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: Study Design . A population -based cross-sectional and 5-year prospect i ve question naire study . Objective . To investigate self-reported physical workload as a risk factor for low back pain . Summary of Background Data . Both physical and psychosocial workplace factors are considered risk factors for low back pain . However , today no consensus has been reached regarding the exact role of these factors in the genesis of low back pain . Methods . Question naire data were collected at baseline for 1397 ( and after 5 years for 1163 ) men and women aged 31–50 years at baseline .  Low back pain ( “ any low back pain within the past year , ” “ low back pain ≤ 30 days in total during the past year , ” “ low back pain > 30 days in total during the past year ” ) was analyzed in relation to physical workload ( sedentary , light physical , and heavy physical work ) using logistic regression and controlling for age , gender , and social group . The proportions of workers changing between the workload groups over the 5-year period were analyzed in relation to low back pain status . Results . At baseline no statistically significant differences in low back pain outcomes were found for workers exposed to sedentary , light physical , or heavy physical work . This was true for all age , gender , and social groups . At follow-up there was a statistically significant dose – response association between any low back pain and longst and ing low back pain within the past year and increasing physical workload  at baseline also after controlling for age , gender , and social group . Subjects with heavy physical workload at baseline changed statistically significantly more often to sedentary work if they experienced low back pain for more than 30 days out of the past year . Conclusions . Having a sedentary job might have a protective or neutral effect in relation to low back pain , whereas having a heavy physical job constitutes a significant risk factor . Because of migration between exposure groups ( the “ healthy-worker ” effect ) , longitudinal studies are necessary for investigating the associations between physical workload and low back pain Study Design . Prospect i ve cohort study . Objectives . To investigate whether physical performance , grip strength , cognitive function , and depression symptomatology are risk factors for incident low back pain ( LBP ) over a 2-year period in seniors . Summary of Background Data . LBP is common in the older age groups , but little is known about predictors of LBP in this age group . Methods . Data from the 2001 and 2003 data collection from the population -based Longitudinal Study of Aging Danish Twins formed the basis of this analysis . Participants free from LBP at baseline ( no LBP during the past month , N = 1387 ) were included and interview data on overall physical function , and assessment of grip strength , overall cognitive function , and depression at baseline were obtained . LBP status at follow-up was assessed using a modified version of the St and ardized Nordic Question naire . Logistic regression was used to assess the associations between the baseline risk factors and LBP at follow-up . Results . A total of 1387 persons 70 to 100 years of age at baseline were included in the analyses . Of the initially LBP-free individuals , 7 % had experienced LBP more than 30 days out of the past year , 7 % had altered or decreased their physical activities due to LBP , and 11 % had received treatment for LBP at follow-up . Good overall physical function ( being among the top 50 % ) at baseline was protective for LBP of more than 30 days duration and for diminishing physical activities due to LBP and for care seeking due to LBP . High depression scores ( being among the top 25 % ) were strongly associated with altering or decreasing daily activities because of LBP . Grip strength and overall cognitive performance at baseline were associated with lower incidence of LBP and decreasing activities due to LBP at follow-up ; however , these associations were not statistically significant . Conclusion . Poor overall physical function and depression symptomatology are associated with LBP and consequences of LBP in persons 70 years of age and older Introduction : Behaviorally oriented grade d activity interventions have been suggested for sick-listed workers with low back pain on return to work , but have not been extensively evaluated . Methods : One hundred and thirty-four workers were r and omly assigned to either a grade d activity intervention ( n = 67 ) or usual care ( n = 67 ) and followed-up for 12 months . Results : The grade d activity group returned back to work faster with a median of 54 days compared to 67 days in the usual care group . The grade d activity intervention was more effective after approximately 50 days post-r and omization ( HRR = 1.9 , CI = 1.2–3.1 , p = 0.01 ) . Differences between the groups in number of recurrent episodes , total number of days of sick leave due to low back pain , and total number of days of sick leave due to all diagnoses , were in favor of the grade d activity group , although not statistically significant . No effects of the grade d activity intervention were found for functional status or pain . Conclusion : Grade d activity intervention is a valuable strategy to enhance short-term return to work outcomes OBJECTIVE To investigate the effectiveness of a TTM-based motivational counselling approach by trained practice nurses to promote physical activity of low back pain patients in a German primary care setting . METHODS Data were collected in a cluster-r and omized controlled trial with three study arms via question naires and patient interviews at baseline and after 6 and 12 months . We analysed total physical activity and self-efficacy by using r and om effect models to allow for clustering . RESULTS A total of 1378 low back pain patients , many with acute symptoms , were included in the study . Nearly 40 % of all patients reported sufficient physical activity at baseline . While there were significant improvements in patients ' physical activity behaviour in all study arms , there was no evidence for an intervention effect . CONCLUSION The outcome may be explained by insufficient performance of the practice nurses , implementation barriers caused by the German health care system and the heterogenous sample . PRACTICE IMPLICATION S Given the objective to incorporate practice nurses into patient education , there is a need for a better basic training of the nurses and for a change towards an organizational structure that facilitates patient-nurse communication . Counselling for low back pain patients has to consider more specificated aims for different subgroups Study Design . A 5-year prospect i ve cohort study was conducted of men and women seeking care for a new period of low back pain ( LBP ) . Objectives . To study the natural course of pain and disability due to LBP during a 5-year follow-up period , and to investigate the possible influence of regular physical exercise on recovery . Summary of Background Data . LBP is major health problem , but its natural course is not very well studied . Several studies have investigated the role of physical exercise on LBP disorders , with inconsistent results . Methods . At baseline , a total of 790 subjects seeking care for LBP were interviewed about physical exercise during leisure time . Over 5 years , 3 follow-up assessment s were made by postal question naire . At all measuring points , pain intensity ratings and disability scores were compared between men and women , and among 3 exercise categories . Results . The pain intensity and disability scores were improved after 5 years for both men and women . The most prominent improvements occurred after 6 months , but less so thereafter . There were no significant differences between men and women with regard to individual changes at the 5-year follow-up concerning the pain intensity or disability scores . There were no significant differences , either for women or men , between low , median , or high intensity exercise groups regarding pain intensity or disability values for the individual change at the 5-year follow-up . Conclusions . Over a 5-year period , both men and women who had sought care for LBP reported a decrease in pain and disability ; however , only a few were fully restored . In this study , we found no effect of nonspecific physical exercise on recovery from LBP in men and women Study Design . Prospect i ve case series with historical controls ( normative data ) . Objectives . To compare the aerobic fitness level of patients with chronic low back pain ( CLBP ) with healthy controls matched for gender , age , and level of sport activity and to evaluate the association of the difference in aerobic fitness level with pain intensity , duration and degree of disability , fear of injury , and level of activity during work , including household and leisure time . Summary and Background Data . Controversy exists whether patients with CLBP have a lower level of aerobic fitness and whether this level may partly depend on the patients ’ activity level . Methods . A total of 108 CLBP patients completed question naires regarding pain , disability , fear of injury , and activity level  and performed a modified Åstr and submaximal cycling test . The maximum oxygen consumption ( VO2max ) was calculated and compared with normative data . Multiple linear regression analysis was performed with the difference of the level of aerobic fitness as dependent variable . Results . VO2max could be calculated in 78 % of the patients . Both men and women with CLBP had significant lower VO2max than the healthy referents ( 10 mL/kg LBM • min−1 and 5.6 mL/kg LBM • min−1 respectively , P < 0.001 ) , and this difference was significantly greater in men ( P = 0.03 ) . Multiple regression analysis showed that the level of aerobic fitness was not associated with the presumed variables . The patients who stopped the test prematurely were older ( P = 0.02 ) and more disabled ( P = 0.01 ) . Conclusion . CLBP patients , especially men , seem to have a reduced aerobic fitness level compared with the normative population . No explanatory factor for that loss could be identified OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity BACKGROUND AND PURPOSE Therapeutic exercise has been shown to be beneficial in decreasing pain and in increasing functioning in patients with chronic low back pain . However , longitudinal follow-up studies are small in number , and often limited in the numbers of subjects due to drop-outs . In addition there is a shortage of real control groups in most cases . The purpose of the present study was to describe long-term changes in intensity of low back pain and in functioning for two study groups five years after undertaking a home exercise programme . METHOD This was a r and omized follow-up study over five years . Fifty-seven subjects were reassessed with question naires five years after their initial recruitment for an intervention study . A home exercise group ( n = 29 ) , with training once a day , and a control group ( n = 28 ) , without exercise , were included in the present study protocol . The primary outcome measurements included a question naire on the intensity of low back pain ( Borg CR-10 scale ) and on functioning ( Oswestry Disability Index ; ODI ) . The confounding physical activity was controlled with metabolic unit ( MET ) values . RESULTS The CR-10 and ODI scores decreased during the first three months in both study groups . During the follow-ups , the corresponding indicators of the home exercise group remained below baseline values . The CR-10 score was significantly lower in the home exercise group ( p = 0.01 ) during the last five-year follow-up session compared with the control group . Overall physical activity decreased slightly during the five-year follow-up , but there were no differences between the two study groups . CONCLUSIONS The present r and omized study indicates that supervised , controlled home exercises lead to reduced low back pain , and that positive effects were preserved over five years Study Design . Prospect i ve case series with historical controls ( normative data ) . Objectives . To compare aerobic fitness levels in patients with chronic low back pain with those published on a sample of 295 healthy subjects . Summary of Background Data . Clinical belief holds that patients with chronic low back pain have low fitness levels as a result of inactivity because of pain . Because few studies have investigated the level of aerobic fitness in these patients , however , it remains unclear how fitness levels in patients with chronic low back pain patients compare with those published a sample of the normative population . Methods . A sample of 50 patients with chronic low back pain with a mean pain duration of 40 months referred to an outpatient pain clinic performed a  symptom-limited modified tread 
    Output:
    
agent
These data suggest that the activity levels of patients with NSLBP are neither associated with , nor predictive of , disability or pain levels .
***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: Study Design . A population -based cross-sectional and 5-year prospect i ve question naire study . Objective . To investigate self-reported physical workload as a risk factor for low back pain . Summary of Background Data . Both physical and psychosocial workplace factors are considered risk factors for low back pain . However , today no consensus has been reached regarding the exact role of these factors in the genesis of low back pain . Methods . Question naire data were collected at baseline for 1397 ( and after 5 years for 1163 ) men and women aged 31–50 years at baseline .  Low back pain ( “ any low back pain within the past year , ” “ low back pain ≤ 30 days in total during the past year , ” “ low back pain > 30 days in total during the past year ” ) was analyzed in relation to physical workload ( sedentary , light physical , and heavy physical work ) using logistic regression and controlling for age , gender , and social group . The proportions of workers changing between the workload groups over the 5-year period were analyzed in relation to low back pain status . Results . At baseline no statistically significant differences in low back pain outcomes were found for workers exposed to sedentary , light physical , or heavy physical work . This was true for all age , gender , and social groups . At follow-up there was a statistically significant dose – response association between any low back pain and longst and ing low back pain within the past year and increasing physical workload  at baseline also after controlling for age , gender , and social group . Subjects with heavy physical workload at baseline changed statistically significantly more often to sedentary work if they experienced low back pain for more than 30 days out of the past year . Conclusions . Having a sedentary job might have a protective or neutral effect in relation to low back pain , whereas having a heavy physical job constitutes a significant risk factor . Because of migration between exposure groups ( the “ healthy-worker ” effect ) , longitudinal studies are necessary for investigating the associations between physical workload and low back pain Study Design . Prospect i ve cohort study . Objectives . To investigate whether physical performance , grip strength , cognitive function , and depression symptomatology are risk factors for incident low back pain ( LBP ) over a 2-year period in seniors . Summary of Background Data . LBP is common in the older age groups , but little is known about predictors of LBP in this age group . Methods . Data from the 2001 and 2003 data collection from the population -based Longitudinal Study of Aging Danish Twins formed the basis of this analysis . Participants free from LBP at baseline ( no LBP during the past month , N = 1387 ) were included and interview data on overall physical function , and assessment of grip strength , overall cognitive function , and depression at baseline were obtained . LBP status at follow-up was assessed using a modified version of the St and ardized Nordic Question naire . Logistic regression was used to assess the associations between the baseline risk factors and LBP at follow-up . Results . A total of 1387 persons 70 to 100 years of age at baseline were included in the analyses . Of the initially LBP-free individuals , 7 % had experienced LBP more than 30 days out of the past year , 7 % had altered or decreased their physical activities due to LBP , and 11 % had received treatment for LBP at follow-up . Good overall physical function ( being among the top 50 % ) at baseline was protective for LBP of more than 30 days duration and for diminishing physical activities due to LBP and for care seeking due to LBP . High depression scores ( being among the top 25 % ) were strongly associated with altering or decreasing daily activities because of LBP . Grip strength and overall cognitive performance at baseline were associated with lower incidence of LBP and decreasing activities due to LBP at follow-up ; however , these associations were not statistically significant . Conclusion . Poor overall physical function and depression symptomatology are associated with LBP and consequences of LBP in persons 70 years of age and older Introduction : Behaviorally oriented grade d activity interventions have been suggested for sick-listed workers with low back pain on return to work , but have not been extensively evaluated . Methods : One hundred and thirty-four workers were r and omly assigned to either a grade d activity intervention ( n = 67 ) or usual care ( n = 67 ) and followed-up for 12 months . Results : The grade d activity group returned back to work faster with a median of 54 days compared to 67 days in the usual care group . The grade d activity intervention was more effective after approximately 50 days post-r and omization ( HRR = 1.9 , CI = 1.2–3.1 , p = 0.01 ) . Differences between the groups in number of recurrent episodes , total number of days of sick leave due to low back pain , and total number of days of sick leave due to all diagnoses , were in favor of the grade d activity group , although not statistically significant . No effects of the grade d activity intervention were found for functional status or pain . Conclusion : Grade d activity intervention is a valuable strategy to enhance short-term return to work outcomes OBJECTIVE To investigate the effectiveness of a TTM-based motivational counselling approach by trained practice nurses to promote physical activity of low back pain patients in a German primary care setting . METHODS Data were collected in a cluster-r and omized controlled trial with three study arms via question naires and patient interviews at baseline and after 6 and 12 months . We analysed total physical activity and self-efficacy by using r and om effect models to allow for clustering . RESULTS A total of 1378 low back pain patients , many with acute symptoms , were included in the study . Nearly 40 % of all patients reported sufficient physical activity at baseline . While there were significant improvements in patients ' physical activity behaviour in all study arms , there was no evidence for an intervention effect . CONCLUSION The outcome may be explained by insufficient performance of the practice nurses , implementation barriers caused by the German health care system and the heterogenous sample . PRACTICE IMPLICATION S Given the objective to incorporate practice nurses into patient education , there is a need for a better basic training of the nurses and for a change towards an organizational structure that facilitates patient-nurse communication . Counselling for low back pain patients has to consider more specificated aims for different subgroups Study Design . A 5-year prospect i ve cohort study was conducted of men and women seeking care for a new period of low back pain ( LBP ) . Objectives . To study the natural course of pain and disability due to LBP during a 5-year follow-up period , and to investigate the possible influence of regular physical exercise on recovery . Summary of Background Data . LBP is major health problem , but its natural course is not very well studied . Several studies have investigated the role of physical exercise on LBP disorders , with inconsistent results . Methods . At baseline , a total of 790 subjects seeking care for LBP were interviewed about physical exercise during leisure time . Over 5 years , 3 follow-up assessment s were made by postal question naire . At all measuring points , pain intensity ratings and disability scores were compared between men and women , and among 3 exercise categories . Results . The pain intensity and disability scores were improved after 5 years for both men and women . The most prominent improvements occurred after 6 months , but less so thereafter . There were no significant differences between men and women with regard to individual changes at the 5-year follow-up concerning the pain intensity or disability scores . There were no significant differences , either for women or men , between low , median , or high intensity exercise groups regarding pain intensity or disability values for the individual change at the 5-year follow-up . Conclusions . Over a 5-year period , both men and women who had sought care for LBP reported a decrease in pain and disability ; however , only a few were fully restored . In this study , we found no effect of nonspecific physical exercise on recovery from LBP in men and women Study Design . Prospect i ve case series with historical controls ( normative data ) . Objectives . To compare the aerobic fitness level of patients with chronic low back pain ( CLBP ) with healthy controls matched for gender , age , and level of sport activity and to evaluate the association of the difference in aerobic fitness level with pain intensity , duration and degree of disability , fear of injury , and level of activity during work , including household and leisure time . Summary and Background Data . Controversy exists whether patients with CLBP have a lower level of aerobic fitness and whether this level may partly depend on the patients ’ activity level . Methods . A total of 108 CLBP patients completed question naires regarding pain , disability , fear of injury , and activity level  and performed a modified Åstr and submaximal cycling test . The maximum oxygen consumption ( VO2max ) was calculated and compared with normative data . Multiple linear regression analysis was performed with the difference of the level of aerobic fitness as dependent variable . Results . VO2max could be calculated in 78 % of the patients . Both men and women with CLBP had significant lower VO2max than the healthy referents ( 10 mL/kg LBM • min−1 and 5.6 mL/kg LBM • min−1 respectively , P < 0.001 ) , and this difference was significantly greater in men ( P = 0.03 ) . Multiple regression analysis showed that the level of aerobic fitness was not associated with the presumed variables . The patients who stopped the test prematurely were older ( P = 0.02 ) and more disabled ( P = 0.01 ) . Conclusion . CLBP patients , especially men , seem to have a reduced aerobic fitness level compared with the normative population . No explanatory factor for that loss could be identified OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity BACKGROUND AND PURPOSE Therapeutic exercise has been shown to be beneficial in decreasing pain and in increasing functioning in patients with chronic low back pain . However , longitudinal follow-up studies are small in number , and often limited in the numbers of subjects due to drop-outs . In addition there is a shortage of real control groups in most cases . The purpose of the present study was to describe long-term changes in intensity of low back pain and in functioning for two study groups five years after undertaking a home exercise programme . METHOD This was a r and omized follow-up study over five years . Fifty-seven subjects were reassessed with question naires five years after their initial recruitment for an intervention study . A home exercise group ( n = 29 ) , with training once a day , and a control group ( n = 28 ) , without exercise , were included in the present study protocol . The primary outcome measurements included a question naire on the intensity of low back pain ( Borg CR-10 scale ) and on functioning ( Oswestry Disability Index ; ODI ) . The confounding physical activity was controlled with metabolic unit ( MET ) values . RESULTS The CR-10 and ODI scores decreased during the first three months in both study groups . During the follow-ups , the corresponding indicators of the home exercise group remained below baseline values . The CR-10 score was significantly lower in the home exercise group ( p = 0.01 ) during the last five-year follow-up session compared with the control group . Overall physical activity decreased slightly during the five-year follow-up , but there were no differences between the two study groups . CONCLUSIONS The present r and omized study indicates that supervised , controlled home exercises lead to reduced low back pain , and that positive effects were preserved over five years Study Design . Prospect i ve case series with historical controls ( normative data ) . Objectives . To compare aerobic fitness levels in patients with chronic low back pain with those published on a sample of 295 healthy subjects . Summary of Background Data . Clinical belief holds that patients with chronic low back pain have low fitness levels as a result of inactivity because of pain . Because few studies have investigated the level of aerobic fitness in these patients , however , it remains unclear how fitness levels in patients with chronic low back pain patients compare with those published a sample of the normative population . Methods . A sample of 50 patients with chronic low back pain with a mean pain duration of 40 months referred to an outpatient pain clinic performed a  symptom-limited modified tread 
    Output:
    