Dear Andrew,

thank you for the prompt reply, and for clarifying my mistake. 

I hypothesized that age will influence control and patient group differently and want to control for age-group interactions.

Will it be the following:

1 1 12 12
1 1 10 10
1 1 8   8
1 0 11 0
1 0 15 0
1 0 18 0

the first column being constant, second column being groups (1- Control, 0-Patient), third column being age, and the fourth to control for age-group interactions?

And to test for group effects, the contrasts to be [0, 1, 0, 0] based on prior hypothesis that control>patient?

Thanks,
Lynette