Smartphone GPS-Based Exposure to Greenspace and Walkability and Accelerometer-Assessed Physical Activity During Pregnancy and Early Postpartum-Evidence from the MADRES Cohort.

A growing number of studies have associated walkability and greenspace exposure with greater physical activity (PA) in women during pregnancy. However, most studies have focused on examining women's residential environments and neglected exposure in locations outside the home neighborhood. Using 350 person-days (N = 55 participants) of smartphone global positioning system (GPS) location and accelerometer data collected during the first and third trimesters and 4-6 months postpartum from 55 Hispanic pregnant women from the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) study, we examined the day-level effect of women's exposure to walkability and greenspace on their PA outcomes during pregnancy and in the early postpartum period. Moderate-to-vigorous physical activity [MVPA] minutes per day was assessed using accelerometers. Walkability and greenspace were measured using geographic information systems (GIS) within women's daily activity spaces (i.e., places visited and routes taken) recorded using a smartphone GPS and weighted by time spent. We used a generalized linear mixed-effects model to estimate the effects of daily GPS-derived environmental exposures on day-level MVPA minutes. Results showed that women engaged in 23% more MVPA minutes on days when they had some versus no exposure to parks and open spaces in activity spaces (b = 1.23; 95%CI: 1.02-1.48). In addition, protective effects of daily greenspace and walkability exposure on MVPA were stronger in the first and third trimesters, among first-time mothers, and among women who had high pre-pregnancy body mass index (BMI) and lived in least-safe neighborhoods. Our results suggest that daily greenspace and walkability exposure are important for women's PA and associated health outcomes during pregnancy and early postpartum.

Organophosphate ester flame retardant chemicals and maternal depression during pregnancy.

BACKGROUND: Depression substantially contributes to pregnancy-related morbidity, and pregnancy is increasingly recognized as a vulnerable window for exposure effects on maternal mental health. Exposures to organophosphate esters (OPEs) are ubiquitous and may have neurotoxic effects; however, their impacts on prenatal depression remain unknown. We evaluated associations of third trimester OPE metabolites on maternal depressive symptoms during pregnancy. METHODS: This study included 422 participants in the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) cohort, a prospective pregnancy cohort of primarily low-income and Hispanic participants residing in Los Angeles, California. We measured concentrations of nine OPEs in third trimester spot urine samples (mean gestational age = 31.5 ± 2.0 weeks). Using the Center for Epidemiologic Studies-Depression (CES-D) scale, we classified participants as having probable depression during pregnancy (N = 137) or not (N = 285) if one or more CES-D scores administered at each trimester met the suggested cutoff score for clinically significant depressive symptoms (≥16). We estimated associations of prenatal OPE metabolite concentrations in tertiles and risk of prenatal depression using modified Log-Poisson regression. We examined associations of the OPE mixture on depression during pregnancy using Bayesian kernel machine regression (BKMR). RESULTS: Participants with the highest tertiles of DPHP and BDCIPP exposure had a 67% (95% CI: 22%, 128%) and 47% (95% CI: 4%, 108%) increased risk of maternal depressive symptoms during pregnancy, respectively. No associations between other OPE metabolites and maternal depression symptoms were observed. In mixture analyses, we observed a positive and linear association between higher exposure to the OPE metabolite mixture and odds of prenatal maternal depression, primarily driven by DPHP. CONCLUSIONS: Our findings provide new evidence of associations between frequently detected OPE metabolites on maternal depression symptoms during pregnancy. Results could inform future intervention efforts aimed at reducing perinatal maternal depression.

The temporal stability of maternal parenting style and child feeding practices: A six-wave longitudinal study.

Although parenting styles and child feeding practices are conceptualized as distal, static predictors of child eating and weight outcomes, few studies have examined the temporal stability (i.e., change over time) of these parenting measures. Also, parental characteristics, such as mental health or socio-demographics, may make it more or less difficult to sustain consistent parenting behavior. This study examined the temporal stability of parenting styles and child feeding practices and the association between temporal stability indices with maternal sociodemographic and mental health characteristics. The analytic sample included 161 ethnically diverse mothers enrolled in a six-wave bi-annual longitudinal study. During each wave, mothers reported on their parenting styles and child feeding practices using validated self-report questionnaires. Temporal stability indices for parenting styles were moderate for authoritative (ICC = 0.57) and authoritarian (ICC = 0.70) styles, yet high for permissive (ICC = 0.78) styles. Temporal stability scores for child feeding practices were low for discipline (ICC = 0.33), limit setting (ICC = 0.33), monitoring (ICC = 0.36), and pressure to eat (ICC = 0.34); however, restriction (ICC = 0.53) and role modeling of healthy eating were moderate (ICC = 0.73). Greater income and education status were positively associated with stability in authoritative, authoritarian, and permissive parenting styles, as well as with limit setting, monitoring, role modeling of healthy eating, and pressure to eat feeding practices. Higher anxiety and depressive symptoms and lower self-esteem were negatively associated with permissive parenting styles and role modeling of healthy eating. Findings show that maternal parenting styles and child feeding practices fluctuate over time, and sociodemographic and mental health characteristics are related to stability of some of these parenting styles and behaviors.

Personal and Social-Built Environmental Factors of Glucose Variability Among Multiethnic Groups of Adults With Type 2 Diabetes: Research Protocol Using Ecological Momentary Assessment, Continuous Glucose Monitoring, and Actigraphy.

Glucose variability (GV)-the degree of fluctuation in glucose levels over a certain period of time-is emerging as an important parameter of dynamic glycemic control. Repeated glycemic oscillations have been reported to be the link to diabetes complications. This prospective observational study aims to: (1) identify multilevel risk factors (personal and social-built environmental factors) associated with high GV; (2) identify "within-person predictors" of high GV leveraging the intra-person data to inform future personalized diabetes interventions; and (3) examine which lifestyle factors either mediate or moderate the relationship between emotional well-being and GV among diverse adults with type 2 diabetes (T2D). We will recruit 200 adults with T2D from the community. All participants will complete baseline surveys assessing demographics, lifestyle, social-built environmental, and clinical factors. Real-time dynamic glucose levels will be measured using continuous glucose monitoring (CGM). Sleep, physical activity, diet/eating, and emotional well-being will be measured with an actigraphy device and a real-time self-report tool (ecological momentary assessment [EMA]) across 14 days. Two 24-h dietary recall data will be collected by online video calls. Generalized linear models, multilevel models, and structural equation models will be developed to achieve the study aims. The findings from the study will identify high-risk groups of high GV who would benefit from CGM to improve diabetes outcomes and inform the future development of personalized just-in-time interventions targeting lifestyle behaviors with an increased understanding of GV and by supporting healthcare providers' clinical decisions.

A Vegetable, Oil, and Fruit Dietary Pattern in Late Pregnancy is Linked to Reduced Risks of Adverse Birth Outcomes in a Predominantly Low-Income Hispanic and Latina Pregnancy Cohort.

BACKGROUND: Studies examining diet and its links to birth outcomes among socioeconomically disadvantaged populations in the United States are scarce. OBJECTIVES: We aimed to identify prenatal dietary patterns, examine their relationships with birth outcomes, and evaluate the variation of these associations by maternal diabetes status [no diabetes, gestational diabetes mellitus (GDM), preexisting diabetes]. METHODS: Women in the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) study (n = 465)-an ongoing, prospective pregnancy cohort of predominantly low-income Hispanic/Latina women in Los Angeles-completed up to two 24-hour dietary recalls in the third trimester of pregnancy. We identified prenatal dietary patterns via factor analysis and evaluated their associations with infant birth weight and gestational age at birth (GA) z-scores, separately, using linear regression, as well as the associations of the dietary patterns with premature births, having an infant that was small for gestational age (SGA), and having an infant that was large for gestational age, using logistic regression and adjusting for relevant covariates. We additionally tested interaction terms between prenatal dietary patterns and maternal diabetes status in separate models. We adjusted for multiple comparisons using the false discovery rate. RESULTS: We identified 2 dietary patterns: 1) a dietary pattern of solid fats, refined grains, and cheese (SRC); and 2) a dietary pattern of vegetables, oils, and fruit (VOF). Comparing the highest to lowest quartiles, the VOF was significantly associated with a greater infant birth weight (ß = 0.40; 95% CIs: 0.10, 0.70; Ptrend = 0.011), a greater GA (ß = 0.32; 95% CIs: 0.03, 0.61; Ptrend = 0.036), lower odds of a premature birth (OR = 0.31; 95% CIs: 0.10, 0.95; Ptrend = 0.049), and lower odds of having an infant that was SGA (OR = 0.18; 95% CIs: 0.06, 0.58; Ptrend = 0.028). Only among women with GDM, a 1-SD score increase in the prenatal SRC was significantly associated with a lower infant birth weight (ß = -0.20; 95% CIs -0.39, -0.02; Pinteraction = 0.040). CONCLUSIONS: Among low-income Hispanic/Latina pregnant women, greater adherence to the prenatal VOF may lower the risk of a premature birth and having an infant that is SGA. Greater adherence to the SRC, however, may adversely affect newborn birth weight among mothers with GDM, but future research is needed to verify our findings.

Depressive symptoms and physical activity among young adult survivors of childhood cancer.

OBJECTIVE: Young adult survivors of childhood cancers are less likely to be physically active compared to non-cancer affected controls, putting them at an increased risk for morbidity and mortality. Preliminary research has examined how mental health may contribute to physical activity (PA) in this population; however, those more recently diagnosed and Hispanic survivors have been understudied. The objectives were to examine associations of dimensions of depressive symptoms, demographic characteristics, and cancer-related predictors with PA among a diverse sample of young adult childhood cancer survivors. METHODS: Participants (N = 895) diagnosed with childhood cancer between 1996 and 2010 (53% Hispanic; Mage  = 26.2 ± 4.9 years; Mage  = 14.8 ± 4.4 years at diagnosis) were recruited from the Los Angeles County cancer registry. Self-report surveys assessed current PA, depressive symptoms (i.e., positive affect, negative affect, somatic symptoms, interpersonal problems), late effects of cancer treatment, and demographic factors. Multivariable ordinal regressions examined the study objectives. RESULTS: About 70% of participants engaged in low or moderate frequency PA (fewer than 3 days a week). Participants who were older, female, Asian, or reported more late effects of cancer treatment were less likely to engage in PA. Greater positive affect was significantly associated with higher frequency PA, whereas negative affect, somatic symptoms, and interpersonal problems were not associated with PA. CONCLUSIONS: The findings suggests that positive-but not negative-mental health characteristics are more likely to facilitate or result from PA among young adult survivors of childhood cancers. Interventions seeking to increase PA may benefit from considering positive aspects of mental health/well-being.

Affective Response During Real-World Physical Activity as an Intervention Mediator.

Some people experience pleasure during physical activity, whereas it can be unpleasant for others. Modifying affective responses during physical activity in real-world situations may be an intervention strategy for increasing physical activity. This article follows an experimental medicine framework to summarize evidence identifying, assessing, and influencing affective response during real-world physical activity to inform interventions targeting this mediating mechanism.

Sex-specific effects of prenatal organophosphate ester (OPE) metabolite mixtures and adverse infant birth outcomes in the maternal and developmental risks from environmental and social stressors (MADRES) pregnancy cohort.

BACKGROUND: Organophosphate esters (OPEs) are used as flame retardants and plasticizers in various consumer products. Limited prior research suggests sex-specific effects of prenatal OPE exposures on fetal development. We evaluated overall and sex-specific associations between prenatal OPE exposures and gestational age (GA) at birth and birthweight for gestational age (BW for GA) z-scores among the predominately low-income, Hispanic MADRES cohort. METHODS: Nine OPE metabolite concentrations were measured in 421 maternal urine samples collected during a third trimester visit (GA = 31.5 ± 2.0 weeks). We examined associations between single urinary OPE metabolites and GA at birth and BW for GA z-scores using linear regression models and Generalized Additive Models (GAMs) and effects from OPE mixtures using Bayesian Kernel Machine Regression (BKMR). We also assessed sex-specific differences in single metabolite analyses by evaluating statistical interactions and stratifying by sex. RESULTS: We did not find significant associations between individual OPE metabolites and birth outcomes in the full infant sample; however, we found that higher bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) was associated with earlier GA at birth among male infants (p = 0.04), and a nonlinear, inverted U-shape association between the sum of dibutyl phosphate and di-isobutyl phosphate (DNBP + DIBP) and GA at birth among female infants (p = 0.03). In mixtures analysis, higher OPE metabolite mixture exposures was associated with lower GA at birth, which was primarily driven by female infants. No associations were observed between OPE mixtures and BW for GA z-scores. CONCLUSION: Higher BDCIPP and DNBP + DIBP concentrations were associated with earlier GA at birth among male and female infants, respectively. Higher exposure to OPE mixtures was associated with earlier GA at birth, particularly among female infants. However, we saw no associations between prenatal OPEs and BW for GA. Our results suggest sex-specific impacts of prenatal OPE exposures on GA at birth.

Daily ovarian hormone exposure and loss of control eating in adolescent girls: A registered report.

OBJECTIVE: The daily biobehavioral factors that precipitate loss of control eating (LOCE) in adolescent girls are not well known. Ovarian hormone levels are key biological factors associated with the etiology of eating disorders in adolescent girls. Yet, models on how daily ovarian hormone exposure predicts LOCE in adolescent girls are underdeveloped. The goal of this study is to examine the daily patterns and mechanisms of ovarian hormone levels on LOCE across the menstrual cycle in adolescent girls and the mediating roles of food-related reward anticipation and response inhibition. Ecological momentary assessment (EMA) paired with daily hormonal sampling will be used to examine (1) daily associations between within-person hormones and LOCE, and (2) the mediating role of within-person food-related reward anticipation and response inhibition. METHODS: Normally cycling adolescent girls who have reached menarche will provide daily saliva samples for hormone analysis and complete EMA for 35 days. During EMA, girls will report LOCE and will complete task-based and self-report measures of food-related response inhibition and reward anticipation. DISCUSSION: This work has implications for the development of new real-world biobehavioral models of LOCE in adolescent girls, which will guide theory improvements and treatment for LOCE. Results will provide preliminary evidence for treatment targets for novel interventions for adolescent girls-for example, a response inhibition intervention. PUBLIC SIGNIFICANCE: Adolescent eating disorders are severe mental health conditions, often marked by loss of control eating. Estrogen and progesterone play a role in the development and persistence of loss of control eating. The current study will examine how daily exposure to estrogen and progesterone predicts loss of control eating in adolescent girls and identify possible daily mechanisms linking estrogen and progesterone exposure and loss of control eating.

Prenatal exposures to organophosphate ester metabolite mixtures and children's neurobehavioral outcomes in the MADRES pregnancy cohort.

BACKGROUND: Evidence suggests organophosphate esters (OPEs) are neurotoxic; however, the epidemiological literature remains scarce. We investigated whether prenatal exposures to OPEs were associated with child neurobehavior in the MADRES cohort. METHODS: We measured nine OPE metabolites in 204 maternal urine samples (gestational age at collection: 31.4 ± 1.8 weeks). Neurobehavior problems were assessed among 36-month-old children using the Child Behavior Checklist's (CBCL) three composite scales [internalizing, externalizing, and total problems]. We examined associations between tertiles of prenatal OPE metabolites (> 50% detection) and detect/non-detect categories (< 50% detection) and CBCL composite scales using linear regression and generalized additive models. We also examined mixtures for widely detected OPEs (n = 5) using Bayesian kernel machine regression. RESULTS: Maternal participants with detectable versus non-detectable levels of bis(2-methylphenyl) phosphate (BMPP) had children with 42% (95% CI: 4%, 96%) higher externalizing, 45% (-2%, 114%) higher internalizing, and 35% (3%, 78%) higher total problems. Participants in the second versus first tertile of bis(butoxethyl) phosphate (BBOEP) had children with 43% (-1%, 109%) higher externalizing scores. Bis(1-chloro-2-propyl) phosphate (BCIPP) and child sex had a statistically significant interaction in internalizing (p = 0.02) and total problems (p = 0.03) models, with 120% (23%, 295%) and 57% (6%, 134%) higher scores in the third versus first BCIPP tertile among males. Among females, detectable vs non-detectable levels of prenatal BMPP were associated with 69% higher externalizing scores (5%, 170%) while the third versus first tertile of prenatal BBOEP was associated with 45% lower total problems (-68%, -6%). Although the metabolite mixture and each CBCL outcome had null associations, we observed marginal associations between di-n-butyl phosphate and di-isobutyl phosphate (DNBP + DIBP) and higher internalizing scores (0.15; 95% CrI: -0.02, 0.32), holding other metabolites at their median. CONCLUSIONS: Our results generally suggest adverse and sex-specific effects of prenatal exposure to previously understudied OPEs on neurobehavioral outcomes in 36-month children, providing evidence of potential OPE neurotoxicity.

Exploring the Effects of Perceived Stress on the Within-Person Relationships Between Daily Activity Levels and Sleep in Women: An Ecological Momentary Assessment Study.

BACKGROUND: Many studies show positive bidirectional associations between physical activity (PA) and sleep at the between-person level. There is an increased interest in investigating these associations at the within-person level. Few studies examined the effects of time-varying moderators on the within-person bidirectional associations between PA and sleep. This study aimed to examine the bidirectional within-person day-level associations between activity levels and self-reported sleep duration and explore the moderating effects of perceived stress on these day-level associations. METHOD: Data from 158 women that included 7-day free-living monitoring over 4 measurement periods was analyzed using multilevel modeling to explore the moderating effects of daily stress on the bidirectional, within-person associations between activity levels and self-reported sleep duration. Moderate-to-vigorous PA (MVPA) and sedentary behavior (SB) were estimated from a waist-worn accelerometer. Self-reported sleep duration and perceived stress were collected by ecological momentary assessment. RESULTS: No significant within-person associations between MVPA minutes and self-reported sleep duration were found in either direction. However, engaging in more MVPA than one's usual level was associated with longer sleep later that night when perceived stress was higher than usual (p = .04). Bidirectional negative within-person association between SB minutes and self-reported sleep duration was found (ps < .01). The negative association between SB and sleep duration later that night was stronger when perceived stress was lower than usual (p = .01). CONCLUSION: Daily stress played an important role in the day-to-day associations between activity levels and sleep.

Bidirectional Associations Between Physical Activity and Pain Among Older Adults: An Ecological Momentary Assessment Study.

This paper examines the within-day, bidirectional associations between physical activity and self-reported pain among older adults. Older adults (N = 104; range: 60-98 years) participated in a 10-day Ecological Momentary Assessment (EMA) study. Participants received six EMA prompts/day with a single item assessing pain. Participants wore an activPAL monitor measuring step counts. At the within-person level, on occasions when participants took more steps than usual in the 30 min before the EMA prompt, they were more likely to experience pain at the prompt (ß^02=0.0003, p < .03). At the between-person level, greater step counts in the 30 min before the EMA prompt, on average, were associated with less pain on occasions when pain was experienced (ß^01=-0.0005, p < .04). Pain was not related to subsequent stepping. Bidirectional associations between physical activity and pain were not documented, but physical activity did appear to be related to subsequent pain.

Third trimester cortisol is positively associated with gestational weight gain in pregnant women with class one obesity.

BACKGROUND/OBJECTIVE: Prevalence of pre-pregnancy obesity and excessive gestational weight gain (GWG) are higher among women of color with low SES. Dysregulation of the Hypothalamic-Pituitary-Adrenal (HPA) axis and its end-product, cortisol, during pregnancy is hypothesized to be associated with excessive GWG. However, past studies have produced inconsistent findings and often did not include health disparities populations. This study examined the association between pre-pregnancy body mass index (BMI), third trimester diurnal cortisol, and GWG in low-income, predominantly Hispanic women. SUBJECTS/METHODS: The MADRES study is an ongoing prospective cohort study of primarily Hispanic, low-income pregnant women and their children in Los Angeles, California. Data from 176 participants were included in this study. Total cortisol secretion (area under the curve, AUC) was quantified using four salivary cortisol samples (awakening, 30 min after awakening, afternoon, and bedtime) that were collected at home on one day during the third trimester of pregnancy. Moderation of the association between total cortisol and GWG by pre-pregnancy BMI was tested using multiple linear regression with a multiplicative interaction term. RESULTS: There was no association between total cortisol secretion and GWG overall (p = 0.82), but the association between total cortisol and GWG was stronger for women with class 1 pre-pregnancy obesity compared to women with normal pre-pregnancy BMI (interaction term p = 0.04). CONCLUSIONS: Results suggest that obesity status before pregnancy may be exacerbating the physiological impact of cortisol on GWG.

Transactional links between children daily emotions and internalizing symptoms: a six-wave ecological momentary assessment study.

BACKGROUND: This study explored the cross-sectional and longitudinal associations between everyday emotion dimensions and internalizing symptoms during the transition to early adolescence. We tested associations between children's intensity and instability of daily negative emotions (NE), positive emotions (PE), and daily NE differentiation (NED) with children's self-reported and their mothers' report of children's internalizing symptoms, across six waves, each wave separated by six months. METHODS: The sample included 199 ethnically diverse mother [Mage at baseline = 40.1 years (SD = 6.1] and child [Mage at baseline = 10.1 (SD = 0.90), 51% girls] dyads, who participated in six 7-day waves of ecological momentary assessment (EMA). During each wave, children reported on PE (i.e. happy and joyful) and NE (i.e. mad, sad, and stressed) up to eight random times per day through smartphone-based EMA. Children and mothers reported on children's internalizing symptoms at each wave. We used random-intercept cross-lagged panel models (RI-CLPMs) to test within- and between-person effects. RESULTS: At the within-person level, increased NE and decreased PE intensity, more unstable NE and PE, and decreased NED at any given wave were positively associated with children's self-reported internalizing symptoms but not with mother-reported child symptoms. However, emotion dimensions did not predict child-reported nor mother-reported child symptoms at the next wave. At the between-person level, higher average NE, more unstable PE and NE, and lower NED were positively associated with average child-reported and mother-reported child internalizing symptoms. CONCLUSIONS: This study suggests that emotional intensity, instability, and differentiation could be conceptualized as manifestations of internalizing symptoms but not as risk factors for its progression, or residual manifestations of it, among typical children.

Household pesticide exposures and infant gross motor development in the MADRES cohort.

BACKGROUND: The development of motor skills in infancy is a vital neurodevelopmental milestone. Although previous studies have explored the neurotoxic effects of agricultural pesticides on infants' motor development, limited research has examined early postnatal household pesticide use on infants' motor development, particularly among urban communities. OBJECTIVE: This study examined the association between early postnatal household pesticide use and infants' gross and fine motor development at 6 months of age. METHODS: Questionnaires were administered via telephone to 296 mother-infant dyads in the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) pregnancy cohort. Early life household pesticide use was assessed via questionnaire administered when infants turned 3 months old and gross and fine motor development was assessed by the Ages and Stages Questionnaire (ASQ-3) at 6 months old. Infant gross motor scores were reverse coded so that higher scores indicated lower gross motor performance. Negative binomial regressions were performed to assess the relationship between household pesticide use and infant gross motor development. RESULTS: Infants were predominantly Hispanic (78.7%) and full term (gestational age at birth: 39.0 ± 1.9 weeks), with 22.3% of maternal participants reporting household use of rodent and insect pesticides. Adjusting for recruitment site, maternal age, ethnicity, household income, education, infant corrected age, infant sex, and home type, infants with maternal-reported household use of rodent and insect pesticides had 1.30 times higher expected gross motor scores (95% confiidence interval 1.05, 1.61) than infants with no reported use of household pesticides, with higher scores indicating reduced gross motor performance. CONCLUSIONS: Our results suggest household use of rodent and insect pesticides may harm infants' gross motor development in early childhood. Future research should evaluate the impact of specific household chemicals in infant biospecimens and their associations with infant motor development to confirm these findings.

Patterns of Objectively Measured Sedentary Time and Emotional Disorder Symptoms Among Youth.

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) years old, 54.5% female, 59.3% Hispanic, 35.9% overweight/obese at baseline] participated in a 3-year longitudinal study that consisted of assessments of sedentary time, and depressive and anxiety symptoms. At each assessment, participants wore accelerometers and completed the Revised Child Anxiety and Depression Scale. Separate random intercept cross-lagged panel models estimated the within-person longitudinal and bidirectional associations between alpha, sedentary breaks, and symptoms of major depressive disorder and generalized anxiety disorder across chronological age intervals. RESULTS: Having greater than one's own usual depressive symptoms at age 11 was associated with fewer sedentary breaks 1 year later. Having greater than one's own usual generalized anxiety symptoms at age 11 was associated with longer sedentary bouts and fewer sedentary breaks 1 year later. In contrast, having greater than one's own usual sedentary breaks at age 10 was associated with fewer generalized anxiety symptoms 1 year later. All other associations, including at younger ages, were null. CONCLUSION: Deviations from one's usual levels of depressive or anxiety symptoms may be important for how sedentary time is subsequently accumulated. Intraindividual processes appear to be at play, therefore more within-person research is needed. Intervention strategies for promoting a healthier accumulation of sedentary time may consider targeting occasions when depressive and anxiety symptoms are greater than usual.

Day-level associations of physical activity and sedentary time in mother-child dyads across three years: a multi-wave longitudinal study using accelerometers.

Understanding associations between mothers' and children's physical activity and sedentary behavior on more fine-grained timescales can provide insights into real-time intervention opportunities. This study examined the extent to which mothers' and their children's device-measured moderate-to-vigorous physical activity (MVPA) and sedentary time (SDT) were associated at the day level during non-school time. Mother-child dyads (N = 193; baseline Mean ages = 40.69 ± 6.11 [mother] and 9.57 ± 0.89 [child] years) provided 3,135 paired days of accelerometry data from six bi-annual waves across three years. Controlling for covariates, multilevel models revealed that mothers' and their children's MVPA and SDT were positively associated at the day level during non-school time, both on weekdays and weekends. During weekdays, the day-level association for SDT was stronger for older than younger children, and the day-level association for MVPA was stronger for boys than girls. Designing family-based interventions targeting school-age children and their mothers during non-school time across the week may be useful for promoting active lifestyles.

How acute affect dynamics impact longitudinal changes in physical activity among children.

Research examined how acute affect dynamics, including stability and context-dependency, contribute to changes in children's physical activity levels as they transition from late-childhood to early-adolescence. Children (N = 151) (ages 8-12 years at baseline) participated in an ecological momentary assessment and accelerometry study with six semi-annual bursts (7 days each) across three years. A two-stage mixed-effects multiple location-scale model tested random intercept, variance, and slope estimates for positive affect as predictors of moderate-to-vigorous physical activity (MVPA). Multi-year declines in MVPA were greater for children who had greater subject-level variance in positive affect. Children who experienced more positive affect when alone did not experience steeper declines in physical activity. Interventions aiming for long-term modifications in children's physical activity may focus on buffering the effects of within-day fluctuations in affect or tailoring programs to fit the needs of "acute dynamic process phenotypes."

Momentary intentions and perceived behavioral control are within-person predictors of sedentary leisure time: preliminary findings from an ecological momentary assessment study in adolescents.

Previous studies among adolescents conceptualize behavioral cognitions [e.g., intentions and perceived behavioral control (PBC)] as stable trait-like factors despite evidence suggesting they vary momentarily. We examined whether intentions and PBC momentarily relate to subsequent sedentary time during non-school periods. Healthy adolescents (N = 15, ages 11-15) reported their intentions and PBC regarding sedentary leisure behaviors via ecological momentary assessment (EMA) up to seven times/day for 14 days. Sedentary time in the two hours following each EMA prompt was measured by ActivPAL accelerometers. When participants reported greater sedentary intentions (within-person ß = 1.1, 95% CI 0.2, 2.1, p = 0.0213) and sedentary PBC (within-person ß = 1.7, 95% CI 0.6, 2.8, p = 0.0029), they accumulated greater sedentary time. This demonstrates that sedentary intentions and PBC are acutely associated with sedentary time among adolescents. Our findings highlight the potential for implementing just-in-time activity interventions among adolescents during at-risk periods within the day, characterized by deviations from one's usual intentions and PBC levels.

A chocolate cake or a chocolate vape? Young adults describe their relationship with food and weight in the context of nicotine vaping.

INTRODUCTION: Emerging research has found that some young adults report vaping nicotine to control appetite and lose weight. Yet, there is little research on how young adults use vaping to manage weight, where they learn about weight-motivated vaping, and the role that food and weight motivations play in decisions to vape. METHODS: We conducted one-on-one qualitative interviews with young adults aged 18-25 years old in Los Angeles, California (N = 62) from June 2018 to June 2019, who self-reported using e-cigarettes on a weekly basis or more for at least 5 months prior to study enrollment. Interviews examined participants' thoughts, feelings, and experiences related to e-cigarette use, including their understanding of the relation of vaping with eating behaviors and weight management. We analyzed the interviews using the rigorous and accelerated data reduction (RADaR) technique. RESULTS: Participants reported pairing nicotine vaping with caffeinated beverages like coffee, pop/soda, tea, and after every meal (like patterns of combustible cigarette use). Participants also reported vaping nicotine as a tool to avoid binge eating and increase concentration while studying. Reports of vaping effecting appetite and eating behaviors also emerged. Vaping nicotine to suppress appetite and/or achieve weight loss was often reported in conjunction with an eating disorder. Participants reported learning about weight-motivated vaping from peers or deducing from cigarette effects and their own experiences with nicotine. Others mentioned controlling food cravings by vaping a similar e-liquid flavor. CONCLUSION: Nicotine vaping was used as a tool to control weight and suppress appetite, paralleling food- and weight-related behaviors associated with cigarette use. Findings suggest a need for targeted interventions that address the role of nicotine vaping in eating/weight-related behaviors.