Effect Of Sedentary Behavior On Risk Factors Associated With Metabolic Syndrome In Middle-Aged Women

PURPOSE:The aim of this study is to examine the relationship between explanationary variables including sedentary behavior(Sed),total physical activity(TPA)and cardiorespiratory fitness(CRF)by a cross-sectional survey and response variables involving the related risk factors of metabolic syndrome(MetS)and the risk of illness for middle-aged Chinese women.METHODS:198 recruited grown subjects who are healthy middle-aged women and whose ages are in a certain range(44.59±3.36)were measured respectively with the IPAQ and SBQ.CRF was assessed in Second step test.The sedentary time(ST)was then processed at different time intervals,which means it was divided according to the different time intervals:1h/d(<1h/d,1-2h/d,2-3h/d,3-4h/d,4-5h/d,5-6h/d,6-7h/d,7-8h/d,>8h/d),1.5h/d(<1.5h/d,1.5-3h/d,3-4.5h/d,5-6.5h/d,6.5-8h/d,>8h/d),2h/d(<2h/d,2-4h/d,4-6h/d,6-8h/d,>8h/d),2.5h/d(<2.5h/d,2.5-5h/d,5-7.5h/d,>7.5h/d)and 3h/d(<3h/d,3-6h/d,6-9h/d,>9h/d),MetS was defined by the guidelines for the prevention and treatment of dyslipidemia in Chinese adults.The difference between different sedentary time grouped by varied standards and MetS-related risk factors were evaluated by the methods of ANOVA and Multiple regression.The associations between the sedentary behavior and the MetS risk were analysed(using STATA,version 15.0).RESULTS:(1)The index TG,FPG and BMI increase by 1.69mmol/L,1.06mmol/L and 3.26kg/m2 for each additional hour of sitting time when the segment of ST is lh/d.These indexes increase by 1.43mmol/L,0.90mmol/L and 2.52kg/m2 for every lh/d growth in sitting time when the segment of ST is 2h/d(TG(p=0.008<0.01,FPG(p=0.013<0.05)and BMI(p=0.05))and go up by 1.83mmol/L,0.90mmol/L and 2.52kg/m2 respectively when the segment of ST is 3h/d(TG(p=0.001<0.01),FPG(p=0.013<0.05)and BMI(p=0.05)).When lh/d and 2h/d were used as the segmentation standards of meditation time,it has a significant positive correlation with MetS-related risk indicators TG,FPG and BMI if ST>8h/d;This relationship only exists with ST>9 h/d.(2)When the total physical activity is added into the explanatoary variables,no matter how the ST is grouped,the contents of TG,FPG and BMI increase by 1.78mmol/L,1.08mmol/L and 3.21kg/m2 as long 1s the sitting time reaches 8h/d or more for each additional unit of sitting time,which shows the impact of sitting time on MetS related risk factors was barely affected by TPA.This indicates that sitting time and TPA are independently related to the MetS related risk indicators respectively.(3)The effect of segment sitting time on MetS-related risk factors is not affected by CRF when the cardiorespiratory fitness is added.No matter how many hours are set as the interval unit,the contents of TG,FPG and BMI increased by 1.67mmol/L,1.07mmol/L and 3.11kg/m2 as long as the sitting time reached 8h/d or more for each additional unit of sitting time.In addition,the contents of LDL-C and TC decrease by 0.03mmol/L and 0.03mmol/L and are independent in sedentary behavior when the CRF increases a unit.(4)There is a significant positive correlation between meditation time and MSrelated risk indicators when the total physical activity and cardiorespiratory fitness were explanatory variables.No matter how many hours were set as the interval unit,the contents of TG,FPG and BMI increased by 1.78mmol/L,1.09mmol/L and 3.00kg/m2 if the sitting time reached more than 8h/d for each additional unit of sitting time.CRF is negatively correlated with MetS risk indicators LDL-C and TC.Namely,the contents of LDL-C and TC decrease by 0.03mmol/L and 0.03mmol/L and are independent in sedentary behavior and TPA for each additional unit of CRF.TPA is negatively correlated with Mets related risk indicator TG.That means when TPA increases,the content of TG,MetS related risk indicator,tends to decrease.CRF and sitting time are not affected.Therefore,sitting time is independent of CRF and TPA.(5)These analyses suggest that compared to sit time grouped with the 3 h/d,when the sitting time>9 h/d,MS risk is 1.03 times and H-TC risk at 6.76 times than their original data respectively.The ratios of H-BC risk,H-FPG risk and L-HDL-C risk are 1.91 times,3.13 times,and 3.83 times respectively.Conclusions:(1)Sedentary time is significantly positively correlated with MetS related risk indicators.More exactly,8h/d is the main critical threshold where sitting time leads to changes in MetS-related risk factors.And it may be more appropriate to use 1h/d or 2h/d as the grouping criteria.(2)Both total physical activity and cardiorespiratory fitness are negatively correlated with MetS-related risk factors and sitting time is independent of PA and CRF respectively.(3)The impact of sedentary behavior on Mets related risk factors is independent of PA and CRF.There is a discrepancy in types and result when it comes to the impact of sedentary behavior,physical activity and cardiopulmonary endurance on MetS related risk factors.(4)Prolonged sitting time(>9h/d)has an adverse effect on the risk of excessive MS and ms-related risk indicators.In general,PA and CRF can both promote the improvement of Mets related risk indicators due to the negative impact of sitting time on them.Therefore,it is suggested to reduce sitting time,increase physical activity and improve the level of cardiorespiratory fitness in order to prevent Mets related risk indicators and disease risk.