Table 4 Standardized estimates for control variables genotypes and parental smoking exposure on the intercepts and slopes of cue-induced craving and cognitive craving

Step 1

 Sex

.05

.19

.10

.10

 Education

-.05

.10

.03

.06

 Ethnicity

.05

-.08

.07

-.11

 Age of smoking initiation

-.13

-.19

-.08

-.18

 Baseline smoking

.81**

-.31

.72**

-.35

 DRD2 Taq1A

.15

-.11

.22*

-.21

 DRD4 48 bp VNTR

.06

-.06

.09

-.14

 OPRM1 A118G

.08

.01

.09

.02

 Parental smoke exposure

.07

.08

.12

-.01

 Explained variance (R2)

76 %

21 %

65 %

27 %

Step 2

 DRD2**Parental smoke exposure

.55

-.76**

.52

-.96**

 DRD4**Parental smoke exposure

.32

.25

.49

-.08

 OPRM1**Parental smoke exposure

.02

-.30

-.20

-.18