Read Health Studies With Caution

If you're like most people in this era of fast-breaking health stories, you've probably encountered breathless reports about new studies on anything from the dangers of coffee to the benefits of fish oil.

You've probably felt confused and frustrated as you try to evaluate studies that seem to contradict each other. Does margarine cut your risk of a heart attack, or not? Is coffee a health hazard for pregnant women, or not?

How can consumers cut through the tangle to find accurate, useful information?

The sunscreen example

When a researcher at Memorial Sloan-Kettering Cancer Center in New York released a study recently indicating that sunscreens don't prevent skin cancer, the uproar was immediate. According to epidemiologist Marianne Berwick, Ph.D., a study of several hundred Connecticut residents over four decades demonstrated "there is no convincing evidence that sunscreens prevent melanoma... and it is not safe to rely on sunscreens."

Some dermatologists challenged Dr. Berwick's findings. Others conceded she had raised significant questions, but they warned that the jury was still out on sunscreens.

Most experts pointed out that sunscreens do help prevent sunburn. They suggested that we not rely solely on sunscreens, but use them as part of an overall sun protection plan that includes shunning the midday sun, wearing sun-blocking clothes (including hats) and applying sunscreen often.

Dr. Berwick agrees that contradictory reports can baffle consumers. The epidemiologist, who evaluated 10 other sunscreen studies while preparing her report, says her study did not pretend to be the final word.

Bottom line: We don't know

"My conclusion was simply that my data didn't show that sunscreen helps," says Dr. Berwick. "Other researchers have found that it does prevent skin cancer -- and a few of the studies I looked at showed that using sunscreens actually increased the risk of melanoma. The bottom line on my research was that we don't know the answer -- so we shouldn't make assumptions about sunscreens and skin cancer.

"There's no doubt that it's easy to get confused by all of the conflicting studies being published these days," she says.

Don't rely on one study

"Part of the problem is that the news media often report the results of a single, isolated study as if they are the final word on a subject," Dr. Berwick adds. "But that's simply not realistic. Instead, we should be looking at the entire range of studies on a particular health issue, in order to get a comprehensive picture."

The fact that a study was published in a prestigious journal and then picked up by the national media doesn't mean it was well done, experts say.

"People should evaluate the sources of these studies very carefully," says Neal Zimmerman, M.D., a health-information specialist at Union Memorial Hospital in Baltimore. "Obviously, you need to make sure that the study was performed by reputable, medically trained researchers who are operating independently."

What can you do?

Researchers suggest these simple strategies to avoid information overload:

• Don't overreact to a single study. Remember that new health reports often make headlines for a day or two, then vanish. Instead of panicking over the disturbing implications of one study, find out what other researchers have written on the topic.

• Evaluate the source of any new study. The most reliable studies are those published in peer-reviewed journals such as the Journal of the American Medical Association and the New England Journal of Medicine. (The least reliable, researchers say, are those released during medical meetings or at news conferences.)

• Before changing your lifestyle, weigh the actual risks. If a new study suggests that eating ice cream every day just slightly increases your risk of cholesterol-related heart disease over a lifetime, you should evaluate that news in the context of everything you already know about fat from reliable sources.

• Check reputable health information sites on the Internet. You may find that medical information specialists at sites run by credible outfits such as the AMA have already done your homework by gathering, sorting and evaluating studies on a particular topic. Stick with organizations you can trust.

• Recall that one of the best sources of personal health information is your family doctor. In medicine, experts say, there are no "one-size-fits-all" solutions. The best place for answers to specific questions about your medical condition is your doctor's office.