Challenges and strategies for recruitment of minorities to clinical research and trials.

Minority populations are largely absent from clinical research trials. The neglect of these populations has become increasingly apparent, with escalating cancer burdens and chronic disease. The challenges to recruitment of minorities in the United States are multiple including trust or lack thereof. Keys to successful recruitment are responding to community issues, its history, beliefs, and its social and economic pressures. The strategy we have used in many low-income, sometimes remote, communities is to recruit staff from the same community and train them in the required basic research methods. They are the first line of communication. After our arrival in the Texas Rio Grande Valley in 2001, we applied these principles learned over years of global research, to studies of chronic diseases. Beginning in 2004, we recruited and trained a team of local women who enrolled in a cohort of over five thousand Mexican Americans from randomly selected households. This cohort is being followed, and the team has remained, acquiring not only advanced skills (ultrasound, FibroScan, retinal photos, measures of cognition, etc.) but capacity to derive key health information. Currently, we are participating in multiple funded studies, including an NIH clinical trial, liver disease, obesity, and diabetes using multiomics aimed at developing precision medicine approaches to chronic disease prevention and treatment.

Low-cost, high-resolution imaging for detecting cervical precancer in medically-underserved areas of Texas.

OBJECTIVE: Cervical cancer rates in the United States have declined since the 1940's, however, cervical cancer incidence remains elevated in medically-underserved areas, especially in the Rio Grande Valley (RGV) along the Texas-Mexico border. High-resolution microendoscopy (HRME) is a low-cost, in vivo imaging technique that can identify high-grade precancerous cervical lesions (CIN2+) at the point-of-care. The goal of this study was to evaluate the performance of HRME in medically-underserved areas in Texas, comparing results to a tertiary academic medical center. METHODS: HRME was evaluated in five different outpatient clinical settings, two in Houston and three in the RGV, with medical providers of varying skill and training. Colposcopy, followed by HRME imaging, was performed on eligible women. The sensitivity and specificity of traditional colposcopy and colposcopy followed by HRME to detect CIN2+ were compared and HRME image quality was evaluated. RESULTS: 174 women (227 cervical sites) were included in the final analysis, with 12% (11% of cervical sites) diagnosed with CIN2+ on histopathology. On a per-site basis, a colposcopic impression of low-grade precancer or greater had a sensitivity of 84% and a specificity of 45% to detect CIN2+. While there was no significant difference in sensitivity (76%, p = 0.62), the specificity when using HRME was significantly higher than that of traditional colposcopy (56%, p = 0.01). There was no significant difference in HRME image quality between clinical sites (p = 0.77) or medical providers (p = 0.33). CONCLUSIONS: HRME imaging increased the specificity for detecting CIN2+ when compared to traditional colposcopy. HRME image quality remained consistent across different clinical settings.

The Precarious Health of Young Mexican American Men in South Texas, Cameron County Hispanic Cohort, 2004-2015.

INTRODUCTION: Hispanic men have higher rates of illness and death from various chronic conditions than do non-Hispanic men. We aimed to characterize the health of Mexican American men living on the US-Mexico border in South Texas and elucidate indications of chronic disease in young men. METHODS: We sampled all male participants from the Cameron County Hispanic Cohort, an ongoing population-based cohort of Mexican Americans in Brownsville, Texas. We calculated descriptive statistics and stratified the sample into 3 age groups to estimate the prevalence of sociodemographic, behavioral, and clinical factors by age group and evaluated differences between age groups. RESULTS: Obesity prevalence was approximately 50% across all age groups (P = .83). Diabetes prevalence was high overall (26.8%), and 16.9% (95% confidence interval [CI], 10.1%-23.8%) of men younger than 35 had diabetes. More than 70% of these young men had elevated liver enzymes, and mean values of aspartate aminotransferase were significantly higher in younger men (45.0 u/L; 95% CI, 39.5-50.6 u/L) than in both older age groups. Less than 20% of young men had any form of health insurance. Current smoking was higher in young men than in men in the other groups, and the rate was higher than the national prevalence of current smoking among Hispanic men. CONCLUSIONS: We suggest a need for obesity and diabetes prevention programs and smoking cessation programs for men in this region. Opportunities exist to expand current intervention programs and tailor them to better reach this vulnerable population of young Hispanic men. Elevated liver enzymes in men younger than 35 suggest a substantial burden of liver abnormalities, a finding that warrants further study.

Liver and Other Gastrointestinal Cancers Are Frequent in Mexican Americans.

BACKGROUND: Disease patterns in Mexican American health-disparity populations differ from larger US populations. AIMS: This study is aimed to determine frequency of gastrointestinal cancers in Mexican Americans. METHODS: We analyzed self-reported data from the Cameron County Hispanic Cohort where we find high rates of risk factors for cancer: obesity (48.5 %) and diabetes (30.7 %). Participants provided cancer histories about themselves and first- and second-degree relatives. Logistic regression models assessed risk factors. Frequencies of cancer sites were ranked and validated using concurrent age local cancer registry data. RESULTS: Among 9,249 individuals (participants and their relatives), there were 1,184 individuals with reports of cancer. Among cohort participants under 70 years of age, the most significant risk factor for all-cause cancers was diabetes (OR 3.57, 95 % CI 1.32, 9.62). Participants with metabolic syndrome were significantly more likely to report cancer in relatives [1.73 (95 % CI 1.26, 2.37]. Among cancers in fathers, liver cancer was ranked third, stomach fourth, colorectal sixth, and pancreas tenth. In mothers, stomach was third, liver fourth, colorectal seventh, and pancreas eleventh. The unusual prominence of these cancers in Mexican Americans, including liver cancer, was supported by age-adjusted incidence in local registry data. CONCLUSIONS: Gastrointestinal system cancers, particularly, liver cancer, in a Mexican American health disparity cohort and their relatives rank higher than in other ethnicities and are associated with high rates of diabetes and metabolic syndrome. Effective prevention of diabetes and low-tech, high-quality screening strategies for gastrointestinal cancers are needed in health disparity communities.

Undiagnosed Diabetes and Pre-Diabetes in Health Disparities.

Globally half of all diabetes mellitus is undiagnosed. We sought to determine the extent and characteristics of undiagnosed type 2 diabetes mellitus and pre-diabetes in Mexican Americans residing in the United States. This disadvantaged population with 50% lifetime risk of diabetes is a microcosm of the current pandemic. We accessed baseline data between 2004 and 2014 from 2,838 adults recruited to our Cameron County Hispanic Cohort (CCHC); a two-stage randomly selected 'Framingham-like' cohort of Mexican Americans on the US Mexico border with severe health disparities. We examined prevalence, risk factors and metabolic health in diagnosed and undiagnosed diabetes and pre-diabetes. Two thirds of this Mexican American population has diabetes or pre-diabetes. Diabetes prevalence was 28.0%, nearly half undiagnosed, and pre-diabetes 31.6%. Mean BMI among those with diabetes was 33.5 kg/m2 compared with 29.0 kg/m2 for those without diabetes. Significant risk factors were low income and educational levels. Most with diabetes had increased waist/hip ratio. Lack of insurance and access to health services played a decisive role in failure to have diabetes diagnosed. Participants with undiagnosed diabetes and pre-diabetes had similar measures of poor metabolic health similar but generally not as severe as those with diagnosed diabetes. More than 50% of a minority Mexican American population in South Texas has diabetes or pre-diabetes and is metabolically unhealthy. Only a third of diabetes cases were diagnosed. Sustained efforts are imperative to identify, diagnose and treat individuals in underserved communities.

Community-based assessment of surgical symptoms in a low-income urban population.

BACKGROUND: The global burden of surgical disease has not been well quantified, but is potentially immense. Given the enormity of the problem and the relative paucity of data, definition and monitoring of surgical burden of disease is an essential step in confronting the problem. This study aimed to estimate the prevalence of non-acute surgical disease symptoms in a low-income population. METHODS: The survey was conducted as part of the Indus Hospital Community Cohort in Karachi, Pakistan. A systematic random sampling design was used to enroll 667 households from March to August 2011. An unvalidated questionnaire intending to measure prevalence of surgical symptoms was administered to 780 participants. RESULTS: 761 participants completed the screening questionnaire, with 346 (45%) reporting one or more symptoms requiring surgical assessment (excluding those screened positive for symptoms of osteoarthritis), of which only 8.4% followed up on scheduled appointments at the referral hospital. A total of 126 past surgical procedures were recorded in 120 participants. CONCLUSION: There is a high prevalence of symptoms suggestive of surgical diseases in our urban catchment population with relatively convenient access to health facilities including a tertiary care hospital providing free of cost care. The perceived severity of symptoms, and a complex interaction of other factors, may play an important role in understanding health seeking behavior in our population. Developing a context-specific validated tool to correctly identify surgical symptoms disease in the community with appropriate referral for early management is essential to identify and therefore reduce the burden of surgical diseases within the community. This must happen hand in hand with further studies to understand the barriers to seeking timely health care.

Socio-ecological influences on health-care access and navigation among persons of Mexican descent living on the U.S./Mexico border.

The study reported here examines factors influencing decision-making concerning health care access and navigation among persons of Mexican origin living along the U.S./Mexico border. Specifically, the study examined how persons with limited financial resources accessed these two systems. Seven focus groups were held with 52 low income Mexican American people aged 18-65 years. Transcripts were analyzed to identify themes in Atlasti 5.0 software and the theory used included a socio-ecological framework and complemented by constructed from the Social Cognitive Theory. We found that in addition to a lack of insurance and financial resources to pay for health care; fear, embarrassment and denial associated with a diagnosis of illness; poor medical personnel interactions, and desire for quality but streamlined health care also influenced decision making. This theory-based study raises important issues if health care is to improve the health and welfare of disadvantaged populations and points to the need for greater focus on medical homes and prevention and early intervention approaches.

The burden of non-communicable disease in transition communities in an Asian megacity: baseline findings from a cohort study in Karachi, Pakistan.

BACKGROUND: The demographic transition in South Asia coupled with unplanned urbanization and lifestyle changes are increasing the burden of non-communicable disease (NCD) where infectious diseases are still highly prevalent. The true magnitude and impact of this double burden of disease, although predicted to be immense, is largely unknown due to the absence of recent, population-based longitudinal data. The present study was designed as a unique 'Framingham-like' Pakistan cohort with the objective of measuring the prevalence and risk factors for hypertension, obesity, diabetes, coronary artery disease and hepatitis B and C infection in a multi-ethnic, middle to low income population of Karachi, Pakistan. METHODS: We selected two administrative areas from a private charitable hospital's catchment population for enrolment of a random selection of cohort households in Karachi, Pakistan. A baseline survey measured the prevalence and risk factors for hypertension, obesity, diabetes, coronary artery disease and hepatitis B and C infection. RESULTS: Six hundred and sixty-seven households were enrolled between March 2010 and August 2011. A majority of households lived in permanent structures (85%) with access to basic utilities (77%) and sanitation facilities (98%) but limited access to clean drinking water (68%). Households had high ownership of communication technologies in the form of cable television (69%) and mobile phones (83%). Risk factors for NCD, such as tobacco use (45%), overweight (20%), abdominal obesity (53%), hypertension (18%), diabetes (8%) and pre-diabetes (40%) were high. At the same time, infectious diseases such as hepatitis B (24%) and hepatitis C (8%) were prevalent in this population. CONCLUSION: Our findings highlight the need to monitor risk factors and disease trends through longitudinal research in high-burden transition communities in the context of rapid urbanization and changing lifestyles. They also demonstrate the urgency of public health intervention programs tailored for these transition communities.

Missed opportunities for diagnosis and treatment of diabetes, hypertension, and hypercholesterolemia in a Mexican American population, Cameron County Hispanic Cohort, 2003-2008.

INTRODUCTION: Diabetes, hypertension, and hypercholesterolemia are common chronic diseases among Hispanics, a group projected to comprise 30% of the US population by 2050. Mexican Americans are the largest ethnically distinct subgroup among Hispanics. We assessed the prevalence of and risk factors for undiagnosed and untreated diabetes, hypertension, and hypercholesterolemia among Mexican Americans in Cameron County, Texas. METHODS: We analyzed cross-sectional baseline data collected from 2003 to 2008 in the Cameron County Hispanic Cohort, a randomly selected, community-recruited cohort of 2,000 Mexican American adults aged 18 or older, to assess prevalence of diabetes, hypertension, and hypercholesterolemia; to assess the extent to which these diseases had been previously diagnosed based on self-report; and to determine whether participants who self-reported having these diseases were receiving treatment. We also assessed social and economic factors associated with prevalence, diagnosis, and treatment. RESULTS: Approximately 70% of participants had 1 or more of the 3 chronic diseases studied. Of these, at least half had had 1 of these 3 diagnosed, and at least half of those who had had a disease diagnosed were not being treated. Having insurance coverage was positively associated with having the 3 diseases diagnosed and treated, as were higher income and education level. CONCLUSIONS: Although having insurance coverage is associated with receiving treatment, important social and cultural barriers remain. Failure to provide widespread preventive medicine at the primary care level will have costly consequences.

High prevalence of subclinical atherosclerosis by carotid ultrasound among Mexican Americans: discordance with 10-year risk assessment using the Framingham risk score.

BACKGROUND: Framingham risk scores (FRS) were validated in a mostly Caucasian population. Evaluation of subclinical atherosclerosis by carotid ultrasound may improve ascertainment of risk in nonwhite populations. This study aimed to evaluate carotid intima-media thickness (cIMT) and carotid plaquing among Mexican Americans, and to correlate these markers with coronary risk factors and the FRS. METHODS/RESULTS: Participants (n = 141) were drawn from the Cameron County Hispanic Cohort. Carotid artery ultrasound was performed and cIMT measured. Carotid plaque was defined as areas of thickening >50% of the thickness of the surrounding walls. Mean age was 53.1 ± 11.7 years (73.8% female). Most were overweight or obese (88.7%) and more than half (53.2%) had the metabolic syndrome. One third (34.8%) had abnormal carotid ultrasound findings (either cIMT ≥75th percentile for gender and age or presence of plaque). Among those with abnormal carotid ultrasound, the majority were classified as being at low 10-year risk for cardiovascular events. Carotid ultrasound reclassified nearly a third of the cohort as being at high risk. This discordance between 10-year FRS and carotid ultrasound was noted whether risk was assessed for hard coronary events or global risk. Concordance between FRS and carotid ultrasound findings was best when long-term (30-year) risk was assessed and no subject with an abnormal carotid ultrasound was categorized as low risk by the 30-year FRS algorithm. CONCLUSIONS: Integration of carotid ultrasound findings to coronary risk assessments and use of longer term prediction models may provide better risk assessment in this minority population, with earlier initiation of appropriate therapies.

Ancestry informative marker set for han chinese population.

The population of Han Chinese is ∼1.226 billion people. Genetic heterogeneity between northern Han Chinese (N-Han) and southern Han Chinese (S-Han) has been demonstrated by recent genome-wide studies. As an initial step toward health disparities and personalized medicine in Chinese population, this study developed a set of ancestry informative markers (AIM) for Han Chinese population.

ELECTROCARDIOGRAPHIC ABNORMALITIES AMONG MEXICAN AMERICANS: CORRELATIONS WITH DIABETES, OBESITY, AND THE METABOLIC SYNDROME.

BACKGROUND: Resting ischemic electrocardiographic abnormalities have been associated with cardiovascular mortality. Simple markers of abnormal autonomic tone have also been associated with diabetes, obesity, and the metabolic syndrome in some populations. Data on these electrocardiographic abnormalities and correlations with coronary risk factors are lacking among Mexican Americans wherein these conditions are prevalent. OBJECTIVE: This study aimed to evaluate the prevalent resting electrocardiographic abnormalities among community-dwelling Mexican Americans, and correlate these findings with coronary risk factors, particularly diabetes, obesity, and the metabolic syndrome. METHODS: Study subjects (n=1280) were drawn from the Cameron County Hispanic Cohort comprised of community-dwelling Mexican Americans living in Brownsville, Texas at the United States-Mexico border. Ischemic electrocardiographic abnormalities were defined as presence of ST/T wave abnormalities suggestive of ischemia, abnormal Q waves, and left bundle branch block. Parameters that reflect autonomic tone, such as heart rate-corrected QT interval and resting heart rate, were also measured. RESULTS: Ischemic electrocardiographic abnormalities were more prevalent among older persons and those with hypertension, diabetes, obesity, and the metabolic syndrome. Subjects in the highest quartiles of QTc interval and resting heart rate were also more likely to be diabetic, hypertensive, obese, or have the metabolic syndrome. CONCLUSIONS: Among Mexican Americans, persons with diabetes, obesity, and the metabolic syndrome were more likely to have ischemic electrocardiographic abnormalities, longer QTc intervals, and higher resting heart rates. A resting electrocardiogram can play a complementary role in the comprehensive evaluation of cardiovascular risk in this minority population.

Polycyclic aromatic hydrocarbons in maternal and umbilical cord blood from pregnant Hispanic women living in Brownsville, Texas.

Venous blood was drawn from 35 pregnant Hispanic women living in Brownsville, Texas, and matched cord blood was collected at birth. Gas chromatography/mass spectrometry was used to measure concentrations of 55 individual PAHs or groups of PAHs. Results indicate that these women and their fetuses were regularly exposed to multiple PAHs at comparatively low concentrations, with levels in cord blood generally exceeding levels in paired maternal blood. While the possibility of related adverse effects on the fetus is uncertain, these exposures in combination with socioeconomically-disadvantaged and environmentally-challenging living conditions raise legitimate public health concerns.

Cross-sectional assessment reveals high diabetes prevalence among newly-diagnosed tuberculosis cases.

OBJECTIVE: To estimate the contribution of clinically-confirmed diabetes mellitus to tuberculosis (TB) rates in communities where both diseases are prevalent as a way to identify opportunities for TB prevention among diabetic patients. METHODS: This is a prospective study in which TB patients ≥ 20 years old at TB clinics in the Texas-Mexico border were tested for diabetes. The risk of tuberculosis attributable to diabetes was estimated from statistics for the corresponding adult population. FINDINGS: The prevalence of diabetes among TB patients was 39% in Texas and 36% in Mexico. Diabetes contributed 25% of the TB cases studied, whereas human immunodeficiency virus (HIV) infection contributed 5% or fewer. Among TB patients, fewer Mexicans than Texans were aware that they had diabetes before this study (4% and 19%, respectively). Men were also less frequently aware than women that they had diabetes (P = 0.03). Patients who knew that they had diabetes before the study had an 8-year history of the disease, on average, before being diagnosed with TB. CONCLUSION: Patients with diabetes are at higher risk of contracting TB than non-diabetic patients. Integrating TB and diabetes control programmes worldwide would facilitate TB prevention among diabetes patients and increase the number of diabetics who learn of their condition, particularly among males. Such a strategy would lead to earlier case detection and improve the management of both TB and diabetes.

The missing men: high risk of disease in men of Mexican origin.

The present study sought to determine gender- and age-specific prevalences of chronic diseases in an urban Mexican American border community. The Cameron County Hispanic Cohort (CCHC; n = 2,000) was selected using a multistaged cluster design. Sociodemographics, anthropometric measures, and blood samples were collected on each participant. More women were obese (55.1%) than men (44.8%). Men had significantly higher rates of diabetes (20.4% for men vs. 15.8% for women, p < .05) and undiagnosed diabetes (6.2% for men vs. 2.4% for women, p < .01); the prevalence of diabetes rose steeply between the ages of 40 and 49 years. Men were significantly more likely to have serum cholesterol levels of 200 mg/dL and elevated low-density lipoprotein levels (22.6% vs. 26.1%, p < .01). Mexican American males in the U.S./Mexico border region have a high prevalence of obesity in younger men and higher overall rates of diabetes, including undiagnosed diabetes, and significantly higher serum cholesterol levels than women.

Socioeconomic status and prevalence of obesity and diabetes in a Mexican American community, Cameron County, Texas, 2004-2007.

INTRODUCTION: Mexican Americans are at increased risk for obesity and diabetes. We established a cohort on the United States-Mexico border to determine the prevalence of obesity and diabetes in this Mexican American population and to see whether minor economic advantages had any effect on health. METHODS: We randomly selected and extensively documented 810 people aged 35 to 64 years. Weighted data were analyzed to establish prevalence of obesity and diabetes and other markers of poor health such as elevated glycated hemoglobin levels. RESULTS: Rates of obesity (body mass index > or = 30 kg/m(2)) were 57% in the first (lower) of 4 socioeconomic strata by income and were 55.5% in the third (higher). People in the higher socioeconomic stratum were significantly less likely to have undiagnosed diabetes (2% vs 9%). Among people aged 55 to 64 years, rates of diabetes were significantly higher among those in the lower socioeconomic stratum than among those in the higher stratum. Rates of undiagnosed diabetes had similar differences. Approximately three-fourths of the respondents reported having no health insurance, and we found no difference between people in different socioeconomic strata. CONCLUSION: Rates of obesity and diabetes in this border community are among the highest in the United States. Belonging to the lower socioeconomic stratum significantly increased the likelihood of having undiagnosed diabetes and, in patients too young to be eligible for Medicare, the overall risk of developing diabetes. Modest improvement in income has a beneficial effect on health in this racial/ethnic minority community.