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Objective@#To explore the longitudinal association of the levels of plasma irisin among children with changes in obesity related parameters and newly onset obesity, and to explore whether physical activity (PA) and sedentary behavior(SB) have regulatory effects, to provide a scientific basis for the prevention and control of childhood obesity work.@*Methods@#Cluster random sampling method was used to select 521 children from five schools in Guangzhou in 2017 at baseline and were followed up in 2019. A based on baseline PA and SB, children who meet the following criterion were selected:moderate vigorous intensity PA≥60 min/d or <150 min/week; and gender , age specific SB≥ P 75 or SB < P 25 . Plasma irisin concentration was measured in all the selected children. Multiple linear regression and Logistic regression were conducted to analyze the association.@*Results@#The two year cumulative incidence of obesity, overweight and obesity, and central obesity was 2.82%, 6.57%, and 6.81%, respectively. There was no statistically significant association between plasma irisin levels and changes in obesity related parameters, newly onset overweight obesity or central obesity among children ( P >0.05). After stratified by PA, the irisin concentration in the low PA group was positively associated with weight change ( B=0.229, P =0.03). After stratified by SB, the irisin concentration in the low SB group was positively associated with the height change ( B=0.210, P <0.05). In addition, PA level and SB level both had a moderating effect on the association between plasma irisin levels and the weight change ( P PA=0.01, P SB =0.05).@*Conclusion@#PA and SB show moderating effect on plasma irisin concentration and weight gain. No association of irisin concentration with newly onset overweight or obesity among children has been found.
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Objective@#To examine the association of sedentary behaviors with visual acuity among primary school children, and to provide a reference basis for the prevention and control of poor vision.@*Methods@#Using stratified random cluster sampling method, a total of 4 969 students in grade 1-4 were selected from 5 primary schools in Guangzhou in 2017, and then were followed up in 2019. A validated questionnaire was used to collect data on children s sedentary behaviors, including doing homework, watching TV, playing computer/video games, and taking the bus/car between home and school. Visual acuity was measured in the baseline and the follow up using a 5 m standard logarithmic visual acuity chart. Multiple linear regression and Logistic regression were conducted to analyze the relationship between sedentary behaviors and visual changes.@*Results@#The two year cumulative incidence of poor vision was 48.74%. Homework time was inversely associated with visual acuity of left eye( β=-0.012, 95%CI =-0.023- -0.002 ). Homework time was positively correlated with poor vision( OR =1.16, 95% CI =1.05-1.27). However, total sedentary time, screen time and bus/car time were not statistically associated with changes in visual acuity( P >0.05).@*Conclusion@#Increased homework time was associated with poorer vision in primary school students. Interventions to reduce the academic burden should be taken.
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Objective To establish an HPLC method for simultaneous assay of macrocyclic polyphenols from Penthorum chinense Pursh, pinocembrin-7-O-[4'', 6''-(S)-hexahydroxydiphenoyl]-β-D-glucose (PHG), pinocembrin-7-O-[3''-O-galloyl-4'', 6''-(S)-hexahydroxydiphenoyl]-β-D-glucose (PGHG) and pinocembrin dihydrochalcone-7-O-[3''-O-galloyl-4'', 6''-(S)-hexahydroxydiphenoyl]-β-D-glucoside or thonningianin A (THA), and optimize the extraction process. Methods The total extraction rate of PHG, PGHG, THA was used as an investigated index to analyze the extracts from Penthorum chinense Pursh. Orthogonal design was applied to evaluate solvent amount, extraction time, solvent concentration and extraction times as the influencing factors for the optimal extraction process of macrocyclic polyphenols from Penthorum chinense Pursh. Results When this content assay method was adopted, there were good linear relationships for PHG, PGHG, THA in the linear range. The recoveries were between 100.90% to 102.04% with the RSDs below 1.5%. The optimal extraction process was involved in cutting Penthorum chinense Pursh into 3-5 cm, adding 10 times 80% ethanol aqueous solution by volume and refluxing 2 hours twice. The extraction rate of macrocyclic polyphenols was above 90% with this process. Conclusion This assay method is accurate, stable, and repeatable. The optimized extraction process is stable and feasible for further development and utilization.