I am trying to doing analysis of interaction effects of 1-7 dichotomous or polychotomous dependent variables (nutrition type, either 2 or 3 levels) and one dichotomous variable (young or old age) on dichotomous dependent variable (hyptertension, yes or no).

My thought is that as you get older, your nutrition changes as a partial explanation of the increased prevalence of hypertension seen in aging.

One thought I had was to to assess the interaction of the 3 variables using a chi-square value calculated by the log-linear method.

I would use 1 of the 7 physical activity variables at a time in a 2 x 4 contingency table with hypertension and age as defined below

Rows (nutrition variable) (A)

Columns (Hypertension) (B)

Strata (age) (C)

The interaction would be the ABC combination.

Should I only test one nutrition variable at a time with hypertension and age or should I consider them all at once in a 9 way interaction.

One issue I have is I do not understand the difference between a 2x2x2 and 2x4 contingency table.

Should I bother with the log-linear method or can I answer everything I want with logistic regression.

I know i can use logistic regression to get individual effects of each independent variable on probability of having hypertension but I'm confused about how to test the interaction effects. Is it as simple as testing for differences among the beta coefficients?

Any thoughts, I have just become more confused trying to read up on these issues.

Thank you!