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: Data from a community-based four-year prospect i ve study were used to test the hypothesis that heavy physical work is a stronger predictor of  low back pain in smokers than in non-smokers . Of 708 working responders without low back pain during the entire year prior to 1990 , 562 ( 79 % ) completed a question naire four years later in 1994 . A job involving heavy lifting and much st and ing in 1990 was a strong predictor of low back pain in smokers four years later [ odds ratio ( OR ) = 5.53 , 95 % confidence interval ( CI ) = 1.93 - 15.84 , p < 0.01 ) after having adjusted for other job characteristics , demographic factors , emotional symptoms , physical exercise and musculoskeletal pain elsewhere . In non-smokers , having a job with heavy lifting and much st and ing was not associated with low back pain . One explanation may be that smoking leads to reduced perfusion and malnutrition of tissues in or around the spine and causes these tissues to respond inefficiently to mechanical stress OBJECTIVES To identify risk factors for back pain leading to restricted activity ( restricting back pain ) in older persons . DESIGN Prospect i ve cohort study . SETTING Greater New Haven , Connecticut . PARTICIPANTS A total of 731 men and women aged 70 years or older , who were community living and nondisabled in essential activities of daily living at baseline . MEASUREMENTS C and i date risk factors were ascertained every 18 months for 108 months during comprehensive home-based assessment s.  Restricting back pain  was assessed during monthly telephone interviews for up to 126 months . Incident episodes of ( 1 ) short-term ( 1 episode lasting 1 month ) restricting back pain ; and ( 2 ) persistent ( 1 episode lasting 2 or more months ) or recurrent ( 2 or more episodes of any duration ) restricting back pain were determined during each 18-month interval . The associations between the c and i date risk factors and short-term and persistent/recurrent restricting back pain , respectively , were evaluated using a multivariable Cox model . RESULTS The cumulative incidence was 21.3 % ( 95 % confidence interval [ CI ] 19.6%-23.1 % ) for short-term restricting back pain and 20.6 % ( CI 18.6%-22.9 % ) for persistent/recurrent restricting back pain over a median follow-up of 109 months . In a recurrent event multivariable analysis , female sex ( hazard ratio [ HR ] 1.30 ; 1.07 - 1.58 ) , weak grip strength ( HR 1.24 ; 1.01 - 1.52 ) , and hip weakness ( HR 1.19 ; 1.07 - 1.32 ) were independently associated with an increased likelihood of having short-term restricting back pain , whereas female sex ( HR 1.48 ; CI 1.13 - 1.94 ) , depressive symptoms ( HR 1.57 ; 1.23 - 2.00 ) , 2 or more chronic conditions ( HR 1.38 ; 1.08 - 1.77 ) , and arthritis ( HR 1.66 ; 1.31 - 2.09 ) were independently associated with persistent/recurrent restricting back pain . CONCLUSION In this prospect i ve study , several factors were independently associated with restricting back pain , including some that may be modifiable and therefore potential targets for interventions to reduce this common and often recurrent condition in older persons OBJECTIVE All occupations expose workers to varied and unique conditions . The nature of work has been recognized as influencing the health of workers . Whether predictors for chronic neck and low back pain would be occupation-specific is unknown . This study aim ed to identify predictors for chronic neck and low back pain in a cohort of office workers . METHODS A prospect i ve study was carried out among 669 healthy office workers . At baseline , risk factors were assessed using a question naire and st and ardized physical examination . A symptomatic case was defined as an individual who reported pain greater than 30 mm on a 100-mm VAS , and chronic pain was defined as experiencing ongoing neck or low back pain for greater than 3 months over the past 6 months . Two regression models were built to analyze the risk factors for developing chronic neck and low back pain . RESULTS Of the sample , 17 and 27 % of office workers who reported a new onset of neck or low back pain developed chronicity , respectively . Predictors for chronic neck pain were high body mass index , frequent neck extension during the work day , high initial pain intensity , and high psychological job dem and s. The development of chronic low back pain was associated with history of low back pain and high initial pain intensity . CONCLUSIONS The findings suggest that predictors for chronic musculoskeletal pain in a sub population may be a subset of predictors identified in a general population or occupation specific . Successful management to prevent chronic musculoskeletal pain may also need to consider the patient 's occupation BACKGROUND CONTEXT Association between low physical fitness and  low back pain ( LBP ) is contradictory in previous studies . PURPOSE The objective of the present prospect i ve cohort study was to investigate the predictive associations of various intrinsic risk factors in young conscripts for LBP , with special attention to physical fitness . STUDY DESIGN A prospect i ve cohort study . PATIENT SAMPLE A representative sample of Finnish male conscripts . In Finl and , military service is compulsory for male citizens and 90 % of young men enter into the service . OUTCOME MEASURES Incidence of LBP and recurrent LBP prompting a visit at the garrison health clinic during 6-month military training . METHODS Four successive cohorts of 18- to 28-year-old male conscripts ( N=982 ) were followed for 6 months . Conscripts with incidence of LBP were identified and treated at the garrison clinic . Predictive associations between intrinsic risk factors and LBP were examined using multivariate Cox proportional hazard models . RESULTS The cumulative incidence of LBP was 16 % , the incidence rate being 1.2 ( 95 % confidence interval [ CI ] , 1.0 - 1.4 ) per 1,000 person-days . Conscripts with low educational level had increased risk for incidence of LBP ( hazard ratio [ HR ] , 1.6 ; 95 % CI , 1.1 - 2.3 ) . Conscripts with low dynamic trunk muscle endurance and low aerobic endurance simultaneously ( ie , having coimpairment ) at baseline also had an increased risk for incidence of LBP . The strongest risk factor was coimpairment of trunk muscular endurance in tests of back lift and push-up ( HR , 2.8 ; 95 % CI , 1.4 - 5.9 ) . CONCLUSIONS The increased risk for LBP was observed among young men who had a low educational level and poor fitness level in both muscular and aerobic performance Purpose To investigate whether depression symptomatology is associated with low back pain ( LBP ) in twins aged 70 + and whether this effect depends on a person ’s physical activity ( PA ) status . Methods This prospect i ve cohort and nested case – control study used a nationally representative sample of twins . Data on depression symptomatology ( modified Cambridge Mental Disorders Examination ) and  self-reported PA were obtained from the Longitudinal Study of Aging Danish Twins using twins without LBP at baseline . Associations between depression symptomatology ( highest quartile ) at baseline and LBP two years later were investigated using logistic regression analyses adjusted for sex . To examine the moderating effect of PA , we tested its interaction with depression . Associations were analysed using the complete sample of 2446 twins and a matched case – control analysis of 97 twin pairs discordant for LBP at follow-up . Odds ratios ( OR ) with 95 % confidence intervals ( CI ) were calculated . Results Using the whole sample , high depression scores were associated with an increased probability of LBP ( OR 1.56 , 95 % CI 1.22–1.99 , P ≤ 0.01 ) . There was no statistically significant interaction of light PA and depression symptomatology ( OR 0.78 , 95 % CI 0.46–1.35 , P = 0.39 ) and strenuous PA and depression symptomatology ( 0.84 , 95 % CI 0.50–1.41 , P = 0.51 ) . The case – control analysis showed similar ORs , although statistically insignificant . Conclusions High depression symptomatology predicted incident LBP . This effect is supposedly not attributable to genetic or shared environmental factors . Physical activity did not moderate the effect of depression symptomatology on LBP STUDY OBJECTIVE : To explore the previously stated hypothesis that risk factors for atherothrombotic disease are associated with back pain . DESIGN : Prospect i ve ( mean of four years of follow up ) and retrospective analyses using two main outcome measures : ( a ) short ( < or = 7 days ) and long ( > 7 days ) spells of sickness absence because of back pain reported separately in men and women ; ( b ) consistency of effect across the result ing four duration of spell and sex cells . SETTING : 14 civil service departments in London . PARTICIPANTS : 3506 male and 1380 female white office-based civil servants , aged 35 - 55 years at baseline . MAIN RESULTS : In age adjusted models , low apo AI was associated with back pain across all four duration -sex cells and smoking was associated across three cells . Six factors were associated with back pain in two cells : low exercise and high BMI , waist-hip ratio , triglycerides , insulin and Lp(a ) . On full adjustment ( for age , BMI , employment grade and back pain at baseline ) , each of these factors retained a statistically significant effect in at least one duration -sex cell . Triglycerides were associated with short and long spells of sickness absence because of back pain in men in fully adjusted models with rate ratios ( 95 % confidence intervals ) of 1.53 ( 1.1 , 2.1 ) and 1.75 ( 1.0 , 3.2 ) respectively . There was little or no evidence of association in age adjusted models with : fibrinogen , glucose tolerance , total cholesterol , apoB , hypertension , factor VII , von Willebr and factor , electrocardiographic evidence of coronary heart disease and reported angina . CONCLUSIONS : In this population of office workers , only modest support was found for an atherothrombotic component to back pain sickness absence . However , the young age of participants at baseline and the lack of distinction between different types of back pain are likely to bias the findings toward null . Further research is required to ascertain whether a population sub-group of atherothrombotic back pain can be identified Introduction . The aim of the present study was to determine the closeness of agreement between a self-reported and an objective measure of physical activity in low back pain patients and healthy controls . Beyond , influencing factors on overestimation were identified . Methods . 27 low back pain patients and 53 healthy controls wore an accelerometer ( objective measure ) for seven consecutive days and answered a question naire on physical activity ( self-report ) over the same period of time . Differences between self-reported and objective data were tested by Wilcoxon test . Bl and -Altman analysis was conducted for describing the closeness of agreement . Linear regression models were calculated to identify the influence of age , sex , and body mass index on the overestimation by self-report . Results . Participants overestimated self-reported moderate activity in average by 42 min/day ( p = 0.003 ) and vigorous activity by 39 min/day ( p < 0.001 ) . Self-reported sedentary time was underestimated by 122 min/day ( p < 0.001 ) . No individual-related variables influenced the overestimation of physical activity .  Low back pain patients were more likely to underestimate sedentary time compared to healthy controls . Discussion . In rehabilitation and health promotion , the application-oriented measurement of physical activity remains a challenge . The present results contradict other studies that had identified an influence of age , sex , and body mass index on the overestimation of physical activity Study Design . Prospect i ve cohort study of twins . Objectives . To investigate associations between physical activity , physical function , and incident low back pain ( LBP ) in an elderly population . Summary of Background Data . The relationship between an active lifestyle and LBP in seniors is unknown . Methods . Participants in the population -based Longitudinal Study of Aging Danish Twins free from LBP at baseline ( no LBP during the past month ) were included , and interview data on physical activity , overall physical function , and LBP at baseline and follow-up were obtained . Associations between levels of  physical activity and LBP were estimated using logistic regression for the entire cohort , and using a matched case-control design for twin pairs discordant for physical activity . Absolute risk and relative risks for incident LBP in relation to physical activity were calculated for participants with higher or lower than average physical function at baseline . Absolute risk for LBP was also calculated for participants based on whether they remained active or inactive between baseline and follow-up or changed activity level . Results . A total of 1387 persons aged 70–100 at baseline were included in the analyses , including 86 twin pairs discordant for physical activity at baseline . In the total sample , 83 % were engaged in light physical activity  , and 42 % of men and 35 % of women were engaged in strenuous  physical activity  at least weekly . Being engaged in strenuous physical activity at baseline was strongly protective in relation to both having had any LBP ( odds ratio 0.21 , 95 % confidence interval 0.12–0.37 for intra-pair analysis ) and having had LBP lasting more than 30 days altogether during the 
    Output:
    
agent
Conclusions Leisure time physical activity may reduce the risk of chronic LBP by 11%–16 % .
***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: Data from a community-based four-year prospect i ve study were used to test the hypothesis that heavy physical work is a stronger predictor of  low back pain in smokers than in non-smokers . Of 708 working responders without low back pain during the entire year prior to 1990 , 562 ( 79 % ) completed a question naire four years later in 1994 . A job involving heavy lifting and much st and ing in 1990 was a strong predictor of low back pain in smokers four years later [ odds ratio ( OR ) = 5.53 , 95 % confidence interval ( CI ) = 1.93 - 15.84 , p < 0.01 ) after having adjusted for other job characteristics , demographic factors , emotional symptoms , physical exercise and musculoskeletal pain elsewhere . In non-smokers , having a job with heavy lifting and much st and ing was not associated with low back pain . One explanation may be that smoking leads to reduced perfusion and malnutrition of tissues in or around the spine and causes these tissues to respond inefficiently to mechanical stress OBJECTIVES To identify risk factors for back pain leading to restricted activity ( restricting back pain ) in older persons . DESIGN Prospect i ve cohort study . SETTING Greater New Haven , Connecticut . PARTICIPANTS A total of 731 men and women aged 70 years or older , who were community living and nondisabled in essential activities of daily living at baseline . MEASUREMENTS C and i date risk factors were ascertained every 18 months for 108 months during comprehensive home-based assessment s.  Restricting back pain  was assessed during monthly telephone interviews for up to 126 months . Incident episodes of ( 1 ) short-term ( 1 episode lasting 1 month ) restricting back pain ; and ( 2 ) persistent ( 1 episode lasting 2 or more months ) or recurrent ( 2 or more episodes of any duration ) restricting back pain were determined during each 18-month interval . The associations between the c and i date risk factors and short-term and persistent/recurrent restricting back pain , respectively , were evaluated using a multivariable Cox model . RESULTS The cumulative incidence was 21.3 % ( 95 % confidence interval [ CI ] 19.6%-23.1 % ) for short-term restricting back pain and 20.6 % ( CI 18.6%-22.9 % ) for persistent/recurrent restricting back pain over a median follow-up of 109 months . In a recurrent event multivariable analysis , female sex ( hazard ratio [ HR ] 1.30 ; 1.07 - 1.58 ) , weak grip strength ( HR 1.24 ; 1.01 - 1.52 ) , and hip weakness ( HR 1.19 ; 1.07 - 1.32 ) were independently associated with an increased likelihood of having short-term restricting back pain , whereas female sex ( HR 1.48 ; CI 1.13 - 1.94 ) , depressive symptoms ( HR 1.57 ; 1.23 - 2.00 ) , 2 or more chronic conditions ( HR 1.38 ; 1.08 - 1.77 ) , and arthritis ( HR 1.66 ; 1.31 - 2.09 ) were independently associated with persistent/recurrent restricting back pain . CONCLUSION In this prospect i ve study , several factors were independently associated with restricting back pain , including some that may be modifiable and therefore potential targets for interventions to reduce this common and often recurrent condition in older persons OBJECTIVE All occupations expose workers to varied and unique conditions . The nature of work has been recognized as influencing the health of workers . Whether predictors for chronic neck and low back pain would be occupation-specific is unknown . This study aim ed to identify predictors for chronic neck and low back pain in a cohort of office workers . METHODS A prospect i ve study was carried out among 669 healthy office workers . At baseline , risk factors were assessed using a question naire and st and ardized physical examination . A symptomatic case was defined as an individual who reported pain greater than 30 mm on a 100-mm VAS , and chronic pain was defined as experiencing ongoing neck or low back pain for greater than 3 months over the past 6 months . Two regression models were built to analyze the risk factors for developing chronic neck and low back pain . RESULTS Of the sample , 17 and 27 % of office workers who reported a new onset of neck or low back pain developed chronicity , respectively . Predictors for chronic neck pain were high body mass index , frequent neck extension during the work day , high initial pain intensity , and high psychological job dem and s. The development of chronic low back pain was associated with history of low back pain and high initial pain intensity . CONCLUSIONS The findings suggest that predictors for chronic musculoskeletal pain in a sub population may be a subset of predictors identified in a general population or occupation specific . Successful management to prevent chronic musculoskeletal pain may also need to consider the patient 's occupation BACKGROUND CONTEXT Association between low physical fitness and  low back pain ( LBP ) is contradictory in previous studies . PURPOSE The objective of the present prospect i ve cohort study was to investigate the predictive associations of various intrinsic risk factors in young conscripts for LBP , with special attention to physical fitness . STUDY DESIGN A prospect i ve cohort study . PATIENT SAMPLE A representative sample of Finnish male conscripts . In Finl and , military service is compulsory for male citizens and 90 % of young men enter into the service . OUTCOME MEASURES Incidence of LBP and recurrent LBP prompting a visit at the garrison health clinic during 6-month military training . METHODS Four successive cohorts of 18- to 28-year-old male conscripts ( N=982 ) were followed for 6 months . Conscripts with incidence of LBP were identified and treated at the garrison clinic . Predictive associations between intrinsic risk factors and LBP were examined using multivariate Cox proportional hazard models . RESULTS The cumulative incidence of LBP was 16 % , the incidence rate being 1.2 ( 95 % confidence interval [ CI ] , 1.0 - 1.4 ) per 1,000 person-days . Conscripts with low educational level had increased risk for incidence of LBP ( hazard ratio [ HR ] , 1.6 ; 95 % CI , 1.1 - 2.3 ) . Conscripts with low dynamic trunk muscle endurance and low aerobic endurance simultaneously ( ie , having coimpairment ) at baseline also had an increased risk for incidence of LBP . The strongest risk factor was coimpairment of trunk muscular endurance in tests of back lift and push-up ( HR , 2.8 ; 95 % CI , 1.4 - 5.9 ) . CONCLUSIONS The increased risk for LBP was observed among young men who had a low educational level and poor fitness level in both muscular and aerobic performance Purpose To investigate whether depression symptomatology is associated with low back pain ( LBP ) in twins aged 70 + and whether this effect depends on a person ’s physical activity ( PA ) status . Methods This prospect i ve cohort and nested case – control study used a nationally representative sample of twins . Data on depression symptomatology ( modified Cambridge Mental Disorders Examination ) and  self-reported PA were obtained from the Longitudinal Study of Aging Danish Twins using twins without LBP at baseline . Associations between depression symptomatology ( highest quartile ) at baseline and LBP two years later were investigated using logistic regression analyses adjusted for sex . To examine the moderating effect of PA , we tested its interaction with depression . Associations were analysed using the complete sample of 2446 twins and a matched case – control analysis of 97 twin pairs discordant for LBP at follow-up . Odds ratios ( OR ) with 95 % confidence intervals ( CI ) were calculated . Results Using the whole sample , high depression scores were associated with an increased probability of LBP ( OR 1.56 , 95 % CI 1.22–1.99 , P ≤ 0.01 ) . There was no statistically significant interaction of light PA and depression symptomatology ( OR 0.78 , 95 % CI 0.46–1.35 , P = 0.39 ) and strenuous PA and depression symptomatology ( 0.84 , 95 % CI 0.50–1.41 , P = 0.51 ) . The case – control analysis showed similar ORs , although statistically insignificant . Conclusions High depression symptomatology predicted incident LBP . This effect is supposedly not attributable to genetic or shared environmental factors . Physical activity did not moderate the effect of depression symptomatology on LBP STUDY OBJECTIVE : To explore the previously stated hypothesis that risk factors for atherothrombotic disease are associated with back pain . DESIGN : Prospect i ve ( mean of four years of follow up ) and retrospective analyses using two main outcome measures : ( a ) short ( < or = 7 days ) and long ( > 7 days ) spells of sickness absence because of back pain reported separately in men and women ; ( b ) consistency of effect across the result ing four duration of spell and sex cells . SETTING : 14 civil service departments in London . PARTICIPANTS : 3506 male and 1380 female white office-based civil servants , aged 35 - 55 years at baseline . MAIN RESULTS : In age adjusted models , low apo AI was associated with back pain across all four duration -sex cells and smoking was associated across three cells . Six factors were associated with back pain in two cells : low exercise and high BMI , waist-hip ratio , triglycerides , insulin and Lp(a ) . On full adjustment ( for age , BMI , employment grade and back pain at baseline ) , each of these factors retained a statistically significant effect in at least one duration -sex cell . Triglycerides were associated with short and long spells of sickness absence because of back pain in men in fully adjusted models with rate ratios ( 95 % confidence intervals ) of 1.53 ( 1.1 , 2.1 ) and 1.75 ( 1.0 , 3.2 ) respectively . There was little or no evidence of association in age adjusted models with : fibrinogen , glucose tolerance , total cholesterol , apoB , hypertension , factor VII , von Willebr and factor , electrocardiographic evidence of coronary heart disease and reported angina . CONCLUSIONS : In this population of office workers , only modest support was found for an atherothrombotic component to back pain sickness absence . However , the young age of participants at baseline and the lack of distinction between different types of back pain are likely to bias the findings toward null . Further research is required to ascertain whether a population sub-group of atherothrombotic back pain can be identified Introduction . The aim of the present study was to determine the closeness of agreement between a self-reported and an objective measure of physical activity in low back pain patients and healthy controls . Beyond , influencing factors on overestimation were identified . Methods . 27 low back pain patients and 53 healthy controls wore an accelerometer ( objective measure ) for seven consecutive days and answered a question naire on physical activity ( self-report ) over the same period of time . Differences between self-reported and objective data were tested by Wilcoxon test . Bl and -Altman analysis was conducted for describing the closeness of agreement . Linear regression models were calculated to identify the influence of age , sex , and body mass index on the overestimation by self-report . Results . Participants overestimated self-reported moderate activity in average by 42 min/day ( p = 0.003 ) and vigorous activity by 39 min/day ( p < 0.001 ) . Self-reported sedentary time was underestimated by 122 min/day ( p < 0.001 ) . No individual-related variables influenced the overestimation of physical activity .  Low back pain patients were more likely to underestimate sedentary time compared to healthy controls . Discussion . In rehabilitation and health promotion , the application-oriented measurement of physical activity remains a challenge . The present results contradict other studies that had identified an influence of age , sex , and body mass index on the overestimation of physical activity Study Design . Prospect i ve cohort study of twins . Objectives . To investigate associations between physical activity , physical function , and incident low back pain ( LBP ) in an elderly population . Summary of Background Data . The relationship between an active lifestyle and LBP in seniors is unknown . Methods . Participants in the population -based Longitudinal Study of Aging Danish Twins free from LBP at baseline ( no LBP during the past month ) were included , and interview data on physical activity , overall physical function , and LBP at baseline and follow-up were obtained . Associations between levels of  physical activity and LBP were estimated using logistic regression for the entire cohort , and using a matched case-control design for twin pairs discordant for physical activity . Absolute risk and relative risks for incident LBP in relation to physical activity were calculated for participants with higher or lower than average physical function at baseline . Absolute risk for LBP was also calculated for participants based on whether they remained active or inactive between baseline and follow-up or changed activity level . Results . A total of 1387 persons aged 70–100 at baseline were included in the analyses , including 86 twin pairs discordant for physical activity at baseline . In the total sample , 83 % were engaged in light physical activity  , and 42 % of men and 35 % of women were engaged in strenuous  physical activity  at least weekly . Being engaged in strenuous physical activity at baseline was strongly protective in relation to both having had any LBP ( odds ratio 0.21 , 95 % confidence interval 0.12–0.37 for intra-pair analysis ) and having had LBP lasting more than 30 days altogether during the 
    Output:
    