The Skinny on Sunscreen

July 6, 2001

By Michael Jessen

Two words - Sun's out!

After a winter bustling with low cloud and a spring drenched with gentle rain, those two words warm the hearts and bodies of almost every Kootenay resident.

Ah, but there's the rub. With the thinning of the ozone layer the sun's ultraviolet (UV) rays are something to chafe about. Yet who wants to be a shady character when you're just trying to look sun-sational.

The warm feeling of sunshine on skin for a short period (15 to 20 minutes) of time every day is a good thing. It helps the skin make Vitamin D that is essential for the assimilation of calcium and other minerals.

But the sky's fireball -- which sustains all life on Earth -- is also the main cause of skin cancer, the most common type of cancer in Canada. In 2001, 70,000 Canadians will be diagnosed with skin cancer. Over the past 10 years, the number of cases of skin cancer in Canada has increased by over 60%. Skin cancer is also the second most common cancer among women.

According to the Canadian Dermatology Association (CDA) www.dermatology.ca/, over 50% of Canadians don't use any sun protection, even though this is the main risk factor associated with the development of skin cancer and premature skin aging. Those who do use sunscreen often don't use it properly.

Annie Berthold-Bond, an environmental author, even questions whether sunscreens themselves have been contributing to the worldwide epidemic of skin cancer.

"Until recently, sunscreens have protected only against UVB rays, not UVA rays," Berthold-Bond writes in her latest book Better Basics for the Home: Simple Solutions for Less Toxic Living.

"UVB rays cause sunburn, and if you screen them you might stay in the sun longer, overexposing yourself unprotected to UVA rays," she adds. "UVA rays make up 90 to 95 percent of total UV ray exposure, and overexposure is thought to be one cause of the skin cancer epidemic."

Dermatologist Jason Rivers agrees and retains a nagging worry that some of the plethora of products on drugstore shelves may still offer little UVA protection.

"There is no standardized test for measuring UVA protection in a sunblock," says Rivers, who is a regional director of the CDA's sun awareness campaign. He suggests that consumers look for the active ingredients Parsol 1789, titanium dioxide, or zinc oxide.

The CDA logo on a sunscreen indicates that the product has been tested and fulfills the criteria for a safe sunscreen as defined by the organization. These criteria include having a UVB sun protection factor (SPF) of at least 15 and a broad spectrum UVA block. The association prefers that the product be fragrance-free and it must be non-comedogenic (not likely to produce or aggravate acne). Sixty-five recognized sunscreens and other products containing recognized sunscreens can be found on the CDA web site at www.dermatologie.ca/english/sun/index.html.

While the scientific debate simmers about whether current sunscreens provide adequate protection, the U.S. Food and Drug Administration has delayed until December 2002 the implementation of a so-called final monograph on sunscreens. This monograph is a kind of recipe book covering acceptable ingredients, doses, formulations, and labeling.

Since SPF numbers are developed in an indoor laboratory under unrealistic wearing conditions, sweat, dirt, elevation, and a number of other factors can render an SPF of 26 quickly into an SPF of 15. The SPF numbers are also generated by using a two millimetre thick layer of sunscreen, roughly the equivalent of 35 ml or a little over an ounce. Therefore a 120-ml bottle should last you four applications.

"Most people use half to a quarter of what they should," says dermatologist Rivers, "turning a perfectly acceptable SPF 15 into a feeble SPF 2 or 4."

And don't count on a sun tan to protect you either says Health Canada. A tan actually indicates that your skin has already been damaged and it only offers an SPF of about 4.

So have fun in the sun, but remember it is cool to cover up.

ONE SMALL STEP - The CDA recommends a series of actions to avoid getting sunburn and putting yourself at risk of a future skin cancer. Wherever possible, avoid the sun between 11 a.m. and 4 p.m. when UV levels are highest. Use a broad-spectrum sunscreen (UVA and UVB) with at least an SPF 15, or higher. Wear a hat with a 3-inch brim, sunglasses, and protective clothing to cover your upper back, arms, and legs.

RESOURCES - Make it a daily habit to check the UV index in your area, available on various radio stations, The Weather Network at www.theweathernetwork.com/index_can.htm, or the Environment Canada web site at http://weatheroffice.ec.gc.ca/. The following descriptions are usually associated with various values of the UV index: Low UV exposure - 1 and 2; Moderate exposure - 3 and 4; High exposure - 5 and 6; Very high exposure - 7 and 8; Extreme exposure - greater than 9. Annie Berthold-Bond has a recipe for homemade sunscreen in her latest book. It is also on her web site at http://betterbasics.com/askview.php3?view=bodycare/homemade_UVA_and_UVB_sunblock. The U.S.-based National Consumers League has helpful information about protecting your eyes from the sun at www.nclnet.org/eyepub.htm.

UPDATE FROM ENVIRONMENTAL NEWS NETWORK, AUGUST 28,2001

Ozone depletion increases skin cancer risk By Tom Fry Tuesday, August 28, 2001

In an ironic twist, we are no longer simply loving the environment to death. Now it seems we are risking death to love the environment. Around the world, incidences of skin cancer are skyrocketing. Scientists and researchers largely attribute this to a single cause: our love of being outside.

However, a long recognized and much studied environmental factor may significantly influence this public health quandary. In the last decade, dozens of researchers have produced scores of reports relating stratospheric ozone depletion to human health concerns. At issue is the amount of ultraviolet B light that penetrates through the atmosphere in areas of low ozone.

Ultraviolet B or UVB is the particular range of the invisible light spectrum from 280 to 315 nanometers. UVB are known as the "burning" rays and are the most common cause of sunburns.

Traditionally, only a small percentage of the Sun's UVB reaches the Earth's surface. The bulk is absorbed in the atmosphere. However, research has indicated that in areas of lower than normal ozone, UV intensity increases. In the December 2000 issue of Photochemical Photobiology, a study by I. Sobolev of Chemical and Polymer Technology Inc. showed a variant 236 percent increase in UVB intensity at Ushuaia, Argentina, and a 285 percent increase at the Palmer Research Stations on Antarctica. These southern climes, of course, lay underneath the ozone hole.

But the bad news is not for penguins and Southern Hemisphere residents alone. Researchers at Oulu University Hospital in Finland reported last year that during recent decades, stratospheric ozone thickness declined between 10 to 40 percent during winter and spring months over portions of the Northern Hemisphere.

This is significantly larger than an estimate in a 1993 report from Germany that indicated widespread global ozone depletion of 3 percent (specifically between 65 degrees North and South latitude). Four years after the German study was published, University of London scientists confirmed its data. Measurements in unpolluted areas such as Antarctica, parts of South America, and pieces of mid to high Northern Hemisphere latitudes definitively pointed to thinning ozone and a corresponding increase in UVB.

This appreciable decrease in ozone and increase in UVB has been so widely documented that a general rule of thumb has emerged: a 1 percent reduction in ozone leads to a 2 percent increase in UV intensity.

The research further indicates that a 2 percent increase in UV intensity leads to a 2 to 4 percent increase in skin cancers. More than 1.3 million Americans are diagnosed each year with the disease. In fact, Nonmelanoma skin cancer is the most common form of cancer today. And nearly 50,000 Americans die annually from the more malignant type of skin cancer, melanoma. Skin cancer researchers have declared the disease to be epidemic in proportion.

The fluctuating ozone hole, often forgotten as an imminent ecological crisis, is a problem that is far from solved. It was first addressed at the Vienna Convention of 1985, where its discovery led to international restrictions on ozone-depleting substances. However, the Montreal Protocol and Copenhagen Amendments, while attempting to address the problem at hand, incorporate measures allowing for an additional 10 percent increase of skin cancer diagnosis by 2060.

In 1990, scientists at the State University of Utrecht in the Netherlands proclaimed that an increase in skin cancer due to an increase in UV is one of the best-quantified effects of stratospheric ozone depletion.

A British Journal of Cancer report, however, contends that the dramatic increases in the incidence rate of malignant melanoma over a 20-year period are not accompanied by increases in exposure to ultraviolet radiation, based on measured ozone levels. These detractors say that a marked increase in exposure to UVB has less to do with the lack of an ozone shield than from the amount of time spent outdoors. This objection raised to the link between ozone depletion and skin cancer points to human behavior rather than environmental factors as a root cause of the health concern.

The Outdoor Industry Association (OIA) estimates that as much as 75 percent of the U.S. population over the age of 16 participates in some form of regular outdoor recreation, creating a $35 billion retail market for outdoor goods and services.

Yet despite these detractions, most research agrees that current and future increases in ultraviolet radiation exposure due to ozone depletion will tend to exacerbate a trend toward higher incidence rates of melanoma.

Increases in the rate of skin cancer diagnosis, though, are not the only human health issue associated with increases in UVB radiation exposure. Increased UVB exposure also promotes cataract formation and leads to "immunological perturbations," according to a report from the M.D. Anderson Cancer Research Center based at the University of Texas.

Just like other species, humans' health is dictated by the health of our environment (Earth). This is a fundamental tenet of biology. Ozone plays a central and key role in regulating the amount of harmful UVB exposure we receive from the sun. Continued depletion of ozone promises continued increases in skin cancer diagnoses and other more ominous health concerns.

Copyright 2001 Environmental News Network


All columns archived here are copyright © 2000 by Michael Jessen, all rights reserved. If you wish to print an individual column for your own use, please do so. If you wish to publish any of the columns in either print or electronic format, please contact the author at toenail@netidea.com to arrange appropriate payment.