“A Call to Action to Prevent Skin Cancer” by acting Surgeon General Dr. Boris Lushniak recently pointed out that the use of UV tanning beds are “strongly associated with increased skin cancer risk.” In support of Lushniak’s claim, an opinion from the University of Colorado Cancer Center was recently published in the American Journal of Preventive Medicine demonstrating that the use of UV tanning beds not only increases skin cancer risk, but also meets equivalent criteria as smoking as a cause of cancer. The correlation is prompting calls for the acting Surgeon General to launch a public health initiative against the use of tanning beds similar to the ongoing non-smoking campaign in the U.S.
“In 1964 when the Surgeon General finally reported that smoking causes lung cancer, awareness and policy followed. Smoking rates declined and lung cancer rates have too. It’s time for the Surgeon General to say the same thing about UV tanning,” said Robert P. Dellavalle, MD, PhD, MSPH, investigator at the CU Cancer Center, associate professor of dermatology at the University of Colorado School of Medicine, and the study’s senior author in a news release.
There are nine criteria to determine a causal relationship in disease. This was first developed in 1965 by Sir Austin Bradford Hill in the context of smoking and lung cancer. Smoking and UV tanning both meet eight of the nine criteria, as follows:
- Strength of Association: According to Dellavalle and colleagues, results from large population studies have shown that the risk of developing skin cancer is approximately 16% more likely in people who have used a UV tanning bed. The association between smoking and lung cancer has reached a 35% increased risk rate. Epidemiologically, the 16% increased risk of skin cancer in people who use UV tanning remains robust.
- Consistency of Association: The association between UV tanning and skin cancer has been established in populations from different backgrounds and nationalities. Dellavalle and colleagues highlight that the link between UV tanning and skin cancer is not restricted to a specific population or nationality. The association seems to be constant in all studies.
- Specificity: The relationship between UV radiation exposure and the development of skin cancer has been accurately established.
- Temporality: Every time a person uses a UV tanning bed it is increasing the likelihood of developing skin cancer.
- Biological Gradient: The more one uses tanning beds the more prone one is to develop skin cancer. As Dellavalle mentioned, “Each additional tanning bed session per year confers a 1.8 percent increase in melanoma risk.”
- Plausibility: Is it possible that UV tanning causes skin cancer? The answer is yes, as UV rays in tanning beds can penetrate the epidermal layer, inducing alterations in the DNA usually associated with cancer formation.
- Coherence: There is consistency on the data from population studies and laboratory experiments, as both sources reached similar conclusion.
- Experiment: In animal models, researchers have tested UV radiation as a direct cause of skin cancer. However, it is unethical to incite people to tan to prove if tanning causes skin cancer. According to Dellavalle, the lack of capability to assess results of UV tanning on cancer in a randomized control study is “a primary advantage for the tanning industry, which claims that there is lack of true science behind cancer-causing claims.”
- Analogy: Higher rates of skin cancer are usually seen in people with a skin type that burns easily.
As Dellavalle mentioned, the majority of cancers are usually seen as consequence of random, genetic alterations that allow cells to become malignant “But skin cancer and lung cancer are preventable types of cancer – reduce smoking and you reduce lung cancer; reduce UV exposure and you reduce skin cancer,” he said. “It’s much easier to help people understand that indoor tanning causes cancer than it is to message something more convoluted about ‘association’. Tanning beds cause skin cancer. It is time to now more openly announce this causality.”