Question

Choose the study design that best fits the following description: The records of 8,047 white male smelter workers, believed to have been exposed to high quantities of arsenic, were gathered for those who began work between 1938 and 1963. Death certificates were examined to ascertain the cause of death for this group up until 2000. They were compared to death certificates from the workers in other occupations of the same race, gender and time period. Higher rates of mortality from respiratory cancer and heart disease were found among those who had worked at least 15 years as smelter workers compared to those in other occupations.

a) Randomized Clinical Trial

b) Retrospective Cohort Study

c) Cross-Sectional Study

d) Prospective Cohort Study

e) Ecologic Study

f) Case Control Study

Answer 1

Answer: (f) Case Control Study

Explanation: Cohort studies are a type of medical research, by recording disease occurrence in a defined group, provides measures of incidence, or mortality rates, and it is these rates that provide the basic measures of disease risk. By allowing one to measure the basic risk associated with different levels and kinds of exposure, cohort studies provide the inspiration of cancer epidemiology. It so happens, however, that a frequently convenient way of expressing the surplus risk in one group compared to a different is in terms of the ratio of the rates in the two groups, and to estimate the ratio of the rates one can use just a sample of the overall cohort. Since it is often easier and cheaper to obtain information on a sample rather than on the entire cohort, the case-control study has become widely adopted in cancer epidemiology as an alternative to the cohort study.

Advantages of his study includes,

When the disease or outcome being studied is rare.

When the disease or outcome features a long induction and latent period (i.e., an extended time between exposure and therefore the eventual causal manifestation of disease).

When exposure data is difficult or expensive to get .

When the study population is dynamic.

When little is understood about the danger factors for the disease, case-control studies provide how of testing associations with multiple potential risk factors.