The sun provides us with life itself, and with many of its pleasures. Yet the sun is enemy as well as friend. More than 90% of all skin cancers are the result of exposure to the ultraviolet radiation of the sun. Does this mean you should never go out in the sun? No one gives this advice. What we do advise is that every person follow the common-sense practices of sun protection - minimizing exposure when the sun is at its peak, wearing protective clothing, including a wide-brimmed hat and sunglasses, using a sunscreen with an SPF of 15 or greater. These tips are particularly important for children, as 80% of a lifetime's sun exposure is experienced before the age of 18.

High-SPF Clothing is Here

Clothes may make the man, but if you're not careful, they may also make you tan. New research from the Morehouse School of Medicine in Atlanta, GA, suggests that the most popular summer garb - shirts and polo shirts - may not adequately protect against solar ultraviolet radiation (UV) and skin cancer.

Fortunately, new "highly UV-protective" clothing is available. And even standard attire provides good sun protection if you know what to look for.

The Well-Dressed Mouse

In the Morehouse study, typical summer shirt fabrics, with a sun protection factor (SPF) of 6.5, were compared against new "special" fabric with a broad-spectrum SPF over 30. The researchers separated hairless mice into four groups of 10: one not exposed to UV; one exposed to UV but unprotected by fabric; one shielded by typical fabric, and one by high-SPF fabric.

For 12 weeks, all groups but the first were exposed to modest but increasingly higher doses of solar-simulating UV on their backs 5 times a week. When the irradiation ended, nine mice in the unprotected group and six in the typical clothing group had premalignant lesions. After 12 more weeks, all mice in these two groups had squamous cell carcinomas (SCC). In contrast, the mice protected by high-SPF fabric showed no reddening, or erythema, throughout the study, and developed no cancers or precancers.

Although the radiation doses required to produce SCC are lower in hairless mice than in humans, the relative degree of protection provided by the typical and special fabrics is the same for both rodents and people. "Thus, the fact that precancerous and cancerous lesions were initiated through the typical fabric is reason for concern," says head researcher J. M. Menter, Ph.D. "Sun-sensitive people who spend a good deal of time outside may be at significant risk for skin cancer even while wearing such fabric. Appropriate sun apparel, however, should offer effective protection against both short-term and long-term photodamage."

High-Tech Protection

The new high-SPF clothing, developed for patients with photosensitive skin or skin cancer, is an obvious choice for appropriate sun wear. Containing colorless compounds, fluorescent brighteners, or specially treated resins that absorb UV, the clothing often provides an SPF of 30 or higher. Some emerging materials, such as resin-coated Japanese formulations, may vastly increase this protection. A team at the University of New South Wales in Australia has developed an astonishing compound that imbues pure close-knit cotton with an SPF of 100.

Tried and True

Even if you don't want to hunt for the special fabrics, a growing body of research shows that a variety of everyday apparel offers excellent sun protection. Some textile fibers, such as polyester crepe, bleached cotton, and viscose, are quite transparent to UV and should be avoided in the sun. But other standard fibers have high SPFs. Unbleached cotton, for example, contains lignins, pigments that act as powerful UV absorbers, while high-luster polyesters and even thin, satiny silk can be highly protective because they reflect radiation.

Weave may be even more important than fabric type. In general, the tighter the weave or knit, the higher the SPF. To assess protection simply, hold the material up to a window or lamp and see how much light gets through. Darker clothes also generally have a higher SPF.

Remember, virtually all garments lose about a third of their sun-protective ability when wet. Also, no clothing can protect you head to toe; be sure to wear sunglasses, and use an SPF 15+ sunscreen on all exposed skin.

For more information about Skin Cancer go to www.skincancer.org, the Skin Cancer Foundation.
The Foundation provides basic information on the prevention, detection, and treatment of skin cancer. We cannot answer specific medical questions. This is best addressed by a medical professional. If you are looking for a doctor or in your area, please click on Physician Finder.