***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 : Because risk perceptions can affect protective behavior and protective behavior can affect risk perceptions , the relations between these 2 constructs are complex and incorrect tests often lead to invalid conclusions . Purpose : To discuss and carry out appropriate tests of 3 easily confused hypotheses : ( a ) the behavior motivation hypothesis ( perceptions of personal risk cause people to take protective action ) , ( b ) the risk re appraisal hypothesis ( when people take actions thought to be effective , they lower their risk perceptions ) , and ( c ) the accuracy hypothesis ( risk perceptions accurately reflect risk behavior ) . Methods : Longitudinal study with an initial interview just after the Lyme disease vaccine was made publicly available and a follow-up interview 18 months later . R and om sample of adult homeowners ( N = 745 ) in 3 northeastern U.S. counties with high Lyme disease incidence . Lyme disease vaccination behavior and risk perception were assessed . Results : All 3 hypotheses were supported . Participants with higher initial risk perceptions were much more likely than those with lower risk perceptions to get vaccinated against Lyme disease ( OR = 5.81 , 95 % CI 2.63 - 12.82 , p < .001 ) . Being vaccinated led to a reduction in risk perceptions , χ2(1 , N = 745 ) = 30.90 , p < .001 , and people vaccinated correctly believed that their risk of future infection was lower than that of people not vaccinated ( OR = .44 , 95 % CI .21-.91 , p < .05 ) . Conclusions : The behavior motivation hypothesis was supported in this longitudinal study , but the opposite conclusion ( i.e. , that higher risk led to less protective behavior ) would have been drawn from an incorrect test based only on cross-sectional data . Health research ers should take care in formulating and testing risk-perception-behavior hypotheses Objective To investigate predictors of attendance in the United Kingdom  flexible sigmoidoscopy screening trial . Design Prospect i ve design in which participants completed a postal question naire before being sent their invitation for screening . Setting Welwyn Garden City and Leicester , United Kingdom . Participants A total of 2758 patients aged 55 to 64 , registered with general practice s in the two centres , who ( a ) expressed interest in having the screening test , ( b ) completed a postal question naire , and ( c ) were subsequently invited for screening .  Main results The attendance rate among question naire responders was 76.1 % . Multiple logistic regression analysis yielded a final model that included nine independent predictors of attendance .  Patients with the following characteristics were more likely to attend : men ; home owners ; non-smokers ; those who had regular check ups at the dentist ; those with better subjective health ; those who minded less about having medical tests ; those who said they would definitely rather than probably take up the offer of sigmoidoscopy screening ; and those who perceived less barriers and more benefits to having the test . Conclusions The findings are broadly consistent with previous studies of screening participation , although subjective health emerged as an important predictor in this study . There was no evidence for “ reverse targeting ” : attenders were not at lower ( or higher ) risk for colorectal cancer compared with non-attenders . The findings relating to attitudes and beliefs could be used in efforts to improve attendance , for example by developing information leaflets that address barriers to screening . Other findings could be used to target interventions to subgroups that have relatively low rates of screening participation OBJECTIVE To examine the relationship between health beliefs and attitudes toward colorectal cancer screening , strength of family history risk , and being appropriately screened for colorectal cancer . METHODS In February 2004 , 7000 r and omly selected members of a multi-specialty group practice located in Boston , MA were mailed a brief survey that was used to ascertain colorectal cancer family history . A follow-up survey that contained questions representing selected constructs of the Health Belief Model , Theory of Planned Behavior , and healthcare experiences was then mailed to all 355 individuals who reported a family history in the initial survey and 710 r and omly selected participants with no colorectal cancer family history . RESULTS Participants who were appropriately screened had higher mean scores for perceived cancer risk , subjective norms , and perceived benefits and lower scores for perceived barriers . Multivariate findings indicate that having high perceptions of risk for colorectal cancer was a significant correlate of being screened appropriately among individuals with a strong family history . CONCLUSIONS For those at greatest colorectal cancer risk due to family history , ensuring that these individuals underst and their personal risk might lead to increased colorectal cancer screening participation . Future intervention research is warranted to examine if raising perceptions of risk can increase screening behaviors in individuals with colorectal cancer risk due to family history Risk perception may be an important motivator of health-related behaviors . To develop effective risk communication messages , it is important to underst and both the patterns of association between perceived risk and health-related behaviors as well as the correlates of risk perception . Very little is known about whether correlates of risk perception are similar in cross-sectional data compared with prospect i ve data . Furthermore , there are scant data on consistency of correlates of risk perception across groups who vary in objective medical risk . If correlates differ , it would underscore the need to tailor intervention messages based on subgroup characteristics as well as increase awareness of the limitations of basing intervention messages only on cross-sectional data . We analyzed data on a subset of 5042 employees who participated in The Next Step Trial , a r and omized health promotion trial to encourage colorectal cancer screening and dietary change .  We restricted our analysis to only those automotive workers who were white , male , and did not have colorectal cancer ( 4477/5042 ) and who returned surveys both at baseline ( 2,684/4,477 ) and at year 2 of follow-up ( 1955/2684 ) . Initial analyses detected interactions between a history of polyps and several of the other covariates . Therefore , univariate and multivariable analyses were conducted separately for men with and without a personal history of colorectal polyps . Within each of the four subgroups ( those with or without polyps in the baseline or follow-up analyses ) , we examined associations between perceived risk measured at baseline ( cross-sectional analyses ) and at year 2 of follow-up ( prospect i ve analyses ) in relation to intervention group status , demographic , medical history , psychosocial , and worksite characteristics measured at baseline . To assess the predictive ability of the models , we computed sensitivity and specificity as measures of each model 's ability to correctly classify men into their respective subgroup . Although there was no association between perceived risk and intervention group  status in the four subgroups analyzed , we included intervention group status as a covariate in all analyses . At baseline ( cross-sectional analyses ) among men with and without a history of polyps , perceived risk was positively associated with family history of colorectal polyps or cancer , family support for screening , and worry about being diagnosed with colorectal cancer . In addition , for men without polyps , perceived risk was positively associated with being a current smoker . At year 2 of follow-up ( prospect i ve analyses ) for men with and without polyps , perceived risk at year 2 was positively associated with family history and baseline perceived risk and was negatively associated with having a normal screening examination or no examinations during the trial . In addition , for men with polyps , perceived risk was positively associated with belief in the salience and coherence of screening and with intention to be screened and was negatively associated with access to screening at the worksite . Specificity was higher than sensitivity in three of four subgroups and was > 65 % in all subgroups . Except for family history , messages to influence perceived risk would emphasize different factors , depending on whether associations were based on baseline or follow-up data and depending on whether men reported a personal history of polyps . For example , although intervention messages using baseline data would emphasize the same factors for men with or without polyps , messages based on follow-up data would emphasize psychosocial characteristics , such as salience and coherence of screening and intention for men with a history of polyps but not for men without . Our findings support the need to delineate subgroups in the study population to target and tailor health-related messages based on respondent characteristics . Our findings also underscore the need to base health-related messages on prospect i ve data as well as cross-sectional data to better address health-related beliefs and behaviors Background : Evidence about the accuracy of self-reports of colorectal cancer ( CRC ) screening is lacking . We conducted a validation protocol in a r and omized trial to increase CRC screening among high-risk individuals . Methods : First-degree relatives ( n = 1,280 ) of CRC cases who were due for CRC screening were included in the parent trial . All subjects who completed the follow-up interview ( n = 948 ) were asked to participate in validation activities . Self-reports of receipt of CRC screening during the 12-month study period were verified via physicians . Results : Although 60 % ( n = 567 ) verbally agreed , only 171 subjects ( 18 % of original sample ) returned the signed validation form with the physician name and contact information and a medical information release statement . The signed forms were mailed to physicians with a $ 10 incentive and the request to list the date s of recent CRC screening tests . One hundred twenty-three physicians ( 72 % of physicians contacted , 13 % of original sample ) returned completed validation forms . Rates of agreement were low across all three screening types with physicians verifying self-reported screening for 29 % of fecal occult blood testing , 56 % of sigmoidoscopy , 55 % of colonoscopy , and 57 % of any screening test . Conclusion : Validation of self-report using the type of protocol we used for subjects receiving medical care in many community setting s may be unfeasible and cost inefficient . Given the overall low participation rate in validation activities and considerable challenges in collecting high quality data , conclusions about the accuracy of self-reported CRC screening are difficult to make based on the results of this study . ( Cancer Epidemiol Biomarkers Prev 2008;17(4):791–8 BACKGROUND Morbidity and mortality from colorectal cancer ( CRC ) are heightened among the socioeconomically disadvantaged . METHOD A r and omized controlled trial was conducted to evaluate the efficacy of a videotaped intervention using peer educators as well as a health professional to increase compliance with  fecal occult blood test  ( FOBT )  screening . Participants were 160 older individuals attending a medical outpatient clinic .  Compliance with FOBT use was the dependent measure . Demographic variables , family history of CRC , viewing the videotape , perceived risk , self-efficacy , physician recommendation , knowledge about CRC screening , and intent to use the FOBT were independent measures . RESULTS Approximately 41 % of participants complied with FOBT screening . Significant relationships were found between intent and family history of CRC , viewing the video , perceived risk , self-efficacy , and CRC knowledge . However , none of these variables was significantly related to compliance with FOBT use . CONCLUSIONS Although modest compliance rates were shown for both experimental and control groups , their compliance did not differ significantly . Further investigation of the impact of a video as part of an enhanced intervention program should be considered Abstract The present study was design ed to assess ethnic disparities in CRC screening rates in a low-income population and to examine factors that could account for those differences . Participants were r and omly selected and asked to complete a question naire about CRC screening . After controlling for gender , age , education , income , health insurance , and family history of CRC , differences in screening rates as a function of ethnicity remained . Physicians ' recommendations and perceived efficacy of screening were also strong predictors of CRC screening .  Psychological factors accounted in part for differences in screening rates between European Americans and Mexican Americans For years , physicians and their patients have decided , on an individual basis , whether or not to use a prostate-specific antigen ( PSA ) screening test , which can detect not only life-threatening prostate cancer but also many cancers that may never pose a danger . No clear evidence exists for whether the test provides more benefit or harm , given the aggressive treatments that often follow a positive cancer diagnosis , and so patients and physicians face a difficult choice about whether to use the test . Without definitive data , the U.S. Preventive Services Task Force ( USPSTF ) , part of the federal Agency for Healthcare Research and Quality , issued guidelines in 1996 and again in 2002 that said it can not recommend for or against PSA testing . Many other organizations that provide guidance to physicians ordering PSA tests — such as the American Cancer Society , the American College of Physicians , and the American Academy of Family Physicians (AAFP)—also adopted this position . Despite the lack of evidence , the PSA test became popular , especially for older men . In 2006 , more than 58 % of men aged 50–59 years had a PSA test within the past 2 years , according to prevalence data compiled by the U.S. Centers for Disease Control and Prevention . Older men used the test much more often . The Centers for Disease Control reported that 72 % of men aged 60–64 years had had a PSA test , and for men aged 65 years and older , it was almost 77 % . PSA testing has also led to unprecedented rates of treatment for prostate cancer : More than 90 % of men diagnosed with the disease receive some form of treatment , even though many research ers believe that most prostate cancer cases will never become a health issue . Only about one-sixth of patients diagnosed with prostate cancer ultimately succumb to the disease , but there is no way currently to identify which prostate cancers should be treated aggressively . Now , citing new findings , the USPSTF has recommended that men aged 75 years and older not be screened with the PSA test , and it reiterates that the benefits of the test are still unproven in younger ages . The USPST 
    Output:
    
We found a small , positive relationship between CRC risk perception and reported screening behavior , with important identified heterogeneity across moderators .