Table 4 Odds Ratios (OR) and 95% confidence intervals (CI) for a multinomial regression comparison of the four nicotine dependence subclasses with personality traits, maternal and peer smoking, and interaction effects as predictors (N = 796)

Step 1

0.159

Sex

Class 1

Class 2

1.04

(.66-1.63)

Class 2

Class 3

0.70

(.43-1.15)

Class 3

Class 4

1.17

(.71-1.93)

Education

Class 1

Class 2

0.74***

(.65-.83)

Class 2

Class 3

1.01

(.89-1.05)

Class 3

Class 4

1.04

(.90-1.19)

Age of initiation

Class 1

Class 2

1.02

(.94-1.11)

Class 2

Class 3

0.96

(.73-1.26)

Class 3

Class 4

1.04

(.81-1.33)

Smoking frequency

Class 1

Class 2

.99

(.75-1.33)

Class 2

Class 3

.96

(.73-1.26)

Class 3

Class 4

1.04

(.81-1.33)

Smoking quantity

Class 1

Class 2

1.93

(.61-6.10)

Class 2

Class 3

1.49

(.56-4.01)

Class 3

Class 4

1.19

(.51-2.77)

Step 2

0.010

Extraversion

Class 1

Class 2

0.87

(.67-1.13)

Class 2

Class 3

1.07

(.81-1.43)

Class 3

Class 4

1.18

(.87-1.58)

Neuroticism

Class 1

Class 2

1.16

(.90-1.51)

Class 2

Class 3

0.88

(.66-1.17)

Class 3

Class 4

1.13

(.85-1.51)

Step 3

0.035

Smoking mother

Class 1

Class 2

1.95*

(1.17-3.26)

Class 2

Class 3

2.25**

(1.30-3.87)

Class 3

Class 4

1.34

(.79-2.25)

Smoking friends

Class 1

Class 2

1.47**

(1.12-1.94)

Class 2

Class 3

.98

(.74-1.31)

Class 3

Class 4

.94

(.70-1.25)

Step 4a

0.010

Interaction Extraversion × Smoking friends

Class 1

Class 2

1.48**

(1.13-1.96)

Step 4b

0.011

Interaction Extraversion × Smoking mother

Class 3

Class 4

1.79*

(1.08-2.97)