and thirteen patients in Kuwait were studied, in part because dental treatment is free in Kuwait so citizens have access to regular dental X-rays. The researchers found that:
"Exposure to dental X-rays was significantly associated with an increased risk of thyroid cancer. These findings, based on self-report by cases/controls, provide some support to the hypothesis that exposure to dental X-rays, particularly multiple exposures, may be associated with an increased risk of thyroid cancer.”
Researchers suggest that patients not have X-rays for non-urgent reasons, such as a routine dental X-ray when joining a new dental office. Dr. Anjum Memon, the lead study author, said “Our study highlights the concern that like chest (or other upper-body) X-rays, dental X-rays should be prescribed when the patient has a specific clinical need, and not as part of routine check-up or when registering with a dentist.”
Dentists, however, have criticized the study, saying that Kuwaitis have a higher rate of thyroid cancer anyway, which could have biased the study results. However, one of the reasons they have a higher rate may be because of the free access to dental care, which in many other countries is charged for and therefore out of the regular reach of many.
An earlier study published in the Lancet and reported by BBC News found that hospital X-rays, dental X-rays and diagnostic scanning such as CT scans, were causing 700 cancers per year in the United Kingdom. Researchers from Oxford University believe that 0.6 percent of the UK cancer risk is from X-rays.
In the United States, around 0.9 percent of cancers are due to X-rays, in Germany the rate is 1.3 percent and in Japan it’s a huge 2.9 percent which accounts for 7,500 cancers a year.