***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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    Input: Results from case-control studies and prospect i ve studies suggest that diet is involved in the causation of large bowel cancer either as initiator , promoter or inhibitor of carcinogenesis . Available data are not sufficient to serve as a basis for firm specific dietary advice . In the present situation it is attractive to investigate available hypotheses within the frame work of intervention trials . The adenoma appears to be one of the most appropriate end point of intervention studies . Several arguments indicate that the adenoma-carcinoma sequence is a multistep process . Colorectal cancer could possibly be prevented by intervening in the development of a small adenoma or in the growth into a large adenoma . Four intervention trials have been published so far . One of them suggest a protective effect of antioxidants vitamins  on adenoma recurrence and three of them conclude to the absence of effect of these vitamins . A protective effect of  lactulose  on adenoma recurrence has also been suggested . Three studies are currently evaluating the effect of  calcium supplementation  on adenoma recurrence or growth of calcium supplementation  , three studies the effect of fibre supplements , two studies the effect of antioxidants ( one of them with calcium ) and two studies the effect of  diet intervention . The results of these studies will be available within three years BACKGROUND The Polyp Prevention Trial ( PPT ) was a multicenter r and omized clinical trial design ed to determine the effects of a high-fiber ( 4.30 g/MJ ) , high-fruit- and -vegetable ( 0.84 servings/MJ ) , low-fat ( 20 % of energy from fat ) diet on the recurrence of adenomatous polyps in the large bowel . OBJECTIVE Our goal was to determine whether the PPT intervention plan could effect change in 3 dietary goals and to examine the intervention 's effect on the intake of other food groups and nutrients . DESIGN Participants with large-bowel adenomatous polyps diagnosed in the past 6 mo were r and omly assigned to either the intervention ( n = 1037 ) or the control ( n = 1042 ) group and remained in the trial for 4 y. Three dietary assessment instruments were used to measure dietary change : food-frequency question naires ( in 100 % of the sample ) , 4-d food records ( in a 20 % r and om cohort ) , and 24-h dietary recalls ( in a 10 % r and om sample ) . RESULTS Intervention participants made and sustained significant changes in all PPT goals as measured by the dietary assessment instruments ; the control participants ' intakes remained essentially the same throughout the trial . The absolute differences between the intervention and control groups over the 4-y period were 9.7 % of energy from fat ( 95 % CI : 9.0 % , 10.3 % ) , 1.65 g dietary fiber/MJ ( 95 % CI : 1.53 , 1.74 ) , and 0.27 servings of fruit and vegetables/MJ ( 95 % CI : 0.25 , 0.29 ) . Intervention participants also reported significant changes in the intake of other nutrients and food groups . The intervention group also had significantly higher serum carotenoid concentrations and lower body weights than did the control group . CONCLUSION Motivated , free-living individuals , given appropriate support , can make and sustain major dietary changes over a 4-y period Adherence determinants and key adherence research issues are discussed for three types of r and omized controlled trials : pharmacological , dietary , and physical activity . This article highlights theoretical and method ological limitations that have hampered the ability to identify patients at risk for poor treatment compliance . Control Clin Trials Objective To evaluate the impact of a diet and physical activity intervention ( BeWEL ) on weight change in people with a body mass index > 25 weight (kg)/height (m)2 at increased risk of colorectal cancer and other obesity related comorbidities . Design Multicentre , parallel group , r and omised controlled trial . Setting Four Scottish National Health Service health boards . Participants 329 overweight or obese adults ( aged 50 to 74 years ) who had undergone colonoscopy after a positive faecal occult blood test result , as part of the national bowel screening programme , and had a diagnosis of adenoma confirmed by histopathology . 163 were r and omised to intervention and 166 to control . Intervention Participants were r and omised to a control group ( weight loss booklet only ) or 12 month intervention group ( three face to face visits with a lifestyle counsellor plus monthly 15 minute telephone calls ) . A goal of 7 % reduction in body weight was set and participants received a personalised energy prescription ( 2508 kJ ( 600 kcal ) below that required for weight maintenance ) and bodyweight scales . Motivational interviewing techniques explored self assessed confidence , ambivalence , and personal values concerning weight . Behavioural strategies included goal setting , identifying intentions of implementation , self monitoring of body weight , and counsellor feedback about reported diet , physical activity , and weight change . Main outcome measures The primary outcome was weight change over 12 months . Secondary outcomes included changes in waist circumference , blood pressure , fasting cardiovascular biomarkers , and glucose metabolism variables , physical activity , diet , and alcohol consumption . Results At 12 months , data on the primary outcome were available for 148 ( 91 % ) participants in the intervention group and 157 ( 95 % ) in the control group . Mean weight loss was 3.50 kg ( SD 4.91 ) ( 95 % confidence interval 2.70 to 4.30 ) in the intervention group compared with 0.78 kg ( SD 3.77 ) ( 0.19 to 1.38 ) in the control group . The group difference was 2.69 kg ( 95 % confidence interval 1.70 to 3.67 ) . Differences between groups were significant for waist circumference , body mass index , blood pressure , blood glucose level , diet , and physical activity . No reported adverse events were considered to be related to trial participation . Conclusions Significant weight loss can be achieved by a diet and physical activity intervention initiated within a national colorectal cancer screening programme , offering considerable potential for risk reduction of disease in older adults . Trial registration Current Controlled Trials IS RCT N53033856 Westernization or industrialization leads to an increase in rates of colon cancer , which is the second leading cause of malignant death in the United States [ 1 ] . Although the precise causes of colon cancer remain unclear , a diet high in red meat or animal fat and low in fruits and vegetables appears to increase the risk for this malignancy [ 2 , 3 ] . It is perhaps less well recognized that an inverse association between physical activity and risk for colon cancer has been seen in studies of occupational activity only [ 4 - 12 ] and of both job-related and recreational activity [ 13 - 23 ] . In addition , many studies have found an association between body mass and elevated risk for colon cancer in men ; this association is weaker in women [ 24 - 33 ] . The fact that the association is stronger in men suggests that the abdominal distribution of adiposity typical in men may be an important component of enhanced risk . More limited evidence suggests that height , which may be a proxy for a person 's net energy intake during childhood and adolescence , is related to a higher risk for colon cancer [ 33 - 35 ] . We examine the association between physical activity , obesity , and attained height in relation to risk for colon cancers and their precursory adenomas in a large cohort of male health professionals in the United States . Waist and hip circumferences were available for a subcohort of the study population . We address the hypotheses that physical inactivity , obesity , and height increase the risk for colon cancer and adenoma independently of each other and of diet , and that the abdominal pattern of obesity is an additional independent risk factor . Methods Study Population The Health Professionals Follow-up Study [ 36 ] was started in 1986 ; in that year , 51 529 male dentists , optometrists , osteopaths , podiatrists , pharmacists , and veterinarians in the United States between 40 and 75 years of age responded to a mailed question naire . They reported on their leisure-time physical activity ( described below ) ; current body weight ; weight at age 21 years ; height ; history of cancer and other medical conditions ; parental history of various diseases , including colorectal cancer ; and use of aspirin and other nonsteroidal anti-inflammatory medications . They also reported dietary and alcohol intake using a vali date d [ 37 , 38 ] , semi-quantitative food-frequency question naire . We mailed an optional question naire in 1987 to assess  waist and hip circumferences . In 1988 , 1990 , and 1992 , we up date d exposure information and ascertained newly diagnosed medical conditions and history of colonoscopy or sigmoidoscopy , including the indications for endoscopy : bleeding in stool , positive results from tests for occult fecal blood , abdominal pain , diarrhea or constipation , family history of colorectal cancer , routine screening without symptoms , or follow-up [ 39 ] . Most of the deaths in the cohort were reported by family members or by the postal system in response to the follow-up question naires . We also used the National Death Index to identify deaths among nonrespondents [ 40 ] . Assessment of Physical Activity The 1986 question naire included a section about mainly recreational or leisure-time physical activity . The reliability and validity of question naires design ed to assess physical activity have been investigated [ 41 - 43 ] . A question naire such as the one used in our cohort was evaluated in a cohort of U.S. nurses and was found to provide useful information [ 44 ] , and similar results were found during a similar validation study done within the Health Professionals cohort ( Chasan-Taber S. Personal communication ) . Participants reported the average time per week spent doing each of eight moderate and vigorous activities , choosing from among 10 possible responses that ranged from 0 minutes to 11 or more hours per week . The specific activities listed were walking or hiking outdoors ( including walking during golf ) ; jogging ( slower than 10 minutes/mile ) ; running ( 10 minutes/mile or faster ) ; bicycling ( including that done on a stationary machine ) ; lap swimming ; tennis , squash , or racquetball ; and calisthenics or rowing . In addition , each respondent reported the number of flights of stairs he climbed daily and his usual walking pace . The reported time spent at each activity per week was multiplied by its typical energy expenditure requirements expressed in metabolic equivalents ( METs ) [ 45 ] to yield a MET-hour score . One MET , which is the energy expended by sitting quietly , is equivalent to 3.5 mL of oxygen uptake per kilogram of body weight per minute for a 70-kg adult . For example , 1 hour per week of running contributed 10.2 MET-hours , 1 hour of tennis contributed 6 MET-hours , and 1 hour of walking at a moderate pace contributed 3.2 MET-hours . Body weight was excluded from the derivation of energy expenditure from physical activity to avoid confounding the expenditure variable by body weight . If more than one published intensity level was available for a given activity , the moderate or general MET value was chosen . An average MET value was assigned to the categories that listed more than one activity , such as rowing or calisthenics , and squash or racquetball . Assessment of Anthropometric Variables  Each man reported his current weight and height and his weight at age 21 years on the 1986 question naire . In 1987 , we mailed an optional question naire once to obtain additional exposure information , including body circumference measurements . We instructed each participant to measure ( to the nearest quarter inch ) his waist at the umbilicus and his hips at the largest circumference between the waist and thighs while st and ing and without measuring over bulky clothing [ 46 ] . We provided a tape measure and an illustration to help st and ardize the measurements . Sixty-five percent of the cohort responded . We used the Quetelet index ( kilograms/height in meters2 ) as a measure of total adiposity , waist-to-hip ratio to measure relative distribution of fat , and waist circumference to estimate total abdominal fat . Although the waist-to-hip ratio has been used more widely , waist circumference provides an estimate of absolute abdominal adiposity , the component most closely related to important metabolic abnormalities , including hyperinsulinemia , hypertension , and high triglyceride levels . To remove extraneous variation in the waist circumference because of height ( taller men tend to have larger waist circumferences due to their larger body size rather than to obesity ) , we adjusted waist for height using residual analysis [ 47 ] . We first regressed waist on height using multiple linear regression and then added the residual to the average waist size ( 37.4 inches ) for a man of average height ( 70 inches ) to convert this measure back to the initial scale . This conversion created for each man a st and ardized waist circumference unconfounded by height . We evaluated the precision of self-reported anthropometric measures among 123 cohort members who were part of a dietary validation study [ 46 ] . Trained technicians paid the sub study participants two visits , approximately 6 months apart , to measure current weight and waist and hip circumferences . The Pearson correlation between self-report and the average of the technicians ' two measurements was 0.97 for weight , 0.95 for waist circumference , 0.88 for hip circumference , and 0.69 for waist-to-hip ratio . The men 's self- measurements of their waist circumferences were 0.36 inches greater , their self- measurements of hip circumferences were 0.78 inches smaller , and their self- 
    Output:
    
Conclusions The findings of this review indicate that behavioural interventions can encourage colorectal adenoma patients to improve their diet .
This review was not however able to clearly characterise effective interventions promoting increased physical activity in this patient group .