Sun beds, not sunshine, cause cancer

Posted on Thu, 30 Jul 09

The World Health Organisation has raised the classification of tanning beds from a possible human carcinogen to a category 1 rating of carcinogenic to humans. In July 2009 a working group of 20 scientists from nine different countries met at the International Agency for Research on Cancer [1]. In their report, published in Lancet Oncology, they reassessed types of radiation carcinogenic to humans and based on current evidence moved tanning beds into the highest risk category for causing cancer in humans [1].

The group reported that “the use of UV-emitting tanning devices is widespread in many developed countries, especially among young women. A comprehensive meta-analysis concluded that the risk of cutaneous melanoma is increased by 75% when use of tanning devices starts before 30 years of age. Additionally, several case–control studies provide consistent evidence of a positive association between the use of UV-emitting tanning devices and ocular melanoma.”

Sun exposure on the other hand may prevent cancer. There is considerable evidence now to suggest that vitamin D, which is synthesised in skin in response to sun exposure, protects against several common cancers. Contrary to popular belief, sun exposure may actually protect against skin cancer or melanoma. In a recent review [2] Michael Holick, a leading vitamin D researcher, pointed out that:

• Most melanomas occur on the skin receiving the least sun exposure

• Several studies have reported that lifetime sun exposure, especially occupational sun exposure, is associated with a reduced risk of developing malignant melanoma

• Children and young adults receiving the greatest exposure to sunlight have a lower risk of dying of malignant melanoma if it should develop.

Current recommendations for sensible sun exposure are 5-15 minutes between 10 am and 3 pm during summer and autumn to maximise vitamin D production then using appropriate sun protection.

References

1. El Ghissassi, F et al. A review of human carcinogens—Part D: radiation. www.thelancet.com/oncology.  Vol 10 August 2009

2. Holick MF. Vitamin D: a D-Lightful health perspective. Nutr Rev. 2008 Oct;66(10 Suppl 2):S182-94.