The epidemiology of dermatomyositis in South Australia

Aim: To review the epidemiology of dermatomyositis (DM) in South Australia (SA) and to compare it with other Australian states and New Zealand (NZ). Methods: Muscle biopsy and hospital separation data for DM in SA, other Australian states, and NZ were determined. The role of environmental factors was investigated. Results: From 1990 to 2005, there were 21 cases of biopsy‐proven DM in SA (62% F, mean age 49.7 ± 18.4) and 99 cases of polymyositis (PM). Based on biopsy‐proven figures, the average incidence of DM per year in SA was 1.4 ± 1.2, and 6.6 ± 2.6 for PM. Since 1991, there were 221 and 441 total separations from SA hospitals with principal diagnoses of DM and PM, respectively. The ratio DM/DM + PM is thought to correlate with solar irradiance, and within Australia, SA had the lowest ratio (0.39, 95% CI 0.22–0.56), with the highest ratio seen in WA (0.67, 95% CI 0.53–0.81). This ratio did not correlate with latitude, duration of sunshine, cloud cover, relative humidity or total rainfall. Within SA, no correlation with socioeconomic status was seen. Australian data were similar to NZ, where the ratios were 0.34 and 0.3 for North and South Islands, respectively. As separation data reflect total hospital visits, we also ascertained individual patient separations from SA hospitals (1997 to July 2005) and found a similar ratio of DM/DM + PM (0.38 ± 0.08). Conclusions: The proportion of inflammatory myositis which is DM varies nationwide, with a consistent ratio seen in SA (33–38%). Geoclimatic variables do not appear to influence DM/PM disease expression in Australia.     

Changing epidemiology of hepatocellular carcinoma in South America: A report from the South American liver research network

Introduction and objectivesMost epidemiological data on hepatocellular carcinoma (HCC) originate from resource-rich countries. We have previously described the epidemiology of HCC in South America through the South American Liver Research Network. Here, we provide an update on the changing epidemiology of HCC in the continent seven years since that report.Materials and methodsWe evaluated all cases of HCC diagnosed between 2019 to 2021 in centers from six countries in South America. A templated, retrospective chart review of patient characteristics at the time of HCC diagnosis, including basic demographic, clinical and laboratory data, was completed. Diagnosis of HCC was made radiologically or histologically for all cases via institutional standards.ResultsCenters contributed to a total of 339 HCC cases. Peru accounted for 37% (n=125) of patients; Brazil 16% (n=57); Chile 15% (n=51); Colombia 14% (n=48); Argentina 9% (n=29); and Ecuador 9% (n=29). The median age at HCC diagnosis was 67 years (IQR 59-73) and 61% were male. The most common risk factor was nonalcoholic fatty liver disease (NAFLD, 37%), followed by hepatitis C (17%), alcohol use disorder (11%) and hepatitis B (12%). The majority of HCCs occurred in the setting of cirrhosis (80%). HBV-related HCC occurred at a younger age compared to other causes, with a median age of 46 years (IQR 36-64).ConclusionWe report dramatic changes in the epidemiology of HCC in South America over the last decade, with a substantial increase in NAFLD-related HCC. HBV-related HCC still occurs at a much younger age when compared to other causes.     

Trends in hypertension epidemiology in India

Cardiovascular diseases caused 2.3 million deaths in India in the year 1990; this is projected to double by the year 2020. Hypertension is directly responsible for 57% of all stroke deaths and 24% of all coronary heart disease deaths in India. Indian urban population studies in the mid-1950s used older WHO guidelines for diagnosis (BP > or =160 and/or 95 mmHg) and reported hypertension prevalence of 1.2-4.0%. Subsequent studies report steadily increasing prevalence from 5% in 1960s to 12-15% in 1990s. Hypertension prevalence is lower in the rural Indian population, although there has been a steady increase over time here as well. Recent studies using revised criteria (BP > or =140 and/or 90 mmHg) have shown a high prevalence of hypertension among urban adults: men 30%, women 33% in Jaipur (1995), men 44%, women 45% in Mumbai (1999), men 31%, women 36% in Thiruvananthapuram (2000), 14% in Chennai (2001), and men 36%, women 37% in Jaipur (2002). Among the rural populations, hypertension prevalence is men 24%, women 17% in Rajasthan (1994). Hypertension diagnosed by multiple examinations has been reported in 27% male and 28% female executives in Mumbai (2000) and 4.5% rural subjects in Haryana (1999). There is a strong correlation between changing lifestyle factors and increase in hypertension in India. The nature of genetic contribution and gene-environment interaction in accelerating the hypertension epidemic in India needs more studies. Pooling of epidemiological studies shows that hypertension is present in 25% urban and 10% rural subjects in India. At an underestimate, there are 31.5 million hypertensives in rural and 34 million in urban populations. A total of 70% of these would be Stage I hypertension (systolic BP 140-159 and/or diastolic BP 90-99 mmHg). Recent reports show that borderline hypertension (systolic BP 130-139 and/or diastolic BP 85-89 mmHg) and Stage I hypertension carry a significant cardiovascular risk and there is a need to reduce this blood pressure. Population-based cost-effective hypertension control strategies should be developed.     

Heart Failure in South America

Continued assessment of temporal trends in mortality and epidemiology of specific heart failure in South America is needed to provide a scientific basis for rational allocation of the limited health care resources, and strategies to reduce risk and predict the future burden of heart failure. The epidemiology of heart failure in South America was reviewed. Heart failure is the main cause of hospitalization based on available data from approximately 50% of the South American population. The main etiologies of heart failure are ischemic, idiopathic dilated cardiomyopathy, valvular, hypertensive and chagasic etiologies. In endemic areas, Chagas heart disease may be responsible by 41% of the HF cases. Also, heart failure presents high mortality especially in patients with Chagas etiology. Heart failure and etiologies associated with heart failure may be responsible for 6.3% of causes of deaths. Rheumatic fever is the leading cause of valvular heart disease. However, a tendency to reduction of HF mortality due to Chagas heart disease from 1985 to 2006, and reduction in mortality due to HF from 1999 to 2005 were observed in selected states in Brazil. The findings have important public health implications because the allocation of health care resources, and strategies to reduce risk of heart failure should also consider the control of neglected Chagas disease and rheumatic fever in South American countries.     

The molecular epidemiology of HIV-1 in South and East Asia

Foremost amongst human pathogens, the human immunodeficiency virus (HIV) exhibits a great genetic variability. The resultant fluidity of HIV enzymatic proteins allows them to remain functional whilst simultaneously evading immune surrveillance and antiretroviral therapy. This very variability, however, has been turned to powerful advantage in the study of the movement and evolution of HIV strains within and between human populations. Molecular analyses that estimate the relatedness between viral isolates, conducted in tandem with epidemiological studies, provide a new clarity of insight into the modes and routes of HIV transmission and epidemic spread. In this paper the principles underlying the molecular study of HIV and the achievements of this new field of epidemiology in southern and eastern Asia are reviewed.     

Classification and epidemiology of pulmonary hypertension

Pulmonary hypertension is a complex disease that can be idiopathic, familial, or associated with a wide range of disease processes. This article outlines the classification of primary pulmonary hypertension and discusses the various types of the disease.     

Genetic epidemiology of essential hypertension.

This review article is intended to introduce the uninitiated clinician to the basic concepts, aims and early findings of the genetic epidemiology of hypertension. It separates the rare monogenic 'Mendelian' hypertensive disorders from the vast majority of patients with essential hypertension, which is a complex, polygenic, multifactorial disorder resulting from interaction of several genes with each other and with the environment. It highlights some clinical strategies used to enhance searches for 'candidates genes', such as subgrouping of populations into relatively homogenous groups or 'intermediate phenotypes' according to presumably heritable anthropometric, clinical or biochemical characteristics; and some applications of genetic epidemiologic techniques, such as linkage and association studies of certain gene polymorphisms with hypertension using affected sibling pairs and large sibships or wide genomic screens comparing affected and unaffected populations. Although so far there is no genotypic variation proven to be causally related to essential hypertension, its intermediate phenotypes or any of its complications, it is hoped that new, more efficient methods of genetic analysis will yield clinically meaningful information.     

Hepatitis E virus in South America: The current scenario

Hepatitis E virus (HEV) is one of the most frequent causes of acute viral hepatitis of enteric transmission worldwide. In South America the overall epidemiology has been little studied, and the burden of the disease remains largely unknown. A research of all scientific articles about HEV circulation in South America until November 2017 was carried out. Human seroprevalences of HEV varied according to the studied population: blood donors presented prevalence rates ranging from 1.8% to 9.8%, while reports from HIV‐infected individuals, transplant recipients and patients on hemodialysis showed higher prevalence rates. Only 2 cases of chronic hepatitis in solid‐organ transplant patients from Argentina and Brazil have been described. Detection of HEV in the swine population is widely prevalent in the region. Anti‐HEV antibodies have also been recently documented in wild boars from Uruguay. Although scarce, studies focused on environmental and food HEV detection have shown viral presence in these kind of samples, highlighting possible transmission sources of HEV in the continent. HEV genotype 3 was the most frequently detected in the region, with HEV genotype 1 detected only in Venezuela and Uruguay. HEV is widely distributed throughout South America, producing sporadic cases of acute hepatitis, but as a possible agent of chronic hepatitis. Finding the virus in humans, animals, environmental samples and food, show that it can be transmitted through many sources, alerting local governments and health systems to improve diagnosis and for the implementation of preventive measures.     

Feline immunodeficiency virus in South America

The rapid emergence of AIDS in humans during the period between 1980 and 2000 has led to extensive efforts to understand more fully similar etiologic agents of chronic and progressive acquired immunodeficiency disease in several mammalian species. Lentiviruses that have gene sequence homology with human immunodeficiency virus (HIV) have been found in different species (including sheep, goats, horses, cattle, cats, and several Old World monkey species). Lentiviruses, comprising a genus of the Retroviridae family, cause persistent infection that can lead to varying degrees of morbidity and mortality depending on the virus and the host species involved. Feline immunodeficiency virus (FIV) causes an immune system disease in domestic cats (Felis catus) involving depletion of the CD4+ population of T lymphocytes, increased susceptibility to opportunistic infections, and sometimes death. Viruses related to domestic cat FIV occur also in a variety of nondomestic felids. This is a brief overview of the current state of knowledge of this large and ancient group of viruses (FIVs) in South America.