Question

Researchers are interested in the relationship between depression and bacterial vaginosis among expecting mothers enrolled in...

Researchers are interested in the relationship between depression and bacterial vaginosis among expecting mothers enrolled in a case-control study. Suppose the following computerized printout reports a summary table for the relationship.

Table of dep by bv

dep

bv

_case

control

Total

_exposed

 35
 89
 124

nonexposed

 45
 503
 548

Total

 80
 592
 672

Calculate the prevalence of the exposure in the investigation.

 cases controls total exposed 35 89 124 nonexposed 45 503 548 Total 80 592 672

Prevalence is the number or proportion of subjects/individuals with some exposure to depression in a point in time or period of time, in our case.

prevalence of the exposure = no of cases when exposed to depression/ total no. of individuals in the study = 35/672 = 0.0521

we could also, find the prevalence ratio = prevalence of the disease with exposure/ prevalence of the disease without exposure.

= (35/672)/(45/672)= 35/45= 0.778

which tells us, that prevalence of the disease with exposure is less than the prevalence of the disease without exposure.