***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 Obstructive airways disease in older patients is reported to be not only common , but frequently overlooked and untreated by general practitioners . This study examines the value of screening elderly patients in a large semi-rural general practice for potentially treatable asthma and chronic obstructive pulmonary disease ( COPD ) . METHODS A r and om sample of 353 patients aged 60–75 years attended a nurse run screening clinic for pulmonary function testing , serial peak flow recording , and completion of a symptom question naire .  Patients with a low forced expiratory volume in one second ( below the fifth centile of their predicted value ) or > 15 % mean diurnal variation in peak flow were referred to a doctor ’s clinic for further diagnostic assessment and /or to discuss possible treatment where appropriate . RESULTS Fifty eight patients ( 16.4 % ) had obstructive airways disease , the prevalence of asthma being 6.5 % and that of COPD 9.9 % . Of these , 30 had no previous diagnosis of airways disease and were not on treatment ; eight of them had significant airways reversibility and 10 were current smokers . No newly diagnosed patients had severe disease as measured by pulmonary function or quality of life assessment , and six patients accepted treatment . CONCLUSION Few older patients benefited from a screening programme for obstructive airways disease in a semi-rural general practice OBJECTIVE The aim of this study was to compare the prevalence of adult respiratory symptoms and conditions in a rural setting with a metropolitan setting . METHODOLOGY We used cross-sectional population surveys of respiratory health using the European Respiratory Health Survey screening question naire . A r and om sample of 4455 eligible young adults aged 20 - 44 years , from electoral rolls in south-eastern metropolitan Melbourne , Victoria , and 4521 from rural south-western New South Wales were surveyed . RESULTS Response rates of 72 % ( n=3194 ) and 69 % ( n=3121 ) were achieved in Melbourne and the Riverina , respectively . Respondents from the Riverina reported significantly higher prevalences of nocturnal dyspnoea ( P<0.01 ) , chronic bronchitis ( P=0.03 ) , an asthma attack in the previous 12 months ( P<0.001 ) , ever having had asthma ( P<0.001 ) and doctor-diagnosed asthma ( P<0.001 ) compared to those from Melbourne . However , among those with ' asthma attacks in the last 12 months ' , Melbourne respondents experienced a higher frequency of attacks ( P<0.05 ) . Riverina respondents reported a higher prevalence of smoking ( P<0.05 ) and smoked more cigarettes on average ( P<0.001 ) than Melbourne respondents . However , annoyance from air pollution was higher in Melbourne than in the Riverina . CONCLUSIONS These results suggest that asthma is more prevalent in rural southern New South Wales than in Melbourne but follows a different pattern of exacerbations STUDY OBJECTIVE It is still unclear if men and women are equally susceptible to the hazards of tobacco smoking . The objective of this study was to examine  smoking related mortality among men and women . DESIGN In 1963 a question naire concerning tobacco smoking habits was sent out to a r and om sample from the 1960 Swedish census population . Date and cause of death have been collected for the deceased in the cohort through 1996 . SETTING Sweden . PARTICIPANTS The survey included a total of 27 841 men and 28 089 women , aged 18–69 years . The response rate was 93.1 % among the men and 95.4 % among the women . MAIN RESULTS After adjustment for age and place of residence positive associations were found between cigarette smoking and mortality from ischaemic heart disease , aortic aneurysm , bronchitis and emphysema , cancer of the lung , upper aerodigestive sites , bladder , pancreas in both men and women , but not from cerebrovascular disease . When the effect of amount of the cigarette consumption was considered , female smokers displayed , for example , slightly higher relative death rates from ischaemic heart disease . However , no statistically significant gender differential in relative mortality rates was observed for any of the studied diseases . CONCLUSIONS Women and men in this Swedish cohort seem equally susceptible to the hazards of smoking , when the gender differential in smoking characteristics is accounted for . Although the cohort under study is large , there were few female smokers in the high consuming categories and the relative risk estimates are therefore accompanied by wide confidence intervals in these categories Background Exposure to environmental tobacco smoke ( ETS ) , which contains potent respiratory irritants , may lead to chronic airway inflammation and obstruction . Although ETS exposure appears to cause asthma in children and adults , its role in causing COPD has received limited attention in epidemiologic studies . Methods Using data from a population -based sample of 2,113 U.S. adults aged 55 to 75 years , we examined the association between lifetime ETS exposure and the risk of developing COPD .  Participants were recruited from all 48 contiguous U.S. states by r and om digit dialing . Lifetime ETS exposure was ascertained by structured telephone interview . We used a st and ard epidemiologic approach to define COPD based on a self-reported physician diagnosis of chronic bronchitis , emphysema , or COPD . Results Higher cumulative lifetime home and work exposure were associated with a greater risk of COPD . The highest quartile of lifetime home ETS exposure was associated with a greater risk of COPD , controlling for age , sex , race , personal smoking history , educational attainment , marital status , and occupational exposure to vapors , gas , dusts , or fumes during the longest held job ( OR 1.55 ; 95 % CI 1.09 to 2.21 ) . The highest quartile of lifetime workplace ETS exposure was also related to a greater risk of COPD ( OR 1.36 ; 95 % CI 1.002 to 1.84 ) . The population attributable fraction was 11 % for the highest quartile of home ETS exposure and 7 % for work exposure . Conclusion ETS exposure may be an important cause of COPD . Consequently , public policies aim ed at preventing public smoking may reduce the burden of COPD -related death and disability , both by reducing direct smoking and ETS exposure Using the M.R.C. Question naire on Bronchitis and a question naire on smoking on a r and om sample of persons aged 62 and upwards , information was gathered about respiratorysymptoms and smoking habits . BACKGROUND Although many studies have examined the adverse health effects of pipe smoking combined with other forms of tobacco use , few have included large numbers of exclusive pipe smokers . The prevalence of pipe smoking has declined since the 1960s , yet usage is still common regionally , especially among older population s. METHODS Using Cox proportional hazards models , we examined the association between pipe smoking and mortality from  tobacco-related cancers and other diseases  in a cohort of U.S. men enrolled in the Cancer Prevention Study II , an American Cancer Society prospect i ve study . The cohort of 138 307 men included those who reported , in their 1982 enrollment question naire , exclusive current or former use of pipes ( n = 15,263 men ) or never use of any tobacco product ( n = 123,044 men ) . Analyses were based on 23 589 men who died during 18 years of follow-up . RESULTS Current pipe smoking , compared with never use of tobacco , was associated with an increased risk of death from cancers of the lung ( relative risk [ RR ] = 5.00 , 95 % confidence interval [ CI ] = 4.16 to 6.01 ) , oropharynx ( RR = 3.90 , 95 % CI = 2.15 to 7.08 ) , esophagus ( RR = 2.44 , 95 % CI = 1.51 to 3.95 ) , colorectum ( RR = 1.41 , 95 % CI = 1.15 to 1.73 ) , pancreas ( RR = 1.61 , 95 % CI = 1.24 to 2.09 ) , and larynx ( RR = 13.1 , 95 % CI = 5.2 to 33.1 ) , and from coronary heart disease ( RR = 1.30 , 95 % CI = 1.18 to 1.43 ) , cerebrovascular disease ( RR = 1.27 , 95 % CI = 1.09 to 1.48 ) , and chronic obstructive pulmonary disease ( RR = 2.98 , 95 % CI = 2.17 to 4.11 ) . These risks were generally smaller than those associated with cigarette smoking and similar to or larger than those associated with cigar smoking . Relative risks of lung cancer showed statistically significant increases with number of pipes smoked per day , years of smoking , and depth of inhalation and decreases with years since quitting . CONCLUSION Results from this large prospect i ve study suggest that pipe smoking confers a risk of tobacco-associated disease similar to cigar smoking OBJECTIVE To evaluate prospect ively the health risk of cigarette smoking in middle-aged men in Shanghai , China . DESIGN Prospect i ve cohort study with annual follow-up . PARTICIPANTS A total of 18 244 male residents of Shanghai , China , enrolled in the study during January 1 , 1986 , through September 30 , 1989 , and actively followed via annual visits . RESULTS By September 30 , 1993 , 852 deaths and 554 incident cancer cases were identified during the follow-up period , which averaged 5.4 years per subject . The overall incidence rate for cancer was 568 per 100 000 man-years , with the 3 leading sites being lung ( 146/100 000 ) , stomach ( 116/100 000 ) , and liver ( 81/100 000 ) . Forty-one percent of all deaths were from cancer . Stroke was the most frequent cause of death unrelated to cancer , with an age-adjusted rate 4.2 times higher than that of US white men ( 201/100 000 vs 48/100 000 ) , followed by ischemic heart disease , with an age-adjusted rate one-fifth that of US white men ( 69/100 000 vs 366/100 000 ) . Compared with lifelong nonsmokers , the relative risks in heavy smokers ( 20 or more cigarettes per day ) after adjustment for alcohol consumption were 2.2 for any incident cancer , 9.4 for incident lung cancer , 6.7 for head and neck cancer , and 1.8 for liver cancer . In terms of mortality , heavy smokers were at a 60 % greater risk of death relative to lifelong nonsmokers ; there was a 2.3-fold excess risk of death from cancer and 2-fold to 3-fold excess risk of death from heart disease . CONCLUSIONS Cigarette smoking is an important predictor of risk of cancer and mortality in men in Shanghai . Among the study subjects , 36 % of all cases of cancer and 21 % of all deaths could be attributed to cigarette smoking The present work aims to assess the international variation in the prevalence of chronic bronchitis and its main risk factor , smoking habits , in young adults of 35 centres from 16 countries .  Respiratory symptoms and pulmonary function were assessed in 17,966 subjects ( 20 - 44 yrs ) , r and omly selected from the general population , in the frame of the European Community Respiratory Health Survey . The median prevalence of chronic bronchitis was 2.6 % , with wide variations across countries ( p<0.001 ; 0.7 - 9.7 % ) . The prevalence of current smokers ranged 20.1 - 56.9 % , ( p<0.001 ) with a median value of 40 % . Current smoking was the major risk factor for chronic bronchitis , especially in males . Its effect increased according to number of pack-yrs : in males , the odds ratio of chronic bronchitis was 3.51 ( 95 % confidence interval ( CI ) 2.31 - 5.32 ) in 1 - 14 pack-yrs smokers and increased to 17.32 ( 9.97 - 30.11 ) in > or = 45 pack-yrs smokers with respect to nonsmokers . Only 30 % of the geographical variability in prevalence could be explained by differences in smoking habits , suggesting that other environmental and /or genetic factors may play an important role . In conclusion , chronic bronchitis is a substantial health problem even in young adults . The impressive prevalence in current smokers in most countries highlights the need to improve the quality of prevention Background : Both chronic obstructive pulmonary disease ( COPD ) and obstructive sleep apnea syndrome ( OSAS ) are common diseases . Some recent studies suggest an increased prevalence of COPD among subjects with OSAS . Objectives : The study objective was to evaluate whether there is an epidemiological relationship between COPD and OSAS in a r and om population sample . Material s and Methods : The study population , 356 males ( 53 % ) and 320 females , mean age 56.6  
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For COPD , RRs are higher for males , for studies conducted in North America , for cigarette smoking rather than any product smoking , and where the unexposed base is never smoking any product , and are markedly lower when asthma is included in the COPD definition .
Variations by sex , continent , smoking product and unexposed group are in the same direction for CB , but less clearly demonstrated .
For all outcomes RRs are higher when based on mortality , and for COPD are markedly lower when based on lung function .
For all outcomes , risk increases with amount smoked and pack-years .
Limited data show risk decreases with increasing starting age for COPD and CB and with increasing quitting duration for COPD .
No clear relationship is seen with duration of smoking .
Conclusions The results confirm and quantify the causal relationships with smoking