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Understanding Scientific StudiesIf you are reading this, you already know that anyone looking for health and medical information is confronted by abundance. Every day the news and websites like this one provide a constant stream of information about medical conditions, treatments and the steps people can take to improve their health. Often, the information is contradictory — over a period of months, we might hear about one study that shows that drinking wine is good for your heart; another that shows that drinking wine makes women more likely to get breast cancer; and still a third that shows that sulfites in wine can cause a potentially fatal allergic reaction.
So, how do you sift through the information and figure out which of these studies is right? Most likely, they all are, at least in some specific way. If they appear to have different results, the probable reason is that they are different kinds of studies that were designed to answer different questions. The mere fact that each is "scientific" tells us very little about what they mean for us as individuals.
Understanding the types of studies reported in health and medical articles can help you begin to evaluate their claims and make informed decisions.
In this first installment of TheDoctor's series on becoming an informed consumer of health information, we will talk about the three major types of research that are often referred to in news articles on medical discoveries — clinical trials, epidemiologic studies and population-based intervention trials. The second installment will discuss how you can figure out whether a health claim you read is credible or not. It discusses the terminology of scientific research and covers the strengths and weaknesses of the various types of medical studies as well as the kinds of conclusions that can honestly be drawn from them. The goal of this two-part series is to make you an informed consumer of health information.
Clinical TrialsResearchers will set up a clinical trial in order to test the effectiveness of a drug or other treatment for a particular disease or disorder. Essentially, a clinical trial is an experiment conducted within a hospital, lab or other controlled environment. For example, researchers might give a carefully screened group of subjects a new allergy medicine and then observe or test their reactions. Subjects need to be carefully screened so that unaccounted-for differences in people do not influence the results. For example, if the study subject group includes people from widely varying age groups or health statuses, some unknown variable from their background — say, forgetfulness about taking pills or an unknown interaction with an over-the-counter medication or ethnic food — might be mistaken for an effect of the drug. Clinical trials are good at establishing cause-and-effect relationships — for instance, proving that diets low in folic acid can cause certain birth defects.
The down side of a clinical study is that its artificiality might mask an effect that would arise in people's real lives. For example, many years ago, an antidepressant drug passed several clinical trials with flying colors, only to have it discovered that it seriously interfered with specific kinds of intellectual performance. The scientists running the clinical trials had tested the drug for all kinds of common side effects — headache, nausea, dehydration and others — but had never thought of testing its effect on activities such as playing chess or solving mathematical problems. Because what they test is usually focused on a specific intervention for a specific problem, clinical trials may need to be repeated using different kinds of subjects before their results can be applied to the general public.
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