A cluster-randomized controlled trial to reduce sedentary behavior and promote physical activity and health of 8-9 year olds: The Transform-Us! Study Accelerometer-measured sedentary time and physical activity-A 15 year follow-up of mortality in a Swedish population-based cohort. Correlates of preschool children’s objectively measured physical activity and sedentary behavior: a cross-sectional analysis of the SPLASHY study Associations Between Screen-Based Sedentary Behavior and Cardiovascular Disease Risk Factors in Korean Youth Sedentary behavior and mortality in older women: the Women's Health Initiative. The Active for Life Year 5 (AFLY5) school based cluster randomised controlled trial: study protocol for a randomized controlled trial A school-based physical activity program to improve health and fitness in children aged 6–13 years ("Kinder-Sportstudie KISS"): study design of a randomized controlled trial [ISRCTN15360785] Intervening to Reduce Sedentary Behaviors and Childhood Obesity among School-Age Youth: A Systematic Review of Randomized Trials Effect of a school-based intervention to promote healthy lifestyles in 7–11 year old children Relative risk of mortality in the physically inactive is underestimated because of real changes in exposure level during follow-up. Patterns of Sedentary Behavior and Mortality in U.S. Middle-Aged and Older Adults Effects of modifying physical activity and sedentary behavior on psychosocial adjustment in overweight/obese children. One-year changes in physical activity and sedentary behavior among adolescents: the Croatian Physical Activity in Adolescence Longitudinal Study (CRO-PALS). Physical activity, sedentary behavior, and adiposity in English children. Physical activity, sedentary behavior, and cause-specific mortality in black and white adults in the Southern Community Cohort Study. Objective measures of activity level and mortality in older men. Self-reported physical activity predicts long-term coronary heart disease and all-cause mortalities. Twenty-one-year follow-up of the Israeli Ischemic Heart Disease Study.
Background Physical activity ( PA ) is associated with positive cardio-metabolic health and emerging evidence suggests sedentary behavior ( SB ) may be detrimental to children 's health independent of PA . The primary aim of the Transform-Us ! study is to determine whether an 18-month , behavioral and environmental intervention in the school and family setting s results in higher levels of PA and lower rates of SB among 8 - 9 year old children compared with usual practice ( post-intervention and 12-months follow-up ) . The secondary aims are to determine the independent and combined effects of PA and SB on  children 's cardio-metabolic health risk factors ; identify the factors that mediate the success of the intervention ; and determine whether the intervention is cost-effective . Methods / design A four-arm cluster-r and omized controlled trial ( RCT ) with a 2 × 2 factorial design , with schools as the unit of r and omization . Twenty schools will be allocated to one of four intervention groups , sedentary behavior ( SB-I ) , physical activity ( PA-I ) , combined SB and PA ( SB+PA-I ) or current practice control ( C ) , which will be evaluated among approximately 600 children aged 8 - 9 years in school year 3 living in Melbourne , Australia . All children in year 3 at intervention schools in 2010 ( 8 - 9 years ) will receive the intervention over an 18-month period with a maintenance ' booster ' delivered in 2012 and children at all schools will be invited to participate in the evaluation assessment s. To maximize the sample and to capture new students arriving at intervention and control schools , recruitment will be on-going up to the post-intervention time point . Primary outcomes are time spent sitting and in PA assessed via accelerometers and inclinometers and survey . Discussion To our knowledge , Transform-Us ! is the first RCT to examine the effectiveness of intervention strategies for reducing children 's overall sedentary time , promoting PA and optimizing health outcomes . The integration of consistent strategies and messages to children from teachers and parents in both school and family setting s is a critical component of this study , and if shown to be effective , may have a significant impact on educational policies as well as on pedagogical and parenting practice s . Trial registration ACTRN12609000715279 ; Current Controlled Trials IS RCT OBJECTIVES To investigate the associations of objective ly assessed sedentary time , light intensity physical activity ( PA ) , moderate to vigorous intensity PA ( MVPA ) , and total PA with all-cause mortality and mortality from cardiovascular disease ( CVD ) or cancer in a Swedish population -based cohort with 15 years follow-up time . DESIGN Longitudinal prospect i ve cohort study . METHODS Data from 851 persons ( 56 % women ) ≥35 years at baseline were included . Primary exposure variables were  time ( min/day ) spent sedentary , in light intensity PA and in MVPA , and total counts from an Actigraph 7164 accelerometer . Data on all-cause mortality and mortality from CVD or cancer were obtained from Swedish registers . Cox proportional hazards models estimated hazard ratios ( HR ) of mortality with 95 % confidence intervals ( CI ) . RESULTS Compared with the least sedentary participants , those in the most sedentary tertile had an increased risk of all-cause mortality , HR : 2.7 ( 1.4 , 5.3 ) , CVD mortality , HR : 5.5 ( 1.4 , 21.2 ) and cancer mortality , HR : 4.3 ( 1.2 , 16.0 ) . For all-cause mortality , those in the highest light intensity PA tertile had a HR 0.34 ( 0.17 , 0.67 ) compared with the lowest tertile . A similar pattern was found for CVD and cancer mortality . More time spent in MVPA was associated with the largest risk reduction for CVD mortality , with an almost 90 % lower risk in the tertile with the most time in MVPA . CONCLUSIONS This study confirms a strong inverse relationship between MVPA and mortality , and adds new insight for the underst and ing of the associations between sedentary time  and light intensity PA  and mortality Background Identifying ways to promote physical activity and decrease sedentary time during childhood is a key public health issue . Research on the putative influences on preschool children ’s  physical activity ( PA ) and  sedentary behavior  ( SB ) is limited and has yielded inconsistent results . Our aim was to identify correlates of PA and SB in preschool children . Methods Cross-sectional data were drawn from the Swiss Preschoolers ’ Health Study ( SPLASHY ) , a Swiss population -based cohort study . Of 476 two to six year old children , 394 ( 54 % boys ) had valid PA data assessed by accelerometry .  Information on exposure data was directly measured or extracted from parental question naires . Multilevel linear regression modeling was used to separately assess associations between 35 potential correlates and  total PA ( TPA ) , moderate-to-vigorous PA ( MVPA ) and SB . Results In total , 12 correlates from different domains were identified . TPA and MVPA were greater in boys than girls , increased with age and were positively associated with gross motor skills . Children from single parent families had a higher level of TPA and spent less time sedentary than those living with two parents . Time spent outdoors was positively associated with TPA and negatively with SB . The child ’s activity temperament was related all three outcomes , whereas parental sports club membership , living area per person and neighborhood safety were associated with SB only . Fixed and r and om factors in the final models accounted for 28 % , 32 % and 22 % of the total variance in TPA , MVPA and SB , respectively . Variance decomposition revealed that age , sex and activity temperament were the most influential correlates of both , TPA and MVPA , whereas the child ’s activity temperament , time outdoors and neighborhood safety were identified as the most important correlates of SB . Conclusions A multidimensional set of correlates of young children ’s  activity behavior has been identified . Personal factors had the greatest influence on PA , whereas environmental-level factors had the greatest influence on SB . Moreover , we identified a number of previously unreported , potentially modifiable correlates of young children ’s PA and SB . These factors could serve to define target groups or become valuable targets for change in future interventions .Trial registration Current Controlled Trials IS RCT N41045021 ( date of registration : 21.03.14 ) The purpose s of this study were to : 1 ) describe the patterns of screen-based sedentary behaviors  , and 2 ) examine the association between  screen-based sedentary behavior and cardiovascular disease ( CVD ) risk factors in representative Korean children and adolescents , aged 12 to 18 yr , in the Korean National Health and Nutrition Examination Survey .  Screen-based sedentary behavior  was measured using self-report question naires that included items for time spent watching TV and playing PC/video games . Physical activity  was measured using items for frequency and duration of moderate-to-vigorous physical activity ( MVPA )  . CVD risk factors such as body mass index ( BMI ) , waist circumference , LDL cholesterol , HDL cholesterol , total cholesterol , triglycerides , glucose , systolic blood pressure , and diastolic blood pressure were measured . Boys spent more time playing PC/video games , and girls spent more time watching TV . After adjusting for age , gender , annual household income , and MVPA , an additional hour of watching TV was significantly associated with the risk of overweight ( OR 1.17 [ 95 % CI 1.03 - 1.33 ] ) , high abdominal adiposity ( OR 1.27 [ 1.06 - 1.51 ] ) , and low HDL cholesterol ( OR 1.27 [ 1.10 - 1.47 ] ) . An additional hour spent playing PC/video games  also increased the risk of high abdominal adiposity ( OR 1.20 [ 1.03 - 1.40 ] ) . Prospect i ve observations and interventions are needed to determine causal relationships between  screen-based sedentary behavior  and CVD risk profiles in Korean youth BACKGROUND Although epidemiologic studies have shown associations between sedentary behavior and mortality , few have focused on older women with adequate minority representation and few have controlled for both physical activity and functional status . PURPOSE The objective of this study was to determine the relationship between sedentary time and total ; cardiovascular disease ( CVD ) ; coronary heart disease ( CHD ) ; and cancer mortality in a prospect i ve , multiethnic cohort of postmenopausal women . METHODS The study population included 92,234 women aged 50 - 79 years at baseline ( 1993 - 1998 ) who participated in the Women 's Health Initiative Observational Study through September 2010 .  Self-reported sedentary time  was assessed by question naire and examined in 4 categories ( ≤4 , > 4 - 8 , ≥8 - 11 , > 11 hours ) . Mortality risks were examined using Cox proportional hazard models adjusting for confounders . Models were also stratified by age , race/ethnicity , body mass index , physical activity , physical function , and chronic disease to examine possible effect modification . Analyses were conducted in 2012 - 2013 . RESULTS The mean follow-up period was 12 years . Compared with women who reported the least sedentary time , women reporting the highest sedentary time had increased risk of all-cause mortality in the multivariate model ( HR=1.12 , 95 % CI=1.05 , 1.21 ) . Results comparing the highest versus lowest categories for CVD , CHD , and cancer mortality were as follows : HR=1.13 , 95 % CI=0.99 , 1.29 ; HR=1.27 , 95 % CI=1.04 , 1.55 ; and HR=1.21 , 95 % CI=1.07 , 1.37 , respectively . For all mortality outcomes , there were significant linear tests for trend . CONCLUSIONS There was a linear relationship between greater amounts  of sedentary time and mortality risk after controlling for multiple potential confounders Background Low levels of physical activity , high levels of sedentary behaviour and low levels of fruit and vegetable consumption are common in children and are associated with adverse health outcomes . The aim of this paper is to describe the protocol for a cluster r and omised controlled trial ( RCT ) design ed to evaluate a school-based intervention that aims to increase levels of physical activity  , decrease  sedentary behaviour  and increase consumption of fruit and vegetables in school children . Methods / design The Active for Life Year 5 ( AFLY5 ) study is a school-based , cluster RCT that targets school children in Year 5 ( age 9 - 10 years ) . All state junior/ primary schools in the area covered by Bristol City and North Somerset Council are invited to participate ; special schools are excluded . Eligible schools are r and omised to one of two arms : intervention arm ( receive the intervention 2011 - 2012 ) and control arm ( receive the intervention after the final follow-up assessment , 2013 - 2014 ) . The primary outcomes of the trial are levels of accelerometer assessed physical activity and sedentary behaviour and question naire assessed fruit and vegetable consumption . A number of secondary outcomes will also be measured , including body mass index , waist circumference and overweight/obesity . Outcomes will be assessed at baseline ( prior to intervention when the children are in Year 4 ) , at the end of intervention ' immediate follow-up ' and ' 12 months long-term ' follow-up . We will use r and om effects linear and logistic regression models to compare outcomes by r and omised arm . The economic evaluation from a societal perspective will take the form of a cost consequence analysis . Data from focus groups and interviews with pupils , parents and teachers will be used to increase underst and ing of how the intervention has any effect and is integrated into normal school activity . Discussion The results of the trial will provide information about the public health effectiveness of a school-based intervention aim ed at improving levels of physical activity , sedentary behaviour and diet in children . Trial registration IS RCT Background Childhood obesity is the result of a long lasting imbalance between energy intake and energy expenditure . A major contributing factor is physical inactivity which is closely linked to bone health , cardiovascular disease risk , fitness and psychological factors . The school seems to provide an excellent setting to enhance levels of  physical activity ( PA ) .  However , there is insufficient data from previous school-based intervention trials on how to enhance overall PA . It is also unknown whether an intervention aim ed at increasing PA is effective in improving the children 's health . The purpose of this paper is to outline the design of a school-based r and omized , controlled trial ( RCT ) aim ing to increase overall PA and to improve fitness and health in 6- to 13-year-old children . Methods / Design 15 schools were r and omized to the intervention ( n = 9 ) or the control ( n = 6 ) group , stratified by geographic region ( urban vs. rural ) and by age ( 1st and 5th grade ) . Participation was given for all children in the intervention group since in this group the intervention was part of the normal school curriculum . The intervention during one academic year consisted of : 1 . two additional physical education classes per week given by trained physical education teachers adding up to a total of five PA classes per week , 2 . short PA breaks ( 2–5 min each ) during academic lessons , 3 . PA home work , and 4 . adaptation of recreational areas around the school . All children underwent  anthropometric measurements , blood pressure assessment , fitness testing , measurement of PA  and they filled out question naires . At least 70 % of all children agreed to blood sampling and measurements of body composition and bone mineral measurements by dual energy x-ray absorptiometry . The primary endpoints of the study after one year were an increase in total PA by accelerometry , an increase in aerobic fitness measured by the 20 m shuttle run , a decrease in percent body fat derived from skinfold measurements and an increase in quality of life as assessed by the child health question naire in the intervention group compared to the control group . Secondary outcomes were overall fitness , differences in body composition including body fat distribution , cardiovascular risk factors , psychosocial health , bone mineral content and density of femur , lumbar spine and total body and food intake . Discussion Our preliminary data suggest that the children were representative of Swiss children with respect to sex , socio-demographic status , and body mass index . Short-term results can be expected by the beginning of 2007 . We hypothesized that our intervention will lead to an increase in PA , fitness and overall health . Based on our data , we aim to provide important information regarding the influence of such an intervention on these outcome measures in school-aged children and to provide nationwide guidelines to improve PA in children Objective . To assess the effectiveness of interventions that focus on reducing  sedentary behavior ( SB ) among school-age youth and to identify elements associated with interventions ' potential for translation into practice setting s. Methods . A comprehensive literature search was conducted using 4 data bases for peer- review ed studies published between 1980 and April 2011 . R and omized trials , which lasted at least 12 weeks , aim ed at decreasing  SB among children aged 6 to 19 years were identified . Results . Twelve studies were included ; 3 focused only on SB , 1 focused on  physical activity ( PA )  , 6 were combined SB and PA interventions , and 2 studies targeted SB , PA , and diet .  The majority of the studies were conducted in a school setting , while others were conducted in such setting s as clinics , community centers , and libraries . Conclusions . Overall , interventions that focused on decreasing SB were associated with reduction in time spent on SB and /or improvements in anthropometric measurements related to childhood obesity . Several of the studies did consider elements related to the intervention 's potential for translation into practice setting Background Physical inactivity is recognised as a public health concern within children and interventions to increase physical activity are needed . The purpose of this research was to evaluate the effect of a school-based healthy lifestyles intervention on physical activity , fruit and vegetable consumption , body composition , knowledge , and psychological variables . Method A non-r and omised controlled study involving 8 primary schools ( 4 intervention , 4 control ) . Participants were 589 children aged 7–11 years . The intervention lasted 10 months and comprised a CD-rom learning and teaching re source for teachers ; an interactive website for pupils , teachers and parents ; two highlight physical activity events ( 1 mile school runs/walks ) ; a local media campaign ; and a summer activity wall planner and record . Primary outcome measures were objective ly measured physical activity ( pedometers and accelerometers ) and fruit and vegetable consumption . Secondary outcomes included body mass index , waist circumference , estimated percent body fat , knowledge , psychological variables . Multi-level modelling was employed for the data analysis . Results Relative to children in control schools , those in intervention schools significantly increased their total time in moderate-to-vigorous physical activity ( MVPA ) ( by 9 minutes/day vs a decrease of 10 minutes/day ) , their time in MVPA bouts lasting at least one minute ( 10 minutes/day increase vs no change ) and increased daily steps ( 3059 steps per day increase vs 1527 steps per day increase ) . A similar pattern of results was seen in a subset of the least active participants at baseline . Older participants in intervention schools showed a significant slowing in the rate of increase in estimated percent body fat , BMI , and waist circumference . There were no differences between groups in fruit and vegetable intake . Extrinsic motivation decreased more in the intervention group . Conclusion The intervention produced positive changes in physical activity levels and body composition . It appeared to have little or no effect on consumption of fruit and vegetables . Schools are a suitable setting for the promotion of healthy lifestyles although more work , particularly focussed on dietary change , is needed in a variety of schools and social setting Relative risk among exposure groups in prospect i ve cohort studies is based on the assumption that all subjects are exposed at the level recorded at baseline throughout the study . Changes in risk behavior during follow-up will dilute the relative risk . This prospect i ve cohort study in Copenhagen , Denmark , between 1964 and 1994 included 30,640 men and women ; 19,149 were examined twice , with an interval of 6.7 ( st and ard deviation , 3.4 ) years .  Relative risks calculated from baseline measurements for moderately active and sedentary groups compared with the highly active group were 1.11 ( 95 % confidence interval : 1.05 , 1.18 ) and 1.64 ( 95 % confidence interval : 1.53 , 1.75 ) , respectively . The relative risk between the highly active group and the sedentary group decreased with increasing follow-up time . When intraindividual changes in physical activity level during follow-up were taken into account , the relative risk of physical inactivity was 24 - 59 % higher compared with the relative risk estimated from baseline measurements . The risk of a sedentary lifestyle is underestimated when it is calculated from one baseline measurement in prospect i ve studies , because subjects change behavior during follow-up Adults are sedentary for an alarming 9 to 10 hours per day ( 1 ) . Accordingly , the popular press has coined the phrase sitting is the new smoking to describe a current epidemic of developed nations ( 24 ) . Evidence indicates that sedentary time is associated with incident cardiovascular disease , incidence of cardiovascular diseaserelated risk factors , and mortality ( 5 , 6 ) . Of note , the risk conferred by prolonged sedentariness is eliminated only by high levels of moderate- to vigorous-intensity physical activity ( MVPA ) ( about 60 to 75 min/d ) , which exceed physical activity recommendations ( 7 , 8) . As such , sedentary behavior is now believed to represent a clinical ly important aspect of a person 's physical activity profile and is no longer considered simply the extreme low end of the physical activity continuum ( 5 ) . Studies linking sedentary behavior to health outcomes have relied almost exclusively on self-reported  sedentary time  , which is subject to reporting bias and measurement error ( 9 ) . A 2015 systematic review ( 5 ) identified only 1 study ( NHANES [ National Health and Nutrition Examination Survey ] ) that examined the association between objective ly measured sedentary time and health outcomes , a study limited by a small event rate ( 10 ) . New studies using NHANES data have since been published , with longer follow-up and higher event rates ( 1115 ) . However , some of these studies have reported an association between objective ly measured sedentary time and mortality ( 11 , 14 , 15 ) , but others have not ( 12 , 13 ) . Additional cohort studies are thus needed to rectify evidence gaps . Furthermore , studies using accelerometers to objective ly measure sedentary behavior conventionally operationalize sedentary time as the total number of sedentary minutes per day . This approach ignores patterns of accumulated sedentary behavior over time . For example , accumulation of sedentary time in a few long bouts or many short bouts represents 2 distinct patterns of sedentary time accrual . Experimental studies have shown that acute periods of prolonged , uninterrupted sedentary behavior cause greater detrimental cardiometabolic effects than sedentary behavior that is periodically interrupted ( 1618 ) , suggestive that it is not just total sedentary time that is relevant to health outcomes , but also the manner in which it is accumulated . Few longitudinal studies , however , have explored the association between prolonged , uninterrupted sedentary behavior and mortality to corroborate these findings . To inform guidelines on reducing sedentary behavior ( target reductions in overall sedentary time or target interruption of prolonged sedentary bouts ) , evidence from prospect i ve studies is needed to 1 ) confirm the association between total sedentary time and mortality using objective measures , 2 ) determine whether prolonged sedentary bouts confer risk for death , and 3 ) eluci date whether the total volume of sedentary time and its pattern of accumulation individually or jointly contribute to risk for death . The purpose of this study , therefore , was to examine the association between objective ly measured sedentary time ( both total volume and accrual in prolonged bouts ) and all-cause mortality in a national cohort of U.S. middle-aged and older adults enrolled in the REGARDS ( Reasons for Geographic and Racial Differences in Stroke ) study . Methods Study Population REGARDS is a population -based study design ed to examine racial and regional disparities in stroke . It comprises 30239 white and black adults aged 45 years or older enrolled between 2003 and 2007 from across the contiguous United States ( 19 , 20 ) . Detailed design and methods for REGARDS are described elsewhere ( 21 ) . Briefly , demographic and cardiovascular risk factor data were collected by telephone interview and an in-home physical assessment on enrollment . A detailed summary of baseline measures is provided in the Supplement . Participants ( or their proxies ) were then followed for 6-month intervals to ascertain vital status . Objective measurements of sedentary behavior were collected from active REGARDS participants from 2009 to 2013 ( mean time from study enrollment , 5.7 years [ SD , 1.5 ] ; range , 1.9 to 9.5 years ) ( 22 ) . A total of 7985 participants adhered to accelerometer wear requirements ( 4 days with accelerometer wear 10 hours ) , provided follow-up data , and were available for the current analyses ( Supplement Figure 1 ) . Supplement Table 1 shows the characteristics of included versus excluded REGARDS participants . The REGARDS study protocol was approved by the institutional review boards of participating institutions . All participants provided informed consent . Supplement . Supplementary Material Accelerometer Data Collection Methods for accelerometer data collection are described elsewhere ( 22 ) . Briefly , participants were fitted with an Actical ( Philips Respironics ) accelerometer secured to their right hip using a nylon belt and were instructed to wear the device during waking hours for 7 consecutive days . The Actical had been vali date d formeasurement of physical activity and sedentary behavior and was shown to have acceptable reliability ( 2325 ) . Activity counts were summed over 1-minute epochs . Nonwear periods were defined as at least 150 consecutive minutes of 0 activity counts . This nonwear algorithm was previously vali date d against daily log sheets in REGARDS participants ( 26 ) . Measurements of 0 to 49 , 50 to 1064 , and at least 1065 counts per minute were defined as sedentary behavior , light-intensity physical activity , and MVPA , respectively , as determined in a laboratory-based calibration study ( 27 ) . A sedentary bout was defined as consecutive minutes in which the accelerometer registered fewer than 50 counts per minute . A sedentary break was defined as at least 1 minute in which 50 or more counts per minute were registered after a sedentary bout . Both sedentary bouts and breaks were exclusively continuous periods , with no interruptions or nonwear intervals allowed in the definition . Outcome Ascertainment All-cause mortality was the primary outcome , defined as any death after completion of the accelerometer protocol regardless of cause . Date s of death were confirmed through review of death certificates , medical records , and administrative data bases . Deaths through 4 September 2015 were included in the current analysis . Statistical Analysis Sedentary and physical activity variables were averaged across compliant days ( 10 hours of wear ) . Because of a high correlation between total sedentary time and wear time ( Supplement Figure 2 ) , we corrected for the influence of wear time by st and ardizing total sedentary time to 16 hours of wear time per day using the residuals obtained when regressing total sedentary time on wear time ( see Methods section of the Supplement ) ( 2830 ) . Participants were stratified into quartiles according to total sedentary time and , separately , mean sedentary bout duration ( a measure of overall prolonged , uninterrupted sedentary behavior ) . Cox proportional hazards regression modeling was used to calculate the hazard ratio ( HR ) for all-cause mortality associated with quartiles of total sedentary time ( and separately , mean sedentary bout length ) . Crude HRs were initially calculated . Subsequent HRs were calculated after adjustment for age , race , sex , region of residence , education , and season the accelerometer was worn ( model 1 ) , with further adjustment for current smoking , alcohol use , body mass index ( BMI ) , diabetes , hypertension , dyslipidemia , estimated glomerular filtration rate less than 60 mL/min/1.73 m2 , atrial fibrillation , history of coronary heart disease , and history of stroke ( model 2 ) . Models were additionally adjusted for MVPA expressed continuously ( model 3 ) . Tests for linear trend across quartiles were conducted by including the quartile for each participant as an ordinal variable in regression models . Proportional hazards assumptions were confirmed with a Kolmogorov-type supremum test ( 31 ) . The above analyses were then repeated in a fully adjusted model , testing interactions for age ( < 65 and 65 years ) , sex ( male and female ) , race ( black and white ) , BMI category ( normal weight and overweight or obese ) , and MVPA category ( < 150 min/wk and 150 min/wk ) . As a secondary analysis , we examined the continuous doseresponse relationship between each sedentary characteristic and all-cause mortality in a fully adjusted model ( model 3 ) using restricted cubic splines ( 32 ) . Cubic polynomials were fitted with the mean of each sedentary characteristic set as the reference and knots placed at the 5th , 35th , 65th , and 95th percentiles ( 33 ) . Nonlinear associations were evaluated using the likelihood ratio test . For nonlinear associations , spline models were used to describe the associations and when the association was determined to be linear , a linear model was used . Because of multicollinearity between total sedentary time and mean sedentary bout duration ( r= 0.61 ) , both variables were not included in the same model . Alternatively , to examine the individual and joint associations of total sedentary time and prolonged , uninterrupted sedentary behavior with mortality , participants were classified into 4 categories : low total sedentary time ( < 750 min/d ) and low prolonged sedentary bout time ( < 10 min/bout ) , low total sedentary time  and high prolonged sedentary bout time  ( 10 min/bout ) , high total sedentary time  ( 750 min/d ) and low prolonged sedentary bout time , and high total sedentary time and high prolonged sedentary bout time . Hazard ratios for all-cause mortality were calculated for each joint category in comparison with the lowlow group in a fully adjusted model ( model 3 ) . Thresholds for total sedentary time ( 750 min/d ) and mean sedentary bout duration ( 10 min/bout ) were selected on the basis of the restricted cubic splines and were confirmed using a method described by Contal and O'Quigley ( see Methods section of the Supplement ) ( 34 ) . To allow for the possibility that sedentary bouts OBJECTIVES To evaluate the relationship between changes in  physical activity ( PA ) , sedentary behavior , and physical self-perceptions and global self-worth in 30 , 8 - 12 years old , overweight/obese children ( 13 boys , 17 girls ) . METHODS Secondary analyses from a r and omized controlled trial design ed to increase PA and reduce sedentary behavior . PA was measured by accelerometers worn by participants every day for 8 weeks .  Sedentary behavior , defined as minutes per day spent in television viewing , was assessed by self-report . RESULTS Increases in PA were associated with increases in perceived physical conditioning ( r = .54 , p < .01 ) , body satisfaction ( r = .55 , p < .01 ) , and overall physical self-worth ( r = .44 , p < .05 ) independent of changes in body mass index ( BMI ) . Reductions in TV viewing were also related to increased physical and global self-worth . CONCLUSIONS Increases in PA are associated with improvements in physical self-perceptions but not global self-worth , while reductions in TV viewing are associated with increased physical and global self-worth , and these psychosocial benefits appear to be independent of changes in adiposity Background Little is known about the concurrent change in  physical activity ( PA )  ,  sedentary behavior ( SB ) and  sport participation  ( SP ) during adolescence . The main purpose of this prospect i ve and partly objective study was to simultaneously investigate PA , SBs and SP changes between the 1st and 2nd grade s of high school in urban adolescents . Methods In this 1-year follow-up study , the participants were 81 secondary -school students ( 28 boys and 53 girls ) aged 15.5 years at the baseline .  PA was assessed with the SenseWear Armb and multi-sensor activity monitor , while SBs were assessed by using School Health Action , Planning and Evaluation System ( SHAPES ) PA question naire . The SHAPES question naire was supplemented with two questions inquiring about SP in organized sports in school and outside of school . Results PA decreased markedly in both genders between the 1st and 2nd grade s of high school . Total energy expenditure ( TEE ) was reduced by 13 kcal/kg/day on average in boys and by 10 kcal/kg/day in girls ( p for both < 0.001 ) , while mean daily active energy expenditure ( AEE ) decreased by 7 kcal/kg/day ( p < 0.001 ) and 3 kcal/kg/day ( p = 0.04 ) in boys and girls , respectively . Similarly , the amount of moderate PA declined by 49 min/day in boys and 21 min/day in girls ( p for both < 0.001 ) . At the same time vigorous PA was cut by 14 min/day ( p < 0.001 ) and 3 min/day ( p = 0.003 ) in boys and girls , respectively . Conversely , time spent in SBs did not show any change . Conclusion In conclusion , a decline in PA between the 1st and 2nd grade s of high school was marked but was not accompanied with an increase in SBs . Policies aim ed at increasing PA should be targeting the period of entering secondary school to offset the observed drop in PA BACKGROUND The importance of variation in total volume of physical activity or moderate- to vigorous-intensity physical activity ( MVPA ) to development of body fatness in childhood is unclear , and it is unclear if physical activity has a greater influence on adiposity in boys than girls . PURPOSE To assess relationships between 2-year changes in objective ly measured physical activity , sedentary behavior , and adiposity in English children . METHODS Prospect i ve cohort study , set in Northeast Engl and , of a socioeconomically representative sample of 403 children . Measures were change in accelerometer-determined physical activity and sedentary behavior  from age 7 to 9 years ( data collected 2006/2007 and 2008/2009 ; analyzed in 2010 ) and concurrent change in adiposity ( fat mass index derived from bioelectric impedance ) and change in BMI Z-score . RESULTS Decline in MVPA was associated with a greater increase in fat mass index in boys but not girls . Declining MVPA was associated with increased BMI Z-score in boys but not girls . Increased sedentary behavior was not associated with increased BMI Z-score in either gender . CONCLUSIONS Avoiding mid-late childhood reductions in MVPA may reduce excessive fat gain , although such strategies may have greater impact on boys than girls There is limited evidence demonstrating the benefits of physical activity with regard to mortality risk or the harms associated with sedentary behavior in black adults , so we examined the relationships between these health behaviors and cause-specific mortality in a prospect i ve study that had a large proportion of black adults . Participants ( 40 - 79 years of age ) enrolled in the Southern Community Cohort Study between 2002 and 2009 ( n = 63,308 ) were prospect ively followed over 6.4 years , and 3,613 and 1,394 deaths occurred in blacks and whites , respectively . Black adults who reported the highest overall physical activity level ( ≥32.3 metabolic equivalent-hours/day vs. < 9.7 metabolic equivalent-hours/day ) had lower risks of death from all causes ( hazard ratio ( HR ) = 0.76 . 95 % confidence interval ( CI ) : 0.69 , 0.85 ) , cardiovascular disease ( HR = 0.81 , 95 % CI : 0.67 , 0.98 ) , and cancer ( HR = 0.76 , 95 % CI : 0.62 , 0.94 ) . In whites , a higher physical activity level was associated with a lower risk of death from all causes ( HR = 0.76 , 95 % CI : 0.64 , 0.90 ) and cardiovascular disease ( HR = 0.69 , 95 % CI : 0.49 , 0.99 ) but not cancer ( HR = 0.95 , 95 % CI : 0.67 , 1.34 ) . Spending more time being sedentary ( > 12 hours/day vs. < 5.76 hours/day ) was associated with a 20%-25 % increased risk of all-cause mortality in blacks and whites . Blacks who reported the most time spent being sedentary ( ≥10.5 hours/day ) and lowest level of physical activity ( < 12.6 metabolic equivalent-hours/day ) had a greater risk of death ( HR = 1.47 , 95 % CI : 1.25 , 1.71 ) . Our study provides evidence that suggests that health promotion efforts to increase physical activity level and decrease  sedentary time could help reduce mortality risk in black adults OBJECTIVES To examine associations between objective measures of activity level and mortality risk in older men . DESIGN Prospect i ve cohort study . SETTING Six U.S. sites . PARTICIPANTS Men aged 71 and older followed an average of 4.5 years ( N = 2,918 ) .  MEASUREMENTS Time awake spent in sedentary behavior  ( metabolic equivalent ( MET ) level ≤1.50 ) , light activity  ( MET level 1.51 - 2.99 ) , and at least moderate activity  ( MET level ≥3.00 ) measured using an activity monitor worn for 5 days or longer and expressed as quartiles . Deaths were confirmed with death certificates ; cause of death was adjudicated by review of certificates and records . RESULTS During follow-up , 409 ( 14 % ) men died . After multivariable adjustment , comparing Q4 with Q1 , more time spent in sedentary behavior ( Q4 vs Q1 , hazard ratio ( HR ) = 1.51 , 95 % confidence interval ( CI ) = 1.10 - 2.08 ) , less time spent in light activity ( Q1 vs Q4 , HR = 1.54 , 95 % CI = 1.06 - 2.24 ) , and less time spent in at least moderate activity ( Q1 vs Q4 , HR = 1.56 , 95 % CI = 1.09 - 2.25 ) were similarly associated with greater mortality risk primarily due to higher risks of cardiovascular and noncardiovascular , noncancer death . The association between time spent in sedentary behavior and mortality varied according to time spent at higher activity level . More time spent in sedentary behavior was associated with greater risk of death in men spending 1.2 ( median ) h/d or more in at least moderate activity ( Q4 vs Q1 , HR = 2.09 , 95 % CI = 1.26 - 3.49 ) but not in those spending less time ( Q4 vs Q1 , HR = 1.02 , 95 % CI = 0.62 - 1.66 ) ( P = .005 for interaction ) . CONCLUSION In older men exceeding current guidelines on physical activity , more time spent in sedentary behavior is associated with greater mortality risk OBJECTIVE To determine whether self-reported physical activity predicts a decreased rate of coronary heart disease ( CHD ) and all-cause mortalities in middle-aged men when rates are adjusted for known confounders . DESIGN Cohort Analytic Study of Israeli government employees in 1963 . SUBJECTS Eight thous and four hundred sixty-three Israeli male government employees , aged 40 years or older , representing six areas of birth , excluding those with known cardiovascular disease in either 1963 or 1965 , from an original cohort of 10,059 . MAIN OUTCOME MEASURE Comparison of rates of death due to CHD and all causes , determined from death certificates in 21 years of follow-up , for subjects with different baseline levels of self-reported leisure-time and work-related physical activities measured in 1965 . RESULTS Self-reported leisure-time but not work-related physical activity was inversely related to both CHD ( adjusted relative risk , 0.79 ; 95 % confidence interval , 0.66 to 0.95 ) and all-cause mortalities ( adjusted relative risk , 0.91 ; 95 % confidence interval , 0.83 to 0.99 ) . Most of the apparent benefit accrued was from light physical activity on less than a daily basis . These inverse relationships persisted after adjustment for age , systolic blood pressure , cigarette smoking , total and high-density lipoprotein cholesterol levels , body mass index , psychosocial factors , and other potential confounders . CONCLUSION Baseline levels of self-reported leisure-time physical activity predicted a decreased rate of CHD and all-cause mortalities in employed middle-aged Israeli men followed up prospect ively for 21 years
There is a large body of evidence from all study design s which suggests that decreasing any type of sedentary time is associated with lower health risk in youth aged 5 - 17 years .
In particular , the evidence suggests that daily TV viewing in excess of 2 hours is associated with reduced physical and psychosocial health , and that lowering sedentary time leads to reductions in BMI
Accumulating evidence suggests that , independent of physical activity levels , sedentary behaviours are associated with increased risk of cardio-metabolic disease , all-cause mortality , and a variety of physiological and psychological problems .
Therefore , the purpose of this systematic review is to determine the relationship between sedentary behaviour and health indicators in school-aged children and youth aged 5 - 17 years .