Read this article and answer the questions listed below the article
Is Your Lifestyle Healthy?
Consider the following findings from statistical studies:
• • Smoking increases the risk of heart disease.
• • Eating margarine can increase the risk of heart disease.
• • One glass of wine per day can protect against heart disease but increases the risk of breast cancer.
• • Potato chips and sugary sodas are the foods most strongly associated with weight gain.
You are probably familiar with some of these findings, and perhaps you’ve even altered your lifestyle as a result of them. But where do they come from? Remarkably, these and hundreds of other important findings on public health come from huge prospective studies that have provided data for hundreds of smaller statistical studies. The longest-running of these is the Harvard Nurses’ Health Study, which began in 1976 when Dr. Frank E. Speizer decided to study the long-term effects of oral contraceptives. He mailed questionnaires to approximately 370,000 registered nurses and received more than 120,000 responses. He chose to survey nurses because he believed that their medical training would make their responses more reliable than those of the general public.
As Dr. Speizer and his colleagues sifted through the data in the returned questionnaires, they realized that the study could be expanded to include more than just the effects of contraceptives. Today, this research team continues to follow many of the original 120,000 respondents.
Annual questionnaires are still a vital part of the study, allowing researchers to gather data about what the nurses eat; what medicines and vitamins they take; whether and how much they exercise, drink, and smoke; and what illnesses they have contracted. Some of the nurses also provide blood samples, which are used to measure such things as cholesterol level, hormone levels, genetic variations, and residues from pesticides and environmental pollutants. Dr. Speizer’s faith in nurses has proven justified, as they reliably complete surveys and almost always provide properly drawn and labeled blood samples upon request.
After more than three decades of correspondence, both the researchers and the nurses say they feel a sense of closeness. Many of the nurses look forward to hearing from the researchers and say that the study has helped them to pay more attention to how they live their lives. Today, as the original nurses become elderly, the study is beginning to turn out results that should shed light on factors that influence longevity and health in old age.
The success of the Harvard Nurses Study has spurred its expansion and many similar studies of large groups. When you see statistical reports based on these studies, remember the hundreds of thousands of people whose willingness to participate in these studies is making life better for everyone.
Answer the following questions
1. Consider some of the results that are likely to come from the Harvard Nurses’ Health Study over the next 10 to 20 years. What types of results do you think will be most important? Do you think the findings will alter the way you live your life?
2. Explain why the Harvard Nurses’ Health Study is an observational study and not an experiment. Why do you think this is and discuss whether it would be possible to gather similar data by carrying out experiments in a practical and ethical way?
3. The Harvard Nurses’ Health Study is subject to participation bias because only 120,000 of the original 370,000 questionnaires were returned. Should the researchers be concerned about this bias? Do you think that dishonesty can affect this type of observational study? Why or why not?
4. What is the population of interest for this study? What is the sample? Does the population include males? Do you think that the results can be used to make direct inferences about men? Why or why not?