The Association Of Sedentary Behavior And Physical Health In Preschoolers

Objective: The level of physical health development in preschool period is related to the health status of adulthood.At present,the research results of sedentary behavior and physical health development are not completely consistent,and the research population is mainly concentrated on children and adolescents;the studies carried out in preschoolers are very limited.Thus,the aim of this study is to explore the relationship between sedentary behavior and physical health in preschoolers.Methods: The data in this study is derived from baseline data of preschool children from two studies in 2013-2014 and 2018.Two studies recruited a total of 471 preschoolers from 9 kindergartens in Shanghai,who had normal intellectual development,no major mental illnesses,and could participate in moderate to highintensity physical activities.After data selected,a total of 375 preschoolers(211 males and 164 females,with an average age of 4.56 years)were included in the statistical analysis.Sedentary behavior(SB)and physical activity time were measured by Accelerometer.We set the sampling interval(epoch)as 1s,and the valid data were defined as including at least 3 days of sensor measurement data(2 working days + 1weekend day,wearing time ≥ 480 minutes/day).The cut point of SB was defined as <25counts/15 s,and SB included total SB time,SB Bouts time(SB with prolonged bouts≥ 180 epochs),and SB Breaks times(SB interruption times with duration ≥ 1 epoch)in study.The cut point of moderate to vigorous physical activity(MVPA)was defined as≥ 420counts/15 s.Physical health score is obtained by adding up the standardized score of five indexes: height and weight standard score,grip-strength,standing long jump,2×10 meters shuttle run and 20 meters shuttle-run test.The multiple linear regression model is used to explore the relationship between sedentary behavior and physical health score,and the Isotemporal substitution model was used to explore the change of physical health score when SB is substituted by other activities.Results: The total SB and SB Bouts time were negatively correlated with physical health score of preschoolers after adjusted for confounding factors.Physical health score decreased by 1.68 points(β=-1.68,95%CI=-2.75,-0.60)for per 10 min increased in total SB;The physical health score of highest quartile group children(623.80-838.97)decreased by 9.74 points(β=-9.74,95%CI=-18.42,-1.07,P for trend < 0.01)compared with the lowest quartile group(394.73-534.65).Similarly,Physical health score decreased by 0.69 points(β=-0.69,95%CI=-1.19,-0.19)for per 10 min increased in SB Bouts time,and the physical health score of highest quartile group(446.28-650.81)children decreased by 10.70 points(β=-10.70,95%CI=-19.29,-2.11,P for trend < 0.01)compared with the lowest quartile group(202.01-354.51).There was a positive correlation between the SB Breaks times and physical health score,physical health score increased by 0.09 points(β=0.09,95%CI=0.01,0.17)for per 10 times of SB Breaks times increased.The results of the Isotemporal substitution model showed that physical health score increased 16.57 points(β=16.57,95%CI=9.77,23.36)and 15.89points(β=15.89,95% CI=8.92,22.86)when the total SB and SB Bouts time were replaced by 30 minutes MVPA behavior significantly,after adjusted for confounding factors.Conclusions: There was a significant correlation between sedentary behavior and physical health of preschoolers.The total SB and SB Bouts time were negative correlated with physical health,but the SB Breaks times was positive correlated with physical health.Physical health score improved significantly when the total SB and SB Bouts time were replaced by moderate to vigorous physical activity.we should try to decrease the sedentary behavior time and increase the SB Breaks times of preschools to promote their good physical development.