The Relationship of Structured Environments With Children’s Body Composition and Obesogenic Behaviors

Recent nationally representative data show among children and adolescents aged 2 to 19 years, the prevalence of obesity is 17.0% (95CI= 15.5%-18.6%). Further, rates of obesity are disproportionately high among minoritized youth. The prevalence of children and adolescents with obesity is lower among White children compared to Black children (14.7% vs. 19.5%) or Hispanic children (14.7% vs. 21.9%). Disparities by socioeconomic status exist as well. Prevalence of children with obesity from households with an income that is \u3e350% of the federal poverty threshold (after accounting for household size) is significantly less compared to children from households with an income that is \u3c130% of the federal poverty threshold (10.9% vs 18.9%). Disparities exist by location as well. A recent systematic review concluded that children who reside in rural areas are 2.6 times more likely to have obesity when compared to their urban counterparts. Although children in rural areas have more obesity, this prevalence might differ based on the definition of rural used. Finally, evidence shows children gain 3-5 times the amount of weight and lose cardiorespiratory fitness (CRF) during summer compared to the 9-months of the school year. Notably, this trend is more pronounced in children who are already overweight or obese going into summer and/or from low-income or minoritized households. To our knowledge, no studies have examined summer weight gain by location or rurality status (i.e., exurban vs urban). The purpose of study 1 was to examine accelerations in body composition (BMI, age-sex specific zBMI, and 95th percentile of BMI [%BMIp95] gain) during the summer months by school locality (i.e., urban, suburban, exurban). This study utilized the Early Childhood Longitudinal Study Kindergarten Class of 2010-2011 (ECLS-K:2011), a complex multistage probability sample from the population of U.S. children who were enrolled to attend kindergarten in the fall of 2010. ECLS-K:2011 data were restricted to those participants with height and weight measured within specific time periods (August/September and April/May) to appropriately examine accelerations in body composition gain during the summer months and school year. A total of 1,549 children (48% female, 42% White) had at least two consecutive measures that occurred in August/September or April/May. Among all locale classifications (i.e., urban, suburban, and exurban), children from high income households comprised the largest proportions for each group (31%, 39%, and 37%) respectively. Among urban and suburban locations, Hispanic children comprised the largest proportions for both groups (43% and 44%) respectively. Among exurban locale classifications, the majority of children were white (60%). Children from suburban and exurban schools experienced significantly less accelerations in monthly zBMI gain compared to their urban counterparts -0.038 (95CI= -0.071, -0.004) and -0.045 (95CI= -0.083, -0.007) respectively. Children from exurban schools experienced significantly less acceleration in monthly %BMIp95 during the summer months when compared to the school year -0.004 (95CI= -0.007, 0.000). This is the first study to examine summer weight gain by school location. Summer appears to impact children more negatively from urban schools when compared to their suburban and exurban counterparts. The purpose of study 2 of this dissertation is to evaluate children’s proportion of days meeting behavior guidelines: moderate-to-vigorous physical activity (MVPA) ≥60minutes/day, sleep (10-13 hours/night for 5 years, 9-12 hours/night for 6-12 years), and screen-time (\u3c2 hours/day) during the school year compared to summer vacation by race and free/reduced-priced lunch (FRPL) eligibility. Children (n=268, grades=K-4, 44.1%FRPL, 59.0% Black) attending three schools participated. Children’s activity, sleep, and screen-time were collected during an average of 23 school days and 16 days during summer vacation. During school, both children who were White and eligible for FRPL met activity, sleep, and screen-time guidelines on a greater proportion of days when compared to their Black and non-eligible counterparts. Significant differences in changes from school to summer in the proportion of days children met activity (-6.2%, 95CI=-10.1%,-2.3%; OR=0.7, 95CI=0.6, 0.9) and sleep (7.6%, 95CI=2.9%,12.4%; OR=2.1, 95CI=1.4, 3.0) guidelines between children who were Black and White were observed. Differences in changes in activity (-8.5%, 95CI=- 4.9%, -12.1%; OR=1.5, 95CI=1.3, 1.8) were observed between children eligible vs. ineligible for FRPL. Summer vacation may be an important time for targeting activity and screen-time of children who are Black and/or eligible for FRPL. This complete dissertation works to further the literature exploring childhood obesity, and its behavioral mechanisms that may help to curb prevalence rates that continue to be a public health concern. Obesity prevalence by location has been established in the literature. However, less is known regarding summer weight by school location. Further, I explore the behavioral mechanisms contributing to obesity by examining the proportion of days children meet behavior guidelines during summer vacation and the school year

Examining the Association of Second Grade Children\u27s Sleep and Screen Time Recommendations

Background: Adequate sleep is essential for various health outcomes (e.g., obesity, diabetes, and cardiovascular disease). However, sleep time is threatened by the increased opportunities for unsupervised screen time available to children of all ages. The American Academy of Sleep Medicine recommends that elementary-aged children sleep between 9-12 hours per night. Further, the American Academy of Pediatrics recommends that children\u27s recreational screen time be limited to less than two hours per day. Excess screen use can delay bedtime and lead to less restful sleep. The purpose of this study was to examine the association between adhering to screentime guidelines (/day) and the likelihood of meeting sleep guidelines (9-12 hours/day) in 2nd-grade children. Methods: This study utilized two waves (2015-2016 and 2019-2020) of 2nd graders\u27 parent-reported weighted survey data from the Texas School Physical Activity and Nutrition (SPAN) cross-sectional survey. Results: The final analytic sample included (n=3,193) individuals (53% female, 62% Hispanic) across two years of data collection. 65% of parents/guardians reported their children met the sleep guidelines, while 33% of parents/guardians reported their children meeting the screentime guideline. After controlling for BMI, race/ethnicity, school disadvantage, education, sex, and year of collection, parents who reported their children met the screentime guideline had 1.53 greater odds of meeting sleep guidelines compared to children whose parent/guardians reported their children did not meet the screentime guidelines OR (1.53 95%CI = 1.18, 1.99). In stratified analyses, we found that the associations between meeting sleep and screen time guidelines were primarily true for White children. A higher proportion of white children were more likely to meet both sleep time and screen time recommendations compared to black and Hispanic children, while Black and Hispanic children were as likely to meet screen time guidelines as White children; both groups had significantly lower odds of meeting sleep guidelines compared to White children OR 0.32 (95%CI = 0.18, 0.58) and OR 0.49 (95%CI = 0.29, 0.83) respectively. Discussion: Children\u27s ability to meet the recommended sleep guidelines is associated with screentime guideline adherence. Further exploration is needed to understand racial/ethnic differences in guideline adherence for screentime and sleep. Interventions targeting sleep characteristics (e.g., duration, quality, and timing) should consider concomitantly targeting screentime adherence in elementary-aged children

Validity and Wearability of Consumer-based Fitness Trackers in Free-living Children

International Journal of Exercise Science 12(5): 471-482, 2019. Over the past decade wearable fitness trackers (WFTs) have grown in popularity with more recent versions able to capture the pulse rate noninvasively on the wrist of the wearer. Most of evidence on the validity of WFTs have explored adults in clinical settings. Thus, the purpose of this study is to 1) evaluate the validity of a wrist-placed WFT in determining heart rate, and 2) examine the wear compliance of a wrist-placed WFT, in children in free-living settings. In study 1, 19 children (5-12yrs) wore a Fitbit Charge HR© and a Polar chest strap heart rate (HR) monitor for 2 hours while performing sedentary-to-vigorous activities at a holiday camp in December 2016. In study 2, 20 children with mild developmental disabilities (8-13yrs) were asked to wear a Fitbit Alta HR© during summer 2017. In study 1, mean absolute percent difference between the WFT HR and criterion was 6.9%. Overall, \u3e75% of WFT HRs were within 5-10% of the criterion. Bland Altman plots indicated a moderate-to-high level of agreement between the WFT and criterion (mean difference 4.1%; Limits of Agreement 26.8, -18.5%). In study 2, participants had the device in their possession for 43 days (SD±14, range 14 – 56 days) and wore it on 67% of those days (range: 20 – 96%) for at least 10 hours/day. Preliminary evidence suggests that WFTs can provide comparable HR estimates to a criterion field-based measure and children can wear WFTs for extended monitoring periods in free-living settings

Children’s moderate-to-vigorous physical activity on weekdays versus weekend days:A multi-country analysis

PURPOSE: The Structured Days Hypothesis (SDH) posits that children's behaviors associated with obesity - such as physical activity - are more favorable on days that contain more 'structure' (i.e., a pre-planned, segmented, and adult-supervised environment) such as school weekdays, compared to days with less structure, such as weekend days. The purpose of this study was to compare children's moderate-to-vigorous physical activity (MVPA) levels on weekdays versus weekend days using a large, multi-country, accelerometer-measured physical activity dataset. METHODS: Data were received from the International Children's Accelerometer Database (ICAD) July 2019. The ICAD inclusion criteria for a valid day of wear, only non-intervention data (e.g., baseline intervention data), children with at least 1 weekday and 1 weekend day, and ICAD studies with data collected exclusively during school months, were included for analyses. Mixed effects models accounting for the nested nature of the data (i.e., days within children) assessed MVPA minutes per day (min/day MVPA) differences between weekdays and weekend days by region/country, adjusted for age, sex, and total wear time. Separate meta-analytical models explored differences by age and country/region for sex and child weight-status. RESULTS/FINDINGS: Valid data from 15 studies representing 5794 children (61% female, 10.7 ± 2.1 yrs., 24% with overweight/obesity) and 35,263 days of valid accelerometer data from 5 distinct countries/regions were used. Boys and girls accumulated 12.6 min/day (95% CI: 9.0, 16.2) and 9.4 min/day (95% CI: 7.2, 11.6) more MVPA on weekdays versus weekend days, respectively. Children from mainland Europe had the largest differences (17.1 min/day more MVPA on weekdays versus weekend days, 95% CI: 15.3, 19.0) compared to the other countries/regions. Children who were classified as overweight/obese or normal weight/underweight accumulated 9.5 min/day (95% CI: 6.9, 12.2) and 10.9 min/day (95% CI: 8.3, 13.5) of additional MVPA on weekdays versus weekend days, respectively. CONCLUSIONS: Children from multiple countries/regions accumulated significantly more MVPA on weekdays versus weekend days during school months. This finding aligns with the SDH and warrants future intervention studies to prioritize less-structured days, such as weekend days, and to consider providing opportunities for all children to access additional opportunities to be active

Generalized Theorems for Nonlinear State Space Reconstruction

Takens' theorem (1981) shows how lagged variables of a single time series can be used as proxy variables to reconstruct an attractor for an underlying dynamic process. State space reconstruction (SSR) from single time series has been a powerful approach for the analysis of the complex, non-linear systems that appear ubiquitous in the natural and human world. The main shortcoming of these methods is the phenomenological nature of attractor reconstructions. Moreover, applied studies show that these single time series reconstructions can often be improved ad hoc by including multiple dynamically coupled time series in the reconstructions, to provide a more mechanistic model. Here we provide three analytical proofs that add to the growing literature to generalize Takens' work and that demonstrate how multiple time series can be used in attractor reconstructions. These expanded results (Takens' theorem is a special case) apply to a wide variety of natural systems having parallel time series observations for variables believed to be related to the same dynamic manifold. The potential information leverage provided by multiple embeddings created from different combinations of variables (and their lags) can pave the way for new applied techniques to exploit the time-limited, but parallel observations of natural systems, such as coupled ecological systems, geophysical systems, and financial systems. This paper aims to justify and help open this potential growth area for SSR applications in the natural sciences

Children’s moderate-to-vigorous physical activity on weekdays versus weekend days: a multi-country analysis

Abstract: Purpose: The Structured Days Hypothesis (SDH) posits that children’s behaviors associated with obesity – such as physical activity – are more favorable on days that contain more ‘structure’ (i.e., a pre-planned, segmented, and adult-supervised environment) such as school weekdays, compared to days with less structure, such as weekend days. The purpose of this study was to compare children’s moderate-to-vigorous physical activity (MVPA) levels on weekdays versus weekend days using a large, multi-country, accelerometer-measured physical activity dataset. Methods: Data were received from the International Children’s Accelerometer Database (ICAD) July 2019. The ICAD inclusion criteria for a valid day of wear, only non-intervention data (e.g., baseline intervention data), children with at least 1 weekday and 1 weekend day, and ICAD studies with data collected exclusively during school months, were included for analyses. Mixed effects models accounting for the nested nature of the data (i.e., days within children) assessed MVPA minutes per day (min/day MVPA) differences between weekdays and weekend days by region/country, adjusted for age, sex, and total wear time. Separate meta-analytical models explored differences by age and country/region for sex and child weight-status. Results/findings: Valid data from 15 studies representing 5794 children (61% female, 10.7 ± 2.1 yrs., 24% with overweight/obesity) and 35,263 days of valid accelerometer data from 5 distinct countries/regions were used. Boys and girls accumulated 12.6 min/day (95% CI: 9.0, 16.2) and 9.4 min/day (95% CI: 7.2, 11.6) more MVPA on weekdays versus weekend days, respectively. Children from mainland Europe had the largest differences (17.1 min/day more MVPA on weekdays versus weekend days, 95% CI: 15.3, 19.0) compared to the other countries/regions. Children who were classified as overweight/obese or normal weight/underweight accumulated 9.5 min/day (95% CI: 6.9, 12.2) and 10.9 min/day (95% CI: 8.3, 13.5) of additional MVPA on weekdays versus weekend days, respectively. Conclusions: Children from multiple countries/regions accumulated significantly more MVPA on weekdays versus weekend days during school months. This finding aligns with the SDH and warrants future intervention studies to prioritize less-structured days, such as weekend days, and to consider providing opportunities for all children to access additional opportunities to be active

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Increasing frailty is associated with higher prevalence and reduced recognition of delirium in older hospitalised inpatients: results of a multi-centre study

Purpose: Delirium is a neuropsychiatric disorder delineated by an acute change in cognition, attention, and consciousness. It is common, particularly in older adults, but poorly recognised. Frailty is the accumulation of deficits conferring an increased risk of adverse outcomes. We set out to determine how severity of frailty, as measured using the CFS, affected delirium rates, and recognition in hospitalised older people in the United Kingdom. Methods: Adults over 65 years were included in an observational multi-centre audit across UK hospitals, two prospective rounds, and one retrospective note review. Clinical Frailty Scale (CFS), delirium status, and 30-day outcomes were recorded. Results: The overall prevalence of delirium was 16.3% (483). Patients with delirium were more frail than patients without delirium (median CFS 6 vs 4). The risk of delirium was greater with increasing frailty [OR 2.9 (1.8–4.6) in CFS 4 vs 1–3; OR 12.4 (6.2–24.5) in CFS 8 vs 1–3]. Higher CFS was associated with reduced recognition of delirium (OR of 0.7 (0.3–1.9) in CFS 4 compared to 0.2 (0.1–0.7) in CFS 8). These risks were both independent of age and dementia. Conclusion: We have demonstrated an incremental increase in risk of delirium with increasing frailty. This has important clinical implications, suggesting that frailty may provide a more nuanced measure of vulnerability to delirium and poor outcomes. However, the most frail patients are least likely to have their delirium diagnosed and there is a significant lack of research into the underlying pathophysiology of both of these common geriatric syndromes