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1.  Factors Associated with High Transmission Risk and Detectable Plasma HIV RNA in HIV-infected MSM on ART 
International journal of STD & AIDS  2014;25(10):734-741.
HIV transmission risk is increased during ART use if individuals are not virologically suppressed and engage in high risk transmission behavior. Baseline data of HIV-infected MSM with recent history of risky behavior on ART for ≥3 months (n=139) was evaluated to assess predictors of detectable viremia and HIV transmission risk taking behavior. 24 subjects had VL>75 c/mL and 12 had VL>1000 c/mL. In multivariable regression analyses, subjects with VL>75 c/mL were more likely to be Black (OR 4.48, p=0.007), have lower CD4 cells (OR 0.727, p=0.005) and have used methamphetamines in the last month (OR 6.64, p=0.019). Subjects with VL>1000 c/mL were more likely to have lower CD4 cells (OR 0.494, p=0.004), report <90% adherence (OR 7.94; p=0.046) and have used methamphetamines in the last month (OR 10.01, p=0.034). Subjects with VL>75c/mL with the greatest transmission risk behavior (n=14) were more likely to be Black (OR 8.00, p=0.006), have lower CD4 cells (OR 0.657, p=0.009) and have used methamphetamines in the last month (OR 5.20, p=0.042). High risk HIV transmission behavior with viremia occurred in 10% of the cohort. Future efforts to reduce HIV transmission among MSM on ART will require combined interventions that target risk-taking behaviors and substance use.
PMCID: PMC4303352  PMID: 24452730
2.  Hair Cortisol, Perceived Stress and Dispositional Optimism: A Pilot Study among Adolescents 
Psychological stress is often associated with poor health-related outcomes. One potential biomarker for chronic stress, hair cortisol, is minimally invasive compared to other cortisol collection techniques. This pilot study examined the relationships between hair cortisol and self-reported perceived stress, stressful life events, depressive symptoms, and dispositional optimism among adolescents.
This cross-sectional study comprised of a convenience sample of 27 adolescents (age: M=14.96, SD=1.63) recruited from a Southern California after-school program. Along with demographic and hair characteristics (e.g., hair color, type, etc.), participants completed the Perceived Stress Scale, Stressful Life Events checklist, CES-D (depressive symptoms), and Life Orientation Test (optimism). Hair cortisol was measured by analyzing hair samples approximately 1 cm from the scalp representing one month of cortisol exposure.
Hair cortisol had a significant inverse association with dispositional optimism (r=−0.44, p<0.05). Hair cortisol was not significantly associated with self-reported perceived stress, stressful life events, or depressive symptoms.
Assessment of hair cortisol may prove beneficial as an objective measure in research examining chronic stress-related outcomes among adolescents. Resiliency or protective dispositions, such as optimism, merit attention in relation to this biomarker.
PMCID: PMC4241294  PMID: 25426491
Hair cortisol; Stress; Stressful life events; Dispositional optimism; Adolescents
Pediatric blood & cancer  2013;60(9):1470-1477.
Parents of childhood cancer survivors (CCS) experience considerable distress related to their child’s cancer. However, little is known about cultural variation in this experience. We examine parental distress, specifically symptoms of posttraumatic stress (PTSS) and depression, comparing Hispanic and non-Hispanic parents of CCS.
79 Hispanic and 60 non-Hispanic parents of CCS (currently aged 14–25, off treatment ≥2 years) completed questionnaires assessing demographics, depression, PTSS, perceived stress, and child’s health status/quality of life (QOL). T-tests and chi-square statistics were used to compare differences in demographic characteristics between Hispanic and non-Hispanic parents and multivariable regression was used to determine independent risk factors associated with parental PTSS and depression.
Hispanic parents were significantly younger, had less education, lower incomes and reported significantly more PTSS and depressive symptoms than non-Hispanic parents (all p-values<0.0001). Among Hispanic parents, foreign birthplace predicted higher PTSS after controlling for other factors (p<0.001). Hispanic parents, regardless of birthplace, reported more depressive symptoms than non-Hispanic parents (US-born, p<0.05; foreign-born, p<0.01). For PTSS and depression, there were positive relationships with parental stress and negative relationships with the child’s psychosocial QOL. Hispanic and non-Hispanic CCS did not differ significantly on disease and treatment factors or health-related QOL.
Hispanic parents of CCS may be at greater risk for poorer mental health outcomes. Ethnic-specific factors (e.g., acculturation, immigration status and previous trauma) may influence parents’ responses and adjustment to their child’s cancer. Research is needed to determine how to meet the needs of the most vulnerable parents.
PMCID: PMC4118593  PMID: 23512267
4.  The association between contextual socioeconomic factors and prevalent asthma in a cohort of southern California school children 
Social science & medicine (1982)  2007;65(8):1792-1806.
Spatial variation in childhood asthma and a recent increase in prevalence indicate that environmental factors play a significant role in the etiology of this important disease. Socioeconomic position (SEP) has been associated inversely and positively with childhood asthma. These contradictory results indicate a need for systematic research about SEP and asthma. Pathways have been suggested for effects of SEP on asthma at both the individual and community level. We examined the relationship of prevalent asthma to community-level indicators of SEP among 5762 children in 12 Southern California, using a multilevel random effects model. Estimates of community-level SEP were derived by summarizing census block group-level data using a novel method of weighting by the proportion of the block groups included in a community-specific bounding rectangle that contained 95% of local study subjects. Community characteristics included measures of male unemployment, household income, low education (i.e. no high school diploma), and poverty. There was a consistent inverse association between male unemployment and asthma across the inter-quartile range of community unemployment rates, indicating that asthma rates increase as community SEP increases. The results were robust to individual-level confounding, methods for summarizing census block group data to the community level, scale of analysis (i.e. community-level vs. neighborhood-level) and the modeling algorithm. The positive association between SEP and prevalent childhood asthma might be explained by differential access to medical care that remains unmeasured, by the hygiene hypothesis (e.g. lower SES may associate with higher protective exposures to endotoxin in early life), or by SEP acting as a proxy for unmeasured neighborhood characteristics.
PMCID: PMC4098912  PMID: 17658674
USA; neighborhood; childhood asthma; multi-level modeling; socioeconomic position; contextual factors
5.  HIV and Recent Illicit Drug Use Interact to Affect Verbal Memory in Women 
HIV infection and illicit drug use are each associated with diminished cognitive performance. This study examined the separate and interactive effects of HIV and recent illicit drug use on verbal memory, processing speed and executive function in the multicenter Women's Interagency HIV Study (WIHS).
Participants included 952 HIV-infected and 443 HIV-uninfected women (mean age=42.8, 64% African-American). Outcome measures included the Hopkins Verbal Learning Test - Revised (HVLT-R) and the Stroop test. Three drug use groups were compared: recent illicit drug users (cocaine or heroin use in past 6 months, n=140), former users (lifetime cocaine or heroin use but not in past 6 months, n=651), and non-users (no lifetime use of cocaine or heroin, n=604).
The typical pattern of recent drug use was daily or weekly smoking of crack cocaine. HIV infection and recent illicit drug use were each associated with worse verbal learning and memory (p's<.05). Importantly, there was an interaction between HIV serostatus and recent illicit drug use such that recent illicit drug use (compared to non-use) negatively impacted verbal learning and memory only in HIV-infected women (p's <0.01). There was no interaction between HIV serostatus and illicit drug use on processing speed or executive function on the Stroop test.
The interaction between HIV serostatus and recent illicit drug use on verbal learning and memory suggests a potential synergistic neurotoxicity that may affect the neural circuitry underlying performance on these tasks.
PMCID: PMC3628722  PMID: 23392462
6.  Trait Mindfulness Helps Shield Decision-making From Translating Into Health-risk Behavior 
The cognitive tendency toward mindfulness may influence the enactment of health and risk behaviors by its bringing increased attention to and awareness of decision-making processes underlying behavior. The present study examined the moderating effect of trait mindfulness on associations between intentions to smoke (ITS)/smoking refusal self-efficacy (SRSE) and smoking frequency.
Self-reports from Chinese adolescents (N=5,287; M age=16.2, SD=0.7; 48.8% female) were collected in 24 schools. Smoking frequency was regressed on latent factor interactions MAAS*ITS and MAAS*SRSE, adjusting for school clustering effects and covariates.
Both interaction terms were significant in cross-sectional analyses and showed high ITS predicted higher smoking frequency among those low relative to high in trait mindfulness while low SRSE predicted higher smoking frequency among those low relative to high in trait mindfulness.
Findings suggest trait mindfulness possibly shields against decision-making processes that place adolescents at risk for smoking.
PMCID: PMC3505281  PMID: 23174469
Mindfulness; cigarette smoking; intentions to smoke; smoking refusal self-efficacy
7.  Testing the indirect effect of trait mindfulness on adolescent cigarette smoking through negative affect and perceived stress mediators 
Journal of substance use  2012;17(5-6):417-429.
Mindfulness refers to an enhanced attention to and awareness of present moment experience. This study examined how trait mindfulness, as measured with six items from Mindfulness Attention Awareness Scale, might influence adolescent cigarette smoking frequency through its impact on depressive affect, anger affect and perceived stress mediators. Self-reported data from Chinese adolescents (N = 5287, mean age = 16.2 years, SD = 0.7; 48.8% females) were collected within 24 schools. The product of coefficients test was used to determine significant mediation paths. Results from baseline cross-sectional data indicated that trait mindfulness had a significant indirect effect on past 30-day smoking frequency through depressive affect, anger affect and perceived stress mediators. Results from 13-month longitudinal data indicated that these indirect effects remained significant for depressive affect and perceived stress but not for anger affect. Findings from this study may suggest that heightening mindfulness among adolescents may indirectly reduce cigarette smoking perhaps by improving affect regulation competencies.
PMCID: PMC3705933  PMID: 23847448
Mindfulness; affect regulation; smoking; mediation; adolescents
8.  Psychometric Assessment of the Mindful Attention Awareness Scale (MAAS) Among Chinese Adolescents 
Assessment  2011;19(1):42-52.
The Mindful Attention Awareness Scale (MAAS) has the longest empirical track record as a valid measure of trait mindfulness. Most of what is understood about trait mindfulness comes from administering the MAAS to relatively homogenous samples of Caucasian adults. This study rigorously evaluates the psychometric properties of the MAAS among Chinese adolescents attending high school in Chengdu, China. Classrooms from 24 schools were randomly selected to participate in the study. Three waves of longitudinal data (N = 5,287 students) were analyzed. MAAS construct, nomological, and incremental validity were evaluated as well as its measurement invariance across gender using latent factor analyses. Participants’ mean age was 16.2 years (SD = 0.7), and 51% were male. The 15-item MAAS had adequate fit to the one-dimensional factor structure at Wave 1, and this factor structure was replicated at Wave 2. A 6-item short scale of the MAAS fit well to the data at Wave 3. The MAAS maintained reliability (Cronbach’s α = .89–.93; test–restest r = .35–.52), convergent/discriminant validity, and explained additional variance in mental health measures beyond other psychosocial constructs. Both the 15- and 6-item MAAS scales displayed at least partial factorial invariance across gender. The findings suggest that the MAAS is a sound measure of trait mindfulness among Chinese adolescents. To reduce respondent burden, the MAAS 6-item short-scale provides an option to measure trait mindfulness.
PMCID: PMC3705937  PMID: 21816857
Mindful Attention Awareness Scale (MAAS); latent factor analysis; construct validity; Chinese; adolescents
9.  Social Network Status and Depression among Adolescents: An Examination of Social Network Influences and Depressive Symptoms in a Chinese Sample 
Research in human development  2011;8(1):67-88.
Despite the well established influence of peer experiences on adolescent attitudes, thoughts, and behaviors, surprisingly little research has examined the importance of peer context and the increased prevalence of depressive symptoms accompanying the transition into adolescence. Examination of social networks may provide some insight into the role of peers in the vulnerability of some adolescents to depression. To address this issue, we leveraged an existing sample of 5,563 Chinese 10th graders to incorporate social network data into a multilevel regression model of depressive symptoms. We found that, in this sample, being nominated as a friend was more important than being nominated as most liked. Social network centrality was significantly associated with depression; those adolescents who were less connected were more likely to suffer from depression. The risk of depression for those who were marginal members of classroom social networks was substantial. These findings suggest that a social network perspective could help to increase the effectiveness of programs aimed at preventing adolescent depression.
PMCID: PMC3515061  PMID: 23226988
Social Network; Adolescent; Depressive Symptoms; Peer relations; China
10.  Parental Stress Increases the Detrimental Effect of Traffic Exposure on Children's Lung Function 
Rationale: Emerging evidence indicates that psychosocial stress enhances the effect of traffic exposure on the development of asthma.
Objectives: We hypothesized that psychosocial stress would also modify the effect of traffic exposure on lung function deficits.
Methods: We studied 1,399 participants in the Southern California Children's Health Study undergoing lung function testing (mean age, 11.2 yr). We used hierarchical mixed models to assess the joint effect of traffic-related air pollution and stress on lung function.
Measurements and Main Results: Psychosocial stress in each child's household was assessed based on parental response to the perceived stress scale (range, 0–16) at study entry. Exposures to nitric oxide, nitrogen dioxide, and total oxides of nitrogen (NOx), surrogates of the traffic-related pollution mixture, were estimated at schools and residences based on a land-use regression model. Among children from high-stress households (parental perceived stress scale >4) deficits in FEV1 of 4.5 (95% confidence interval, −6.5 to −2.4) and of 2.8% (−5.7 to 0.3) were associated with each 21.8 ppb increase in NOx at homes and schools, respectively. These pollutant effects were significantly larger in the high-stress compared with lower-stress households (interaction P value 0.007 and 0.05 for residential and school NOx, respectively). No significant NOx effects were observed in children from low-stress households. A similar pattern of association was observed for FVC. The observed associations for FEV1 and FVC remained after adjusting for sociodemographic factors and after restricting the analysis to children who do not have asthma.
Conclusions: A high-stress home environment is associated with increased susceptibility to lung function effects of air pollution both at home and at school.
PMCID: PMC3208647  PMID: 21700914
parental stress; traffic exposure; lung function; children
11.  Atazanavir Concentration in Hair Is the Strongest Predictor of Outcomes on Antiretroviral Therapy 
In a longitudinal study of outcomes on atazanavir-based therapy in a large cohort of HIV-infected women, hair levels of atazanavir were the strongest independent predictor of virologic suppression. Hair antiretroviral concentrations may serve as a useful tool in HIV care.
Background. Adequate exposure to antiretrovirals is important to maintain durable responses, but methods to assess exposure (eg, querying adherence and single plasma drug level measurements) are limited. Hair concentrations of antiretrovirals can integrate adherence and pharmacokinetics into a single assay.
Methods. Small hair samples were collected from participants in the Women's Interagency HIV Study (WIHS), a large cohort of human immunodeficiency virus (HIV)-infected (and at-risk noninfected) women. From 2003 through 2008, we analyzed atazanavir hair concentrations longitudinally for women reporting receipt of atazanavir-based therapy. Multivariate random effects logistic regression models for repeated measures were used to estimate the association of hair drug levels with the primary outcome of virologic suppression (HIV RNA level, <80 copies/mL).
Results. 424 WIHS participants (51% African-American, 31% Hispanic) contributed 1443 person-visits to the analysis. After adjusting for age, race, treatment experience, pretreatment viral load, CD4 count and AIDS status, and self-reported adherence, hair levels were the strongest predictor of suppression. Categorized hair antiretroviral levels revealed a monotonic relationship to suppression; women with atazanavir levels in the highest quintile had odds ratios (ORs) of 59.8 (95% confidence ratio, 29.0–123.2) for virologic suppression. Hair atazanavir concentrations were even more strongly associated with resuppression of viral loads in subgroups in which there had been previous lapses in adherence (OR, 210.2 [95% CI, 46.0–961.1]), low hair levels (OR, 132.8 [95% CI, 26.5–666.0]), or detectable viremia (OR, 400.7 [95% CI, 52.3–3069.7]).
Conclusions. Antiretroviral hair levels surpassed any other predictor of virologic outcomes to HIV treatment in a large cohort. Low antiretroviral exposure in hair may trigger interventions prior to failure or herald virologic failure in settings where measurement of viral loads is unavailable. Monitoring hair antiretroviral concentrations may be useful for prolonging regimen durability.
PMCID: PMC3079399  PMID: 21507924
12.  Sitting-Meditation Interventions Among Youth: A Review of Treatment Efficacy 
Pediatrics  2009;124(3):e532-e541.
Although the efficacy of meditation interventions has been examined among adult samples, meditation treatment effects among youth are relatively unknown. We systematically reviewed empirical studies for the health-related effects of sitting-meditative practices implemented among youth aged 6 to 18 years in school, clinic, and community settings.
A systematic review of electronic databases (PubMed, Ovid, Web of Science, Cochrane Reviews Database, Google Scholar) was conducted from 1982 to 2008, obtaining a sample of 16 empirical studies related to sitting-meditation interventions among youth.
Meditation modalities included mindfulness meditation, transcendental meditation, mindfulness-based stress reduction, and mindfulness-based cognitive therapy. Study samples primarily consisted of youth with preexisting conditions such as high-normal blood pressure, attention-deficit/hyperactivity disorder, and learning disabilities. Studies that examined physiologic outcomes were composed almost entirely of African American/black participants. Median effect sizes were slightly smaller than those obtained from adult samples and ranged from 0.16 to 0.29 for physiologic outcomes and 0.27 to 0.70 for psychosocial/behavioral outcomes.
Sitting meditation seems to be an effective intervention in the treatment of physiologic, psychosocial, and behavioral conditions among youth. Because of current limitations, carefully constructed research is needed to advance our understanding of sitting meditation and its future use as an effective treatment modality among younger populations.
PMCID: PMC3195513  PMID: 19706568
literature review; meditation; mindfulness; children; adolescents; youth; efficacy
13.  Rodent Allergen in Los Angeles Inner City Homes of Children with Asthma 
Journal of Urban Health   2007;85(1):52-61.
Recent studies have examined the presence of mouse allergen in inner city children with asthma. Researchers have found high levels of rodent allergen in homes sampled in the northeast and midwest United States, but there has been considerable variation between cities, and there have been few studies conducted in western states. We evaluated the frequency of rodent sightings and detectable mouse allergen and the housing conditions associated with these outcomes in inner city homes in Los Angeles. Two hundred and two families of school children, ages 6–16 living in inner city neighborhoods, participated in the study. Families were predominantly Latino (94%), and Spanish speaking (92%). At study entry, parents completed a home assessment questionnaire, and staff conducted a home evaluation and collected kitchen dust, which was analyzed for the presence of mouse allergen. Fifty-one percent of homes had detectable allergen in kitchen dust. All 33 families who reported the presence of rodents had detectable allergen in the home and were also more likely to have increased levels of allergen compared to those who did not report rodents. Unwashed dishes or food crumbs, lack of a working vacuum, and a caretaker report of a smoker in the home were all significantly associated with a greater risk of rodent sightings or detectable allergen (P < 0.05). Detached homes were significantly more likely to have detectable allergen. The prevalence of allergen is common enough that it may have public health implications for asthmatic children, and detectable allergen was not routinely identified based on rodent sightings. Many of the predictors of rodent allergen are amenable to low-cost interventions that can be integrated with other measures to reduce exposure to indoor allergens.
PMCID: PMC2430140  PMID: 18004665
Asthma; Mouse allergen; House dust; Rodent; Environment
14.  Correlates of Unprotected Sex Among Adult Heterosexual Men Living with HIV 
The correlates of unprotected sex among a sample of heterosexual men living with HIV (n = 121) were examined to determine whether patient characteristics can be used as a basis for tailoring safer sex counseling in the clinic setting. Potential correlates of self-reported unprotected oral sex (fellatio) and vaginal sex included participant demographics (e.g., age, ethnicity), disease status (CD4 counts, viral load, years since diagnosis), safer sex beliefs (e.g., condom attitudes), substance use, psychological characteristics (depressive symptoms, dispositional optimism and pessimism), and sex partner characteristics (main/casual partner, HIV status of partner, and duration of relationship). A series of logistic regression analyses were used to determine significant relationships. Correlates of reported levels of prior 3-month unprotected fellatio (24%) and vaginal (21%) sex were not associated with the type of relationship (main or casual) or perceived HIV serostatus of the partner (positive, negative, or unknown). Unprotected fellatio was positively associated with age and CD4 count and inversely associated with optimism and positive condom attitudes (all p's < 0.05). Unprotected vaginal sex was positively associated with duration of relationship and inversely associated with positive condom attitudes. Prevention efforts among sexually active adult heterosexual men living with HIV may benefit from focusing on improving attitudes towards condom use regardless of partner relationship status.
PMCID: PMC2430484  PMID: 16736114
Condom attitudes; Heterosexual; HIV; Optimism; Unsafe sex
15.  Competing definitions of contextual environments 
The growing interest in the effects of contextual environments on health outcomes has focused attention on the strengths and weaknesses of alternate contextual unit definitions for use in multilevel analysis. The present research examined three methods to define contextual units for a sample of children already enrolled in a respiratory health study. The Inclusive Equal Weights Method (M1) and Inclusive Sample Weighted Method (M2) defined communities using the boundaries of the census blocks that incorporated the residences of the CHS participants, except that the former estimated socio-demographic variables by averaging the census block data within each community, while the latter used weighted proportion of CHS participants per block. The Minimum Bounding Rectangle Method (M3) generated minimum bounding rectangles that included 95% of the CHS participants and produced estimates of census variables using the weighted proportion of each block within these rectangles. GIS was used to map the locations of study participants, define the boundaries of the communities where study participants reside, and compute estimates of socio-demographic variables. The sensitivity of census variable estimates to the choice of community boundaries and weights was assessed using standard tests of significance.
The estimates of contextual variables vary significantly depending on the choice of neighborhood boundaries and weights. The choice of boundaries therefore shapes the community profile and the relationships between its components (variables).
Multilevel analysis concerned with the effects of contextual environments on health requires careful consideration of what constitutes a contextual unit for a given study sample, because the alternate definitions may have differential impact on the results. The three alternative methods used in this research all carry some subjectivity, which is embedded in the decision as to what constitutes the boundaries of the communities. The Minimum Bounding Rectangle was preferred because it focused attention on the most frequently used spaces and it controlled potential aggregation problems. There is a need to further examine the validity of different methods proposed here. Given that no method is likely to capture the full complexity of human-environment interactions, we would need baseline data describing people's daily activity patterns along with expert knowledge of the area to evaluate our neighborhood units.
PMCID: PMC1702345  PMID: 17156433

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