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: Background PTCA is performed primarily to improve health-related quality of life ( HRQOL ) in patients with symptomatic coronary artery disease . In patients undergoing PTCA , smoking has been shown to increase risks of late myocardial infa rct ion and death . Whether smoking also affects HRQOL after PTCA is currently unknown . Methods and Results We examined the relation between smoking status and HRQOL among 1432 patients who underwent PTCA as part of 2 multicenter clinical trials . HRQOL was assessed with the use of the Medical Outcomes Study SF-36 question naire . Patients were classified as smokers ( n=301 ) , quitters ( n=141 ) , or nonsmokers ( n=990 ) on the basis of their smoking status at the time of their index procedure and during the first year of follow-up . For the overall population , HRQOL improved significantly after PTCA for all scales except general health perception , with improvements ranging from 5.5 points for mental health to 23.2 points for role-physical functioning . After adjustment for baseline characteristics and initial HRQOL , nonsmokers had gains at 6 months that were larger than those of smokers for all health domains : physical function ( 15.4 versus 10.4 points ) , role-physical ( 24.5 versus 13.9 ) , pain ( 18.4 versus 13.3 ) , general health perception ( 1.7 versus −4.5 ) , vitality ( 11.0 versus 4.7 ) , social function ( 12.8 versus 3.5 ) , role-emotional ( 13.5 versus 6.7 ) , and mental health ( 6.8 versus 0.8;P < 0.02 for all comparisons ) . Quitters had 6-month HRQOL improvements that were greater than those in smokers for all domains as well . Findings were similar at 1 year . Conclusions Quality -of-life benefits of PTCA are diminished by continued smoking . Efforts to promote smoking cessation at the time of PTCA may substantially improve the health outcomes of these procedures STUDY OBJECTIVE --To examine the effect on mortality of stopping smoking after myocardial infa rct ion and the psychosocial factors that influence the decision to stop . DESIGN -- Analysis of smokers in a large prospect i ve study . Self completed question naires provided information on psychosocial factors . SETTING --Coronary care units at six English hospitals participating in a multicentre clinical trial . SUBJECTS -- These comprised consenting myocardial infa rct ion survivors who had been identified as smokers and who completed question naires within seven days of infa rct at six hospitals participating in the Anglo-Sc and inavian study of early thrombolysis . The 532 patients identified have been followed for over five and a half years . The main outcome measure was five year all cause mortality . MAIN RESULTS --Smokers who stopped within one month showed significantly reduced mortality compared with those who persisted , adjusting for other prognostic indicators ( odds ratio 0.56 , 95 % confidence interval 0.33 , 0.98 ) . Overall , 74 % stopped smoking . Being married , low life stress levels before infa rct , and higher social class were associated with stopping smoking but the differentials were small . Of the clinical variables , a final diagnosis of definite myocardial infa rct ion was associated with stopping smoking . All associations remained after multiple logistic regression . CONCLUSION --Smoking cessation can halve the smokers ' odds of dying after myocardial infa rct ion and psychosocial factors play a small but important role in the important decision to stop smoking . Health professionals should continue to stress the importance of stopping smoking to all patients as there is little evidence to support specific directing of advice to relatively " stress or " socially isolated " groups AIMS To analyse ( 1 ) the prognostic importance of clinical findings and lipids in patients with a previous myocardial infa rct ion and ( 2 ) the relative and absolute benefit of simvastatin in patients at low , medium and high predicted risk . METHODS The 4S was a double-blind , r and omized , clinical trial of long-term treatment with simvastatin or matching placebo in patients with myocardial infa rct ion or angina pectoris , serum total cholesterol 5.5 - 8.0 mmol x l(-1 ) , and serum triglycerides < or=2.5 mmol x l(-1 ) . The present study only deals with those 3525 patients who had a previous myocardial infa rct ion . End-points comprised coronary death , definite and probable hospital verified myocardial infa rct ion , and resuscitated cardiac arrest . Because there were few women the primary analyses were performed among men . RESULTS A Cox model analysis in the placebo group identified the following independent predictors of coronary events : a history of hypertension ( P=0.023 ) , diabetes ( P=0.0001 ) , smoking after the myocardial infa rct ion ( P=0.010 ) , total cholesterol ( P=0.020 ) , and HDL cholesterol ( P=0.062 ) . The relative reduction of risk by simvastatin treatment in patients at low , medium and high predicted risk was 38 % , 39 % and 42 % , respectively , but the corresponding absolute benefit per 100 patients treated for 6 years increased from 7.9 to 16.2 . CONCLUSION In addition to serum lipids , clinical variables contributed significantly to prediction . The relative benefit from simvastatin treatment was independent of predicted risk , but the absolute benefit increased from low to high risk BACKGROUND The long-term clinical effects of smoking and smoking cessation after  venous coronary bypass surgery  have not been well established . METHODS AND RESULTS Four hundred fifteen patients who underwent venous coronary bypass surgery between April 1976 and April 1977 were followed up prospect ively for 15 years . Multivariate Cox survival analysis revealed that patients who smoked at the time of surgery had no elevated risks for clinical events compared with nonsmokers . However , smoking behavior at 1 and 5 years after surgery appeared to be an important predictor of clinical events during the subsequent follow-up period . Compared with patients who stopped smoking since surgery , smokers at 1 year after surgery had more than twice the risk for myocardial infa rct ion and reoperation . Patients who were still smoking at 5 years after surgery had even more elevated risks for myocardial infa rct ion and reoperation and a significantly increased risk for angina pectoris compared with patients who stopped smoking since surgery and patients who never smoked . Patients who started to smoke again within 5 years after surgery had increased risks for reoperation and angina pectoris . No differences in outcome were found between patients who stopped smoking since surgery and nonsmokers . CONCLUSIONS Our results show that smoking cessation after coronary bypass surgery may have important beneficial effects on clinical events during long-term follow-up Abstract Objective To compare the hazards of cigarette smoking in men who formed their habits at different periods , and the extent of the reduction in risk when cigarette smoking is stopped at different ages . Design Prospect i ve study that has continued from 1951 to 2001 . Setting United Kingdom . Participants 34 439 male British doctors . Information about their smoking habits was obtained in 1951 , and periodically thereafter ; cause specific mortality was monitored for 50 years . Main outcome measures Overall mortality by smoking habit , considering separately men born in different periods . Results The excess mortality associated with smoking chiefly involved vascular , neoplastic , and respiratory diseases that can be caused by smoking . Men born in 1900 - 1930 who smoked only cigarettes and continued smoking died on average about 10 years younger than lifelong non-smokers . Cessation at age 60 , 50 , 40 , or 30 years gained , respectively , about 3 , 6 , 9 , or 10 years of life expectancy . The excess mortality associated with cigarette smoking was less for men born in the 19th century and was greatest for men born in the 1920s . The cigarette smoker versus non-smoker probabilities of dying in middle age ( 35 - 69 ) were 42 % ν24 % ( a twofold death rate ratio ) for those born in 1900 - 1909 , but were 43 % ν 15 % ( a threefold death rate ratio ) for those born in the 1920s . At older ages , the cigarette smoker versus non-smoker probabilities of surviving from age 70 to 90 were 10 % ν 12 % at the death rates of the 1950s ( that is , among men born around the 1870s ) but were 7 % ν 33 % ( again a threefold death rate ratio ) at the death rates of the 1990s ( that is , among men born around the 1910s ) . Conclusion A substantial progressive decrease in the mortality rates among non-smokers over the past half century ( due to prevention and improved treatment of disease ) has been wholly outweighed , among cigarette smokers , by a progressive increase in the smoker ν non-smoker death rate ratio due to earlier and more intensive use of cigarettes . Among the men born around 1920 , prolonged cigarette smoking from early adult life tripled age specific mortality rates , but cessation at age 50 halved the hazard , and cessation at age 30 avoided almost all of it The importance of three risk factors -- serum total cholesterol , systolic blood pressure , and cigarette smoking -- on the risk of new major ischaemic heart disease events in men who already have evidence of ischaemic heart disease was assessed . Data from the initial examination in a large prospect i ve study of cardiovascular disease in middle aged men ( the British Regional Heart Study ) were used to separate 7710 men into three groups on the basis of a resting electrocardiogram , a st and ardised chest pain question naire , and recall of a doctor 's diagnosis of angina or of a previous heart attack : ( group 1 ) no evidence of ischaemic heart disease ( 75 % ) , ( group 2 ) evidence of ischaemic heart disease short of a definite myocardial infa rct ion ( 20 % ) , ( group 3 ) definite myocardial infa rct ion ( 6 % ) . In the average follow up period of 7.5 years , 443 men suffered a new major event caused by ischaemic heart disease ( fatal or non-fatal myocardial infa rct ion or sudden cardiac death  ) . Age st and ardised event rates were determined for each of the three groups for varying levels of the established risk factors . Cigarette smoking is strongly associated with the event rate in group 1 but in men with existing heart disease , especially group 3 , differences in risk between the smoking categories were smaller . The strong relation between systolic blood pressure and event rate persisted in groups 1 and 2 but not in group 3 . The positive association between serum concentration of total cholesterol and the event rate was strongest in group 1 and weaker in groups 2 and 3 , though it remained highly significant . These observations , taken together with the results of previous prospect i ve studies and intervention trials , suggest that the important association between serum total cholesterol and the risk of heart attack persists in men with pre-existing ischaemic heart disease , including myocardial infa rct ion . Therefore , in these men the reduction of serum total cholesterol concentration may be at least as important as it is in men without evidence of ischaemic heart disease Data from the Diet and Reinfa rct ion Trial were examined to check the prognostic effects of plasma fibrinogen , plasma viscosity , white blood cell count , haemoglobin and mean platelet volume in 92 deaths among 1755 men who had recently recovered from acute myocardial infa rct ion . All these variables were significantly associated with all-cause mortality over the following 18 months ( haemoglobin negatively , the others positively ) . Those who gave up smoking following their infa rct had a lower mortality than those who continued to smoke ( 4.1 % and 7.9 % respectively ) , and this effect appeared to be mediated by fibrinogen levels . Smoking habit accounted for only part of the prognostic effect of fibrinogen and white blood cell count . Haematological variables have an important prognostic significance after myocardial infa rct ion . Cessation of smoking after myocardial infa rct ion is worthwhile and has a favourable effect on plasma fibrinogen Long-term follow-up was obtained on 138 patients who participated in a prospect i ve , r and omized study comparing two weeks with three weeks of hospitalization following uncomplicated acute myocardial infa rct ion . Follow-up information was available on 123 ( 89 % ) of all r and omized patients . The mean follow-up period was 35 months for those patients who died and 99 months for those who survived . No differences were found between the two groups with respect to survival , cardiac-related deaths , frequency or severity of angina pectoris , subsequent myocardial infa rct ion , incidence of congestive heart failure , number of ventricular aneurysms , or subsequent medical therapy . A significantly greater number of survivors in both groups stopped smoking and had a normal initial heart size than those who died . This long-term follow-up study further supports the conclusions of earlier short-term studies that two weeks of hospitalization is safe in patients with uncomplicated acute myocardial infa rct ion We describe the 2- and 5-year prognoses following coronary artery bypass grafting ( CABG ) in relation to smoking habits among consecutive patients being operated on in western Sweden during a 3-year 
    Output:
    
agent
REVIEW ER 'S CONCLUSIONS Quitting smoking is associated with a substantial reduction in risk of all-cause mortality among patients with CHD .
This 36 % risk reduction appears substantial compared with other secondary preventive therapies such as cholesterol lowering which have received greater attention in recent years .
The risk reduction associated with quitting smoking seems consistent regardless of differences between the studies in terms of index cardiac events , age , sex , country , and time period .
***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 PTCA is performed primarily to improve health-related quality of life ( HRQOL ) in patients with symptomatic coronary artery disease . In patients undergoing PTCA , smoking has been shown to increase risks of late myocardial infa rct ion and death . Whether smoking also affects HRQOL after PTCA is currently unknown . Methods and Results We examined the relation between smoking status and HRQOL among 1432 patients who underwent PTCA as part of 2 multicenter clinical trials . HRQOL was assessed with the use of the Medical Outcomes Study SF-36 question naire . Patients were classified as smokers ( n=301 ) , quitters ( n=141 ) , or nonsmokers ( n=990 ) on the basis of their smoking status at the time of their index procedure and during the first year of follow-up . For the overall population , HRQOL improved significantly after PTCA for all scales except general health perception , with improvements ranging from 5.5 points for mental health to 23.2 points for role-physical functioning . After adjustment for baseline characteristics and initial HRQOL , nonsmokers had gains at 6 months that were larger than those of smokers for all health domains : physical function ( 15.4 versus 10.4 points ) , role-physical ( 24.5 versus 13.9 ) , pain ( 18.4 versus 13.3 ) , general health perception ( 1.7 versus −4.5 ) , vitality ( 11.0 versus 4.7 ) , social function ( 12.8 versus 3.5 ) , role-emotional ( 13.5 versus 6.7 ) , and mental health ( 6.8 versus 0.8;P < 0.02 for all comparisons ) . Quitters had 6-month HRQOL improvements that were greater than those in smokers for all domains as well . Findings were similar at 1 year . Conclusions Quality -of-life benefits of PTCA are diminished by continued smoking . Efforts to promote smoking cessation at the time of PTCA may substantially improve the health outcomes of these procedures STUDY OBJECTIVE --To examine the effect on mortality of stopping smoking after myocardial infa rct ion and the psychosocial factors that influence the decision to stop . DESIGN -- Analysis of smokers in a large prospect i ve study . Self completed question naires provided information on psychosocial factors . SETTING --Coronary care units at six English hospitals participating in a multicentre clinical trial . SUBJECTS -- These comprised consenting myocardial infa rct ion survivors who had been identified as smokers and who completed question naires within seven days of infa rct at six hospitals participating in the Anglo-Sc and inavian study of early thrombolysis . The 532 patients identified have been followed for over five and a half years . The main outcome measure was five year all cause mortality . MAIN RESULTS --Smokers who stopped within one month showed significantly reduced mortality compared with those who persisted , adjusting for other prognostic indicators ( odds ratio 0.56 , 95 % confidence interval 0.33 , 0.98 ) . Overall , 74 % stopped smoking . Being married , low life stress levels before infa rct , and higher social class were associated with stopping smoking but the differentials were small . Of the clinical variables , a final diagnosis of definite myocardial infa rct ion was associated with stopping smoking . All associations remained after multiple logistic regression . CONCLUSION --Smoking cessation can halve the smokers ' odds of dying after myocardial infa rct ion and psychosocial factors play a small but important role in the important decision to stop smoking . Health professionals should continue to stress the importance of stopping smoking to all patients as there is little evidence to support specific directing of advice to relatively " stress or " socially isolated " groups AIMS To analyse ( 1 ) the prognostic importance of clinical findings and lipids in patients with a previous myocardial infa rct ion and ( 2 ) the relative and absolute benefit of simvastatin in patients at low , medium and high predicted risk . METHODS The 4S was a double-blind , r and omized , clinical trial of long-term treatment with simvastatin or matching placebo in patients with myocardial infa rct ion or angina pectoris , serum total cholesterol 5.5 - 8.0 mmol x l(-1 ) , and serum triglycerides < or=2.5 mmol x l(-1 ) . The present study only deals with those 3525 patients who had a previous myocardial infa rct ion . End-points comprised coronary death , definite and probable hospital verified myocardial infa rct ion , and resuscitated cardiac arrest . Because there were few women the primary analyses were performed among men . RESULTS A Cox model analysis in the placebo group identified the following independent predictors of coronary events : a history of hypertension ( P=0.023 ) , diabetes ( P=0.0001 ) , smoking after the myocardial infa rct ion ( P=0.010 ) , total cholesterol ( P=0.020 ) , and HDL cholesterol ( P=0.062 ) . The relative reduction of risk by simvastatin treatment in patients at low , medium and high predicted risk was 38 % , 39 % and 42 % , respectively , but the corresponding absolute benefit per 100 patients treated for 6 years increased from 7.9 to 16.2 . CONCLUSION In addition to serum lipids , clinical variables contributed significantly to prediction . The relative benefit from simvastatin treatment was independent of predicted risk , but the absolute benefit increased from low to high risk BACKGROUND The long-term clinical effects of smoking and smoking cessation after  venous coronary bypass surgery  have not been well established . METHODS AND RESULTS Four hundred fifteen patients who underwent venous coronary bypass surgery between April 1976 and April 1977 were followed up prospect ively for 15 years . Multivariate Cox survival analysis revealed that patients who smoked at the time of surgery had no elevated risks for clinical events compared with nonsmokers . However , smoking behavior at 1 and 5 years after surgery appeared to be an important predictor of clinical events during the subsequent follow-up period . Compared with patients who stopped smoking since surgery , smokers at 1 year after surgery had more than twice the risk for myocardial infa rct ion and reoperation . Patients who were still smoking at 5 years after surgery had even more elevated risks for myocardial infa rct ion and reoperation and a significantly increased risk for angina pectoris compared with patients who stopped smoking since surgery and patients who never smoked . Patients who started to smoke again within 5 years after surgery had increased risks for reoperation and angina pectoris . No differences in outcome were found between patients who stopped smoking since surgery and nonsmokers . CONCLUSIONS Our results show that smoking cessation after coronary bypass surgery may have important beneficial effects on clinical events during long-term follow-up Abstract Objective To compare the hazards of cigarette smoking in men who formed their habits at different periods , and the extent of the reduction in risk when cigarette smoking is stopped at different ages . Design Prospect i ve study that has continued from 1951 to 2001 . Setting United Kingdom . Participants 34 439 male British doctors . Information about their smoking habits was obtained in 1951 , and periodically thereafter ; cause specific mortality was monitored for 50 years . Main outcome measures Overall mortality by smoking habit , considering separately men born in different periods . Results The excess mortality associated with smoking chiefly involved vascular , neoplastic , and respiratory diseases that can be caused by smoking . Men born in 1900 - 1930 who smoked only cigarettes and continued smoking died on average about 10 years younger than lifelong non-smokers . Cessation at age 60 , 50 , 40 , or 30 years gained , respectively , about 3 , 6 , 9 , or 10 years of life expectancy . The excess mortality associated with cigarette smoking was less for men born in the 19th century and was greatest for men born in the 1920s . The cigarette smoker versus non-smoker probabilities of dying in middle age ( 35 - 69 ) were 42 % ν24 % ( a twofold death rate ratio ) for those born in 1900 - 1909 , but were 43 % ν 15 % ( a threefold death rate ratio ) for those born in the 1920s . At older ages , the cigarette smoker versus non-smoker probabilities of surviving from age 70 to 90 were 10 % ν 12 % at the death rates of the 1950s ( that is , among men born around the 1870s ) but were 7 % ν 33 % ( again a threefold death rate ratio ) at the death rates of the 1990s ( that is , among men born around the 1910s ) . Conclusion A substantial progressive decrease in the mortality rates among non-smokers over the past half century ( due to prevention and improved treatment of disease ) has been wholly outweighed , among cigarette smokers , by a progressive increase in the smoker ν non-smoker death rate ratio due to earlier and more intensive use of cigarettes . Among the men born around 1920 , prolonged cigarette smoking from early adult life tripled age specific mortality rates , but cessation at age 50 halved the hazard , and cessation at age 30 avoided almost all of it The importance of three risk factors -- serum total cholesterol , systolic blood pressure , and cigarette smoking -- on the risk of new major ischaemic heart disease events in men who already have evidence of ischaemic heart disease was assessed . Data from the initial examination in a large prospect i ve study of cardiovascular disease in middle aged men ( the British Regional Heart Study ) were used to separate 7710 men into three groups on the basis of a resting electrocardiogram , a st and ardised chest pain question naire , and recall of a doctor 's diagnosis of angina or of a previous heart attack : ( group 1 ) no evidence of ischaemic heart disease ( 75 % ) , ( group 2 ) evidence of ischaemic heart disease short of a definite myocardial infa rct ion ( 20 % ) , ( group 3 ) definite myocardial infa rct ion ( 6 % ) . In the average follow up period of 7.5 years , 443 men suffered a new major event caused by ischaemic heart disease ( fatal or non-fatal myocardial infa rct ion or sudden cardiac death  ) . Age st and ardised event rates were determined for each of the three groups for varying levels of the established risk factors . Cigarette smoking is strongly associated with the event rate in group 1 but in men with existing heart disease , especially group 3 , differences in risk between the smoking categories were smaller . The strong relation between systolic blood pressure and event rate persisted in groups 1 and 2 but not in group 3 . The positive association between serum concentration of total cholesterol and the event rate was strongest in group 1 and weaker in groups 2 and 3 , though it remained highly significant . These observations , taken together with the results of previous prospect i ve studies and intervention trials , suggest that the important association between serum total cholesterol and the risk of heart attack persists in men with pre-existing ischaemic heart disease , including myocardial infa rct ion . Therefore , in these men the reduction of serum total cholesterol concentration may be at least as important as it is in men without evidence of ischaemic heart disease Data from the Diet and Reinfa rct ion Trial were examined to check the prognostic effects of plasma fibrinogen , plasma viscosity , white blood cell count , haemoglobin and mean platelet volume in 92 deaths among 1755 men who had recently recovered from acute myocardial infa rct ion . All these variables were significantly associated with all-cause mortality over the following 18 months ( haemoglobin negatively , the others positively ) . Those who gave up smoking following their infa rct had a lower mortality than those who continued to smoke ( 4.1 % and 7.9 % respectively ) , and this effect appeared to be mediated by fibrinogen levels . Smoking habit accounted for only part of the prognostic effect of fibrinogen and white blood cell count . Haematological variables have an important prognostic significance after myocardial infa rct ion . Cessation of smoking after myocardial infa rct ion is worthwhile and has a favourable effect on plasma fibrinogen Long-term follow-up was obtained on 138 patients who participated in a prospect i ve , r and omized study comparing two weeks with three weeks of hospitalization following uncomplicated acute myocardial infa rct ion . Follow-up information was available on 123 ( 89 % ) of all r and omized patients . The mean follow-up period was 35 months for those patients who died and 99 months for those who survived . No differences were found between the two groups with respect to survival , cardiac-related deaths , frequency or severity of angina pectoris , subsequent myocardial infa rct ion , incidence of congestive heart failure , number of ventricular aneurysms , or subsequent medical therapy . A significantly greater number of survivors in both groups stopped smoking and had a normal initial heart size than those who died . This long-term follow-up study further supports the conclusions of earlier short-term studies that two weeks of hospitalization is safe in patients with uncomplicated acute myocardial infa rct ion We describe the 2- and 5-year prognoses following coronary artery bypass grafting ( CABG ) in relation to smoking habits among consecutive patients being operated on in western Sweden during a 3-year 
    Output:
    