***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 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 Studies have reported a higher mortality risk associated with weight loss , particularly in middle-aged and older adults , although some of these studies did find that gaining weight was also associated with an increased mortality risk . We examined changes in weight  in relation to mortality in a prospect i ve population -based cohort study of men and women , resident in Norfolk , UK . Participants were assessed at baseline ( 1993–1997 ) and at a second examination ( 1998–2000 ) , as part of the European Prospect i ve Investigation into Cancer and Nutrition ( EPIC-Norfolk ) study , and followed up to 2015 for mortality . Participants with a self-reported history of cancer or cardiovascular disease , body mass index < 18.5 kg/m2 or missing data on adjustment variables , at either time-point were excluded , leaving 12,580 participants , aged 39–78 in 1993–1997 , eligible for analyses . Cox proportional hazards models were used to determine Hazard Ratios ( HRs ) for all-cause ( 2603 deaths ) , cardiovascular ( 749 deaths ) , cancer ( 981 deaths ) , respiratory ( 226 deaths ) and other causes of mortality ( 647 deaths ) by categories of weight change . After multivariate adjustment , the HRs ( 95 % CIs ) for all-cause mortality for men and women who lost more than 5 kg were 1.85 ( 1.48–2.31 ) and 1.64 ( 1.31–2.05 ) respectively . Higher hazards were also found for specific causes of mortality and weight loss > 5 kg . Similar associations were observed after excluding deaths in the first 5 years of follow-up . Results for weight gain were inconclusive . We conclude that objective ly measured weight loss  , but not weight gain , was associated with subsequent higher mortality risk in this population -based study of middle-aged and elderly men and women . However , undiagnosed , pre-existing disease and the inability to account for weight cycling need to be remembered when interpreting these results . Unravelling the causal pathways underlying this association will require more detailed studies , including that of changes in body composition 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 OBJECTIVE The prevalence of obesity is increasing in many European countries and in the United States . This report examines the mortality and morbidity associated with being overweight and obese in the Caerphilly Prospect i ve Study and the relative effects of weight in middle age and self reported weight at 18 years . DESIGN All men aged 45 to 59 years from the town of Caerphilly , South Wales and outlying villages were identified and 2512 men were examined for the first time between 1979 and 1983 . Men were asked to recall their weight at 18 years of age ( when the majority had been examined for National Service ) so that weight then , weight at screening , and the difference could be related to their 14 year follow up from screening . A total of 2335 men could recall their weight at 18 years . By 14 years of follow up from screening 465 men had died and 382 had had coronary events . RESULTS Mean body mass index in men who reported their weight at 18 years was 22.3 ( SD 2.8 ) kg/m2 and only 41 of these men ( 1.8 % ) were classified as obese ( index ⩾ 30 kg/m2 ) . The index did not predict all cause mortality when examined by quintile . For major ischaemic heart disease ( non-fatal or fatal ischaemic heart disease ) the relative odds was 1.73 ( 95 % CI 1.21 , 2.48 ) in the top fifth of the distribution ( body mass index ⩾ 24.2 kg/m2 ) compared with the bottom fifth ( body mass index < 20.1 kg/m2 ) . In men with an index ⩾ 30 kg/m2 however , the relative odds were 2.03 ( 95 % CI , 1.03 , 4.01 ) for all cause mortality and 2.17 ( 95 % CI , 1.08 , 4.34 ) for major ischaemic heart disease , adjusted for age , smoking habit and social class . When men were recruited to the study , from 1979 to 1983 ; the mean body mass index had increased to 26.2 ( SD 3.6 ) , a mean increase of 3.9 kg/m2 or 11.2 kg ; 299 men ( 12.1 % ) were classified as obese and showed significantly increased relative odds of both all cause mortality ( 1.53 ( 95 % CI 1.14 , 2.06 ) and major ischaemic heart disease ( 1.55 ( 95 % CI 1.13 , 2.11 ) ) , adjusted for age , smoking habit and social class relative to the non-obese men . The effect of gain in weight from 18 years to recruitment was also examined ; all cause mortality showed highest mortality in the fifth of the distribution who experienced weight loss or minimal weight gain . For major ischaemic heart disease an inconsistent , weak trend was shown , the relative odds rising to a maximum of 1.26 ( 0.89 , 1.80 ) in the top fifth of weight gain compared with the bottom fifth . Weight gain showed strong associations with potential cardiovascular risk factors measured at recruitment ; insulin , triglyceride , glucose , diastolic and systolic blood pressure and high density lipoprotein-cholesterol . CONCLUSIONS Body mass at 18 years of age of 30 kg/m2 or more conferred increased risk for all cause mortality and major ischaemic heart disease during 14 years of follow up of men aged 45 to 59 years . By the baseline examination the prevalence of obesity ( body mass index ⩾30 ) had increased from 1.8 % to 12.1 % ; obese men also showed an excess risk of major ischaemic heart disease and overall mortality , but these risks were lower than those predicted from 18 years of age . Weight gain was strongly associated with smoking habit , the greatest weight gain being among ex-smokers and the least among light smokers . Weight  gain from 18 years of age to baseline examination showed little relation with subsequent mortality and risk of major ischaemic heart disease when adjusted for age , smoking habit and social class . The lowest mortality rate occurred in the “ fifth ” of men who gained a mean weight of 16.1 kg . Weight gain is closely associated with some adverse cardiovascular risk factors ; in particular with insulin , triglyceride , glucose and diastolic blood pressure OBJECTIVE --To assess the validity of the 1990 US weight guidelines for women that support a substantial gain in weight at approximately 35 years of age and recommend a range of body mass index ( BMI ) ( defined as weight in kilograms divided by the square of height in meters ) from 21 to 27 kg/m2 , in terms of coronary heart disease ( CHD ) risk in women . DESIGN -- Prospect i ve cohort study . SETTING --Female registered nurses in the United States . PARTICIPANTS --A total of 115,818 women aged 30 to 55 years in 1976 and without a history of previous CHD . MAIN OUTCOME MEASURE -- Incidence of CHD defined as nonfatal myocardial infa rct ion or fatal CHD . RESULTS --During 14 years of follow-up , 1292 cases of CHD were ascertained . After controlling for age , smoking , menopausal status , postmenopausal hormone use , and parental history of CHD and using as a reference women with a BMI of less than 21 kg/m2 , relative risks ( RRs ) and 95 % confidence intervals ( CIs ) for CHD were 1.19 ( 0.97 to 1.44 ) for a BMI of 21 to 22.9 kg/m2 , 1.46 ( 1.20 to 1.77 ) for a BMI of 23 to 24.9 kg/m2 , 2.06 ( 1.72 to 2.48 ) for a BMI of 25 to 28.9 kg/m2 , and 3.56 ( 2.96 to 4.29 ) for a BMI of 29 kg/m2 or more . Women who gained weight from 18 years of age were compared with those with stable weight ( + /- 5 kg ) in analyses that controlled for the same variables as well as BMI at 18 years of age . The RRs and CIs were 1.25 ( 1.01 to 1.55 ) for a 5- to 7.9-kg gain , 1.64 ( 1.33 to 2.04 ) for an 8- to 10.9-kg gain , 1.92 ( 1.61 to 2.29 ) for an 11- to 19-kg gain , and 2.65 ( 2.17 to 3.22 ) for a gain of 20 kg or more . Among women with the BMI range of 18 to 25 kg/m2 , weight gain after 18 years of age remained a strong predictor of CHD risk . CONCLUSIONS --Higher levels of body weight within the " normal " range , as well as modest weight gains after 18 years of age , appear to increase risks of CHD in middle-aged women . These data provide evidence that current US weight guidelines may be falsely reassuring to the large proportion of women older than 35 years who are within the current guidelines but have potentially 
    Output:
    
Adult weight gain may be associated with a higher risk of CVD .
Measuring weight gain during adulthood may be better than static , cross-sectional assessment of weight because it considers trend over time , and thus , can be used as a supplementary approach to predict CVD