The association of tanning with risk of skin cancer has been known for quite some time. However, scientists are now uncovering observations to suggest that tanning may also be addictive - similar to drug addiction!
Before we go into the details of how tanning causes addiction, here is a review of tanning and its adverse effects.
A tan is the skin's reaction to exposure to UV rays i.e. it is our body's protective response to injury. UV radiation is of 2 types:
- UV-B: These type of UV rays penetrate the top layers of the skin and cause sunburns. These rays are predominant in sunlight
- UV-A: These UV rays penetrate deeper into the skin and are associated with allergic skin reactions. These rays are predominant in indoor tanning salons
Both UV-A and UV-B cause skin cancer. However, since UV-A can penetrate deeper, the skin cancers caused by these rays are generally more dangerous as they can metastasize (break off & go to other parts of the body). Furthermore, as there is minimal sunburn, there is little disincentive to stop using tanning parlors thereby increasing the risk of skin cancer several fold. This is what makes indoor tanning so dangerous.
Now for some facts:
- Tanning beds are used by about 10% of Americans per year
- From 1992 to 2004, new diagnoses of melanoma in women 15-39 increased by 2.7%
- Incidence of thicker melanoma (>1 mm) has increased
- Regional & distant metastasis increased at estimated annual rate of 9.2%
- People who first used indoor tanning before 35 years of age, relative risk of developing melanoma was 1.75
- Indoor tanning was associated with relative risk of 2.25 for development of squamous cell carcinoma (which in a small number of patients can metastasize
- WHO has classified Tanning beds as Group 1 Carcinogen
- FDA classifies tanning beds Class 1 medical devices - the same class as tongue depressors and adhesive bandages!
Other risks of tanning:
- Premature aging
- Immune suppression leaving the body vulnerable to various diseases
- Eye damage
- Allergic reactions
So how does tanning cause addiction:
UV rays up regulate genes to synthesize a protein called pro-opiomelanocortin. This protein is then split by the body into 2 parts:
- Melanocyte stimulating hormone: which increases the synthesis of melanin in skin cells leading to a tan
- Beta-endorphin: which is an endogenous opioid like morphine & heroin which may be responsible for addiction.
In fact, it has been shown that people can differentiate between UV radiating and sham devices. Furthermore, injecting an opiate receptor blocker in people undergoing regular tanning induces a withdrawal reaction (although mild) similar to some one who abuses heroin!