Dietary oily fish intake reduces the risk of all-cause mortality in frequent fish consumers of Amerindian ancestry living in coastal Ecuador: the Atahualpa project.

PURPOSE: To assess the relationship between dietary oily fish intake and all-cause mortality in a population of frequent fish consumers of Amerindian ancestry living in rural Ecuador. METHODS: Individuals aged ≥ 40 years enrolled in the prospective population-based Atahualpa Project cohort received annual questionnaires to estimate their dietary oily fish intake. Only fish served broiled or cooked in the soup were included for analysis. Poisson regression and Cox-proportional hazards models adjusted for demographics, education level and cardiovascular risk factors were obtained to estimate mortality risk according to the amount of oily fish intake stratified in tertiles. RESULTS: Analysis included 909 individuals (mean age: 55.1 ± 12.8 years) followed by a median of 7.5 ± 3 years. Mean oily fish intake was 9.4 ± 5.7 servings per week. A total of 142 (16%) individuals died during the follow-up. The mortality rate for individuals in the first tertile de oily fish intake (0.0-6.29 servings) was 2.87 per 100 person-years, which decreased to 1.78 for those in the third tertile (10.59-35.0 servings). An adjusted Cox-proportional hazards model showed that individuals allocated to the second (HR 0.61; 95% CI 0.41-0.92) and third (HR 0.60; 95% CI 0.40-0.91) tertiles of dietary oily fish intake had significantly lower mortality risk than those in the first tertile. CONCLUSION: Sustained oily fish intake of more than six servings per week reduces mortality risk in middle-aged and older adults of Amerindian ancestry.

Total Cerebral Small Vessel Disease Score and Anthropometric Indices: A Population-Based Study in Older Adults of Amerindian Ancestry.

A total of 590 older adults of Amerindian ancestry living in rural Ecuador received anthropometric measurements and a brain magnetic resonance imaging to estimate the total cerebral small vessel disease (cSVD) score. A fully adjusted ordinal logistic regression model, with categories of the total cSVD score as the dependent variable, disclosed significant associations between the waist circumference, the waist-to-hip, and the waist-to-height ratios - but not the body mass index (BMI) - and the cSVD burden. Indices of abdominal obesity may better correlate with severity of cSVD than the BMI in Amerindians. Phenotypic characteristics of this population may account for these results.

Patterns of progression of cerebral small vessel disease markers in older adults of Amerindian ancestry: a population-based, longitudinal prospective cohort study.

BACKGROUND: Progression of cerebral small vessel disease (cSVD) markers has been studied in different races/ethnic groups. However, information from individuals of Amerindian ancestry is lacking. We sought to evaluate progression patterns of cSVD markers in community-dwelling older adults of Amerindian ancestry. METHODS: Following a longitudinal prospective study design, participants of the Atahualpa Project Cohort aged ≥ 60 years received a baseline brain MRI and clinical interviews. Those who also received a brain MRI at the end of the study were included. Poisson regression models were fitted to assess cSVD markers progression according to their baseline load after a median follow-up of 6.5 ± 1.4 years. Logistic regression models were fitted to assess interrelations in the progression of the different cSVD markers at the end of the study. RESULTS: The study included 263 individuals (mean age: 65.7 ± 6.2 years). Progression of white matter hyperintensities (WMH) was noticed in 103 (39%) subjects, cerebral microbleeds in 25 (12%), lacunes in 12 (5%), and enlarged basal ganglia-perivascular spaces (BG-PVS) in 56 (21%). Bivariate Poisson regression models showed significant associations between WMH severity at baseline and progression of WMH and enlarged BG-PVS. These associations became non-significant in multivariate models adjusted for clinical covariates. Logistic regression models showed interrelated progressions of WMH, cerebral microbleeds and enlarged BG-PVS. The progression of lacunes was independent. CONCLUSIONS: Patterns of cSVD marker progression in this population of Amerindians are different than those reported in other races/ethnic groups. The independent progression of lacunes suggests different pathogenic mechanisms with other cSVD markers.

The effect of previous strokes on the relationship between ankle-brachial index determinations and incident strokes: A population-based, longitudinal prospective study in older adults.

OBJECTIVE: Abnormal ankle-brachial index (ABI) determinations may be associated with an increased risk of incident strokes. However, the impact of previous strokes in this relationship is unknown. We estimated the role of previous strokes on the association between abnormal ABI determinations and incident stroke risk in community-dwelling older adults. METHODS: Atahualpa residents aged ≥60 years received ABI determinations, cardiovascular risk factors assessment, and brain MRIs. ABIs were classified as abnormal if ≤0.9 or ≥1.4. Incident strokes were diagnosed by a certified neurologist with the aid of a post-event MRI. Poisson regression models were fitted to estimate stroke incidence rate ratio (IRR) according to categories of ABI. RESULTS: Analysis included 389 participants (mean age: 68.2 ± 8.1 years). Eighty-six persons (22%) had abnormal ABI determinations. Incident strokes occurred in 38 (9.8%) individuals after a mean follow-up of 6.1 ± 1.9 years. Abnormal ABIs were associated with incident strokes in unadjusted analyses (p = 0.002) as well as in a Poisson regression model adjusted for demographics and clinical covariates (IRR: 2.57; 95% C.I.: 1.29-5.13), but not when the model was adjusted for neuroimaging covariates (IRR: 1.46; 95% C.I.: 0.67-3.20). Interaction models showed that having both abnormal ABI and non-lacunar strokes at baseline made the individual 9.7 times more likely to have an incident stroke (95% C.I.: 3.87-24.4). The risk was reduced to 2.2 (95% C.I.: 0.96-5.13) for those who only had an abnormal ABI. CONCLUSIONS: An abnormal ABI is associated with a doubling the risk of incident strokes, but its importance is superseded by history of non-lacunar strokes.

Height is Inversely Associated with Biomarkers of Intracranial Atherosclerotic Disease in Older Adults of Amerindian Ancestry: Exploring the Obesity Paradox.

BACKGROUND: Various anthropometric measurements have been inversely associated with atherosclerosis, giving rise to the concept of an "obesity paradox" However, inconsistent study results make it difficult to determine the best anthropometric measurement with which to assess such inverse relationship. Height has been inversely associated with atherosclerosis and it is unlikely to be associated with unexpected biases. In this study, we aimed to assess the association between height and other anthropometric measurements and intracranial atherosclerotic disease (ICAD). METHODS: Community-dwelling older adults enrolled in the Three Villages Study received anthropometric measurements, high-resolution head CT (to evaluate calcium content in carotid siphons) and time-of-flight MRA (to assess stenosis of large intracranial arteries). Logistic regression models were fitted to assess the independent association between each anthropometric measurements and the presence of ICAD, after adjusting for relevant confounders. Estimated adjusted proportions were used to show how increases of different anthropometric measurements impacted ICAD log odds and corresponding odds ratios. RESULTS: A total of 581 individuals were enrolled. Height was the single variable inversely associated with ICAD at the mean of other anthropometric measurements (OR: 0.954; 95% C.I.: 0.918 - 0.991; p=0.016). Every additional cm of height reduced by 4.6% the probability of having ICAD. The significance of other anthropometric measurements vanished in multivariate models with height as an independent variable. CONCLUSIONS: This study demonstrates a robust inverse association between height and ICAD in Amerindians and opens new avenues of research for a better understanding of the obesity paradox in diverse ethnic groups.

Health professionals and Amerindian patients: representations and practices in French Guiana / Professionnels de santé et patients amérindiens : représentations et pratiques en Guyane française

CONTEXT: In French Guiana, Amerindian populations find themselves in a health system whose therapeutic itinerary revolves around their traditional medicine and modern medicine provided by health professionals mostly from hexagonal France. The latter intervene in a “complexity of intercultural contact” which influences the caregiver-patient relationship and affects therapeutic adherence. METHOD: To better understand the practices and representations of the health system in an intercultural context, qualitative research was carried out in the field between 2018 and 2019 with seventeen health professionals working in health centers located in the municipalities of the Interior of French Guiana. Semi-structured individual interviews were conducted in order to explore the representations, the difficulties encountered, and the tools used by these caregivers in their daily practice. These interviews were crossed with participant observations and bibliographical research in the medical and anthropological fields. RESULTS: The caregiver-patient encounter was asymmetrical, unequal and was part of a power relationship. The caregivers remained marked by ethnocentric representations -inherent to each culture- far removed from those of the populations and this divergence impacted the practice. DISCUSSION: It would be advisable to shift the focus in order to « penetrate » the frame of reference of the Other and rebalance relationships. The exploration of popular knowledge and skills and the application of proven teaching methods would encourage therapeutic adherence. « Homethnic workers » and intercultural training could help promote community health.

Contexte: En Guyane française, les populations amérindiennes se retrouvent dans un système de santé dont l'itinéraire thérapeutique s'articule autour de leur médecine traditionnelle et d'une médecine moderne prodiguée par des professionnels de santé originaires, pour la plupart, de la France hexagonale. Ces derniers interviennent dans une « complexité de contact interculturel ¼ qui influence la relation soignant soigné et affecte l'adhésion thérapeutique. Méthode: Pour mieux comprendre les représentations et pratiques du système de santé en contexte interculturel, une recherche qualitative a été menée sur le terrain, en 2018 et 2019, auprès de dix-sept professionnels de santé exerçant dans les centres de santé situés dans les communes de l'Intérieur de la Guyane. Des entretiens individuels semi-structurés ont été menés afin d'explorer les représentations, les difficultés rencontrées et les outils mobilisés par ces soignants dans leur pratique courante. Ces entretiens ont été croisés avec des observations participantes et des recherches bibliographiques dans les champs médicaux et anthropologiques. Résultats: La rencontre soignant soigné était asymétrique, inégale et s'inscrivait dans un rapport de pouvoir. Les soignants restaient marqués de représentations ethnocentriques - inhérentes à chaque culture - éloignées de celles des populations amérindiennes, et cette divergence impactait la pratique. Discussion: Il conviendrait de se décentrer, pour « pénétrer ¼ dans le cadre de référence de l'Autre et rééquilibrer les rapports. L'exploration des savoirs et savoir-faire populaires et l'application de méthodes éprouvées d'enseignement encourageraient l'adhésion thérapeutique. Les « intervenants homethniques ¼ et une formation à l'interculturalité pourraient favoriser la promotion de la santé communautaire.

HLA-G in Mayas from Yucatan: An evolutionary approach.

HLA-G allele frequencies were studied in Yucatán (Mexico) Maya Amerindians by a direct exon DNA sequencing technique. It is described that Mayas are probably one of the first populations together with Olmecs that populated Meso America and that important HLA genetic differences between Mexican and Guatemalan Mayas support that Maya languages were imposed to several neighbouring Amerindian groups. HLA-G*01:01:02, HLA-G*01:01:01 and HLA-G*01:04:01 are the most frequent alleles in this population. It is remarkable that HLA-G*01:05N allele was not found in the population in accordance with similar results found in another Amerindians. Also, protein allele HLA-G*01:04 frequency is found not to differ to those found in another far or close living Amerindians in contrast to other World populations. It seems that while high HLA-G*01:05N frequency is found in Iran and Middle East populations, probably where this allele appeared within an ancestral HLA-A*19 group of alleles haplotype and it is maintained by unknown evolutionary forces, Amerindians do not have a high frequency because a founder effect or because required natural evolutionary forces do not exist in America. Finally, we believe useful to study HLA-G evolution for its physiopathology understanding in addition to the many papers on statistics on HLA-G and in vitro models that are yearly published.

Association between vitamin D deficiency and common variants of Vitamin D binding protein gene among Mexican Mestizo and indigenous postmenopausal women.

PURPOSE: Vitamin D deficiency (VDD) and polymorphisms in the group-specific component (GC) gene are known to be associated in different populations. However, the effects of such genetic variants may vary across different populations. Thus, the objective of this study was to estimate the association between Vitamin D-Binding Protein (VDBP) haplotypes and VDD in mestizo postmenopausal women and Mexican Amerindian ethnic groups. METHODS: This was a cross-sectional study of 726 postmenopausal Mexican women from the Health Workers Cohort Study (HWCS) and 166 postmenopausal women from the Metabolic Analysis in an Indigenous Sample (MAIS) cohort in Mexico. GC polymorphisms (rs7045 and rs4588) were analyzed by TaqMan probes. Serum 25-hydroxyvitamin D [25(OH)D] levels were measured by Chemiluminescent Microparticle Immuno Assay. RESULTS: The prevalence of VDD serum 25(OH)D < 20 ng/mL was 43.7% in mestizo women and 44.6% in indigenous women. In HWCS, the single nucleotide polymorphisms (SNPs) rs7041 and rs4588 were associated with VDD. In addition, women from the HWCS, carrying the haplotypes GC2/2 and GC1f/2 had higher odds of VDD (OR = 2.83, 95% CI 1.14, 7.02; and OR = 2.30, 95% CI 1.40, 3.78, respectively) compared to women with haplotype 1f/1 s. These associations were not statistically significant in the MAIS cohort. CONCLUSIONS: Our results show genetic association of the analyzed SNPs and related haplotypes, on the GC gene, with VDD in mestizo Mexican postmenopausal women. Moreover, a high prevalence of VDD with high genetic variability within the country was observed. Our results support the need for national policies for preventing VDD.

Prevalence and Correlates of Intracranial Atherosclerotic Disease Among Community-Dwelling Older Adults of Amerindian Ancestry. The Three Villages Study.

BACKGROUND: Knowledge on the prevalence and correlates of intracranial atherosclerotic disease (ICAD) is limited. We aimed to assess prevalence, clinical and neuroimaging correlates of ICAD in a cohort of older adults of Amerindian ancestry. METHODS: The study included 581 community-dwellers aged ≥60 years (mean age 71 ± 8.4 years; 57% women) living in rural Ecuadorian villages. ICAD was identified by means of CT determinations of carotid siphon calcifications (CSC) or MRA findings of significant stenosis of intracranial arteries. Fully-adjusted logistic regression models were fitted with biomarkers of ICAD as the dependent variables. RESULTS: A total of 205 (35%) of 581 participants had ICAD, including 185 with high calcium content in the carotid siphons and 40 with significant stenosis of at least one intracranial artery (20 subjects had both biomarkers). Increasing age, high fasting blood glucose, >10 enlarged basal ganglia-perivascular spaces and non-lacunar strokes were associated with high calcium content in the carotid siphons. In contrast, male gender, moderate-to-severe white matter hyperintensities, lacunar and non-lacunar strokes were associated with significant stenosis of intracranial arteries. Stroke was more common among subjects with any biomarker of ICAD than in those with no biomarkers (29% versus 9%, p < 0.001). Significant stenosis of intracranial arteries was more often associated with stroke than high calcium content in the carotid siphons, suggesting that CSC are more likely an ICAD biomarker than causally related to stroke. CONCLUSIONS: ICAD prevalence in Amerindians is high, and is significantly associated with stroke. CSC and significant stenosis of intracranial arteries may represent different phenotypes of ICAD.

Trachoma in 3 Amerindian Communities, Venezuelan Amazon, 2018.

Trachoma is among the most common infectious causes of blindness. During January-May 2018, a total of 4 trachoma cases were diagnosed among Amerindians of the Yanomami ethnic group in 3 communities of southern Venezuela. This country has social and environmental conditions conducive to the endemicity of this neglected tropical disease.

Improvements cardiometabolic risk factors in Latin American Amerindians (the Mapuche) with concurrent training.

Our aim was to investigate the effects of 12 weeks of CT (ie, high-intensity interval and resistance training) in Mapuche adults from Chile and in their peers of European descent. In total, 96 hyperglycemic adult women (mean age 46 years [95% confidence interval; 38, 53]) were divided in four groups: Mapuche CT (Map-CT, n = 14) or control group (Map-CG, n = 44), and European CT (Eur-CT, n = 14) or control group (Eur-CG, n = 23). The following endpoints were analyzed at baseline and after 12 weeks: anthropometric (body mass, body mass index, waist circumference), body composition (fat mass, muscle mass, lean mass), cardiovascular (systolic [SBP]/diastolic [DBP] blood pressure), metabolic (blood fasting glucose and total cholesterol), and muscle strength (handgrip of dominant/non-dominant arm). There were significant positive changes in body mass, body fat, and muscle mass (P < 0.0001) in both Map-CT and Eur-CT groups, whereas waist circumference was decreased significantly only in the Eur-CT group (P < 0.0001). Both Map-CT and Eur-CT groups showed decreased levels of fasting glucose (P < 0.05) and total cholesterol after the intervention (P < 0.0001). Also, both Map-CT (P < 0.05) and Eur-CT (P = 0.01) groups showed a lowered SBP. Finally, significant increases were observed after training in handgrip strength (dominant arm) in Map-CT and Eur-CT groups (both P < 0.0001). CT led to similar improvements in cardiometabolic risk factors for metabolic syndrome development in Mapuche and European participants, with additional improvements in other anthropometric, body composition, cardiovascular, metabolic, and muscle strength parameters related to the prevention of metabolic syndrome. These results suggest future more complex studies.

Diphtheria Outbreak in Amerindian Communities, Wonken, Venezuela, 2016-2017.

In February 2017, a diphtheria outbreak occurred among Amerindians of the Pemón ethnic group in Wonken, Venezuela. A field investigation revealed ≈10 cases; clinical presentation did not include cutaneous or neurologic signs or symptoms. To prevent future outbreaks in Venezuela, Amerindian communities need better access to vaccination and healthcare.

Determination of hepatitis B, C and D prevalence among urban and Amerindian populations from the Eastern Brazilian Amazon: a cross sectional study.

BACKGROUND: This study was conducted to determine the prevalence of HBV, HCV, and HDV in urban populations and Amerindians living in the state of Tocantins (Eastern Amazon). METHODS: A total of 948 individuals were recruited in Tocantinopolis city (Tocantins state) of whom 603 were Amerindians (from 6 tribes) and 345 were non-Amerindians (6 urban areas of Tocantinópolis city). Anti-HCV, HBsAg, anti-HBc, anti-HBs, anti-HBc IgM, anti-HBe, HBeAg, and anti-delta antibodies were determined using enzyme immunoassay. RESULTS: HBV cleared infection (both anti-HBc/anti-HBs+), chronic inactive/immune controlled HBV infection (anti-HBc + only), previous HBV vaccination (anti-HBs + only), active HBV infection (HBsAg+), individuals susceptible to HBV, and anti-HCV reactivity were found in 12.9, 1.8, 27.2, 0.5, 57.7, 1.2% in Amerindians and 12.1, 2.0, 37.1, 0.3, 55.4, 0.3% in non-Amerindians respectively. Out of 139 anti-HBc reactive individuals, 70 were anti-HBe reactive and none presented HBeAg or anti-HBc IgM. Anti-HBc prevalence was associated to older age (p < 0.0001). Overall anti-Delta prevalence was 0.3% and regarding anti-HBc reactive individuals, anti-delta prevalence was 3.4 and 0% in Amerindians and non-Amerindians respectively. CONCLUSIONS: Overall low prevalence of HBV and HCV infection was found in the populations studied, but high HBV and HCV prevalence was observed in Amerindians compared to non-Amerindians suggesting that these individuals have a higher likelihood of acquiring to these infections. Anti-delta antibodies were found among Amerindians from Eastern Amazon suggesting a risk for this population. Of note is that nearly half of Amerindians had no anti-HBs, indicating a need for HBV vaccination campaigns in this population.

Genetic variability among Mexican Mestizo and Amerindian populations based on three ABCB1 polymorphisms.

The most widely studied polymorphisms of the ABCB1 gene are rs1128503 (c.1236C>T), rs2032582 (c.2677G>T/A), and rs1045642 (c.3435C>T). Although variation in ABCB1 allele frequencies among Mexican Mestizos (admixed) from different regions has been observed, Mexican Amerindians have been poorly studied. We aimed to describe the genetic variability of these three ABCB1 polymorphisms in a total sample of 273 Mexican volunteers that included Mestizos from the state of Yucatán, and Amerindians from seven populations (Tarahumara, Mayo, Huichol, Purépecha, Nahua, Tojolabal, and Maya). Genotypes were determined by means of Taq Man probes (qPCR). Genotype distribution was in Hardy-Weinberg equilibrium for all three ABCB1polymorphisms in the eight Mexican populations analyzed. For c.1236C>T and c.3435C>T, the heterozygous C/T was the most frequent genotype in the majority of the studied Mexican populations (range 30.8-65.4%), while heterozygous G/T was the most common genotype for c.2677G>T/A (range 25.9-51.2%), mainly followed by G/G (range 3.2-47.1%) and T/T (range 7.0-35.5%). 12 haplotypes were estimated from the three ABCB1 polymorphisms analyzed, with TTT the most frequent haplotype (mean, 37.0%). Genetic differentiation was demonstrated among the studied Mexican populations (Fst p value < 0.0001), which could imply a diverse drug response or a risk for adverse drug reactions to ABCB1 substrates. Although differences among Amerindians are probably due to genetic drift effects, for Mestizos this could imply variation in admixture composition. In conclusion, interpopulation variability in the observed frequencies of ABCB1 polymorphisms among Mexican Mestizos and Amerindians allow predicting diverse drug responses to ABCB1 substrates in these populations.

Descriptive epidemiology of suicide attempts and suicide in the remote villages of French Guiana.

OBJECTIVE: The overall rate of suicide in French Guiana is estimated at 6 per 100,000, a rate that is lower than in mainland France. Given the frequent reports of suicide in Amerindian communities, our hypothesis was that this figure fails to capture a more contrasted reality. Our objective was to refine estimates and determine suicide rates in remote villages of French Guiana. METHODS: We included patients for whom a suicide attempt or suicide was mentioned in medical records. The Health centers were grouped into two zones according to geographical remoteness. RESULTS: The highest suicide rates observed in the remote Amerindian villages of Camopi and Trois Sauts were, respectively, 118 and 78/100,000. The median age at the time of suicide was significantly younger in remote zones [23 years (95% CI 21.59-25.06)] than in non-remote zones-[27 years (95% CI 24.47-29.31)]. The most frequent methods were hanging (78%) and intoxication (22%). CONCLUSIONS: The suicide rate in remote areas in French Guiana was eight times higher than in France. The suicide of young people in remote areas in French Guiana and specifically in Amerindian villages must be better understood and prevented with contextualized and adapted care.

The relationship between the neck circumference and the carotid intima-media thickness in Amerindians. Potential links to health risks?

The carotid intima media thickness (cIMT) is a predictor of cardiovascular events. The neck circumference (NC) has been investigated as a risk factor for increased cIMT with contradictory results. This study assessed the relationship between NC and cIMT in Atahualpa residents aged ≥40 years who had sonographic examination of carotid arteries (n = 590). We also discussed on potential pathogenetic mechanisms underlying this association. Participants belonged to the Native Ecuadorian (Amerindians) ethnic group. Non-parametric regression models were used to assess the aforementioned relationship, after adjusting for relevant confounders. The mean age of participants was 60.9 ± 12.7 years (58% women). The mean value of the cIMT was 0.85 ± 0.19 mm. The mean NC was 35.8 ± 34 cm. The NC was normally distributed, but the cIMT was not. Mean values of NC and cIMT were significantly greater in men than in women. Non-parametric models showed significant differences in median cIMT values according to quartiles of NC. Predictive cIMT margins increased by quartiles of NC, significantly among individuals in the 1st quartile as compared to the 3rd quartile. In this population of Amerindians, smaller NC is associated with lower values of cIMT. The pattern of this association is different in men than in women. Sex-related differences in cervical fat tissue distribution probably accounted for such differences.

Low prevalence of atrial fibrillation in Amerindians: a population-based study in frequent fish consumers living in rural coastal Ecuador (The Atahualpa Project).

BACKGROUND: Information on the burden of atrial fibrillation (AF) in rural areas of developing countries is limited. Here, we aimed to assess AF prevalence in community-dwelling older adults living in rural Ecuador. METHODS: Atahualpa residents aged ≥60 years (mean age 70.5 ± 8.1 years) underwent 24-h Holter monitoring. Participants belong to the Amerindian ethnic group. The mean height in the study population was 147.9 ± 8.9 cm. Oily fish was a major source of food (mean intake: 8 ± 4 servings/week). RESULTS: Seven of 298 participants (2.3%) had AF. Persons with AF were older than those without (p = 0.051), but there were no differences in cardiovascular risk factors across groups. None of the seven AF cases had been detected in routine 12-lead ECGs taken at enrollment. CONCLUSIONS: Prevalence of AF in older Amerindians living in rural Ecuador is low. Both, racially-determined short stature and frequent dietary oily fish intake might explain the low prevalence of AF in this rural setting.

Multiple Sclerosis in Latin Americans: Genetic Aspects.

Latin Americans (LA) are a heterogeneous, multiethnic group of individuals who inhabit the continental countries in Latin America (LATAM), Caribbean islands and constitute the largest ethnic minority in the USA. Commonly used terminology and ethno racial classifications to define these groups may not be accurate. Risk for multiple sclerosis (MS) among LA is generally low to medium but frequencies are increasing in the American hemisphere. Genome-Wide Association Studies (GWAS) in LA show diverse variants and genetic proportions among Mestizos, the most representative ethnic population, who themselves are the product of centuries of interracial mixing between Native Americans (or Amerindians), White Caucasian Europeans, and Black Africans. Genetic distribution diversity appears to be related to migratory and historical and socio-political factors in LATAM. Epidemiologic studies show an extremely low prevalence of MS among non-mixed Amerindians; this has been attributed to protective ancestral Asian genetics and possibly, environmental factors. Mestizos and biracial LA of African ancestry have more susceptibility to MS apparently due to the historical introduction of the European HLA-DRB1*1501 gene. Contribution from HLA typing, GWAS, and ancestry informative markers (AIMs) has been determinant in the current LA genetic understanding but more regional studies are needed. The relationship between genetics and disease regional distribution is emphasized.

High Prevalence of ITPA Alleles Associated with Ribavirin-Induced Hemolytic Anemia Among Mexican Population.

BACKGROUND: The prevalence of two functional polymorphisms (rs1127354 and rs7270101) of the inosine triphosphatase (ITPA) gene associated with ribavirin-induced hemolytic anemia (RIHA) during antiviral therapy for hepatitis C virus (HCV) infection varies by ethnicity. In Mexico, the distribution of these polymorphisms among Native Amerindians (NA) and admixed population (Mestizos) is unknown. This study aimed to determine the prevalence of the ITPA polymorphisms among healthy NA and Mestizos, as well as in HCV patients from West Mexico. MATERIAL AND METHODS: In a cross-sectional study, 600 unrelated subjects (322 Mestizos, 100 NA, and 178 treatment-naïve, HCV-infected Mestizos patients) were enrolled. A medical history was registered. ITPA genotype was determined by Real-Time PCR. Fst-values and genetic relatedness between study and reference populations were assessed. RESULTS: The frequency of the risk genotypes rs1127354CC and rs7270101AA was higher among NA (98-100%) than in Mestizos (87-92.9%), (p &lt; 0.05). The NA presented the highest prevalence of the rs1127354CC genotype reported worldwide. The Fst-values revealed a genetic relatedness among Mexican NA, South Americans and African populations (p &gt; 0.05). The frequency of the predicted risk for RIHA was higher among NA (98%) than in Mestizos (80.5%) and HCV-infected patients (81.5%) (p &lt; 0 .01). The CC/AA alleles were associated with lower values of total bilirubin, aspartate/alanine aminotransferases, and aspartate-to-platelet-ratio-index score among HCV-patients. CONCLUSION: A high prevalence of the ITPA polymorphisms associated with RIHA was found in Mexican NA. These polymorphisms could be a useful tool for evaluating potential adverse effects and the risk or benefit of antiviral therapy in Mexicans and other admixed populations.

Health care importance of Treponema pallidum, Chagas' disease and Human immunodeficiency virus 1 among Amerindians of Argentina: an observational study.

The objective of this study was to estimate the prevalence of Treponema pallidum, Trypanosoma cruzi and Human immunodeficiency virus 1 (HIV-1) in five Amerindian populations of Argentina. A retrospective study was conducted among 857 Amerindian populations (112 Kollas, 298 Mbyá-guaraníes, 79 Sagua Huarpes, 368 Wichis) from 2007 to 2010. Screening and confirmation of T. pallidum, T. cruzi and HIV-1 were performed. T. pallidum and T. cruzi infections were detected in all communities with an overall prevalence rate of 4.2% and 16.8%, respectively. Although HIV was not detected, syphilis and Chagas' disease represent a challenge for the health care system and the reinforcement of public health strategies is necessary considering the socioeconomic isolation of these populations.