A high burden of diabetes and ankle brachial index abnormalities exists in Mexican Americans in South Texas

Ethnic differences exist in the United States in the interrelated problems of diabetes (DM), peripheral arterial disease (PAD), and leg amputations. The purpose of this study was to determine the prevalence and risk factor associations for subclinical PAD in a population sample of Mexican Americans using the ankle brachial (ABI) index. The ABI-High (higher of the two ankle pressures/highest brachial pressure) and ABI-Low (lower of the two ankle pressures/highest brachial pressure) were calculated to define PAD. Toe brachial index (TBI) was also calculated. 746 participants were included with an age of 53.4 ± 0.9 years, 28.3 % had diabetes mellitus (DM), 12.6 % were smokers, and 51.2 % had hypertension (HTN). Using ABI-High ≤ 0.9, the prevalence of PAD was 2.7 %. This rose to 12.7 % when an ABI-Low ≤ 0.9 was used; 4.0 % of the population had an ABI-High > 1.4. The prevalence of TBI < 0.7 was 3.9 %. DM was a significant risk factor for ABI-High ≤ 0.9 and ABI-High > 1.4, and TBI < 0.7. Increased age, HTN, smoking was associated with ABI-High ≤ 0.9, while being male was associated with ABI-High > 1.4. Increased age, smoking, and lower education were all associated with abnormal TBI. Despite relatively younger mean age than other studied Hispanic cohorts, the present population has a high burden of ABI abnormalities. DM was a consistent risk factor for PAD. These abnormalities indicate an important underlying substrate of vascular and metabolic disease that may predispose this population to the development of symptomatic PAD and incident amputations.

A prognostic molecular signature of hepatic steatosis is spatially heterogeneous and dynamic in human liver

Metabolic dysfunction-associated steatotic liver disease (MASLD) prevalence is increasing in parallel with an obesity pandemic, calling for novel strategies for prevention and treatment. We defined a circulating proteome of human MASLD across ≈7000 proteins in ≈5000 individuals from diverse, at-risk populations across the metabolic health spectrum, demonstrating reproducible diagnostic performance and specifying both known and novel metabolic pathways relevant to MASLD (central carbon and amino acid metabolism, hepatocyte regeneration, inflammation, fibrosis, insulin sensitivity). A parsimonious proteomic signature of MASLD was associated with a protection from MASLD and its related multi-system metabolic consequences in >26000 free-living individuals, with an additive effect to polygenic risk. The MASLD proteome was encoded by genes that demonstrated transcriptional enrichment in liver, with spatial transcriptional activity in areas of steatosis in human liver biopsy and dynamicity for select targets in human liver across stages of steatosis. We replicated several top relations from proteomics and spatial tissue transcriptomics in a humanized "liver-on-a-chip" model of MASLD, highlighting the power of a full translational approach to discovery in MASLD. Collectively, these results underscore utility of blood-based proteomics as a dynamic "liquid biopsy" of human liver relevant to clinical biomarker and mechanistic applications.

A Comprehensive Program to Improve Treatment of Precancerous Cervical Lesions in the Rio Grande Valley of Texas

OBJECTIVE

To assess the impact of a multicomponent intervention in women with cervical dysplasia who were treated with loop electrosurgical excision procedure (LEEP), as well as the time between colposcopy and treatment.

DESIGN

Retrospective cohort study.

INTERVENTION

Clinic participation in a multicomponent cervical cancer prevention program that included community outreach, patient in-reach, and navigation, as well as provider capacity building with in-person training and ongoing telementoring through Project ECHO.

MAIN OUTCOME MEASURES

Medical records were reviewed to evaluate women with cervical dysplasia undergoing treatment with LEEP within 90 days of colposcopy, as well as time between colposcopy and treatment. Baseline data from year 1 were compared with each subsequent year of implementation. Additional variables examined included patient's age, history of abnormal screening results, and percentage of families living below poverty line based on county of residence, parity, and clinic site. We performed logistic regression and multiple linear regression analyses to assess the programmatic impact in the outcomes of interest by year of program implementation.

RESULTS

A total of 290 women were included in the study. The proportion of women undergoing treatment within 90 days of colposcopy increased from 76.2% at baseline to 91.3% in year 3 and 92.9% in year 4 of program implementation. The odds of undergoing treatment within 90 days were 5.11 times higher in year 4 of program implementation than at baseline. The mean time between colposcopy and LEEP decreased from 62 days at baseline to 45 days by year 4 of program implementation.

CONCLUSIONS

Implementation of our multicomponent cervical cancer prevention program increased the proportion of women undergoing LEEP within 90 days of colposcopy and decreased the time between colposcopy and LEEP. This program has the potential to support cervical cancer prevention efforts and could be implemented in other low-resource settings.

Addressing cervical cancer disparities in Texas: Expansion of a community-based prevention initiative for medically underserved populations

Although cervical cancer is preventable, significant disparities exist in access to screening and prevention services. In medically underserved areas (MUAs) of Texas, these rates are 55% higher compared to the remainder of the US. In 2019, we expanded a multicomponent, comprehensive program to improve cervical cancer prevention in partnership with 13 clinics and mobile vans in MUAs of Texas. Our multicomponent intervention program consists of community education and patient navigation coupled with a training/mentoring program for local medical providers to perform diagnostic procedures and treatment for patients with abnormal screening results. Hands-on training courses to learn these skills are coupled with biweekly telementoring conferences using Project ECHO® (Extension for Community Healthcare Outcomes). This program was implemented in 2015 and expanded to other MUAs in Texas in 2019. From March 2019 to August 2022, 75,842 individuals were educated about cervical cancer screening and HPV vaccination. A total of 44,781 women underwent screening for cervical cancer, and 2,216 underwent colposcopy and 264 underwent LEEP. High-grade cervical dysplasia was diagnosed in 658 individuals and invasive cervical cancer in 33 individuals. We trained 22 providers to perform colposcopy and/or LEEP. In addition, 78 Project ECHO telementoring sessions were held with an average of 42 attendees per session, with 72 individual patient cases discussed. Our comprehensive community-based prevention initiative for medically underserved populations has led to a significant number of individuals undergoing cervical cancer screening in MUAs, as well as improved access to colposcopy and LEEP services.

Addressing high cervical cancer rates in the Rio Grande Valley along the Texas-Mexico border: a community-based initiative focused on education, patient navigation, and medical provider training/telementoring

AIMS

Cervical cancer incidence and mortality rates are approximately 55% higher in the Rio Grande Valley (RGV) along the Texas-Mexico border compared with the average rates in the US. Our aim was to improve cervical cancer prevention efforts in the RGV through a comprehensive multilevel intervention initiative focused on community education, patient navigation, and training of local providers.

METHODS

We initiated a program in the RGV which consisted of (1) community education, (2) patient navigation, and (3) a training/mentoring program for local medical providers including hands-on training courses coupled with telementoring using Project ECHO® (Extension for Community Health Outcomes). We assessed the number of women undergoing cervical cancer screening, diagnosis, and treatment at three participating clinics caring for underserved women in the region.

RESULTS

From November 2014 to October 2018, 14,846 women underwent cervical cancer screening. A total of 2030 (13.7%) women underwent colposcopy for abnormal results (179% increase over baseline) and 453 women underwent loop electrosurgical excision procedures (LEEPs) for treatment of cervical dysplasia. Invasive cancer was diagnosed in 39 women who were navigated to a gynecologic oncologist for treatment. Seven local medical providers were trained to perform colposcopy and/or LEEP. Project ECHO telementoring videoconferences were held every 2 weeks for a total 101 sessions with an average of 22 participants per session and a total of 180 patient cases presented and discussed.

CONCLUSIONS

Our program led to a large number of women undergoing diagnosis and treatment of cervical dysplasia in the RGV. If sustained, we anticipate these efforts will decrease cervical cancer rates in the region. The program is currently being expanded to additional underserved areas of Texas and globally to low- and middle-income countries.

A Novel Bayesian Spatial-Temporal Approach to Quantify SARS-CoV-2 Testing Disparities for Small Area Estimation

Objectives. To propose a novel Bayesian spatial-temporal approach to identify and quantify severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing disparities for small area estimation. Methods. In step 1, we used a Bayesian inseparable space-time model framework to estimate the testing positivity rate (TPR) at geographically granular areas of the census block groups (CBGs). In step 2, we adopted a rank-based approach to compare the estimated TPR and the testing rate to identify areas with testing deficiency and quantify the number of needed tests. We used weekly SARS-CoV-2 infection and testing surveillance data from Cameron County, Texas, between March 2020 and February 2022 to demonstrate the usefulness of our proposed approach. Results. We identified the CBGs that had experienced substantial testing deficiency, quantified the number of tests that should have been conducted in these areas, and evaluated the short- and long-term testing disparities. Conclusions. Our proposed analytical framework offers policymakers and public health practitioners a tool for understanding SARS-CoV-2 testing disparities in geographically small communities. It could also aid COVID-19 response planning and inform intervention programs to improve goal setting and strategy implementation in SARS-CoV-2 testing uptake. (Am J Public Health. 2023;113(1):40-48. https://doi.org/10.2105/AJPH.2022.307127).

Correction: Census Tract Patterns and Contextual Social Determinants of Health Associated With COVID-19 in a Hispanic Population From South Texas: A Spatiotemporal Perspective

[This corrects the article DOI: 10.2196/29205.].

Census Tract Patterns and Contextual Social Determinants of Health Associated With COVID-19 in a Hispanic Population From South Texas: A Spatiotemporal Perspective

BACKGROUND

Previous studies have shown that various social determinants of health (SDOH) may have contributed to the disparities in COVID-19 incidence and mortality among minorities and underserved populations at the county or zip code level.

OBJECTIVE

This analysis was carried out at a granular spatial resolution of census tracts to explore the spatial patterns and contextual SDOH associated with COVID-19 incidence from a Hispanic population mostly consisting of a Mexican American population living in Cameron County, Texas on the border of the United States and Mexico. We performed age-stratified analysis to identify different contributing SDOH and quantify their effects by age groups.

METHODS

We included all reported COVID-19-positive cases confirmed by reverse transcription-polymerase chain reaction testing between March 18 (first case reported) and December 16, 2020, in Cameron County, Texas. Confirmed COVID-19 cases were aggregated to weekly counts by census tracts. We adopted a Bayesian spatiotemporal negative binomial model to investigate the COVID-19 incidence rate in relation to census tract demographics and SDOH obtained from the American Community Survey. Moreover, we investigated the impact of local mitigation policy on COVID-19 by creating the binary variable "shelter-in-place." The analysis was performed on all COVID-19-confirmed cases and age-stratified subgroups.

RESULTS

Our analysis revealed that the relative incidence risk (RR) of COVID-19 was higher among census tracts with a higher percentage of single-parent households (RR=1.016, 95% posterior credible intervals [CIs] 1.005, 1.027) and a higher percentage of the population with limited English proficiency (RR=1.015, 95% CI 1.003, 1.028). Lower RR was associated with lower income (RR=0.972, 95% CI 0.953, 0.993) and the percentage of the population younger than 18 years (RR=0.976, 95% CI 0.959, 0.993). The most significant association was related to the "shelter-in-place" variable, where the incidence risk of COVID-19 was reduced by over 50%, comparing the time periods when the policy was present versus absent (RR=0.506, 95% CI 0.454, 0.563). Moreover, age-stratified analyses identified different significant contributing factors and a varying magnitude of the "shelter-in-place" effect.

CONCLUSIONS

In our study, SDOH including social environment and local emergency measures were identified in relation to COVID-19 incidence risk at the census tract level in a highly disadvantaged population with limited health care access and a high prevalence of chronic conditions. Results from our analysis provide key knowledge to design efficient testing strategies and assist local public health departments in COVID-19 control, mitigation, and implementation of vaccine strategies.

A Lack of Decline in Major Nontraumatic Amputations in Texas: Contemporary Trends, Risk Factor Associations, and Impact of Revascularization

OBJECTIVE

Nontraumatic major lower extremity amputations (LEAs) have been reported to be declining nationally; however, trends in Texas have been less well described. We evaluated demographic and clinical risk factors and revascularization associations for LEAs by using inpatient hospital discharge data in Texas from 2005 to 2014.

RESEARCH DESIGN AND METHODS

Inpatient hospital discharge data were obtained from the Texas Center for Health Statistics. Multivariate logistic regression analyses were performed to evaluate clinical, ethnic, and socioeconomic risk factors associated with LEA. The impact of revascularization (surgical and/or endovascular) on LEA was analyzed.

RESULTS

Between 2005 and 2014, of 19,939,716 admissions, 46,627 were for nontraumatic major LEAs. Over time, LEAs were constant, and revascularization rates during index admission declined. The majority of LEAs occurred in males and in individuals aged 60-79 years. Risk factors associated with LEA included diabetes, peripheral arterial disease, chronic kidney disease, and male sex (P < 0.001). Insurance status, hyperlipidemia, coronary artery disease, and stroke/transient ischemic attack were associated with lower odds of amputation (P < 0.001). Hispanic (odds ratio [OR] 1.51 [95% CI 1.48, 1.55], P < 0.001) and black (OR 1.97 [95% CI 1.92, 2.02], P < 0.001) ethnicities were associated with a higher risk for amputation when compared with non-Hispanic whites. Revascularization, either surgical or endovascular (OR 0.52 [95% CI 0.5, 0.54], P < 0.001), was also associated with lower odds for amputation.

CONCLUSIONS

Amputation rates in Texas have remained constant, whereas revascularization rates are declining. A higher risk for LEA was seen in minorities, including Hispanic ethnicity, which is the fastest growing demographic in Texas. Revascularization and having insurance were associated with lower odds for amputation.

MON-117 The Association of Adipocytokine Concentrations with Obesity and Metabolic Health in a Mexican-American Border Populations

Adipocytokines are hormones released from adipose cells. Their functions range from regulating hunger to regulating the metabolic effects of insulin. What role these hormones play in metabolic health and diabetes have not been studied in the Hispanic population. The present study examines associations between leptin, resistin and adiponectin levels in obesity and metabolic health in a Mexican-American border population, with a specific focus on leptin. We hypothesized that 1) Obese subjects display higher leptin levels, regardless of metabolic health and 2) Metabolically healthy subjects display higher leptin levels, regardless of obesity status. To study the association of plasma adipocytokines with weight and metabolic health, we performed a cross-sectional, retrospective study using patient data collected by the Cameron County Hispanic Cohort in Brownsville, Texas. Obesity is BMI ≥ 30 kg/m2. We determined metabolic health status by assessing the presence of the following four criteria: elevated blood pressure (SBP ≥ 130 mmHg and/or DBP ≥ 85 mmHg), elevated triglycerides ≥ 150 mg/dL, low HDL cholesterol (males < 40 mg/dL; females < 50 mg/dL), and elevated fasting glucose ≥ 100 mg/dL (or use of hypoglycemic medications). The presence of < 2 of these criteria defined a subject as “metabolically healthy”. We categorized the patients into four groups: metabolically healthy normal weight (MHNW, n = 245), metabolically healthy obese (MHO, n = 107), metabolically unhealthy normal weight (MUHNW, n = 97), and metabolically unhealthy obese (MUHO, n = 187). We excluded persons < 18 years of age, current smokers, subjects with major cardiovascular events or active malignancy, and subjects using confounding medications. We conducted comparisons of log-transformed adipocytokine concentrations data between the groups using multivariable linear regression after adjusting for sex, age, BMI and hypertension. Leptin was significantly higher in MHO compared to MHNW (p < 0.0001) and MUHNW (p = 0.02), and significantly higher in MUHO compared to MUHNW (p = 0.01) and MHNW (<0.0001). Resistin was higher in MUHNW (p = 0.01) and MUHO (p = 0.03) compared to MHO. Adiponectin levels were lower in MUHO compared to MHNW (p = 0.002). In this Mexican-American population, the results showed that leptin levels were influenced by obesity and not by overall metabolic health status. These findings confirm Hypothesis number 1 and run contrary to Hypothesis number 2. Additionally, resistin levels were significantly higher in metabolically unhealthy patients irrespective of BMI, while both metabolic health and normal weight favored higher adiponectin. Obesity showed a robust association with leptin, metabolic health displayed a strong association with resistin, and both factors influenced adiponectin levels in this population.

Perspectives on cervical cancer screening and prevention: challenges faced by providers and patients along the Texas–Mexico border

Background:

The Rio Grande Valley (RGV) and Laredo regions located along the Texas–Mexico border consist of seven counties with a population of approximately 1.5 million people and a high uninsured rate (33.5%). Cervical cancer mortality in these border counties is approximately 30% higher than the rest of Texas. The RGV and Laredo areas were studied to better understand the state of access to cervical cancer prevention services along the Texas–Mexico border.

Methods:

Data on the population served and the services provided were analyzed to determine the gap between cervical cancer screenings recommended versus those received. Through interviews, we gathered the perspectives of 16 local stakeholders regarding cervical cancer screening for underserved individuals in the region.

Findings:

It is estimated that 69,139 uninsured women aged 21–64 years in the RGV/Laredo per year are recommended to undergo cervical cancer screening with Papanicolaou (Pap) and/or human papillomavirus (HPV) testing, but only 8941 (12.9%) Pap tests are being performed by the Federally Qualified Health Center (FQHC) serving uninsured women in these regions. Systemic barriers identified include insufficient provider clinical capacity, the high cost of healthcare, and uncertainty about government funding sources. Patient barriers identified include inadequate knowledge on navigating the local healthcare system, low health literacy, lack of money and childcare, an inability to miss work, limited transportation, and fear of deportation.

Conclusion:

Decreasing the disparity between cervical cancer screening services provided and those recommended requires addressing the barriers, identified by local experts, which prevent uninsured women from accessing care. These challenges are being addressed through ongoing programs and collaborations.

Trabecular Bone Score Is a Valuable Addition to Bone Mineral Density for Bone Quality Assessment in Older Mexican American Women With Type 2 Diabetes

Altered bone quality due to the underlying metabolic changes of type 2 diabetes (T2D) has been hypothesized to affect bone strength, leading to increased fracture risk in patients with T2D. Lumbar spine trabecular bone score (LS-TBS), an indirect measure of trabecular microarchitecture, provides information on bone quality and has been associated with T2D. However, trabecular bone score (TBS) is also affected by demographic patterns and body size, and is expected to be different in people from various ethnic or racial backgrounds. Therefore, it is important to understand associations between T2D and TBS for each ethnic or racial group separately. Although the relationship between TBS and age has been reported to be similar between non-Hispanic Caucasians and Mexican Americans (MAs), data on associations of LS-TBS with T2D in older MAs are lacking. Here, we report associations between TBS and T2D in 149 older MA men and women. Participants are part of a cohort known as the Cameron County Hispanic Cohort in Texas who have high prevalence of obesity and poor glycemic control. Bone mineral density was not altered for MA women with T2D, but was significantly higher in MA men with T2D compared with MA men without diabetes. Low LS-TBS was associated with T2D in women in our study. Although low TBS was associated with older age in men, TBS did not show any significant association with T2D for men. These results are similar to those found in other studies of non-Hispanic whites with diabetes. LS-TBS may add value in diagnosing poor bone quality in older MA women with T2D regardless of bone mineral density scoring.

The association between insulin resistance, metabolic variables, and depressive symptoms in Mexican-American elderly: A population-based study

OBJECTIVE

Depressive symptoms are common among older adults with obesity and diabetes. Nonetheless, the mechanisms for this association are not clear but may involve changes in the insulin cascade signaling. We aimed to investigate the association, and potential mediators, between obesity, insulin resistance, and depressive symptoms among older adults from a homogenous cohort of Mexican-Americans.

METHODS

We included a total of 500 Mexican-American older adults assessed in the Cameron County Health Study. We evaluated depressive symptoms using the Center for Epidemiologic Survey Depression Scale (CES-D). Central obesity was defined by waist circumference. Insulin resistance was evaluated by the HOMA-IR index. We estimated the association between obesity, insulin resistance, and depressive symptoms by carrying out univariate and multivariate regression analyses.

RESULTS

In unadjusted regression analysis, HOMA-IR (unstandardized β = 0.31 ± 0.12, P = 0.007), waist circumference (unstandardized β = 0.066 ± 0.0.028, P = 0.017), and Hb1Ac levels (unstandardized β = 0.52 ± 0.24, P = 0.03) were significantly associated with CES-D scores. The association of HOMA-IR and CES-D remained statistically significant after controlling for socio-demographic and clinical variables in multivariate analysis (unstandardized β = 0.28 ± 0.11, P = 0.01).

CONCLUSION

Our results suggest that depressive symptoms are associated with insulin resistance in older Mexican-American adults. In addition, poorer glucose control and obesity are important mediators of this relationship. Additional studies are needed to evaluate whether interventions that increase insulin sensitivity can also reduce depressive symptoms in this population.

One Health Interactions of Chagas Disease Vectors, Canid Hosts, and Human Residents along the Texas-Mexico Border

BACKGROUND

Chagas disease (Trypanosoma cruzi infection) is the leading cause of non-ischemic dilated cardiomyopathy in Latin America. Texas, particularly the southern region, has compounding factors that could contribute to T. cruzi transmission; however, epidemiologic studies are lacking. The aim of this study was to ascertain the prevalence of T. cruzi in three different mammalian species (coyotes, stray domestic dogs, and humans) and vectors (Triatoma species) to understand the burden of Chagas disease among sylvatic, peridomestic, and domestic cycles.

METHODOLOGY/PRINCIPAL FINDINGS

To determine prevalence of infection, we tested sera from coyotes, stray domestic dogs housed in public shelters, and residents participating in related research studies and found 8%, 3.8%, and 0.36% positive for T. cruzi, respectively. PCR was used to determine the prevalence of T. cruzi DNA in vectors collected in peridomestic locations in the region, with 56.5% testing positive for the parasite, further confirming risk of transmission in the region.

CONCLUSIONS/SIGNIFICANCE

Our findings contribute to the growing body of evidence for autochthonous Chagas disease transmission in south Texas. Considering this region has a population of 1.3 million, and up to 30% of T. cruzi infected individuals developing severe cardiac disease, it is imperative that we identify high risk groups for surveillance and treatment purposes.

Cardiovascular disease risk among the Mexican American population in the Texas-Mexico border region, by age and length of residence in United States

Introduction

Although the relationship between health behaviors and outcomes such as smoking and obesity with longer residence in the United States among Mexican American immigrants is established, the relationship between length of residency in the United States and risk for cardiovascular disease (CVD) is not fully understood. The objective of this study was to determine the relationship between immigrant status, length of residence in the United States, age, and CVD markers in a sample of Mexican American adults living in Brownsville, Texas.

Methods

We categorized participants in the Cameron County Hispanic Cohort study as immigrants in the United States for 10 years or less, immigrants in the United States for more than 10 years, or born in the United States. We conducted logistic and ordinary least squares regression for self-reported chronic conditions and CVD biomarkers.

Results

We found bivariate differences in the prevalence of self-reported conditions and 1 CVD biomarker (low-density lipoprotein cholesterol) by length of residence in the middle (41–64 y) and younger (18–40 y) age groups. After adjusting for covariates, the following varied significantly by immigrant status: stroke and high cholesterol (self-reported conditions) and diastolic blood pressure, systolic blood pressure, total cholesterol, and low-density lipoprotein cholesterol (CVD biomarkers).

Conclusion

The association between immigrant status, length of residence in the United States, and CVD markers varied. The effect of length of residence in the United States or immigrant status may depend on age and may be most influential in middle or older age.

Rapid research response to the 2009 A(H1N1)pdm09 influenza pandemic (Revised)

Background

When novel influenza viruses cause human infections, it is critical to characterize the illnesses, viruses, and immune responses to infection in order to develop diagnostics, treatments, and vaccines. The objective of the study was to collect samples from patients with suspected or confirmed A(H1N1)pdm09 infections that could be made available to the scientific community. Respiratory secretions, sera and peripheral blood mononuclear cells (PBMCs) were collected sequentially (when possible) from patients presenting with suspected or previously confirmed A(H1N1)pdm09 infections. Clinical manifestations and illness outcomes were assessed. Respiratory secretions were tested for the presence of A(H1N1)pdm09 virus by means of isolation in tissue culture and real time RT-PCR. Sera were tested for the presence and level of HAI and neutralizing antibodies against the A(H1N1)pdm09 virus.

Findings and conclusions

Thirty patients with confirmed A(H1N1)pdm09 infection were enrolled at Baylor College of Medicine (BCM). Clinical manifestations of illness were consistent with typical influenza. Twenty-eight of 30 had virological confirmation of illness; all recovered fully. Most patients had serum antibody responses or high levels of antibody in convalescent samples. Virus-positive samples were sent to J. Craig Venter Institute for sequencing and sequences were deposited in GenBank. Large volumes of sera collected from 2 convalescent adults were used to standardize antibody assays; aliquots of these sera are available from the repository. Aliquots of serum, PBMCs and stool collected from BCM subjects and subjects enrolled at other study sites are available for use by the scientific community, upon request.

Using the Framingham Risk Score to evaluate immigrant effect on cardiovascular disease risk in Mexican Americans

BACKGROUND

This study uses the Framingham Risk Score (FRS) for 10-year cardiovascular disease (CVD) to evaluate differences between Mexican American immigrants and the U.S.-born population.

METHODS AND RESULTS

Data from the Cameron County Hispanic Cohort (N=1,559). Average total risk scores were generated by age group for each gender. Regression analysis was conducted adjusting for covariates and interaction effects. Both women and men in the CCHC sample who were long-term immigrant residents (mean FRS scores women 4.2 with p<.001 vs. men 4.0 with p<.001) or born in the U.S. (mean FRS scores women 4.6 with p<.001 vs. men 3.3 with p<.001) had significantly higher risk scores than immigrants who had only been in this country for less than 10 years. The interaction model indicates that differences between immigrant and native-born Mexican Americans are most greatly felt at lowest levels of socioeconomic status for men in the CCHC.

CONCLUSIONS

This study suggests that in terms of immigrant advantage in CVD risk, on whom, where, and how the comparisons are being made have important implications for the degree of difference observed.

Association study of candidate gene polymorphisms and obesity in a young Mexican-American population from South Texas

BACKGROUND AND AIMS

Obesity is increasingly a health problem and a risk factor for diabetes in young Mexican-American populations. Genetic association studies in older, mostly non-Hispanic populations have reported that polymorphisms in the candidate genes HSD11B1, CRP, ADIPOQ, PPARG, ANKK1, ABCC8 and SERPINF1 are associated with obesity or diabetes. We analyzed the polymorphisms rs846910, rs1205, rs1501299, rs1801282, rs1800497, rs757110 and rs1136287 in these candidate genes, for association with obesity and metabolic traits in a young Mexican-American population from south Texas.

METHODS

Genotyping of the seven common SNPs were performed by allelic discrimination assays in 448 unrelated Mexican Americans (median age = 16 years) from south Texas. χ(2) tests and regression analyses using additive models were used for genetic association analyses adjusting for covariates; p values were corrected for multiple testing by permutation analyses.

RESULTS

rs1800497 (ANKK1) shows association with waist circumference (p = 0.009) and retains the association (p = 0.03) after permutation testing. Analysis of metabolic quantitative traits shows that rs846910 (HSD11B1) was associated with HOMA-IR (p = 0.04) and triglycerides (p = 0.03), and rs1205 (CRP) with HOMA-IR (p = 0.03) and fasting glucose levels (p = 0.007). However, the quantitative traits associations are not maintained after permutation analysis. None of the other SNPs in this study showed associations with obesity or metabolic traits in this young Mexican-American population.

CONCLUSIONS

We report a potential association between rs1800497 (linked to changes in brain dopamine receptor levels) and central obesity in a young Mexican-American population.

Defining the research agenda to reduce the joint burden of disease from diabetes mellitus and tuberculosis

The steadily growing epidemic of diabetes mellitus poses a threat for global tuberculosis (TB) control. Previous studies have identified an important association between diabetes mellitus and TB. However, these studies have limitations: very few were carried out in low-income countries, with none in Africa, raising uncertainty about the strength of the diabetes mellitus-TB association in these settings, and many critical questions remain unanswered. An expert meeting was held in November 2009 to discuss where there was sufficient evidence to make firm recommendations about joint management of both diseases, to address research gaps and to develop a research agenda. Ten key research questions were identified, of which 4 were selected as high priority: (i) whether, when and how to screen for TB in patients with diabetes mellitus and vice versa; (ii) the impact of diabetes mellitus and non-diabetes mellitus hyperglycaemia on TB treatment outcomes and deaths, and the development of strategies to improve outcomes; (iii) implementation and evaluation of the tuberculosis 'DOTS' model for diabetes mellitus management; and (iv) the development and evaluation of better point-of-care diagnostic and monitoring tests, including measurements of blood glucose and glycated haemoglobin A(1c) (HbA(1c)) for patients with diabetes mellitus. Implementation of this research agenda will benefit the control of both diseases.

Persistent infection with West Nile virus years after initial infection

West Nile virus (WNV) RNA was demonstrated in 5 (20%) of 25 urine samples collected from convalescent patients 573-2452 days (1.6-6.7 years) after WNV infection. Four of the 5 amplicons sequenced showed >99% homology to the WNV NY99 strain. These findings show that individuals with chronic symptoms after WNV infection may have persistent renal infection over several years.

Evaluation of blood bank practices in Karachi, Pakistan, and the government's response

BACKGROUND

National legislation in Pakistan regulating blood banks has been introduced several times, but has never been passed. To support provincial-level efforts to develop legislation we conducted a study to evaluate blood-banking practices in Karachi, Pakistan, to identify areas that could be improved.

METHODS

Thirty-seven blood banks were randomly selected from a list of 87 Karachi blood banks. The research team interviewed blood bank personnel, inspected available facilities and equipment, and observed blood collection using structured questionnaires and observation forms.

RESULTS

Of the 37 selected facilities, 25 were operational and 24 agreed to participate. Twelve (50%) of the facilities reported regularly utilizing paid blood donors, while only six (25%) actively recruited volunteer donors. During observation only 8% of facilities asked donors about injecting drug use, and none asked donors any questions about high-risk sexual behaviour. While 95% of blood banks had appropriate equipment and reagents to screen for hepatitis B, only 55% could screen for HIV and 23% for hepatitis C. Twenty-nine percent of the facilities were storing blood products outside the WHO recommended temperature limits.

IMPLICATIONS

Practives at most Karachi blood banks fell well below WHO standards. Findings from this study were instrumental in developing and passing legislation to regulate blood transfusion throughout Sindh Province, and suggest a method for improving blood transfusion practices in other developing countries (HPP 15 (2):217-22).

High frequency of chronic end-stage liver disease and hepatocellular carcinoma in a Hispanic population

BACKGROUND

Texas has the highest mortality from hepatocellular carcinoma in the USA. Because end-stage liver disease mortality is most marked in the Hispanic population in the Lower Rio Grande Valley, the aim of the present paper was to estimate the prevalence of end-stage liver disease and associated factors in Brownsville.

METHODS

A cross-sectional study was carried out, abstracting medical charts in a community-based clinic and a hospital. A matched case-control analysis was performed. Cases had an International Classification of Disease (9th revision; ICD9) code 155.0 or 571.0-9 (primary liver cancer or chronic liver disease) recorded; age- and sex-matched controls did not have these codes. A total of 176 cases and 352 controls was collected. The main outcome measure was the prevalence and risk factors for end-stage liver disease.

RESULTS

Conservative prevalence of end-stage liver disease: 126/100,000 (386/100,000, male). Eleven out of 176 had hepatocellular carcinoma. Median age was 57 years; 72% male, 94% Hispanic. Among significant risk factors were history of hepatitis (odds ratio (OR): 19.3; 95% confidence interval (CI): 8.0-46.4), any history of alcohol use (OR: 6.6; 95%CI: 4-10.8) and history of illegal drug use (OR: 1.9; 95%CI: 1.2-2.9). Fifteen cases with no known risk factors were classified as cryptogenic cirrhosis. Only four cases out of 176 had been referred for liver transplant.

CONCLUSIONS

The prevalence of end-stage liver disease in the Lower Rio Grande Valley is extremely high, with no single satisfactory explanation and with acute health disparities. Careful follow up of cryptogenic cirrhosis in this population may or may not lead to a new source of liver disease.

Serological response and poliovirus excretion following different combined oral and inactivated poliovirus vaccines immunization schedules

A controlled study was conducted in Karachi, Pakistan to compare humoral and mucosal immune responses against polioviruses in infants who received oral poliovirus vaccine (OPV) at birth and at 6, 10, and 14 weeks according to the Expanded Program on Immunization (EPI) with infants who received either three doses of inactivated poliovirus vaccine (IPV) at 6, 10, and 14 weeks together with OPV or one additional dose of IPV at 14 weeks together, with the last dose of OPV. A total of 1429 infants were enrolled; 24-week serum specimens were available for 898 infants (63%). They all received a challenge dose of OPV type 3 at 24 weeks of age. The addition of three doses of IPV to three doses of OPV induced a significantly higher percentage of seropositive children at 24 weeks of age for polio 1 (97% versus 89%, P<0.001) and polio 3 (98% versus 92%) compared to the EPI schedule. However, the one supplemental dose of IPV at 14 weeks did not increase the serological response at 24 weeks. Intestinal immunity against the challenge dose was similar in the three groups. Combined schedules of OPV and IPV in the form of diphtheria-pertussis-tetanus-IPV vaccine (DPT-IPV) may be useful to accelerate eradication of polio in developing countries.

Patients' perceptions of blood transfusion risks in Karachi, Pakistan

OBJECTIVE

To evaluate the understanding of and attitudes toward risks of blood transfusions among transfusion recipients in Karachi.

METHODS

One hundred forty-one transfusion recipients from 13 major Karachi hospitals were interviewed. Indications for transfusion were obtained by reviewing the patients' medical records.

RESULTS

The most common indications for transfusion were surgical complications (n = 77, 55%), anemia (n = 34, 24%), and generalized weakness (n = 15, 11%). Most recipients (n = 103, 80%) had never heard of viral hepatitis, and 44 (31%) had never heard of acquired immunodeficiency syndrome (AIDS). Ninety-four recipients (66%) believed that generalized weakness was a valid indication for blood transfusion. Sixty-nine recipients (49%) were not willing to pay an increased price for blood that was screened for blood-borne pathogens.

CONCLUSIONS

Blood recipients in Karachi are unaware of the risks of transfusions, and the reasons given by the ordering physician for many of the transfusions were not consistent with international guidelines. Steps to educate the public about the risks of transfusions and practitioners about the indications for transfusion could prevent blood-borne virus transmission in Karachi.

Evaluation of blood bank practices in Karachi, Pakistan, and the government's response

BACKGROUND

National legislation in Pakistan regulating blood banks has been introduced several times, but has never been passed. To support provincial-level efforts to develop legislation we conducted a study to evaluate blood-banking practices in Karachi, Pakistan, to identify areas that could be improved.

METHODS

Thirty-seven blood banks were randomly selected from a list of 87 Karachi blood banks. The research team interviewed blood bank personnel, inspected available facilities and equipment, and observed blood collection using structured questionnaires and observation forms.

RESULTS

Of the 37 selected facilities, 25 were operational and 24 agreed to participate. Twelve (50%) of the facilities reported regularly utilizing paid blood donors, while only six (25%) activity recruited volunteer donors. During observation only 8% of facilities asked donors about injecting drug use, and none asked donors any questions about high-risk sexual behaviour. While 95% of blood banks had appropriate equipment and reagents to screen for hepatitis B, only 55% could screen for HIV and 23% for hepatitis C. Twenty-nine percent of the facilities were storing blood products outside the WHO recommended temperature limits.

IMPLICATIONS

Practices at most Karachi blood banks fell well below WHO standards. Findings from this study were instrumental in developing and passing legislation to regulate blood transfusion throughout Sindh Province, and suggest a method for improving blood transfusion practices in other developing countries.

Limited effectiveness of home drinking water purification efforts in Karachi, Pakistan

OBJECTIVE

In many developing-country urban areas, municipally supplied water is not microbiologically safe. This study evaluated drinking water quality and effect of home water purification efforts in Karachi, Pakistan.

METHODS

Members of 300 households, including 100 households who used the Aga Khan University Hospital Laboratory and 200 of their neighbors were interviewed. In 293 consenting households, structured observations were performed and drinking water was analyzed for the presence of coliforms, using the multiple tube fermentation technique.

RESULTS

Although 193 of the 293 households (66%) reported using some method to purify their drinking water, including 169 (58%) who boiled their water, only 48 (16%) of the drinking water samples were free of coliforms. Although a combination of boiling and filtering was the most effective method of purification, only 38% of samples that had been boiled and filtered were free of coliforms.

CONCLUSIONS

Further refinements and evaluations of home-based efforts to purify and store water are needed.

Unsafe injections and the transmission of hepatitis B and C in a periurban community in Pakistan

Following reports of frequent deaths associated with jaundice and chronic liver disease among adults in a periurban community of Karachi, Pakistan, an investigation was conducted to evaluate the relationship between injections and viral hepatitis infections, to identify the reasons why patients received frequent injections, and to observe the injection practices employed in clinics. Two hundred and three adult patients were interviewed as they left each of the 18 area clinics. Practitioners were interviewed and three consecutive injections were observed at each clinic. Eighty-one per cent of patients received an injection on the day of the interview. Of the 135 patients who provided a serum sample, 59 (44%) had antibodies against hepatitis C virus and 26 (19%) had antibodies against hepatitis B virus. Patients who received more injections were more likely to be infected with hepatitis C. If oral and injected medications were equally effective, 44% of patients preferred injected medication. None of the practitioners knew that hepatitis C could be transmitted by injections. Non-sterile syringes and needles that had been used earlier in the day on other patients were used for 94% of the observed injections. Interventions to limit injections to those which are safe and clinically indicated are needed to prevent injection-associated infections in Pakistan and other low-income countries.

Outbreak of Crimean-Congo haemorrhagic fever in Quetta, Pakistan: contact tracing and risk assessment

In December 1994 in a private hospital in Quetta, Pakistan, 3 health-workers contracted Crimean-Congo haemorrhagic fever (CCHF) after surgery on a bleeding patient who later died. We conducted a retrospective study to determine transmission risks among contacts. Fifty contacts gave blood for antibody tests and answered questions about exposure. Two of four people exposed percutaneously and one of five with cutaneous exposure contracted CCHE The person with cutaneous exposure was a surgeon who tore his glove during surgery and noted blood on his hand but no cut. There were no anti-CCHF antibodies or CCHF cases among persons whose skin came into contact with body fluids other than blood (0/4), who had skin-to-skin contact (0/16) with patients or were physically close to them (0/21). Three index case relatives reported that although 10 family members had cutaneous exposure, none developed CCHF. The family refused blood tests. CCHF transmission in resource-constrained settings can be limited by focusing on avoiding health worker contact with blood.

HIV antibody seroprevalence and associated risk factors in sex workers, drug users, and prisoners in Sindh, Pakistan

OBJECTIVE

To determine prevalence of HIV infection and risk behaviors in commercial sex workers (CSWs), drug users, and prisoners in Sindh, Pakistan.

METHODS

A medical clinic was established in a "red-light" district of Karachi. Eighty-one CSWs who registered at the clinic between November 1993 and June 1994 were provided HIV counseling and testing and administered a risk factor questionnaire. Next, 316 male drug users were tested for HIV-1 antibody from April to July 1994. Finally, a voluntary serosurvey of HIV-1 and HIV-2 and risk behaviors of 3525 prisoners in Sindh was conducted between July 1994 and December 1994. Abbott Recombinant HIV third-generation enzyme-linked immunosorbent assay (ELISA) and confirmatory testing with Western blot analysis were used in all three groups.

RESULTS

None of 81 CSWs tested for HIV-1 antibody were positive. None of 316 drug users tested positive for HIV-1 antibody. Of 3441 male prisoners, 1 was HIV-1 infected, and of 84 female prisoners, 1 was HIV-1 infected. No prisoner was positive for HIV-2 antibody.

DISCUSSION

The prevalence of HIV in CSWs, drug users, and prisoners in Sindh is low at present. Intervention programs implemented at this stage can make an impact in HIV prevention.

The relationship between therapeutic injections and high prevalence of hepatitis C infection in Hafizabad, Pakistan

To determine the prevalence and routes of transmission of hepatitis C virus (HCV) infection in Hafizabad, Pakistan, we collected sera in 1993 from a geographically based random sample of residents, and in 1994 identified 15 HCV-infected individuals (cases) and 67 age and sex matched uninfected individuals (controls). Initially we approached 504 households, and collected serum from a randomly selected household member in 309 (64%). Twenty persons (6.5%) had anti-HCV antibody; 31% percent had hepatitis B core antibodies, and 4.3% had hepatitis B surface antigen. In the case-control study, persons who received more therapeutic injections (categorized as averaging 1, 2-4, 5-9 or > 10 injections per year in the previous 10 years) were more likely to be infected with HCV (odds ratio 0, 1.5, 2.5 and 6.9 respectively, P = 0.008) compared to persons averaging 0 injections per year. Efforts to limit therapeutic injections to only those that are medically indicated and that use sterile equipment are essential in order to prevent transmission of HCV.

Treatment options for vulvovaginal candidiasis, 1993

Vulvovaginal candidiasis (VVC), the second most common form of vaginitis, particularly affects women of childbearing age. Since the 1970s, several new agents have become available for the treatment of VVC. This review focuses on options for the treatment of this condition, critically evaluating the relevant published studies. For the treatment of acute episodes of VVC in nonpregnant women, several topical and oral antifungal agents are clinically and mycologically effective. Topical agents should be considered the first line of therapy; however, oral agents are sometimes associated with better compliance among patients. For acute episodes in pregnant women, a topical agent is the treatment of choice. Until data become available on the treatment of VVC in women infected with human immunodeficiency virus (HIV), the same approach as that used for women without HIV infection should be considered as previously written. For recurrent VVC, the optimal maintenance therapy has not yet been established; however, administration of low-dose oral ketoconazole (100 mg/d) has proven effective. Well-designed studies of the best therapy for VVC in women with HIV infection and for recurrent VVC are urgently needed.

Serum antibodies to structural proteins of hantavirus arise at different times after infection

An enzyme-linked immunosorbent assay (ELISA) was developed for the quantification of serum antibodies against group-specific epitopes of the glycoproteins (G1, G2) and nucleoprotein (NP) of the genus Hantavirus. This assay was used to study the kinetics of the development of serum antibodies after natural infection with Puumala-like virus in humans. To this end a panel of 34 serum samples collected from individuals at different times after natural infection was tested by the ELISA. The samples were also tested for specific IgM and IgG levels against Puumala-like virus, which provided confirmatory data about the presumed timing of infection. It was shown that serum antibodies against the G1 epitope were present in the acute and early convalescent period just before antibodies to the NP epitope could be demonstrated. In contrast, antibodies to two G2 epitopes were present not earlier than in the convalescent and late convalescent period. Since all these categories of antibodies seem to persist for long periods, antibodies against the G1 epitope and the NP epitope may be of specific diagnostic value. Furthermore, levels of G1-specific antibodies and antibodies to either NP or G2 may allow estimation of the time elapsed following initial infection.

Hematologic dysfunction in Lassa fever

Lassa fever is widespread in West Africa, where the case fatality is about 16% in hospitalized adult patients. The clinical course is highly variable, with a few patients developing severe disease with bleeding, adult respiratory distress syndrome, encephalopathy and hypovolemic shock. We studied 70 patients admitted with suspected Lassa fever to a hospital in Sierra Leone, West Africa. Fourteen patients classified as having severe Lassa fever on the basis of serum aspartate amino transferase (AST) greater than 150 IU/L or viremia of greater than 10(3.6) tissue culture infective dose (TCID) 50/ml were found to have statistically significantly depressed lymphocyte counts when compared with patients with mild Lassa fever (AST less than 150 IU/L or viremia, less than 10(3.6)TCID50/ml), (P less than 0.0001) and with febrile control patients, in whom Lassa infection had been excluded by laboratory criteria (P less than 0.0008). Maximum depression occurred a mean of 10.9 days post onset. Patients with severe Lassa fever also had moderate thrombocytopenia, which was statistically significant when compared with febrile control patients (P less than 0.0003) and this occurred a mean of 10.8 days postonset. The most significant changes were in platelet function, which was markedly depressed in patients with severe Lassa fever (P less than 0.0035 in response to ADP and P = 0.0081 for collagen) when compared with patients with mild Lassa fever, and when compared with febrile controls, (P = 0.0013 for ADP and P less than 0.00001 for collagen). This abnormality was usually maximal on admission to hospital, and probably is an early event, preceding hospitalization in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody against viruses in maternal and cord sera: non-specific inhibitors are found to higher titre on the maternal side of the circulation

Pregnancies were identified in which maternal IgG antibodies against rubella virus were not detectable by single radial haemolysis. Twenty paired maternal/cord sera were then tested for haemagglutination-inhibiting (HI) activity against rubella virus without kaolin pretreatment of the sera. In the absence of specific antibody, the HI activity observed could thus be ascribed to the effect of non-specific inhibitors. The HI activity in maternal sera was significantly (P less than 0.001) higher than that in cord sera. The 20 pairs of sera were similarly tested against a bunyavirus, an alphavirus and a flavivirus, both with and without kaolin pretreatment. The results showed non-specific inhibitors were found to higher titre in maternal sera, with the difference being statistically significant (P less than 0.001) for each of the three viruses.

Radial haemolysis for the detection of rubella antibody in acute postnatal rubella

One hundred and forty-eight sera from 101 cases of acute postnatal rubella were examined by the radial haemolysis (RH) technique currently recommended by the Public Health Laboratory Service of the United Kingdom. In 75 cases the date of onset of rash was known. No sera were RH positive until the third day after the onset of rash and one serum was still negative at 9 days. By 10 days all sera gave a zone of at least 10 mm. The antibody response detected by RH appears later than that detected by haemagglutination inhibition (HI). Thirty-nine of the 101 cases could be diagnosed by seroconversion or a significant rise in titre using the HI test (diagnosis of the remainder depending upon rubella-specific IgM tests). Using the RH test this figure rises to 48 but in ten of these cases reliance on RH would have meant a delay in diagnosis. The results also indicate that many more sera would need to be tested for rubella-specific IgM if the RH test was used instead of the HI test for evaluating possible cases and contacts of rubella.

Legionnaires' disease in a transplant unit: isolation of the causative agent from shower baths

Legionnaires' disease was diagnosed in two patients in a transplant unit, both patients having occupied the same postoperative cubicle shortly before onset of their illnesses. Legionella pneumophila was found in water taken from the cubicle shower bath and from other showers in the unit. To eradicate the legionellae, the water supply was treated with chlorine, but this had only a temporary effect.

Identification of a clinical isolate as Legionella pneumophila by gas chromatography and mass spectrometry of cellular fatty acids

Culture of a bronchial aspirate from an immunosuppressed patient with severe pneumonia yielded a growth of filamentous poorly staining gram-negative rods. Fluorescence with Legionella pneumophila direct fluorescein-isothiocyanate conjugate was equivocal. Gas-liquid chromatography (GLC) and GLC/mass-spectrometry (GLC-MS) of the cellular fatty acids of the isolate confirmed that the organism was L. pneumophila. GLC and GLC-MS constitute a rapid and definitive method for identification of L. pneumophila isolates.