New research suggests that tanning may not only increase the risk of skin cancer, but also appears to be addictive, leading to additional concerns about the popular practice, especially among teens and young adults.
In a study published by the medical journal Cell on June 19, researchers found repetitive exposure to ultraviolet (UV) light, either from the sun or indoor tanning beds, can result in physical dependence and addiction.
As part of the research, laboratory mice were exposed to UV light every day for six hours. The backs of the mice were shaved to allow the light to cause tanning, without burning the mice.
UV rays stimulate the production of endorphins, the same hormones stimulated by vigorous exercise. While mostly known as the “feel-good” hormones, the endorphins function through the same biological pathway as addictive opiate drugs, like heroin and morphine.
The endorphins turn on opiate-related receptors the same way painkillers or heroin would, causing an addictive response to tanning.
The study used lab mice, but researchers say the results are also applicable to people because the biological response of skin to UV radiation in mice is similar to that of a humans.
During the study, the mice were exposed for six weeks, but researchers found bloodstream endorphin levels rose within only one week of UV exposure. The mice also exhibited withdrawal symptoms, including tremors, shaking and teeth chattering, after being treated with a drug that blocked the endorphin activity.
UV light is a known carcinogen and has been linked to the development of skin cancer. Regular tanning, whether indoor or outdoor, raises the risk of skin cancer, and researchers indicate that their findings mean it is also highly addictive.
Dr. David Fisher from the Massachusetts General Hospital and Harvard Medical School said the addictive nature of UV exposure may contribute to the relentless rise in skin cancer incident in humans.
Researchers said UV-related skin cancer should be preventable simply by reducing exposure, but the addictive qualities of the process may interfere, causing many to seek a golden tan at any cost.
The study adds to the mounting concerns about the risks associated with indoor tanning beds, which have been linked to the development of deadly skin cancer melanoma.
Last year the FDA proposed to recategorize tanning beds as a moderately dangerous medical device due to the risk of cancer. The new labels would require warnings advising teens not to use the devices.
In addition, the rule categorizes the beds from a class I, low risk, device, to a class II, moderate risk, device.
The FDA issued new regulations for indoor tanning in May 2014. The new rules went above the earlier recommendation, placing a black box warning on tanning beds and tanning booths.
The changes add a warning against the use of tanning lamps in individuals under the age of 18. It also reclassifies tanning beds to class II products, like the initial proposal recommended.
Melanoma skin cancer rates have risen for the last 30 years with 76,000 new cases each year and nearly 10,000 deaths projected for 2014, according to the American Cancer Society.
Cumulative damage from UV radiation, indoor or outdoor, may cause cancer; but can also cause premature skin aging as wrinkles, lax skin and brown spots.