OBJECTIVE:To examine the effect of a brief behavioral intervention aimed at optimizing sleep duration in children on their overall health-related quality of life (HRQoL), and within physical and psychosocial health domains. METHODS:Participants were 66 typically developing children (68.2% female), aged 8-11 years, identified as short sleepers (≤9.5 h/night), randomized to a sleep intervention (n = 33) or control (n = 33) group, and who reported on HRQoL. The intervention group was provided with behavioral strategies to increase their time in bed by approximately 1-1.5 h/night; those randomized to the control group were asked to sleep as usual. Pediatric Quality of Life Inventory was administered to both parents and children to assess HRQoL at baseline and 8 weeks post-randomization. Sleep duration was objectively measured using a wrist-worn actigraph. RESULTS:At baseline, participants had a mean actigraph-estimated sleep period of 8.56 ± .67 h/night, a parent proxy-report of overall HRQoL of 82.44 ± 12.70, and a child self-report of 78.96 ± 10.88. Repeated-measures ANOVAs revealed no significant differences in overall HRQoL, physical health, or psychosocial health over time between groups (ps > .05). However, in post-hoc analyses collapsing across groups, children who increased their sleep by ≥ 30 min/night reported higher overall HRQoL (t (57) = 2.82, p = .01), psychosocial health (t (57) = 2.82, p = .01), and physical health (t (57) = 2.28, p = .03) at 8 weeks. No significant differences were observed based on parent report (ps > .05). CONCLUSION:Improving sleep by ≥ 30 min/night for children who are short sleepers may enhance their HRQoL. However, further research is necessary.

Despite improvements in pain and function following total knee replacement (TKR), most patients do not achieve recommended levels of moderate-vigorous physical activity (MVPA), putting them at increased risk of chronic disease and mortality. Thus, there is a need for effective and scalable physical activity programs for adults with TKR. This trial aims to identify which supplemental, non-automated intervention components, when added to a fully-automated online physical activity program, contribute to the greatest increases in physical activity at 6 and 12 months. This study is a randomized trial with a factorial design using the multiphase optimization strategy (MOST) framework. Adults (N = 336) who underwent a TKR at least 12 months ago receive a fully-automated, 6-month online exercise program (Energize! ) and are randomized to receive between 0 and 4 non-automated supplemental intervention components (phone calls, progress reports to healthcare providers, videos highlighting stories from others with TKR, and/or individualized human feedback sent via email). Remote assessments occur at baseline, 3 months (mid-intervention), 6 months (post-intervention), and 12 months (following a 6-month no intervention period). The primary outcome is change in accelerometer-assessed MVPA (total minutes and percentage of participants meeting the MVPA guideline of ≥ 150 min/week. Secondary outcomes include change in pain intensity and physical function. Additionally, cost-effectiveness and intervention engagement will be evaluated. This protocol paper describes a robust and innovative approach to determine the most effective intervention components to increase MVPA after TKR. Based on study findings, an optimized, remotely delivered physical activity program will be developed for this population. ClinicalTrials.gov, ID: NCT06768762. Registered on 2025-01-06.

BACKGROUND:Children consume more added sugar than recommended, with snacks a major source. OBJECTIVES:To determine the effects of repeated exposure to lower-sugar snacks, combined with caregiver education, on children's added sugar intake, acceptance of lower-sweetness foods, and sweet preferences. METHODS:In a 4-month randomized trial with 1-month follow-up, 70 preschooler-caregiver dyads were assigned to a control group receiving daily snacks typical for children and general health lessons for caregivers or an intervention group receiving lower-sugar, lower-sweetness snacks and caregiver lessons on nutrition and dental health, including guidance to limit sugary foods and remove sugar-sweetened beverages (SSBs) from the home. Primary outcomes were changes in children's added sugar and SSB intakes, acceptance of low-sweetness snacks, and taste preferences. RESULTS:At 4 months, intervention children ingested less added sugar [-10.1 tsp/d; 95% confidence interval) CI: -14.0, -6.2; P < 0.001] and SSB (-103.3 kcal/d; 95% CI: -159.2, -47.5; P < 0.001) than controls; decreases were evident by mid-trial. The intervention did not alter their liking or intake of 4 selected lower-sugar snacks or shift their most preferred sucrose concentration. However, there was significant group × time interaction for salt preferences (P = 0.045); intervention children most preferred higher salt concentrations (0.52 ± 0.04 Molarity [M]) than did controls (0.32 ± 0.04 M; P = 0.002). By mid-trial, intervention caregivers also consumed less added sugar (-17.6 tsp/d; 95% CI: -24.5, -10.7; P < 0.001) and SSBs (-255 kcal/d; 95% CI: -329, -122; P = 0.01) than controls. CONCLUSIONS:Providing lower-sugar snacks daily and caregiver education for 4 months effectively reduced daily added sugar and SSB intakes among children and their caregivers without shifting the most preferred level of sweetness. Although sodium intake was unchanged, increased salt preference among intervention children suggests a potential trade-off between added sugar and sodium content of children's snacks that warrants further investigation. "Snacks, Smiles and Taste Preferences," https://clinicaltrials.gov/study/NCT03631992?cond=sweet%20biomarkers&checkSpell=&rank=2; registration date: 08/13/2018).

Background Even with evidence-based treatment, most people who try to quit smoking return to regular smoking within weeks. Mediation analyses simultaneously test hypotheses about how treatments affect possible smoking determinants and how these determinants may influence smoking risk. Such evidence may inform treatment enhancement. Objectives Conduct secondary analyses that assess the extent to which: a) active vs. placebo nicotine patch used in conjunction with varenicline and counseling affect candidate mediators in the peri-cession period, b) candidate mediators predict next-day smoking, and c) treatment effects on next-day smoking are mediated via candidate mediators. Methods Time-varying mediation models (TVMM) were fit to ecological momentary assessment data collected nightly from 1,202 adults motivated to quit smoking in the 2 weeks preceding and 2 weeks following the target date to quit smoking in a placebo-controlled, double-blinded randomized controlled trial of adjuvant nicotine patch therapy used with varenicline and individual counseling. Results Analyses confirmed the predictive value of hypothesized mediators (cravings to smoke, nicotine withdrawal symptoms, reduced positive affect, and low quitting confidence) on next-day smoking risk, but also found that only positive affect mediated active (vs. placebo) patch effects on next-day abstinence 3-9 days after a target quit day. Discussion Adding nicotine patches to varenicline and counseling improves positive affect in ways that predict lower next-day smoking risk in the first days of attempts to quit smoking but does not significantly improve withdrawal management or sustain confidence in quitting.

Hospital readmissions following coronary artery bypass grafting (CABG) not only impose a substantial cost burden on healthcare systems but also serve as a potential indicator of the quality of medical care. Previous studies of gender effects on complications after CABG surgery have consistently revealed that women tend to suffer worse outcomes. To better understand the causal pathway from gender to the number of rehospitalizations, we study the postoperative central venous pressure (CVP), recorded over the first 24 hours of patients' intensive care unit (ICU) stay after the CABG surgery, as sparse observations of a functional mediator. Confronted with time-varying CVP measurements and zero-inflated rehospitalization counts within 60 days following discharge, we propose a parameter-simulating quasi-Bayesian Monte Carlo approximation method that accommodates a sparse functional mediator and a zero-inflated count outcome for causal mediation analysis. Focusing on patients who would undergo CABG under either gender, we find a causal relationship between the female gender and increased rehospitalization counts after CABG, and that time-varying central venous pressure mediates this causal effect.

Behavioral processes are often complex, and vary over time, requiring intensive longitudinal data to effectively capture the dynamic elements involved. For example, examining daily socio-behavioral and treatment adherence data collected during a smoking quit attempt, can reveal how, when, and why withdrawal symptoms change, offering insight into critical windows of relapse-risk in the cessation process. However, analytical methods (e.g., time-varying causal mediation methods), that can translate such intensive longitudinal data into time-varying causal effects remain limited, hindering a deeper understanding of these dynamic behavioral processes. We propose a new approach, augmented mediational g-formula with a two-step estimation strategy, to estimate time-varying causal (in)direct effects. Its performance was evaluated via simulation, comparing bias, precision, and alignment with the product-of-coefficients approach. The optimal approach identified by the simulation study was applied to data from the Wisconsin Smokers' Health Study II, for assessing the effect of randomized pharmacological treatment assignment (exposure) on daily smoking cessation outcome(s), mediated via daily treatment adherence, in the presence of a time-varying confounder (daily stress). Daily stress was due to social contextual factors but not affected by the exposure. Within its scope, this study serves as a preliminary framework for studying the causal structure of time-varying bio-behavioral processes.

BACKGROUND:Carbon (δ13C) and nitrogen (δ15N) stable isotope ratios in tissues are proposed biomarkers for dietary intake, with δ13C values reflecting added sugar intake derived from corn and sugarcane, and δ15N values reflecting animal protein intake. Research in young children is limited. OBJECTIVE:We examined associations between hair δ13C and δ15N values and dietary intake among children and also their mothers, to confirm associations found in other adults. METHODS:Hair samples and 24-h dietary recalls were collected from children (aged 5.6 ± 0.2 y; n = 138) and adults (34.1 ± 0.7 y; n = 114) in a cross-sectional study in Philadelphia. Hair δ13C and δ15N values were determined by continuous-flow isotope ratio mass spectrometry. Intake assessments focused on foods with high δ13C values [e.g. sugar-sweetened beverages (SSB)], high δ15N values (e.g. meat), or both (e.g. cow's milk). Three analytical approaches-single- (δ13C), dual- (δ13C, δ15N) isotope regression models and, uniquely, k-means cluster analysis-were used to assess associations. RESULTS:Among adults, regression models revealed positive associations of δ13C values with added sugar [β (95% confidence interval): single, 0.17 (-0.01, 0.36); dual, 0.31 (0.10, 0.53)] and SSB [single, 0.30 (0.12, 0.48); dual, 0.31 (0.09, 0.53)] intakes, confirming prior findings. Adults in the high δ13C-δ15N cluster drank more SSB than the low cluster (213 ± 23 compared with 109 ± 20 kcal/d, P = 0.03). Among children, no such associations were found. However, children in the high δ13C-δ15N cluster consumed more cow's milk (81 ± 9 compared with 31 ± 7 kcal/d, P = 0.009) and animal proteins (408 ± 33 compared with 272 ± 36 kcal/d, P = 0.04). Their cow's milk intake is significantly associated with δ13C and δ15N values. CONCLUSIONS:Age-related dietary patterns, particularly higher cow's milk consumption in children, may mask δ13C-added sugar associations, highlighting the importance of accounting for age and dietary complexity in biomarker research. This study was registered at: Snacks, Smiles and Taste Preferences as registration number NCT03631992. Website: https://clinicaltrials.gov/study/NCT03631992; Added Sugar Intake, Sweet Taste Phenotypes and Biomarkers (SWBIO), NCT05047588. Website: https://clinicaltrials.gov/ct2/show/NCT05047588.

OBJECTIVE:To assess the relationship between sensor-derived features and upper extremity function in individuals with acute and chronic cervical spinal cord injury (cSCI) and to assess the reproducibility of these features in chronic cSCI. DESIGN:Prospective, longitudinal study. Participants completed the Capabilities of Upper Extremity Test (CUE-T)-a measure of upper extremity function-at 2 time points, 4 weeks apart, while wearing a wrist-worn inertial measurement unit device on their most-used upper extremity. The device recorded 3-axis accelerometer and gyroscope data from which metrics (features) were derived. Distance correlations (dCorr) assessed associations between features and CUE-T hand and arm function scores. Intraclass correlation coefficients (ICCs) assessed the reproducibility of CUE-T scores and features in the chronic subgroup. SETTING:Inpatient rehabilitation facility (acute cSCI) and community (chronic cSCI). PARTICIPANTS:Forty adults (N=40) with cSCI were enrolled, and 33 provided data. INTERVENTIONS:Not applicable. MAIN OUTCOME MEASURES:Correlations between CUE-T scores and features; ICCs of CUE-T scores and features (chronic group). RESULTS:At Time 1, 2 features showed strong correlations with CUE-T hand score (dCorr, 0.53-0.58), while 9 showed strong correlations with CUE-T arm score (dCorr, 0.54-0.62). At Time 2, 3 features showed strong correlations with CUE-T hand score (dCorr, 0.53-0.57), while 29 showed strong correlations with CUE-T arm score (dCorr, 0.50-0.72). Types of features were distinct for hand and arm conditions. For the chronic subgroup, CUE-T scores showed excellent reproducibility (ICC, 0.94-0.99), and 16 features demonstrated moderate to good reproducibility (ICC, 0.50-0.77). CONCLUSIONS:Sensor-derived features can indicate upper extremity function in cSCI, supporting their use for monitoring recovery and functional outcomes. Future research should focus on validating features of upper extremity function to support digital biomarker development and clinical adoption.

Whether the effect of a brief behavioral sleep intervention on child weight status resulted from observed differences in sleep duration and/or bedtimes was assessed. Findings demonstrate that the intervention’s beneficial effect on weight regulation was due to earlier bedtimes, suggesting the potential importance of earlier bedtimes for obesity prevention.

OBJECTIVE:E-cigarette use is associated with subsequent cigarette smoking among youth. The current study examined the mediating role of social-cognitive factors in this association. METHODS:Data from four waves of the Population Assessment of Tobacco and Health study (2013/4 - 2017/8) were analyzed. Among youth who had heard about e-cigarettes at Wave 1 but never used cigarettes before Wave 2, we conducted both causal and traditional mediation analyses to examine the mediated effect of social-cognitive factors (including relative harm perception of e-cigarettes versus cigarettes, harm perception of e-cigarette use, perceptions of addictiveness of e-cigarette use, and e-cigarette use among best friends) in the association between e-cigarette use and subsequent cigarette ever or current smoking, adjusting for covariates. We included sampling weights in all analyses; hence, results are generalizable to the U.S. youth (12 - 14 years) from the 2013-2014 cohort. RESULTS:Results from causal mediation analyses indicated that the total effect of e-cigarette use, compared to no use, increased the risk of cigarette ever smoking (20.9 %) and current smoking (4.6 %). A portion of this effect (4.2 % - 15.1 % for ever smoking; less than 10.6 % for current smoking) can be attributed to changes in social-cognitive factors induced by e-cigarette use. However, these mediated effects were small in magnitude relative to their standard errors and not statistically significant. Results from the traditional mediation analyses largely aligned with these findings, except for a few small sized pathways. CONCLUSIONS:For the U.S. youth population, social-cognitive factors may only minimally or not at all mediate the association between e-cigarette use and subsequent cigarette smoking. Further investigation into the mediation role of social-cognitive factors is warranted. Tobacco control interventions that focus on cigarette smoking initiation among youth should target other mediating factors.

OBJECTIVE:To determine the associations between trauma variables, acute phase-related variables, and patient-level characteristics with functional recovery during inpatient rehabilitation for individuals with spinal cord injury (SCI). The associations were evaluated by linking individuals' records between the Pennsylvania Trauma Systems Outcomes Study and the National SCI Model Systems databases. DESIGN:Retrospective cohort analysis. SETTING:Two SCI Model Centers in Pennsylvania, United States. METHODS:We used a record linkage toolkit in Python to link 735 individuals with traumatic SCI between the databases. The percentage for true-match and error were 92.0% and 0.1%, respectively. The functional recovery during inpatient rehabilitation was determined in 604 individuals with SCI by ordinary least squares regression (OLS) and gradient boosting regression (GBR) analyses. RESULTS:The OLS and GBR analyses indicated older age, greater impairment (SCI level combined with American Spinal Injury Association impairment scale), presence of diabetes mellitus, pulmonary complications during acute care, and longer length of stay at an inpatient rehabilitation facility were associated with lower functional recovery (OLS R2 = 0.56 and GBR R2 = 0.58). CONCLUSIONS:Trauma and acute care variables in addition to patient characteristics were associated with functional recovery during inpatient rehabilitation in individuals with SCI. Further investigation is needed to understand the role of diabetes mellitus and pulmonary complications, which have not been previously associated with functional recovery in individuals with SCI.

Background The lack of regular physical activity (PA) in individuals with spinal cord injury (SCI) in the United States is an ongoing health crisis. Regular PA and exercise-based interventions have been linked with improved outcomes and healthier lifestyles among those with SCI. Providing people with an accurate estimate of their everyday PA level can promote PA. Furthermore, PA tracking can be combined with mobile health technology such as smartphones and smartwatches to provide a just-in-time adaptive intervention (JITAI) for individuals with SCI as they go about everyday life. A JITAI can prompt an individual to set a PA goal or provide feedback about their PA levels. Objective The primary aim of this study is to investigate whether minutes of moderate-intensity PA among individuals with SCI can be increased by integrating a JITAI with a web-based PA intervention (WI) program. The WI program is a 14-week web-based PA program widely recommended for individuals with disabilities. A secondary aim is to investigate the benefit of a JITAI on proximal PA, defined as minutes of moderate-intensity PA within 120 minutes of a PA feedback prompt. Methods Individuals with SCI (N=196) will be randomized to a WI arm or a WI+JITAI arm. Within the WI+JITAI arm, a microrandomized trial will be used to randomize participants several times a day to different tailored feedback and PA recommendations. Participants will take part in the 24-week study from their home environment in the community. The study has three phases: (1) baseline, (2) WI program with or without JITAI, and (3) PA sustainability. Participants will provide survey-based information at the initial meeting and at the end of weeks 2, 8, 16, and 24. Participants will be asked to wear a smartwatch every day for ≥12 hours for the duration of the study. Results Recruitment and enrollment began in May 2023. Data analysis is expected to be completed within 6 months of finishing participant data collection. Conclusions The JITAI has the potential to achieve long-term PA performance by delivering tailored, just-in-time feedback based on the person’s actual PA behavior rather than a generic PA recommendation. New insights from this study may guide intervention designers to develop engaging PA interventions for individuals with disability. Trial Registration ClinicalTrials.gov NCT05317832; https://clinicaltrials.gov/study/NCT05317832 International Registered Report Identifier (IRRID) DERR1-10.2196/57699

BackgroundChronic pain affects 70% of individuals with spinal cord injury (SCI) and leads to declines in health and quality of life. Neuropathic and nociceptive pain are phenotypes derived from different mechanisms that contribute to pain perception. The objective of this research was to investigate differential pain responses to moderate-to-vigorous physical activity (MVPA) in two chronic pain phenotypes: neuropathic and nociceptive pain.MethodsCommunity-based physical activity levels were collected for one week in 17 individuals with SCI using a wrist-worn accelerometer, and daily pain ratings were assessed and categorized by phenotype. Physical activity levels were summarized to calculate minutes of MVPA. Correlational analyses were conducted to compare relationships between pain intensity and MVPA across individual participants and between pain phenotype groups.ResultsThe neuropathic pain group revealed significant negative correlation between MVPA and pain intensity. In the nociceptive pain group, there was no significant correlation between MVPA and pain intensity. Further analysis revealed two subgroups of positive (N = 4) and negative (N = 3) correlations between MVPA and pain intensity. Pain location differed between the subgroups of nociceptive pain. Individuals with negative correlation experienced neck and upper back pain, whereas individuals with positive correlation experienced unilateral upper extremity pain.ConclusionDifferential relationships exist between pain phenotypes and MVPA in individuals with SCI. Pain location differed between the subgroups of nociceptive pain, which we presume may indicate the presence of nociplastic pain in some individuals. These results may contribute to the advancement of personalized pain management by targeting non-pharmacological interventions for specific pain phenotypes.Trial registration: ClinicalTrials.gov identifier: NCT05236933..ConclusionDifferential relationships exist between pain phenotypes and MVPA in individuals with SCI. Pain location differed between the subgroups of nociceptive pain, which we presume may indicate the presence of nociplastic pain in some individuals. These results may contribute to the advancement of personalized pain management by targeting non-pharmacological interventions for specific pain phenotypes.Trial registration: ClinicalTrials.gov identifier: NCT05236933..

Background: Recreating in waterbodies impacted by combined sewer overflows (CSOs) can present health risks due to exposure to microbial pathogens. This study compares population characteristics of those living within walking distance to CSO-impacted versus nonimpacted waters in Philadelphia to determine whether these populations differ by race, ethnicity, and sociodemographic characteristics.Methods: Adults recreating at or near natural water bodies in Philadelphia completed a questionnaire that assessed the average walking distance to each site. Walking distance boundaries informed by questionnaire responses were created around each waterbody in Philadelphia, and population-level census data corresponding with block groups included within each buffer were used to characterize those living near a CSO-impacted and nonimpacted waterbodies in Philadelphia.Results: Compared with populations residing in census block groups within walking distance to a nonimpacted waterway, populations living within the same distance to a CSO-impacted waterway were more likely to comprise Hispanic residents (standardized adjusted prevalence ratio [APR] = 1.13) and those living in poverty (APR = 1.21) and less likely to comprise White residents (APR = 0.76).Conclusion: These findings suggest that communities of color and those experiencing poverty are disproportionally impacted by environmental hazards.

Background Causal mediation analysis plays a crucial role in examining causal effects and causal mechanisms. Yet, limited work has taken into consideration the use of sampling weights in causal mediation analysis. In this study, we compared different strategies of incorporating sampling weights into causal mediation analysis.Methods We conducted a simulation study to assess 4 different sampling weighting strategies-1) not using sampling weights, 2) incorporating sampling weights into mediation "cross-world" weights, 3) using sampling weights when estimating the outcome model, and 4) using sampling weights in both stages. We generated 8 simulated population scenarios comprising an exposure (A), an outcome (Y), a mediator (M), and six covariates (C), all of which were binary. The data were generated so that the true model of A given C and the true model of A given M and C were both logit models. We crossed these 8 population scenarios with 4 different sampling methods to obtain 32 total simulation conditions. For each simulation condition, we assessed the performance of 4 sampling weighting strategies when calculating sample-based estimates of the total, direct, and indirect effects. We also applied the four sampling weighting strategies to a case study using data from the National Survey on Drug Use and Health (NSDUH).Results Using sampling weights in both stages (mediation weight estimation and outcome models) had the lowest bias under most simulation conditions examined. Using sampling weights in only one stage led to greater bias for multiple simulation conditions.Discussion Using sampling weights in both stages is an effective approach to reduce bias in causal mediation analyses under a variety of conditions regarding the structure of the population data and sampling methods.

Mediation analysis is a statistical approach that can provide insights regarding the intermediary processes by which an intervention or exposure affects a given outcome. Mediation analyses rose to prominence, particularly in social science research, with the publication of Baron and Kenny’s seminal paper and is now commonly applied in many research disciplines, including health services research. Despite the growth in popularity, applied researchers may still encounter challenges in terms of conducting mediation analyses in practice. In this paper, we provide an overview of conceptual and methodological challenges that researchers face when conducting mediation analyses. Specifically, we discuss the following key challenges: (1) Conceptually differentiating mediators from other “third variables,” (2) Extending beyond the single mediator context, (3) Identifying appropriate datasets in which measurement and temporal ordering support the hypothesized mediation model, (4) Selecting mediation effects that reflect the scientific question of interest, (5) Assessing the validity of underlying assumptions of no omitted confounders, (6) Addressing measurement error regarding the mediator, and (7) Clearly reporting results from mediation analyses. We discuss each challenge and highlight ways in which the applied researcher can approach these challenges.