Bioinformatics: How do a contrast Limma with 3 groups (case/control, age and gender)

Question

I'm a student and I have doubts about how use Limma to contrast the differential gene expression evaluating my three variables: disease (case/control), gender(male/female) and age.

My data is like this: (three columns with the gender, age and the disease)

head(pData(gse))

Data Here:

I know build my experiment over my variable disease:

    design= model.matrix(~ pData(gse)[,"disease"])
    colnames(design)= c("control", "case")

    fit= lmFit(gse, fesign)
    fit1= eBayes(fit)

    topTable(fit1, coef=2, adjust="BH", number= as.numeric(dim(gse)[1]))

But, How I can do a contrast Limma with my 3 variables? Thank for your help!

age= pData(gse)[,"age"]
gender= pData(gse)[,"gender"]
disease= pData(gse)[,"disease"]

age.group= ifelse(age>40,"over40", "under40")

design = model.matrix(~0 + disease + gender + gender:age)

contr.matrix <- makeContrasts(  **???**