London: Indoor tanning is already an established risk factor for malignant melanoma, the less common but deadliest form of skin cancer.
Now, a new analysis led by UCSF has confirmed that indoor tanning significantly increases the risk of non-melanoma skin cancers, the most common human skin cancers.
In the most extensive examination of published findings on the subject, the researchers estimate that indoor tanning is responsible for more than 170,000 new cases annually of non-melanoma skin cancers in the United States – and many more worldwide.
Young people who patronize tanning salons before age 25 have a significantly higher risk of developing basal cell carcinomas compared to those who never use the popular tanning booths, the researchers reported.
“The numbers are striking – hundreds of thousands of cancers each year are attributed to tanning beds. This creates a huge opportunity for cancer prevention,’’ said Eleni Linos, MD, DrPH, an assistant professor of dermatology at UCSF and senior author of the study. “
The study was a meta-analysis and systematic review of medical articles published since 1985 involving some 80,000 people in six countries and data extending back to 1977.
It adds to the mounting evidence on the harms of indoor tanning, showing significant elevated risk of the most common forms of skin cancer.
“Several earlier studies suggested a link between non-melanoma skin cancer and indoor tanning. Our goal was to synthesize the available data to be able to draw a firm conclusion about this important question,’’ said co-author Mary-Margaret Chren, MD, professor of dermatology at UCSF.
The researchers studied both early life exposure and regular use of tanning booths.
Those who exposed themselves to indoor tanning had a 67 percent higher risk of developing squamous cell carcinoma and a 29 percent higher risk of developing basal cell carcinoma, compared to people who never did indoor tanning.
The scientists noted several limitations including the broad timeframe that the data spans. Also, indoor tanning devices have changed over the years “from high UVB output to predominantly UVA output,’’ the researchers said.
But they pointed out that numerous studies have indicated that both UVB and UVA can cause significant skin damage.
“Australia and Europe have already led the way in banning tanning beds for children and teenagers, and Brazil has completely banned tanning beds for all ages. I hope that our study supports policy and public health campaigns to limit this carcinogen in the United States,’’ Linos said.
The study will be published online in BMJ, the British general medical journal.