- J M Mcgregor,
- A R Young
- Senior lecturer in dermatology Senior lecturer in photobiology Department of Photobiology, St John's Institute of Dermatology, St Thomas' Hospital, London SE1 7EH
Sunscreens should not be seen as a safe way to prolong sun exposure
Sunlight causes sunburn, photoaging, and skin cancer,1 the price many people seem prepared to pay for a tan. Yet recent studies suggest that tanning is a direct consequence of damage to DNA caused by ultraviolet radiation.2 Even seemingly trivial sun exposure, enough just to turn the skin red, causes considerable damage to both keratinocytes3 and melanocytes and is sufficient for many cells in the skin to sustain lethal doses of ultraviolet radiation. Patients with xeroderma pigmentosum, who are unable to repair this damage, develop skin cancer in the first 5-10 years of life, but in normal individuals the accumulation of genetic alterations sufficient to cause skin cancer may take five to six decades. However, despite the efficiency of our DNA repair machinery, the rising incidence of both melanoma and non-melanoma skin cancer in fair skinned populations suggests that in many cases DNA repair is not able to keep pace with 20th century lifestyle.
In recognition of the economic and public health concerns, the government's strategy document, Health of the Nation, has as one of its major targets the reversal of the …