human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Purpose Imprecise measurement of physical activity variables might attenuate estimates of the beneficial effects of activity on health-related outcomes . We aim ed to compare the cardiometabolic risk factor dose-response relationships for physical activity and sedentary behaviour between accelerometer- and question naire-based activity measures . Methods  Physical activity and sedentary behaviour  were assessed in 317 adults by 7-day accelerometry and International Physical Activity Question naire ( IPAQ ) . Fasting blood was taken to determine insulin , glucose , triglyceride and total , LDL and HDL cholesterol concentrations and homeostasis model-estimated insulin resistance ( HOMAIR ) . Waist circumference , BMI , body fat percentage and blood pressure were also measured . Results For both accelerometer-derived sedentary time ( < 100 counts.min−1 ) and IPAQ-reported sitting time significant positive ( negative for HDL cholesterol ) relationships were observed with all measured risk factors – i.e. increased sedentary behaviour was associated with increased risk ( all p≤0.01 ) . However , for HOMAIR and insulin the regression coefficients were > 50 % lower for the IPAQ-reported compared to the accelerometer-derived measure ( p<0.0001 for both interactions ) . The relationships for moderate-to-vigorous physical activity ( MVPA ) and risk factors were less strong than those observed for sedentary behaviours , but significant negative relationships were observed for both accelerometer and IPAQ MVPA measures with glucose , and insulin and HOMAIR values ( all p<0.05 ) . For accelerometer-derived MVPA only , additional negative relationships were seen with triglyceride , total cholesterol and LDL cholesterol concentrations , BMI , waist circumference and percentage body fat , and a positive relationship was evident with HDL cholesterol ( p = 0.0002 ) . Regression coefficients for HOMAIR , insulin and triglyceride were 43–50 % lower for the IPAQ-reported compared to the accelerometer-derived MVPA measure ( all p≤0.01 ) . Conclusion Using the IPAQ to determine sitting time and MVPA reveals some , but not all , relationships between these activity measures and metabolic and vascular disease risk factors . Using this self-report method to quantify activity can therefore underestimate the strength of some relationships with risk factors Supplemental digital content is available in the text . OBJECTIVES : To investigate the effect of physical activity on the association between television viewing and overweight ( body mass index ( BMI ) ≥25 kg/m2 ) . DESIGN : Cross-sectional study administered by interview to adults r and omly selected from the electronic white pages . SUBJECTS : 3392 adults ( 64 % response rate ) from a representative population sample in the State of New South Wales , Australia . MEASUREMENTS : Self-reported height and weight , two-week leisure-time physical activity recall , one-week average television viewing recall . RESULTS : BMI and physical activity patterns were both associated with hours of television watched . Compared to those participants who reported watching less than one hour of television per day , those watching 1 to 2.5 hours were 93 % more likely to be overweight ( BMI ≥25 kg/m2 ) , those watching 2.5 to 4 hours were 183 % more likely to be overweight , those watching more than 4 hours per day were four times more likely to be overweight . Physical activity  was not directly associated with being overweight , but an interaction between activity and television watching was present . Respondents in the low , moderate and high physical activity categories who reported watching more than 4 hours of television per day were twice as likely to be overweight compared to those who watched less than one hour of television per day , irrespective of physical activity participation . CONCLUSIONS : With approximately half the Australian adult population overweight or obese , these findings indicate that public health strategies to reduce overweight and prevent weight gain may need to focus on reducing sedentary behaviours such as television viewing in addition to increasing physical activity PURPOSE Although moderate-to-vigorous physical activity is related to premature mortality , the relationship between sedentary behaviors and mortality has not been fully explored and may represent a different paradigm than that associated with lack of exercise . We prospect ively examined  sitting time  and mortality in a representative sample of 17,013 Canadians 18 - 90 yr of age . METHODS Evaluation of  daily sitting time  ( almost none of the time , one fourth of the time , half of the time , three fourths of the time , almost all of the time ) ,  leisure time physical activity , smoking status , and alcohol consumption  was conducted at baseline . Participants were followed prospect ively for an average of 12.0 yr for the ascertainment of mortality status . RESULTS There were 1832 deaths  ( 759 of cardiovascular disease ( CVD ) and 547 of cancer ) during 204,732 person-yr of follow-up . After adjustment for potential confounders , there was a progressively higher risk of mortality across higher levels of sitting time from all causes ( hazard ratios ( HR ) : 1.00 , 1.00 , 1.11 , 1.36 , 1.54 ; P for trend < 0.0001 ) and CVD ( HR:1.00 , 1.01 , 1.22 , 1.47 , 1.54 ; P for trend < 0.0001 ) but not cancer . Similar results were obtained when stratified by sex , age , smoking status , and body mass index . Age-adjusted all-cause mortality rates per 10,000 person-yr of follow-up were 87 , 86 , 105 , 130 , and 161 ( P for trend < 0.0001 ) in physically inactive participants and 75 , 69 , 76 , 98 , 105 ( P for trend = 0.008 ) in active participants across sitting time categories . CONCLUSIONS These data demonstrate a dose-response association between  sitting time  and mortality from all causes and CVD , independent of leisure time physical activity . In addition to the promotion of moderate-to-vigorous physical activity and a healthy weight , physicians should discourage sitting for extended periods Background Sarcopenia is associated with loss of independence and ill-health  in the elderly although the causes remain poorly understood . We examined the association between two screen-based leisure time sedentary activities ( daily TV viewing time and internet use ) and muscle strength . Methods and Results We studied 6228 men and women ( aged 64.9±9.1 yrs ) from wave 4 ( 2008 - 09 ) of the English Longitudinal Study of Ageing , a prospect i ve study of community dwelling older adults . Muscle strength was assessed by a h and grip test and the time required to complete five chair rises .  TV viewing and internet usage  were inversely associated with one another . Participants viewing TV ≥6hrs/d had lower grip strength ( Men , B = −1.20 kg , 95 % CI , −2.26 , −0.14 ; Women , −0.75 kg , 95 % CI , −1.48 , −0.03 ) in comparison to < 2hrs/d TV , after adjustment for age , physical activity , smoking , alcohol , chronic disease , disability , depressive symptoms , social status , and body mass index . In contrast , internet use was associated with higher grip strength ( Men , B = 2.43 kg , 95 % CI , 1.74 , 3.12 ; Women , 0.76 kg , 95 % CI , 0.32 , 1.20 ) . These associations persisted after mutual adjustment for both types of sedentary behaviour . Conclusions In older adults , the association between sedentary activities and physical function is context specific ( TV viewing vs. computer use ) . Adverse effects of TV viewing might reflect the prolonged sedentary nature of this behavior Background Evidence on the relation between leisure-time physical activity ( LTPA ) and health-related quality of life ( HRQoL )  in older adults is based primarily on clinical trials of physical exercise programs in institutionalized persons and on cross-sectional studies of community-dwelling persons . Moreover , there is no evidence on whether leisure-time sedentary behavior ( LTSB ) is associated with HRQoL independently of LTPA . This study examined the longitudinal association between LTPA , LTSB , and HRQoL in older community-dwelling adults in Spain . Methods Prospect i ve cohort study of 1,097 persons aged 62 and over . In 2003 LTPA in MET-hr/week was measured with a vali date d question naire , and LTSB was estimated by the number of sitting hours per week . In 2009 HRQoL was measured with the SF-36 question naire . Analyses were done with linear regression and adjusted for the main confounders . Results Compared with those who did no LTPA , subjects in the upper quartile of LTPA had better scores on the SF-36 scales of physical functioning ( β 5.65 ; 95 % confidence interval [ CI ] 1.32 - 9.98 ; p linear trend < 0.001 ) , physical role ( β 7.38 ; 95 % CI 0.16 - 14.93 ; p linear trend < 0.001 ) , bodily pain ( β 6.92 ; 95 % CI 1.86 - 11.98 ; p linear trend < 0.01 ) , vitality ( β 5.09 ; 95 % CI 0.76 - 9.41 ; p linear trend < 0.004 ) social functioning ( β 7.83 ; 95 % CI 2.89 - 12.75 ; p linear trend < 0.001 ) , emotional role ( β 8.59 ; 95 % CI 1.97 - 15.21 ; p linear trend < 0.02 ) and mental health ( β 4.20 ; 95 % CI 0.26 - 8.13 ; p linear trend < 0.06 ) . As suggested by previous work in this field , these associations were clinical ly relevant because the β regression coefficients were higher than 3 points . Finally , the number of sitting hours showed a gradual and inverse relation with the scores on most of the SF-36 scales , which was also clinical ly relevant . Conclusions Greater LTPA and less LTSB were independently associated with better long-term HRQoL in older adults BACKGROUND Physical activity is an important lifestyle which is often poorly assessed in epidemiological studies . The European Prospect i ve Investigation into Cancer Study -Norfolk cohort ( EPIC-Norfolk ) , a large population -based cohort study , has developed a comprehensive question naire to assess activity in different domains of life aim ed at assessing total energy expenditure . We report the repeatability of this instrument and its validity against repeated objective measures of fitness and energy expenditure undertaken throughout the time frame of reference of the question naire . METHODS The validity of the instrument was measured in 173 individuals r and omly selected from a continuing population -based cohort study .  Energy expenditure was assessed by four separate episodes of 4-day heart-rate monitoring , a method previously vali date d against whole body calorimetry and doubly-labelled water . Cardio-respiratory fitness was assessed by four repeated measures of sub-maximum oxygen uptake . At the end of the 12-month period , participants completed the physical activity question naire that assesses past-year activity at home , work and in recreation . Repeatability was assessed in a separate group of 399 r and omly selected participants in EPIC who completed the physical activity question naire twice with a 3-month interval . RESULTS The age- and sex-adjusted correlation between the objective measure of daytime energy expenditure and the sum of recreational and occupational reported physical activity ( in MET h per week ) was 0.28 ( P < 0.001 ) . The reported time spent in vigorous activity was correlated with cardio-respiratory fitness ( 0.16 , P < 0.05 ) and with the proportion of time when energy expenditure was more than five times basal ( 0.17 , P < 0.05 ) . The repeatability of the sum of recreational and occupational reported activity was high , r = 0.73 . CONCLUSIONS The indices of physical activity derived from this question naire have levels of validity and repeatability comparable to other physical activity instruments that are used in large epidemiological studies and which have undergone such intense development and testing The obesity epidemic is attributed in part to reduced physical activity . Evidence supports that reducing time spent sitting , regardless of activity , may improve the metabolic consequences of obesity . Analyses were conducted in a large prospect i ve study of US adults enrolled by the American Cancer Society to examine leisure time spent sitting and physical activity in relation to mortality .  Time spent sitting and physical activity were queried by question naire on 53,440 men and 69,776 women who were disease free at enrollment . The authors identified 11,307 deaths in men and 7,923 deaths in women during the 14-year follow-up . After adjustment for smoking , body mass index , and other factors , time spent sitting ( > or = 6 vs. <3 hours/day ) was associated with mortality in both women ( relative risk = 1.34 , 95 % confidence interval ( CI ) : 1.25 , 1.44 ) and men ( relative risk = 1.17 , 95 % CI : 1.11 , 1.24 ) . Relative risks for  sitting  ( > or = 6 hours/day ) and  physical activity  ( < 24.5 metabolic equivalent (MET)-hours/week ) combined were 1.94 ( 
    Output:
    
agent
Assessing SB as a sum of behaviours and using a previous day recall were the most promising features of existing tools .
Accuracy was poor for all existing tools , with underestimation and overestimation of SB .
There was a lack of evidence about sensitivity to change .
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Purpose Imprecise measurement of physical activity variables might attenuate estimates of the beneficial effects of activity on health-related outcomes . We aim ed to compare the cardiometabolic risk factor dose-response relationships for physical activity and sedentary behaviour between accelerometer- and question naire-based activity measures . Methods  Physical activity and sedentary behaviour  were assessed in 317 adults by 7-day accelerometry and International Physical Activity Question naire ( IPAQ ) . Fasting blood was taken to determine insulin , glucose , triglyceride and total , LDL and HDL cholesterol concentrations and homeostasis model-estimated insulin resistance ( HOMAIR ) . Waist circumference , BMI , body fat percentage and blood pressure were also measured . Results For both accelerometer-derived sedentary time ( < 100 counts.min−1 ) and IPAQ-reported sitting time significant positive ( negative for HDL cholesterol ) relationships were observed with all measured risk factors – i.e. increased sedentary behaviour was associated with increased risk ( all p≤0.01 ) . However , for HOMAIR and insulin the regression coefficients were > 50 % lower for the IPAQ-reported compared to the accelerometer-derived measure ( p<0.0001 for both interactions ) . The relationships for moderate-to-vigorous physical activity ( MVPA ) and risk factors were less strong than those observed for sedentary behaviours , but significant negative relationships were observed for both accelerometer and IPAQ MVPA measures with glucose , and insulin and HOMAIR values ( all p<0.05 ) . For accelerometer-derived MVPA only , additional negative relationships were seen with triglyceride , total cholesterol and LDL cholesterol concentrations , BMI , waist circumference and percentage body fat , and a positive relationship was evident with HDL cholesterol ( p = 0.0002 ) . Regression coefficients for HOMAIR , insulin and triglyceride were 43–50 % lower for the IPAQ-reported compared to the accelerometer-derived MVPA measure ( all p≤0.01 ) . Conclusion Using the IPAQ to determine sitting time and MVPA reveals some , but not all , relationships between these activity measures and metabolic and vascular disease risk factors . Using this self-report method to quantify activity can therefore underestimate the strength of some relationships with risk factors Supplemental digital content is available in the text . OBJECTIVES : To investigate the effect of physical activity on the association between television viewing and overweight ( body mass index ( BMI ) ≥25 kg/m2 ) . DESIGN : Cross-sectional study administered by interview to adults r and omly selected from the electronic white pages . SUBJECTS : 3392 adults ( 64 % response rate ) from a representative population sample in the State of New South Wales , Australia . MEASUREMENTS : Self-reported height and weight , two-week leisure-time physical activity recall , one-week average television viewing recall . RESULTS : BMI and physical activity patterns were both associated with hours of television watched . Compared to those participants who reported watching less than one hour of television per day , those watching 1 to 2.5 hours were 93 % more likely to be overweight ( BMI ≥25 kg/m2 ) , those watching 2.5 to 4 hours were 183 % more likely to be overweight , those watching more than 4 hours per day were four times more likely to be overweight . Physical activity  was not directly associated with being overweight , but an interaction between activity and television watching was present . Respondents in the low , moderate and high physical activity categories who reported watching more than 4 hours of television per day were twice as likely to be overweight compared to those who watched less than one hour of television per day , irrespective of physical activity participation . CONCLUSIONS : With approximately half the Australian adult population overweight or obese , these findings indicate that public health strategies to reduce overweight and prevent weight gain may need to focus on reducing sedentary behaviours such as television viewing in addition to increasing physical activity PURPOSE Although moderate-to-vigorous physical activity is related to premature mortality , the relationship between sedentary behaviors and mortality has not been fully explored and may represent a different paradigm than that associated with lack of exercise . We prospect ively examined  sitting time  and mortality in a representative sample of 17,013 Canadians 18 - 90 yr of age . METHODS Evaluation of  daily sitting time  ( almost none of the time , one fourth of the time , half of the time , three fourths of the time , almost all of the time ) ,  leisure time physical activity , smoking status , and alcohol consumption  was conducted at baseline . Participants were followed prospect ively for an average of 12.0 yr for the ascertainment of mortality status . RESULTS There were 1832 deaths  ( 759 of cardiovascular disease ( CVD ) and 547 of cancer ) during 204,732 person-yr of follow-up . After adjustment for potential confounders , there was a progressively higher risk of mortality across higher levels of sitting time from all causes ( hazard ratios ( HR ) : 1.00 , 1.00 , 1.11 , 1.36 , 1.54 ; P for trend < 0.0001 ) and CVD ( HR:1.00 , 1.01 , 1.22 , 1.47 , 1.54 ; P for trend < 0.0001 ) but not cancer . Similar results were obtained when stratified by sex , age , smoking status , and body mass index . Age-adjusted all-cause mortality rates per 10,000 person-yr of follow-up were 87 , 86 , 105 , 130 , and 161 ( P for trend < 0.0001 ) in physically inactive participants and 75 , 69 , 76 , 98 , 105 ( P for trend = 0.008 ) in active participants across sitting time categories . CONCLUSIONS These data demonstrate a dose-response association between  sitting time  and mortality from all causes and CVD , independent of leisure time physical activity . In addition to the promotion of moderate-to-vigorous physical activity and a healthy weight , physicians should discourage sitting for extended periods Background Sarcopenia is associated with loss of independence and ill-health  in the elderly although the causes remain poorly understood . We examined the association between two screen-based leisure time sedentary activities ( daily TV viewing time and internet use ) and muscle strength . Methods and Results We studied 6228 men and women ( aged 64.9±9.1 yrs ) from wave 4 ( 2008 - 09 ) of the English Longitudinal Study of Ageing , a prospect i ve study of community dwelling older adults . Muscle strength was assessed by a h and grip test and the time required to complete five chair rises .  TV viewing and internet usage  were inversely associated with one another . Participants viewing TV ≥6hrs/d had lower grip strength ( Men , B = −1.20 kg , 95 % CI , −2.26 , −0.14 ; Women , −0.75 kg , 95 % CI , −1.48 , −0.03 ) in comparison to < 2hrs/d TV , after adjustment for age , physical activity , smoking , alcohol , chronic disease , disability , depressive symptoms , social status , and body mass index . In contrast , internet use was associated with higher grip strength ( Men , B = 2.43 kg , 95 % CI , 1.74 , 3.12 ; Women , 0.76 kg , 95 % CI , 0.32 , 1.20 ) . These associations persisted after mutual adjustment for both types of sedentary behaviour . Conclusions In older adults , the association between sedentary activities and physical function is context specific ( TV viewing vs. computer use ) . Adverse effects of TV viewing might reflect the prolonged sedentary nature of this behavior Background Evidence on the relation between leisure-time physical activity ( LTPA ) and health-related quality of life ( HRQoL )  in older adults is based primarily on clinical trials of physical exercise programs in institutionalized persons and on cross-sectional studies of community-dwelling persons . Moreover , there is no evidence on whether leisure-time sedentary behavior ( LTSB ) is associated with HRQoL independently of LTPA . This study examined the longitudinal association between LTPA , LTSB , and HRQoL in older community-dwelling adults in Spain . Methods Prospect i ve cohort study of 1,097 persons aged 62 and over . In 2003 LTPA in MET-hr/week was measured with a vali date d question naire , and LTSB was estimated by the number of sitting hours per week . In 2009 HRQoL was measured with the SF-36 question naire . Analyses were done with linear regression and adjusted for the main confounders . Results Compared with those who did no LTPA , subjects in the upper quartile of LTPA had better scores on the SF-36 scales of physical functioning ( β 5.65 ; 95 % confidence interval [ CI ] 1.32 - 9.98 ; p linear trend < 0.001 ) , physical role ( β 7.38 ; 95 % CI 0.16 - 14.93 ; p linear trend < 0.001 ) , bodily pain ( β 6.92 ; 95 % CI 1.86 - 11.98 ; p linear trend < 0.01 ) , vitality ( β 5.09 ; 95 % CI 0.76 - 9.41 ; p linear trend < 0.004 ) social functioning ( β 7.83 ; 95 % CI 2.89 - 12.75 ; p linear trend < 0.001 ) , emotional role ( β 8.59 ; 95 % CI 1.97 - 15.21 ; p linear trend < 0.02 ) and mental health ( β 4.20 ; 95 % CI 0.26 - 8.13 ; p linear trend < 0.06 ) . As suggested by previous work in this field , these associations were clinical ly relevant because the β regression coefficients were higher than 3 points . Finally , the number of sitting hours showed a gradual and inverse relation with the scores on most of the SF-36 scales , which was also clinical ly relevant . Conclusions Greater LTPA and less LTSB were independently associated with better long-term HRQoL in older adults BACKGROUND Physical activity is an important lifestyle which is often poorly assessed in epidemiological studies . The European Prospect i ve Investigation into Cancer Study -Norfolk cohort ( EPIC-Norfolk ) , a large population -based cohort study , has developed a comprehensive question naire to assess activity in different domains of life aim ed at assessing total energy expenditure . We report the repeatability of this instrument and its validity against repeated objective measures of fitness and energy expenditure undertaken throughout the time frame of reference of the question naire . METHODS The validity of the instrument was measured in 173 individuals r and omly selected from a continuing population -based cohort study .  Energy expenditure was assessed by four separate episodes of 4-day heart-rate monitoring , a method previously vali date d against whole body calorimetry and doubly-labelled water . Cardio-respiratory fitness was assessed by four repeated measures of sub-maximum oxygen uptake . At the end of the 12-month period , participants completed the physical activity question naire that assesses past-year activity at home , work and in recreation . Repeatability was assessed in a separate group of 399 r and omly selected participants in EPIC who completed the physical activity question naire twice with a 3-month interval . RESULTS The age- and sex-adjusted correlation between the objective measure of daytime energy expenditure and the sum of recreational and occupational reported physical activity ( in MET h per week ) was 0.28 ( P < 0.001 ) . The reported time spent in vigorous activity was correlated with cardio-respiratory fitness ( 0.16 , P < 0.05 ) and with the proportion of time when energy expenditure was more than five times basal ( 0.17 , P < 0.05 ) . The repeatability of the sum of recreational and occupational reported activity was high , r = 0.73 . CONCLUSIONS The indices of physical activity derived from this question naire have levels of validity and repeatability comparable to other physical activity instruments that are used in large epidemiological studies and which have undergone such intense development and testing The obesity epidemic is attributed in part to reduced physical activity . Evidence supports that reducing time spent sitting , regardless of activity , may improve the metabolic consequences of obesity . Analyses were conducted in a large prospect i ve study of US adults enrolled by the American Cancer Society to examine leisure time spent sitting and physical activity in relation to mortality .  Time spent sitting and physical activity were queried by question naire on 53,440 men and 69,776 women who were disease free at enrollment . The authors identified 11,307 deaths in men and 7,923 deaths in women during the 14-year follow-up . After adjustment for smoking , body mass index , and other factors , time spent sitting ( > or = 6 vs. <3 hours/day ) was associated with mortality in both women ( relative risk = 1.34 , 95 % confidence interval ( CI ) : 1.25 , 1.44 ) and men ( relative risk = 1.17 , 95 % CI : 1.11 , 1.24 ) . Relative risks for  sitting  ( > or = 6 hours/day ) and  physical activity  ( < 24.5 metabolic equivalent (MET)-hours/week ) combined were 1.94 ( 
    Output:
    