***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: BACKGROUND Studies in many countries have reported higher lung cancer incidence and mortality in individuals with lower socioeconomic status . METHODS To investigate the role of smoking in these inequalities , we used data from 391,251 participants in the European Prospect i ve Investigation into Cancer and Nutrition study , a cohort of individuals in 10 European countries . We collected information on smoking ( history and quantity ) , fruit and vegetable consumption , and education through question naires at study entry and gathered data on lung cancer incidence for a mean of 8.4 years . Socioeconomic status was defined as the highest attained level of education , and participants were grouped by sex and region of residence ( Northern Europe , Germany , or Southern Europe ) . Relative indices of ine quality ( RIIs ) of lung cancer risk unadjusted and adjusted for smoking were estimated using Cox regression models . Additional analyses were performed by histological type . RESULTS During the study period , 939 men and 692 women developed lung cancer .  Inequalities in lung cancer risk ( RII(men ) = 3.62 , 95 % confidence interval [ CI ] = 2.77 to 4.73 , 117 vs 52 per 100,000 person-years for lowest vs highest education level ; RII(women ) = 2.39 , 95 % CI = 1.77 to 3.21 , 46 vs 25 per 100,000 person-years ) decreased after adjustment for smoking but remained statistically significant ( RII(men ) = 2.29 , 95 % CI = 1.75 to 3.01 ; RII(women ) = 1.59 , 95 % CI = 1.18 to 2.13 ) . Large RIIs were observed among men and women in Northern European countries and among men in Germany , but inequalities in lung cancer risk were reverse ( RIIs < 1 ) among women in Southern European countries . Inequalities differed by histological type . Adjustment for smoking reduced inequalities similarly for all histological types and among men and women in all regions . In all analysis , further adjustment for fruit and vegetable consumption did not change the estimates . CONCLUSION Self-reported smoking consistently explains approximately 50 % of the inequalities in lung cancer risk due to differences in education Effects of age , sex , race , and initial fitness on training responses of maximal O(2 ) uptake ( VO(2 max ) ) are unclear . Data were available on 435 whites and 198 blacks ( 287 men and 346 women ) , aged 17 - 65 yr , before and after st and ardized cycle ergometer training .  Individual responses varied widely , but VO(2 max ) increased significantly for all groups . Responses by men and women and by blacks and whites of all ages varied widely . There was no sex difference for change ( Delta ) in VO(2 max ) ( ml . kg(-1 ) . min(-1 ) ) ; women had lower initial values and greater relative ( % ) increases . Blacks began with lower values but had similar responses . Older subjects had a lower Delta but a similar percent change . Baseline VO(2 max ) correlated nonsignificantly with DeltaVO(2 max ) but significantly with percent change . There were high , medium , and low responders in all age groups , both sexes , both races , and all levels of initial fitness . Age , sex , race , and initial fitness have little influence on VO(2 max ) response to st and ardized training in a large heterogeneous sample of sedentary black and white men and women This study examined the influence of childhood socioeconomic position ( SEP ) and social mobility on activity and fitness tracking from childhood into adulthood . In a prospect i ve cohort of 2,185 Australian adults ( aged 26 - 36 years ) , first examined in 1985 ( at ages 7 - 15 years ) , self-reported physical activity and cardiorespiratory fitness ( sub sample only ) were measured .  SEP  measures included retrospectively reported parental education ( baseline ) and own education ( follow-up ) . There was little evidence of a relation between childhood SEP and activity tracking , but high childhood SEP  ( maternal education ) was associated with a 59 % increased likelihood of persistent fitness , and medium childhood SEP  ( paternal and parental education ) was associated with a 33%-36 % decreased likelihood of persistent fitness . Upward social mobility was associated with a greater likelihood of increasing activity ( 38%-49 % ) and fitness ( 90 % ) , and persistently high SEP was associated with a greater likelihood of increasing activity ( males : 58 % ) and fitness ( males and females combined : 89 % ) . In conclusion , persistently high SEP and upward social mobility were associated with increases in activity and fitness from childhood to adulthood . Findings highlight socioeconomic differentials in activity and fitness patterns and suggest that improvements in education may represent a pathway through which physical activity levels can be increased and health benefits achieved The effects of 12 weeks of home-based exercise training on peak oxygen consumption ( VO2 max ) in healthy sedentary middle-aged men , mean age 49 + /- 6 years , were evaluated . Twenty-one men trained at low intensity , 23 trained at high intensity and 20 were control subjects .  Individually prescribed low- and high-intensity training was performed 5 times per week within a range of 42 to 60 % and 63 to 81 % of baseline VO2 max , corresponding to average heart rates of 102 to 122 and 128 to 148 beats/min , respectively . Caloric expenditure per training session approximated 350 kcal in both groups ; adherence was at least 90 % in both groups . VO2 max increased 8 % in patients who trained at low intensity , 17 % in those who trained at high intensity ( both p less than 0.001 ) , and not at all in control subjects . Low-intensity exercise training at home significantly augments functional capacity in healthy sedentary middle-aged men OBJECTIVES The combination of high physical work dem and s and low physical capacity has been shown to increase the risk for cardiovascular disease and musculoskeletal disorders . The aim of this study was to assess the physical capacity of construction workers and evaluate the effect of individually tailored exercise programs on their physical fitness and muscular capacity . METHOD The study was a r and omized controlled trial of male constructions workers allocated to either an exercise or control group . The intervention lasted 12 weeks , and the exercise group trained 3 x 20 minutes a week . The participants completed health checks before and after the intervention period . Data from the first health check were used to tailor the exercise in the interventions . RESULTS At baseline , participants had maximal oxygen consumption ( VO(2max ) ) of 2.9 [ st and ard deviation ( SD ) 0.7 ] l/min and body mass index ( BMI ) of 28.3 ( SD 4.7 ) . Compared to representative data on employees in Denmark ( N=78 ) , this study population ( N=67 ) had significantly lower relative aerobic capacity [ difference in z-score -1.13 , st and ard error ( SE ) 0.1 , P<0.001 ] and higher BMI [ difference in z-score 1.10 , SE 0.2 , P<0.001 ] at baseline . With respect to the intervention , group x time analyses showed a significant difference in estimated change in VO(2max)of 0.4 l/min for the exercise group and 0.0 l/min for the control group ( P<0.001 ) . Body mass and other general health measures remained unchanged . CONCLUSION Training for 20 minutes , 3 times a week significantly increased VO(2max)with a clinical ly relevant magnitude regarding risk of cardiometabolic disorders . This study demonstrates a good effectiveness for integrating short exercise bouts into organizational routines among constructions workers OBJECTIVE To evaluate the relationship between changes in physical fitness and  risk of mortality in men . DESIGN Prospect i ve study , with two clinical examinations ( mean interval between examinations , 4.9 years ) to assess change or lack of change in physical fitness as associated with risk of mortality during follow-up after the subsequent examination ( mean follow-up from subsequent examination , 5.1 years ) . SETTING Preventive medicine clinic . STUDY PARTICIPANTS Participants were 9777 men given two preventive medical examinations  , each of which included assessment of physical fitness by maximal exercise tests and evaluation of health status . MAIN OUTCOME MEASURES All cause ( n = 223 ) and cardiovascular disease ( n = 87 ) mortality . RESULTS The highest age-adjusted all-cause death rate was observed in men who were unfit at both examinations ( 122.0/10,000 man-years ) ; the lowest death rate was in men who were physically fit at both examinations ( 39.6/10,000 man-years ) . Men who improved from unfit to fit between the first and subsequent examinations had an age-adjusted death rate of 67.7/10,000 man-years . This is a reduction in mortality risk of 44 % ( 95 % confidence interval , 25 % to 59 % ) relative to men who remained unfit at both examinations . Improvement in fitness was associated with lower death rates after adjusting for age , health status , and other risk factors of premature mortality . For each minute increase in maximal treadmill time between examinations , there was a corresponding 7.9 % ( P = .001 ) decrease in risk of mortality . Similar results were seen when the group was stratified by health status , and for cardiovascular disease mortality . CONCLUSIONS Men who maintained or improved adequate physical fitness were less likely to die from all causes and from cardiovascular disease during follow-up than persistently unfit men . Physicians should encourage unfit men to improve their fitness by starting a physical activity program This study was design ed to investigate the effect of exercise intensity on cardiorespiratory fitness and coronary heart disease risk factors . Maximum oxygen consumption ( Vo(2 max ) ) , lipid , lipoprotein , and fibrinogen concentrations were measured in 64 previously sedentary men before r and om allocation to a nonexercise control group , a moderate-intensity exercise group ( three 400-kcal sessions per week at 60 % of Vo(2 max ) ) , or a high-intensity exercise group ( three 400-kcal sessions per week at 80 % of Vo(2 max ) ) . Subjects were instructed to maintain their normal dietary habits , and training heart rates were represcribed after monthly fitness tests . Forty-two men finished the study . After 24 wk , Vo(2 max ) increased by 0.38 + /- 0.14 l/min in the moderate-intensity group and by 0.55 + /- 0.27 l/min in the high-intensity group . Repeated- measures analysis of variance identified a significant interaction between monthly Vo(2 max ) score and exercise group ( F = 3.37 , P < 0.05 ) , indicating that Vo(2 max ) responded differently to moderate- and high-intensity exercise . Trend analysis showed that total cholesterol , low-density lipoprotein cholesterol , non-high-density lipoprotein cholesterol , and fibrinogen concentrations changed favorably across control , moderate-intensity , and high-intensity groups . However , significant changes in total cholesterol ( -0.55 + /- 0.81 mmol/l ) , low-density lipoprotein cholesterol ( -0.52 + /- 0.80 mmol/l ) , and non-high-density lipoprotein cholesterol ( -0.54 + /- 0.86 mmol/l ) were only observed in the high-intensity group ( all P < 0.05 vs. controls ) . These data suggest that high-intensity training is more effective in improving cardiorespiratory fitness than moderate-intensity training of equal energy cost . These data also suggest that changes in coronary heart disease risk factors are influenced by exercise intensity A number of cross-sectional and prospect i ve studies that compared the insulin sensitivity of various national and ethnic population s within the U.S. to the total U.S. population were analyzed to find possible risk factors for the development of type 2 diabetes . It was found that the risks for diabetes in African-Americans , Hispanics , and Native Americans are approximately 2 , 2.5 , and 5 times greater , respectively , than in Caucasians . Studies of the prevalence of type 2 diabetes in Mexican Americans and non-Hispanic whites in San Antonio showed that there is an inverse relationship between socioeconomic status and the prevalence of diabetes . It also appears that cultural effects lead to an increased incidence of obesity in these population s , which may lead to insulin resistance . Genetic factors may also be a contributing factor . A 5-year , prospect i ve study of insulin resistance in Pima Indians showed a relationship between impaired glucose tolerance and subsequent development of type 2 diabetes . In a 7-year study in Mexican Americans , those subjects who had both high insulin secretion and impaired insulin sensitivity had a 14-fold increased risk of developing type 2 diabetes . Regardless of cultural and ethnic factors , the San Antonio Heart Study , which compared Mexican Americans and non-Hispanic whites , showed that in both groups , the strongest predictors of developing type 2 diabetes are elevated fasting insulin concentrations and low insulin secretion The assessment of physical activity at a single time to evaluate its association with cancer may be limited , since such a measure may not adequately reflect activity over the long term . To overcome this limitation , we studied 17,148 Harvard alumni aged 30 - 79 years who were followed prospect ively for the occurrence of colon cancer ( n = 225 ) and rectal cancer 
    Output:
    
Adjustment for PA did not significantly impact the association between education and CRF .
Conclusions There is fair evidence for an association between high levels of education and increased CRF .