Study and Measures of Association Example Smoking and Alzheimer\'s Disease

Alzheimer's Disease: Summary of Results Q&A

The summary of results on the case study of AD provides that AD is still a disease of those primarily age 85 and older, and an expensive, time-consuming process. It is not a disease that is appropriate for "large, epidemiologic studies" thus screening strategies are most sell-suited so cohort studies are feasible. Diagnostic workups assist in making studies manageable and successful in diagnosing sources of AD and number of actual cases of AD in the public.

Diagnosis of AD brings with it many problems including fear and social stigma; thus it is beneficial to examine risk factors and distinguish between cognitive impairments that are minimal and evidenced in the public at large and actual early warning signs and preclinical AD. False positives are a common diagnostic problem as signs are common with advancing age and may include, "poor vision, hearing loss, arthritis" which all affect performance on examination which include mental status examination and neuropsychological examination, as do environmental factors which may contribute to examination errors. False positives may be eliminated with careful cross-sectional analysis or observational studies that take into consideration the unique characteristics of the population at large.

1.Do you agree or disagree with answer Case Study 1 -- Why?

An observational study to examine the association between AD and smoking is the best choice given the information provided in the summary, as there are too many influencing factors (environmental, advancing age, altered mental status) that can affect the results leading to a diagnosis of AD (Robert, et al., 2003). Case studies can be beneficial studies in certain circumstances; it may be beneficial in an AD study if the sample size was large enough to accommodate the study. A case study however, typically involves a much smaller sampling of the population (Wang, et al., 1999). Thus, it would more likely provide limited and perhaps biased information regarding the AD population. Observational studies take into consideration a much greater sampling and would take into consideration the errors that may occur due to the aging population that comes with AD (Robert, et al., 2003). Observational studies would also allow the researcher to observe the behaviors and daily lifestyle of the population without interfering with the study subjects.

2.Do you agree or disagree with answer Case Study 4 -- Why?

Cross-sectional studies are most like to provide the best information regarding the linkage between tobacco use and Alzheimer's (Wang, et al. 1999). Alzheimer's is a disease that affects a very large population, but is also very unpredictable in nature to some extent (Robert et al., 2003). In a study testing the hypothesis that smoking provides a protective effect on Alzheimer's disease or dementia (cross-section) on a population-based cohort of just under 700 people, studies suggested that smoking provided a negative effect on Alzheimer's disease. Smoking does not provide a protective effect. Most of the studies related to the link between smoking or tobacco use and AD have been cross-sectional (Jones, Reith, Philpot, 1987; Robert et al., 2003).

Why?

Because cross-sectional analysis provides for observation of the population at large, or a representation of the population, which is critical for studying AD patients; a case study analysis would not provide a large enough sample for providing information for a disease as rampant and variable as AD.

3.Do you agree or disagree with answer Case Study 5 -- Why?

The reliability and validity of proxy respondent information is typically valid in youthful populations (Macarthur, Dougherty & Pless (1997). If the controls were intact, it is likely that this information may be helpful in adding to the information provided from cross-sectional studies. It could contribute significantly to information already gathered on AD. It may not compete with data gathered from observational studies, as this has historically been the primary source of information about AD, however a case control study obtained from controls that were cognitively intact could be comparable to an observational study even on a large population of individuals with AD and dementia, who are less reliable given their mental status difficulties. It is for the most part, a system of checks and balances.

4.Do you agree or disagree with answer Case Study 6 -- Why?

The could be studies that were funded by the tobacco industry; it is not unheard of for say, pharmaceutical companies that wished to put to market a drug to push studies that put their pharmaceutical product in a favorable light. In the same manner, the tobacco industry would seek out studies that would attempt to put tobacco in a favorable light. When tobacco was first discovered, if used moderately without the addictive properties considered, undoubtedly there were many studies published regarding the favorable effects of the product.

However, there are likely far more studies published regarding the negative consequences and effects of tobacco. Studies highlighting the favorable effects of tobacco may also highlight those individuals that are in the earliest stages of AD, rather than those who have already deteriorated rapidly or are in advanced stages of the disease; this would explain why smoking might appear to help the disease, or not have a negative impact or even a positive impact on AD. Many people that are addicted to nicotine feel that it has positive effects on their life. This could be played up or on in marketing campaigns.