Emotional self-regulation, impulsivity, 5-HTTLPR and tobacco use behavior among psychiatric inpatients.

BACKGROUND: While the serotonin transporter (SLC6A4) gene, 5-HTTLPR, interacts with the social environment to influence both emotional self-regulation and smoking behavior, less is known about interactions between emotional self-regulation and 5-HTTLPR or their joint influence on tobacco use. Here, we examined such interactions among psychiatric inpatients, the population with the highest rates of smoking. METHODS: Participants (506 adults) were psychiatric inpatients at The Menninger Clinic in Houston TX between 2012 and 16. Most were white (89%), male (55%), with a mean age of 32.3 years. Participants completed the Difficulties in Emotional Regulation Scale (DERS) at admission. We examined interactions with smoking among three DERS subscales and 5-HTTLPR, controlling for sex, race and age. RESULTS: Smoking rates were higher among those with the 5-HTTPLR L'L' genotype compared to peers carrying an S' allele (47.9% vs. 37.4%, respectively). Among S' allele carrying participants, impulse control difficulties (OR = 1.09; 95%CI: 1.03-1.14) and lack of emotion clarity (OR = 1.06; 95%CI: 1.00-1.11) increased risk for ever using tobacco, while accessing more ways to regulate emotion (OR = 0.95; 95%CI: 0.92-0.99) offered a protective effect against ever using tobacco. Neither demographic nor DERS covariates were associated with using tobacco among the L'L' group. LIMITATIONS: This ethnically homogenous sample limits generalizability and using a binary outcome can over-estimate a gene environment interaction effect. CONCLUSIONS: Emotional self-regulation exerts a stronger influence on using tobacco among carriers of an S' allele of 5-HTTLPR than peers with the L'L' genotype. Promoting emotional self-regulatory skills may have benefits for preventing tobacco use.

Using the EM algorithm for Bayesian variable selection in logistic regression models with related covariates.

We develop a Bayesian variable selection method for logistic regression models that can simultaneously accommodate qualitative covariates and interaction terms under various heredity constraints. We use expectation-maximization variable selection (EMVS) with a deterministic annealing variant as the platform for our method, due to its proven flexibility and efficiency. We propose a variance adjustment of the priors for the coefficients of qualitative covariates, which controls false-positive rates, and a flexible parameterization for interaction terms, which accommodates user-specified heredity constraints. This method can handle all pairwise interaction terms as well as a subset of specific interactions. Using simulation, we show that this method selects associated covariates better than the grouped LASSO and the LASSO with heredity constraints in various exploratory research scenarios encountered in epidemiological studies. We apply our method to identify genetic and non-genetic risk factors associated with smoking experimentation in a cohort of Mexican-heritage adolescents.

Sensation-seeking genes and physical activity in youth.

Many studies examining genetic influences on physical activity (PA) have evaluated the impact of single nucleotide polymorphisms (SNPs) related to the development of lifestyle-related chronic diseases, under the hypothesis that they would be associated with PA. However, PA is a multidetermined behavior and associated with a multitude of health consequences. Thus, examining a broader range of candidate genes associated with a broader range of PA correlates may provide new insights into the genetic underpinnings of PA. In this study, we focus on one such correlate - sensation-seeking behavior. Participants (N = 1130 Mexican origin youth) provided a saliva sample and data on PA and sensation-seeking tendencies in 2008-2009. Participants were genotyped for 630 functional and tagging variants in the dopamine, serotonin and cannabinoid pathways. Overall 30% of participants (males - 37.6% and females - 22.0%) reported ≥60 min of PA on 5 of 7 days. After adjusting for gender, age and population stratification, and applying the Bayesian False Discovery Probability approach for assessing noteworthiness, four gene variants were significantly associated with PA. In a multivariable model, being male, having higher sensation-seeking tendencies and at least one copy of the minor allele for SNPs in angiotensin I-converting enzyme gene [ACE; rs8066276 odds ratio (OR) = 1.44; P = 0.012] and tryptophan hydroxylase 2 gene (TPH2; rs11615016 OR = 1.73; P = 0.021) were associated with increased likelihood of meeting PA recommendations. Participants with at least one copy of the minor allele for SNPs in synaptosomal-associated protein 25 gene (SNAP25; rs363035 OR = 0.53; P = 0.005) and cannabinoid receptor 1 gene (CNR1; rs6454672 OR = 0.62; P = 0.022) have decreased likelihood of meeting PA recommendations. Our findings extend current knowledge of the complex relationship between PA and possible genetic underpinnings.