Studies you may have missed

New studies in non-dermatology journals provide helpful insight into the genetic toll of sun damage, the potential skin-protecting effects of vitamin B3, the sun-exposure threat posed by automobile side windows and the possible (if seemingly improbable) dangers lurking in some produce.

That’s the word from Andrea Murina, M.D., an assistant professor of dermatology at Tulane University School of Medicine. She spoke with Dermatology Times prior to her presentation titled “What You Didn’t Hear at Your Last Journal Club” at the summer meeting of the American Academy of Dermatology in Boston.

On the genetic front, she pointed to a recent Science study [2015 May 22;348(6237):880-6] that examined 234 biopsies of normal eyelid skin in four subjects aged 55-73. The study revealed signs of “driver” mutations that are linked to skin cancer even in seemingly healthy skin.

The study suggests that dermatologists have been wise to treat the areas around pre-cancerous lesions in addition to the lesions themselves, she says.

“Even normal skin with no sign of pre-cancer is so damaged that it’s starting to go on the pathway of cancer,” she says. “We’ve always felt there’s more than meets the eye. Now, the stuff we were thinking the whole time is being validated by research.”

It’s “incredible” to see the amount of damage, she adds, and “it makes you wonder why we don’t see more skin cancer, although we are seeing more than ever.” The findings, she says, also show the importance of urging younger people to protect their skin from the sun.

Dr. Murina is also intrigued by a New England Journal of Medicine study [2016 Feb 25;374(8):790] that suggests twice-daily 500-mg doses of nicotinamide - a form of vitamin B3 - may provide protection against skin cancer. The study linked the supplement to lower levels of non-melanoma skin cancers and actinic keratosis.

“We’ve done other studies on vitamins and skin cancers, and overall they’ve come up pretty short when they’ve been analyzed in long-term clinical trials,” she says. But this study, she says, stands apart.

“We may be able to tell our high-risk patients to take a vitamin,” she says. “But we don’t know why this happens or how long it lasts.” As she notes, the study only look tracked patients for a year.

Dr. Murina also notes a new study in JAMA Ophthalmology [2016 Jul 1;134(7):772-5] that examined UVA exposure in 29 cars from 15 manufacturers. On average, front windshields blocked 96 percent of UVA, while side windows only blocked 71%.

The level of protection varied by car, she says, based on how the window is made. The amount of side-window sun exposure could really add up in certain people, she says, such as those who travel over exceptionally long commutes.

Finally, Dr. Murina points to the oddest research in the bunch: Research suggesting that citrus fruits could spell trouble for the skin.

A Carcinogenesis study [2015 Oct;36(10):1162-8] links higher consumption of citrus products to slightly higher rates of basal cell carcinoma and squamous cell carcinoma over 24-26 years; the research linked consumption of non-citrus whole fruits and juices to a lower risk.

Meanwhile, a Journal of Clinical Oncology study [2015 Aug 10;33(23):2500-8] links higher citrus fruit consumption - especially grapefruit - to higher levels of melanoma over 24-26 years.

What’s happening? It’s possible, Dr. Murina says, that chemicals known as furocoumarins are making skin more sun-sensitive. But for now, she says, there’s not enough evidence to prove causality, so you and your patients may still be able to chow down on citrus in peace.

Disclosure: Dr. Murina reports serving on speakers bureaus (with honoraria) of Celgene and Abbvie and on advisory boards (with honoraria) of Jansen and Suneva. She has also been an investigator (grants) with Genentech.