I want to run some epigenome wide association studies based on city and pollutant type, could you please suggest if I can get DNA methylation sites (CpG) association based on pollutant type for each city. like below I am trying to find Pb toxic elements association site in four different cities which has varying level of Pb.
#model matrix
var<-model.matrix(~log2Pb*City + sex + Age +CD8T +CD4T +NK + Bcell +Mono, data=targets2)
fit<-lmFit(mval,var)
fit2<-eBayes(fit,trend=TRUE, robust=TRUE)
probe<-topTable(fit2,adjust="BH",coef=2,num=Inf)
try to run interaction model using limma but not sure if this is the right approach