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2.  Psychometric Properties of Reverse-Scored Items on the CES-D in a Sample of Ethnically Diverse Older Adults 
Psychological assessment  2011;23(2):558-562.
Reverse-scored items on assessment scales increase cognitive processing demands, and may therefore lead to measurement problems for older adult respondents.
To examine possible psychometric inadequacies of reverse-scored items on the Center for Epidemiologic Studies Depression Scale (CES-D) when used to assess ethnically diverse older adults.
Using baseline data from a gerontologic clinical trial (n=460), we tested the hypotheses that the reversed items on the CES-D: (a) are less reliable than non-reversed items, (b) disproportionately lead to intra-individually atypical responses that are psychometrically problematic, and (c) evidence improved measurement properties when an imputation procedure based on the scale mean is used to replace atypical responses.
In general, the results supported the hypotheses. Relative to non-reversed CES-D items, the four reversed items were less internally consistent, were associated with lower item-scale correlations, and were more often answered atypically at an intra-individual level. Further, the atypical responses were negatively correlated with responses to psychometrically sound non-reversed items that had similar content. The use of imputation to replace atypical responses enhanced the predictive validity of the set of reverse-scored items.
Among older adult respondents reverse-scored items are associated with measurement difficulties. It is recommended that appropriate correction procedures such as item re-administration or statistical imputation be applied to reduce the difficulties.
PMCID: PMC3115428  PMID: 21319906
CES-D; depression; reversed item format; older adults
3.  Temporal Relationship Between Insulin Sensitivity and the Pubertal Decline in Physical Activity in Peripubertal Hispanic and African American Females 
Diabetes Care  2013;36(11):3739-3745.
Little attention has been paid to possible intrinsic biological mechanisms for the decline in physical activity that occurs during puberty. This longitudinal observational study examined the association between baseline insulin sensitivity (SI) and declines in physical activity and increases in sedentary behavior in peripubertal minority females over a year.
Participants were Hispanic and African American girls (n = 55; 76% Hispanic; mean age 9.4 years; 36% obese). SI and other insulin indices were measured at baseline using the frequently sampled intravenous glucose tolerance test. Physical activity was measured on a quarterly basis by accelerometry and self-report.
Physical activity declined by 25% and time spent in sedentary behaviors increased by ∼13% over 1 year. Lower baseline SI predicted the decline in physical activity measured by accelerometry, whereas higher baseline acute insulin response to glucose predicted the decline in physical activity measured by self-report. Time spent in sedentary behavior increased by ~13% over 1 year, and this was predicted by lower baseline SI. All models controlled for adiposity, age, pubertal stage, and ethnicity.
When evaluated using a longitudinal design with strong outcome measures, this study suggests that lower baseline SI predicts a greater decline in physical activity in peripubertal minority females.
PMCID: PMC3816891  PMID: 23846812
4.  Acculturation and Substance Use: Social Influence as a Mediator among Hispanic Alternative High School Youth* 
Research suggests that acculturation increases the risk of substance use among Hispanic youth. However, this process is not well understood. This study examined associations between acculturation and several substance use indicators among a sample of 714 Hispanic youth attending alternative high schools in southern California. Peer social influence was assessed as a potential mediator Acculturation, measured by language use, was associated with increased risk of lifetime alcohol, marijuana, and current alcohol, cigarettes, marijuana, and hard drug use, controlling for age, socioeconomic status, and gender Results of mediation analyses indicate that peer social influence mediated the relationship between acculturation and lifetime alcohol, and current alcohol, cigarettes, and hard drug use. Evidence for partial mediation was observed with lifetime and current marijuana use. These results provide evidence that peer social influence is an important mediating variable that should be considered when examining the relationship between acculturation and substance use.
PMCID: PMC4181567  PMID: 19537458
5.  Bullying Victimization as a Mediator of Associations between Cultural/familial Variables, Substance use and Depressive symptoms among Hispanic Youth 
Ethnicity & health  2013;18(4):415-432.
This article examines the antecedents and consequences of bullying victimization among a sample of Hispanic high school students. Although cultural and familial variables have been examined as potential risk or protective factors for substance use and depression, previous studies have not examined the role of peer victimization in these processes. We evaluated a conceptual model in which cultural and familial factors influenced the risk of victimization, which in turn influenced the risk of substance use and depression.
Data were collected as part of a longitudinal survey study of 9th and 10th grade Hispanic/Latino students in Southern California (n=1167). The student bodies were at least 70% Hispanic/Latino with a range of socioeconomic characteristics represented. We used linear and logistic regression models to test hypothesized relationships between cultural and familial factors and depression and substance and a meditational model to assess whether bullying victimization mediated these associations.
Acculturative stress and family cohesion were significantly associated with bullying victimization. Family cohesion was associated with depression and substance use. Social support was associated with alcohol use. Acculturative stress was associated with higher depression. The associations between acculturative stress and depression, family cohesion and depression, and family cohesion and cigarette use were mediated by bullying victimization.
These findings provide valuable information to the growing, but still limited, literature about the cultural barriers and strengths that are intrinsic to the transition from adolescence to emerging adulthood among Hispanic youth. Our findings are consistent with a mediational model in which cultural/familial factors influence the risk of peer victimization, which in turn influences depressive symptoms and smoking, suggesting the potential positive benefits of school based programs that facilitate the development of coping skills for students experiencing cultural and familial stressors.
PMCID: PMC3723765  PMID: 23297708
Hispanic; acculturation; family cohesion; bullying victimization; depression; substance use
6.  Changes in Friends’ and Parental Influences on Cigarette Smoking from Early through Late Adolescence 
This study examined the changes in friends’ and parental influences on cigarette smoking across two developmentally distinct social environments for adolescents: junior high school and high school.
Longitudinal data consisting of seven repeated measures following 1,001 adolescents from 7th to 12th grade was obtained from the Midwestern Prevention Project. A two-piece Growth Curve Model (GCM) was used to assess the growth trajectory of current cigarette use: one piece for the junior high school period, and the other for the high school period. Perceived friends’ and parental cigarette use were each used as a time-varying covariate in separate GCMs.
Effects of friends’ and parental cigarette use remained significant on adolescent cigarette smoking across the two developmental periods. The magnitude of friends’ effect was in general higher during junior high school than high school. The magnitude of the parental effect remained relatively stable between the two periods. However, decreasing trends in both effects were observed from 10th to 12th grade. Gender differences also emerged. Friends’ and parental effects were greater for girls in their early high school years, whereas friends’ effect decreased in magnitude among girls and increased among boys during high school.
The transition from junior high school to high school represents an opportunity for interventions to counteract peer influence since such influence appeared to be much weaker during this period. However, interventions should continue to target parents as their behavior remains influential through the end of high school.
PMCID: PMC3691293  PMID: 23583505
Adolescence; Smoking; Developmental stages; Peer influences; Parental influences; Longitudinal studies; Growth curve models
7.  Psychometrics of the Eating in Emotional Situations Questionnaire (EESQ) among low-income Latino elementary-school children 
Eating behaviors  2011;12(2):156-159.
The current study examines the psychometric properties of the Eating in Emotional Situations Questionnaire (EESQ) and the frequency of eating in emotional situations among 159 low-income Latino fourth graders. The EESQ assesses eating in emotional situations that are emotion-driven (“I eat when I am lonely”) and context-driven (“I eat when I get a really bad grade”). Internal consistencies for the EESQ subscales and total scale ranged from .70 to .86. Criterion validity of the EESQ was established by statistically significant correlations between the EESQ subscales and total scale, and uncontrollable eating, external eating, and junk food intake. Eating in emotional situations was common in the sample; almost one-half reported eating in at least 3 of the 11 types of emotional situations (e.g. when stressed, sad, bored) and 28% reported eating in at least 6 types. Overall, these findings provide support for the internal consistency and validity of the EESQ in low-income Latino children, and suggest that eating in emotional situations is moderately present in this demographic. Future studies are needed to validate the EESQ in other ethnic groups and examine the longitudinal tracking of eating in emotional situations among Latino youth.
PMCID: PMC3947794  PMID: 21385647
Eating in Emotional Situations Questionnaire (EESQ); emotional eating; children; Latino; Hispanic
8.  Leptin predicts a decline in moderate to vigorous physical activity in minority female children at risk for obesity 
Pediatric obesity  2012;8(1):70-77.
Leptin may influence moderate to vigorous physical activity (MVPA) at the start of puberty. The direction and magnitude of this association is unclear.
To determine the effect of baseline leptin on MVPA over one year in minority girls at high-risk for obesity.
Data came from TRANSITIONS, a longitudinal observational study on the age-related MVPA decline. Fifty peri-pubertal girls aged 8–11 years at baseline participated. Baseline leptin (ng/mL) was collected via a duplicated assay using a double antibody Radio Immune Assay. MVPA (min/day) was measured using accelerometers for at least four 10-hr days on a quarterly basis for up to one year.
Continuous leptin was negatively related to MVPA (p=0.001) independent of central adiposity at baseline and predicted the MVPA decline over one year (p=0.002). For descriptive purposes, baseline leptin was dichotomized at the sample median into ‘high leptin’ and ‘low leptin’ categories to determine whether MVPA trajectories differed between these groups. Girls with ‘low leptin’ at baseline had significantly higher levels of MPVA at baseline, visit 1, and visit 2 compared to girls with ‘high leptin’.
High leptin levels predicted nearly a 12.6% decline in MVPA over one year. These findings provide support for the biological basis of declining MVPA as girls enter puberty.
PMCID: PMC3527645  PMID: 22991241
leptin; accelerometer; biological basis; physical activity; adolescent
9.  The Role of Cognitive Attributions for Smoking in Subsequent Smoking Progression and Regression among Adolescents in China 
Addictive behaviors  2012;38(1):1493-1498.
Previous studies have documented that cognitive attributions are correlated with adolescent smoking. The present study further explored whether cognitive attributions for smoking influenced adolescents’ future smoking behaviors, especially transitions to more advanced stages of smoking.
Participants were 12,382 middle and high school students (48.5% males and 51.5% females) in seven large cities in China. They completed two waves of surveys one year apart. Cognitive attributions for smoking and three smoking behavior outcomes (lifetime smoking, past 30-day smoking, and daily smoking) were assessed. Changes in smoking, including progression from lower stages to higher stages and regression from higher stages to lower stages, over a one-year period, were defined longitudinally. Polychotomous logistic regression was used to examine associations between cognitive attributions for smoking and changes in smoking status over one year, adjusting for demographic characteristics and other plausible confounders.
Seven out of eight cognitive attributions for smoking were associated with subsequent smoking behaviors (p<0.05). Curiosity, autonomy, social image, social belonging, and coping influenced earlier stages of smoking, whereas mental enhancement and engagement influenced later stages of smoking. Curiosity, autonomy, social image, and mental enhancement preceded smoking progression; social belonging prevented smoking regression; and coping and engagement both preceded smoking progression and prevented smoking regression.
This study demonstrates that different cognitive attributions influence smoking at different stages in different ways. These findings could inform smoking prevention and cessation programs targeting Chinese adolescents.
PMCID: PMC3493682  PMID: 23017586
Attributions; Smoking; Attribution Theory; Adolescents; China
10.  Joint Physical Activity and Sedentary Behavior in Parent-Child Pairs 
Research examined joint physical activity and sedentary behavior among 291 parent-child pairs who both wore an accelerometer and global positioning systems (GPS) device over the same 7-day period.
Children were 52.2% female, 8-14 years, and 43.0% Hispanic. Parents were 87.6% female. An Actigraph GT2M accelerometer and GlobalSat BT-335 GPS device collected activity and global positioning data, respectively. Linear distance between the parent and child for each 30-sec. epoch was calculated using geographic coordinates from the GPS. Joint behavior was defined as a separation distance less than 50m between parents and children.
On average during non-school waking hours, parents and children spent 2.4 min. (SD = 4.1) per day performing moderate-to-vigorous physical activity (MVPA) together and 92.9 min. (SD = 40.1) per day in sedentary behavior together. Children engaged in an average of 10 min. per day of MVPA during non-school waking hours when their parent was nearby but not engaging in MVPA. During this same period, parents engaged in 4.6 min. per day of MVPA when their child was nearby but not engaging in MVPA. Household income level and the child’s age were negatively associated with joint MVPA. Girls engaged in a greater percentage of their total MVPA together with their parent than boys. Girls and older children engaged in more sedentary behavior together with their parent than boys and younger children. Older parents engaged in a greater percentage of their sedentary behavior together with their children than younger parents.
Replacing the time that parents and children spend together in sedentary pursuits with joint physical activity could have health benefits, especially for girls, older children, older parents, and higher income families.
PMCID: PMC3399090  PMID: 22367744
moderate-to-vigorous physical activity; accelerometer; global positioning systems; age; sex
11.  Depressive Symptom Deterioration among Predominantly Hispanic Diabetes Patients in Safety Net Care 
Psychosomatics  2012;53(4):347-355.
This study examines clinical predictors of symptom deterioration (relapse/recurrence) at the completion of a clinical intervention trial of depressed, low-income, predominantly Hispanic diabetes patients who were randomized to socio-culturally adapted collaborative depression treatment or usual care and no longer met clinically significant depression criteria at 12 months post-trial baseline.
A sub-cohort of 193 diabetes patients with major depression symptoms at baseline, that were randomized to a 12-month collaborative care intervention (INT) (Problem Solving Therapy and/or pharmacotherapy, telephone symptom monitoring/relapse prevention, behavioral activation and patient navigation support) or enhanced usual care (EUC), and who did not meet major depression criteria at 12 months were subsequently observed over 18 to 24 months.
Post-trial depression symptom deterioration was similar between INT (35.2%) and EUC (35.3%) groups. Among the combined groups, significant predictors of symptom deterioration were baseline history of previous depression and/or dysthymia (odds ratio [OR] =2.66), 12-month PHQ-9 score (OR=1.22), antidepressant treatment receipt during the initial 12-months (OR=2.38), 12-month diabetes symptoms (OR=2.27) and new ICD-9 medical diagnoses in the initial 12 months (OR=1.11) (R2=27%; Max-rescaled R2=37%; Likelihood ratio test, chi-sq=59.79, df=5, p<.0001).
Among predominantly Hispanic diabetes patients in community safety net primary care clinics whose depression had improved over 1 year, more than one third experienced symptom deterioration over the following year. A primary care management depression care protocol that includes ongoing depression symptom monitoring, antidepressant adherence, and diabetes and co-morbid illness monitoring plus depression medication adjustment and behavioral activation may reduce and/or effectively treat depression symptom deterioration.
PMCID: PMC3389136  PMID: 22458987
Depression Recurrence and Relapse; Depression Care Disparities; Depression Symptom Monitoring; Depression and Diabetes; Depression in Hispanics
12.  One Year Post Collaborative Depression Care Trial Outcomes among Predominantly Hispanic Diabetes Safety Net Patients 
General hospital psychiatry  2011;33(5):436-442.
To determine sustained effectiveness in reducing depression symptoms and improving depression care one year following intervention completion.
Of 387 low-income, predominantly Hispanic diabetes patients with major depression symptoms randomized to 12-month socio-culturally adapted collaborative care (psychotherapy and/or antidepressants, telephone symptom monitoring/relapse prevention) or enhanced usual care, 264 patients completed two-year follow-up. Depression symptoms (SCL-20, PHQ-9), treatment receipt, diabetes symptoms, and quality of life were assessed 24 months post-enrollment using intent-to-treat analyses.
At 24 months, more intervention patients received ongoing antidepressant treatment (38% v 25%, chi-square=5.11, df=1, P=0.02); sustained depression symptom improvement (SCL-20<0.5 (adjusted OR=2.06, 95%CI=1.09–3.90, P=0.03), SCL-20 score (adjusted mean difference −0.22, P=0.001), and PHQ-9 ≥50% reduction (adjusted OR=1.87, 95%CI=1.05–3.32, P=0.03). Over 2 years, improved effects were found in significant study group by time interaction for SF-12 mental health, SDS functional impairment, diabetes symptoms, anxiety, and socioeconomic stressors (P=0.02 for SDS, P<0.0001 for all others); however, group differences narrowed over time and were no longer significant at 24 months.
Socio-culturally tailored collaborative care that included maintenance antidepressant medication, ongoing symptom monitoring and behavioral activation relapse prevention was associated with depression improvement over 24 months for predominantly Hispanic patients in primary safety net care.
PMCID: PMC3175272  PMID: 21774987
Depression; Diabetes; Collaborative Care; Safety Net; Hispanic
13.  The influence of the perceived consequences of refusing to share injection equipment among injection drug users: Balancing competing risks 
Addictive behaviors  2011;36(8):835-842.
Injection drug users (IDUs) are at risk for HIV and other bloodborne pathogens through receptive syringe sharing (RSS) and receptive paraphernalia sharing (RPS). Research into the influence of the perceived risk of HIV infection on injection risk behavior has yielded mixed findings. One explanation may be that consequences other than HIV infection are considered when IDUs are faced with decisions about whether or not to share equipment. We investigated the perceived consequences of refusing to share injection equipment among 187 IDUs recruited from a large syringe exchange program in Los Angeles, California, assessed their influence on RSS and RPS, and evaluated gender differences. Two sub-scales of perceived consequences were identified: structural/external consequences and social/internal consequences. In multiple linear regression, the perceived social/internal consequences of refusing to share were associated with both RSS and RPS, after controlling for other psychosocial constructs and demographic variables. Few statistically significant gender differences emerged. Assessing the consequences of refusing to share injection equipment may help explain persistent injection risk behavior, and may provide promising targets for comprehensive intervention efforts designed to address both individual and structural risk factors.
PMCID: PMC3098341  PMID: 21498004
Injection drug use; HIV; gender; perceived consequences; syringe sharing
14.  Association of the Calcyon Neuron-Specific Vesicular Protein Gene (CALY) With Adolescent Smoking Initiation in China and California 
American Journal of Epidemiology  2011;173(9):1039-1048.
Although previous investigations have indicated a role for genetic factors in smoking initiation, the underlying genetic mechanisms are still unknown. In 2,339 adolescents from a Chinese Han population in the Wuhan Smoking Prevention Trial (Wuhan, China, 1998–1999), the authors explored the association of 57 genes in the dopamine pathway with smoking initiation. Using a conservative approach for declaring significance, positive findings were further examined in an independent sample of 603 Caucasian adolescents followed for up to 10 years as part of the Children's Health Study (Southern California, 1993–2009). The authors identified 1 single nucleotide polymorphism (rs2298122) in the calcyon neuron-specific vesicular protein gene (CALY) that was positively associated with smoking initiation in females (odds ratio = 2.21, 95% confidence interval: 1.49, 3.27; P = 8.4 × 10−5) in the Wuhan Smoking Prevention Trial cohort, and they replicated the association in females from the Children's Health Study cohort (hazard rate ratio = 2.05, 95% confidence interval: 1.27, 3.31; P = 0.003). These results suggest that the CALY gene may influence smoking initiation in adolescents, although the potential roles of underlying psychological characteristics that may be components of the smoking-initiation phenotype, such as impulsivity or novelty-seeking, remain to be explored.
PMCID: PMC3121219  PMID: 21415033
adolescent; dopamine; genetic association studies; smoking
15.  Randomized Controlled Trial to Improve Adiposity, Inflammation, and Insulin Resistance in Obese African-American and Latino Youth 
Obesity (Silver Spring, Md.)  2011;20(4):811-818.
The purpose of this study was to examine ethnic differences in the metabolic responses to a 16-week intervention designed to improve insulin sensitivity (SI), adiposity, and inflammation in obese African-American and Latino adolescents. A total of 100 participants (African Americans: n = 48, Latino: n = 52; age: 15.4 ± 1.1 years, BMI percentile: 97.3 ± 3.3) were randomly assigned to interventions: control (C; n = 30), nutrition (N; n = 39, 1×/week focused on decreasing sugar and increasing fiber intake), or nutrition + strength training (N+ST; n = 31, 2×/week). The following were measured at pre- and postintervention: strength, dietary intake, body composition (dual-energy X-ray absorptiometry/magnetic resonance imaging) and glucose/insulin indexes (oral glucose tolerance test (OGTT)/intravenous glucose tolerance test (IVGTT)) and inflammatory markers. Overall, N compared to C and N+ST reported significant improvements in SI (+16.5% vs. −32.3% vs. −6.9% respectively, P < 0.01) and disposition index (DI: +15.5% vs. −14.2% vs. −13.7% respectively, P < 0.01). N+ST compared to C and N reported significant reductions in hepatic fat fraction (HFF: −27.3% vs. −4.3% vs. 0% respectively, P < 0.01). Compared to N, N+ST reported reductions in plasminogen activator inhibitor-1 (PAI-1) (−38.3% vs. +1.0%, P < 0.01) and resistin (−18.7% vs. +11.3%, P = 0.02). There were no intervention effects for all other measures of adiposity or inflammation. Significant intervention by ethnicity interactions were found for African Americans in the N group who reported increases in total fat mass, 2-h glucose and glucose incremental areas under the curve (IAUC) compared to Latinos (P’s < 0.05). These interventions yielded differential effects with N reporting favorable improvements in SI and DI and N+ST reporting marked reductions in HFF and inflammation. Both ethnic groups had significant improvements in metabolic health; however some improvements were not seen in African Americans.
PMCID: PMC3106142  PMID: 21293446
16.  Longitudinal Analysis of Weight Perception and Psychological Factors in Chinese Adolescents 
To investigate associations of overweight status and perception with trajectories of psychological distress in adolescents.
Longitudinal data for 6,970 Chinese adolescents were included. The multivariate Curve-of-Factor Latent Growth Curve Models were adopted to examine trajectories of psychological distress symptoms and associations with overweight status and perception.
After controlling for actual overweight status, psychological distress symptoms were weakly but significantly associated with overweight perception (γ=0.08 for boys and γ=0.10 for girls, P<0.05) and misperception (γ=0.06 for boys and γ=0.09 for girls, P<0.05).
Our findings help understanding associations of overweight perception and psychological well being of adolescents.
PMCID: PMC2957668  PMID: 20950162
weight perception; Chinese adolescents; psychological distress
17.  Testosterone Threshold Levels and Lean Tissue Mass Targets Needed to Enhance Skeletal Muscle Strength and Function: The HORMA Trial 
In the HORMA (Hormonal Regulators of Muscle and Metabolism in Aging) Trial, supplemental testosterone and recombinant human growth hormone (rhGH) enhanced lean body mass, appendicular skeletal muscle mass, muscle performance, and physical function, but there was substantial interindividual variability in outcomes.
One hundred and twelve men aged 65–90 years received testosterone gel (5 g/d vs 10 g/d via Leydig cell clamp) and rhGH (0 vs 3 vs 5 μg/kg/d) in a double-masked 2 × 3 factorial design for 16 weeks. Outcomes included lean tissue mass by dual energy x-ray absorptiometry, one-repetition maximum strength, Margaria stair power, and activity questionnaires. We used pathway analysis to determine the relationship between changes in hormone levels, muscle mass, strength, and function.
Increases in total testosterone of 1046 ng/dL (95% confidence interval = 1040–1051) and 898 ng/dL (95% confidence interval = 892–904) were necessary to achieve median increases in lean body mass of 1.5 kg and appendicular skeletal muscle mass of 0.8 kg, respectively, which were required to significantly enhance one-repetition maximum strength (≥30%). Co-treatment with rhGH lowered the testosterone levels (quantified using liquid chromatography–tandem mass spectrometry) necessary to reach these lean mass thresholds. Changes in one-repetition maximum strength were associated with increases in stair climbing power (r = .26, p = .01). Pathway analysis supported the model that changes in testosterone and insulin-like growth factor 1 levels are related to changes in lean body mass needed to enhance muscle performance and physical function. Testosterone’s effects on physical activity were mediated through a different pathway because testosterone directly affected Physical Activity Score of the Elderly.
To enhance muscle strength and physical function, threshold improvements in lean body mass and appendicular skeletal muscle mass are necessary and these can be achieved by targeting changes in testosterone levels. rhGH augments the effects of testosterone. To maximize functional improvements, the doses of anabolic hormones should be titrated to achieve target blood levels.
PMCID: PMC3032430  PMID: 21059836
Testosterone; Growth hormone; Lean body mass; Muscle performance; Physical function
18.  Physical Activity in US Youth: Impact of Race/Ethnicity, Age, Gender, & Weight Status 
To describe physical activity (PA) levels by race/ethnicity, age, gender, and weight status in a representative sample of U.S. youth.
Cross-sectional data from the 2003–4 and 2005–6 National Health and Nutrition Examination Survey (NHANES) were combined and analyzed. Youth ages 6 to 19 with at least 4 10-hour days of PA measured by accelerometry were included (N=3,106). Outcomes included mean counts per minute and minutes spent in moderate to vigorous PA (MVPA).
6 to 11 year olds spent more time (88 min/day) in MVPA than 12 to 15 (33 min/day) and 16–19 (26 min/day) year olds (p<.001 for both). Females spent fewer min/day in MVPA than males (p<.001). Overall, obese youth spent 16 fewer min/day in MVPA than normal weight youth. However, non-Hispanic White (NHW) males spent 3–4 fewer min/day in vigorous PA than Mexican American (MA) (p=.004) and non-Hispanic Black (NHB) (p<.001) males but had lower obesity rates; and obese 12 to 15 year old MA recorded similar minutes in MVPA per day as normal weight MA (p>.050). There was a significant 3-way age-BMI-race/ethnicity interaction for mean min/day in MVPA (p<.001). Adjustment for total energy intake did not qualitatively alter these results.
Females and older youth were the least active groups. Obese youth were generally less active, but this did not hold uniformly across race/ethnic groups. Cultural or biological factors could moderate the association between PA and obesity in youth.
PMCID: PMC3242154  PMID: 21084930
NHANES; Moderate To Vigorous; Accelerometer; BMI; Adolescent
19.  Initial Status in Growth Curve Modeling for Randomized Trials 
Journal of drug issues  2010;40(1):155-172.
The growth curve modeling (GCM) technique has been widely adopted in longitudinal studies to investigate progression over time. The simplest growth profile involves two growth factors, initial status (intercept) and growth trajectory (slope). Conventionally, all repeated measures of outcome are included as components of the growth profile, and the first measure is used to reflect the initial status. Selection of the initial status, however, can greatly influence study findings, especially for randomized trials. In this article, we propose an alternative GCM approach involving only post-intervention measures in the growth profile and treating the first wave after intervention as the initial status. We discuss and empirically illustrate how choices of initial status may influence study conclusions in addressing research questions in randomized trials using two longitudinal studies. Data from two randomized trials are used to illustrate that the alternative GCM approach proposed in this article offers better model fitting and more meaningful results.
PMCID: PMC3090624  PMID: 21572585
20.  High Calorie, Low Nutrient Food/Beverage Intake and Video Gaming in Children as Potential Signals for Addictive Behavior 
Little is known about the co-occurrence of health risk behaviors in childhood that may signal later addictive behavior. Using a survey, this study evaluated high calorie, low nutrient HCLN intake and video gaming behaviors in 964 fourth grade children over 18 months, with stress, sensation-seeking, inhibitory control, grades, perceived safety of environment, and demographic variables as predictors. SEM and growth curve analyses supported a co-occurrence model with some support for addiction specificity. Male gender, free/reduced lunch, low perceived safety and low inhibitory control independently predicted both gaming and HCLN intake. Ethnicity and low stress predicted HCLN. The findings raise questions about whether living in some impoverished neighborhoods may contribute to social isolation characterized by staying indoors, and HCLN intake and video gaming as compensatory behaviors. Future prevention programs could include skills training for inhibitory control, combined with changes in the built environment that increase safety, e.g., implementing Safe Routes to School Programs.
PMCID: PMC3290975  PMID: 22408581
eating; video gaming; children; addictive behavior
22.  The perceived consequences of safer injection: An exploration of qualitative findings and gender differences 
Psychology, health & medicine  2010;15(5):560-573.
Injection drug users (IDUs) are at risk for HIV and other bloodborne pathogens via syringe and paraphernalia sharing, and women are at elevated risk. Consequences of injection risk behavior such as the risk of becoming infected with HIV have been relatively well studied, though less is known about the consequences of refusing to share injection equipment. We conducted in-depth qualitative interviews with 26 IDUs recruited from a syringe exchange program in Los Angeles, California, USA to understand the consequences that IDUs associate with refusing to share injection equipment and to determine whether these perceived consequences differ by gender. Perceived consequences were organized into four domains using a Social Ecological framework: microsystem (perceived risk of HIV, drug withdrawal or forgoing drug use), exosystem (trust and social norms), mesosystem (precarious housing and shelter policies), and macrosystem (syringe access/inconvenience, economic and legal consequences). Gender differences were identified in some, but not all areas. Effective public health interventions among IDUs will benefit from a holistic perspective that considers the environmental and social rationality (Kowalewski et al., 1997) of decisions regarding injection risk behavior, and assists individuals in addressing the consequences that they perceive to be most salient.
PMCID: PMC2939721  PMID: 20835966
HIV; injection drug use; gender; qualitative methods; perceived consequences; behavioral theory
23.  Overweight, Body Image, and Depression in Asian and Hispanic Adolescents 
To prospectively investigate associations between overweight and depressive symptoms in Asian and Hispanic adolescents.
Data included 780 Hispanic and 375 Asian students. Structural equation model was used to prospectively explore moderation effects of gender, ethnicity, and acculturation on associations of overweight, body image dissatisfaction, and depressive symptoms.
Significant mediation effect was found only in Asian girls (mediation effect=0.16, P<0.05) and girls with high acculturation (mediation effect=0.17, P<0.05). Overweight significantly predicted higher body image dissatisfaction, which in turn was significantly related to depressive symptoms.
Our findings help understanding the association of overweight and experience of depressive symptoms.
PMCID: PMC2860429  PMID: 20218759
overweight; depressive symptoms; body image; acculturation
24.  Effectiveness of a lifestyle intervention in promoting the well-being of independently living older people: results of the Well Elderly 2 Randomised Controlled Trial 
Older people are at risk for health decline and loss of independence. Lifestyle interventions offer potential for reducing such negative outcomes. The aim of this study was to determine the effectiveness and cost-effectiveness of a preventive lifestyle-based occupational therapy intervention, administered in a variety of community-based sites, in improving mental and physical well-being and cognitive functioning in ethnically diverse older people.
A randomised controlled trial was conducted comparing an occupational therapy intervention and a no-treatment control condition over a 6-month experimental phase. Participants included 460 men and women aged 60–95 years (mean age 74.9±7.7 years; 53% <$12 000 annual income) recruited from 21 sites in the greater Los Angeles metropolitan area.
Intervention participants, relative to untreated controls, showed more favourable change scores on indices of bodily pain, vitality, social functioning, mental health, composite mental functioning, life satisfaction and depressive symptomatology (ps<0.05). The intervention group had a significantly greater increment in quality-adjusted life years (p<0.02), which was achieved cost-effectively (US $41 218/UK £24 868 per unit). No intervention effect was found for cognitive functioning outcome measures.
A lifestyle-oriented occupational therapy intervention has beneficial effects for ethnically diverse older people recruited from a wide array of community settings. Because the intervention is cost-effective and is applicable on a wide-scale basis, it has the potential to help reduce health decline and promote well-being in older people.
Trial Registration identifier: NCT0078634.
PMCID: PMC3412049  PMID: 21636614
Lifestyle interventions; occupational therapy; randomised controlled trial; quality of life; ageing/geriatrics; depression; geriatrics; lifestyle; qual of life measmnt; randomised trials
25.  Collaborative Depression Treatment in Older and Younger Adults with Physical Illness: Pooled Comparative Analysis of Three Randomized Clinical Trials 
There have been few comparisons of the effectiveness of collaborative depression care between older versus younger adults with co-morbid illness, particularly among low-income populations.
Intent-to-treat analyses are conducted on pooled data from three randomized controlled trials that tested collaborative care aimed at improving depression, quality of life and treatment receipt.
Trials were conducted in oncology and primary care safety net clinics and diverse home health care programs.
1,081 patients with major depressive symptoms and cancer, diabetes or other co-morbid illness.
Similar intervention protocols included patient, provider, socio-cultural and organizational adaptations.
The PHQ-9 depression, SF-12/20 quality-of-life, self-reported hospitalization, ER, ICU utilization, and antidepressant, psychotherapy treatment receipt are assessed at baseline, 6, 12 months.
There are no significant differences in reducing depression symptoms (P ranged 0.18-0.58), improving quality-of-life (t=1.86, df=669, P=0.07 for physical functioning at 12 months; and P ranged 0.23-0.99 for all others) between patients ≥60 versus 18-59. Both age group intervention patients have significantly higher rates of a 50% PHQ-9 reduction (older: Wald χ2[df=1]=4.82, p=0.03; younger: Wald χ2[df=1]=6.47, p=0.02), greater reduction in major depression rates (older: Wald χ2[df=1]=7.72, p=0.01; younger: Wald χ2[df=1]=4.0, p=0.05) than enhanced-usual-care patients at 6 months, and are no significant age group differences in treatment type or intensity.
Collaborative depression care in individuals with co-morbid illness is as effective in reducing depression in older patients as younger patients, including among low-income, minority patients. Patient, provider, and organizational adaptations of depression care management models may contribute to positive outcomes.
PMCID: PMC2875343  PMID: 20220588
collaborative multidisciplinary care; depression; comorbid illness; diabetes; cancer; home health

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