***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 
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    ***EXAMPLES*** 
    Input: BACKGROUND The " obesity paradox " is defined as an inverse association of good health , survival and obesity . Usually in healthy persons the more obese you are the more metabolic complications you have ; however , thin patients with chronic obstructive pulmonary disease ( COPD ) have more cardiovascular complications and a higher mortality rate . OBJECTIVES To explore whether atherosclerosis and peripheral artery disease ( PAD ) contribute to the higher morbidity and mortality of patients with COPD . METHODS This prospect i ve study included 87 patients with chronic COPD who were treated in the pulmonary outpatient clinic ; all signed a consent form before enrollment . We documented their  lung function ( FEV1 % ) , body mass index ( BMI ) and ankle brachial index ( ABI ) . The primary endpoints were to find an association between atherosclerosis and BMI in patients with COPD , and between atherosclerosis and severity of lung disease . RESULTS Average ABI was 1.01 + /- 0.20 , BMI was 29.33 + /- 7.48 kg/m2 , and the abdominal circumference was 107.34 + /- 18.87 cm . A positive correlation was found between BMI and ABI ( P=0.001 ) and between abdominal circumference and ABI ( P=0.000 ) . Patients with peripheral artery disease were older ( 73.6 + /- 11.5 vs. 68.1 + /- 11.6 years old , P= 0.04 ) , were thinner ( average BMI 25.5 + /- 6.2 vs. 31.06 + /- 7.3 , P= 0.001 ) , and had a lower abdominal circumference ( 97.7 + /- 18.3 vs. 111.7 + /- 17.5 cm , P=0.001 ) . No such difference was observed for years of smoking . Male PAD patients with COPD had a lower BMI ( 25.2 + /- 5.6 vs. 29.9 + /- 7.4 , P = 0.016 ) , and their abdominal circumference was smaller ( 96.1 + /- 18.0 vs. 110.2 + /- 16.5 cm , P=0.004 ) . Female PAD patients with COPD had a lower BMI ( 26.3 + /- 8.2 vs. 33.1 + /- 7.0 , P=0.045 ) , but their abdominal circumference was not different from females without PAD ( 102.0 + /- 19.7 vs. 114.0 + /- 19.4 cm , P=0.162 ) . Patients with PAD had a worse lung disease ( FEV1 % 34 + /- 8 % vs. 45 + /- 16 % , P=0.01 ) . During the 1 year of follow-up five patients died : two PAD patients due to acute myocardial infa rct ion and three non-PAD patients died from pulmonary insufficiency ( two patients ) and pulmonary emboli ( one patient ) . DISCUSSION We found that COPD patients with PAD were older and thinner and had a lower abdominal circumference and a more progressive lung disease . Extensive atherosclerosis in patients with COPD may partly explain the " obesity paradox " observed in patients with COPD Background The association between change in weight or body mass index , and mortality is widely reported , however , both measures fail to account for fat distribution . Change in waist circumference , a measure of central adiposity , in relation to mortality has not been studied extensively . Methods We investigated the association between mortality and changes in directly measured waist circumference , hips circumference and weight from baseline ( 1990–1994 ) to wave 2 ( 2003–2007 ) in a prospect i ve cohort study of people aged 40–69 years at baseline .  Cox regression , with age as the time metric and follow-up starting at wave 2 , adjusted for confounding variables , was used to estimate hazard ratios ( HRs ) and 95 % confidence intervals ( CIs ) for change in body size in relation to mortality from all causes , cardiovascular disease and cancer . Results There were 1465 deaths ( 109 cancer , 242 cardiovascular disease ) identified during an average 7.7 years of follow-up from 21 298 participants . Compared to minimal increase in body size , loss of waist circumference ( HR : 1.26 ; 95 % CI : 1.09–1.47 ) , weight ( 1.80 ; 1.54–2.11 ) , or hips circumference ( 1.35 ; 1.15–1.57 ) were associated with an increased risk of all-cause mortality , particularly for older adults .  Weight loss was associated with cardiovascular disease mortality ( 2.40 ; 1.57–3.65 ) but change in body size was not associated with obesity-related cancer mortality . Conclusion This study confirms the association between weight loss and increased mortality from all-causes for older adults . Based on evidence from observational cohort studies , weight stability may be the recommended option for most adults , especially older adults Conflicting results have been reported concerning the association between body weight and longevity . The shape of the curve relating weight to all-cause mortality has been variously described as linear , J-shaped , and even U-shaped . To assess the validity of the evidence for optimal weight recommendations , we examined the 25 major prospect i ve studies on the subject . Each study had at least one of three major biases : failure to control for cigarette smoking , inappropriate control of biologic effects of obesity , such as hypertension and hyperglycemia , and failure to control for weight loss due to sub clinical disease . The presence of these biases leads to a systematic underestimate of the impact of obesity on premature mortality . Although these biases preclude a valid assessment of optimal weight from existing data , available evidence suggests that minimum mortality occurs at relative weights at least 10 % below the US average BACKGROUND AND OBJECTIVES A high body mass index ( BMI ) is associated with lower mortality in patients undergoing hemodialysis . Short-term weight gains and losses are also related to lower and higher mortality risk , respectively . The implication s of weight gain or loss may , however , differ between obese individuals and their nonobese counterparts . DESIGN , SETTING , PARTICIPANTS , & MEASUREMENTS The Current Management of Secondary Hyperparathyroidism : A Multicenter Observational Study ( COSMOS ) is an observational study including 6797 European hemodialysis patients recruited between February 2005 and July 2007 , with prospect i ve data collection every 6 months for 3 years . Time-dependent Cox proportional hazard regressions assessed the effect of BMI and weight changes on mortality . Analyses were performed after patient stratification according to their starting BMI . RESULTS Among 6296 patients with complete data , 1643 died . At study entry , 42 % of patients had a normal weight ( BMI , 20 - 25 kg/m(2 ) ) , 11 % were underweight , 31 % were overweight , and 16 % were obese ( BMI ≥ 30 kg/m(2 ) ) . Weight loss or gain ( < 1 % or > 1 % of body weight ) was strongly associated with higher rates of mortality or survival , respectively . After stratification by BMI categories , this was true in nonobese categories and especially in underweight patients . In obese patients , however , the association between weight loss and mortality was attenuated ( hazard ratio , 1.28 [ 95 % confidence interval ( CI ) , 0.74 to 2.14 ] ) , and no survival benefit of gaining weight was seen ( hazard ratio , 0.98 [ 95 % CI , 0.59 to 1.62 ] ) . CONCLUSIONS Assuming that these weight changes were unintentional , our study brings attention to rapid weight variations as a clinical sign of health monitoring in hemodialysis patients . In addition , a patient 's BMI modifies the strength of the association between weight changes with mortality BACKGROUND Although weight loss reduces risk for comorbid diseases , many observational studies suggest that weight loss is associated with increased mortality risk , leading to reluctance by clinicians to consider weight reduction as a strategy to maintain health and independence in older adults . However , whether the observed weight loss is intentional is difficult to determine and may not accurately represent the mortality risk associated with intentional weight reduction . Data from the Arthritis , Diet , and Activity Promotion Trial ( ADAPT ) were used to determine whether r and omization to a weight reduction program was associated with total mortality in overweight/obese older adults . METHODS  ADAPT ( n = 318 ; mean age 69 + /- 6 years , body mass index 34 + /- 5 kg/m2 , 72 % female ) assessed the influence of weight loss ( achieved through dietary counseling and lifestyle modification ) and /or exercise on function in overweight/obese older adults with knee osteoarthritis . ADAPT ended in December 1999 . Participant vital was ascertained status through December 2006 using the National Death and Social Security Indexes . RESULTS The mortality rate for those r and omized to the 18-month weight loss intervention ( n = 159 , mean weight loss = -4.8 kg , 15 deaths ) was lower than that for those not r and omized to the weight loss intervention ( n = 159 , mean weight loss = -1.4 kg , 30 deaths ; hazard rate ratio = 0.5 , 95 % confidence interval 0.3 - 1.0 ) . Results were not appreciably changed when analyses were stratified by age , gender , baseline weight status , or magnitude of weight loss . CONCLUSIONS In older adults , intentional weight loss was not associated with increased total mortality and may reduce mortality risk . Observational studies of weight loss , especially when intentionality can not be rigorously established , may be misleading with respect to the effect of weight loss on mortality Although 25 % of US men indicate that they are trying to lose weight , the association between intentional weight loss  and longevity in men is unknown . The authors analyzed prospect i ve data from 49,337 overweight ( initial body mass index > or = 27 ) white men aged 40 - 64 years who , in 1959 - 1960 , answered questions on weight change direction , amount , time interval , and intent . Vital status was determined in 1972 . Proportional hazards regression estimated mortality rate ratios for men who intentionally lost weight compared with men with no weight change . Analyses were stratified by health status and adjusted for age , initial body mass index , smoking status , alcohol intake , education , physical activity , health history , and physical symptoms . Among men with no reported health conditions ( n = 36,280 ) , intentional weight loss was not associated with total , cardiovascular ( CVD ) , or cancer mortality , but diabetes-associated mortality was increased 48 % ( 95 % confidence interval ( CI ) -7 % to + 133 % ) among those who lost 20 pounds ( 9.1 kg ) or more ; this increase was largely related to non-CVD mortality . Among men with reported health conditions ( n = 13,057 ) , intentional weight loss had no association with total or CVD mortality , but cancer mortality increased 25 % ( 95 % confidence interval -4 % to + 63 % ) among those who lost 20 pounds or more . Diabetes-associated mortality was reduced 32 % ( 95 % confidence interval -52 % to -5 % ) among those who lost less than 20 pounds and 36 % ( 95 % confidence interval -49 % to -20 % ) among those who lost more than 20 pounds . These results and those from our earlier study in women ( Williamson et al. , Am J Epidemiol 1995;141:1128 - 41 ) suggest that intentional weight loss may reduce the risk of dying from diabetes , but not from CVD . In observational studies , however , it is difficult to separate intentional weight loss from unintentional weight loss due to undiagnosed , underlying disease . Well- design ed observational studies , as well as r and omized controlled trials , are needed to determine whether intentional weight loss reduces CVD mortality The relation between relative weight and health differs between young and old . In older population s , weight change may cloud the association between a single relative weight and health outcomes . To determine whether weight or weight change is a more important determinant of mortality in a population of older adults , the authors analyzed data from the Systolic Hypertension in the Elderly Program ( 1984 - 1990 ) , a r and omized clinical trial testing the efficacy of antihypertensive drug treatment to reduce the risk of stroke in older adults ( aged 60 years or more ) with isolated systolic hypertension . After adjustment for covariates , an average annualized weight loss of at least 1.6 kg/year ( odds ratio = 4.9 ) , a weight loss between 1.6 and 0.7 kg/year ( odds ratio = 1.7 ) , a weight gain of more than 0.5 kg/year ( odds ratio = 2.4 ) , and a baseline body mass index of less than 23.6 ( odds ratio = 1.4 ) all had a significant ( p < 0.05 ) association with all-cause mortality compared with a referent group that was weight stable and of intermediate body mass index ( 23.6 to < 28.0 kg/m(2 ) ) and weight change ( -0.7 to < 0.5 kg/year ) . The authors 
    Output:
    
Unintentional weight loss had a significant impact on all-cause mortality .
We found no protective effect of being overweight or obese for unintentional weight loss and MACE