Latin Americans can reduce heart attack risk by lifestyle changes
DALLAS , March 6 – The three major risk factors for heart attacks among Latin Americans could be reduced through lifestyle changes, according to a study published in Circulation: Journal of the American Heart Association in a special Latin American-themed issue called Heart Disease in Latin America .
"Knowledge of the peculiarities of heart disease and risks factors in Latin American countries, as presented in this issue of Circulation , contributes to the general understanding of the causes, methods, procedures and processes of cardiovascular disease ," s aid Edgardo Escobar, M.D., editor of the Latin American-themed issue and professor of medicine at the University of Chile in Santiago , Chile
Abdominal obesity, abnormal lipids and smoking account for 77.6 percent of the heart attack risks according to the largest-ever study of such risks in Latin America .
“Interventions to encourage lifestyle changes that target those risks could have a large impact on heart attacks in the region,” said Fernando Lanas, M. D ., M.Sc., lead author of one study and professor of medicine at the Universidad de la Frontera in Temuco , Chile .
Heart disease is the leading cause of death worldwide and accounts for more than a fourth of all deaths in Latin America . The analysis was part of INTERHEART, an international case-control study to assess the impact of well-established and emerging heart attack risk factors in various regions of the world.
Researchers evaluated 1,237 patients admitted with a first heart attack to a medical facility in Argentina , Brazil , Colombia , Chile , Guatemala and Mexico . They compared and matched patients (74.9 percent men, average age 59; and 25.1 percent women, average age 64.4) for gender and age to 1,888 people in a control group.
Those in the control group had no history of heart disease or chest pain. Some were treated at the same hospital for a condition unrelated to heart disease, while others were the relatives of patients without heart disease.
Participants answered questions about smoking, high blood pressure, diabetes, diet, physical activity and psychosocial factors. Researchers took standard physical measurements, including waist-to-hip ratio, an indication of the amount of fat in the abdomen.
They drew blood to measure the ratio of Apolipoprotein (Apo) B — a protein associated with LDL, or “bad” cholesterol — to ApoA1, a protein associated with HDL, or “good” cholesterol.
In the INTERHEART studies, a high ApoB/ApoA1 ratio has been found to be an important risk factor for heart disease. It can be a better predictor of heart disease than cholesterol levels because patients do not need to fast for the lipid testing and it includes all “bad cholesterol”.
The Latin American study found that 10 risk factors combined are responsible of 88 percent of the heart attacks in Latin America . Six individual factors more than doubled the risk of heart attack:
• Persistent psychological stress (odds ratio 2.81)
• History of high blood pressure (odds ratio 2.81)
• History of diabetes (odds ratio 2.59)
• Current smoking (odds ratio 2.31)
• Waist-to-hip ratio in upper third of participants compared with those in lower third (odds ratio 2.49)
• ApoB/ApoA1 ratio in upper third of participants compared with lower third (odds ratio 2.31).
Two factors — exercising regularly (odds ratio .67) and eating fruits and vegetables every day (odds ratio .63) — significantly lowered the risk of heart attack. Researchers also studied alcohol (odds ratio 1.05) and depression (odds ratio 1.17), but they were not associated with heart attack risk.
Researchers used population-attributable risk (PAR) to make their calculations, which considers how common a factor is and how much it boosts risks. It represents the proportion of heart attacks due to a risk factor.
PAR was reduced 75 percent in those who did not smoke, exercised regularly, and ate fruits and vegetables every day.
Risk factors were similar in the various Latin American countries studied, with most of the heart attack risk explained by tobacco use, abnormal lipids, abdominal obesity and high blood pressure.
Latin America differed from other regions studied in INTERHEART by having a larger proportion of heart attack risk due to high blood pressure, abdominal fat and permanent stress. A protective effect of alcohol consumption was found in other INTERHEART regions, but not in Latin America .
“Compared with other areas of the world studied in INTERHEART, we were surprised to find how much higher the PAR was for abdominal obesity and stress,” Lanas said.
However, he cautioned that, following a heart attack, patients may be more likely to report stress, potentially leading to overestimating stress as a risk factor.
“Given that all these factors are modifiable, the INTERHEART Latin American study provides a scientific basis to develop preventive strategies that are practical and generally similar in all countries in the entire region,” Lanas said.
An accompanying editorial by Sidney C. Smith Jr., M.D., a former American Heart Association president, said the study raises particular concern about abdominal obesity because it can significantly increase the risk of cardiovascular disease and diabetes. He cited a shift in diet and purchasing habits.
“In Latin American countries and many others with developing economies, there has been a rapid shift in diet to increased consumption of high energy-dense foods and caloric beverages, animal-source foods and caloric sweeteners added to many other foods. . . . Importantly, the availability and greater consumption of caloric beverages is not associated with a reduction in food intake,” wrote Smith, a professor of medicine, and director of the Center for Cardiovascular Science and Medicine at the University of North Carolina School of Medicine in Chapel Hill, N.C.
The results of the INTERHEART study and others in the themed issue “underline the need for major lifestyle and behavioral changes in Latin America if the growing toll of coronary heart disease is to be reversed,” Smith wrote.
Co-authors of the INTERHEART study are Álvaro Avezum, M. D ., Ph. D .; Leonelo Bautista, M. D ., D r.P.H.; Rafael D iaz, M. D .; Max Luna, M. D .; Shofiqul Islam, M.Sc. and Salim Yusuf, D .Phil.
The INTERHEART study was funded by the Canadian Institutes of Health Research, the Heart and Stroke Foundation of Ontario, the International Clinical Epidemiology Network (INCLEN), and unrestricted grants from several pharmaceutical companies, including major contributions from AstraZeneca, Novartis, Hoechst Marion Roussel (now Aventis), Knoll Pharmaceuticals (now Abbott), Bristol-Myers Squibb, King Pharma, and Sanofi-Sythelabo (now Sanofi Aventis), and by Universidad de la Frontera, Sociedad Chilena de Cardiología Filial Sur in Chile , Colciencias, Ministerio de Salud in Colombia and Liga Guatemalteca del Corazón in Guatemala .
Editor's Note: For more information about heart attack prevention, visit americanheart.org/heartattack.
Statements and conclusions of study authors published in the American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect association policy or position. The American Heart Association makes no representation or warranty as to their accuracy or reliability.
###NR07 – 1130 (Circ/Lanas)
Contact information : Dr. Escobar can be reached at 011 ( 56) 2 437 4900
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From the Heart Disease in Latin America issue ofCirculation: Journal of the American Heart Association
FOR RELEASE: 4 p.m. EST , March 5, 2007
Adaptation to high altitudes linked to highlanders' ancestry
More than 140 million people in the world live above 2,500 meters (8,202 feet) and Chronic Mountain Sickness (CMS) is a public health problem in the Andes and other mountainous regions in the world. CMS develops when the capacity for altitude adaptation is lost, which leads to moderate-to-severe pulmonary hypertension (abnormally elevated pressures in the lung arteries) and, ultimately, congestive heart failure. CMS symptoms are decreased exercise tolerance, sleep disorders, headache, dizziness, tinnitus, physical weakness, mental fatigue and sensations of tingling, pricking or numbness of the skin . CMS gradually disappears after people descend to a low altitude and reappears if they return to the higher altitude. Researchers analyzed studies from around the world going back at least four decades to review the physiology, pathology, pathogenesis and clinical features of the heart and lung circulation in healthy highlanders and patients with CMS. Shortly after birth, healthy highlanders' distal pulmonary arterial branches are remodeled, which is the main factor for their unusual heart and lung condition, researchers said. They also found evidence that the number of generations living at high altitude is a contributing determinant of the magnitude of pulmonary artery pressure (PAP) elevation. This factor explains higher PAP in a relatively new high altitude population of Leadville , Colo. , in contrast with normal PAP in Tibetan natives who have the oldest altitude ancestry in the world.
The heart and lung circulation in healthy highlanders has distinct features compared to that of people who live at sea level. Researchers concluded that “CMS is a public health problem in the Andean mountains and other mountainous regions around the world. Therefore, dissemination of preventive and therapeutic measures is essential.” Dante Penaloza, M.D., University Cayetano Heredia, Lima, Peru ; 011 51 1 372-5149
Researchers identify main predictors of death in people with chronic Chagas' disease
Chagas is a parasitic disease transmitted to people through the feces of infected bloodsucking insects and occasionally by blood transfusions and through food. Chagas' disease is a major cause of sickness and death in Latin America . Recent estimates from the World Health Organization indicate that 18 million people are chronically infected, with about 200,000 new cases occurring each year. Chagas' disease has two phases: acute and chronic. Both phases can be symptom-free or life-threatening. The acute phase lasts for the first few weeks or months of infection. It's usually unnoticed because it's symptom-free or exhibits only mild symptoms and signs that are not unique to Chagas' disease. S ymptoms can include fever, fatigue, body aches, headache, rash, loss of appetite, diarrhea and vomiting. During the chronic phase , the infection may remain silent for decades or even for life. However, some people develop cardiac or intestinal complications. Researchers reviewed studies from 1985 to 2006. Twelve studies met their criteria: eight clinic-based studies including 3,928 patients and four hospital-based studies including 349 patients. Researchers found impaired left ventricular ( LV ) function was the most common and consistent independent predictor of death in patients with Chagas' disease. New York Heart Association (NYHA) functional class of III and IV and cardiomegaly (enlarged heart) on the chest radiography were also independently associated with a higher risk of death. In more recent studies, a non-sustained ventricular tachycardia (NSVT) on a 24-hour Holter monitor also indicated increased risk. “Knowledge of these predictors can help to identify patients at different degrees of risk, facilitate and direct treatment choices and aid patient counseling,” researcher said. They also hoped their study would “improve the quality and relevance of future studies” on Chagas' disease.Anis Rassi Jr., M.D., Ph.D., Anis Rassi Hospital , Goiania , Brazil ; 011 55 62 3227 9105 or
See also “Pathogenesis of chronic Chagas' heart disease” for another review of studies to determine how Chagas' disease develops into Chagas' heart disease. Jose Antonio Marin-Neto, M.D., Ph.D.; 011 55 16 3602 2599
See also “Echocardiography in Chagas' heart disease” for a study that analyzed echocardiographic and Doppler tools for detecting early heart damage, risk assessment, prognosis, progression and management of patients with Chagas' disease. Harry Acquatella, M.D., Centro Medico in Caracas, Venezuela ; 011 58 212 552 1886 or
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