Results : We confirmed the importance of the 4 main factors influencing SC : ( 1 ) environmental factors , ( 2 ) genomic factors , ( 3 ) gene-environment interactions , and ( 4 ) evidence -based interventions .
The model demonstrates the complex network of factors influencing SC .
Background : Smoking behaviour is a major public health problem worldwide .
Several sources have confirmed the implication of genomic factors in smoking behaviour .
These factors interact both with environmental factors and interventions to develop a certain behaviour .
Objectives : Describing the environmental and genomic factors as well as the interventions influencing smoking cessation  ( SC ) and developing a working model incorporating the different factors influencing SC were our main objectives .
Role of Functional Genetic Variation in the Dopamine D2 Receptor (DRD2) in Response to Bupropion and Nicotine Replacement Therapy for Tobacco Dependence: Results of Two Randomized Clinical Trials
Although bupropion and nicotine replacement therapy ( NRT ) are efficacious tobacco dependence treatments , there is substantial interindividual variability in therapeutic response and most smokers relapse . Pharmacogenetics research may improve treatment outcomes by identifying genetic variants predictive of therapeutic response . We investigated the roles of two functional genetic variants in the dopamine D2 receptor ( DRD2 ) gene in response to pharmacotherapy for tobacco dependence among participants in two r and omized clinical trials with a 6-month follow-up period : a double-blind placebo-controlled  trial of  bupropion ( n=414 ) and an open label trial of transdermal nicotine vs nicotine nasal spray  ( n=368 ) . At the end of the treatment phase , a statistically significant ( p=0.01 ) interaction between the DRD2 − 141C Ins/Del genotype and treatment indicated a more favorable response to bupropion  among smokers homozygous for the Ins C allele compared to those carrying a Del C allele . By contrast , smokers carrying the Del C allele had statistically significantly ( p=0.006 ) higher quit rates on NRT compared to those homozygous for the Ins C allele , independent of NRT type . The C957 T variant was also associated ( p=0.03 ) with abstinence following NRT . These results suggest that bupropion may be the preferred pharmacologic treatment for smokers homozygous for the DRD2 − 141 Ins C allele , while NRT may be more beneficial for those who carry the Del C allele . Study findings require confirmation in additional larger sample s before they are applied in practice
Results : We confirmed the importance of the 4 main factors influencing SC : ( 1 ) environmental factors , ( 2 ) genomic factors , ( 3 ) gene-environment interactions , and ( 4 ) evidence -based interventions .
The model demonstrates the complex network of factors influencing SC .
Background : Smoking behaviour is a major public health problem worldwide .
Several sources have confirmed the implication of genomic factors in smoking behaviour .
These factors interact both with environmental factors and interventions to develop a certain behaviour .
Objectives : Describing the environmental and genomic factors as well as the interventions influencing smoking cessation  ( SC ) and developing a working model incorporating the different factors influencing SC were our main objectives .