06-25-2017 09:54 PM
I am posting my question again with some additional information.
I wish to study trends in age over time in a study including incident cases of a specific disease. Data were collected during 4 short periods 2 years apart. Each period included different participants (>1000 each). As part of the descriptive analysis I would like to look at trends over time in age of the diagnosed individuals and show p for linear trend.
Would the following be correct for the evaluation of linear trend in age of diagnosed individuals? Any other suggestion?
class (time period);
model AGE=(time period);
contrast 'linear' (time period) -3 -1 1 3;