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The purpose of this study is to examine the change in physical activity levels among children and adolescents living in the area affected by the 2011 earthquake and tsunami for 3 years immediately following the disaster. Children and adolescents graded four to nine and attending school in the Pacific coastal area of northern Japan were included in a total of four serial prevalence investigations: the first at 6 months after the earthquake/tsunami (I, n = 434) and additional surveys at 1 year (II, n = 437), 2 years (III, n = 401), and 3 years (IV, n = 365) after the earthquake. Students were also required to undergo assessment of their accelerometer-determined daily steps and sedentary time using a self-administrated questionnaire. Accelerometer-determined median daily steps of children and adolescents were significantly different (p < 0.05) on both weekdays and weekends over 3 years. The median daily steps of children of both genders on weekdays and those of girls on weekends at period IV were significantly lower than those at period I. In addition, the median daily steps of adolescents on weekdays among girls and weekends among boys at period IV were significantly lower than those at period I. It appears that children and adolescents who survive the earthquake and tsunami experience a decrease in physical activity levels. Future research should elucidate longitudinal demographic and sociocultural factors that contribute to changes in physical activity levels among children and adolescents living in the areas affected by these disasters.

Background An assessment of the adverse health effects of obesity in children with Down's syndrome (DS) is required to develop programs that facilitate the acquisition of healthy behaviors. Individuals with DS are often obese. These individuals must develop health related behaviors in childhood. For this reason, it is necessary to clarify the factors associated with obesity in children with DS. Aims This study had two purposes. The first was to assess the obesity and to evaluate the sedentary behavior (SB) and physical activity of Japanese elementary school children with Down's syndrome. The second was to investigate the association between obesity and SB or moderate to vigorous physical activity (MVPA). Methods and procedures Ninety-three children (male/female: 51/42) with DS in elementary school grades 1 to 6 (aged 7–12 years) participated in this study in Japan. Physical characteristics were obtained from the questionnaire completed by their parents. The questionnaire provided information on regular school checkups. SB and MVPA were evaluated using a triaxial accelerometer. Results Approximately 20% of the children with DS were obese. Nearly half of the children with DS achieved 60 min of MVPA. SB time was significantly longer in the upper grades (aged 11–12 years) than in the lower grades (aged 7–8 years). Comparing weekdays and weekend days, the middle (aged 9–10 years) and upper grades had significantly shorter MVPA times on weekend days. The frequency of obesity was significantly associated with shorter MVPA times in the lower grades and longer SB time in the middle grades. Conclusions and implications Children with DS may increase their SB time as their age group (grade category) increases. Increasing opportunities for MVPA during weekends may increase physical activity. The observed relationship between obesity and SB time or MVPA time may apply only to younger and middle grade children with DS. Further investigation is necessary to confirm these relationships.

This study aimed to annually examine anthropometric characteristics and physical activity (PA) among children transitioning from fourth grade (9–10 years of age) to eighth grade (13–14 years of age) in Japan. The participants’ (n = 63) age, grade, sex, weight, height, and weight status were recorded at baseline. Accelerometry assessments were performed annually following established protocols. Time spent on activities requiring ≥ 3 metabolic equivalents (METs), 1.6–2.9 METs, and ≤ 1.5 METs were defined as moderate-to-vigorous intensity PA (MVPA), light PA (LPA), and sedentary behavior (SB), respectively. Two linear mixed models were used to examine whether MVPA, LPA, and SB min/day changed over time. Fifty-five participants provided complete data. A significant, nonlinear, longitudinal decline in MVPA, an increase in SB, and a linear decline in LPA were observed. Changes in MVPA and SB were accelerated in seventh grade (12–13 years of age). Male sex and maintenance of normal weight status were associated with higher MVPA levels. Changes in LPA and SB were not associated with sex or weight status. During the transition period from primary to secondary school, MVPA and SB showed nonlinear accelerations. Sex and normal weight were associated with more time spent performing MVPA.

Children with Down syndrome (DS) have physical characteristics such as hypotonus of the musculature. Therefore, their attainment rate of physical activity guidelines is low, and guidelines alone may not be sufficient in assessing the amount of physical activity in children with DS. Compared with normal children (NC) of the same grade, light physical activity (LPA) must be considered while assessing physical activity of children with DS, owing to muscle hypotonia. This study included 69 children with DS and 68 NC in grades 4–6 attending elementary school in Japan. The measurements for physical characteristics included age, height, weight, and body mass index. Physical activity was measured using a triaxial accelerometer, which indicated physical activity volume. Children with DS had less moderate-to-vigorous physical activity duration (DS: 53.1 min/day, NC: 65.0 min/day; p < 0.001) but significantly longer LPA duration (DS: 376.4 min/day, NC: 287.7 min/day; p < 0.001) than NC. Conversely, the amount of light to vigorous physical activity (Met’s-hours/day) was greater in children with DS (DS: 16.0 Met’s-hours/day, NC: 14.4 Met’s-hours/day; p = 0.037). In children with DS with muscular hypotonia, vigorous physical activity is challenging, but LPA is feasible. Developing and validating educational programs that promote physical activity with intensity level depending on individual’s physical characteristic are warranted.

Background: Iron deficiency anemia (IDA) is a public health problem in children and adolescents that is characterized by reduced hemoglobin (Hb) levels. Non-invasive monitoring devices can measure Hb levels continuously without pain or discomfort; however, little is known about their accuracy in children and adolescents. This study estimated the accuracy of a non-invasive Hb monitor in this age group. Methods: Participants were outpatients visiting the Tokyo Metropolitan Children's Medical Center for blood tests between January and March 2019. Hb levels were measured using both non-invasive Astrim Fit monitoring devices and invasive blood collection followed by automated analysis. BlandeAltman analysis assessed the agreement between the two measurements. Results: Overall, 120 schoolchildren (9e15 years old, 51 % female) were enrolled. The noninvasive measuring device recorded Hb levels of 13.5 AE 1.6 g/dL (mean AE standard deviation [SD]), while the mean Hb level obtained from the collected blood was 13.7 AE 1.7 g/dL. Therefore, the mean difference of bias and SD of precision was 0.17 AE 1.95 g/dL. Values of lower and upper limits of agreement were À3.65 and 3.99, respectively. There was no systematic fixed or proportion bias. Fifty-nine participants (49 %) had a relative error of AE 0.10. Conclusion:The Astrim Fit non-invasive Hb monitor can be used to evaluate Hb levels among schoolchildren for health promotion or research purposes because of its extremely low bias (or precision), no systematic biases (including fixed or proportion biases), and positive correlation between non-invasive monitoring and blood drawing. However, it is difficult to assess Hb levels in children and adolescents using the Astrim Fit device for diagnostic purposes.

The study aimed to assess a self-reported questionnaire about physical activity (PA) from the Health Behaviour in School-aged Children (HBSC) using triaxial accelerometer as a criterion. Elementary school boys (N=292) and girls (N=313) in the fourth grade and higher completed the questionnaire and wore an accelerometer for at least 10 h/day for at least 4 days. The phi coefficients of the chi-square test 2-way tables (active/inactive as measured using the HBSC questionnaire × achievement/non-achievement of the recommended 60-min moderate to vigorous PA [MVPA] as measured using the accelerometer) were 0.25 (P<0.001), 0.17 (P=0.009), and 0.08 (P=0.217) for all children, boys, and girls, respectively. The sensitivity and specificity in boys were 82% (95% confidence interval [CI]=78-86%) and 34% (95% CI=26-41%) respectively, while the those of girls were 52% (95% CI=40-63%), 57% (95% CI=55-60%). The positive predictive value in boys was 70% (95% CI=66-73%) and negative predictive value in girls was 83% (95% CI=79-87%). The independent t-test showed that moderate PA (MPA), vigorous PA (VPA), and MVPA min/day of active children were significantly higher than those of inactive children (range of Cohen's d=0.38 to 0.71). Area under the curve (AUC) of the VPA (AUC = 0.60-0.73) in girls was significantly higher than that of the MPA (AUC = 0.52-0.65) and MVPA (AUC = 0.54-0.67). Our results supported that the HBSC self-reported questionnaire has acceptable, but limited agreement for assessing achievement/non-achievement of the MVPA recommendation, and could estimate the differences in the MPA, VPA, and MVPA min/day of children.

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