Association between Chronic Mental Stress and Academic Performance among Korean Adolescents / Asociación entre estrés mental crónico y desempeño académico en adolescentes koreanos

En este estudio se examinó si el estrés mental crónico se asocia con el rendimiento académico en adolescentes coreanos. La muestra estuvo constituida por los 74.186 adolescentes de entre el 7 y el 12 ° grado (12-18 años) que participaron en la 8va encuesta en internet sobre Comportamiento de Riesgo en Jóvenes en 2012. Se utilizó el análisis de regresión logística multivariante para aclarar cómo el estrés crónico mental se relacionaba con el rendimiento académico después del ajuste por edad, índice de masa corporal, posición económica de la familia, el nivel de educación de los padres, la frecuencia de fumar, la frecuencia de ingesta de alcohol, y la frecuencia de la actividad física vigorosa y moderada y ejercicios de fuerza musculares. Para los varones, las personas con estrés mental crónico muy alto tenían menos probabilidades de lograr un rendimiento académico promedio o superior (odds ratio [OR] = 0.738, 95% intervalo de confianza [IC]: 0.629 a 0.867, p <0,001) que aquellos con muy estrés mental baja. Para las niñas, las que tenían estrés mental muy alto tenían menos probabilidades (OR = 0.668; IC del 95%: 0.521 - 0.857, p = 0.002), mientras que aquellas con estrés mental bajo tenían más probabilidades (OR IC = 1.324, 95%: 1.029 -1.704; p = 0.029) para tener un rendimiento promedio académico o superior, en comparación con las niñas con estrés muy bajo. Los grados (pruebas, exámenes de ingreso) fueron la principal causa de estrés mental crónico tanto en varones (51.7%) y niñas (54.,8%). Los varones y las niñas de la República de Corea de estrés mental crónico muy alto mostraron una disminución del rendimiento académico.

We examined whether chronic mental stress is associated with academic performance in Korean adolescents. Our sample consisted of the 74,186 adolescents between the 7th and 12th grades (aged 12-18 years) who participated in the 8th Korean Youth Risk Behavior Web-based Survey in 2012. We used multivariate logistic regression analysis to clarify how chronic mental stress was related to academic performance after adjustment for age, body mass index, family economic status, parents' education level, smoking frequency, alcohol intake frequency, and frequency of vigorous and moderate physical activity and muscular strength exercises. For boys, those with very high chronic mental stress were less likely to achieve average academic performance or higher (odds ratio [OR] = 0.738, 95% confidence interval [CI]: 0.629-0.867, p < 0.001) than were those with very low mental stress. For girls, those with very high mental stress were less likely (OR = 0.668, 95% CI: 0.521-0.857, p = 0.002), while those with low mental stress were more likely (OR = 1.324, 95% CI: 1.029-1.704; p = 0.029) to have average academic performance or hig-her, compared with girls with very low stress. Grades (tests, entrance examinations) were the primary cause of chronic mental stress in both boys (51.7%) and girls (54.8%). Republic of Korean boys and girls with very high chronic mental stress showed decreased academic performance.

Analysis of range of motion and isokinetic strength of internal and external rotation according to humeral retroversion of the dominant shoulder in youth baseball players: a pilot study

Background: We aimed to analyze the range of motion [ROM] and internal rotation [IR] and external rotation [ER] isokinetic strength according to humeral retroversion of the dominant shoulder

Methods: We included 40 elite baseball players in Korea [OBP group: n=20 players with careers spanning >10 years, age: 19.37+/-2.21 years, height: 181.00+/-5.41 cm, weight: 84.58+/-7.85 kg; BBP group: n=20 players with careers spanning <10 years, age: 16.55+/-1.36 years, height: 177.27+/-7.57 cm, weight: 77.27+/-8.14 kg]. Radiography was performed to examine humeral retroversion, a goniometer was used to measure IROM and EROM, and a dynamometer was used to measure IR and ER isokinetic strength [speed set at 180°/s or 300°/s]

Results: The BBP and OBP groups had significantly different IR and ER isokinetic strength [180°/s and 300°/s] [P<0.001] and dominant shoulder retroversion [P=0.009]. In the BBP group, retroversion had no correlation with ROM and with IR or ER isokinetic strength [180°/s and 300°/s]. In the OBP group, retroversion had no correlation with ROM and with ER isokinetic strength at 180°/s, but had significant correlation with IR isokinetic strength at both 180°/s [r=0.483, P=0.007] and 300°/s [r=0.373, P=0.043] and ER isokinetic strength at 300°/s [r=0.366, P=0.046]

Conclusion: Thus, youth players with careers spanning >10 years had significantly higher humeral retroversion, IROM, EROM, and IR and ER isokinetic strength of the dominant shoulder than youth players with careers spanning <10 years. Furthermore, humeral retroversion and ROM were not significantly related, but IR and ER isokinetic strength were significantly positively related with retroversion in both groups

The Effect Size Analysis of Exercise on Body Composition, Blood Pressure, and Physical Fitness in Korean Adults

BACKGROUND: The purpose of this study was to examine the effect size analysis of an exercise program on body composition, blood pressure, and physical fitness in Korean adults. METHODS: The subjects were 1,095 adults (men=76, women=1,019) older than 19 years who participated in the Fitness Promotion program at the centers for National Fitness Award Program in 2012. The subjects performed the regular combined exercise for 60-90 minutes per day, 2-4 days a week for 8 weeks. And the intensity of the exercise program was moderate (55-80% of maximum heart rate). In this study the effect size (ES) was calculated by the Cohen (1988) method. RESULTS: The ES was 0.06-0.11 (average small ES) for body composition, 0.52-0.77 (average large ES) for blood pressure, and 0.08-0.48 (average medium ES) for physical fitness variables. CONCLUSIONS: The estimated ES would be a useful reference to determine sample size for post-exercise experimental research.

The Effect Size Analysis of Exercise on Body Composition, Blood Pressure, and Physical Fitness in Korean Adults

BACKGROUND: The purpose of this study was to examine the effect size analysis of an exercise program on body composition, blood pressure, and physical fitness in Korean adults. METHODS: The subjects were 1,095 adults (men=76, women=1,019) older than 19 years who participated in the Fitness Promotion program at the centers for National Fitness Award Program in 2012. The subjects performed the regular combined exercise for 60-90 minutes per day, 2-4 days a week for 8 weeks. And the intensity of the exercise program was moderate (55-80% of maximum heart rate). In this study the effect size (ES) was calculated by the Cohen (1988) method. RESULTS: The ES was 0.06-0.11 (average small ES) for body composition, 0.52-0.77 (average large ES) for blood pressure, and 0.08-0.48 (average medium ES) for physical fitness variables. CONCLUSIONS: The estimated ES would be a useful reference to determine sample size for post-exercise experimental research.

The Effect Size Analysis of Exercise on Body Composition, Blood Pressure, and Physical Fitness in Korean Adults

BACKGROUND: The purpose of this study was to examine the effect size analysis of an exercise program on body composition, blood pressure, and physical fitness in Korean adults. METHODS: The subjects were 1,095 adults (men=76, women=1,019) older than 19 years who participated in the Fitness Promotion program at the centers for National Fitness Award Program in 2012. The subjects performed the regular combined exercise for 60-90 minutes per day, 2-4 days a week for 8 weeks. And the intensity of the exercise program was moderate (55-80% of maximum heart rate). In this study the effect size (ES) was calculated by the Cohen (1988) method. RESULTS: The ES was 0.06-0.11 (average small ES) for body composition, 0.52-0.77 (average large ES) for blood pressure, and 0.08-0.48 (average medium ES) for physical fitness variables. CONCLUSIONS: The estimated ES would be a useful reference to determine sample size for post-exercise experimental research.

Lifestyle factors and obesity among Korean adults

The purpose of this study was to examine whether lifestyle-related factors, such as frequency of drink-ing and smoking, mental stress, sleep duration, economic status, and education level, are associated with obesity [as defined given by the WHO report on Asia] in a selected sample of Korean adults. The subjects were 1,566 adults [505 men, 1,061 women] aged over 20 years who visited a public health center for medical checkups in Seoul, Korea, between November 1, 2010, and October 30, 2011. The association between lifestyle-related factors and obesity was assessed by using multivariate logistic regression analysis after adjusting for gender, age, frequency of drinking and smoking, mental stress, sleep duration, economic status, and education level. Only economic status and education level significantly predicted obesity; very rich people and people who completed high school, college, or higher were less likely to be obese. Therefore, frequency of smoking and drinking, sleep duration, and level of stress were not associated with obesity but economic status and educational level significantly predicted obesity

Association between frequency of breakfast consumption and academic performance in healthy Korean adolescents

The purpose of this study was to examine whether the frequency of breakfast consumption was related to academic performance in healthy Korean adolescents. We analyzed data from the seventh Korea Youth Risk Behavior Web-based Survey conducted in 2011, in which 75,643 adolescents from school grades 7-12 participated. We assessed the association between the frequency of breakfast consumption [per week] and academic performance using multivariate logistic regression analysis after adjusting for covariates such as age, body mass index, frequency of smoking, frequency of drinking, parents? education level, family economic status, frequency of vigorous physical activity[PA], frequency of moderate PA, frequency of muscular strength exercises, and level of mental stress. For male adolescents, the odds ratios[ORs] for achieving average or higher academic performance according to the breakfast frequency per week were once per week, 1.004[P=0.945]; twice per week, 0.915[P=0.153]; 3 days per week, 0.928[P=0.237]; 4 days per week, 1.087[P=0.176]; 5 days per week, 1.258[P<0.001]; 6 days per week, 1.473[P<0.001]; and every day, 1.700[P<0.001], compared to no breakfast per week. For female adolescents, the ORs for achieving average or higher academic performance according to the breakfast frequency were once per week, 1.068[P=0.320]; twice per week, 1.140[P=0.031]; 3 days per week, 1.179[P=0.004]; 4 days per week, 1.339[P<0.001]; 5 days per week, 1.449[P<0.001]; 6 days per week, 1.768[P<0.001]; and every day, 1.922[P<0.001], compared to no breakfast per week. The frequency of breakfast consumption is positively correlated with academic performance in both male and female healthy adolescents in Korea

Associations of hypertension status with physical fitness variables in korean women

In Korea, hypertension has become more prevalent with the Westernization of Korean diets and lack of exercise. This study aimed at investigating the associations between physical fitness variables and hypertension status in Korean women. The subjects were 9,216 women aged >20 years who visited a public health promotion center for physical fitness tests. Cardiovascular respiratory fitness was evaluated using VO[2]max, resting heart rate [RHR], double product [DP], and vital capacity and coordination-related physical fitness was measured using grip strength, number of sit-ups completed, sit-and-reach score, vertical jump height, number of side steps performed, and 1-leg standing with eyes open. The prevalence rates of prehypertension and hypertension were 30.3% and 12.9% in this study, respectively. After adjusting for age, body mass index, drinking frequency, smoking intensity, and exercise intensity, the odds ratios [95% confidence interval] were calculated, and no statistically significant association was found between hypertension and physical fitness as measured by grip strength [P = 0.056], number of sit-ups completed [P = 0.140], and vertical jump height [P = 0.121]. However, significant associations were found between hypertension and VO[2]max [P < 0.001], RHR [P< 0.001], DP [P < 0.001], vital capacity [P < 0.001], sit-and-reach score [P = 0.012], the number of side steps performed [P = 0.001], and 1-leg standing with eyes open [P < 0.001]. We found that all the cardiovascular respiratory fitness variables and half of the motor- and coordination-related physical fitness variables were closely related with hypertension status

Differences in lifestyles including physical activity according to sexual orientation among Korean adolescents

The purpose of the present study was to examine differences in lifestyle factors such as physical activity among homosexual [gay or lesbian], bisexual, and heterosexual Korean adolescents. The sample consisted of 74,186 adolescents from grades 7-12 [ages 12-18] who participated in the 8[th] annual Korea Youth Risk Behavior Web-based Survey in 2012. Of this sample, only 11,829 provided enough information regarding their romantic and sexual experiences to define them as gay, lesbian, bisexual, or heterosexual. From this information, males were divided into gay [n = 323], bisexual [n = 243], and heterosexual [n = 6,501] groups, and females were divided into lesbian [n = 208], bisexual [n = 113], and heterosexual [n = 4,441] groups. Differences in lifestyle factors according to sexual orientation were analyzed using one-way analysis of variance. Males showed significant differences by sexual orientation group in terms of frequency of smoking [P = 0.029], alcohol consumption [P < 0.001], muscular strength exercises [P = 0.020], and walking for at least 10 minutes per week [P < 0.001]. Females showed significant differences by sexual orientation group in terms of frequency of smoking [P < 0.001], alcohol consumption [P < 0.001], vigorous physical exercise [P < 0.001], moderate physical exercise [P < 0.001], and muscular strength exercises [P < 0.001], as well as for self-reported mental stress [P < 0.001]. We concluded those gay and bisexual males and lesbian and bisexual females had significant lifestyle differences as compared with heterosexual adolescents. This effect was stronger for females than for males

Association between frequency of breakfast eating and obesity in Korean adolescents

The purpose of this study was to examine whether the frequency of breakfast eating was related with overweight/obesity in Korean adolescents. We analyzed the data collected in the 5[th] KYRBWS, in which 72,399 adolescents participated in 2009. We assessed the association between frequency of breakfast eating and body mass index by using multivariate logistic regression analysis. A total of 20,962[54.9%] boys and 18,479[54.0%] girls skipped breakfast 7 days[all days] per week at baseline. For boys, the odds ratios[ORs] between being overweight and frequency of breakfast eating were 1.040 for 3-5 times per week, 1.092 for 1-2 time[s] per week, 1.059 for no breakfast per week, compared to 6-7 times per week[p>0.05]. The ORs between being obese and frequency of breakfast eating were 1.011 for 3-5 times per week, 0.968 for 1-2 time[s] per week, and 0.932 for no breakfast per week, compared to 6-7 times per week[p>0.05]. For girls, the ORs between being overweight and frequency of breakfast eating were 0.990 for 3-5 times per week, 0.992 for 1-2 time[s] per week, 1.019 for no breakfast per week, compared to 6-7 times per week[p>0.05]. The ORs between being obese and frequency of breakfast eating were 1.075 for 3-5 times per week, 0.946 for 1-2 time[s] per week, and 0.941 for no breakfast per week, compared to 6-7 times per week[p>0.05]. The frequency of breakfast eating has no correlation with overweight/obesity in Korean adolescents

Association between physical inactivity and academic record in korean adolescents

The purpose of this study was to investigate the association between physical inactivity and academic record in Korean adolescents. Adolescent students from the first grade of middle school to the third grade of high school [n=75,066] participated in the 5th Korea Youth Risk Behavior Web-based Survey project in 2009. The association between physical inactivity and academic record was assessed using multivariate logistic regression analysis after adjusting for gender, age, body mass index, family's socioeconomic status, parents' education level, and frequency of vigorous or moderate physical activity [PA] as well as muscular strength exercises. During weekdays, the odds ratios [Ors] [95% confidence interval [CI] for reporting a higher than average academic record, as compared with <1 hour of physical inactivity per day, was 0.796 [0.761-0.832, for >/= 1 to <2 hours, 0.632 [0.603-0.663, for >/= 2 to <3 hours, 0.567 [0.535-0.601 for >/= 3 to <4 hours, and 0.494 [0.468-0.522, P < 0.001 for all cases] for >/= 4 hours of physical inactivity per day. During the weekends, the ORs [95° o CI] for reporting a higher than average academic record, as compared with <1 hour of physical inactivity per day, were 0.901 [0.848-0.957, P = 0.001] for >/= 3 to <4 hours and 0.785 [0.743-0.830, P < 0.001] for >/= 4 hours of physical inactivity per day. Korean adolescents who spend more time engaged in physical inactivity are predisposed to a below-average academic record

Relationships between Body Mass Index and Social Support, Physical Activity, and Eating Habits in African American University Students

PURPOSE: We aimed to examine the relationships between obesity and the level of social support for healthy behaviors, amount of physical activity (PA), and dietary habits in African Americans. METHODS: The subjects were 412 university students who visited a health promotion center at North Carolina A&T State University, Greensboro, NC, USA between September 1, 2009 and April 30, 2010. We administered a social support survey, the National Institutes of Health Fruit, Vegetable, and Fat Screener, the Paffenbarger PA Questionnaire, and measures of body mass index, waist circumference (WC), and blood pressure. Data were analyzed using a one-way analysis of variance and logistic regression analyses. RESULTS: Results showed that men in the overweight group had WC and systolic blood pressure (SBP) measurements associated with increased risk of cardiovascular disease (CVD) and below average PA; those in the obese group had WC, SBP, and diastolic blood pressure (DBP) measurements associated with CVD risk and below average PA. Women in the overweight group had WC and SBP measurements associated with CVD risk, and those in the obesity group had WC, SBP, and DBP measurements associated with CVD risk and below average PA. Logistic regression analysis showed that increasing PA by 1,000 kcal/week decreased the prevalence of obesity by 9.3% in men and 9.0% in women. CONCLUSION: Thus, low PA was a significant risk factor for obesity among African Americans. However, the level of social support and consumption of fruits, vegetables, and fat were not found to be significant risk factors in this study.

Association between times spent on the internet and weight status in Korean adolescents

This study investigates whether the amount of time that Korean adolescents spend on the Internet per day is related to their weight status. For this purpose, we analyzed data from the 2009 Korea Youth Risk Behavior Web-based Survey-V [KYRBWSV], in which 72,399 students from the 7[th] to the 12[th] grade participated. We assessed the relationship between the amount of time spent on the Internet per day and body mass index [BMI] by using multivariate logistic regression analysis. For boys, the odds ratio [OR; confidence interval [CI]: 95%] between becoming overweight and the amount of time spent on the Internet per day was 1.225 [1.042-1.441; P=0.014] for >4 hour. The ORs [CI: 95%] between becoming obese and time spent on the Internet per day were 1.238 [1.096-1.399; P=0.001] for >2- 3- 4 hours. For girls, the ORs [CI: 95%] between becoming overweight and time spent on the Internet per day were 1.265 [1.089-1.469; P=0.002] for >2- 3- 2- 3-

Prevalence of obesity in adolescents with history of pregnancy and associated factors in Korea

The pregnancy was a risk factor for excessive gain for women. However, there is no information about the prevalence of obesity and its relationship with a history of pregnancy in girls. Therefore, the purpose of this study was to investigate differences in the prevalence of obesity in adolescent females with a history of pregnancy and factors associated with it, in Korea. In 2009, 69 of 34,247 female students revealed that they had experienced pregnancy in response to the 5[th] Korea Youth Risk Behavior Web-based Survey [KYRBWS-V] project by the Korea Centers for Disease Control and Prevention [KCDCP]. The body mass index [BMI] and experienced pregnancy categories of the KYRBWS-V were assessed, and, for data analysis, the independent t-test, chi-square test, and multivariate logistic regression were used. The risk of pregnancy was increased by approximately 47% per unit increase in age, and 331% per unit increase in depression, respectively. Conversely, the risk decreased by 19% per unit increase in BMI and 33% per unit increase [ranged from 1: very rich to 5: very poor] in the family economic state. Obesity in adolescent females is minimally affected by a history of pregnancy, if at all, despite the fact that pregnancy was risk factor for excessive weight gain in women. However, adolescent females with a history of pregnancy have higher levels of depression than do normal peers in Korea