(7 points) Low-dose aspirin ~ Many Americans take a baby aspirin every day to reduce their risk of having a heart attack, getting cancer and even possibly dementia. But is it really a good idea? Researchers launched a large study in 2010. They enrolled 19,114 older people in the study, with 16,703 in Australia and 2,411 in the United States. The U.S. portion included white participants ages 70 and older, and African-Americans and Hispanic subjects ages 65 and older. None of the participants had heart disease, dementia, or physical disability at the beginning of the study. Participants were randomly assigned to take either 100 milligrams of aspirin every day or a placebo. Researchers kept track of whether the participant died, developed dementia or persistent disability, and/or experienced a major hemorrhage (bleeding), among other health outcomes. People in the study were followed for an average of 4.7 years. There is still strong evidence that a daily baby aspirin can reduce the risk that many people who have already suffered a heart attack or stroke will suffer another attack. But for older, healthy people, the risks outweigh the benefits for taking low-dose aspirin. The primary risk is bleeding. The study confirmed that a daily baby aspirin increases the risk for serious, potentially life-threatening bleeding, while not reducing the risk of death, dementia, or persistent physical disability. Researchers recorded observations for many variables for each volunteer. 1. The summary above describes an ? because OA. People volunteered to participate in the study. O B. Some people take aspirin without consulting their doctors. OC. Researchers assigned participants to take aspirin or a placebo. OD. The study followed people for about 4.7 years