A clash of constructs? : re-examining grit in light of academic buoyancy and future time perspective

Grit, defined as perseverance and passion for long-term goals, has been found to be a powerful predictor of student success and persistence. Yet, it has been recently scrutinized construct due to weaknesses in discriminant and predictive validity of its measure. To investigate these issues further, I examined grit, its dimensions (perseverance of effort and consistency of interest), and other motivational factors--academic buoyancy and future time perspective--to test whether they were distinct constructs, and whether they were predictors of academic achievement, incorporating individual differences in gender, ethnicity, and major. The current study revealed that grit positively predicted undergraduates’ GPA (N = 328) over and beyond demographic and other motivational variables. Regarding individual differences, men and women differed on subscales of future time perspective, and Asian Americans reported lower grit compared to White and Hispanic students, despite higher GPA compared to Hispanics. The relevance of the findings is discussed along with implications for research and practice.Educational Psycholog

Sedentary lifestyle and obesity in adults

Excessive time spent on sedentary behavior (SB) can increase the risks of obesity, regardless of engagement in physical activity (PA). Subjective and objective measures are both available to assess SB but little is known about the relative utility of these measures for epidemiological research. The purposes of this dissertation were to 1) evaluate the accuracy of 24-hour Physical Activity Recall (24PAR) relative to SenseWear Armband (SWA) for assessing SB, 2) characterize the context of SB by demographic indicators, and 3) determine the independent/joint associations of SB and PA with obesity by the 24PAR versus SWA. The first study demonstrated that the 24PAR had small errors for estimating total sedentary time, but larger errors for other definitions of SB (i.e. non-sleep, and non-sleep non-lying sedentary time). Moreover, extremely or minimally sedentary individuals had larger errors than moderately sedentary individuals. Older and/or heavier individuals tended to underestimate sedentary time more than younger and/or lighter individuals. The second study provided unique insights about the context of SB. Individuals with varying levels of socio-demographic variables exhibited differential patterns of `where\u27 and `why\u27 they spent time being sedentary. The third study found detrimental effects of excessive SB and beneficial effects of sufficient PA on obesity based on the objective estimates from the SWA. Analyses based on the subjective estimates from the 24PAR revealed significant associations with the PA outcome but these associations were weaker than the associations with the SWA. These results demonstrate that the objectivity and validity of the measures influences the ability to examine health outcomes. This dissertation advances understanding about the underlying nature of sedentary lifestyles and its relation to obesity at the population level. The study utilized two promising measurement tools to obtain both objective and subjective measures of SB. The objective tool served as the criterion and provided strong associations between SB, PA and obesity. The subjective tool was found to have utility for examining the context of SB, but exhibited substantial measurement error, leading to null and/or weak associations with obesity. Future research is required to develop measurement error models to correct for recall biases of the 24PAR

Characterizing the context of sedentary lifestyles in a representative sample of adults: a cross-sectional study from the physical activity measurement study project.

BACKGROUND: Research has clearly demonstrated that excess time spent on sedentary behavior (SB) increases health risks in the population. However, the lack of information on the context of SB in the population prevents a detailed understanding of sedentary lifestyles. The purpose of this study was to characterize the context of SB in a representative sample of adults and to examine differences across various socio-demographic indicators. METHODS: A diverse sample of 1442 adults (ages 20-71 year) completed an interviewer-administered 24-h activity recall to provide detailed information about the time, type and location of the previous day's activities. All reported activities were matched with MET scores from the Compendium of Physical Activity but only SB (i.e., METS < 1.5) were extracted for the present analyses. RESULTS: The reported SB were broadly distributed across 5 primary location categories (Work: 27.5%, Community: 24.8%, Home/Indoor: 20.5%, Home/Outdoor: 15.8%, and Transportation: 11.3%). Patterns of SB allocations varied considerably across different socio-demographic indicators indicating the extreme variability in SB in the population. CONCLUSIONS: The findings provide unique insights about the context of SB at the population level, and can serve as a guide for developing intervention/policy studies to reduce sedentary time and minimize disparities in SB

A Random Effect Model Approach to Survey Data Integration

Combining information from several surveys, or survey integration, is an important practical problem in survey sampling. When the samples are selected from similar but different populations, random effect models can be used to describe the sample observations and to borrow strength from multiple surveys. In this paper, we consider a prediction approach to survey integration assuming random effect models. The sampling designs are allowed to be informative. The model parameters are estimated using a version of EM algorithm accounting for the sampling design. The mean squared error estimation is also discussed. Two limited simulation studies are used to investigate the performance of the proposed method

The contributing role of physical education in youth’s daily physical activity and sedentary behavior

Background: School physical education (PE) is considered as an effective channel for youth to accumulate moderate-to-vigorous physical activity (MVPA) and reduce sedentary time. The purpose of this study was to determine the contributing role of PE in daily MVPA and sedentary time among youth. Methods: The study recruited 67 sixth grade children (29 boys; Mean age = 11.75) from two suburban schools at a U.S. Midwest state, 48 of whom contributed ≥10 hours of physical activity (PA) data per day were included for analysis. An objective monitoring tool (i.e., Sensewear armband monitor) was used to capture the participants’ MVPA and sedentary time for 7–14 days. Pearson product–moment correlation analysis (r), multi-level regression analyses, and analysis of variance were conducted for data analysis. Results: MVPA and sedentary time in PE showed significant positive associations with daily MVPA and sedentary time, respectively (r = 0.35, p \u3c 0.01; r = 0.55, p \u3c 0.01). Regression analyses revealed that one minute increase in MVPA and sedentary behavior in PE was associated with 2.04 minutes and 5.30 minutes increases in daily MVPA and sedentary behavior, respectively, after controlling for sex and BMI. The participants demonstrated a significantly higher level of MVPA (p = .05) but similar sedentary time (p = 0.61) on PE days than on non-PE days. Boys had significantly more daily MVPA (p \u3c .01) and less sedentary time (p \u3c .01) than girls; while higher BMI was associated with more sedentary time (p \u3c .01). Conclusions: PE displayed a positive contribution to increasing daily MVPA and decreasing daily sedentary time among youth. Active participation in PE classes increases the chance to be more active and less sedentary beyond PE among youth

Exercise and cancer mortality in Korean men and women: a prospective cohort study.

BACKGROUND: Little is known about longitudinal associations of exercise with different types of cancer, particularly in Asian populations. The purpose of this research was to estimate the association between the duration of exercise and all-cause and cancer-specific mortality. METHOD: Data were obtained from the Korean Metabolic Syndrome Mortality Study (KMSMS), a prospective cohort study of 303,428 Korean adults aged 20 years or older at baseline between 1994 and 2004 after exclusion of individuals with missing variables on smoking and exercise. Death certificate-linked data until 31 December 2015 were provided by the Korean National Statistical Office. Cox regression models were constructed to evaluate the associations of exercise with cancer mortality after adjusting for potential confounders such as age, alcohol consumption and smoking status. RESULTS: During the follow-up period of 15.3 years (4,638,863 person-years), a total of 16,884 participants died. Both men and women who exercised showed approximately 30% decreased hazards of mortality, compared to those who did no exercise (hazard ratio (HR) 0.70, 95% confidence interval (CI)=0.68-0.73 for men, HR=0.71, CI : 0.67-0.75). A notable observation of this study is the curvilinear associations between the total duration of exercise per week and cancer mortality, with the lowest risk being observed at the low-to-medium levels of exercise; this trend of associations was found for esophagus, liver, lung, and colorectal cancer mortality in men, and all-cause, all-cancer and lung cancer mortality in women. CONCLUSIONS: Individuals who exercised showed considerably lower all-cause and cancer mortality risks compared with those who did no exercise. Policies and clinical trials aimed at promoting minimal or moderate participation in exercise may minimize cancer mortality risk

Exercise and incidence of myocardial infarction, stroke, hypertension, type 2 diabetes and site-specific cancers: prospective cohort study of 257 854 adults in South Korea.

OBJECTIVE: The objective of this study was to examine the longitudinal associations of exercise frequency with the incidence of myocardial infarction, stroke, hypertension, type 2 diabetes and 10 different cancer outcomes. DESIGN: A prospective cohort study. SETTING: Physical examination data linked with the entire South Korean population's health insurance system: from 2002 to 2015. PARTICIPANTS: 257 854 South Korean adults who provided up to 7 repeat measures of exercise (defined as exercises causing sweat) and confounders. PRIMARY OUTCOME MEASURES: Each disease incidence was defined using both fatal and non-fatal health records (a median follow-up period of 13 years). RESULTS: Compared with no exercise category, the middle categories of exercise frequency (3-4 or 5-6 times/week) showed the lowest risk of myocardial infarction (HR 0.79; 95% CI 0.70 to 0.90), stroke (HR 0.80; 95% CI 0.73 to 0.89), hypertension (HR 0.86; 95% CI 0.85 to 0.88), type 2 diabetes (HR 0.87; 95% CI 0.84 to 0.89), stomach (HR 0.87; 95% CI 0.79 to 0.96), lung (HR 0.80; 95% CI 0.71 to 0.91), liver (HR 0.85; 95% CI 0.75 to 0.98) and head and neck cancers (HR 0.76; 95% CI 0.63 to 0.93; for 1-2 times/week), exhibiting J-shaped associations. There was, in general, little evidence of effect modification by body mass index, smoking, alcohol consumption, family history of disease and sex in these associations. CONCLUSIONS: Moderate levels of sweat-inducing exercise showed the lowest risk of myocardial infarction, stroke, hypertension, type 2 diabetes, stomach, lung, liver and head and neck cancers. Public health and lifestyle interventions should, therefore, promote moderate levels of sweat-causing exercise as a behavioural prevention strategy for non-communicable diseases in a wider population of East Asians.This work was supported by the National R&D Program for Cancer Control, Ministry of Health & Welfare, Republic of Korea (Grant 1631020 to SHJ), The Korean Health Technology R&D Project, Ministry of Health & Welfare, Republic of Korea (Grant HI14C2686 to SHJ) and the Medical Research Council (Grant MC_UU_12015/1 to SS). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript

Tracking Energy Balance in Adolescents: Levels of Compliance, Energy Flux, and Learning

Background/Objective: Advancing knowledge about energy balance (EB) is important for helping to reverse the obesity epidemic in many modern societies. This study examined adolescents\u27 experience and perception of using an objective self-monitoring tool (SenseWear armband; SWA) and a portable diet journal to track EB for 7 days. Methods: Forty-five 6th grade students in a midwestern state of the United States [Caucasian: n = 34, 76%; age: 11.7 ± 1.8 years; body mass index (BMI): 20.84 ± 3.94] participated in the study. The SWA, diet journal, and semistructured individual interview were used to measure energy expenditure (EE) and physical activity (PA), energy intake (EI), and perception of the experience, respectively. Mixed methods were used to analyze quantitative and qualitative data. Results: It was found that the participants were physically active over the week (moderate-to-vigorous PA: 218.06 ± 26.50 minutes per day). Both SWA (% of wearing time: 85 ± 5%) and diet journal (days of using: 5.58 ± 2.15 days), especially the latter, were found to be under-used. A conceptual model depicting the adolescents\u27 experience and perception was established based on the results. Conclusion: The study indicates that the majority of adolescents were able to effectively use the SWA and the diet journal to track EB over time. Qualitative observations revealed that tracking EI and EE with these tools provided a valuable, experiential way for youth to learn about EB. The findings support the continued exploration of self-monitoring EB for promoting knowledge and awareness about EB among adolescents