Gordon P. Watt

Cirrhosis and Advanced Fibrosis in Hispanics in Texas: The Dominant Contribution of Central Obesity.

Liver cirrhosis is a leading cause of death in Hispanics and Hispanics who live in South Texas have the highest incidence of liver cancer in the United States. We aimed at determining the prevalence and associated risk factors of cirrhosis in this population. Clinical and demographic variables were extracted for 2466 participants in the community-based Cameron County Hispanic Cohort in South Texas. Aspartate transaminase to Platelet Ratio Index (APRI) was used to predict cirrhosis in Cameron County Hispanic Cohort. The prevalence of cirrhosis using APRI≥2 was 0.94%, which is nearly 4-fold higher than the national prevalence. Using APRI≥1, the overall prevalence of cirrhosis/advanced fibrosis was 3.54%. In both analyses, highest prevalence was observed in males, specifically in the 25–34 age group. Risk factors independently associated with APRI≥2 and APRI≥1 included hepatitis C, diabetes and central obesity with a remarkable population attributable fraction of 52.5% and 65.3% from central obesity, respectively. Excess alcohol consumption was also independently associated with APRI≥2. The presence of patatin-like phospholipase domain-containing-3 gene variants was independently associated with APRI≥1 in participants >50 years old. Males with both central obesity and excess alcohol consumption presented with cirrhosis/advanced fibrosis at a young age. Alarmingly high prevalence of cirrhosis and advanced fibrosis was identified in Hispanics in South Texas, affecting young males in particular. Central obesity was identified as the major risk factor. Public health efforts are urgently needed to increase awareness and diagnosis of advanced liver fibrosis in Hispanics.

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.

Hepatitis C virus in Mexican Americans: a population-based study reveals relatively high prevalence and negative association with diabetes

This study aimed to estimate the prevalence and risk factors for hepatitis C virus (HCV) infection in Mexican Americans living in South Texas. We tested plasma for the presence of HCV antibody from the Cameron County Hispanic Cohort (CCHC), a randomized, population-based cohort in an economically disadvantaged Mexican American community on the United States/Mexico border with high rates of chronic disease. A weighted prevalence of HCV antibody of 2·3% [n = 1131, 95% confidence interval (CI) 1·2-3·4] was found. Participants with diabetes had low rates of HCV antibody (0·4%, 95% CI 0·0-0·9) and logistic regression revealed a statistically significant negative association between HCV and diabetes (OR 0·20, 95% CI 0·05-0·77) after adjusting for sociodemographic and clinical factors. This conflicts with reported positive associations of diabetes and HCV infection. No classic risk factors were identified, but important differences between genders emerged in analysis. This population-based study of HCV in Mexican Americans suggests that national studies do not adequately describe the epidemiology of HCV in this border community and that unique risk factors may be involved.

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.

Prevalence of aflatoxin-associated TP53R249S mutation in hepatocellular carcinoma in Hispanics in South Texas

We aimed to determine whether aflatoxin dietary exposure plays a role in the high incidence of hepatocellular carcinoma (HCC) observed among Hispanics in South Texas.We measured TP53R249S somatic mutation, hallmark of aflatoxin etiology in HCC, using droplet digital PCR and restriction fragment length polymorphism. TP53R249S mutation was detected in 3 out of 41 HCC tumors from Hispanics in South Texas (7.3%). We also measured TP53R249S mutation in plasma cell free DNA (cfDNA) from 218 HCC patients and 96 Hispanic subjects with advanced fibrosis or cirrhosis, from South Texas. The mutation was detected only in Hispanic and Asian HCC patients and patients harboring TP53R249S mutation were significantly younger and had a shorter overall survival. The mutation was not detected in any Hispanic subject with advanced fibrosis or cirrhosis. Genes involved in cell cycle control of chromosomal replication and in BRCA1-dependent DNA damage response were enriched in HCCs with TP53R249S mutation. The E2F1 family members, E2F1 and E2F4, were identified as upstream regulators. TP53R249S mutation was detected in 5.7%-7.3% of Hispanics with HCC in South Texas. This mutation was associated with a younger age and worse prognosis. TP53R249S was however not detected in Hispanics in South Texas with cirrhosis or advanced fibrosis. Aflatoxin exposure may contribute to a small number of HCCs in Hispanics in South Texas but the detection of TP53R249S mutation in plasma cfDNA is not a promising biomarker of risk assessment for HCC in subjects with cirrhosis or advanced fibrosis in this population.

Toll-like receptor 4: a target for chemoprevention of hepatocellular carcinoma in obesity and steatohepatitis

The incidence of hepatocellular carcinoma (HCC) associated with non-alcoholic fatty liver disease (NAFLD) is rapidly increasing. We aimed to elucidate the genetic basis of NAFLD-associated HCC and identify candidate targets for chemoprevention. Twenty HCC tumors, distant liver and matched tails from mice with hepatocyte-deletion of Pten (HepPten-) were subjected to whole-exome sequencing. A total of 162 genes with somatic non-synonymous single nucleotide variants or exonic small insertions and deletions in tumors were identified. Ingenuity Pathway Analysis of these 162 genes, further identified Toll-like receptor (TLR) 4, a key mediator of proinflammatory responses, and resatorvid, a TLR4 inhibitor, as the main causal networks of this dataset. Resatorvid treatment strongly prevented HCC development in these mice (p < 0.001). Remarkably, HCC patients with high tumoral TLR4 mRNA expression were more likely to be diagnosed with NAFLD and obese. TLR4 mRNA expression positively correlated with IL-6 and IL-10 mRNA expression in HCC tumors and the correlation was stronger in obese HCC patients. We have identified tumor mutation signatures and associated causal networks in NAFLD-associated HCC in HepPten- mice and further demonstrated the important role of TLR4 in promoting HCC development. This study also identified IL-6 and IL-10 as markers of TLR4 activation in HCC and subjects with NAFLD and obesity as the target population who would benefit from TLR4 inhibition treatment for HCC chemoprevention.

Glycemic Control and Bone Turnover in Older Mexican Americans with Type 2 Diabetes

Altered bone quality, caused by underlying metabolic changes of type 2 diabetes (T2D), has been hypothesized to cause altered bone strength and turnover leading to increased fracture risk in T2D patients. Current understanding about changes in bone turnover markers in T2D patients is mainly based on studies focused on Caucasian men and women. However, Hispanic populations have the highest prevalence of both T2D and osteoporosis in the US. We investigated associations of glycemic control (in terms of glycated hemoglobin [HbA1c]) and bone turnover rate in 69 older (≥50 years) Mexican American Cameron County Hispanic Cohort (CCHC) participants with T2D. Multivariable analyses were conducted to assess the associations between HbA1c (%), serum osteocalcin (OC), and serum sclerostin. In agreement with published reports from other racial/ethnic populations, our study found that lower bone turnover (indicated by lower serum OC) occurred in Mexican American men with T2D who had poorer glycemic control. For the women in our study, we found no significant association between glycemic control and OC. In contrast, HbA1c was positively associated with sclerostin for women, with near significance (p = 0.07), while no association was found in men. We recommend screening Mexican American individuals with T2D, specifically those with poor glycemic control, for bone loss and fracture risk.

Telomerase reverse transcriptase mutations in plasma DNA in patients with hepatocellular carcinoma or cirrhosis: Prevalence and risk factors

Telomerase reverse transcriptase (TERT) mutation is the most frequent genetic alteration in hepatocellular carcinoma (HCC). Our aims were to investigate whether TERT mutations can be detected in circulating cell‐free DNA (cfDNA) of patients with HCC and/or cirrhosis and characterize clinical parameters associated with these mutations. We retrieved data on TERT C228T and C250T promoter mutations in 196 HCCs from The Cancer Genome Atlas. We measured these TERT mutations in plasma cfDNA in 218 patients with HCC and 81 patients with cirrhosis without imaging evidence of HCC. The prevalence of TERT mutations in The Cancer Genome Atlas HCC specimens was 44.4%. TERT mutations were detected with similar prevalence (47.7%) in plasma cfDNAs from 218 patients with HCC. TERT mutations, either within the HCC or in cfDNA, were associated with male sex, hepatitis C virus (HCV), alcoholic cirrhosis, family history of cancer, and poor prognosis. The high prevalence of TERT mutations in HCCs in male patients with cirrhosis caused by HCV and/or alcohol was confirmed in an independent set of HCCs (86.6%). Finally, TERT mutations were detected in cfDNA of 7 out of 81 (8.6%) patients with cirrhosis without imaging evidence of HCC, including 5 male patients with cirrhosis due to HCV and/or alcohol. Genes involved in xenobiotic and alcohol metabolism were enriched in HCCs with TERT mutations, and vitamin K2 was identified as an upstream regulator. Conclusion: TERT mutations are detectable in plasma cfDNA. Long‐term imaging surveillance of patients with cirrhosis with cfDNA TERT mutations without evidence of HCC is required to assess their potential as early biomarkers of HCC. (Hepatology Communications 2018;2:718‐731)

High Prevalence of Hepatic Fibrosis, Measured by Elastography, in a Population-Based Study of Mexican Americans

BACKGROUND & AIMS: Hepatic fibrosis is a primary risk factor for cirrhosis and hepatocellular carcinoma, which affect a disproportionate number of Hispanics in the United States. We aimed to determine the prevalence of significant fibrosis, measured by point shear‐wave elastography (pSWE), and determine characteristics of hepatic fibrosis and simple steatosis in a population‐based study of Mexican American Hispanics in south Texas. METHODS: Liver stiffness was measured by pSWE, performed by 2 separate operators, for 406 participants in the Cameron County Hispanic Cohort from 2015 through 2017. Significant fibrosis (F2–F4) was defined as median stiffness > 1.34 m/s. Steatosis was determined by ultrasound. All participants underwent a clinical examination that included a comprehensive laboratory analysis and standardized interview about their medical and social history. We calculated weighted prevalence of fibrosis and determined clinical and demographic associations with significant fibrosis (with or without steatosis) and simple steatosis with no/minimal fibrosis using multinomial logistic regression. RESULTS: Fifty‐nine participants were excluded due to unreliable pSWE findings or inconclusive ultrasound results, for a final analysis of 347 participants. The prevalence of significant fibrosis was 13.8%; most of these participants (37/42, 88.1%) had no evidence of viral hepatitis or heavy drinking. Levels of liver enzymes were associated with fibrosis and simple steatosis. Indicators of metabolic health (insulin resistance, triglycerides, and cholesterol) were significantly associated with simple steatosis. Fibrosis, but not simple steatosis, was significantly associated with of antibodies against HCV in plasma (odds ratio, 18.9; P = .0138) and non‐significantly associated with reduced platelet count (odds ratio, 0.8 per 50x103/&mgr;L; 95% CI, 0.5–1.1). Multivariable analyses, as well as sensitivity analyses removing F4 fibrosis and viral or alcoholic etiologies, confirmed our results. CONCLUSION: We estimated the prevalence of fibrosis in a large population of Mexican American Hispanics using pSWE measurements. We found Mexican American Hispanics to have a higher prevalence of fibrosis compared to European and Asian populations, primarily attributable to metabolic disease.

Mexican American and South Asian population-based cohorts reveal high prevalence of type 2 diabetes and crucial differences in metabolic phenotypes

Objective Prevalence of type 2 diabetes varies by region and ancestry. However, most guidelines for the prevention of diabetes mellitus (DM) are based on European or non-Hispanic white populations. Two ethnic minority populations—Mexican Americans (MAs) in Texas, USA, and South Indians (SIs) in Tamil Nadu, India—have an increasing prevalence of DM. We aimed to understand the metabolic correlates of DM in these populations to improve risk stratification and DM prevention. Research design and methods The Cameron County Hispanic Cohort (CCHC; n=3023) served as the MA sample, and the Population Study of Urban, Rural, and Semi-Urban Regions for the Detection of Endovascular Disease (PURSE; n=8080) served as the SI sample. Using design-based methods, we calculated the prevalence of DM and metabolic comorbidities in each cohort. We determined the association of DM with metabolic phenotypes to evaluate the relative contributions of obesity and metabolic health to the prevalence of DM. Results In the CCHC (overall DM prevalence 26.2%), good metabolic health was associated with lower prevalence of DM, across age groups, regardless of obesity. In PURSE (overall prevalence 27.6%), probability of DM was not strongly associated with metabolic phenotypes, although DM prevalence was high in older age groups irrespective of metabolic health. Conclusion Our study provides robust, population-based data to estimate the prevalence of DM and its associations with metabolic health. Our results demonstrate differences in metabolic phenotypes in DM, which should inform DM prevention guidelines in non-European populations.