Cancer Epidemiology in Hispanic Populations: An Analysis of Funded Observational Research at the National Cancer Institute.

BACKGROUND: More than 62 million people self-identified as Hispanic/Latino (H/L) in the 2020 United States census. The U.S. H/L population has higher burden of certain cancers compared with their non-Hispanic White counterparts. METHODS: Key term search using the NIH Query/View/Report (QVR) system, along with Research, Condition, and Disease Categorization codes identified cancer epidemiology research grants in H/L populations funded by the NCI as a primary or secondary funder from fiscal years 2016 through 2021. Three reviewers identified eligible grants based on specified inclusion/exclusion criteria and a codebook for consistency extracting key characteristics. RESULTS: A total of 450 grants were identified through the QVR system using key words related to H/Ls; 41 cancer epidemiology grants remained after applying exclusion criteria. These grants contained specific aims focused on H/Ls (32%) or included H/Ls as part of a racial/ethnic comparison (68%). NCI was the primary funder of the majority of the grants (85%), and most of the research grants focused on cancer etiology (44%) and/or survivorship (49%). Few grants (10%) investigated environmental exposures. CONCLUSIONS: This article provides an overview of NCI-funded cancer epidemiology research in H/L populations from 2016 to 2021. Future cancer epidemiology research should reflect the changing dynamics of the U.S. demography with diverse, representative populations and well-characterized ethnicity. IMPACT: Research that carefully measures the relevant biological, environmental, behavioral, psychologic, sociocultural, and clinical risk factors will be critical to better understanding the nuanced patterns influencing cancer-related outcomes in the heterogenous H/L population.

Examining the Asian American leadership gap and inclusion issues with federal employee data: Recommendations for inclusive workforce analytic practices.

In April 2021, a coalition of employee resource groups called the Federation of Asian American, Native Hawaiian, and Pacific Islander Network, or FAN, was established at the National Institutes of Health (NIH). The coalition aims to be a unifying voice that represents and serves these diverse communities. Discussion within the group centered around the persistent inequities and the lack of inclusion that the Asian American communities have long endured. Two common themes emerged from these discussions: (1) a leadership gap for Asian Americans in senior leadership and managerial positions, and (2) the everyday experience of exclusion. Asian Americans represent nearly 20% of the NIH permanent workforce yet make up only 6% of the senior leadership positions. These two issues reflect the sentiment that Asian Americans often feel invisible or forgotten in the discourse of structural racism and organizational inequities, especially in organizations in which they are numerically overrepresented. The purpose of this manuscript is to raise awareness of Asian American concerns in the federal workforce and how current employment and workforce analytic practices in this domain might contribute to the invisibility. To accomplish this goal, we will (1) describe relevant historical and contemporary contexts of Asian American experience undergirding their inclusion and visibility concerns; (2) present data analyses from available data sources to provide a deeper understanding of the Asian American leadership gap and lack of inclusion concerns; (3) highlight data availability and analytic challenges that hinder the ability to address the inequity and invisibility issues; and (4) recommend practices in data collection, measurement, and analysis to increase the visibility of this community in the federal workforce.

Perception of worry of harm from air pollution: results from the Health Information National Trends Survey (HINTS).

BACKGROUND: Air pollution exposure has been associated with a multitude of diseases and poses a significant concern to public health. For targeted environmental risk communication and interventions to be effective, it is important to correctly identify characteristics associated with worry of harm from air pollution. METHODS: Using responses from 3,630 participants of the Health Information National Trends Survey 4 Cycle 2, we assessed worry of harm from exposure to indoor (IAP) and outdoor (OAP) air pollution separately. Multinomial logistic regression models were used to calculate odds ratios and 95% confidence intervals. RESULTS: Hispanics were more likely to worry about harm from IAP and OAP compared to non-Hispanic whites. Participants who lived in metropolitan counties were more likely to worry about harm from IAP and OAP compared to those who lived in rural counties. Finally, those who believed their chance of getting cancer was high were more likely to worry about harm from IAP and OAP compared to those who thought their likelihood of getting cancer was low. CONCLUSIONS: Worry of harm from IAP and OAP varied across sociodemographic and cancer-related characteristics. Public health professionals should consider these characteristics when developing targeted environmental risk communication and interventions.

Opportunities for Gene and Environment Research in Cancer: An Updated Review of NCI's Extramural Grant Portfolio.

BACKGROUND: The study of gene-environment (GxE) interactions is a research priority for the NCI. Previously, our group analyzed NCI's extramural grant portfolio from fiscal years (FY) 2007 to 2009 to determine the state of the science in GxE research. This study builds upon our previous effort and examines changes in the landscape of GxE cancer research funded by NCI. METHODS: The NCI grant portfolio was examined from FY 2010 to 2018 using the iSearch application. A time-trend analysis was conducted to explore changes over the study interval. RESULTS: A total of 107 grants met the search criteria and were abstracted. The most common cancer types studied were breast (19.6%) and colorectal (18.7%). Most grants focused on GxE using specific candidate genes (69.2%) compared with agnostic approaches using genome-wide (26.2%) or whole-exome/whole-genome next-generation sequencing (NGS) approaches (19.6%); some grants used more than one approach to assess genetic variation. More funded grants incorporated NGS technologies in FY 2016-2018 compared with prior FYs. Environmental exposures most commonly examined were energy balance (46.7%) and drugs/treatment (40.2%). Over the time interval, we observed a decrease in energy balance applications with a concurrent increase in drug/treatment applications. CONCLUSIONS: Research in GxE interactions has continued to concentrate on common cancers, while there have been some shifts in focus of genetic and environmental exposures. Opportunities exist to study less common cancers, apply new technologies, and increase racial/ethnic diversity. IMPACT: This analysis of NCI's extramural grant portfolio updates previous efforts and provides a review of NCI grant support for GxE research.

Next steps in studying the human microbiome and health in prospective studies, Bethesda, MD, May 16-17, 2017.

The National Cancer Institute (NCI) sponsored a 2-day workshop, "Next Steps in Studying the Human Microbiome and Health in Prospective Studies," in Bethesda, Maryland, May 16-17, 2017. The workshop brought together researchers in the field to discuss the challenges of conducting microbiome studies, including study design, collection and processing of samples, bioinformatics and statistical methods, publishing results, and ensuring reproducibility of published results. The presenters emphasized the great potential of microbiome research in understanding the etiology of cancer. This report summarizes the workshop and presents practical suggestions for conducting microbiome studies, from workshop presenters, moderators, and participants.

Association of 25-Hydroxyvitamin D with Liver Cancer Incidence and Chronic Liver Disease Mortality in Finnish Male Smokers of the ATBC Study.

Background: Although circulating 25-hydroxyvitamin D [25(OH)D] concentrations were linked to liver cancer and chronic liver disease (CLD) in laboratory studies, few epidemiologic studies have addressed the associations.Methods: Within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, we measured 25(OH)D in baseline serum of 202 incident liver cancer cases and 225 CLD deaths that occurred during nearly 25 years of follow-up, and 427 controls. ORs and 95% confidence intervals (CIs) were estimated using unconditional logistic regression. We examined predetermined clinically defined cut-points, and season-specific and season-standardized quartiles.Results: Low serum 25(OH)D concentrations were associated with higher risk of liver cancer (<25 nmol/L vs. ≥50 nmol/L: 1.98; 95% CI, 1.22-3.20; Ptrend across categories = 0.003) and CLD mortality (1.93; 95% CI, 1.23-3.03; Ptrend = 0.006) in models adjusted for age and date of blood draw. After additional adjustment for body mass index, diabetes, smoking, and other potential confounders, the association remained statistically significant for liver cancer (1.91; 95% CI, 1.16-3.15; Ptrend = 0.008), but was somewhat attenuated for CLD mortality (1.67; 95% CI, 1.02-2.75; Ptrend = 0.05). Associations were similar for analyses using season-specific and season-standardized quartiles, and after excluding participants with diabetes, or hepatitis B or C.Conclusions: Our results suggest a possible preventive role for vitamin D against liver cancer and CLD, although the importance of the liver for vitamin D metabolism and the lack of information about underlying liver disease makes reverse causality a concern.Impact: Future studies are needed to evaluate associations of vitamin D with liver cancer and liver disease in other populations, particularly those with a different constellation of risk factors. Cancer Epidemiol Biomarkers Prev; 27(9); 1075-82. ©2018 AACR.

Design and analysis of group-randomized trials in cancer: A review of current practices.

The purpose of this paper is to summarize current practices for the design and analysis of group-randomized trials involving cancer-related risk factors or outcomes and to offer recommendations to improve future trials. We searched for group-randomized trials involving cancer-related risk factors or outcomes that were published or online in peer-reviewed journals in 2011-15. During 2016-17, in Bethesda MD, we reviewed 123 articles from 76 journals to characterize their design and their methods for sample size estimation and data analysis. Only 66 (53.7%) of the articles reported appropriate methods for sample size estimation. Only 63 (51.2%) reported exclusively appropriate methods for analysis. These findings suggest that many investigators do not adequately attend to the methodological challenges inherent in group-randomized trials. These practices can lead to underpowered studies, to an inflated type 1 error rate, and to inferences that mislead readers. Investigators should work with biostatisticians or other methodologists familiar with these issues. Funders and editors should ensure careful methodological review of applications and manuscripts. Reviewers should ensure that studies are properly planned and analyzed. These steps are needed to improve the rigor and reproducibility of group-randomized trials. The Office of Disease Prevention (ODP) at the National Institutes of Health (NIH) has taken several steps to address these issues. ODP offers an online course on the design and analysis of group-randomized trials. ODP is working to increase the number of methodologists who serve on grant review panels. ODP has developed standard language for the Application Guide and the Review Criteria to draw investigators' attention to these issues. Finally, ODP has created a new Research Methods Resources website to help investigators, reviewers, and NIH staff better understand these issues.

Research Strategies for Nutritional and Physical Activity Epidemiology and Cancer Prevention.

Very large international and ethnic differences in cancer rates exist, are minimally explained by genetic factors, and show the huge potential for cancer prevention. A substantial portion of the differences in cancer rates can be explained by modifiable factors, and many important relationships have been documented between diet, physical activity, and obesity, and incidence of important cancers. Other related factors, such as the microbiome and the metabolome, are emerging as important intermediary components in cancer prevention. It is possible with the incorporation of newer technologies and studies including long follow-up and evaluation of effects across the life cycle, additional convincing results will be produced. However, several challenges exist for cancer researchers; for example, measurement of diet and physical activity, and lack of standardization of samples for microbiome collection, and validation of metabolomic studies. The United States National Cancer Institute convened the Research Strategies for Nutritional and Physical Activity Epidemiology and Cancer Prevention Workshop on June 28-29, 2016, in Rockville, Maryland, during which the experts addressed the state of the science and areas of emphasis. This current paper reflects the state of the science and priorities for future research. Cancer Epidemiol Biomarkers Prev; 27(3); 233-44. ©2017 AACR.

Nut Consumption and Lung Cancer Risk: Results from Two Large Observational Studies.

Background: Epidemiologic evidence on the association between nut consumption and lung cancer risk is limited.Methods: We investigated this relationship in the Environment and Genetics in Lung Cancer Etiology (EAGLE) study, a population-based case-control study, and the National Institutes of Health (NIH) American Association of Retired Persons (AARP) Diet and Health Study, a prospective cohort. We identified 2,098 lung cases for EAGLE and 18,533 incident cases in AARP. Diet was assessed by food frequency questionnaire for both studies. Multivariable ORs and HRs and respective 95% confidence intervals (CI) were calculated using unconditional logistic regression and Cox proportional hazards regression for EAGLE and AARP, respectively.Results: Higher frequency of intake of nut consumption was inversely associated with overall lung cancer risk (highest vs. lowest quintile, OREAGLE = 0.74; 95% CI, 0.57-0.95; HRAARP = 0.86; 95% CI, 0.81-0.91), regardless of smoking status. Results from the prospective cohort showed similar associations across histologic subtypes and a more pronounced benefits from nut consumption for those who smoked 1 to 20 cigarettes/day (OREAGLE = 0.61; 95% CI, 0.39-0.95; HRAARP = 0.83; 95% CI, 0.74-0.94).Conclusions: Nut consumption was inversely associated with lung cancer in two large population-based studies, and associations were independent of cigarette smoking and other known risk factors.Impact: To our knowledge, this is the first study that examined the association between nut consumption and lung cancer risk by histologic subtypes and smoking intensity. Cancer Epidemiol Biomarkers Prev; 26(6); 826-36. ©2017 AACR.

Higher Glucose and Insulin Levels Are Associated with Risk of Liver Cancer and Chronic Liver Disease Mortality among Men without a History of Diabetes.

Insulin resistance likely increases the risk of chronic liver disease (CLD) and liver cancer, but long-term prospective studies with measured fasting glucose and insulin are lacking. We evaluated the associations of prediagnostic fasting glucose, insulin, and the homeostasis model assessment of insulin resistance (HOMA-IR) with liver cancer and CLD mortality in a prospective study of Finnish male smokers with extended follow-up time (≤22 years) and information on known risk factors using data from 138 incident primary liver cancer cases, 216 CLD deaths, and 681 matched controls. Fasting glucose and insulin were measured in baseline serum. We used unconditional logistic regression to estimate ORs and 95% confidence intervals adjusted for age, alcohol, education, smoking, body mass index, and hepatitis B and C viral status. Among those without self-reported diabetes, glucose was positively associated with liver cancer [quartile 3 vs. quartile 1 (Q3/Q1): OR = 1.88; 1.03-3.49; Q4/Q1: OR = 2.40; 1.33-4.35; Ptrend = 0.002], and undiagnosed, biochemically defined, diabetes was associated with higher risk of liver cancer (OR = 2.95; 1.46-5.96) and CLD mortality (OR = 1.88; 1.00-3.56). Serum insulin and HOMA-IR were also positively associated with liver cancer (Q4/Q1: OR = 3.41; 1.74-6.66; Ptrend < 0.0001; OR = 3.72; 1.89-7.32, Ptrend < 0.0001, respectively) and CLD (OR = 2.51; 1.44-4.37; Ptrend = 0.0002; OR = 2.31; 1.34-3.97; Ptrend = 0.001, respectively), with stronger associations observed for liver cancer diagnosed >10 years after baseline. In conclusion, elevated fasting glucose and insulin and insulin resistance were independently associated with risk of liver cancer and CLD mortality, suggesting a potentially important etiologic role for insulin and glucose dysregulation even in the absence of diagnosed diabetes. Cancer Prev Res; 9(11); 866-74. ©2016 AACR.

The Cancer Epidemiology Descriptive Cohort Database: A Tool to Support Population-Based Interdisciplinary Research.

BACKGROUND: We report on the establishment of a web-based Cancer Epidemiology Descriptive Cohort Database (CEDCD). The CEDCD's goals are to enhance awareness of resources, facilitate interdisciplinary research collaborations, and support existing cohorts for the study of cancer-related outcomes. METHODS: Comprehensive descriptive data were collected from large cohorts established to study cancer as primary outcome using a newly developed questionnaire. These included an inventory of baseline and follow-up data, biospecimens, genomics, policies, and protocols. Additional descriptive data extracted from publicly available sources were also collected. This information was entered in a searchable and publicly accessible database. We summarized the descriptive data across cohorts and reported the characteristics of this resource. RESULTS: As of December 2015, the CEDCD includes data from 46 cohorts representing more than 6.5 million individuals (29% ethnic/racial minorities). Overall, 78% of the cohorts have collected blood at least once, 57% at multiple time points, and 46% collected tissue samples. Genotyping has been performed by 67% of the cohorts, while 46% have performed whole-genome or exome sequencing in subsets of enrolled individuals. Information on medical conditions other than cancer has been collected in more than 50% of the cohorts. More than 600,000 incident cancer cases and more than 40,000 prevalent cases are reported, with 24 cancer sites represented. CONCLUSIONS: The CEDCD assembles detailed descriptive information on a large number of cancer cohorts in a searchable database. IMPACT: Information from the CEDCD may assist the interdisciplinary research community by facilitating identification of well-established population resources and large-scale collaborative and integrative research. Cancer Epidemiol Biomarkers Prev; 25(10); 1392-401. ©2016 AACR.

Coffee Consumption and Risk of Hepatocellular Carcinoma and Intrahepatic Cholangiocarcinoma by Sex: The Liver Cancer Pooling Project.

BACKGROUND: Coffee consumption has been reported to be inversely associated with hepatocellular carcinoma (HCC), the most common type of liver cancer. Caffeine has chemopreventive properties, but whether caffeine is responsible for the coffee-HCC association is not well studied. In addition, few studies have examined the relationship by sex, and no studies have examined whether there is an association between coffee and intrahepatic cholangiocarcinoma (ICC), the second most common type of liver cancer. METHODS: In the Liver Cancer Pooling Project, a consortium of U.S.-based cohort studies, data from 1,212,893 individuals (HCC, n = 860; ICC, n = 260) in nine cohorts were pooled. Multivariable-adjusted hazard ratios (HR) and 95% confidence intervals (CI) were estimated using proportional hazards regression. RESULTS: Higher coffee consumption was associated with lower risk of HCC (HR>3 cups/day vs. non-drinker, 0.73; 95% CI, 0.53-0.99; Ptrend cups/day = <0.0001). More notable reduced risk was seen among women than men (Pinteraction = 0.07). Women who consumed more than three cups of coffee per day were at a 54% lower risk of HCC (HR, 0.46; 95% CI, 0.26-0.81), whereas men had more modest reduced risk of HCC (HR, 0.93; 95% CI, 0.63-1.37). The associations were stronger for caffeinated coffee (HR>3 cups/day vs. non-drinker, 0.71; 95% CI, 0.50-1.01) than decaffeinated coffee (HR, 0.92; 95% CI, 0.55-1.54). There was no association between coffee consumption and ICC. CONCLUSIONS: These findings suggest that, in a U.S. population, coffee consumption is associated with reduced risk of HCC. IMPACT: Further research into specific coffee compounds and mechanisms that may account for these associations is needed.

Association of seropositivity to Helicobacter species and biliary tract cancer in the ATBC study.

UNLABELLED: Helicobacter have been detected in human bile and hepatobiliary tissue. Despite evidence that Helicobacter species promote gallstone formation and hepatobiliary tumors in laboratory studies, it remains unclear whether Helicobacter species contribute to these cancers in humans. We used a multiplex panel to assess whether seropositivity to 15 Helicobacter pylori proteins was associated with subsequent incidence of hepatobiliary cancers in the Finnish Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. We included 64 biliary cancers, 122 liver cancers, and 224 age-matched controls which occurred over the course of 22 years. Helicobacter pylori seropositivity was defined as those positive to ≥ 4 antigens. Odds ratios (OR) and 95% confidence intervals were adjusted for major hepatobiliary cancer risk factors. Among the controls, 88% were seropositive to H. pylori at baseline. Among those who subsequently developed hepatobiliary cancer, the prevalence of seropositivity was higher: 100% for gallbladder cancer, 97% of extrahepatic bile duct cancer, 91% of ampula of Vater cancer, 96% of intrahepatic bile duct cancer, and 94% of hepatocellular carcinoma. Although the OR for gallbladder cancer could not be calculated, the OR for the other sites were 7.01 (95% confidence interval [CI]: 0.79-62.33), 2.21 (0.19-25.52), 10.67 (0.76-150.08), and 1.20 (0.42-3.45), respectively, with an OR of 5.47 (95% CI: 1.17-25.65) observed for the biliary tract cancers combined. ORs above 1 were observed for many of the investigated antigens, although most of these associations were not statistically significant. CONCLUSION: Seropositivity to H. pylori proteins was associated with an increased risk of biliary tract cancers in ATBC. Further studies are needed to confirm our findings and to determine how H. pylori might influence the risk of biliary tract cancer.

Association of C-peptide and leptin with prostate cancer incidence in the Health Professionals Follow-up Study.

PURPOSE: Hyperinsulinemia is hypothesized to influence prostate cancer risk. Thus, we evaluated the association of circulating C-peptide, which is a marker of insulin secretion, and leptin, which is secreted in response to insulin and influences insulin sensitivity, with prostate cancer risk. METHODS: We identified prostate cancer cases (n = 1,314) diagnosed a mean of 5.4 years after blood draw and matched controls (n = 1,314) in the Health Professionals Follow-up Study. Plasma C-peptide and leptin concentrations were measured by ELISA. Odds ratios (ORs) and 95 % confidence intervals (CI) were estimated taking into account the matching factors age and history of a PSA test before blood draw and further adjusting for body mass index, diabetes, and other factors. RESULTS: Neither C-peptide (quartile [Q]4 vs. Q1: OR 1.05, 95 % CI 0.82-1.34, p-trend = 0.95) nor leptin (Q4 vs. Q1: OR 0.85, 95 % CI 0.65-1.12, p-trend = 0.14) was associated with prostate cancer risk. Further, neither was associated with risk of advanced or lethal disease (n = 156 cases; C-peptide: Q4 vs. Q1, OR 1.18, 95 % CI 0.69-2.03, p-trend = 0.78; leptin: Q4 vs. Q1, OR 0.74, 95 % CI 0.41-1.36, p-trend = 0.34). CONCLUSIONS: In this large prospective study, circulating C-peptide and leptin concentrations were not clearly associated with risk of prostate cancer overall or aggressive disease. Well into the PSA era, our findings do not appear to be supportive of the hypothesis that hyperinsulinemia influences risk of total or aggressive prostate cancer.

The association between self-reported diabetes and cancer incidence in the NIH-AARP Diet and Health Study.

CONTEXT: Epidemiological studies have observed associations between diabetes and a number of different cancers. Yet the association with cancer overall and the interrelationship of diabetes and obesity with cancer have been unclear. OBJECTIVE, DESIGN, SETTING, AND PARTICIPANTS: We evaluated the association between self-reported diabetes and cancer incidence in the NIH-AARP (National Institutes of Health-American Association of Retired Persons) Diet and Health Study, a prospective cohort in which 295,276 men and 199,591 women completed a questionnaire in 1995-1996 and were followed up for cancer through 2006. MAIN OUTCOME MEASURES: Hazard ratios (HRs) and 95% confidence intervals (CIs) for cancer incidence, overall and by type, were estimated from multivariate Cox proportional hazards models. RESULTS: Diabetes was positively associated with total incident cancer in women (1.07, 95% CI 1.02-1.12) but inversely in men (0.96, 95% CI 0.93-0.98). However, diabetes was inversely associated with prostate cancer (HR 0.74, 95% CI 0.70-0.78), which constituted 42% of cancers in men. After excluding prostate cancer, diabetes was also positively associated with cancer in men (HR 1.09, 95% CI 1.04-1.14). By site, diabetes was positively associated with anal, bladder, colon, kidney, liver, pancreatic, rectal, and stomach cancers and in women with endometrial cancer. We also evaluated the joint effect of obesity and diabetes and observed that diabetes conferred additional risk, beyond that of overweight or obesity, for cancer overall, excluding prostate, and for certain sites including the bladder, colon, endometrium, kidney, liver, pancreas, rectum, and stomach. CONCLUSION: Our results suggest an etiological role for diabetes in a number of cancers, independent of obesity, and that preventing diabetes may contribute to reduced cancer risk.

Racial variation in umbilical cord blood leptin concentration in male babies.

BACKGROUND: We hypothesize that racial differences in utero contribute to the racial disparity in prostate cancer risk. Leptin is a candidate for evaluating this hypothesis because it influences fetal development and newborn growth. METHODS: We measured leptin concentration by ELISA in venous cord blood collected from 70 African-American and 37 white male full-term babies. We measured sex steroid hormones and insulin-like growth factor (IGF) axis concentrations previously. Separately by race, we calculated the geometric mean leptin concentration and estimated the geometric mean adjusted for birth and placental weights, mother's age and parity, time of day and season of birth, and sex steroid hormone and IGF axis concentrations by linear regression. RESULTS: Leptin was positively correlated with birth (r = 0.34) and placental (r = 0.25) weights, IGF-1 (r = 0.21), and IGF binding protein-3 (r = 0.29) adjusting for race. Unadjusted geometric mean leptin did not differ (P = 0.92) between African Americans (5,280 pg/mL; 95% CI: 4,322-6,451) and whites (5,187 pg/mL; 95% CI: 3,938-6,832). Adjusted geometric mean leptin was nonstatistically significantly higher (P = 0.15) in African Americans (5,954 pg/mL; 95% CI: 4,725-7,502) than in whites (4,133 pg/mL; 95% CI: 2,890-5,910). CONCLUSION: We observed a nonsignificantly higher adjusted cord blood leptin concentration in African-American male babies than in white male babies, although unadjusted levels were similar. IMPACT: These findings do not support the hypothesis that leptin level in utero contributes to the racial disparity in prostate cancer risk in adulthood.

Association between C-peptide concentration and prostate cancer incidence in the CLUE II cohort study.

Diabetes, characterized by perturbations in insulin production and signaling, is inversely associated with prostate cancer risk irrespective of stage. Obesity, a diabetes risk factor, is inversely associated with localized disease but positively associated with advanced disease. To understand the complex association between hyperinsulinemia and prostate cancer, we evaluated the association of plasma C-peptide, an insulin secretion marker, with prostate cancer risk in a case-control study nested in a prospective community cohort. Prostate cancer cases (n = 264) and matched controls (n = 264) were identified in the CLUE II cohort between 1989 (baseline) and 2002. C-peptide concentration was measured in baseline plasma by ELISA. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using conditional logistic regression, adjusting for being overweight or obese and family history. Median C-peptide concentration was lower in cases (1,180 pmol/L) than in controls (1,365 pmol/L; P = 0.03). Men in the highest (versus lowest) fourth of C-peptide had a lower risk for prostate cancer (OR, 0.65; 95% CI, 0.37-1.14; P-trend = 0.08), primarily localized disease (OR, 0.44; 95% CI, 0.19-1.03; P-trend = 0.04). Associations were similar to overall, when excluding cases diagnosed during the first 5 years of follow-up, men with diabetes, or men who had not had a prostate-specific antigen test. C-peptide concentration was inversely associated with subsequent diagnosis of prostate cancer, primarily localized disease, similar to the association for obesity. However, we cannot rule out detection bias that might result if men with higher C-peptide have lower prostate-specific antigen irrespective of whether prostate cancer is present or not.

Barriers to recruiting underrepresented populations to cancer clinical trials: a systematic review.

Racial and ethnic minorities, older adults, rural residents, and individuals of low socioeconomic status are underrepresented among participants in cancer-related trials. The authors conducted a systematic review to determine the barriers to participation of underrepresented populations in cancer-related trials. Their search included English-language publications that reported original data on the recruitment of underrepresented groups to cancer treatment or prevention trials between 1966 and December 2005 in multiple electronic databases. They also hand-searched titles in 34 journals from January 2003 to December 2005 and they examined reference lists for eligible articles. Titles and abstracts were reviewed to identify relevant studies. Data on barriers to participation were synthesized both qualitatively and based on statistically significant associations with trial enrollment. Of 5257 studies that were cited, 65 studies were eligible for inclusion in the current analysis, including 46 studies on recruitment into cancer therapeutic trials, 15 studies on recruitment into prevention trials, and 4 studies on recruitment into both prevention and treatment trials. Numerous factors were reported as barriers to participation in cancer-related trials. However, only 20 of the studies reported statistically significant associations between hypothesized barriers and enrollment. The available evidence had limitations in quality regarding representativeness, justification of study methods, the reliability and validity of data-collection methods, potential for bias, and data analysis. The results indicated that underrepresented populations face numerous barriers to participation in cancer-related trials. The current systematic review highlighting the literature on recruitment of underrepresented populations to cancer trials and may be used as the evidence base toward developing an agenda for etiologic and intervention research to reduce the disparities in participation in cancer-related trials.

Applying justice in clinical trials for diverse populations.

BACKGROUND: Considerable attention has focused on increasing clinical trial participation for members of "underrepresented groups". However, doing so involves clarifying how to meet the demands of justice, or fairness, which provides the ethical mandate to enhance broad trial representation. PURPOSE: To examine the ethical principle of justice as it applies to recruiting diverse populations to clinical trials representation. METHODS: In this paper, we analyse the conceptual and practical challenges in applying the principle of justice to clinical trials representation. RESULTS: Different facets of justice include demands for both fair outcomes and fair processes. Including both of these facets in clinical trials policy should not only promote access to trials, but also help to provide a framework to improve fairness in representation in clinical trials. Efforts to evaluate recruitment of representation should include outcome and process measures. LIMITATIONS: The suggestions offered based on this conceptual analysis need to be tested empirically. CONCLUSIONS: Those involved in the design, conduct and oversight of clinical trials should consider all of the facets of justice when assessing representation in clinical trials and attempt to balance fair access to trials with a fair process that may require protection from being unduly pressured to participate.

Provider roles in the recruitment of underrepresented populations to cancer clinical trials.

BACKGROUND: Providers play a vital role in the successful recruitment of underrepresented patients to cancer clinical trials because they often introduce the opportunity of clinical trials. The purpose of the current systematic review was to describe provider-related factors influencing recruitment of underrepresented populations to cancer clinical trials. METHODS: To find original studies on the recruitment of underrepresented populations to cancer clinical trials, electronic databases from January 1966 to December 2005 were searched; hand-searched titles in 34 journals from January 2003 to January 2006; and reference lists were examined of eligible articles. Title and abstract reviews were conducted to identify relevant studies. Potential articles were then abstracted using a structured instrument and a serial review process by 2 investigators. RESULTS: Eighteen studies were eligible for review: 13 targeted healthcare providers, 3 targeted patients/participants, and 2 targeted both providers and patients. The study designs included randomized controlled trial, concurrent controlled trial, case-control, descriptive, and qualitative. A lack of available protocols and/or a lack of provider awareness about clinical trials prevented providers from discussing the opportunity of clinical trials in 2 studies. In 14 studies, patient accrual was affected by provider attitudinal barriers relating to patient adherence to the study protocol, patient mistrust of research, patient costs, data collection costs, and/or patient eligibility. Providers' communication methods were barriers in 5 studies and promoters in 1 study. CONCLUSIONS: A heterogeneous body of evidence suggests that several provider-related factors influence recruitment of underrepresented groups to clinical trials. Future recruitment efforts should address these factors.