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Table 3 Multivariable models examining the association of substance use perception, presence of close friends with alcohol or drug problems, and family history of alcohol or drug problems with substance use

From: Perception of tobacco, cannabis, and alcohol use of others is associated with one’s own use

Model 1: tobacco use*

Cigarettes/week, IRR (95% CI)

Perception of tobacco use of others (same age/sex), reference group = accurate estimation of tobacco use of others

 

Overestimation of tobacco use by others

1.17 (1.05; 1.32)

Underestimation of tobacco use by others

0.99 (0.84; 1.17)

Close friends with alcohol or drug problems

2.08 (1.83; 2.35)

Family history of alcohol problems (parents/siblings)

1.48 (1.25; 1.75)

Family history of drug problems (parents/siblings)

1.52 (1.22; 1.89)

Model 2: cannabis use*

Days of cannabis use/month, IRR (95% CI)

Perception of cannabis use of others (same age/sex), reference group = accurate estimation of cannabis use of others

 

Overestimation of cannabis use by others

1.43 (1.21; 1.70)

Underestimation of cannabis use by others

0.62 (0.23; 0.75)

Close friends with alcohol or drug problems

2.91 (2.48; 3.42)

Family history of alcohol problems (parents/siblings)

1.12 (0.89; 1.42)

Family history of drug problems (parents/siblings)

1.78 (1.36; 2.33)

Model 3: drinking*

Drinks/week, IRR (95% CI)

Perception of drinking of others (same age/sex), reference group = accurate estimation of drinking of others

 

Overestimation of drinking of others

1.57 (1.43; 1.72)

Underestimation of drinking of others

0.41 (0.34; 0.50)

Close friends with alcohol or drug problems

1.43 (1.28; 1.59)

Family history of alcohol problems (parents/siblings)

1.35 (1.17; 1.55)

Family history of drug problems (parents/siblings)

1.38 (1.14; 1.67)

  1. *All models were adjusted for age, education level, and linguistic region. IRR = incidence rate ratio.