a. A New York Times health article (August 13, 2009) about a new study reported in the Journal of American Medical Association stated that, “patients with colorectal cancer who were regular aspirin users had a much better chance of surviving than nonusers, and were almost one third less likely to die of the disease, while those who began using aspirin for the first time after the diagnosis cut their risk of dying by almost half.” Which descriptive measure does “one-third” refer to? Interpret.
b. An AP story (September 10, 2003) stated, “Brisk walking for just an hour or two weekly can help older women reduce their risk of breast cancer by 18 percent,” according to an analysis of 74,171 women in the Women’s Health Initiative study. Explain how to form a sample relative risk measure that equals 0.82, for comparing those who briskly walk for an hour or two weekly to those who do not take such walks. In this part and the next one, it may help you to use the result that Percent reduction in risk = (1 - relative risk) * 100%.
c. A Science Daily article (Nov. 17, 2006) reported that taking low-dose aspirin daily reduces the risk of heart attack and stroke, as well as the risk of dying, among patients who previously have had a heart attack or stroke, according to analysis by Duke University Medical Center cardiologists. The researchers found that patients who took low-dose aspirin had a 26% reduction in the risk of a nonfatal heart attack and a 25% reduction in the risk of stroke compared with similar heart patients who did not take aspirin. State this result by defining and interpreting a relative risk for comparing those taking an aspirin a day to those who do not take an aspirin a day for the risk of nonfatal heart attacks.
d. An AP story (February 9, 2011) reported on a preliminary study presented at the International Stroke Conference in California stating that “daily diet soda drinkers (there were 116 in the study) had a 48 percent higher risk of stroke or heart attack than people who drank no soda of any kind (901 people, or 35% of total participants). That’s after taking into account rates of smoking, diabetes, waistline size, and other differences among the groups. No significant differences in risk were seen among people who drank a mix of diet and regular soda.” Report the relative risk value for stroke or heart attack in this statement, and interpret.