This article is more than 5 years old. Information may no longer be current.
Addressing mixed messages about sunscreen, exposure and melanoma
As of 2006, one in every 53 people born in the United States will at some point be diagnosed with melanoma, according to the National Cancer Institute. This is a substantially higher risk than ever before.
Since the National Cancer Institute’s SEER database started tracking cancer incidence in 1975, melanoma rates have risen from under eight cases per 100,000 individuals to over 21. It is within this context that efforts to understand the public’s sun exposure habits, awareness of skin cancer risk and sunscreen use have increased in recent years.
|
Photo courtesy of Suzanne Camarata |
Understanding why melanoma rates may be rising is difficult given the long lag time believed to exist between sun exposure and sun-caused melanoma diagnosis. “If [melanoma] is most common in a 50-year-old today, then we have to ask where that 50-year-old was 35 years ago,” said Alan Geller, MPH, RN, a senior research scientist and deputy director of the division of public health practice at Harvard School of Public Health. “I think it is important to try and get a sense culturally of all of those changes.”
If some of those questions can be answered, it may help tailor modern public health campaigns to the individuals most at need. Understanding how people act, how they use sunscreen or other sun protection and how much sun exposure can be tolerated are important pieces of that puzzle.
Substantial research has been dedicated to skin cancer risk behavior, and much of the literature points toward underuse of sun protection. In one study published last year in the American Journal of Preventive Medicine, risk behaviors of more than 28,235 adults participating in the National Health Interview Survey were assessed. The majority of people in the study reported engaging in at least two skin cancer risk behaviors: infrequent use of sun-protective clothing, staying in the sun when outside on a sunny day, infrequent use of sunscreen with a sun protection factor (SPF) of at least 15, use of indoor tanning devices and a sunburn in the past year.
“Our study suggests that, since many people engage in more than one skin cancer risk behavior, there is a need to use a comprehensive approach to skin cancer risk prevention,” said Elliot Coups, PhD, an associate member in the Cancer Prevention and Control Program at Fox Chase Cancer Center in Pennsylvania and lead author on the study.
|
|
“We need to approach the issue of skin cancer prevention from as many perspectives as possible, including multimedia public health campaigns as well as assessment and intervention efforts carried out by health care providers. It’s important to remember that people are not all the same and that what motivates one person to change behavior may not motivate another,” he said.
Coups added that the age-stratified study highlighted the fact that some subpopulations may be in greater need of aggressive public education programs than others. For example, 30% of the 5,370 participants aged 18 to 29 had three risk behaviors and 13.5% had four; both numbers were greater than any other age group in the study.
The problems among the younger population were also highlighted in Geller’s 2002 study published in Pediatrics. That study involved more than 10,000 people aged 12 to 18, children of participants in the Nurses’ Health Study. Eighty-three percent reported having at least one sunburn during the previous summer, and 36% had three or more. Girls were more likely than boys to use sunscreen (40% prevalence vs. 26.4%).
The Centers for Disease Control also monitors sunburn prevalence. In 2007 it reported that the estimated rate of sunburn among all U.S. adults rose from 31.8% in 1999 to 33.7% in 2004. Men were consistently more likely to burn than women, and there were surprisingly high rates of sunburn among ethnic groups “traditionally considered at lower risk for sunburn or skin cancer.”
Reports from elsewhere in the world indicate similarly lax attention to sun protection and high rates of sunburn. In Australia, which Barbara Gilchrest, MD, said is “ahead of us” in terms of public health messaging about sunscreen and skin cancer, adolescents were found to have generally low compliance with sun protection methods and burned more frequently than adults (25% vs. 18%). Gilchrest is a professor of dermatology at Boston University.
Melanoma epidemiology
This generally poor level of awareness and sun protective behavior may play a role in increasing rates of melanoma, but the correlation is difficult to make because of the long lag time between sun exposure and development of malignancies. If risky behavior is increasing today, melanoma rates may continue to rise far into the future.
The current epidemiology of melanoma, which is more strongly related to decades-old behavior, shows an increasing prevalence. According to a survey of the disease published in Dermatology Clinics in 2009, there were 62,480 new cases of melanoma and 8,428 deaths in 2008. In the paper researchers, led by Marianne Berwick, PhD, MPH, of the University of New Mexico in Albuquerque, said that some of the increase in prevalence can be traced to the fact that “we are certainly looking harder for melanoma as evidenced by the increasing rates of biopsy, and we are finding lesions today that 20 years ago would never have been called melanoma.”
A further complicating issue is that the exact mechanisms by which sun exposure help cause melanoma are poorly understood and also seem counterintuitive to the lay public. For example, Gilchrest said that chronic sun exposure of “a lobsterman or a construction worker” does not appear to affect melanoma rates (and some studies even indicate a protective effect), while intermittent exposure — such as people who work indoors but take vacations to sunny areas — appears to be the primary sun-related melanoma risk factor.
Screen, and public health messaging
When it comes to public health campaigns aimed at reducing sun risk behaviors and melanoma risk, a number of issues complicate the message. Perhaps most important is the lag time between exposure and malignancy development.
“No teenager ever thinks they’re going to get skin cancer,” Gilchrest said. “I think we in the dermatology community — and the media — [should] emphasize very strongly the skin cancer problem.”
Also, sunscreen is not the easiest product to convince people to use. “Tanning is often a social activity, and using sunscreen is sometimes viewed as ‘uncool,’” Coups said.
Even when people do use it, they do not use it as intended. The SPF of a sunscreen is determined based on application of 2 mg/cm2 of the product, an amount which Gilchrest says is unrealistic in general use. “Essentially, nobody puts that much on,” she said. “It feels like you’re just globbing the stuff on and people don’t use it that way.”
Geller thinks that wording of sun protection products, like the SPF, probably are not well understood in the general public, leading to misuse and inappropriate time spent in the sun. However, he said that understanding SPF is far less important than use of the product.
“I don’t lose too much sleep over the difference between SPF 15 and 30,” he said. “Where I lose sleep is how well people apply the product they have, whether it is 15 or 30.”
Interestingly, some studies — notably by Philippe Autier, MD, of the International Agency for Research on Cancer in Lyon, France — have found that the use of sunscreen or higher SPF sunscreen products actually leads to more time in the sun and a higher prevalence of sunburn. However, subsequent examinations of the same question have refuted the idea, and there is still some question about how sunscreens affect behavior. Despite this, there is no question that recreational sunbathing is a melanoma risk-elevating behavior.
The vitamin D issue
In recent years, another complicating factor has emerged that is making public health campaigning difficult: vitamin D. As the mainstream press reports on research about the benefits of higher circulating vitamin D levels, sun protection practices may be declining as a result.
A study published in the International Journal of Cancer earlier this year surveyed 2,001 Queensland, Australia, residents about sun protection and attitudes about vitamin D. Thirty-two percent of the cohort believed that a fair-skinned adult required at least 30 minutes of summer sun exposure per day to maintain sufficient vitamin D levels, and 31% thought that children need the same amount. Most research indicates that the actual number is substantially lower, with estimates placing the optimal intake between five and 30 minutes only twice per week.
In the same study, 21% of adults and 14% of children reported reductions in sun protective behavior because of the desire to maintain vitamin D levels. “I think if we can separate the issue of how much vitamin D from how much you should protect yourself in the sun. If you can separate those two issues, there’s no problem,” Gilchrest said, adding that vitamin D can easily be obtained through dietary supplementation.
Even though adequate vitamin D can be obtained in a dietary supplement, the indoor tanning industry has picked up the vitamin D message as a selling point for its services. “It is being promulgated in part by representatives of the indoor tanning industry, who are very pleased that people are quite confused about this issue,” Gilchrest said.
The success of campaigns connecting vitamin D with sun exposure is apparent simply from the nickname “sunshine vitamin.” Information on websites like TanningTruth.com suggests that everyone be exposed to 20 to 30 minutes of sun every day and discounts the need to use sunscreen on a regular basis.
Opponents of indoor tanning note that it is a $6 billion per year industry with obvious motives, while the tanning advocates fight back that sunscreen is itself a multibillion dollar per year industry with its own financial goals. In addition, the metabolic pathways for cytochrome p450 anabolism and catabolism of vitamin D have only recently been clarified, and these have not yet been factored into the overall equation. It is no surprise that the messages reaching the public through the press or advertising contain mixed signals.
Fixing the public health campaigns
All of these confounding issues add up to a very difficult public health problem. Campaigns in the past have focused on the risk of skin cancer with extended sun exposure, but the lag time and perceived benefits make that a difficult sell, especially to younger people who appear to engage in riskier activities anyway.
“Like many other health-related behaviors, the immediate rewards of the unhealthy behavior may seem more salient to people than the uncertain benefits of the healthy behavior for the distant future,” Coups told HemOnc Today.
Because of that challenge, tailored messages and a less all-or-nothing approach could be useful in helping bring down risk behaviors and skin cancer risk. “Rather than telling everyone to completely avoid the sun at all times, we can also advise people on effective prevention strategies… if they are going to be outside on a sunny day,” Coups said. – by Dave Levitan
For more information:
- Coups EJ. Am J Prev Med. 2008;34:87-93.
- Geller AC. Pediatrics. 2002;1009-1014.
- Centers for Disease Control. MMWR. Sunburn prevalence among adults. 2007;56:524-528. Accessed at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5621a2.htm
- Dobbinson S. J Am Acad Dermatol. 2008;59:602-614.
- Berwick M. Dermatol Clin. 2009;27:205-214.
- Autier P. Int J Cancer. 2007;121:1-5.
- Youl PH. Int J Cancer. 2009;124:1963-1970.