Question

Discussion #1:

1. Classify each of the following studies as experimental, observational/cohort, observational/case- control, or not an epidemiologic study and provide a rationale for your response.

A. Vietnam Experience Study: Subjects were several thousand soldiers stationed in Vietnam from 1969-1971 and several thousand soldiers stationed in Europe from 1969-1971. In the mid-1980’s, investigators determined and compared the death rate and prevalence of illness in both groups.

B. End-stage Liver Cancer Study: Subjects were 59 patients with end-stage liver cancer. All were given a new treatment. The monthly survival was charted over 2 years.

C. Trichinosis Study: Subjects were persons with laboratory-confirmed trichinosis, and one “healthy” friend of each. All subjects were asked about their consumption of pork and other meat products.

D. Immunization Study: Subjects were children enrolled in a health maintenance organization. At 18 months, each child was randomly given one of two types of vaccine against Haemophilus influenzae. Parents were asked to record any side effects on a card and mail it back after 2 weeks.

Answer 1

A. Vietnam Experience Study: Subjects were several thousand soldiers stationed in Vietnam from 1969-1971 and several thousand soldiers stationed in Europe from 1969-1971. In the mid-1980s, investigators determined and compared the death rate and prevalence of illness in both groups.

It is a retrospective cohort study because the investigators determined and compared the death rate and prevalence of illness in both groups according to data available in both groups.

B. End-stage Liver Cancer Study: Subjects were 59 patients with end-stage liver cancer. All were given a new treatment. The monthly survival was charted for over 2 years.

It is an experimental study but there is no comparison group so, you can not compare the data.

C. Trichinosis Study: Subjects were persons with laboratory-confirmed trichinosis and one “healthy” friend of each. All subjects were asked about their consumption of pork and other meat products.

it is an observational/case-control study because the investigators following backward from effects to cause.

D. Immunization Study: Subjects were children enrolled in a health maintenance organization. At 18 months, each child was randomly given one of two types of vaccine against Haemophilus influenzae. Parents were asked to record any side effects on a card and mail it back after 2 weeks.

it is an experimental study because there are 2 groups of children who are experimented with 2 new types of vaccines.