Publications (43)186.48 Total impact
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Article: The Twin Research Registry at SRI International.
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ABSTRACT: The Twin Research Registry (TRR) at SRI International is a community-based registry of twins established in 1995 by advertising in local media, mainly on radio stations and in newspapers. As of August 2012, there are 3,120 same- and opposite-sex twins enrolled; 86% are 18 years of age or older (mean age 44.9 years, SD 16.9 years) and 14% less than 18 years of age (mean age 8.9 years, SD 4.5); 67% are female, and 62% are self-reported monozygotic (MZ). More than 1,375 twins have participated in studies over the last 15 years in collaboration with the University of California Medical Center in San Francisco, the University of Texas MD Anderson Cancer Center, and the Stanford University School of Medicine. Each twin completes a registration form with basic demographic information either online at the TRR Web site or during a telephone interview. Contact is maintained with members by means of annual newsletters and birthday cards. The managers of the TRR protect the confidentiality of twin data with established policies; no information is given to other researchers without prior permission from the twins; and all methods and procedures are reviewed by an Institutional Review Board. Phenotypes studied thus far include those related to nicotine metabolism, mutagen sensitivity, pain response before and after administration of an opioid, and a variety of immunological responses to environmental exposures, including second-hand smoke and vaccination for seasonal influenza virus and Varicella zoster virus. Twins in the TRR have participated in studies of complex, clinically relevant phenotypes that would not be feasible to measure in larger samples.Twin Research and Human Genetics 10/2012; · 1.70 Impact Factor -
Article: Differences in time to onset of smoking and nicotine dependence by race/ethnicity in a Midwestern sample of adolescents and young adults from a high risk family study.
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ABSTRACT: The objective of this study was to determine whether race/ethnicity was associated with time to smoking initiation and time from first cigarette to onset of DSM-IV nicotine dependence (ND) after adjusting for familial and individual psychosocial risk factors. Cox proportional hazards models with time-dependent covariates were used to analyze data from 1376 offspring aged 12-33 years from 532 families at high risk for substance use problems due to paternal alcohol problems and 235 low risk families. Fifty-six percent of the sample self-identified as African-American (AA) and 44% were mainly of European descent. Controlling for covariates, AAs began smoking at older ages (HR=0.58; 95% CI: 0.48-0.70) and had longer times between smoking initiation and onset of ND compared to non-AAs (HR=0.25, 95% CI: 0.16-0.39 for ND onset occurring <18 years and HR=0.49, 95% CI: 0.30-0.80 for ND onsets ≥ age 18). After additionally controlling for number of cigarettes smoked daily, the racial/ethnic effects for onset of ND were attenuated, but remained statistically significant for ND onset <18 (HR=0.34, 95% CI: 0.19-0.61); however, the estimate was no longer significant for later ND onset (HR=0.84, 95% CI: 0.50-1.41). AA adolescents and young adults initiate smoking at older ages and have longer transition periods between initiation and onset of ND compared to non-AAs, even after controlling for many relevant psychiatric and psychosocial covariates; however, racial/ethnic differences in time to onset of nicotine dependence in late adolescence and young adulthood may be explained by differences in daily quantity smoked.Drug and alcohol dependence 05/2012; 125(1-2):140-5. · 3.60 Impact Factor -
Article: Longitudinal genetic analysis of brain volumes in normal elderly male twins.
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ABSTRACT: This study investigated the role of genetic and environmental influences on individual differences in brain volumes measured at 2 time points in normal elderly males from the National Heart, Lung, and Blood Institute Twin Study. The magnetic resonance imaging (MRI) scans were conducted 4 years apart on 33 monozygotic and 33 dizygotic male twin pairs, aged 68 to 77 years when first scanned. Volumetric measures of total brain and total cerebrospinal fluid were significantly heritable at baseline (over 70%). For both volumes genetic influences at follow-up were entirely accounted for by genetic influences at baseline, suggesting that the same genetic factors influence variability in brain volume at each time of assessment. Variability in 4-year volume change was due to shared and individual-specific environmental influences. There was little evidence for heritable influences on change measures. These results suggest that variation in longitudinal change of some brain volume measures may have different underlying genetic and environmental architecture from variation in repeat cross-sectional measures, which could have implications for intervention strategies for age-related illness associated with brain morphology. The results of this study are discussed in the context of the small sample size and associated limitations of statistical power.Neurobiology of aging 04/2012; 33(4):636-44. · 5.94 Impact Factor -
Article: Genetic influences on developmental smoking trajectories.
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ABSTRACT: To investigate the relative contribution of genetic and environmental factors on smoking trajectory membership and to test whether individual smoking trajectories represent phenotypical thresholds of increasing genetic risk along a common genetic liability dimension. Prospective study of a birth cohort of female like-sex twin pairs. Participants completed diagnostic interview surveys four times from adolescence (average age 16) to young adulthood (average age 25). Female twins who had smoked ≥100 cigarettes life-time (n = 1466 regular smokers). Number of cigarettes smoked per day during the heaviest period of smoking (two waves) or during the past 12 months (two waves). A four-trajectory class solution provided the best fit to cigarette consumption data and was characterized by low (n = 564, 38.47%), moderate (n = 366, 24.97%) and high-level smokers (n = 197, 13.44%), and smokers who increased their smoking from adolescence to young adulthood (n =339, 23.12%). The best genetic model fit was a three-category model that comprised the low, a combined increasing + moderate and high trajectories. This trajectory categorization was heritable (72.7%), with no evidence for significant contribution from shared environmental factors. The way in which smoking patterns develop in adolescence has a high level of heritability.Addiction 03/2012; 107(9):1696-704. · 4.31 Impact Factor -
Article: Nature versus nurture in gout: a twin study.
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ABSTRACT: Gouty arthritis (gout) is the most common inflammatory arthritis in the United States and several other countries. Some rare forms of gout have a known genetic basis, but the relative importance of genetic factors on the risk for the lifetime prevalence of gout is not clear. We performed a heritability analysis for hyperuricemia and gout among 514 unselected, all-male twin pairs who were a part of the National Heart, Lung, and Blood Institute twin study, a prospective observational cohort study. Statistical analyses were performed using structural equation models and maximum likelihood methods. The covariates used for adjustment in the structural equation models were identified using bivariate logistic regressions. The study population included 253 monozygotic (MZ) and 261 dizygotic (DZ) twin pairs, aged 48 (±3) years at baseline and followed for a mean of 34 years. The lifetime prevalence of gout did not differ between MZ and DZ twins. The concordance of hyperuricemia was 53% in MZ and 24% in DZ twin pairs (P<.001). Models that quantified the relative contribution of genetic and environmental factors on phenotypic variance showed that individual variability in gout was substantially influenced by environmental factors shared between co-twins and not by genetic factors. In contrast, individual differences in hyperuricemia were influenced significantly by genetic factors. Hyperuricemia is a genetic trait. Outside the context of rare genetic disorders, risk for gout is determined by the environment. This has implications for prevention and treatment approaches.The American journal of medicine 02/2012; 125(5):499-504. · 4.47 Impact Factor -
Article: Functional neuroimaging study in identical twin pairs discordant for regular cigarette smoking.
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ABSTRACT: Despite the tremendous public health and financial burden of cigarette smoking, relatively little is understood about brain mechanisms that subserve smoking behavior. This study investigated the effect of lifetime regular smoking on brain processing in a reward guessing task using functional magnetic resonance imaging and a co-twin control study design in monozygotic (MZ) twin pairs that maximally controls for genetic and family background factors. Young adult (24-34 years) MZ female twin pairs (n = 15 pairs), discordant for regular smoking defined using Centers for Disease Control criteria as having smoked ≥100 cigarettes in their lifetime, were recruited from an ongoing genetic epidemiological longitudinal study of substance use and psychopathology. We applied hypothesis-driven region of interest (ROI) and whole-brain analyses to investigate the effect of regular smoking on reward processing. Reduced response to reward and punishment in regular compared with never-regular smokers was seen in hypothesis-driven ROI analysis of bilateral ventral striatum. Whole-brain analysis identified bilateral reward-processing regions that showed activation differences in response to winning or losing money but no effect of regular smoking; and frontal/parietal regions, predominantly in the right hemisphere, that showed robust effect of regular smoking but no effect of winning or losing money. Altogether, using a study design that maximally controls for group differences, we found that regular smoking had modest effects on striatal reward processing regions but robust effects on cognitive control/attentional systems.Addiction Biology 02/2012; · 4.83 Impact Factor -
Article: Smokefree community policies promote home smoking bans. Unknown mechanisms and opportunities for preventive medicine.
American journal of preventive medicine 12/2011; 41(6):650-2. · 4.24 Impact Factor -
Article: Sensitivity to secondhand smoke exposure predicts future smoking susceptibility.
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ABSTRACT: Susceptibility to cigarette smoking in tobacco-naive youth is a strong predictor of smoking initiation. Identifying mechanisms that contribute to smoking susceptibility provide information about early targets for smoking prevention. This study investigated whether sensitivity to secondhand smoke exposure (SHSe) contributes to smoking susceptibility. Subjects were high-risk, ethnically diverse 8- to 13-year-old subjects who never smoked and who lived with at least 1 smoker and who participated in a longitudinal SHSe reduction intervention trial. Reactions (eg, feeling dizzy) to SHSe were assessed at baseline, and smoking susceptibility was assessed at baseline and 3 follow-up measurements over 12 months. We examined the SHSe reaction factor structure, association with demographic characteristics, and prediction of longitudinal smoking susceptibility status. Factor analysis identified "physically unpleasant" and "pleasant" reaction factors. Reported SHSe reactions did not differ across gender or family smoking history. More black preteens reported feeling relaxed and calm, and fewer reported feeling a head rush or buzz compared with non-Hispanic white and Hispanic white counterparts. Longitudinally, 8.5% of subjects tracked along the trajectory for high (versus low) smoking susceptibility. Reporting SHSe as "unpleasant or gross" predicted a 78% reduction in the probability of being assigned to the high-smoking susceptibility trajectory (odds ratio: 0.22 [95% confidence interval: 0.05-0.95]), after covariate adjustment. Assessment of SHSe sensitivity is a novel approach to the study of cigarette initiation etiology and informs prevention interventions.PEDIATRICS 08/2011; 128(2):254-62. · 4.47 Impact Factor -
Article: The relationship between rs3779084 in the dopa decarboxylase (DDC) gene and alcohol consumption is mediated by drinking motives in regular smokers.
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ABSTRACT: Motivational models of alcohol use propose that the motivation to consume alcohol is the final common pathway to its use. Both alcohol consumption and drinking motives are influenced by latent genetic factors that partially overlap. This study investigated whether drinking motives mediate the associations between alcohol consumption and 2 single-nucleotide polymorphisms (SNPs) from genes involved in serotonin (TPH2; rs1386496) and dopamine synthesis (DDC; rs3779084). Based on earlier work showing that enhancement and coping motives were heritable in regular smokers but not in nonregular smokers, we hypothesized these motives would mediate the relationships between alcohol consumption and these SNPs in regular smokers. Drinking motives data were available from 830 young adult female twins (n = 344 regular smokers and n = 486 never/nonregular smokers). We used confirmatory factor analyses to model enhancement, coping, and alcohol consumption factors and to conduct mediation analyses in the regular smoker and never/nonregular smoker groups. Our hypothesis was partially supported. The relationship between alcohol consumption and rs1386496 was not mediated by drinking motives in either group. However, in the regular smokers, the relationship between alcohol consumption and rs3779084 was mediated by enhancement and coping motives. Carriers of the rs3779084 minor allele who were regular smokers reported more motivation to consume alcohol. Given this pattern of results was absent in the never/nonregular smokers, our results are consistent with a gene × smoking status interaction. In regular smokers, variability at the locus marked by rs3779084 in the DDC gene appears to index biologically based individual differences in the motivation to consume alcohol to attain or improve a positive affective state or to relieve a negative one. These results could be because of increased sensitivity to the reinforcing effects of alcohol among minor allele carriers who smoke, which might be due to structural or functional differences in mesorticolimic dopamine "reward" circuitry.Alcoholism Clinical and Experimental Research 07/2011; 36(1):162-70. · 3.34 Impact Factor -
Article: Heritability of smoking, alcohol use, and psychological characteristics among adolescent twins in Qingdao, China.
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ABSTRACT: Previous studies of genetic and environmental influences on adolescent substance use have been limited to Western samples. This study assesses genetic and environmental contributions to cigarette smoking, alcohol use, and psychological variables (depression, anxiety, aggression, hostility) among 602 pairs of adolescent twins, 11 to 19 years old, in Qingdao, China. Heritable influences were more pronounced for alcohol use than cigarette smoking. In univariate analyses, no heritable effects were found for depression or aggression, and modest heritability was found for anxiety. Hostility was relatively more heritable in girls than boys. Bivariate associations between substance use and psychological measures could be attributed to a combination of common genetic and environmental factors. Among Chinese adolescents, experimentation with tobacco is familial, and experimentation with alcohol is heritable. The genetic and environmental architecture of hostility differs by gender. Consistency of univariate results with Western adolescent samples appears limited to the alcohol use measures.Asia-Pacific Journal of Public Health 07/2011; 23(4):568-80. · 1.06 Impact Factor -
Article: Providing coaching and cotinine results to preteens to reduce their secondhand smoke exposure: a randomized trial.
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ABSTRACT: Secondhand smoke exposure (SHSe) poses health risks to children living with smokers. Most interventions to protect children from SHSe have coached adult smokers. This trial determined whether coaching and cotinine feedback provided to preteens can reduce their SHSe. Two hundred one predominantly low-income families with a resident smoker and a child aged 8 to 13 years who was exposed to two or more cigarettes per day or had a urine cotinine concentration ≥ 2.0 ng/mL were randomized to control or SHSe reduction coaching groups. During eight in-home sessions over 5 months, coaches presented to the child graphic charts of cotinine assay results as performance feedback and provided differential praise and incentives for cotinine reductions. Generalized estimating equations were used to determine the differential change in SHSe over time by group. For the baseline to posttest period, the coaching group had a greater decrease in both urine cotinine concentration (P = .039) and reported child SHSe in the number of cigarettes exposed per day (child report, P = .003; parent report, P = .078). For posttest to month 12 follow-up, no group or group by time differences were obtained, and both groups returned toward baseline. Coaching preteens can reduce their SHSe, although reductions may not be sustained without ongoing counseling, feedback, and incentives. Unlike interventions that coach adults to reduce child SHSe, programs that increase child avoidance of SHSe have the potential to reduce SHSe in all settings in which the child is exposed, without requiring a change in adult smoking behavior.Chest 04/2011; 140(3):681-9. · 5.25 Impact Factor -
Article: Sensitivity to secondhand smoke exposure predicts smoking susceptibility in 8-13-year-old never smokers.
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ABSTRACT: To investigate the sensitivity to secondhand smoke exposure (SHSe) in preteens aged 8-13 years who have never smoked, and to determine whether it predicts smoking susceptibility. We assessed the sensitivity to SHSe using reactions commonly used for the assessment of sensitivity to the first-smoked cigarette (e.g., feeling dizzy), and investigated the factor structure of these reactions for the purpose of data reduction. We examined the association of each reaction measure and summary score with demographic characteristics and smoking susceptibility, using logistic regression and ordinal logistic regression. One factor was identified that captured the physical and/or unpleasant reactions. Older preteens and preteens with more highly educated parents reported fewer reactions to SHSe. More African American preteens reported feeling relaxed or calm compared with all other racial/ethnic groups. Experiencing physical and/or unpleasant reactions to SHSe predicted lower risk for smoking susceptibility. This was the first study to extend analytical methodology for sensitivity to active smoking to sensitivity to SHSe in youth who had never smoked. Results suggest a desensitization process with age and lower sensitivity to some reactions in preteens from more highly educated households. Preteens who have more aversive experiences with SHSe tend to be less susceptible to smoking than those who experience fewer aversive reactions. Assessment of sensitivity to SHSe is a novel approach to the study of cigarette use etiology and may contribute to better prediction of smoking initiation.Journal of Adolescent Health 03/2011; 48(3):234-40. · 3.33 Impact Factor -
Article: Smoking outcome expectancies in young adult female smokers: individual differences and associations with nicotine dependence in a genetically informative sample.
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ABSTRACT: Outcome expectancy is a central construct in models of addiction. Several outcome expectancies associated with smoking cigarettes have been identified, and studies suggest that individual differences in smoking expectancies are related to important aspects of tobacco use, including levels of smoking, nicotine dependence and smoking cessation. In the present study, we used a novel analytic method, exploratory structural equation modeling (ESEM), to quantify smoking expectancies from a subset of items adapted from the Smoking Consequences Questionnaire (SCQ; Brandon and Baker, 1991) and SCQ-Adult (Copeland et al., 1995). In our sample of 1262 monozygotic and dizygotic young adult, female twins who were regular smokers, we quantified six smoking expectancy factors similar to those reported in previous studies. These included Negative Affect Reduction, Boredom Reduction, Weight Control, Taste Manipulation, Craving/Addiction and Stimulation-state Enhancement. We used genetic model-fitting to examine the extent to which individual differences in the expectancies were influenced by latent genetic, shared environmental and non-shared environmental factors. We also examined the validity of the expectancy factors by examining their associations with nicotine dependence (ND) before and after adjusting for comorbid diagnoses of drug dependence and alcohol use disorder. Results of the validity analysis indicated that all of the expectancies were associated with ND after covariate adjustment. Although we lacked the statistical power to distinguish between genetic and shared environmental sources of variance, our results suggest that smoking outcome expectancies aggregate in families, but the majority of variance in these expectancies is due to environmental factors specific to the individual.Drug and alcohol dependence 12/2010; 116(1-3):37-44. · 3.60 Impact Factor -
Article: Body mass index and regular smoking in young adult women.
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ABSTRACT: Little is known about the relationship between relative body weight and transition from experimentation to regular smoking in young adult women. In the current study, data from 2494 participants in wave 4 of the Missouri Adolescent Female Twin Study (aged 18-29years) who reported ever smoking a cigarette were analyzed using logistic regression. Body mass index (BMI) at time of interview was categorized according to CDC adult guidelines, and regular smoking was defined as having ever smoked 100 or more cigarettes and having smoked at least once a week for two months in a row. Since the OR's for the overweight and obese groups did not differ significantly from one another in any model tested, these groups were combined. Forty-five percent of women who had ever smoked had become regular smokers. Testing of interactions between potential covariates and levels of the categorical BMI variable revealed a significant interaction between overweight/obesity and childhood sexual abuse (CSA; p<0.001) associated with regular smoking. Among women reporting CSA, the association between overweight/obesity and having become a regular smoker was negative (n=374; OR=0.48, 95% CI: 0.28-0.81). Both underweight and overweight/obesity were positively associated with transition to regular smoking among women who did not report CSA (n=2076; OR=1.57, 95% CI: 1.05-2.35 and OR=1.73, 95% CI: 1.35-2.20, respectively). These results suggest that experiencing CSA alters the association between BMI and regular smoking in women who have experimented with cigarettes.Addictive behaviors 11/2010; 35(11):983-8. · 2.25 Impact Factor -
Article: Drinking motives in female smokers: factor structure, alcohol dependence, and genetic influences.
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ABSTRACT: Alcohol and tobacco use often co-occur. Human and animal studies indicate that nicotine increases alcohol's rewarding effects and the motivation to consume it. The aims of this study were to examine whether the factorial architecture of self-reported motivations to consume alcohol differed between regular and nonregular cigarette smokers while taking into account the lifetime history of alcohol dependence and psychopathology, and to estimate the genetic and environmental influences on the motivations. Using data on 2,189 monozygotic and dizygotic female twins, we examined the factorial structure (item thresholds and factor loadings, means, and variances) of the items from the Drinking Motives Questionnaire (DMQ) in regular and nonregular smokers. Post hoc tests examined the association between the latent drinking motives factors and alcohol dependence in both groups. Twin models were fitted to the latent drinking motives factors, testing for variations in the magnitude of additive genetic, shared, and nonshared environmental influences between the groups. The 4 DMQ factors (social, conformity, coping, and enhancement) were recovered in both groups, and their measurement structure was consistent across the groups. Regular smokers reported higher levels of coping, enhancement, and social motives while nonregular smokers reported higher conformity motives. Alcohol dependence was associated with higher scores on all motives in both groups; however, in a regression analysis that included all of the motives as predictor variables, only coping was significantly related to alcohol dependence. While twin models revealed evidence for substantially greater genetic influences on enhancement (h² = 0.40), coping (h² = 0.35) and social (h² = 0.37) drinking motives in regular compared to nonregular smokers, the power to statistically distinguish the 2 groups was low. While the measurement structure of the drinking motive factors appears to be similar across regular and nonregular smokers, regular smokers report more motivation to drink for internal affect-related reasons and to obtain social reward. Of all the motives, coping was the most robust predictor of alcohol dependence in both the regular and the nonregular smokers. Further, genetic influences might play a larger role in drinking motives among regular smokers, which provides tentative evidence for latent genetic × smoking status interactions.Alcoholism Clinical and Experimental Research 11/2010; 35(2):345-54. · 3.34 Impact Factor -
Article: Validity of recall of tobacco use in two prospective cohorts.
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ABSTRACT: This project studied the convergent validity of current recall of tobacco-related health behaviors, compared with prospective self-report collected earlier at two sites. Cohorts were from the Oregon Research Institute at Eugene (N = 346, collected 19.5 years earlier) and the University of Pittsburgh, Pennsylvania (N = 294, collected 3.9 years earlier). Current recall was examined through computer-assisted interviews with the Lifetime Tobacco Use Questionnaire from 2005 through 2008. Convergent validity estimates demonstrated variability. Validity estimates of some tobacco use measures were significant for Oregon subjects (age at first cigarette, number of cigarettes/day, quit attempts yes/no and number of attempts, and abstinence symptoms at quitting; all P < 0.03). Validity estimates of Pittsburgh subjects' self-reports of tobacco use and abstinence symptoms were significant (P < 0.001) for all tobacco use and abstinence symptoms and for responses to initial use of tobacco. These findings support the utility of collecting recalled self-report information for reconstructing salient lifetime health behaviors and underscore the need for careful interpretation.American journal of epidemiology 10/2010; 172(7):828-35. · 5.59 Impact Factor -
Article: Prediction of individual brain maturity using fMRI.
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ABSTRACT: Group functional connectivity magnetic resonance imaging (fcMRI) studies have documented reliable changes in human functional brain maturity over development. Here we show that support vector machine-based multivariate pattern analysis extracts sufficient information from fcMRI data to make accurate predictions about individuals' brain maturity across development. The use of only 5 minutes of resting-state fcMRI data from 238 scans of typically developing volunteers (ages 7 to 30 years) allowed prediction of individual brain maturity as a functional connectivity maturation index. The resultant functional maturation curve accounted for 55% of the sample variance and followed a nonlinear asymptotic growth curve shape. The greatest relative contribution to predicting individual brain maturity was made by the weakening of short-range functional connections between the adult brain's major functional networks.Science 09/2010; 329(5997):1358-61. · 31.20 Impact Factor -
Article: Initial response to cigarettes predicts rate of progression to regular smoking: findings from an offspring-of-twins design.
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ABSTRACT: The aim of this study was to examine the association between initial subjective effects from cigarettes and the rate of progression from first cigarette to regular smoking. Latent class analysis (LCA) was applied to subjective effects data from 573 offspring of twins ranging in age from 14 to 32 years. LCA revealed four classes: 1) High on both pleasurable and physiological responses, 2) Cough only response, 3) High on physiological, low on pleasurable responses, and 4) High on pleasurable, low on physiological responses. Classes of responses were then used to predict time from first cigarette to the onset of regular smoking in a Cox proportional hazards model. Time-varying covariates representing relevant psychiatric and psychosocial factors as well as dummy variables representing the offspring-of-twins design were included in the model. Members of classes 1 and 4 transitioned more rapidly to regular smoking than the classes characterized as low on the pleasurable response dimension. Our findings provide evidence that previously reported associations between pleasurable initial experiences and progression to regular smoking hold true as well for the rate at which that transition occurs. Furthermore, the fact that profiles of responses did not fall into global categories of exclusively pleasurable vs. exclusively negative (physiological) responses suggests the importance of considering both dimensions in combination to characterize risk for smoking-related outcomes.Addictive behaviors 03/2010; 35(8):771-8. · 2.25 Impact Factor -
Article: Nicotine addiction in light smoking African American mothers.
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ABSTRACT: Although African Americans (AA) smoke fewer average cigarettes per day (CPD) than European Americans (EA), they carry a disproportionate tobacco related morbidity and mortality burden. To evaluate ethnic differences in markers of nicotine addiction, including rates of lifetime nicotine dependence (ND) symptoms, current smoking and smoking during pregnancy across different levels of peak lifetime cigarette consumption. Data from 237 EA (N=118) and AA (N=119) mothers participating in the Missouri Family Study (2003-2005), an ethnically diverse family study of offspring outcomes in high and low risk families, were used to contrast prevalence of ND symptoms and other smoking behaviors between EA and AA women at low (1-10 CPD), moderate (11-19 CPD), and high (≥ 20 CPD) levels of lifetime peak daily cigarette consumption. Compared with EA smokers, AAs had lower lifetime prevalence of DSM-IV ND (68% v. 54%, p<.05), consumed fewer CPD during their heaviest lifetime consumption (18% EA v. 58% AA smoked ≤ 10 CPD, p<.0001), but did not differ in overall rates of smoking during pregnancy or current smoking. However, stratifying by categories of peak lifetime daily cigarette use, AA mothers who smoked ≤ 10 CPD reported greater lifetime ND symptoms and current smoking than their EA counterparts. In addition, nearly two-thirds of AA mothers in this smoking category smoked during pregnancy and 30% smoked throughout an entire pregnancy. The respective prevalence estimates in EA mothers were 38% and 0%. Stratifying the sample into categories of lifetime peak daily cigarette use revealed significant ethnic/racial differences in smoking prevalence during pregnancy that were obscured in overall analysis. Substantial public health risks warranting clinical attention exist among light smokers, particularly AA women.Journal of Addiction Medicine 03/2010; 4(1):55-60. · 1.95 Impact Factor -
Article: Genetic influences on individual differences in nicotine glucuronidation.
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ABSTRACT: Nicotine and its primary oxidative metabolites are metabolized in part by glucuronidation. Genetic variation in UGT isoenzymes that catalyze glucuronidation activity suggests that variation in glucuronidation rate is in part genetically determined. The relative contribution of genetic and environmental sources to individual differences in the rate of glucuronidation of nicotine, cotinine, and trans-3'-hydroxycotinine was estimated in a twin study of nicotine pharmacokinetics. Glucuronidation rate was defined using measures that either accounted for variability in renal clearance or assumed the same relative renal clearance of parent drug and glucuronide conjugate across individuals. The former definition resulted in highly correlated nicotine and cotinine glucuronidation measures that were substantially influenced by the combined effect of additive (heritable) and non-additive (dominant and epistatic) genetic effects. These findings suggest that genetic variation in UGT isoenzymes that act in additive and interactive ways is an important determinant of individual variability in nicotine and cotinine metabolism via glucuronidation pathways.Twin Research and Human Genetics 10/2009; 12(5):507-13. · 1.70 Impact Factor
Top co-authors
Top Journals
Institutions
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2012
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Stanford University
- Division of Rheumatology
Palo Alto, CA, USA -
National Institute of Mental Health (NIMH)
Bethesda, MD, USA
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2011–2012
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University of Washington Seattle
- Division of General Internal Medicine
Seattle, WA, USA
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2008–2012
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SRI International
- Centre for Health Sciences
Menlo Park, CA, USA -
Washington University in St. Louis
- Department of Psychiatry
Saint Louis, MO, USA
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2010
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Yale University
- Department of Psychiatry
New Haven, CT, USA
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