Relative contribution of genetic, individual, and self-efficacy factors to smoking cessation in a Chinese rural population.

BACKGROUND AND OBJECTIVES: Nicotine dependence is influenced by genetic, individual, and psychological factors. We aimed to examine whether nicotinic acetylcholine receptor genes (CHRN) were associated with smoking cessation (SC) using genetic risk score and compare the relative contribution of genetic, individual and self-efficacy factors to SC. METHODS: Eight hundred and nineteen male smokers (mean age: 59.62) were recruited from 17 villages of three counties in Shandong province, China. Thirty-two single nucleotide polymorphisms (SNPs) in seven CHRN genes were genotyped. Logistic regression was used to explore the relationship between genetic risk score and SC. Dominance analysis was performed to compare the relative contribution of genetic, individual, and self-efficacy factors on SC. RESULTS: CHRNA3 genetic risk score was associated with SC. Dominance analysis showed that individual factor was the most important predictor for SC, followed by genetic and self-efficacy factors. CONCLUSIONS: CHRNA3 was associated with successful SC. Individual factor had more contribution than genetic factor to SC. SCIENTIFIC SIGNIFICANCE: Our findings provide support to the role of CHRN genes in the etiology of smoking cessation using genetic risk score. Individual factor should be particularly valued in smoking control intervention. (Am J Addict 2017;26:161-166).

The association of environmental, individual factors, and dopamine pathway gene variation with smoking cessation.

This study aimed to examine whether dopamine (DA) pathway gene variation were associated with smoking cessation, and compare the relative importance of infulence factors on smoking cessation. Participants were recruited from 17 villages of Shandong Province, China. Twenty-five single nucleotide polymorphisms in 8 DA pathway genes were genotyped. Weighted gene score of each gene was used to analyze the whole gene effect. Logistic regression was used to calculate odds ratios (OR) of the total gene score for smoking cessation. Dominance analysis was employed to compare the relative importance of individual, heaviness of smoking, psychological and genetic factors on smoking cessation. 415 successful spontaneous smoking quitters served as the cases, and 404 unsuccessful quitters served as the controls. A significant negative association of total DA pathway gene score and smoking cessation was observed (p < 0.001, OR: 0.25, 95% CI 0.16-0.38). Dominance analysis showed that the most important predictor for smoking cessation was heaviness of smoking score (42%), following by individual (40%), genetic (10%) and psychological score (8%). In conclusion, although the DA pathway gene variation was significantly associated with successful smoking cessation, heaviness of smoking and individual factors had bigger effect than genetic factors on smoking cessation.

Association between variants in nicotinic acetylcholine receptor genes and smoking cessation in a Chinese rural population.

BACKGROUND AND OBJECTIVES: Genetic studies have revealed a significant association between variants in nicotinic acetylcholine receptor (CHRN) genes and smoking cessation, but the results are inconsistent. In this study, we aimed to examine the relationship between single nucleotide polymorphisms (SNPs) in seven CHRN genes and smoking cessation in a Chinese rural population. METHODS: Participants were recruited from 17 villages of 3 counties in Shandong, China. DNA was extracted from the blood samples. Thirty-two SNPs in seven CHRN genes were genotyped. Logistic regression was used to explore the relationship between single SNP and smoking cessation. Pearson's χ(2) test was performed to test the association between haplotype and smoking cessation. RESULTS: Rs578776 (in CHRNA3), rs660652 (in CHRNA3), and rs588765 (in CHRNA5) were significantly related to smoking cessation. Two haplotypes were associated with smoking cessation. CONCLUSIONS: This study confirmed the association between CHRN genes and smoking cessation in the Chinese rural population. SCIENTIFIC SIGNIFICANCE: Our findings provide confirmatory support to the role of CHRN genes to the etiology of smoking cessation in the Chinese rural population. (Am J Addict 2016;25:297-300).

The association of dopamine pathway gene score, nicotine dependence and smoking cessation in a rural male population of Shandong, China.

BACKGROUND AND OBJECTIVES: Smoking and smoking cessation are both psychological and physiological traits. We aimed to investigate the interaction between dopamine pathway gene scores and nicotine dependence on smoking cessation in a rural Chinese male population. METHODS: Participants were recruited from 17 villages in Shandong, China. DNA was extracted from blood sample of 819 participants. 25 single nucleotide polymorphisms (SNPs) in 8 dopamine (DA) pathway genes were genotyped. Weighted gene score of each gene is used to analyze the whole gene effect. Logistic regression was used to calculate odds ratios (OR) and multivariate-adjusted OR of each gene score for smoking cessation. Multiplicative model interaction was assessed through a cross-product interaction term of gene score by nicotine dependence in a multivariate logistic regression model. RESULTS: After adjusting for age, occupation, education, marital status, self-rating anxiety score, and disease status, we observed significant negative associations of catechol-O-methyltransferase (COMT), dopamine receptor D2 (DRD2) gene score and smoking cessation, as well as significant positive associations between ankyrin repeat and kinase domain containing 1 (ANKK1), dopamine transporter (SLC6A3), dopamine receptor D4 (DRD4) gene score and smoking cessation. A significant multiplicative model interaction between nicotine dependence and the SLC6A3 gene score on smoking cessation was also observed (p = .03). CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE: There is a significant multiplicative model interaction of SLC6A3 gene score and nicotine dependence on smoking cessation. This finding could help to identify smokers who may be at high risk of relapse, and thus to develop more professional and personalized smoking cessation treatment. (Am J Addict 2016;25:493-498).

Assessment of successful smoking cessation by psychological factors using the Bayesian network approach.

The association between psychological factors and smoking cessation is complicated and inconsistent in published researches, and the joint effect of psychological factors on smoking cessation is unclear. This study explored how psychological factors jointly affect the success of smoking cessation using a Bayesian network approach. A community-based case control study was designed with 642 adult male successful smoking quitters as the cases, and 700 adult male failed smoking quitters as the controls. General self-efficacy (GSE), trait coping style (positive-trait coping style (PTCS) and negative-trait coping style (NTCS)) and self-rating anxiety (SA) were evaluated by GSE Scale, Trait Coping Style Questionnaire and SA Scale, respectively. Bayesian network was applied to evaluate the relationship between psychological factors and successful smoking cessation. The local conditional probability table of smoking cessation indicated that different joint conditions of psychological factors led to different outcomes for smoking cessation. Among smokers with high PTCS, high NTCS and low SA, only 36.40% successfully quitted smoking. However, among smokers with low pack-years of smoking, high GSE, high PTCS and high SA, 63.64% successfully quitted smoking. Our study indicates psychological factors jointly influence smoking cessation outcome. According to different joint situations, different solutions should be developed to control tobacco in practical intervention.

Mediation of smoking abstinence self-efficacy on the association of nicotine dependence with smoking cessation.

BACKGROUND: The nicotine dependence (ND) has negative and smoking abstinence self-efficacy (SASE) has positive effects on successful smoking cessation, but scant data is now available for what is the mediating role of SASE on the relationship between ND and successful smoking cessation. The aim of this study was to assess the abovementioned mediation. METHODS: A case-control study was conducted with 642 successful spontaneous quitters as the cases, and 700 failed spontaneous quitters as the controls. ND and SASE were evaluated by Fagerström Test for Nicotine Dependence (FTND) scale and SASE scale, respectively. Propensity score as covariate in the regression model was used to adjust for potential confounders of age, age of smoking initiation, occupation, educational level and marital status. Total effect was decomposed into direct and indirect (mediating) effect using logistic regression based on the KHB method proposed by Holm et al. RESULTS: After adjusting for the aforementioned potential confounders, the mediating effects among the total effect of ND on successful spontaneous smoking cessation were 32.90%, 12.14%, 35.64% and 83.03% for the total score of SASE and its three context-specific situation scores, i.e. positive/social situation, negative/affective situation and habit/addictive situation, respectively. CONCLUSIONS: This study indicates that SASE has a partial mediating effect on the association of ND with successful spontaneous smoking cessation. To boost the smokers' SASE could increase the probability of successful smoking cessation.

[Association between social support and outcomes as successful smoking cessation in males from the rural areas].

OBJECTIVE: To examine the association between social support and successful smoking cessation outcomes in males from rural areas. METHODS: A community-based case-control study was conducted with 642 adult male cases who appeared to be successful spontaneous smoking quitters as cases, together with other 700 adult males who failed quitting smoking to serve, as controls. Social Support Rating Scale (SSRS) was used to assess the individual social support. Multiple linear method was used to evaluate the relationship between social support and the outcome of successful cessation in smoking. RESULTS: After adjusting the potential confounders as age, education, marital status, profession, age of initial smoking and number of pack-years on smoking, the adjusted mean of subjective social support in successful quitters was significant lower than that in the failed ones (P<0.001). The differences of adjusted means between objective social support and its utility were not statistically different in the two groups among the population who recognized that cigarettes should always be provided when people interact with each other (P=0.124; P=0.763). However, the adjusted means of social support and the related three dimensions did not show significant differences in the two groups among the population in disapproval of the above said social norms (P>0.05). CONCLUSION: Data from our research indicated that social support would negatively affect the successful spontaneous cessation of smoking among people under unhealthy smoking culture.

Association of 5-HTTLPR polymorphism with smoking behaviors: A meta-analysis.

Published articles reported controversial results about the association of 5-HTTLPR polymorphism with the risk of smoking behaviors. A meta-analysis was performed to assess the association between 5-HTTLPR polymorphism and smoking behaviors. A comprehensive search was conducted to identify studies (from January, 1990 to December, 2014) of the aforementioned association. The Q test and the I(2) statistic were used to examine between-study heterogeneity. Fixed or random effect model was selected based on heterogeneity test among studies. Meta-regression was used to explore the potential sources of between-study heterogeneity. Publication bias was estimated using funnel plots and Harbord test. Twenty-one published articles were included. Overall, we didn't find any significant association of 5-HTTLPR polymorphism with smoking initiation and smoking cessation in any of allele, dominant and recessive models. In the subgroup analysis stratified by ethnicity (Caucasian and Asian) or by whether smokers accepted the treatment for smoking cessation or not (Yes/No), there were still no significant associations detected in all genetic models. In conclusion, this meta-analysis suggested that there might be no association of 5-HTTLPR polymorphism with the risk of smoking behaviors. Further studies are needed to confirm these conclusions.

[Mediating effect of smoking abstinence self-efficacy on association between awareness of smoking hazard and successful smoking cessation].

OBJECTIVE: To estimate the mediating effect of smoking abstinence self-efficacy (SASE) on the association between awareness of smoking hazard and successful smoking cessation. METHODS: A community-based case-control study was conducted in 642 smokers who successfully stopped smoking, and 700 smokers who failed in smoking cessation were used as controls. The awareness of smoking hazard was evaluated by total score of 12 items. The SASE was assessed by using Smoking Abstinence Self-Efficacy (ASES-S). The total effect was classified as direct effect and indirect effect through logistic regression analysis based on the KHB method. RESULTS: After adjusting the potential confounders, including age, age of smoking initiation, occupation, educational level and marital status, the mediating effect of SASE accounted for 6.03% among the total effect of awareness of smoking hazard in those who successfully stopped smoking while the direct effect accounted for 93.97% among the total effect. In the three specific situation of SASE, the mediating effect of SASE accounted for 6.80% (positive/social situations), 3.08% (negative/affective situations) and 2.32% (habit/addictive situations) among the total effect, respectively. CONCLUSION: SASE has part mediating effect to influence on the association between the awareness of smoking hazard and successful smoking cessation. Improving smokers' awareness of smoking hazard may not only promote successful smoking cessation directly, but also contribute to quit smoking through improving the score of SASE.

The Relationship between Nicotine Dependence and Age among Current Smokers.

BACKGROUND: A recent study indicates that the incidence of smoking cessation varies with age. Although nicotine dependence (ND) has been regarded as one of the most significant barriers of successful smoking cessation, few researches have focused on the relationship between nicotine dependence and age. METHODS: A cross-sectional study (conducted in 2013) with 596 Chinese rural male current smokers was performed to study the relationship between ND and age. The ND level was assessed using the Fagerström Test for Nicotine Dependence (FTND) scale. The univariate two-degree fractional polynomials (FPs) regression was used to explore the relation of ND to age. RESULTS: The mean of FTND scores in the middle-aged group (45-64 yr old) was higher than that in the younger (<45 yr old) and older groups (≥65 yr old). The FPs regression showed an inverse U-shaped relationship between ND and age. CONCLUSION: The middle-aged current smokers had higher degree of ND than the younger and the older groups, which showed an inverse U-shaped relationship between ND and age. This finding needs to be confirmed by further researches.

[Relationship between age and smoking abstinence self-efficacy].

OBJECTIVE: To investigate the relationship between smoking abstinence self- efficacy (SASE) and age. METHODS: A cross-sectional questionnaire survey in form of face-to-face interview was performed. The SASE level was assessed by using the Smoking Abstinence Self-Efficacy Scale. Univariate two-degree fractional polynomials (FPs) regression model was used to explore the relationship between SASE and age after adjusting of potential confounders: marital status, occupation and education. RESULTS: The relationship between SASE and age showed a U-shaped curve with the nadir at 60 years old. CONCLUSION: The distribution of SASE is not consistent among age groups; middle aged person has lower level of SASE than both the younger and the elder.

[Dominance analysis on the association between reasons for smoking and results related to successful smoking cessation].

OBJECTIVE: To study the association between reasons for smoking and results related to successful smoking cessation. METHODS: A community-based case-control study was conducted with 642 male adults recognized as successful spontaneous smoking quitters being the subject cases while another 700 male adults who had failed to quit smoking were served as the controls. Russell Reason for Smoking Questionnaire (RRSQ) was used to investigate the reasons for smoking. Dominance logistic regression was performed to determine the relative importance of reasons for starting smoking and the endpoint of successful quit smoking. RESULTS: After adjusting the potential confounders of age, age of smoking initiation, marital status, profession, and education, the adjusted means of sedative and stimulation of RRSQ in the successful quitters were significant lower than that in the failed quitters. Results from the dominance logistic regression showed that the first two important factors for smoking cessation were sedative and stimulation of RRSQ, followed by psychological image, automatic, hand-mouth activity, indulgence, and addiction. CONCLUSION: This study demonstrated that factors as dependence-addiction showed more important impacts than the social-psychological ones on the endpoint of successful smoking cessation.