I have decided to use Poisson regression for my analysis of weight gain and would like to get a second opinion about whether it's appropriate.
Weight is measured at baseline and and a second value is taken a few months later, but the number of months and therefore the observation time varies greatly. So I thought it would be appropriate to use a threshold weight increase to define what counts as an event, calculate person-time for each subject and use Poisson regression to compare groups (grouping variable to be included in the model). Only one observation will be used for each subject (apart from baseline) and the outcome will be 0 or 1 depending on whether the subject exceeded the threshold weight gain.
*First of all, does Poisson regression seem appropriate in this scenario?
*Can Poisson regression handle several covariates and interactions between them?
*A small number of subjects have more several weight measurements (but most of them don't), is that a problem?