Table 3. Results of logistic regression analysis of smoking among Japanese medical students.
| Crude OR | 95% CI | P | Adjusted OR | 95% CI | P | |
| Sex | <0.001 | <0.001 | ||||
| Male | 1.00 | reference | 1.00 | reference | ||
| Female | 0.25 | 0.16–0.37 | 0.29 | 0.18–0.48 | ||
| Age (years) | <0.001 | 0.480 | ||||
| 21–24 | 1.00 | reference | 1.00 | reference | ||
| 25–29 | 2.37 | 1.66–3.41 | 1.35 | 0.81–2.24 | ||
| 30– | 1.43 | 0.69–2.98 | 0.86 | 0.30–2.42 | ||
| Type of university | <0.001 | 0.031 | ||||
| National/public | 1.00 | reference | 1.00 | reference | ||
| Private | 2.13 | 1.59–2.85 | 1.83 | 1.06–3.16 | ||
| Smoking restriction | 0.769 | 0.675 | ||||
| Total smoking ban | 1.00 | reference | 1.00 | reference | ||
| Designated smoking area | 0.96 | 0.70–1.30 | 1.12 | 0.65–1.94 | ||
| Cigarette vending machines | 0.004 | 0.169 | ||||
| Yes | 1.00 | reference | 1.00 | reference | ||
| No | 0.41 | 0.22–0.75 | 0.52 | 0.21–1.32 | ||
| Sale of cigarettes in campus store | 0.894 | 0.581 | ||||
| Yes | 1.00 | reference | 1.00 | reference | ||
| No | 0.97 | 0.66–1.44 | 0.83 | 0.43–1.61 | ||
| Parent smoker | 0.036 | 0.414 | ||||
| No | 1.00 | reference | 1.00 | reference | ||
| Yes | 1.38 | 1.02–1.86 | 1.18 | 0.80–1.75 | ||
| Sibling smoker | <0.001 | <0.001 | ||||
| No, or no siblings | 1.00 | reference | 1.00 | reference | ||
| Yes | 2.35 | 1.73–3.18 | 2.08 | 1.40–3.09 | ||
| Drinking alcohol | <0.001 | <0.001 | ||||
| No | 1.00 | reference | 1.00 | reference | ||
| Yes | 2.72 | 2.00–3.69 | 2.38 | 1.62–3.50 | ||
| Drinking coffee | <0.001 | <0.001 | ||||
| No | 1.00 | reference | 1.00 | reference | ||
| Yes | 1.98 | 1.47–2.67 | 2.36 | 1.59–3.50 | ||
| Participate in school club activities | 0.069 | 0.247 | ||||
| No | 1.00 | reference | 1.00 | reference | ||
| Yes | 0.74 | 0.53–1.02 | 0.77 | 0.49–1.20 | ||
| Exercise | 0.895 | 0.168 | ||||
| No | 1.00 | reference | 1.00 | reference | ||
| Yes | 0.98 | 0.73–1.31 | 0.76 | 0.52–1.12 | ||
| Insomnia | <0.001 | <0.001 | ||||
| No | 1.00 | reference | 1.00 | reference | ||
| Yes | 1.96 | 1.42–2.72 | 2.16 | 1.38–3.40 | ||
| Sleep duration (hours) | 0.037 | 0.030 | ||||
| 6> | 1.41 | 1.02–1.95 | 1.59 | 1.05–2.41 | ||
| 6≦ | 1.00 | reference | 1.00 | reference | ||
| ESS (Daytime sleepiness) | 0.504 | 0.382 | ||||
| 11> | 1.00 | reference | 1.00 | reference | ||
| 11≦ | 0.86 | 0.54–1.35 | 0.77 | 0.43–1.38 | ||
| GHQ | 0.755 | 0.725 | ||||
| 4> | 1.00 | reference | 1.00 | reference | ||
| 4≦ | 0.96 | 0.71–1.28 | 0.93 | 0.63–1.39 | ||
Data were collected from December 2006 through March 2007.
For each item, the subjects who did not answer the related questions were excluded from analyses.
ESS: Epworth Sleepiness Scale.
GHQ: General Health Questionnaire.