Clinical Significance of Pheochromocytoma Size on the Timing and Extent of Surgery.

INTRODUCTION: Elevated metanephrine and catecholamine levels 3-fold upper limit of normal (ULN) are diagnostic for pheochromocytoma. We sought to determine whether size correlates with biochemical activity or symptoms which could guide timing of surgery. METHODS: Data from consecutive patients undergoing adrenalectomy for pheochromocytoma at our institution over a 10-year period were retrospectively collected. These included maximal lesion diameter on preoperative imaging, plasma/urine metanephrine and/or catecholamine levels, demographic variables and presence of typical paroxysmal symptoms. Receiver operating characteristic curves were used to assess predictive accuracy. RESULTS: Sixty-three patients were included in the analysis (41 females and 22 males). Median age was 56 (43, 69) years. Due to various referring practices, 31 patients had documented 24-h urine metanephrine, 26 had 24-h urine catecholamine, and 52 had fractionated plasma metanephrine levels available for review. Values were converted to fold change compared to ULN and the maximum of all measured values was used for logistic regression. Median tumor size was 3.40 (2.25, 4.55) cm in greatest dimension. Tumor size at which pheochromocytoma produced > 3-fold ULN was ≥2.3 cm (AUC of 0.84). Biochemical activity increased with doubling tumor size (odds ratio = 8, P = 0.0004) or ≥ 1 cm increase in tumor size (odds ratio = 3.03, P = 0.001). 40 patients had paroxysmal symptoms, but there was no significant correlation between tumor size/biochemical activity and symptoms. CONCLUSIONS: In our study, tumor size directly correlated with the degree of biochemical activity and pheochromocytomas ≥2.3 cm produced levels 3 times ULN. These findings may allow clinicians to adjust timing of operative intervention.

A Social Media Quality Review of Popular Sinusitis Videos on TikTok.

OBJECTIVE: Social media may inform health care decisions among younger patient populations. TikTok is a social media platform that allows users to post short-form videos. This study aimed to assess the quality of sinusitis-related videos on TikTok. STUDY DESIGN: We searched TikTok on January 29, 2023, for sinusitis-related hashtags: #sinusitis, #sinus, #sinusinfection. SETTING: Internet. METHODS: The number of views/shares per day, uploader type (nonmedical influencer, lay individual, and medical professional) content categories (medical advice, marketing, comedy, and lifestyle/acceptability), and content type (educational vs factual) were collected. The Patient Education Materials Assessment Tool for Audiovisual Material and Journal of the American Medical Association criteria score was used to measure understandability, actionability, and reliability. The Global Quality Scale (GQS) was used to evaluate the quality of videos; the harm/benefit score was used to evaluate causative effects. Analyses were performed using analysis of variance (α = .05). RESULTS: There were 221 videos identified, which garnered over 300 million views and 1 million shares. Almost half of the videos were published by nonmedical influencers. When controlling for covariates, nonmedical influencers and lay uploaders were more likely to have harmful harm/benefit scores, less understandable videos, and lower GQS scores compared to medical professionals. Less than half of videos posted by nonmedical influencers categorized as educational were factual (46.7%); lay individuals and medical professionals had higher rates of factual educational content (79.9% and 83.7%, respectively). CONCLUSION: Most nonmedical influencer-posted TikTok videos about sinusitis are inaccurate, despite being portrayed as medical advice/educational. Rhinologists must find modern ways to disseminate true disease-related content via social media to combat medical misinformation.

Socioeconomic status is associated with pediatric adenotonsillectomy outcomes: A single institution study.

OBJECTIVE: Our institution serves a diverse patient population across a large metropolitan city. Literature has shown pediatric otolaryngology patients with lower socioeconomic status (SES) have higher rates of sleep-disordered breathing, delays in treatment time, and greater risks of complications post-tonsillectomy. This study aims to examine the effects of SES on adenotonsillectomy outcomes performed at our institution. STUDY DESIGN: A retrospective chart review including 1560 pediatric patients (ages 0-18) who underwent adenotonsillectomy between January 2015 and December 2020. SETTING: Large metropolitan hospital, level 1 trauma center. METHODS: Outcome variables included postoperative hospital admission, phone calls, 30-day follow-up, and persistent obstructive sleep apnea (OSA). Descriptive statistics using Wilcoxon Signed Rank Tests and univariate and multivariate logistic regression modeling were used to determine statistically significant covariates at α = 0.05. RESULTS: The cohort included Non-Hispanic White (n = 488, 31 %), Non-Hispanic Black (n = 801, 51 %), Hispanic (n = 210, 13 %), and other (n = 61, 4 %) groups. Using multivariate regression, privately insured patients were less likely to have moderate-to-severe OSA before surgery (0.65 95 % CI 0.45, 0.93 p = 0.017) and be admitted postoperatively (0.73, 0.55-0.96, p < 0.01), while more likely to have postoperative follow-up phone calls (1.57, 1.19-2.09, p < 0.01) and visits (1.53, 1.22-1.92, p < 0.01). Increased income was associated with decreased rehospitalizations within three months of surgery (0.98, 0.97-1.00, p < 0.01). CONCLUSION: This study suggests SES significantly affects adenotonsillectomy outcomes. Further studies are warranted to provide better care for all pediatric patients.

Single center outcomes from parenchymal-sparing resections and microwave ablations for neuroendocrine tumor liver metastases.

BACKGROUND: Reported outcomes after surgical debulking in patients with advanced neuroendocrine tumor liver metastases (NETLM) are sparse. METHODS: NETLM patients that underwent surgical debulking from 2019 to 2021 were reviewed. Trends in perioperative liver function, complications, symptom response, and progression-free survival were examined. RESULTS: 1069 liver lesions were debulked from 53 patients using a combination of parenchymal-sparing resections (PSR) and ultrasound-guided microwave ablations (MWA). Post-operative transaminitis and thrombocytopenia were common, and severity correlated with increasing number of lesions. Laboratory markers for synthetic liver function did not differ according to the number of lesions debulked. 13% of patients sustained a Clavien-Dindo grade 3 or 4 complication which was not associated with the number of lesions targeted. All patients with preoperative symptoms had improvement after surgery. Median time to progression was 10.9 months. CONCLUSIONS: PSR with MWA for large numbers of NETLM is safe and effective for symptom control and does not affect synthetic liver function.

Factors Associated with Health-Related Quality of Life in Lung Transplant Candidates and Recipients.

OBJECTIVES: Health-related quality of life has been well studied across transplantation fields, but factors associated with lung transplant preoperative and postoperative quality of life remain unknown. Here, we determine factors associated with health-related quality of life in lung transplant candidates and recipients to identify patients at risk of lower health-related quality of life. MATERIALS AND METHODS: From January 2021 to May 2022, health-related quality of life was measured in candidates and recipients using the RAND 36-Item Short Form Health Survey questionnaire. We reviewed demographic parameters and clinical information and scored frailty according to the modified 5-item frailty index. We performed Fisher exact test and the Pearson chi-square test and used linear regression models to determine covariate associations on physical component summary, mental component summary, and self-reported health scores (α = 0.05). RESULTS: Eleven candidates and 17 recipients comp-leted the survey. Compared with candidates, transplant recipients reported significantly higher scores in 4 of the 8 health domains and in the physical component summary (P < .01), mental component summary (P = .05), and self-reported health score (P < .01). In candidates, higher body mass index and higher modified 5-item frailty index scores were negatively associated with the physical component summary and mental component summary, respec-tively (P < .05). In recipients, higher body mass index and higher lung allocation scores were associated with lower values for the physical component summary (-2.29; P < .05) and self-reported health score (-0.33; P < .05), respectively. CONCLUSIONS: Body mass index, the modified 5-item frailty index, and the lung allocation score were significantly associated with health-related quality of life in lung transplant recipients. Future interventions should target these modifiable associations to maximize candidate and recipient health-related quality of life.

Assessment of Demographic Changes of Workforce Diversity in Otolaryngology, 2013 to 2022.

Importance: Given the growth of minoritized groups in the US and the widening racial and ethnic health disparities, improving diversity remains a proposed solution in the field of otolaryngology. Evaluating current trends in workforce diversity may highlight potential areas for improvement. Objective: To understand the changes in gender, racial, and ethnic diversity in the otolaryngology workforce in comparison with changes in the general surgery and neurosurgery workforces from 2013 to 2022. Design, Setting, and Participants: This cross-sectional study used publicly available data from the Accreditation Council for Graduate Medical Education and the Association of American Medical Colleges for 2013 to 2022, and included medical students and trainees in all US medical residency programs and allopathic medical schools. Main Outcomes and Measures: Average percentages of women, Black, and Latino trainees during 2 intervals of 5 years (2013-2017 and 2018-2022). Pearson χ2 tests compared demographic information. Normalized ratios were calculated for each demographic group in medical school and residency. Piecewise linear regression assessed linear fit for representation across time periods and compared rates of change. Results: The study population comprised 59 865 medical residents (43 931 [73.4%] women; 6203 [10.4%] Black and 9731 [16.2%] Latino individuals; age was not reported). The comparison between the 2 study intervals showed that the proportions of women, Black, and Latino trainees increased in otolaryngology (2.9%, 0.7%, and 1.6%, respectively), and decreased for Black trainees in both general surgery and neurosurgery (-0.4% and -1.0%, respectively). In comparison with their proportions in medical school, Latino trainees were well represented in general surgery, neurosurgery, and otolaryngology (normalized ratios [NRs]: 1.25, 1.06, and 0.96, respectively); however, women and Black trainees remained underrepresented in general surgery, neurosurgery, and otolaryngology (women NRs, 0.76, 0.33, and 0.68; Black NRs, 0.63, 0.61, and 0.29, respectively). The percentage of women, Black, and Latino trainees in otolaryngology all increased from 2020 to 2022 (2.5%, 1.1%, and 1.1%, respectively). Piecewise regression showed positive trends across all 3 specialties. Conclusions and Relevance: The findings of this cross-sectional study indicate a positive direction but only a modest increase of diversity in otolaryngology, particularly in the context of national demographic data. Novel strategies should be pursued to supplement existing efforts to increase diversity in otolaryngology.

Histotripsy induces apoptosis and reduces hypoxia in a neuroblastoma xenograft model.

BACKGROUND: Neuroblastoma (NB) is the most common extracranial solid tumor of childhood, and high-risk disease is resistant to intensive treatment. Histotripsy is a focused ultrasound therapy under development for tissue ablation via bubble activity. The goal of this study was to assess outcomes of histotripsy ablation in a xenograft model of high-risk NB. METHODS: Female NCr nude mice received NGP-luciferase cells intrarenally. Under ultrasound image guidance, histotripsy pulses were applied over a distance of 4-6 mm within the tumors. Bioluminescence indicative of tumor viability was quantified before, immediately after, and 24 h after histotripsy exposure. Tumors were immunostained to assess apoptosis (TUNEL), endothelium (endomucin), pericytes (αSMA), hypoxia (pimonidazole), vascular endothelial growth factor A (VEGFA), and platelet-derived growth factor-B (PDGF-B). The apoptotic cytokine TNFα and its downstream effector cleaved caspase-3 (c-casp-3) were assessed with SDS-PAGE. RESULTS: Histotripsy induced a 50% reduction in bioluminescence compared to untreated controls, with an absence of nuclei in the treatment core surrounded by a dense rim of TUNEL-positive cells. Tumor regions not targeted by histotripsy also showed an increase in TUNEL staining density. Increased apoptosis in histotripsy samples was consistent with increases in TNFα and c-casp-3 relative to controls. Treated tumors exhibited a decrease in hypoxia, VEGF, PDGF-B, and pericyte coverage of vasculature compared to control samples. Further, increases in vasodilation were found in histotripsy-treated specimens. CONCLUSIONS: In addition to ablative effects, histotripsy was found to drive tumor apoptosis through intrinsic pathways, altering blood vessel architecture, and reducing hypoxia.

Embolization in Juvenile Nasopharyngeal Angiofibroma Surgery: A Systematic Review and Meta-Analysis.

OBJECTIVE: To compare outcomes of juvenile nasopharyngeal angiofibroma (JNA) resection between embolized and non-embolized cohorts, and between transarterial embolization (TAE) and direct puncture embolization (DPE). DATA SOURCES: Per PRISMA guidelines, PubMed, Embase, Web of Science, Scopus, and Cochrane databases were searched for publications prior to or in 2021. MATERIALS AND METHODS: Original English manuscripts investigating the resection of JNA with and without preoperative embolization were included. Embolization type, recurrence rate, complication rates, blood loss, and transfusions were extracted. Risk of bias was assessed by the Risk of Bias in Non-randomized Studies-of Interventions method. RESULTS: There were 61 studies with 917 patients included. Preoperative embolization was performed in 79.3% of patients. Of those embolized, 75.8% (N = 551) underwent TAE and 15.8% (N = 115) underwent DPE. JNA recurrence in embolized patients was lower than in non-embolized patients (9.3% vs. 14.4%; odds ratio [OR]: 0.61, 95% confidence interval [CI]: 0.35, 1.06). DPE resulted in lower rates of disease recurrence (0% vs. 9.5%; OR: 0.066, 95% CI: 0.016, 0.272) and complications (1.8% vs. 21.9%; OR: 0.07, 95% CI: 0.02, 0.3) than TAE. A random effects Bayesian model was performed to analyze the difference in mean blood loss in 6 studies that included both embolized and non-embolized patients. This analysis showed a mean reduction in blood loss of 798 mL in the embolized group. CONCLUSIONS: We found embolization decreases blood loss in JNA resection. DPE led to improved recurrence and complication rates when compared to TAE, but future prospective studies are needed to further evaluate which embolization technique can optimize outcomes in JNA. LEVEL OF EVIDENCE: NA Laryngoscope, 133:1529-1539, 2023.

Community health worker intervention to improve tooth brushing in young children: Results from a cluster randomized controlled trial.

OBJECTIVES: Coordinated Oral health Promotion (CO-OP) Chicago is a cluster randomized controlled trial testing the efficacy of a community health worker (CHW) intervention to improve tooth brushing in low-income children. METHODS: Four hundred twenty children under 3 years old (mean 21.5 months) were recruited from 20 sites in or near Chicago, IL. Children were identified mainly as Black race (41.9%) or Hispanic ethnicity (53.8%) and most (85.2%) had Medicaid. Intervention families were offered four CHW home visits over 1 year. Brushing frequency was self-reported. Plaque score was determined from images collected in homes using disclosing solution. Analyses used GEE logistic models with variable selection at p < .05. RESULTS: At enrolment, 45.0% of families reported twice a day or more child brushing frequency, and child plaque scores were poor (mean of 1.9, SD: 0.6). Data were obtained from 87.1% of children at 6 months and 86.2% at 12 months. In the CHW intervention arm (10 sites, N = 211), 23.7% received 4 visits, 12.8% 3 visits, 21.3% 2 visits, 23.2% 1 visit and 19% no visits from CHWs. No intervention effect was seen for brushing frequency or plaque score. Child brushing frequency improvement over time was associated with a range of child and caregiver factors. The only factor associated with a change in plaque score over time was parent involvement in brushing. CONCLUSIONS: Oral-health-specific CHW services were not associated with improved brushing behaviours in these young children. However, caregiver involvement with brushing supported more quality brushing. More robust interventions are needed to support families during this critical developmental period.

Racial differences in phenotypic frailty assessment among general thoracic surgery patients.

Objectives: The American Association for Thoracic Surgery recommends using frailty assessments to identify patients at higher risk of perioperative morbidity and mortality. We evaluated what patient factors are associated with frailty in a thoracic surgery patient population. Methods: New patients aged more than 50 years who were evaluated in a thoracic surgery clinic underwent routine frailty screening with a modified Fried's Frailty Phenotype. Differences in demographics and comorbid conditions among frailty status groups were assessed with chi-square and Student t tests. Logistic regressions performed with binomial distribution assessed the association of demographic and clinical characteristics with nonfrail, frail, prefrail, and any frailty (prefrail/frail) status. Results: The study population included 317 patients screened over 19 months. Of patients screened, 198 (62.5%) were frail or prefrail. Frail patients undergoing thoracic surgery were older, were more likely single or never married, had lower median income, and had lower percent predicted diffusion capacity of the lungs for carbon monoxide and forced expiratory volume during 1 second (all P < .05). More non-Hispanic Black patients were frail and prefrail compared with non-Hispanic White patients (P = .003) and were more likely to score at least 1 point on Fried's Frailty Phenotype (adjusted odds ratio, 3.77; P = .02) when controlling for age, sex, number of comorbidities, median income, diffusion capacity of the lungs for carbon monoxide, and forced expiratory volume during 1 second. Non-Hispanic Black patients were more likely than non-Hispanic White patients to score points for slow gait and low activity (both P < .05). Conclusions: Non-Hispanic Black patients undergoing thoracic surgery are more likely to score as frail or prefrail than non-Hispanic White patients. This disparity stems from differences in activity and gait speed. Frailty tools should be examined for factors contributing to this disparity, including bias.

Oral community health worker-led interventions in households with average levels of psychosocial factors.

Introduction: Household-level psychosocial stress levels have been linked to child tooth brushing behaviors. Community health worker (CHW) interventions that target psychosocial factors in high-risk communities have been associated with changes in health behaviors. Aim: Observe changes in psychosocial factors over time and an association between psychosocial factors and CHW intervention dose amongst urban Chicago families. Patients and methods: Participants (N = 420 families) were recruited from 10 community clinics and 10 Women, Infants, or Children (WIC) centers in Cook County, Illinois to participate in a clinical trial. Research staff collected participant-reported psychosocial factors (family functioning and caregiver reports of depression, anxiety, support, and social functioning) and characteristics of CHW-led oral health intervention visits (number, content, child engagement) at 0, 6, and 12 months. CHWs recorded field observations after home visits on household environment, social circumstances, stressors, and supports. Results: Participants across the cohort reported levels of psychosocial factors consistent with average levels for the general population for nearly all measures. Psychosocial factors did not vary over time. Social functioning was the only measure reported at low levels [32.0 (6.9); 32.1 (6.7); 32.7 (6.9); mean = 50 (standard deviation)] at 0, 6, and 12 months. We did not observe a meaningful difference in social functioning scores over time by exposure to CHW-led intervention visits (control arm, 0, 1, 2, 3, and 4 visits). Field observations made by CHWs described a range of psychosocial stress related to poverty, language barriers, and immigration status. Conclusion: The unexpectedly average and unchanging psychosocial factors over time, in the context of field observations of stress related to poverty, lack of support, immigration status, and language barriers, suggests that our study did not adequately capture the social determinants of health related to oral health behaviors or that measurement biases precluded accurate assessment. Future studies will assess psychosocial factors using a variety of instruments in an attempt to better measure psychosocial factors including social support, depression, anxiety, functioning, trauma and resilience within our urban population. We will also look at neighborhood-level factors of community distress and resilience to better apply the social ecologic model to child oral health behaviors.

Schistosomiasis is associated with rectal mucosal inflammation among Kenyan men who have sex with men.

Background:Schistosoma mansoni infection is hyperendemic in Lake Victoria communities and associated with cervicovaginal immune alterations and HIV acquisition. We assessed the hypothesis that schistosomiasis correlates with greater rectal inflammation in men who have sex with men (MSM) in Kisumu, Kenya. Methods: In this cross-sectional study of 38 HIV-negative MSM aged 18-35 years, schistosomiasis was diagnosed by urine circulating cathodic antigen (CCA). Microbiome was assessed in rectal swabs by 16S rRNA gene amplicon sequencing, and rectal inflammation by quartile normalized summative score of inflammatory cytokines (IL-1α, IL-1ß, IL-8, and TNF-α). Elastic net (EN) regression identified taxa associated with inflammation. Multivariable linear regression estimated the association between inflammation score and schistosomiasis and bacteria identified in EN. Results: Most men were CCA positive (24/38; 63%), and median rectal inflammation score was significantly higher in these participants (11 vs. 8, p = 0.04). In multivariable regression, CCA-positive men had 2.85-point greater inflammation score (p = 0.009). The relative abundance of Succinivibrio (coefficient = -1.13, p = 0.002) and Pseudomonas (coefficient = -1.04, p = 0.001) were negatively associated with inflammation. Discussion: CCA positivity was associated with rectal mucosal inflammation, controlling for rectal microbiome composition. Given its high prevalence and contribution to inflammation, schistosomiasis may have important implications for HIV transmission in this vulnerable population.

An empirical example of analysis using a two-stage modeling approach: within-subject association of outdoor context and physical activity predicts future daily physical activity levels.

People differ from each other to the extent to which momentary factors, such as context, mood, and cognitions, influence momentary health behaviors. However, statistical models to date are limited in their ability to test whether the association between two momentary variables (i.e., subject-level slopes) predicts a subject-level outcome. This study demonstrates a novel two-stage statistical modeling strategy that is capable of testing whether subject-level slopes between two momentary variables predict subject-level outcomes. An empirical case study application is presented to examine whether there are differences in momentary moderate-to-vigorous physical activity (MVPA) levels between the outdoor and indoor context in adults and whether these momentary differences predict mean daily MVPA levels 6 months later. One hundred and eight adults from a multiwave longitudinal study provided 4 days of ecological momentary assessment (during baseline) and accelerometry data (both at baseline and 6 month follow-up). Multilevel data were analyzed using an open-source program (MixWILD) to test whether momentary strength between outdoor context and MVPA during baseline was associated with average daily MVPA levels measured 6 months later. During baseline, momentary MVPA levels were higher in outdoor contexts as compared to indoor contexts (b = 0.07, p < .001). Participants who had more momentary MVPA when outdoors (vs. indoors) during baseline (i.e., a greater subject-level slope) had higher daily MVPA at the 6 month follow-up (b = 0.09, p < .05). This empirical example shows that the subject-level momentary association between specific context (i.e., outdoors) and health behavior (i.e., physical activity) may contribute to overall engagement in that behavior in the future. The demonstrated two-stage modeling approach has extensive applications in behavioral medicine to analyze intensive longitudinal data collected from wearable sensors and mobile devices.

Characteristics of Women and Their Male Sex Partners Predict Bacterial Vaginosis Among a Prospective Cohort of Kenyan Women With Nonoptimal Vaginal Microbiota.

BACKGROUND: Up to 50% of women with nonoptimal vaginal microbial community state type (CST) have bacterial vaginosis (BV). Little is known about what distinguishes women with and without BV diagnosis within nonoptimal CST. We identified features of women and their male sex partners associated with BV among women with nonoptimal vaginal CST. METHODS: In this prospective study, 252 heterosexual couples were observed at 1, 6, and 12 months after baseline. Microbiomes were characterized in cervicovaginal lavage and penile meatal swabs through high-throughput 16s ribosomal RNA gene amplicon sequencing. Nonoptimal CST was defined as CST-IV. Bacterial vaginosis was defined as a Nugent score of 7 to 10. Generalized estimating equation analysis estimated adjusted odds ratios (aORs) for BV among women with nonoptimal CST. RESULTS: At baseline, women with nonoptimal CST were a median age of 22 years, 44% had BV, 16% had HIV, and 66% had herpes simplex virus (HSV) type 2. Male partners were a median age of 27 years, 12% had HIV, 48% had HSV-2, and 55% were circumcised. Within nonoptimal CST, Sneathia sanguinegens, Prevotella species, Prevotella amnii, and Clostridiales, BV-associated bacteria-2 were statistically significantly enriched in observations with BV. In multivariable generalized estimating equation controlling for CST, HIV, and HSV-2, BV was increased among women with CST-IVA (aOR, 1.91; P = 0.087), HIV (aOR, 2.30; P = 0.051), HSV-2 (aOR, 1.75; P = 0.065), and enrichment of male partner penile taxa: Dialister (aOR, 1.16; P = 0.034), Megasphaera (aOR, 1.22; P = 0.001), and Brevibacterium (aOR, 1.13; P = 0.019).These results provide insights into factors differentiating women with BV among those with nonoptimal vaginal CST. Interrupting the sexual exchange of penile and vaginal taxa may be beneficial for preventing pathologic state of vaginal microbiome.

The Story of Goldilocks and Three Twitter's APIs: A Pilot Study on Twitter Data Sources and Disclosure.

Public health and social science increasingly use Twitter for behavioral and marketing surveillance. However, few studies provide sufficient detail about Twitter data collection to allow either direct comparisons between studies or to support replication. The three primary application programming interfaces (API) of Twitter data sources are Streaming, Search, and Firehose. To date, no clear guidance exists about the advantages and limitations of each API, or about the comparability of the amount, content, and user accounts of retrieved tweets from each API. Such information is crucial to the validity, interpretation, and replicability of research findings. This study examines whether tweets collected using the same search filters over the same time period, but calling different APIs, would retrieve comparable datasets. We collected tweets about anti-smoking, e-cigarettes, and tobacco using the aforementioned APIs. The retrieved tweets largely overlapped between three APIs, but each also retrieved unique tweets, and the extent of overlap varied over time and by topic, resulting in different trends and potentially supporting diverging inferences. Researchers need to understand how different data sources can influence both the amount, content, and user accounts of data they retrieve from social media, in order to assess the implications of their choice of data source.

MixWILD: A program for examining the effects of variance and slope of time-varying variables in intensive longitudinal data.

The use of intensive sampling methods, such as ecological momentary assessment (EMA), is increasingly prominent in medical research. However, inferences from such data are often limited to the subject-specific mean of the outcome and between-subject variance (i.e., random intercept), despite the capability to examine within-subject variance (i.e., random scale) and associations between covariates and subject-specific mean (i.e., random slope). MixWILD (Mixed model analysis With Intensive Longitudinal Data) is statistical software that tests the effects of subject-level parameters (variance and slope) of time-varying variables, specifically in the context of studies using intensive sampling methods, such as ecological momentary assessment. MixWILD combines estimation of a stage 1 mixed-effects location-scale (MELS) model, including estimation of the subject-specific random effects, with a subsequent stage 2 linear or binary/ordinal logistic regression in which values sampled from each subject's random effect distributions can be used as regressors (and then the results are aggregated across replications). Computations within MixWILD were written in FORTRAN and use maximum likelihood estimation, utilizing both the expectation-maximization (EM) algorithm and a Newton-Raphson solution. The mean and variance of each individual's random effects used in the sampling are estimated using empirical Bayes equations. This manuscript details the underlying procedures and provides examples illustrating standalone usage and features of MixWILD and its GUI. MixWILD is generalizable to a variety of data collection strategies (i.e., EMA, sensors) as a robust and reproducible method to test predictors of variability in level 1 outcomes and the associations between subject-level parameters (variances and slopes) and level 2 outcomes.

Extending the mixed-effects model to consider within-subject variance for Ecological Momentary Assessment data.

Ecological Momentary Assessment data present some new modeling opportunities. Typically, there are sufficient data to explicitly model the within-subject (WS) variance, and in many applications, it is of interest to allow the WS variance to depend on covariates as well as random subject effects. We describe a model that allows multiple random effects per subject in the mean model (eg, random location intercept and slopes), as well as random scale in the error variance model. We present an example of the use of this model on a real dataset and a simulation study that shows the benefit of this model, relative to simpler approaches.

Do fluctuations in positive affective and physical feeling states predict physical activity and sedentary time?

OBJECTIVES: Higher levels of positive affect and feelings of energy and vitality 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 within-person variability in positive affect and feeling energetic predicted participants' overall levels of PA and ST. DESIGN: This analysis combined data from four ecological momentary assessment (EMA) studies (agerange: 8-73 years) with ambulatory monitoring via waist-worn accelerometry (N=661). METHODS: Positive affect and energy were assessed through EMA several times per day across 4-7 days. Accelerometer data was used to create the following behavioral outcomes: (1) meeting MVPA guidelines (children: 60 minutes/day, adults: 30 minutes/day) and (2) minutes of ST per hour of accelerometer wear. A two-stage analytic approach was used to test the study aim. In the first stage, Mixed-Effects Location Scale Modeling decomposed mean levels and variability in positive affect and energy. In the second stage, a linear or logistic regression (depending on whether the outcome was continuous or dichotomous, respectively) was tested to investigate associations between subject-level mean and variability in EMA ratings and the behavioral outcome. RESULTS: Greater subject-level variability but not subject-level mean of feeling energetic was associated with lower odds of meeting MVPA guidelines (ß=-0.43, p<0.05). CONCLUSIONS: Fluctuations in physical feeling states may deplete self-regulatory resources involved in planning and implementing PA behavior. Alternatively, being more physically active may stabilize one's perceived energy levels.