Manila, May 10, 2003 by Tyrone M. Reyes, M.D., The Philippine STAR - Hot dogs cause cancer? Researchers say yes.

New warnings revive fears about the danger of eating hot dogs particularly among children.

Study links hot dog to cancer.

Ingestion by children boosts leukemia risk, report says,

So went the headlines in the Los Angeles Times, the New York Times, and the Washington Post, back in June of 1994. These came on the heels of three studies published simultaneously in a cancer research journal.

One of the studies found that children who eat more than 12 hot dogs a month have nine times the normal risk of developing childhood leukemia. The second suggested that children born to mothers who eat at least one frank a week during pregnancy have double the normal risk of developing brain tumors. The third traced brain tumors in children to fathers who ate hot dogs before conception. The risk of leukemia to children born to fathers who consumed hot dogs regularly was 11 times normal.

The problem: The three studies – and most certainly the media commentary they attracted – were riddled with scientific holes. In fact, with breakthroughs announced almost every day, it’s hard to separate reality from wishful thinking. Therein lies the difficulty at the heart of the matter. If scientists and the media can’t always look at research with a cool eye, how in the world are you supposed to?


So, how can you judge the validity of the health news coming to you? Here are five questions to ask yourself as you read study results or hear them in the news. These should help you put health reports into perspective as you try to make informed decisions about how to improve or maintain your lifestyle habits.

• Who said it and where? The articles in many medical journals – including the New England Journal of Medicine, the Journal of the American Medical Association, and the Annals of Internal Medicine – are reviewed by fellow scientists in a process called peer review. They must pass strict guidelines for scientific accuracy and are therefore a pretty reliable source of information. Research results that are announced before they appear in a peer-reviewed journal may be premature and unreliable.

• How was the study designed? Did the study include a control (comparison) group? Were people studied or was it lab mice or cells in a tube? If people were studied, how many and for how long? In general, the more people in a study, the less possibility for error in the results.

Was the study designed as a prospective, randomized trial or an observational study? In a prospective, randomized trial, the study is planned in advance, patients are recruited, and then some patients are randomly chosen (to avoid bias) to receive a treatment while others get a placebo (or another treatment being studied). In an observational study, participants are asked a series of questions and then the researchers make correlations. For example, a group of people may be asked about their use of vitamin supplements. The information is then correlated with rates of certain diseases. In general, prospective randomized trials are considered more accurate.

• Have there been clinical trials? A clinical trial is a test of the safety and efficacy of a therapy (usually a drug) using human subjects. In general, these trials include a control group of people who receive a placebo. The trials may also test a proven therapy against a new therapy. In double-blind clinical trials, neither the researchers nor the subjects know which treatments the subjects are receiving, thus eliminating bias. Clinical trials conducted at reputable medical institutions are considered the "gold standard" for scientific studies.

• How big is the risk? Media stories may oversimplify statistics about how likely you are to get a disease. And the statistics may be misleading as to how much you may benefit from a treatment.

For example, a woman has a one-in-eight chance of developing breast cancer at some point in her life. This is true, but risk increases with age. An 81-year-old woman is at greater risk than a 21-year-old woman. In addition, scientists often talk about the relative risk of something happening. But relative risk is a tricky term because it generally refers to a subgroup of people rather than the population as a whole. For example, studies have shown that the drug tamoxifen can reduce the relative risk of breast cancer by up to 50 percent. This does not mean that half of all women who take tamoxifen will be protected. Who will be protected? Actually, only half of the one in eight women statistically at risk for breast cancer.

• How does this news apply directly to me? Currently, not many people over age 65 are included in clinical studies. Some may be considered too frail to handle the rigors of a particular treatment, while others may have other medical conditions that could affect study results. With today’s older adults living longer, healthier lives, more older adults will be recruited for studies, but for now, this age group is underrepresented. When reading about studies, look for the age group of the people studied.


It’s also important to know who did the research. Was the study sponsored by a corporation with a commercial interest, such as a drug or vitamin company – or by a diet doctor hoping to sell a book? Or was it sponsored by a government health agency or university medical center?

A study published in the New England Journal of Medicine, entitled "Coverage by the News Media of the Benefits and Risks of Medications," looked at newspaper and television reports of pravastatin (a cholesterol-lowering drug), alendronate (a drug for osteoporosis), and aspirin as it is used to treat heart disease. Half the articles that cited an expert or scientific study used a source with a financial tie to a drug manufacturer. The highest-quality information is not linked to commercial sources.

Another thing to remember when interpreting health news is that if it sounds too good to be true, it probably is. True, instant medical breakthroughs are few and far between. Remember, too, that in science, things happen incrementally rather than suddenly. When a study is published, it usually suggests rather than proves that something may work. Also, medical practice rarely changes on the strength of just one study. For a study’s results to be considered valid, they must be duplicated by other scientists. Even if the studies are done in humans, be aware that it doesn’t necessarily mean that the findings will apply to everybody. They may be relevant for only specific categories of people, such as those with mild disease, those with severe disease, only men, or only people of a certain age.

On a more positive note, news coverage of conditions that people have traditionally been reluctant to talk about – such as incontinence and impotence – have encouraged many people to come forward and seek medical advice.


How do you handle the fact that health news keeps changing? It may help to remember that when the advice changes in the wake of new findings from well-designed studies, scientists may be closer to finding a solution – or even that long-sought-after cure. For example, as recently as 13 years ago, doctors believed that ulcers were primarily caused by stress and spicy foods. Often, the ulcers became a chronic condition, with patients making many dietary modifications.

But now, thanks to years of research, doctors know that many ulcers are caused by bacteria called Helicobacter pylori (H. pylori), which live on the lining of the stomach and small intestine. Ulcers caused by H. pylori are treated with antibiotics to kill the bacteria, plus an acid reducer, with about 90 percent cure rate. It was, indeed, a breakthrough – but it didn’t happen overnight.

The bottom line: Continue your enthusiastic perusal of the health media – but do it with a critical eye.

Reported by: Sol Jose Vanzi

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