A new study has found no evidence that sunscreen, commonly used to reduce the
risk of skin cancer, actually increases the risk.
     Researchers from the Umversity of Iowa based their findings on a revicw of 18 earlier
studies that looked at the association between sunscreen use and melanoma(黑素瘤 ).
They said that they found flaws in studies that had reported associations between sunscreen
use and higher risk of melanoma.
     Most health experts believe that by protecting the skin from the harmful effects of
the sun, sunscreen helps prevent skin cancer, which is increasing in incidence (发生率)
faster than any other cancer in the United States.
     But questions have been raised about sunscreen and whether it may have the opposite
effect, perhaps by allowing people to remain exposed to the sun longer without burning.
     The researchers said that among the problems with some earlier studies is that they
often failed to take into account that those people most at risk for skin cancer-people
with fair skin and freckles(雀斑) ,for example-are more likely to use sunscreen. As a
result , it may appear that sunscreen users get cancer more often.
     The studies , which generally relied on volunteers to recall their sunscreen use,were
also unable to prove how well the products had been applied , Said the new study.