How to calculate relative risk in R language

Question

How to calculate relative risk in R?

This is the input:

names(DS)
Tab<-table(DS[,5],DS[,11],DS[,3])

      No Yes
  No   4  16
  Yes  40 168

I'm new to R language, any help would be appreciated.

Answer 1

The risk can be calculated by using this formula (pos1/total1)/(pos2/total2) where pos1 denotes the number of cases in the first group, pos2 in the second group, and the total variables are the group totals

However, the epitab function of the epitools package, is needed for your problem:

## maybe:
##   install.packages("epitools")
library("epitools")

For input formats, try this:

tab <- matrix(c(4,16,40,168),byrow=TRUE,nrow=2)
epitab(tab,method="riskratio")
## $tab
##           Outcome
## Predictor  Disease1        p0 Disease2        p1 riskratio     lower    upper
##   Exposed1        4 0.2000000       16 0.8000000  1.000000        NA       NA
##   Exposed2       40 0.1923077      168 0.8076923  1.009615 0.8030206 1.269361
##           Outcome
## Predictor  p.value
##   Exposed1      NA
##   Exposed2       1