In 1993 a case control study was conducted to assess a possible association between serving in the Persian Gulf War in 1

[answerhappygod]

In 1993 a case control study was conducted to assess a possible
association between serving in the Persian Gulf War in 1991 and the
subsequent diagnosis of neurological diseases. Researchers compared
the military records of 750 Army soldiers seen for neurological
symptoms to 1500 Army soldiers seen for non-neurological symptoms.
In late 1991 and 1992 Army officials were concerned about the
health of soldiers who served in the Persian Gulf War. They were
therefore more likely to refer soldiers with neurologic symptoms
who had served in the Persian Gulf War vs. Army soldiers with
similar symptoms who had not served in the Persian Gulf War. The
study concluded that Army soldiers who served in the Persian Gulf
War had 50% more risk of having subsequent neurological disease vs.
those who did not serve in the Gulf War.
a- Do you think this conclusion is correct? Discuss your
analysis and rationale. Subsequent analyses showed that the
investigators often failed to identify subjects with mild
neurological diseases among those who did not serve in the Gulf
War.
b- What was the likely effect of this failure on relative risk?
Discuss your train of thoughts and rationale.