***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: Objective : The rising incidence and the strong male predominance among patients with esophageal and gastric cardia adenocarcinoma remain unexplained . We hypothesized that occupational airborne exposures in a traditional male dominated industry might contribute to these observations . Methods : A prospect i ve , large cohort study of Swedish construction workers was linked to the Swedish population -based registers of Cancer , Causes of Death and Total Population . 260,052 men were followed from 1971 through 2000 .  Industrial hygienists assessed specific exposures for 200 job titles , and occupational airborne exposures were analyzed separately and combined .  Incidence rate ratios ( IRR ) , with 95 % confidence intervals ( CI ) , were estimated in multivariable Cox regression models adjusted for attained age , calendar period , smoking status and body mass . Results : We found positive associations between high exposure to asbestos ( IRR 4.5 [ 95 % CI 1.4–14.3 ] ) and cement dust ( IRR 3.8 [ 95 % CI 1.5–9.6 ] ) and risk of esophageal adenocarcinoma . Associations were seen between high exposure to asphalt fumes ( IRR 2.3 [ 95 % CI 1.0–5.3 ] ) and wood dust ( IRR 4.8 [ 95 % CI 1.2–19.4 ] ) and risk of cardia adenocarcinoma . No consistent associations regarding esophageal squamous-cell carcinoma were found . Conclusions : Exposure to asbestos and cement dust may be risk factors for esophageal adenocarcinoma , and exposure to asphalt fumes and wood dust may increase the risk of cardia adenocarcinoma . However , these associations can not explain the major sex differences or the increasing incidence trends of these tumors Objectives : To prospect ively assess the influence of body mass index ( BMI ) , tobacco , and alcohol on the occurrence of esophageal , gastric cardia , and non-cardia gastric adenocarcinoma , and to detect any sex differences that could explain the male predominance of these tumors . Methods : A case-control study nested in the General Practitioner Research Data base in the United Kingdom , 1994–2001 . Odds ratios ( ORs ) were calculated with 95 % confidence intervals ( CI ) , including multivariate analysis . Results : During follow-up of 4,340,207 person-years , we identified 287 esophageal adenocarcinomas , 195 gastric cardia adenocarcinomas , 327 gastric non-cardia adenocarcinomas , and 10,000 controls . A positive association was found between overweight ( BMI > 25 kg/m2 ) and esophageal adenocarcinoma ( OR 1.67 , 95 % CI 1.22–2.30 ) , and gastric cardia adenocarcinoma ( OR 1.46 , 95 % CI 0.98–2.18 ) , but not non-cardia gastric adenocarcinoma . The association between BMI and esophageal and gastric cardia adenocarcinoma were dose-dependent and seemingly independent of reflux . No strong sex differences were identified . Smokers , particularly females , were at increased risk of all studied adenocarcinomas , while no association with alcohol was found . Conclusions : Overweight increases risk of esophageal and gastric cardia adenocarcinoma , while tobacco smoking increases risk of esophageal , gastric cardia , and non-cardia gastric adenocarcinoma . The male predominance is not explained by sex differences in risk factor profiles of the studied exposures There is a relation between excess body mass index and overall cancer incidence and mortality , but the relation to noncardia gastric cancer is inconsistent . A high physical activity level decreases the risk of several cancers , but few studies have focused on gastric cancer . We conducted a population -based , prospect i ve cohort study in Nord-Trondelag county in Norway . During 1984 to 1986 , all adult residents were invited to participate in a health survey  , where body height and weight were measured , and frequency , duration , and intensity of recreational physical activity , together with potential confounding factors , were assessed by question naires . New gastric cancers occurring during follow-up in 1984 to 2002 were identified by linkage to the Cancer Registry of Norway . Cox proportional hazards regression models were used to calculate hazard ratios with 95 % confidence intervals , adjusted for age , sex , occupation , salt intake , smoking , and alcohol drinking . Follow-up of 73,133 cohort members ( 88 % of all inhabitants ) revealed 313 gastric cancers , including 264 noncardia cancers . No statistically significant associations were revealed between different levels of body mass index and risk of noncardia gastric cancer . A statistically significant 50 % risk reduction among persons reporting at least a moderate level of recreational physical activity , based on a summary score of physical activity ( hazard ratio , 0.5 ; 95 % confidence interval , 0.3 - 0.9 ) , and a dose-response relation was indicated ( P for trend = 0.01 ) . It is concluded that recreational physical activity might have a protective effect against gastric cancer . The sedentary lifestyle gaining ground in western societies might counteract the ongoing decrease in incidence of gastric cancer . ( Cancer Epidemiol Biomarkers Prev 2008;17(1):135–40 Esophageal cancer incidence and mortality rates in Linxian , China are among the highest in the world . We examined risk factors for esophageal squamous cell carcinoma ( ESCC ) , gastric cardia cancer ( GCC ) , and gastric noncardia cancer ( GNCC ) in a population -based , prospect i ve study of 29,584 adults who participated in the Linxian General Population Trial . All study participants completed a baseline question naire that included questions on demographic characteristics , personal and family history of disease , and lifestyle factors . After 15 years of follow-up , a total of 3,410 incident upper gastrointestinal cancers were identified , including 1,958 ESCC , 1,089 GCC and 363 GNCC . Cox proportional hazard models were used to estimate risks . Increased age and a positive family history of esophageal cancer ( including ESCC or GCC ) were significantly associated with risk at all 3 cancer sites . Additional risk factors for ESCC included being born in Linxian , increased height , cigarette smoking and pipe smoking ; for GCC , male gender , consumption of moldy breads and pipe smoking ; and for GNCC , male gender and cigarette smoking . Protective factors for ESCC included formal education , water piped into the home , increased consumption of meat , eggs and fresh fruits and increased BMI ; for GCC , formal education , water piped into the home , increased consumption of eggs and fresh fruits and alcohol consumption ; and for GNCC , increased weight and BMI . General socioeconomic status ( SES ) is a common denominator in many of these factors and improving SES is a promising approach for reducing the tremendous burden of upper gastrointestinal cancers in Linxian Recent evidence links obesity with the rising incidence of oesophageal adenocarcinoma . In Irel and between 1995 and 2004 the incidence of oesophageal adenocarcinoma increased by 38 % , and this coincided with a 67 % increase in the prevalence of obesity . In this study , a prospect i ve case-control study was undertaken in 760 patients presenting to a tertiary centre between 1994 and 2004 diagnosed with cancer of the oesophagus , gastric cardia or stomach . Data were compared with 893 healthy controls .  Multivariate logistic regression models were used to calculate the odds ratio ( OR ) of developing either cancer type according to quartiles of body mass index ( BMI ) . Based on pre-illness BMI , 82 % of patients who developed  adenocarcinoma of the oesophagus  were either overweight or obese compared with 59 % of the healthy control population ( P<0.001 ) . A dose-dependent relationship existed between BMI and oesophageal adenocarcinoma in males . The adjusted odds ratio was 4.3 ( 95 % CI : 2.3 - 7.9 ) among males in the highest BMI quartile compared with males in the lowest quartile ( P<0.001 for trend ) . Using common cut-off points for BMI , the OR of adenocarcinoma of the lower oesophagus was 11.3 times higher ( 95 % CI : 3.5 - 36.4 ) for individuals with a BMI > 30 kg/m2 versus individuals with a BMI < 22 kg/m2 ( P<0.001 for trend ) . For adenocarcinoma of the gastric cardia , males in the top quartile of BMI had an OR of 3.5 ( 95 % CI : 1.3 - 9.4 ) compared with the lowest quartile ( P=0.03 for trend ) . A significant ( P<0.001 ) inverse relationship between BMI and oesophageal SCC was observed . The odds ratio for adenocarcinoma of the oesophagus , the oesophago-gastric junction and gastric cardia rose significantly with increasing BMI . For tumours of the lower oesophagus , obesity increased the risk 10.9-fold . The increased risk is significant in males only CONTEXT Endogenous hormones are a primary cause of breast cancer . Adiposity affects circulating hormones , particularly in postmenopausal women , and may be a modifiable risk factor for breast cancer . OBJECTIVE To assess the associations of  adult weight change since age 18 years and since menopause with the risk of breast cancer among postmenopausal women . DESIGN , SETTING , AND PARTICIPANTS Prospect i ve cohort study within the Nurses ' Health Study . A total of 87,143 postmenopausal women , aged 30 to 55 years and free of cancer , were followed up for up to 26 years ( 1976 - 2002 ) to assess  weight change since age 18 years . Weight change since menopause  was assessed among 49,514 women who were followed up for up to 24 years . MAIN OUTCOME MEASURE Incidence of invasive breast cancer . RESULTS Overall , 4393 cases of invasive breast cancer were documented . Compared with those who maintained weight , women who gained 25.0 kg or more since age 18 years were at an increased risk of breast cancer ( relative risk [ RR ] , 1.45 ; 95 % confidence interval [ CI ] , 1.27 - 1.66 ; P<.001 for trend ) , with a stronger association among women who have never taken postmenopausal hormones ( RR,1.98 ; 95 % CI , 1.55 - 2.53 ) . Compared with weight maintenance , women who gained 10.0 kg or more since menopause were at an increased risk of breast cancer ( RR , 1.18 ; 95 % CI , 1.03 - 1.35 ; P = .002 for trend ) . Women who had never used postmenopausal hormones , lost 10.0 kg or more since menopause , and kept the weight off were at a lower risk than those who maintained weight ( RR , 0.43 ; 95 % CI , 0.21 - 0.86 ; P = .01 for weight loss trend ) . Overall , 15.0 % ( 95 % CI , 12.8%-17.4 % ) of breast cancer cases in this population may be attributable to weight gain of 2.0 kg or more since age 18 years and 4.4 % ( 95 % CI , 3.6%-5.5 % ) attributable to weight gain of 2.0 kg or more since menopause . Among those who did not use postmenopausal hormones , the population attributable risks are 24.2 % ( 95 % CI , 19.8%-29.1 % ) for a weight gain since age 18 years and 7.6 % ( 95 % CI , 5.9%-9.7 % ) for  weight gain  since menopause . CONCLUSIONS These data suggest that weight gain during adult life , specifically since menopause , increases the risk of breast cancer among postmenopausal women , whereas weight loss after menopause is associated with a decreased risk of breast cancer . Thus , in addition to other known benefits of healthy weight , our results provide another reason for women approaching menopause to maintain or lose weight , as appropriate Objective To examine the relation between body mass index ( kg/m2 ) and  cancer incidence and mortality . Design Prospect i ve cohort study . Participants 1.2 million UK women recruited into the Million Women Study , aged 50 - 64 during 1996 - 2001 , and followed up , on average , for 5.4 years for cancer incidence and 7.0 years for cancer mortality . Main outcome measures Relative risks of incidence and mortality for all cancers , and for 17 specific types of cancer , according to body mass index , adjusted for age , geographical region , socioeconomic status , age at first birth , parity , smoking status , alcohol intake , physical activity , years since menopause , and use of hormone replacement therapy . Results 45 037 incident cancers and 17 203 deaths from cancer occurred over the follow-up period . Increasing body mass index was associated with an increased incidence of endometrial cancer ( trend in relative risk per  
    Output:
    
The combined results of this meta- analysis , however , do indicate that overweight and obesity are associated with an increased risk of gastric cancer .
The strength of the association also increases with increasing BMI