CCInter {EpiStats}

Stratified analysis for case control studies

Description

CCInter is useful to determine the effects of a third variable on the association between an exposure and an outcome. CCInter produces 2 by 2 tables with stratum specific odds ratios, attributable risk among exposed and population attributable risk.

Note that the outcome and exposure variable need to be numeric and binary and coded as "0" and 1". The third variable needs to be numeric, but may have more categories, such as "0", "1" and "2".

Usage

CCInter(x, cases, exposure, by, table = FALSE, full = FALSE)

Arguments

x

data.frame

cases

string: case binary variable (0 / 1)

exposure

string: exposure binary variable (0 / 1)

by

string: stratifying variable (a factor)

table

boolean - TRUE if you need to display interaction table

full

boolean - TRUE if you need to display useful values for formatting

Details

CCInter is useful to determine the effects of a third variable on the association between an exposure and an outcome. CCInter produces 2 by 2 tables with stratum specific odds ratios, attributable risk among exposed and population attributable risk. Note that the outcome and exposure variable need to be numeric and binary and coded as "0" and 1". The third variable needs to be numeric, but may have more categories, such as "0", "1" and "2". CCInter displays a summary with the crude OR, the Mantel Haenszel adjusted OR and the result of a Woolf test for homogeneity of stratum-specific OR.

The option "full = TRUE" provides you with useful formatting information, which can be handy if you're using "markdown".

Value

list:

df1

data.frame - cross-table

df2

data.frame - statistics

df1.digits

integer vector - digit number displayed for kable/xtable

df1.align

character - alignment for kable/xtable

df2.digits

integer vector - digit number displayed for kable/xtable

df2.align

character - alignment for kable/xtable

Note

- You can use lowercas command "ccinter" instead of "CCInter" - The "by" variable (the stratifying variable) can have more than 2 levels

Author(s)

[e-mail]

References

ccinter for Stata by *Gilles Desve*

See Also

CC, CCTable

Examples

library(EpiStats)

data(Tiramisu)
DF <- Tiramisu

# Here you can see the association between wmousse and ill for each stratum of tira:
CCInter(DF, "ill", "wmousse", by = "tira")

# By storing the results in the object "res", you can use individual elements of the results.
# For example if you would like to view just the Mantel-Haenszel odds ratio for beer adjusted
# for tportion, you can view it by typing:

res <- CCInter(DF, "ill", "beer", "tportion", full = TRUE)
res$df2$Stats[3]