We examined the effects of three time-varying covariates, namely (a) setting (i.e., location such as home, bar, restaurant, etc.), (b) whether or not others were drinking; and (c) time since last cigarette (among smokers only). Setting predicted self-reported vigor (GEE parameter estimate = 0.10, SE = 0.05, z score = 2.11, p = < .05) such that participants reporter higher vigor when drinking in social settings. The addition of ‘setting’ as a time-varying covariate did not significantly alter the results reported in Table 3 and there were no significant Gene × Environment interactions. Others’ drinking was not associated with any of the dependent variables of interest. Time since last cigarette reduced the number of drinking episodes in the models to 135 given that 35.7% of the study sample (n = 40) were smokers. There was no significant effect of time since last cigarette on any of the dependent variables of interest (ps = ns). GEE analyses in which smoking status (regular smoker: yes/no) was used to predict the dependent variables found no significant effects of smoking status (ps = ns) and did not significantly alter the results reported above.
