Dose-response Relationship Of Physical Activity And Sedentary Behavior Patterns With Osteoporosis In Older Women

Objective:This study used objective measurement methods to explore the dose-response relationship between physical activity(PA),sedentary behavior(SEB),and osteoporosis in older women from the perspectives of different patterns,combinations,and isotemporal substitutions,to provide targeted physical activity recommendations for older women with osteoporosis.Methods:(1)The baseline data of Physical Activity and Health in Older Women Study(PAHIOWS),which enrolled 1370 participants through community centers,was used for data analysis.Information about social demographics,personal lifestyle habits,and health questionnaire of participants were collected through one-on-one,face-to-face interview.(2)Bone mineral density(BMD)-related data were measured by Sonost-2000 ultrasonic bone densitometry.PA and SEB data were collected by instructing participants to wear a wGT3X-BT tri-axial accelerometer for 7 consecutive days.PA variables include Light Physical Activity(LPA)and Moderate to Vigorous Physical Activity(MVPA),which were divided into total LPA,sporadic LPA(a bout of LPA continued less than 10 minutes),bouted LPA(a bout of LPA continued more than 10 minutes),total MVP A,sporadic MVPA(a bout of MVP A continued less than 10 minutes)and bouted MVP A(a bout of MVPA continued more than 10 minutes)based on duration.SEB variables were divided into total SEB,10min routed SEB(a bout of SEB time continued more than 10 minutes),30min routed SEB(a bout of SEB time continued more than 30 minutes)and 60min routed SEB(a bout of SEB time continued more than 60 minutes)based on duration.(3)After normality test and independent sample t test,Wilcoxon rank sum test was conducted for continuous variables that were not normally distributed,chi square test was used for categorical variable to explore the differences between the variables of the non-osteoporosis group and osteoporosis group.Multivariate adjusted binary logistic regression was used to explore the dose-response relationship between PA and SEB with different models and combinations and osteoporosis in older women.Isotemporal substitution model was used to explore the relationship between the same time redistribution of PA and SEB with osteoporosis.Results:(1)Of the 1111 older women included in the final study,468(42.12%)had osteoporosis.The average daily SEB,LPA and MVPA time of older women were 548.48±117.75 minutes,306.81±71.24 minutes and 32.63± 19.30 minutes,respectively,and 50.86%of them completed the guideline of physical activity and sedentary behavior recommended by World Health Organization.There were significant group differences in age,BMI,grip strength,BMD Tscore,daily total SEB,10min-bouted SEB,30min-bouted SEB,60min-bouted SEB,total LPA and bouted LPA between the osteoporosis group and the normal group(P<0.05).(2)Analysis of logistic regression between associations of patterns of PA and SEB with osteoporosis found that,in older women,increasing 30min/day of total SEB,10min-bouted SEB,30min-bouted SEB and 60min-bouted SEB were all significantly associated with increased OR of osteoporosis(P<0.05).Increasing 10min/day of total LPA and bouted LPA daily was significantly correlated with a decreased OR of osteoporosis(P<0.05).After additionally adjusted sporadic LPA,bouted LPA remained significantly associated with a decreased OR value of osteoporosis(P<0.05).There was no association between total MVPA,sporadic LPA,sporadic MVPA,and bouted MVPA with osteoporosis(P>0.05).(3)Analysis of isotemporal substitution model showed that replacing 30 min/day of SEB with same amount of LPA significantly associated with reduced OR by 8%(P<0.05),and replacing 30 min/day of LPA with the same amount of SEB significantly associated with increased OR by 8%(P<0.05).Replacing 30 min/day of MVPA with same amount of SEB was not associated with osteoporosis,and vice versa.(4)The joint association analysis showed that,in the fully adjusted model,compared with the combination of high SEB and low LPA,low SEB and high LPA were significantly correlated with osteoporosis in older women(P<0.05),while low SEB and low LPA,as well as high SEB and high LPA,were not associated with osteoporosis in older women(P>0.05).Conclusions:(1)Increasing sedentary time,whether total sedentary time or cumulative time of 10minbouted SEB,30min-bouted SEB or 60min-bouted SEB,can increase the risk of osteoporosis in older women.(2)Light physical activity,especially bouted light physical activity,can lower the risk of osteoporosis in older women.(3)For older women,replacing sedentary behavior for the same amount of time with 30 minutes of light physical activity per day is associated with a reduced risk of osteoporosis,and may otherwise increase the risk of osteoporosis.(4)For older women with long sedentary time and short light physical activity time,reducing sedentary behavior while increasing light physical activity can delay the occurrence of osteoporosis.