Jimi Huh

University of Southern California | USC · Institute for Health Promotion and Disease Prevention Research

A community-based qualitative study identified multilevel influences on sleep duration, quality, and timing in 10 to 12-year-old Latino pre-adolescents via 11 focus groups with 46 children and 15 interviews with parents. An iterative content analysis revealed three themes negatively and positively impacted sleep: (1) Individual-level; (2) Social-le...

Attention Deficit Hyperactivity Disorder (ADHD) is associated with emotional regulation and cognitive processing challenges throughout life. Not well-understood is how ADHD genetic risk (ADHD-GR) affects depressive symptoms (DepSx) and cognitive functioning in older age. Furthermore, less is known about the mechanisms through which some individuals...

Vape shops specialize in sales of e-cigarettes and related products. This study examines whether vape shops adapted their products and services in response to changes in federal and state policies that affect the tobacco retail environment between 2014–2022. In this multicohort study, four waves of study data were used to examine the trends in prod...

Background: Just-in-time adaptive interventions (JITAIs) in mobile health are an intervention design that provides behavior change support based on an individual's changing and dynamic contextual state. However, few studies have documented how end users of JITAI technologies are involved in their development, particularly from historically margina...

Background: Previous studies on affective state-sedentary behavior (SB) associations have not accounted for their potentially time-varying nature and have used inconsistent SB measurement modalities. We investigated whether the strength of the associations between affective states and SB varied as a function of the time of day and by SB measuremen...

Vape shops specialize in the sales of e-cigarettes and other vaping products. In recent studies, young adults who use e-cigarettes have tended to identify with at-risk peer crowds. This is the first study to examine vape shop customers' clientele. Composed primarily of young adults and persons in early middle adulthood, we speculated that a relativ...

BACKGROUND: Medical mistrust can be a barrier to healthcare utilization. While the Group-Based Medical Mistrust Scale (GBMMS) has been validated among diverse populations, we know little about its psychometric performance among English-Speaking (ES) and Spanish-Speaking (SS) Latinos. We aim to examine the factor structure of GBMMS among Latino pare...

Objectives: To explain the ethnic paradox of mental health in aging, we evaluated whether Black and Latinx older adults experience (1) fewer depressive symptoms (DepSx), but more physical problems, and (2) greater psychological resilience as a result of life stressors than White older adults. Methods: DepSx, physical health, and recent stress we...

Objective: We examined the within-person longitudinal and bidirectional associations between patterns of sedentary time accumulation [alpha (sedentary bout duration/length), sedentary breaks (number of breaks in sedentary bouts)], and symptoms of major depressive disorder and generalized anxiety disorder. Methods: Children [N = 167, 10.1(0.9) ye...

BACKGROUND Previous studies on affective state–sedentary behavior (SB) associations have not accounted for their potentially time-varying nature and have used inconsistent SB measurement modalities. We investigated whether the strength of the associations between affective states and SB varied as a function of the time of day and by SB measurement...

Purpose: Considerable evidence has shown that social networks influence a wide variety of health behaviors. This study investigates whether having friends with overweight/obesity in one's social network (network exposure) can predict changes in body mass index (BMI) throughout high school in a diverse urban population of students. Methods: Racially...

Objectives In February 2020, the US Food and Drug Administration issued a guidance restricting the sales and distribution of cartridge-based e-cigarettes with flavours other than tobacco and menthol. Disposable devices were exempt from this guidance. This study examined the prevalence of disposable pod use and flavour preference compared with refil...

Objective The 2016 FDA’s “Deeming Rule” prohibited free samples of vaping products. The purpose of this study was to investigate compliance with or adaptation to this newly established FDA policy. Methods Vape shops were recruited in Southern California between November 2017 and December 2018. Data collectors interviewed 121 vape shop employees, w...

Introduction E-cigarette users typically initiate vaping with flavoured e-liquids. People who vape flavours tend to underestimate the harm of vaping. We examined the inter-relationship between flavour preference, vaping for cessation purposes, e-cigarette dependence, e-cigarette harm perception and purchase/use intention, given a hypothetical flavo...

Children are a priority population for skin cancer prevention as excessive sun exposure in childhood increases the risk of melanoma in adulthood. The complexity of sun protective behaviors has posed measurement challenges for trials testing intervention efficacy. The current study evaluated a sun safety intervention for schoolchildren using latent...

Background In this study, we describe a participatory design process to develop a technology-based intervention for sun protection for children and their parents. Our methodology embraces and leverages the expert knowledge of the target users, children and their parents, about their sun protection practices to directly influence the design of our m...

Introduction This study examined vape shop customers’ behaviors in relation to shop display practices. We hypothesized that display of signs conveying supportive attitude toward vaping at vape shops would be positively associated with customer purchasing and in-shop vaping behaviors. Methods We recruited vape shops throughout Southern California (...

Most children in the United States currently do not meet physical activity (PA) guidelines, and perceived stress is a known barrier against PA. However, most studies have solely focused on the between-subject (BS) association of stress and PA, whereas the within-subject (WS) relationship remains under-studied in children. This limits our understand...

Introduction Past studies have documented disparities in regulation compliance among tobacco retailers with respect to ethnic diversity in neighbourhoods. This study investigated the association between compliance with the Food and Drug Administration (FDA) and California state rules and neighbourhood ethnic composition of a vape shop location. Me...

Our ability to understand and intervene on eating in the absence of hunger (EAH) as it occurs in peoples' natural environments is hindered by biased methods that lack ecological validity. One promising indicator of EAH that does not rely on self-report and is easily assessed in free-living individuals is glucose. Here, we hypothesize that elevated...

The 1st cigarette of the day is strongly tied to tobacco dependence. However, prior research has not investigated whether within-subject (WS) day-to-day fluctuations in prefirst-cigarette affect are associated with the subjective effects from the 1st cigarette of the day or whether these associations differ by smokers' average prefirst-cigarette af...

Abstract Background Research has shown that affect is associated with everyday movement behaviors in children and adults. However, limited work to date has investigated dyadic influences of momentary affect on moderate-to-vigorous physical activity (MVPA) and sedentary time among children and their mothers using ecological momentary assessment (EMA...

Background To identify actionable and effective implementation intention (II) plans, we examined whether (a) IIs suggesting food or nicotine-based substitution strategies to help quit smoking cigarettes would be more likely to be enacted in real time, (b) IIs reminding participants to cognitively motivate themselves or engage in solitary activity w...

Objective Circulating glucose may relate to affective and physical feeling states reflective of emotional disorder symptoms. No prior studies have investigated within-day associations between glucose and subsequent affective and physical feeling states (positive affect, negative affect, and fatigue) as they occur naturally among healthy adolescents...

Identifying vulnerable windows for a given problematic behavior and providing timely and appropriate support are critical for building an effective just-in-time (JIT) intervention for behavioral change. We developed and evaluated an implementation intention (II) based, JIT cessation intervention prototype to support Asian American young adult smoke...

Objectives Mothers report higher levels of psychological stress than fathers. s. Psychological stress is posited to influence parenting practices that could increase children’s obesity risk. However, previous studies have not investigated several aspects of maternal mental health and the moderating role of household structure on children’s obesity...

Background: Momentary affect and stress in mothers and their children may be an important predictor of food intake in the natural environment. This study hypothesized that there would be parallel actor and partner effects such that mothers' and children's negative affect (NA), positive affect (PA), and ability to cope with stress would be associat...

This pilot study tested a novel human laboratory model for estimating the extent to which electronic cigarettes (e-cigarettes) serve as motivational substitutes for combustible cigarettes. The model assesses 3 parameters of substitutability, including the: (a) increase in motivational reward value of e-cigarettes after tobacco deprivation; (b) redu...

Background Few studies have examined the role of maternal stress in relation to their children’s dietary quality and its trajectory over time. Purpose The objective of this longitudinal study was to examine the effect of baseline maternal stress on the change in their 8- to 12-year-old children’s dietary quality over 1 year. Methods Mother–child...

Background Previous studies demonstrated a positive association between perceived discrimination and mental health problems among immigrants in countries that traditionally host immigrants. Recent trends in international migration show that there has been a significant increase in immigrant populations in East Asian countries. These newer host coun...

Objective: We examined the acute bidirectional relationships between affective states and moderate-to-vigorous physical activity (MVPA) or sedentary behavior (SB) in children, and whether perceived stress moderates these associations. Method: A total of 180 children (mean age = 9.6 years, 51.7% female, 53.9% Hispanic) completed a 7-day ecologica...

Affective volatility (i.e., variability) is typically conceptualized as a marker of poor mental and behavioral health. The current research challenges this notion. Among individuals who typically experience low positive affect (PA), vacillation between bouts of joy and marked anhedonia may be associated with better behavioral health relative to a r...

BACKGROUND New methods for assessing diet in research are being developed to address the limitations of traditional dietary assessment methods. Mobile device–assisted ecological momentary diet assessment (mEMDA) is a new dietary assessment method that has not yet been optimized and has the potential to minimize recall biases and participant burden...

Background: New methods for assessing diet in research are being developed to address the limitations of traditional dietary assessment methods. Mobile device-assisted ecological momentary diet assessment (mEMDA) is a new dietary assessment method that has not yet been optimized and has the potential to minimize recall biases and participant burde...

Research is inconclusive about whether physical activity (PA) should be performed every day or performed less frequently but in longer bouts to obtain mental health benefits. The current study examined the extent to which day-to-day variability in PA is associated with adults' mental health, and if this association differed by Body Mass Index (BMI)...

Objectives Higher levels of positive affect and feelings of energy are associated with greater physical activity (PA) and lower sedentary time (ST). However, whether fluctuations in these feelings contribute to the regulation of these behaviors is unclear. This study examined the extent to which subject-level variability (i.e., degree of intraindiv...

Ecological momentary assessment (EMA) is a real-time sampling strategy that may address limitations in health research, such as the inability to examine how processes unfold on a daily basis. However, EMA studies are prone to limited data availability due to difficulties in implementing sophisticated protocols and systematic non-compliance with pro...

Background: To address the limitations of the retrospective self-reports of activity, such as its susceptibility to recall bias, researchers have shifted toward collecting real-time activity data on mobile devices via ecological momentary assessment (EMA). Although EMA is becoming increasingly common, it is not known how EMA self-reports of physica...

Although rates of late-stage melanoma are rising in Hispanics, particularly those living in high ultraviolet light environments, little is known about the prevalence of sun protective behaviors in Hispanic children. We analyzed baseline data including frequency of sunburn, sun protective behaviors, level of U.S. acculturation, and skin phototype fr...

Modeling intra-individual fluctuations in estradiol and progesterone may provide unique insight into the effects of ovarian hormones on the etiology and treatment of nicotine dependence. This randomized placebo-controlled laboratory study tested the independent and interactive effects of intra-individual ovarian hormone variation and nicotine on su...

More data continues to emerge on teen use of eCigarettes that leads to smoking. Renowned AAP journal editors have created this new, first-in-series, Pediatric Collection with high-impact articles that address the public health trend among adolescents and young adults, and the unintended nicotine poisonings among younger children. https://shop.aap.o...

High smoking prevalence among Korean American (KA) males place KA family members and co-workers at an elevated risk of involuntary tobacco smoke exposure (ITSE). KA emerging adults (EAs) face an additional risk of ITSE by their peers, as emerging adulthood is associated with increased smoking. This paper explores health behaviors, attitudes and bel...

Current knowledge about the relationship of physical activity with acute affective and physical feeling states is informed largely by lab-based studies, which have limited generalizability to the natural ecology. This study used ecological momentary assessment to assess subjective affective and physical feeling states in free-living settings across...

Background: The impact of sugar restriction on subsequent sugar intake by overweight adolescents is unknown. Objective: Our aim was to examine the effect of sugar restriction on subsequent ad libitum sugar intake by overweight adolescents and whether habitual sugar intake and impulsivity influence the effect of sugar restriction on subsequent su...

Recently, an addiction matrix measure was assessed among U.S. former alternative high school youth. This presentation seeks to examine the generalizability of findings using this measure among Russian and Spanish high school adolescents. Latent class analysis was used to explore addiction subgroups among adolescents in Russia (average age=16.27; n=...

Background: Physical activity and diet are major modifiable health behaviors contributing to obesity risk. Although patterns of these behaviors tend to cluster within individuals and within family units, it is unknown to what extent healthy and unhealthy dietary intake might differentially accompany sedentary and physical activities in mothers com...

Research attempting to elucidate physical activity (PA) intention-behavior relations has focused on differences in long-term behavior forecasting between people. However, regular PA requires a repeated performance on a daily or within-daily basis. An empirical case study application is presented using intensive longitudinal data from a study of PA...

Purpose: Cigarette smoking is a preventable risk factor that contributes to unnecessary lung cancer burden among Korean Americans and there is limited research on effective smoking cessation strategies for this population. Smartphone-based smoking cessation apps that leverage just-in-time adaptive interventions (JITAIs) hold promise for smokers at...

Purpose: Affective response during physical activity may influence motivation to perform future physical activity behavior. However, affective response during physical activity is often assessed under controlled laboratory conditions. The current study used ecological momentary assessment (EMA) to capture affective responses during free-living phy...

Background/purpose: Rates of melanoma are rising in Hispanics in the United States. Excessive sun exposure in childhood increases the risk of melanoma in adulthood, and little is known about the factors motivating sun protection behaviors among Hispanic youth. Methods: Correlates of sun protection were examined among Hispanic children residing i...

Perceived smoking prevalence, a strong predictor of actual smoking behavior, may be influenced by the ethnicity and gender of the reference group presented to Korean American emerging adults. Self-identifying Korean and Korean Americans aged 18-25 (N = 475), were invited to complete a 15-20 min online survey about their attitudes towards smoking. P...

Background Dietary fiber and sugar intake have been shown to affect metabolic health in overweight Hispanic youth. Evidence on the influence of culture on fiber and sugar intake in Hispanic youth is limited. Methods The associations among score for levels of assimilation, neighborhood ethnic characteristics, and daily total and added dietary sugar...

This study used time-varying effect modeling to examine time of day differences in how behavioral cognitions predict subsequent physical activity (PA). Adults (N =116) participated in three, four-day "bursts" of Ecological Momentary Assessment (EMA). Participants were prompted with eight EMA questionnaires/day assessing behavioral cognitions (i.e.,...

Internet addiction (including online gaming) has been associated with depression. However, most prior research relating internet addiction symptomatology to depressive symptoms has been cross-sectional, conducted with children and adolescents, and only examined depressive symptoms as a broad construct. The purpose of the current study was to examin...

Background and aims: This study used Ecological Momentary Assessment (EMA) in mother-child dyads to examine the day-level associations of stress and eating. Method: Mothers and their 8- to 12-year-old children (N = 167 dyads) completed between three (weekday) and eight (weekend) EMA survey prompts per day at random nonschool times across 8 days....

The present study provides detailed contextual information about smoking habits among young Korean American smokers with the goal of characterizing situations where they are most at risk for smoking. Relevant situational factors included location, social context, concurrent activities, time of day, affective states, and food and beverage consumptio...

Purpose: One concern regarding the recent increase in adolescent e-cigarette use is the possibility that electronic (e-) cigarettes may be used by those who might not otherwise have used cigarettes, and that dual use, or transition to cigarette use alone, may follow. Methods: Questionnaire data were obtained in 2014 from 11th/12th grade students...

Introduction: Diverse patterns of adolescent use and poly-use of tobacco products other than conventional cigarettes are emerging. Data characterizing common patterns of youth tobacco product use and typical transitions among patterns may inform tobacco control policy and prevention. This study identified common patterns of use and poly-use of fiv...

Given that prior research implicates smoking abstinence in increased premenstrual symptoms, tobacco withdrawal, and smoking behaviors, it is possible that women with more severe premenstrual symptoms have stronger expectancies about the effects of smoking and abstaining from smoking on mood and withdrawal. However, such relations have not been prev...

Introduction: Korean American emerging adult (KAEA) smokers represent a culturally and developmentally unique population constituted of primarily light, intermittent smokers. Sociocultural contexts might play an important role in contributing to instances of acute cigarette craving and motivation to smoke in this population; yet, research testing...

Critical gaps exist in understanding the patterns and correlates of dual use of electronic cigarettes (ECs) and combustible cigarettes (CCs), particularly in ethnic minority populations. In this study, we assessed CC and EC use in the naturalistic environment using ecological momentary assessment (EMA). We hypothesized that within-subject variation...

Purpose: There is a growing public health concern related to the rapid increase in the use of multiple tobacco products among adolescents. This study examined patterns of adolescent use of cigarettes, e-cigarettes, cigars/cigarillo, hookah/waterpipe, and smokeless/dip/chewing tobacco in a population of southern California adolescents. Methods: D...

Introduction: Persistent tobacco use among racial and ethnic minority populations in the United States is a critical public health concern. Yet, potential sources of racial/ethnic disparities in tobacco use remain unclear. The present study examined racial/ethnic differences in tobacco withdrawal-a clinically-relevant underpinning of tobacco use t...

The current study used a novel real-time data capture strategy, ecological momentary assessment (EMA), to examine whether within-day variability in stress and context leads to exacerbations in asthma symptomatology in the everyday lives of ethnic minority adolescents. Low-income Hispanic adolescents (N = 20; 7th-12th grade; 54% male) with chronic a...

Decisions to perform moderate to vigorous physical activity (MVPA) involve behavioral cognitive processes that may differ within individuals depending on the situation. Ecological momentary assessment (EMA) was used to examine the relationships of momentary behavioral cognitions (i.e., self-efficacy, outcome expectancy, intentions) with MVPA (measu...

This crossover experimental study examined the acute effects of high-sugar/low-fiber (HSLF) vs. low-sugar/high-fiber (LSHF) meals on sedentary behavior (SB) and light-plus activity (L+) in minority adolescents with overweight and obesity. 87 Latino and African American adolescents (mean age = 16.3 ± 1.2 years, mean BMI z-score = 2.02 ± 0.52, 56.8%...

Use of electronic cigarettes (e-cigarettes) among adolescents has increased since their introduction into the US market in 2007. Little is known about the role of e-cigarette psychosocial factors on risk of e-cigarette or cigarette use in adolescence. Information on e-cigarette and cigarette psychosocial factors (use and attitudes about use in the...

Higher positive and lower negative affective response during physical activity may reinforce motivation to engage in future activity. However, affective response during physical activity is typically examined under controlled laboratory conditions. This research used ecological momentary assessment (EMA) to examine social and physical contextual in...

Little is known about the relationship between dietary intake and affective and physical feeling states in children. The current study used Ecological Momentary Assessment (EMA) to examine how usual dietary intake is cross-sectionally associated with both average affective and physical feeling state ratings and rating variability in children. Child...

Parental stress is an understudied factor that may compromise parenting practices related to children's dietary intake, physical activity, and obesity. However, studies examining these associations have been subject to methodological limitations, including cross-sectional designs, retrospective measures, a lack of stress biomarkers, and the tendenc...

Examine the association between perceived stress and hunger continuously over a week in free-living individuals. Forty five young adults (70% women, 30% overweight/obese) ages 18 to 24 years (Mean=20.7, SD=1.5), with BMI between 17.4 and 36.3 kg/m(2) (Mean=23.6, SD=4.0) provided between 513-577 concurrent ratings of perceived stress and hunger for...

Three community-based CHWs/Promotoras de Salud-academic research partnerships explore how neighborhood characteristics (rural vs. urban) are associated with equity indicators in vulnerable communities; and how CHWs/Promotras can use these indicators to maximize community change: Regale-Salud, Su-Corazón-Su-Vida, and Tobacco-Retailers engaged CHWs/P...

Background: Maternal stress plays a significant role in the development and progression of cervical cancer. We examined whether being overwhelmed with “too much to deal with” impacts being up-to-date with Pap-testing, having one’s daughter vaccinated against HPV and self-efficacy to engage in these behaviors. Using a place-based framework, we exami...

A sequential mixed methods study was conducted to identify factors influencing perceived norms about smoking and to examine the association of acculturative contexts and normative beliefs among Korean American young adults (KAYA) who face increased risk of smoking. Content analysis of data from 67 participants in 10 focus groups in 2010 led to the...

Social network analysis was used to examine whether peer influence from one's social networks moderates obesity prevention program effects on obesity-related behaviors: healthful and unhealthful. Participants included 557 children residing in Southern California. The survey assessed health-promoting behaviors (i.e., physical activity at school, phy...

Korean Americans represent one of the fastest growing Asian subpopulations in the United States. Despite a dramatic reduction in incidence nationwide, cervical cancer remains a major threat for Korean American women. By preventing the strains of the Human Papillomavirus (HPV) known to cause cervical cancer, the HPV vaccines appear to be a promising...

The objective of this study was to determine contextual antecedents to smoking among Korean American emerging adult (KAEA) smokers, using ecological momentary assessment. Based on extant theory and data documenting the importance of negative affect (NA) and social context, we examined the extent to which being with friends and NA independently and...

People are embedded in a complex socio-spatial context that may affect their weight status through multiple mechanisms, including food and physical activity opportunities and chronic stress exposure. However, research to date has been unable to resolve what features of neighborhoods are causally related to weight status. We used latent profile anal...