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1.  Self-Rated Health Among Adult Women of Mexican Origin 
Self-rated health (SRH), a consistent predictor of mortality among diverse populations, is sensitive to health indicators and social factors. American-born Hispanics report better SRH than their foreign-born counterparts but simultaneously report poorer health indicators and have shorter life expectancy. Using a matched prospective cross-sectional design, we analyzed data from 631 age-matched pairs of women, born in the United States or Mexico, enrolled in a cohort study based in Houston, Texas. Our first goal was to describe the relationships between SRH and health behaviors, physician-diagnosed chronic conditions, acculturation, and socioeconomic status (SES) by birthplace. Our second goal was to investigate the relative influence of SES, acculturation, health behaviors, and physician-diagnosed conditions in explaining expected differences in SRH between the two groups. Number of chronic conditions reported, particularly depression, more strongly influenced SRH than SES, acculturation, or reported health risk behaviors and the influence of birthplace is accounted for by these factors.
PMCID: PMC3940416  PMID: 24600161
Self-rated health; acculturation; SES; health indicators
2.  Sensation seeking genes and physical activity in youth 
Genes, brain, and behavior  2012;12(2):181-188.
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 multi-determined behavior and associated with a multitude of health consequences. Thus, examining a broader range of candidate genes associated with a boarder 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=1,130 Mexican origin youth) provided a saliva sample and data on PA and sensation seeking tendencies in 2008–09. Participants were genotyped for 630 functional and tagging variants in the dopamine, serotonin, and cannabinoid pathways. Overall 30% of participants (males – 37.6%; females – 22.0%) reported ≥60 minutes of PA on five out of seven 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 ACE (rs8066276 OR=1.44; p=0.012) and 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 SNAP25 (rs363035 OR=0.53; p=0.005) and 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.
PMCID: PMC3581711  PMID: 23190435
Physical Activity; Genes; Sensation Seeking; Mexican origin youth
3.  Maternal current smoking: Concordance between adolescent proxy and mother’s self-report 
Nicotine & Tobacco Research  2009;11(8):1016-1019.
The purpose of this study was to examine the extent to which adolescent reports on mother’s smoking status and mother’s self-reports on smoking are concordant with one another.
Mothers self-reported on their smoking at two timepoints (first query and second query), while the adolescents reported on their mother’s smoking status at one timepoint. Kappa values and percent exact agreement as well as sensitivity and specificity were calculated to examine the degree of agreement between child and mother’s reports at the two timepoints.
Overall, the results indicated good concordance between mothers’ self-reports and adolescent reports on smoking. Specifically, higher concordance was observed for mother’s first query compared with mother’s second query (Κ = 0.69 vs. Κ = 0.51). Younger adolescents and girls provided more concordant reports than older adolescents and boys.
The results indicate that adolescent reports on mothers’ smoking behavior can be used as a proxy to obtain data if mothers’ self-report data are not available. Our results further suggest that when reports are not collected concurrently, self-report data obtained from the mothers prior to the proxy report obtained from her adolescent may be more reliable than the other way around.
PMCID: PMC2711984  PMID: 19531668
4.  Cigarette Experimentation and the Population Attributable Fraction for Associated Genetic and Non-Genetic Risk Factors 
PLoS ONE  2013;8(1):e53868.
We, and others, have shown that experimenting with cigarettes is a function of both non-genetic and genetic factors. In this analysis we ask: how much of the total risk of experimenting with cigarettes, among those who had not experimented with cigarettes when they enrolled in a prospective cohort, is attributable to genetic factors and to non-genetic factors?
Participants (N = 1,118 Mexican origin youth), recruited from a large population-based cohort study in Houston, Texas, provided prospective data on cigarette experimentation over three years. Non-genetic data were elicited twice – baseline and follow-up. Participants were genotyped for 672 functional and tagging variants in the dopamine, serotonin and opioid pathways.
In the overall model, the adjusted combined non-genetic PAF was 71.2% and the adjusted combined genetic PAF was 58.5%. Among committed never smokers the adjusted combined non-genetic PAF was 67.0% and the adjusted combined genetic PAF was 53.5%. However, among cognitively susceptible youth, the adjusted combined non-genetic PAF was 52.0% and the adjusted combined genetic PAF was 68.4%.
Our results suggest there may be differences in genotypes between youth who think they will try cigarettes in the future compared to their peers who think they will not and underscore the possibility that the relative influence of genetic vs. non-genetic factors on the uptake of smoking may vary between these two groups of youth.
A clearer understanding of the relative role of genetic vs. non-genetic factors in the uptake of smoking may have implications for the design of prevention programs.
PMCID: PMC3547034  PMID: 23342024
5.  Cigarette Experimentation in Mexican Origin Youth: Psychosocial and Genetic Determinants 
Established psychosocial risk factors increase the risk for experimentation among Mexican-origin youth. Now we comprehensively investigate the added contribution of select polymorphisms in candidate genetic pathways associated with sensation seeking, risk taking, and smoking phenotypes to predict experimentation.
Participants, (N=1,118 Mexican origin youth) recruited from a large population-based cohort study in Houston, Texas, provided prospective data on cigarette experimentation over three years. Psychosocial data were elicited twice—baseline and final follow-up. Participants were genotyped for 672 functional and tagging variants in the dopamine, serotonin and opioid pathways.
After adjusting for gender and age, with a Bayesian False Discovery Probability set at 0.8 and prior probability of 0.05, six gene variants were significantly associated with risk of experimentation. After controlling for established risk factors, multivariable analyses revealed that participants with six or more risk alleles were 2.25 (95%CI: 1.62–3.13) times more likely to have experimented since baseline compared to participants with five or fewer. Among committed never smokers (N=872), three genes (OPRM1, SNAP25, HTR1B) were associated with experimentation as were all psychosocial factors. Among susceptible youth (N=246) older age at baseline, living with a smoker, and three different genes (HTR2A, DRD2, SLC6A3) predicted experimentation.
Our findings, which have implications for development of culturally-specific interventions, need to be validated in other ethnic groups.
These results suggest that variations in select genes interact with a cognitive predisposition toward smoking. In susceptible adolescents, the impact of the genetic variants appears to be larger compared to committed never smokers.
PMCID: PMC3382046  PMID: 22028400
6.  Psychosocial Risk and Correlates of Early Menarche in Mexican-American Girls 
American Journal of Epidemiology  2011;173(10):1203-1210.
Mexican-American girls have one of the fastest rates of decline in age at menarche. To date, no study has addressed the role of psychosocial factors on age at menarche in this population. Using data from a longitudinal cohort of Mexican-American girls from the Houston, Texas, metropolitan area recruited in 2005, the authors investigated associations between family life and socioeconomic environment and age at menarche in 523 girls. After adjusting for maternal age at menarche, daughter's age, and body mass index at baseline, perception of family life environment as conflict-prone was significantly associated with an earlier age at menarche (< 11 years). Additionally, there was a 2-fold higher risk (odds ratio = 2.22, 95% confidence interval: 1.12, 4.40) of early menarche among daughters of mothers who were single parents compared with those who were not. Furthermore, girls who matured early had a 2.5-fold increased risk (odds ratio = 2.69, 95% confidence interval: 1.04, 6.96) of experimenting with cigarettes compared with those who had an average-to-late age at menarche (≥ 11 years). This study provides important information regarding the role of family life environment and single parenting on age at menarche in Mexican Americans. Awareness of the impact of the family life environment and fathers’ absence during the early years should be emphasized when addressing early age at menarche across cultures.
PMCID: PMC3121322  PMID: 21454827
family cohesion; family conflict; menarche; Mexican Americans; single parenting; smoking; social support
7.  Sensation seeking, risk behaviors and alcohol consumption among Mexican origin youth 
To examine factors associated with ever use of alcohol among Mexican origin youth.
Using a prospective study design, we followed 1053 Mexican origin adolescents. Participants completed two surveys in their homes and three follow-up telephone interviews, every six to eight months, in between. The second home survey was completed 30 months (SD=4.8 months) after baseline. Acculturation, subjective social status, and family cohesion were assessed at baseline and final home visit. Ever drinking, risk behaviors, and sensation seeking tendencies were assessed at the final home visit only.
Overall, 30% of the study participants reported ever drinking alcohol. Multivariate models revealed that being female, increasing age, lower levels of acculturation, family cohesion and subjective social status, higher sensation seeking tendencies and concomitantly engaging in three or four other risk behaviors were associated with ever drinking. Also, social disinhibition, an aspect of sensation seeking, mediated the relationship between engaging in other risk behaviors and alcohol use. This is consistent with previous research, suggesting that social disinhibition is a common factor that underlies the use of alcohol, tobacco, illicit drugs, and other problem behaviors.
The results of this study support taking a family-based approach to prevention that includes discussion of other risk behaviors, especially smoking, among Mexican origin youth. In addition, tailoring programs by gender, directly addressing both how changes in social norms resulting from acculturation can impact a youth’s decision to drink alcohol and underlying gender-based differences in why youth drink could improve the efficacy of preventive interventions.
PMCID: PMC3148938  PMID: 21185526
8.  Cognitive Susceptibility to Smoking: Two Paths to Experimenting among Mexican Origin Youth 
Cognitive susceptibility to smoking, defined as the lack of a firm commitment not to smoke in the future or if offered a cigarette by a friend, begins in childhood and is an early phase in the transition from never to ever smoking. Our objectives were to examine susceptibility to smoking and other psychosocial risk factors for experimentation with cigarettes among Mexican origin adolescents and to determine whether susceptibility status moderates the relationship between established risk factors for experimentation with cigarettes and future experimentation. We examined susceptibility and several psychosocial factors associated with susceptibility as baseline predictors of experimentation after 3 years of follow-up among 964 Mexican origin girls and boys between 11 and 13 years of age from the Houston metropolitan area. Participants were recruited between May 2005 and October 2006 and reported that they had never experimented with cigarettes at baseline. Baseline susceptibility and experimentation rates were 23% and 9%, respectively, whereas the follow-up experimentation rate, among those who had not experimented at baseline, was 22%. Susceptible adolescents at baseline were 2.6 times more likely to have experimented with cigarettes by follow-up. Baseline susceptibility moderated the relationship between experimentation at follow-up and the psychosocial risk factors assessed at baseline. Susceptibility is a valid and strong marker for the transition to experimentation for Mexican origin adolescents. Our results suggest that tailoring primary prevention programs by a youth’s susceptibility status may increase the efficacy of prevention efforts among Mexican origin youth.
PMCID: PMC3183967  PMID: 19959696
Cancer  2010;116(14):3458-3462.
Recent genome-wide association (GWA) studies of lung cancer have shown that the CHRNA5-A3 region on chromosome 15q24-25.1 is strongly associated with an increased risk of lung cancer and nicotine dependence, and thought to be associated with chronic obstructive airways disease as well. However, it has not been established whether the association between genetic variants and lung cancer risk is a direct one or one mediated by nicotine dependence.
In this paper we applied a rigorous statistical approach, mediation analysis, to examine the mediating effect of smoking behavior and self-reported physician-diagnosed emphysema (chronic obstructive pulmonary disease [COPD]) on the relationship between the CHRNA5-A3 region genetic variant rs1051730 and the risk of lung cancer.
Our results showed that rs1051730 is directly associated with lung cancer risk, but that it is also associated with lung cancer risk through its effect on both smoking behavior and COPD. Furthermore, we showed that COPD is a mediating phenotype that explains part of the effect of smoking behavior on lung cancer. Our results also suggested that smoking behavior is a mediator of the relationship between rs1051730 and COPD risk.
Smoking behavior and COPD are mediators of the association between the SNP rs1051730 and the risk of lung cancer. Also, COPD is a mediator of the association between smoking behavior and lung cancer. Finally, smoking behavior also has mediating effects on the association between the SNP and COPD.
PMCID: PMC3073819  PMID: 20564069
Lung Cancer; COPD; Mediation analysis; smoking behavior; genetic variants
10.  The influence of subjective social status on the relationship between positive outcome expectations and experimentation with cigarettes 
In Texas, Mexican American (MA) adolescents, and in particular boys, are at increased risk of experimenting with cigarettes compared to their black or white counterparts. Positive outcome expectations (POE), the functional social significance ascribed to cigarettes, and subjective social status (SSS), the adolescents’ subjective views of where they lie in the school-based social hierarchy, are independent predictors of smoking. The goal of this study was to test the hypothesis that SSS moderates the relationship between POE and experimentation with cigarettes.
Moderating effects of SSS were examined using a between-subjects 2 by 2 ANOVA and unconditional logistic regression analyses. Using a prospective study design, we followed 1,142 MA adolescents aged 11 to 13. Participants completed a baseline survey at home, which assessed POE, SSS, and smoking and were followed via telephone at 6 monthly intervals over a 12 month period to assess changes in smoking behavior.
At follow-up, there were 99 new experimenters. Consistent with our hypothesis, adolescents who reported moderate-low SSS and who held POE at baseline were more likely to have experimented with cigarettes at either follow-up than their peers with moderate-low SSS who held less POE (OR=1.92, CI: 1.02–3.58). There was no association between outcome expectations and experimenting among adolescents with high SSS (OR=1.79, CI: 0.73–4.36). Low SSS boys were more likely to experiment than girls and high SSS boys.
The results of this study indicate that adolescents with moderate-low SSS hold different outcome expectations about smoking than their higher SSS peers. The results underscore the possibility that moderate-low SSS adolescents view behaviors such as smoking as a way to achieve higher SSS and thereby increase their peer social standing. Our results suggest that, in addition to tailoring intervention efforts by gender, placing adolescents of similar social standing to one another within the school into intervention groups that are led by a peer-nominated peer may increase the overall effectiveness of these peer-led prevention efforts.
PMCID: PMC2705959  PMID: 19306792

Results 1-10 (10)