All retinas are not created equal: Fovea-to-macula thickness ratio and foveal microvasculature in healthy young children.

PURPOSE: Markers for the relationships between structural and microvasculature measures given by optical coherence tomography angiography are necessary to increase the diagnostic and prognostic value of this technique. The aim of this study was to investigate relationships between structural and microvasculature measures around the fovea in healthy eyes of healthy children. METHODS: Observational cross-sectional study involving children aged 8-17 years, born at full-term, with no eye disease. The better of two 3 × 3 mm macular scans obtained with a Cirrus 5000HD-OCT was analysed. Images were corrected for lateral magnification errors. Vessel density and perfusion were measured with ImageJ/Fiji software for the superficial capillary plexus. Structural measures including foveal and macular thicknesses were performed manually. RESULTS: The sample included 86 participants, 51 (59%) females. Mean age was 12.4 years (SD = 2.5); mean best-corrected acuity was -0.10 logMAR (SD = 0.09); mean refractive error was +0.59 D (SD = 1.3) and mean axial length was 23.1 mm (SD = 0.86). Mean area of the foveal avascular zone (AFAZ) was 0.20 mm2 (SD = 0.88); median fovea-to-macula thickness ratio (FMTR) was 0.63 (IQR = 0.08); mean central vessel density was 12.42 mm-1 (SD = 2.78) and mean central perfusion was 38.66% (SD = 3.83). AFAZ was correlated with central vessel density (p < 0.001), perfusion (p < 0.001), foveal thickness (p < 0.001) and FMTR (p < 0.001). Central vessel density was correlated with foveal thickness (p < 0.001) and FMTR, (p = 0.01). Central perfusion was correlated with foveal thickness (p < 0.001) and FMTR, (p = 0.003). CONCLUSION: In this study, foveal thickness, FMTR and foveal microvasculature measurements were correlated. Clinicians need to be aware that shallow foveal pits and persistent foveal microvasculature are likely to occur in optical coherence tomography angiography images. In healthy eyes from healthy children, an atypical high FMTR and a small AFAZ may be associated with incomplete foveal development. The mechanism and functional implications of this remain unknown.

Pupils' use of school outdoor play settings across seasons and its relation to sun exposure and physical activity.

BACKGROUND: Long outdoor stay may cause hazardous exposure to ultraviolet radiation (UVR) from the sun even at high latitudes as in Sweden (Spring to Autumn). On the other hand, long outdoor stay is a strong predictor of primary school children´s free mobility involving moderate to vigorous physical activity (MVPA). UV-protective outdoor environments enable long outdoor stay. We investigated the concurrent impact of different school outdoor play settings upon pupils´ sun exposure and levels of physical activity across different ages, genders, and seasons. METHOD: During 1 week each in September, March, and May, UVR exposure and MVPA were measured in pupils aged 7-11 years. Erythemally effective UVR exposure was measured by polysulphone film dosimeters and MVPA by accelerometers. Schoolyard play was recorded on maps, and used areas defined as four play settings (fixed play equipment, paved surfaces, sport fields, and green settings), categorized by season and gender. RESULTS: During the academic year, sport fields yielded the highest UVR exposures and generated most time in MVPA. In March, time outdoors and minutes in MVPA dropped and UVR exposures were suberythemal at all play settings. In May, green settings and fixed play equipment close to greenery promoted MVPA and protected from solar overexposure during long outdoor stays. CONCLUSION: More outdoor activities in early spring are recommended. In May, greenery attractive for play could protect against overexposure to UVR and stimulate both girls and boys to vigorous play.

Solar Ultraviolet Radiation Exposure Proxy-estimated by Sky View Fish-eye Photography-Potentials and Limitations from an Exploratory Correlation Study.

Potentials and limitations of sky view fish-eye photography and calculation of the percentage of free sky (sky view factor, SVF) as a proxy to estimate solar ultraviolet radiation (UVR) exposure in shade settings are investigated using controlled situations. SVF and measured solar UVR exposure correlated at high mid-latitude (56.65°N) near autumnal equinox in September. The correlation was enhanced by splitting the sky view images into a south- and a north-half and weighting the south-half higher to account for the direct sun. Sky view images from eight different settings with SVF-values 98.3% - 14.9% were compared to exposure measurements by polysulphone film dosimeter badges in the horizontal zenith-, vertical-south-, east-, west- and north-directions and their combinations. The sky view images were un-split and un-weighted or split and the semi-skies given south/north weights (3.0/1.0) or a higher weight ratio (3.5/0.5). Of all tested combinations split sky view SVFs weighted 3.0/1.0 and compared to horizontal (zenith-oriented) dosimeters yielded the highest correlation (R2  = 0.96). The weight ratio (3.5/0.5) yielded the 2nd highest correlation (R2  = 0.90) both compared to measured horizontal exposure and compared to the horizontal exposure averaged with the vertical-south-oriented exposure. SVF from sky view fish-eye photography may estimate solar UVR exposure in shade settings.

Levels of physical activity during physical education lessons in Sweden.

AIM: The aim of this study was to measure the percentage of sedentary light and moderate-to-vigorous physical activity (%MVPA) provided by physical education (PE) lessons for Swedish second, fifth and eighth grade students, aged eight, 11 and 14. METHODS: We observed 39 PE lessons and divided them into seven lesson categories: ball play, ball games, dance, fitness, playing games, orienteering and gymnastics. Physical activity (PA) during PE was estimated using accelerometers and the height and weight of the children were measured. RESULTS: We studied 149 children: 63 in the second grade, 66 in the fifth grade and 19 in the eighth grade. On average, 25% of the PE lessons were spent in MVPA and the mean %MVPA varied with the lesson content, with fitness, orienteering and playing games being the most intense. The highest %MVPA was in the fitness category, providing 33% (8-62%) for girls and 37% (7-72%) for boys. With the exception of the second grade, no significant gender differences in %MVPA were seen. CONCLUSION: The content of Swedish PE lessons affected the %MVPA in all age groups. In some content, individuals reached two-thirds of their daily PA recommendations, highlighting the potential that PE contributes to public health goals.

Compulsory School In- and Outdoors-Implications for School Children's Physical Activity and Health during One Academic Year.

Regulated school days entail less free-living physical activity (PA) and outdoor stay, which may jeopardize the opportunities for cohesive moderate-to-vigorous physical activity (MVPA) and, by extension, children's health. The role of outdoor stay during school time for pupils' free-living PA vs. physical education (PE) and indoor stay was studied during one academic year in 196 pupils aged 7-14 years at four schools in mid-southern Sweden during five consecutive days each in September, March, and May. Actigraph GT3X+ Activity monitors were used. Predictors for PA during school stay were expressed as mean daily accelerometer counts and were measured per season, day, grade, gender, weather, and time outdoors. Overall, free-living PA outdoors generated the highest mean accelerometer counts for moderate and vigorous PA. Outdoor PA and PE, representing 23.7% of the total school time contributed to 50.4% of total mean accelerometer counts, and were the greatest contributors to moderate and vigorous PA. Age and weather impacted PA, with less PA in inclement weather and among older pupils. More time outdoors, at all seasons, would favorably increase school children's chances of reaching recommended levels of PA.

Suberythemal Sun Exposures at Swedish Schools Depend on Sky Views of the Outdoor Environments - Possible Implications for Pupils' Health.

More scheduled outdoor stay is increasingly advocated for school children. This study measured 2(nd) , 5(th) and 8(th) graders' erythemal UV-exposure in September, March and May at four Swedish schools. We related those exposures, as fractions of total available ambient radiation, to the schools outdoor environments differing in amount of shade, vegetation, and peripheral city-scape quantified as percentage of free sky view calculated from fish-eye photographs. Exposures correlated with the sky views (with exceptions in May) and were suberythemal. The exposures were also below the threshold limit of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) for hazard evaluation of UVR but were potentially enough for adequate vitamin D formation according to a cited model calculation - as illustrated in the results and discussed. The school environments, typical in southern and middle Sweden, offer enough shade to protect children from overexposure during seasons with potentially harmful solar UV radiation. Pupils' outdoor stay may be extended during September and March. In May extended outdoor stay of the youngest pupils requires a more UVR-protective environment.

Physical activity decreased by a quarter in the 11- to 12-year-old Swedish boys between 2000 and 2013 but was stable in girls: a smartphone effect?

AIM: This study explored physical activity, body mass index (BMI) and overweight and obesity from 2000 to 2013 using a convenience sample of second- and fifth-grade Swedish schoolchildren aged 8-9 years and 11-12 years, respectively. METHODS: We examined cross-sectional cohorts of 126 second-grade children in 2000, 84 in 2006 and 44 in 2013 and 105 fifth-grade children in 2000 and 38 in 2013. No fifth graders were available in 2006. Physical activity data were collected based on pedometer readings over four consecutive weekdays, and height and weight were measured. Identical instruments and procedures were used in all three years. RESULTS: There was an increase in physical activity in second-grade girls from 2000 to 2006 (p < 0.01), which then stabilised between 2006 and 2013, but second-grade boys and fifth-grade girls were stable throughout the study period. Fifth-grade boys decreased significantly (24%) from 16 670 to 12 704 steps per day (p < 0.01) from 2000 to 2013. Mean BMI scores remained stable over time. CONCLUSION: Time trends in physical activity differed between boys and girls. Second-grade boys and fifth-grade girls were stable throughout, whereas second-grade girls increased from 2000 to 2006 before stabilising. Fifth-grade boys showed a significant 24% reduction from 2000 to 2013. Changes in recess and leisure time habits, such as smartphone use, may have influenced the result.

A repeated measurement study investigating the impact of school outdoor environment upon physical activity across ages and seasons in Swedish second, fifth and eighth graders.

BACKGROUND: School children are confined to and exposed to outdoor environment that happens to be at their disposal during compulsory school time. The health-promoting potential of outdoor environment, and the use of it, is therefore important. We have studied the impact of school outdoor environment in terms of playground features, space, topography and vegetation upon the patterns of moderate to vigorous physical activity (MVPA) across ages and seasons in Swedish pupils at compulsory school. METHODS: Four schools in the Middle and Southern parts of Sweden, with outdoor environments differing in playground features, space, topography and vegetation were analyzed during one school year. A sample of 196 children was drawn from eligible pupils in grades 2, 5 and 8, aged 7-14 years. PA was monitored with time-stamped Actigraph accelerometers GT3X+, measuring different intensity levels during outdoor time. Maps were used to mark places where the children stayed and what they did during outdoor time. RESULTS: Mean MVPA during outdoor stay was 39 minutes for the entire school year, time in MVPA correlated positively with outdoor time, as did MVPA with used outdoor play area (p < 0.001). Outdoor MVPA declined with age, boys accumulated more MVPA than girls at all ages (p < 0.001). Ball play areas increased MVPA in 5th graders in September and May (p < 0.001). Overall, ball play areas increased 5th graders' relative MVPA, and helped maintaining it with increasing age in boys but not in girls, whereas woodland stimulated and contributed to maintaining girls' MVPA with increasing age. Outdoor temperature significantly impacted (p < 0.01) MVPA throughout all seasons. CONCLUSION: We conclude that school outdoor environment design and outdoor play time impact physical activity on a daily basis and may contribute to increasing girls' physical activity and moderate the sharp decline in physical activity by age. The school outdoor environment may thus be a potential health promoter during school time.

Influence of moderate, daily physical activity on body composition and blood lipid profile in Swedish adults.

BACKGROUND: Health organizations suggest that adults ought to engage in at least 30 minutes of moderate-intensity daily physical activity. This study investigated the effects of a 30-minute single daily bout of brisk walking upon risk factors for coronary heart disease with blood lipid profile in particular. METHODS: Thirty-three (25-45 y) adults, were randomly assigned into an exercise group (EG; n=16, 9w) and a control group (CG; n=17, 6w). The EG walked briskly 30 minutes daily during the 3-week test period. Compliance/adherence was maximal throughout the 3-week intervention due to stringent daily monitoring. RESULTS: The EG showed a significant decrease in concentrations of low density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) during the intervention period. A significant inverse correlation between Δ energy expenditure/day and ΔLDL-C (r=-0.39, P<.05) and an improvement in weight and BMI in the EG was found. Average steps during 30 minutes brisk walking bout was 3669 steps/bout generating a mean energy expenditure of 191 kcal/ bout. CONCLUSIONS: The most unique findings were that daily single bouts of moderate-intensity physical activity for 30 minutes, during 3 weeks, induced favorable effects upon body weight, BMI, and blood concentration of LDL-C and TC in healthy adults.

Accelerometer measured level of physical activity indoors and outdoors during preschool time in Sweden and the United States.

BACKGROUND: It is important to understand the correlates of physical activity (PA) to influence policy and create environments that promote PA among preschool children. We compared preschoolers' PA in Swedish and in US settings and objectively examined differences boys' and girls' indoor and outdoor PA regarding different intensity levels and sedentary behavior. METHODS: Accelerometer determined PA in 50 children with mean age 52 months, (range 40-67) was recorded during preschool time for 5 consecutive weekdays at 4 sites. The children wore an Actigraph GTIM Monitor. RESULTS: Raleigh preschool children, opposite to Malmö preschoolers spent significantly more time indoors than outdoors (P<.001). Significantly more moderate-to-vigorous intensity physical activity (MVPA) was observed outdoors (P<.001) in both settings. Malmö children accumulated significantly more counts/min indoors (P<.001). The percent of MVPA during outdoor time did not differ between children at Raleigh and Malmö. CONCLUSION: Physical activity counts/minutes was significantly higher outdoors vs. indoors in both Malmö and Raleigh. Malmö preschoolers spent 47% of attendance time outdoors compared with 18% for Raleigh preschoolers which could have influenced the difference in preschool activity between the 2 countries. Time spent in MVPA at preschool was very limited and predominantly adopted outdoors.

Comparison of pedometer and accelerometer measures of physical activity during preschool time on 3- to 5-year-old children.

AIMS: To compare pedometer steps with accelerometer counts and to analyse minutes of engagement in light, moderate and vigorous physical activity in 3- to 5-year-old children during preschool time. METHODS: Physical activity was recorded during preschool time for five consecutive days in 55 three- to five-year-old children. The children wore a Yamax SW200 pedometer and an Actigraph GTIM Monitor. RESULTS: The average time spent at preschool was 7.22 h/day with an average step of 7313 (±3042). Steps during preschool time increased with increasing age. The overall correlation between mean step counts and mean accelerometer counts (r = 0.67, p < 0.001), as well as time in light to vigorous activity (r = 0.76, p < 0.001), were moderately high. Step counts and moderate to vigorous physical activity minutes were poorly correlated in 3 years old (r = 0.19, p < 0.191) and moderately correlated (r = 0.50, p < 0.001) for children 4 to 5 years old. CONCLUSION: Correlation between the preschool children's pedometer-determined step counts and total engagement in physical activity during preschool time was moderately high. Children's step counts at preschool were low, and the time spent in moderate and vigorous physical activity at preschool was very short.