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Risks: From sunscreen to strokes
DEC 21 - A new study in the United States has found no evidence that sunscreen, commonly used to reduce the risk of skin cancer, actually increases the risk. Writing in Annals of Internal Medicine, the researchers based their findings on a review of 18 earlier studies that looked at the relation between sunscreen use and melanoma. Some studies had suggested that using sunscreen reduced the risk of cancer, but researchers may need decades to determine whether newer, more powerful formulas do more than just prevent sunburn, the study said.
The researchers, led by Leslie Dennis of the University of Iowa, said 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 in the United States, for example, is increasing in incidence faster than any other kind of cancer.
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. Among the problems with some earlier studies, the report argues, is that the researchers often failed to take into account that those people most at risk for skin cancer - people with fair skin and freckles, 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 establish how well the products had been applied, the new report says. “The effects of prolonged exposure to sun due to use of sunscreens are unclear, and further study is needed,” the authors wrote. The research did not look at new sunscreen products that protect against a broader range of the sun’s rays and are waterproof. Stroke and Alzheimer’sA study finds that having a stroke puts people at higher risk for developing Alzheimer’s disease. Writing in The Archives of Neurology, researchers said the risk was especially high for people with cardiovascular problems or some types of diabetes. The lead author was Lawrence Honig of the Columbia University College of Physicians and Surgeons.
The senior author, Richard Mayeux, a neurologist at Columbia, said that mechanism for the increased risk was unclear. It may be that strokes are directly involved in the onset of Alzheimer’s or it may simply be that it affects its symptoms.
One theory is that the brain injury caused by a stroke speeds the course of Alzheimer’s in people who are already developing the disease but have no symptoms. The study found, for example, that dementia in Alzheimer’s patients set in at an earlier age among people who had had strokes. It is also possible, but unlikely, the researchers said, that the connection works the other way, that having Alzheimer’s predisposes people to strokes.
The findings were based on a study of more than 1,700 Medicare patients from 1992 to 1999. Overall, the researchers found that patients who had had strokes were 60 percent more likely to develop Alzheimer’s than those who had not.
Among other facets, Mayeux said, the findings demonstrate the importance of diagnosing and treating health problems that can lead to strokes early in life. Pollution and heart disease Minuscule particles in air pollution pose a greater risk to the heart than to the lungs, says a study released this week. The particles, called particulate matter, have long been suspected of causing ailments of the heart and lungs. But writing in the journal Circulation, the lead author, C. Arden Pope of Brigham Young University, and his colleagues said new research made it clear that the heart was more affected. The study is in the online version of the journal.
Particulate matter is emitted by vehicles, coal-burning plants and other industrial sources. Because the material enters the body through the lungs, the assumption once was that the lungs bore the brunt of the damage.
The researchers came to their conclusions after correlating pollution data from more than 150 cities over 16 years with health data regarding 500,000 people collected by the American Cancer Society. The danger, they said, was posed by particulate matter less than 2.5 microns (smaller than three-thousandths of a millimeter). Environmental officials assess the level of P.M., as it is known, by measuring how many micrograms there are per cubic meter of air. For each increase of 10 micrograms, the study found, the risk of death from ischemic heart disease went up 18 percent.
Sore throat and antioboticsSore throats are among the most common reasons that children are taken to doctors, and prescriptions for antibiotics are among the most common results.
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