Tanning Salon Exposure Can Lead to Skin CancerMay 29, 2001
For years, having a tan has been synonymous with health and vitality. And for those who feared the damage done to the skin by outdoor ultraviolet (UV) exposure, indoor tanning was touted as a safe alternative. However, a recent study shows that the UV exposure received from a tanning bed may be just as harmful to the skin as outdoor sun exposure, leading to the same molecular alterations believed to be necessary for the development of skin cancer.
"On an average day in the United States, more than 1 million people invest both time and money to visit tanning salons, despite studies which have found an increased incidence of melanoma, the most deadly form of skin cancer, in those who visit indoor tanning salons," stated dermatologist S. Elizabeth Whitmore, MD, co-author of "Tanning Salon Exposure and Molecular Alterations" published in the May 2001 issue of the Journal of the American Academy of Dermatology. "This is the first study to examine and show that similar molecular damage occurs with indoor UV exposure, as found with outdoor UV exposure."
The study exposed individuals to a series of ten full-body tanning salon treatments over a two-week period. Only a small part of the buttocks was covered to provide a control skin sample. During the final exposure, one-half of the skin on the buttocks was uncovered, thereby providing an area for examination after a single UV exposure.
The indoor tanning light source used in the study emitted 95 percent UVA, the type of UV radiation that penetrates more deeply into the skin. The remaining 5 percent of light was UVB, the type of UV radiation that affects the epidermis, the uppermost skin layer, and is often associated with sunburn. "Indoor tanning uses UVA radiation, which leads some in the industry to claim that indoor tanning is a safe alternative to outdoor tanning," said Dr. Whitmore, Associate Professor of Dermatology, Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD. "However, most salons bulbs still provide a significant amount of UVB radiation, in addition to UVA. Both types of ultraviolet light, whether from sunlight or indoor tanning light, cause various types of damage in the skin that may lead to skin cancer and should be avoided."
Skin biopsies, as well as blood samples, were taken after a single UV exposure and after the final UV exposure to determine the molecular alterations in the skin and blood. Specifically, the study analyzed the amount of cyclobutane pyrimidine dimer (CPD), and p53 protein in the skin and blood. CPD is the most common type of DNA damage caused by UV radiation, which if left un-repaired, results in the skin mutations found in skin cancer. p53 is a protein which allows cells to slow down their reproduction process so that damage from UV radiation can be repaired.
The study found that relative to the unexposed control skin, there was a significant increase in CPD in the skin biopsies taken after the last UV exposure. In addition, the quantity of CPD in the skin after just one exposure was similar to the quantity in the skin that received all ten exposures. Also, within 24 hours of the first UV exposure, p53 protein was present in all layers of the epidermis.
"The increased presence p53 protein in the skin signifies that the body is responding to the cell damage, or the CPD, due to UV exposure," said Dr. Whitmore. "And though the body is trying to repair the damage, there is the risk of a mistake in the repair process which increases as the number of altered cells increases. If there is a 'miss' in the cell repair process, subsequent replication of the altered cell yields a clone of abnormal cells which may eventually appear as a skin cancer."
Regulation of the $2 billion tanning salon industry in the United States is limited, with only 21 states having regulatory laws in place. The Centers for Disease Control and Prevention reports an estimated 700 emergency department visits per year related to tanning salon exposure.
"There is no such thing as a safe tan," said Dr. Whitmore. "A suntan is the skin's response to an injury and every time you tan you accumulate damage to the skin, as well as accelerating the aging process and increasing your risk for skin cancer. As long as indoor tanning for cosmetic effects is permitted in this country, there needs to be increased educational efforts informing the public of the risks of this type of tanning."
Unless and until the Food and Drug Administration (FDA) bans the sale and use of tanning equipment for non-medical purposes, the AAD supports the following requirements for indoor tanning facilities, including:
-- A warning statement defining potential hazards and consequences of exposure to UVA should be signed by each patron.
-- No minor should be permitted to use a tanning bed without written consent of a parent or guardian.
-- No person or facility should advertise the use of any UVA or UVB tanning device using wording such as "safe," "safe tanning," "no harmful rays," "no adverse effect," or similar wording or concepts.
This year, more than one million new cases of skin cancer will be diagnosed in the United States. An estimated 51,400 of those will be diagnosed with melanoma, the deadliest form of skin cancer. Approximately, 7,800 people will die from melanoma; 5,000 men and 2,800 women. However, skin cancer is highly treatable, especially if it is caught early and while it is still localized.
The American Academy of Dermatology, founded in 1938, is the largest, most influential, and most representative of all dermatologic associations. With a membership of over 13,000 dermatologists worldwide, the Academy is committed to: advancing the science and art of medicine and surgery related to the skin; advocating high standards in clinical practice, education, and research in dermatology; supporting and enhancing patient care; and promoting a lifetime of healthier skin, hair and nails.