Table 4.
Regression coefficients obtained from the multivariate negative binomial regression model for modeling the daily number of cigarettes among college students.
| Covariates | β (SE) | p-value | Exp(β) | 95% Confidence Limits | |
|---|---|---|---|---|---|
| Intercept | −0.92 | 0.435 | 0.4 | 0.04 | 4.01 |
| Gender | |||||
| Female | Reference category | ||||
| Male | 2.25 | <0.0001 | 9.45 | 6.25 | 14.28 |
| Birth order | |||||
| First | Reference category | ||||
| Second | 0.3 | 0.208 | 1.35 | 0.84 | 2.18 |
| Third | 0.03 | 0.901 | 1.03 | 0.6 | 1.77 |
| Forth | 0.72 | 0.027 | 2.05 | 1.09 | 3.9 |
| Marital status | |||||
| Single/divorced | Reference category | ||||
| Married | −0.09 | 0.797 | 0.91 | 0.47 | 1.78 |
| City | |||||
| Hometown (Hamadan) | Reference category | ||||
| Surrounding towns | −0.06 | 0.845 | 0.94 | 0.53 | 1.68 |
| Towns of other provinces | −0.51 | 0.072 | 0.60 | 0.35 | 1.05 |
| Residence | |||||
| Dormitory | Reference category | ||||
| Parents’ house | 0.19 | 0.451 | 1.21 | 0.74 | 1.97 |
| Student’s education level | |||||
| BSc | Reference category | ||||
| MSc | −0.06 | 0.881 | 0.94 | 0.45 | 1.98 |
| MD | 0.27 | 0.225 | 1.31 | 0.84 | 2.05 |
| PhD | −0.77 | 0.212 | 0.46 | 0.14 | 1.55 |
| The average grade of the previous semester | −0.01 | 0.935 | 0.99 | 0.88 | 1.12 |
| Interested in the discipline | |||||
| Yes | Reference category | ||||
| No | 0.51 | 0.079 | 1.67 | 0.94 | 2.97 |
| Optimistic about future | |||||
| Yes | Reference category | ||||
| No | −0.19 | 0.529 | 0.83 | 0.45 | 1.5 |
| Having a boyfriend/girlfriend | |||||
| No | Reference category | ||||
| Yes | 0.39 | 0.079 | 1.48 | 0.96 | 2.27 |
| Experiencing a break-up | |||||
| No | Reference category | ||||
| Yes | 0.46 | 0.027 | 1.58 | 1.05 | 2.40 |
| Having sexual intercourse | |||||
| None | Reference category | ||||
| Heterosexual | 0.95 | 0.002 | 2.59 | 1.42 | 4.68 |
| Homosexual | 1.14 | <0.0001 | 3.13 | 1.71 | 5.73 |
| Drug abuse (opium/Psychedelic) | |||||
| No | Reference category | ||||
| Yes | 1.79 | <0.0001 | 5.99 | 3.13 | 11.51 |
| Suicide thought lifetime | |||||
| No | Reference category | ||||
| Yes | 0.03 | 0.919 | 1.03 | 0.53 | 2.03 |
| Suicide attempt lifetime | |||||
| No | Reference category | ||||
| Yes | 0.52 | 0.176 | 1.68 | 0.79 | 3.53 |
| Using social media | |||||
| No | Reference category | ||||
| Yes | −0.28 | 0.424 | 0.76 | 0.38 | 1.5 |
| GHQ28 | |||||
| Not having psychiatric distress | Reference category | ||||
| Having psychiatric distress | 0.001 | 0.994 | 1 | 0.66 | 1.52 |
| C | 5.01 | <0.0001 | — | — | — |