Two-level Regression Models Research Articles

Is a sense of community based on similarity? The perception of shared values and citizens’ EU identity

ABSTRACT Does the perception of sharing values strengthen the EU citizens’ sense of belonging to the European Union? The present study uses the concept of social identity derived from social psychology to explore this question. It assumes that the perception that EU citizens share the same value orientations with each other strengthens identification with the EU’s political community. To empirically test this thesis, two-level regression models are conducted on the basis of survey data from the 2019 Eurobarometer (EB 92.3). The empirical results show that the subjective perception of being similar in terms of value orientations is positively associated with EU identity.

MULTILEVEL REGRESSIONS FOR MODELING MEAN SCORES OF NATIONAL EXAMINATIONS

National Exam known as UN score is the final evaluation to determine the achievement of national graduate competency standards in the school. The determinants of the achievement of the standards can’t be separated from the role of schools and local governments in which this regard is known as nested. In the field of statistics, this phenomenon can be described with a multilevel model, where level-1 is the school while level-2 is the district where the school is located. Several multilevel models are used to describe the phenomenon, the result shows that the two-level regression model without interaction is selected as the best model and the variables which affect the UN average scores significantly at level-1 are school status , the ratio between laboratories and students , while the variable at level-2 is expenditure per capita of district/city . From this study, that educational institutions' steps in achieving a graduation standard can be right on the target.

Physical activity improves stress load, recovery, and academic performance-related parameters among university students: a longitudinal study on daily level

BackgroundPhysical activity has been proven to be beneficial for physical and psychological health as well as for academic achievement. However, especially university students are insufficiently physically active because of difficulties in time management regarding study, work, and social demands. As they are at a crucial life stage, it is of interest how physical activity affects university students' stress load and recovery as well as their academic performance.MethodsStudent´s behavior during home studying in times of COVID-19 was examined longitudinally on a daily basis during a ten-day study period (N = 57, aged M = 23.5 years, SD = 2.8, studying between the 1st to 13th semester (M = 5.8, SD = 4.1)). Two-level regression models were conducted to predict daily variations in stress load, recovery and perceived academic performance depending on leisure-time physical activity and short physical activity breaks during studying periods. Parameters of the individual home studying behavior were also taken into account as covariates.ResultsWhile physical activity breaks only positively affect stress load (functional stress b = 0.032, p < 0.01) and perceived academic performance (b = 0.121, p < 0.001), leisure-time physical activity affects parameters of stress load (functional stress: b = 0.003, p < 0.001, dysfunctional stress: b = -0.002, p < 0.01), recovery experience (b = -0.003, p < 0.001) and perceived academic performance (b = 0.012, p < 0.001). Home study behavior regarding the number of breaks and longest stretch of time also shows associations with recovery experience and perceived academic performance.ConclusionsStudy results confirm the importance of different physical activities for university students` stress load, recovery experience and perceived academic performance in home studying periods. Universities should promote physical activity to keep their students healthy and capable of performing well in academic study: On the one hand, they can offer opportunities to be physically active in leisure time. On the other hand, they can support physical activity breaks during the learning process and in the immediate location of study.

The Effects of Ying Yang Bao on Nutritional Status of Children Aged 6-60 Months in Underdeveloped Rural Areas of China.

The Ying Yang Bao (YYB) intervention, a national policy in China, has been implemented for over two decades. Most previous studies have focused only on the short-term effects of YYB, while the long-term effects remain unexplored. This study was designed to evaluate the long-term effects of YYB in children aged 6-60 months. A sample of 4666 children was divided into intervention and control groups. Information on basic characteristics, physical examination, YYB consumption, etc., was obtained annually from 2018 to 2021. T-tests or chi-square tests were used to compare differences between the groups for continuous or categorical variables. Children in the intervention group showed greater incremental improvements in hemoglobin levels and physical development (p < 0.05). Prevalence of anemia, underweight, and stunting were lower in the intervention group than in the control group (all p < 0.05). Two-level regression models were constructed to assess the long-term effects of YYB. YYB reduced the risk of anemia and wasting by 37% (OR: 0.63, 95% CI: 0.52-0.75) and 49% (OR: 0.51, 95% CI: 0.39-0.67), respectively. This study indicates that YYB could significantly improve the nutritional status of children aged 6-60 months in underdeveloped rural areas of China.

Do Fundamental Movement Skill Domains in Early Childhood Predict Engagement in Physical Activity of Varied Intensities Later at School Age? A 3-Year Longitudinal Study

This study was conducted to determine how total fundamental movement skill (FMS) score and, separately, locomotor skill (LMS), and object control skill scores in children 3–8 years old predicted their specific-intensity physical activity 3 years later. Overall, 441 Finnish children (51.7% female, baseline mean age of 5.6 years) participated in the study. Total FMS, LMS, and object control skill scores were assessed using the Test of Gross Motor Development, third edition. The time spent engaged in physical activity of different intensities (light, moderate, vigorous, moderate-to-vigorous, light-to-vigorous, and sedentary behavior) was determined using accelerometers. A two-level regression model was used in the analysis, considering potential covariates and interactions. The results showed that moderate physical activity, vigorous physical activity, and moderate-to-vigorous physical activity were predicted by the total FMS score (β = 0.177 to 0.203, p = .001–.003) and the LMS score (β = 0.140 to 0.164, p = .004–.014), but not the object control skill score. Moreover, the LMS score inversely predicted sedentary behavior (β = −0.116, p = .042). In conclusion, higher FMS and, specifically, LMS scores seem to predict more engagement in moderate-to-vigorous physical activity and less sedentary behavior over time. However, most of the variance in physical activity remains unexplained.

Bayesian estimation for the random moderation model: effect size, coverage, power of test, and type І error.

The random moderation model (RMM) was developed based on a two-level regression model to cope with heteroscedasticity in moderation analysis, and normal-distributed-based maximum likelihood (NML) estimation was developed to estimate the RMM. To present an alternative to the NML, this article discusses the effectiveness of Bayesian estimation for the RMM, aiming to explore a more practical method using the popular software Mplus. Through a simulation study, the RMM based on Bayesian estimation was investigated and compared to maximum likelihood (ML) estimations, including the NML and the default ML estimation in Mplus. The results indicated that the Bayesian approach outperformed the two ML estimations. It showed (a) higher accuracy for estimation of the effect size of the moderation effect; (b) higher 95% credibility interval coverage of the true value of the moderation effect; and (c) well-controlled and more stable type I error rates, while powers comparable to the ML estimations were provided.

Epistemic beliefs in science, socio-economic status, and mathematics and science test results in lower secondary education: a multilevel perspective

The role of epistemic beliefs in science (EBS) and socio-economic status (SES) on mathematics and science test results on both student- and school-level data was investigated via a secondary analysis of Estonian Programme for International Student Assessment (PISA) 2015 survey data. The effective sample comprised 3991 students (52% girls, 48% boys) from 81 schools. Complementing bivariate correlation analysis, two-level regression models were computed where mathematics and science test scores were predicted from student- and school-level EBS as well as SES. Mathematics and science test scores had a medium-sized correlation with both EBS as well as SES on the student-level data. These correlations were larger on the school-level data. Multilevel analyses showed that both higher mathematics and science scores were predicted by male gender, higher student-level SES and EBS, and higher school-level SES. Higher school-level EBS significantly predicted better science test scores, but this was not the case with mathematics.

Object-oriented Model to Predict Crop Yield Using Satellite-based Vegetation Index

Different models had been developed to predict crop yields based on remotely sensed data. Most approaches were based on developing empirical relationships between the Satellite based Normalized difference vegetation index NDVI data and the crop yield. This article proposes to introduce methodological framework for constructing an object-oriented yield prediction model using satellite data based on the two-level regression models; with taken into consideration the trend caused by the influence of technological improvements. Regression models for the wheat and barley crop yield predictions have been developed for twenty-seven typical districts in the Voronezh region. The two-level regression model, including FSR technique firstly to select the set of features that reflect the spatial variations in crops, soil, agriculture management within districts, after carry out the steps of exploratory data analysis EDA, objects creation and zonal average of each object. Whereas the second level consist of yield prediction with multiple linear regression MLR, Least Absolute Shrinkage and Selection Operator Lasso, Support vector machines SVM techniques. The absolute error between the predicted and observed yields of 2011-2014 years was not exceed 19(16) centner/ha for wheat(barley) at worst case. In spite of that the SVM technique outperforms rest techniques by average RMSE of 5.59(4.51) for wheat(barley).

Moderation analysis and its effect size based on a two-level regression model

<p id="p00005">In recent years, multiple regression has been widely used in social sciences to analyze the moderating effect. However, this practice was found to have at least four weaknesses. First, the concept of moderation is artificially treated as interaction. Second, the role of the predictor X is confounded with that of the moderator Z. That is, the roles of the predictor and the moderator are statistically indistinguishable, or the moderation effect of Z equals that of X. Third, the assumption of homoscedasticity of error variances across different values of X and Z is often violated by data in social and behavioral sciences. Violating this assumption often results in an inflated Type Ⅱ error rate and a low power. Fourth, △R² does not directly measure the effect of moderation as conceptually defined. That is, a measure that reflects the impact of Z on the relationship between X and Y (i.e., X→Y) should be used to quantify the moderating effect. <br/>Compared to multiple regression, the two-level regression model has many advantages in the analysis of moderating effect. First, the two-level regression model does not require the homoscedasticity assumption in moderation analysis. Second, the two-level regression model allows the regression coefficients of a dependent variable Y on predictor X (i.e., X→Y) are further regressed on moderator variables Z. Therefore, the two-level regression model permits estimating the percentage of variance of each regression coefficient that is due to moderator variables (i.e., the moderation effect size). The two-level regression model directly shows us to what extent a moderator explains the variance of the regression coefficient between the dependent variable and the predictor. <br/>At the present study, we propose a procedure to analyze the moderating effect based on the two-level regression model. The first step is to determine the moderating effect using the two-level regression model. If the variance of the error εi1 of the level 2 slope equation is statistically significant, the result of the two-level regression model and the corresponding effect size should be reported. Otherwise, go to the second step. In the second step, multiple regression was used to work out the moderating effect. If the Bayesian information criterion of the two-level regression model is smaller than that of the multiple regression, the result of the two-level regression model and the corresponding effect size should be reported. Otherwise, the result of the multiple regression and the corresponding effect size △R² should be reported. <br/> We exemplify how to conduct the proposed procedure by using Mplus. It is noteworthy that, with this software, a two-level regression model could be built via a “trick” for 2-level model with single level data. The Mplus syntax is offered to facilitate the implementation of two-level regression model in analyzing moderated mediation effects. The program can be managed easily by empirical researchers. <br/>Directions for future study on two-level regression model are discussed at the end of the paper. First, if data contains outliers or heavy tails, robust methods of two-Level regression model should be adapted. Second, if the measurement error of the variables needs to be taken into account, two-level moderated latent variable model should be adapted. Third, two-level regression model could be used to analyze the mediated moderation model and moderated mediation model.

The association between community-level socioeconomic status and cognitive function among Chinese middle-aged and older adults: a study based on the China Health and Retirement Longitudinal Study (CHARLS)

BackgroundAlthough numerous studies focused on the relationship between area socioeconomic status (SES) and health, only a few of them investigated how community-level SES was linked to late-life cognitive function as well as the potential pathways underlying this association, and very few of them focused on the context of China. This study examined how community-level SES was linked to cognitive function and the potential pathways underlying this association among middle-aged and older adults in China.MethodsData was drawn from the waves 1–4 of China Health and Retirement Longitudinal Study. We measured cognitive function with the components of the Telephone Interview of Cognitive Status battery. Community-level SES was derived from a sum of z scores of the percentage of the illiterate and the per-capita net income status within communities. We adopted two-level hierarchical linear regression models to explore the associations between community-level SES and cognitive function. A multilevel mediation analysis with structural equation modeling was undertaken to disaggregate the direct and indirect pathways of the associations.ResultsHigher community-level SES was associated with better cognitive function (β = 0.562, 95% CI = 0.390, 0.734), and this significant association was only present in rural participants, not in urban participants. Furthermore, we discovered the mediating effects of outdoor exercise facilities within communities (β = 0.023, 95% CI = 0.000, 0.056) and individual-level SES (β = 0.108, 95% CI = 0.057, 0.156) to explain the relationship between community SES and cognitive function.ConclusionsThese findings highlight the importance of community environmental interventions in maintaining individuals’ cognitive health in China, especially for older adults. Our results provided solid empirical evidence for reducing mental health inequalities in China, and suggested that developing an aging-friendly environment and properly distributing community resources are important to improve cognitive function of older adults.

Moving Beyond Individual-Level Explanations: Exploring the Contextual Correlates of Mass Murder

Due to the rarity of mass murder, scholars have focused almost exclusively on its individual-level risk factors, assuming that structural characteristics play a negligible role in the etiology of this infrequent but impactful crime. This study explores whether local structural factors influence the incidence rate of mass murder and its logical comparison group, homicide. Using information from a novel mass killing database as well as the Supplementary Homicide Reports (SHR), two-level count regression models examine the county- and state-level factors that predict the number of mass murder ( N = 549) and homicide incidents ( N = 274,399) in 3,143 U.S. counties from 2000 to 2018. Results indicate that mass murder is more likely to occur in disadvantaged and racially/ethnically heterogeneous areas, similar to homicide in general. Future research should examine both perpetrators and their environments instead of assuming that mass murders are exclusively driven by individual-level factors.

Swedish intrauterine growth reference ranges for estimated fetal weight

Fetal growth restriction is a strong risk factor for perinatal morbidity and mortality. Reliable standards are indispensable, both to assess fetal growth and to evaluate birthweight and early postnatal growth in infants born preterm. The aim of this study was to create updated Swedish reference ranges for estimated fetal weight (EFW) from gestational week 12–42. This prospective longitudinal multicentre study included 583 women without known conditions causing aberrant fetal growth. Each woman was assigned a randomly selected protocol of five ultrasound scans from gestational week 12 + 3 to 41 + 6. Hadlock’s 3rd formula was used to estimate fetal weight. A two-level hierarchical regression model was employed to calculate the expected median and variance, expressed in standard deviations and percentiles, for EFW. EFW was higher for males than females. The reference ranges were compared with the presently used Swedish, and international reference ranges. Our reference ranges had higher EFW than the presently used Swedish reference ranges from gestational week 33, and higher median, 2.5th and 97.5th percentiles from gestational week 24 compared with INTERGROWTH-21st. The new reference ranges can be used both for assessment of intrauterine fetal weight and growth, and early postnatal growth in children born preterm.

Swedish intrauterine growth reference ranges of biometric measurements of fetal head, abdomen and femur

Ultrasonic assessment of fetal growth is an important part of obstetric care to prevent adverse pregnancy outcome. However, lack of reliable reference ranges is a major barrier for accurate interpretation of the examinations. The aim of this study was to create updated Swedish national reference ranges for intrauterine size and growth of the fetal head, abdomen and femur from gestational week 12 to 42. This prospective longitudinal multicentre study included 583 healthy pregnant women with low risk of aberrant fetal growth. Each woman was examined up to five times with ultrasound from gestational week 12 + 3 to 41 + 6. The assessed intrauterine fetal biometric measurements were biparietal diameter (outer–inner), head circumference, mean abdominal diameter, abdominal circumference and femur length. A two-level hierarchical regression model was employed to account for the individual measurements of the fetus and the number of repeated visits for measurements while accounting for the random effect of the identified parameterization of gestational age. The expected median and variance, expressed in both standard deviations and percentiles, for each individual biometric measurement was calculated. The presented national reference ranges can be used for assessment of intrauterine size and growth of the fetal head, abdomen and femur in the second and third trimester of pregnancy.

Migration Status, Internet Use, and Social Participation among Middle-Aged and Older Adults in China: Consequences for Depression.

This study aimed to examine the underlying relationship between migration status and depressive symptoms among middle-aged and older adults in China. Data were derived from three waves of panel data (2011, 2013, and 2015) from the China Health and Retirement Longitudinal Study. Two-level regression models and generalized structural equation modeling were run to fit the data. The results showed that migration status of the respondents could ameliorate their depression ( = −0.02, p < 0.01), so did internet use ( = −0.02, p < 0.001), and social participation ( = −0.06, p < 0.001). The indirect effects of migration status on depression through internet use and of internet use on depression through social participation existed. The effects of migration status, internet use, and social participation in decreasing depression were discussed. Provided the associations among migration status, internet use, social participation, and depression, attention should be paid on increasing protective aspects of migration among middle-aged and older adults, such as internet use and social participation, to enhance their mental health.

Abstract MP48: Sex Difference, Circulating Short-chain Fatty Acids, Dietary Sodium Reduction in Untreated Hypertensives: A Randomized, Double-Blind, Placebo-Controlled Trial

Introduction: Short-chain fatty acids (SCFAs) are products from the fermentative activity of gut bacteria and almost all circulating SCFAs are microbial in origin. Emerging evidence suggests that circulating SCFAs play a role in blood pressure (BP) control through the host receptors. Animal studies demonstrate that high salt diet modulates the gut microbiome and SCFAs. Moreover, gut microbiome contributes to sex differences in BP regulation. Hypothesis: We tested the hypothesis that the modest sodium reduction would alter circulating SCFAs among untreated hypertensives, and the changes in SCFAs would be associated with reduced blood pressure (BP) and improved cardiovascular phenotypes. Moreover, there would be sex differences in circulating SCFA response to sodium reduction. Methods: A total of 145 subjects (42% blacks, 19% Asian, 34% females) were included from a completed randomized, double-blind, placebo-controlled crossover trial of sodium restriction with slow sodium or placebo, each for 6 weeks. Targeted circulating SCFA profiling was performed in paired serum samples, which were collected at the end of each period, so as all outcome measures. Two-level mixed-effects linear regression models were used to assess the differences in SCFAs between sodium and placebo tablets while incorporating repeated measured data and controlling for age, sex and BMI as confounding variables. We further tested whether the changes in the SCFAs were associated with the changes in BPs, and cardiovascular phenotypes using mixed-effects models. Results: Sodium reduction increased all 8 SCFAs, among which the increases in 2-methylbutyrate, butyrate, hexanoate, isobutyrate, and valerate were statistically significant ( p &lt;0.05). The increased SCFAs were associated with decreased BP and improved capillary density. There were significant sex differences of SCFAs in response to sodium reduction ( p &lt;0.05). When stratified by sex, the increases in butyrate, hexanoate, isobutyrate, isovalerate, and valerate were significant only in women ( p &lt;0.05), but none were significantly changed in men ( p &gt;0.05). In women, increased isobutyrate, isovalerate, and 2-methylbutyrate were inversely associated with reduced BPs ( p &lt;0.05). Additionally, increased valerate was associated with decreased carotid-femoral pulse wave velocity (cf-PWV) ( p =0.04). Conclusions: Our results show that dietary sodium reduction increases SCFAs, suggesting that dietary sodium may influence the gut microbiome in humans given almost all SCFAs are microbial in origin. Moreover, increased circulating SCFAs are associated with decreased BPs, improved arterial compliance, and increased capillary density. The sex differences in SCFA response to dietary sodium reduction warrants further investigation.

A Two-level Moderated Latent Variable Model with Single Level Data

With single-level data, Yuan, Cheng and Maxwell developed a two-level regression model for more accurate moderation analysis. This article extends the two-level regression model to a two-level moderated latent variable (2MLV) model, and uses a Bayesian approach to estimate and test the moderation effects. Monte Carlo results indicate that: 1) the new method yields more accurate estimate of the interaction effect than those via the product-indicator (PI) approach and latent variable interaction (LVI) with single-level model, both are also estimated via Bayesian method; 2) the coverage rates of the credibility interval following the 2MLV model are closer to the nominal 95% than those following the other methods; 3) the test for the existence of the moderation effect is more reliable in controlling Type I errors than both PI and LVI, especially under heteroscedasticity conditions. Moreover, a more interpretable measure of effect size is developed based on the 2MLV model, which directly answers the question as to what extent a moderator can account for the change of the coefficient between the predictor and the outcome variable. A real data example illustrates the application of the new method.

Abstract 311: Trajectory of Risk-Standardized Survival Rates for In-Hospital Cardiac Arrest

Introduction: Risk-standardized survival rate (RSSR) for in-hospital cardiac arrest (IHCA) has emerged as an important metric to measure and incentivize resuscitation quality at a hospital-level. We examined whether hospital performance on the RSSR metric was generally stable year-over-year. Methods: We used data from 81,795 adult patients with an IHCA from 163 hospitals with continuous participation in Get With The Guidelines-Resuscitation from 2012 to 2017. A two-level hierarchical regression model was used to compute RSSRs for 2 time intervals (baseline: 2012-13; follow-up: 2014-17). Hospitals were classified as top-, middle- and bottom-performing if they ranked in the top 25%, middle 50%, and bottom 25% on the RSSR metric during 2012-2013. We examined the trajectory of top, middle, and bottom-performing hospitals’ RSSR during 2014-2017 (follow-up). Results: During 2012-2013, 41 hospitals were identified as top-performing (median RSSR 31.9%), 81 as middle-performing (median RSSR 24.9%) and 41 as bottom-performing (median RSSR 18.5%). During 2014-2017, more than 3/4 th (75.6%) of top-performing hospitals remained in the top 50% and 53.7% remained in the top 25% (Table). In contrast, most (81.5%) bottom-performing hospitals ranked in the bottom 50%, and 56.1% remained in the bottom 25% during 2014-2017. Performance of middle-performing hospitals on the RSSR metric was variable. Importantly, rankings improved by at least 1 quartile ( &gt; 25 percentile points) at 26.8% and by at least 2 quartiles ( &gt; 50 percentile points) at 12.2% bottom-performing hospitals (Table). Likewise, rankings at 31.7% and 19.5% of top-performing hospitals worsened by at least 25 and 50 percentile points during 2014-2017, respectively. Conclusion: Hospital performance on RSSR during a baseline period was generally consistent with their performance during follow up. However, percentile rankings changed markedly over time at a small proportion of top- and bottom-performing hospitals.

Veterinary Students’ Beliefs About Animal Sentience: What Role Does Gender Play?

ABSTRACTAcross a 15-year period, annual cohorts of first-year veterinary science students (n = 1,380; 77% female) at a British university completed the Belief in Animal Sentience (BiAS) questionnaire, in which they reported their beliefs about the sentience (capacity to feel) of ten species: dogs, cats, lions, pigs, sheep, rats, rabbits, chickens, bees, and spiders. On the basis of previous findings regarding people’s beliefs about animals’ capacities for mind, it was hypothesized that female students would ascribe more human-like sentience to animals than would male students. It was also hypothesized that the proportion of female students in each of the cohorts studied would have an influence on the beliefs of the year group as a whole: cohorts comprising a larger percentage of women would have higher animal sentience beliefs in both males and females. The data were analyzed using two-level regression models to concurrently investigate the effects of individual respondents’ gender and the percentage of female students in their cohort. Compared with their male counterparts, female veterinary students across all the cohorts studied attributed significantly higher (more human-like) sentience to each of the ten animals listed in the BiAS questionnaire, but the percentage of female students in each year group was not associated with students’ sentience beliefs. It was also found that childhood experience of having owned pet cats or dogs was related to students’ beliefs about the sentience of these species, although this association did not contribute to the differences found between male and female respondents. Given the increasing number of women entering the veterinary profession, and previous findings that beliefs about animals’ capacities for sentience may be associated with the veterinary care they are given, we conclude that gender differences in sentience beliefs could have a significant impact on the future of veterinary practice and patient welfare.

Impacts of urban form on air quality: Emissions on the road and concentrations in the US metropolitan areas

In the United States (US), one of the effects of urban sprawl is more vehicular travel. The increase in emissions from road traffic renders air quality management unsuccessful, in spite of the efforts of the US Environmental Protection Agency (EPA), operating under the Clean Air Act, which does not regulate land use. As an alternative to urban sprawl, the US-EPA has initiated smart growth strategies based on compact development. In this study, the impacts of metropolitan-level urban form, as a measure of urban compactness/sprawl, was explored with respect to air quality in terms of NOx and PM2.5 emissions on the road and NO2 and PM2.5 concentrations in US metropolitan areas. Ordinary least squares (OLS) and two-level regression models that control for metropolitan-level socioeconomic and local-level geographic covariates were established. The results showed that high land use mixing is one of the compactness/sprawl factors (i.e., low sprawl) that reduces per-person NOx and PM2.5 emissions on the road. While metropolitan-level urban form (i.e. high compactness) had a negative effect on PM2.5 concentrations, local environmental conditions, such as local ambient roads and emissions facilities, had greater impacts on NO2 and PM2.5 concentrations than the urban form. Based on the findings in this study, urban planners and decision makers need to establish policies and practices at two scales when planning urban development: (1) the reduction of emissions from road traffic by managing metropolitan-level urban form and (2) the reduction of emissions concentrations through managing local emissions sources near populated areas.

L-theanine and Caffeine Improve Sustained Attention, Impulsivity and Cognition in Children with Attention Deficit Hyperactivity Disorders by Decreasing Mind Wandering (OR29-04-19)

ObjectivesOur previous research corroborate the work of others to indicate that L-theanine and caffeine are known to improve sustained attention in healthy adults. The effects of these substances have not been studied in relation to attention deficit hyperactivity disorders (ADHD). We aimed to examine the effects of L-theanine, caffeine and their combination on sustained attention, impulse control and overall cognition in male children with ADHD in a four-way, placebo-controlled repeated measures crossover study. MethodsFive male children (8–17) years with ADHD, who have responded to stimulants were recruited via advertisement. L-theanine (2.5 mg/kg body weight), caffeine (2.0 mg/kg body weight), their combination and a placebo were administered in a randomized crossover design on four separate days. Functional magnetic resonance imaging (fMRI) was performed 55 minutes post-dose, while the subjects engaged in a Go/NoGo continuous performance task (CPT) and a stop-signal reaction time (SSRT) task. NIH Cognition Toolbox was administered 110 minutes post-dose. Data were analyzed using two-level regression models constructed using R and FSL software to compare the three treatments vs. the placebo on all measured outcomes. ResultsL-theanine, caffeine and their combination improved hit rate in CPT (p < 0.001) and total cognition composite in NIH Cognition Toolbox (p < 0.05) compared to placebo. L-theanine and caffeine, when administered alone, increased SSRT (p = 0.007 and p = 0.018 respectively), while the combination decreased SSRT compared to placebo (p = 0.012). L-theanine, caffeine and the combination decreased task-related fMRI reactivity of the default mode network in the brain, which is known to show increased activity during mind wandering. ConclusionsL-theanine, caffeine and their combination seem to improve sustained attention and overall cognitive performance in children with ADHD, possibly via decreasing mind wandering during exertion of attention. While L-theanine alone and caffeine alone seem to increase impulsivity, the combination seems to decrease (i.e., improve) impulsivity in children with ADHD. As such, the combination of L-theanine and caffeine may have the potential to be used as a therapeutic and/or dose sparing agent to manage symptoms in children with ADHD. Funding SourcesTexas Tech Neuroimaging Institute.