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 .
Association of the mu-opioid receptor gene with smoking cessation
We investigated the association of the OPRM1 genotype with  long-term smoking cessation and  change in body mass index ( BMI ) following a smoking cessation attempt among smokers who attempted to quit using the nicotine replacement therapy ( NRT ) patch or placebo in a r and omized controlled trial , and were followed-up over an 8-year period following their initial cessation attempt . We also investigated possible sex differences in these relationships , given evidence for sex differences in smoking cessation and central opioid mechanisms , as well as some evidence for sex differences in response to NRT . Our results indicate that OPRM1 genotype may moderate the effect of  transdermal nicotine patch compared to placebo during active treatment , with a benefit of active NRT treatment evident in the OPRM1 AA genotype group only and those carrying one or more copies of the G allele demonstrating no benefit of active NRT versus placebo patch . Our results also indicate a sex difference in change in BMI at 8-year follow-up following a smoking cessation attempt , with ex-smokers demonstrating an increase in BMI , and this increase being greater in female subjects than in male subjects . We did not observe any association of OPRM1 genotype with change in BMI , although there was a trend for genotype to influence the observed sex difference in change in BMI over time . Future studies should attempt to replicate these findings , and investigate the relationship between both short- and long-term weight gain and smoking cessation and investigate possible mechanisms that may underlie these processes . Future studies should also investigate the role of OPRM1 genotype and smoking cessation on other appetitive and reward behaviours such as alcohol consumption
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 .