As many as 60,000 people a year die from too much sun, mostly from malignant skin cancer, the World Health Organization reported on Wednesday.
It found that 48,000 deaths every year are caused by malignant melanomas, and 12,000 by other kinds of skin cancer. About 90 percent of such cancers are caused by ultraviolet light from the sun.
Radiation from the sun also causes often serious sunburn, skin aging, eye cataracts, pterygium — a fleshy growth on the surface of the eye, cold sores and other ills, according to the report, the first to detail the global effects of sun exposure.
"We all need some sun, but too much sun can be dangerous — and even deadly. Fortunately, diseases from UV such as malignant melanomas, other skin cancers and cataracts are almost entirely preventable through simple protective measures," Dr. Maria Neira, Director for Public Health and the Environment at WHO, said in a statement.
Ultraviolet light is needed to activate production of vitamin D in the body, which prevents rickets, osteomalacia and osteoporosis. It may also affect some some cancers and immune disorders.
The report, available on the Internet, advises that people seek shade, use sunscreen with an SPF of at least 15, and stay out of tanning salons.
"The application of sunscreens should not be used to prolong sun exposure but rather to protect the skin when exposure is unavoidable," the report advises.
Snow, sand and sea foam reflect ultraviolet light, the report notes, and thinning ozone filters out less and less of it.
"Ultraviolet radiation can neither be seen nor felt," the study noted. Time of day, latitude and cloud cover all affect the amount of radiation reaching the ground.
"A person's skin type is also important. Fair skinned people suffer from sunburn much more readily than dark-skinned people," WHO said in a statement.
But it detailed ill effects from too much sun around the globe, especially cataracts in Africa, Latin America, the Middle East and Southeast Asia.