Defining Safety: Tanning, Sunscreens, Vitamin D Supplements and Botox

The recent firestorm of anti-tanning propaganda featuring the false and misleading claim that “there is no such thing as a safe tan” caused us to wonder how tanning compares to sunscreens, vitamin D supplements and Botox injections with regard to safety. But, in order to make this comparison, we must first define the words “safe” and “tan.”

• “Safe” can be defined as: an activity that is free from all injury or risk; an activity that involves little or no risk; or, an activity where the benefits outweigh the absolute risks involved.
• “Tan” can be defined as: photo-protective facultative pigmentation that develops when the skin is exposed (not overexposed or underexposed) to ultraviolet light.

Those who oppose the indoor-tanning industry choose, for biased and vested-interest reasons, to frame the discussion of tanning in terms of the first definition of “safe,” i.e., that tanning is an activity that is not free from all injury or risk. They do this even though they know — or reasonably should know — that the second and third definitions of “safe” are more appropriate with regard to tanning in the carefully controlled environment of a professional tanning salon. (Translation: Tanning is an activity that involves little or no risk when appropriate measures are taken, and indoor tanning is an activity where the benefits significantly outweigh the minimal and manageable absolute risks involved.)

Mother Nature has endowed people with the ability to effectively protect the DNA in our skin cells from overexposure to UVR through tanning; to say or imply that this normal and natural process is a “sign of skin damage” is another example of false and misleading anti-tanning propaganda.

That said, the next thing to examine is the critically important difference between relative risk and absolute risk.

Health statistics usually are presented in terms of relative risk (RR) for the simple reason that larger RR numbers are more likely to capture people’s attention. However, showing a 100-percent increase in RR can be misleading when the “base rate” of the disease in question is left out. When the base rate of the disease in question is disclosed, the absolute risk (AR) of the disease can be determined. Though AR information (i.e., “one in 7,000”) is more informative, usually it is omitted because it is easier to “spin” RR values (i.e., a 100-percent increase).

Case in point: A British report showed that oral-contraceptive pills posed a 100-percent increase in the relative risk of developing a potentially fatal blood clot. This incomplete and misleading information led to a mass panic among women who opted to stop using this form of birth control. As a result, there were 13,000 more abortions in England and Wales in the year following the report—which contained only the RR information, i.e., a 100-percent increase in the potential for developing a blood clot. Had the public been informed that the absolute risk involved with taking the birth-control pill only increased the possibility of developing a potentially fatal blood clot from one in 7,000 women to two in 7,000 women, the public probably would not have overreacted in a such a way.

The common use of RR values over AR values is explored in the article “Ratio Measures in Leading Medical Journals: Structured Review of Accessibility of Underlying Absolute Risks” by Lisa Schwartz, Steve Woloshin, Evan Dvorin and Gilbert Welch. Published in the British Medical Journal in 2006, the article is based on the fact that the authors found 68-percent of the articles they surveyed failed to report the underlying absolute risk. In summary, the authors noted that, “Absolute risks are often not easily accessible in articles reporting ratio measurements and sometimes are missing altogether—this lack of accessibility can easily exaggerate readers’ perceptions of risk.”

The same is true for articles written by those who oppose tanning. Indeed, every single anti-tanning article in our library—of more than 2,500 articles—provides only the misleading relative-risk values. Why? Because if they provided the absolute-risk values, their anti-tanning propaganda would be seen for what it is—propaganda.