American Heart Association Announces Ways For Latin Americans To Reduce Risk Factors For Heart Attacks

DALLAS, – 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,” said 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.

Ischemic heart disease is the leading cause of death worldwide and accounts for more than a fourth of all deaths in Latin America, Lanas said. 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.

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 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., said the study raises particular concern about abdominal obesity because it can significantly increase the risk of cardiovascular disease and diabetes.

“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,” Smith wrote.

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.”

Co-authors of the INTERHEART study are Álvaro Avezum, M.D., Ph.D.; Leonelo Bautista, M.D., Dr.P.H.; Rafael Diaz, 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 www.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.


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