学龄前儿童每日步数与心肺适能的剂量-效应关系研究

Dose-response Relationship between Daily Step Counts and Cardiorespiratory Fitness in Preschool Children

目的:探索学龄前儿童每日步数与心肺适能之间的量效关系。方法:通过方便抽样募集到上海市401名学龄前儿童,采用ActiGraph GT3X+测量每日步数,20 m往返跑估算的最大摄氧量(VO_(2max))反映受试者心肺适能。将数据按性别分组,分别采用逻辑回归和线性回归检验每日步数与心肺适能之间的关系。结果:共295名(男童168名,女童127名;月龄57.67±5.32月)学龄前儿童被纳入最终统计分析。调整混杂因素后,以每日步数下四分位数组为参考,男、女童组每日步数上四分位数组VO_(2max)分别提高0.60(95%CI:0.02,1.19)和0.59(95%CI:0.08,1.10)ml/kg/min。同时,每日步数每增加1000步,男、女童VO_(2max)分别提高0.13(95%CI:0.02,0.25)和0.11(95%CI:-0.01,0.22)ml/kg/min。此外,每日步数与VO_(2max)之间在男童中存在曲线关系,当每日步数<6000步时,VO_(2max)的效应值间无显著统计学差异;当每日步数≥6000步时,每日步数每增加1000步,VO_(2max)提高0.20(95%CI:0.07,0.34)ml/kg/min。结论:学龄前儿童每日步数与心肺适能间存在显著的正向剂量-效应关系。为达到较好的心肺适能水平,建议男童每日步数至少积累6000步。

Objective:To investigate the dose-response relationship between daily step counts and cardiorespiratory fitness in preschool children.Method:Step counts of 401 preschool children in Shanghai were measured by wearing ActiGraph GT3X+accelerometers for consecutive 7 days.Cardiorespiratory fitness was measured by 20 meters shuttle run test to estimate maximal oxygen consumption VO_(2max).Logistic and linear regressions were applied to analyze the association between step counts and cardiorespiratory fitness.Results:295 participants were included in the final statistical analysis(168 boys,127 girls,mean age 57.67±5.32 months).After adjusting for confounders,compared with Q1 group,boys and girls in the highest quartile of daily step counts yielded VO_(2max)increment of 0.60(95%CI:0.02,1.19)and 0.59(95%CI:0.08,1.10)ml/kg/min.Meanwhile,dose-response relationship was observed for each 1000 steps/day increment associated with 0.13(95%CI:0.02,0.25)and 0.11(95%CI:-0.01,0.22)ml/kg/min in boys and girls,respectively.In addition,a threshold of 6000 steps/day was observed in boys.The cardiorespiratory fitness did not show significance when step counts below 6000 steps/day,after which it increased 0.20(95%CI:0.07,0.34)ml/kg/min for each 1000 steps/day increment.Conclusions:Positive dose-response relationship existed between daily step counts and cardiorespiratory fitness in preschool children.And at least 6000 steps/day was recommended for boys to achieve the better cardiorespiratory fitness level.