Lifestyle culprit in increase in cardiovascular disease

6 min read

Diet spreads problem throughout the world

Despite the perception that cardiovascular disease is a problem of industrialized countries, it is the leading cause of death everywhere except Africa, where it is eclipsed by the raging AIDS epidemic, experts gathered at Harvard Medical School (HMS) said Wednesday.

Authorities on cardiovascular disease from around the world attended a daylong conference sponsored by the Harvard Initiative for Global Health’s Chronic and Cardiovascular Diseases Working Group. Called “Cardiovascular Disease in Developing Countries – Moving Forward,” the event featured discussions on a wide range of heart-related issues, including diet, salt intake, tobacco use, and blood pressure, and updates on the situations in specific places, such as Poland, India, and Africa.

Harvard Provost Steven E. Hyman made opening remarks at the event, saying he hoped it would not just foster an exchange of information but also create working relationships that would address the problem. Hyman said that though anyone visiting the developing world is struck by the burden that infectious diseases still put on the population, the conference was a sign that the international health community also understands that noncommunicable diseases, such as diabetes and cardiovascular disease, are also a problem there.

“I think the field of global health has reached a new stage of maturity. In some sense this conference is a symbol of that maturity,” Hyman said.

Conference organizer Thomas Gaziano, assistant professor of medicine at HMS,  an adjunct assistant professor of health policy and management at the Harvard School of Public Health‘s Center for Health Decision Science, and a physician at Brigham and Women’s Hospital(BWH), said that though cardiovascular disease is the leading cause of death in the world outside Africa, there exist numerous opportunities to address the problem. He called the conference “a start” and said he envisions additional such gatherings in the future.

Speakers at the event addressed a variety of issues related to cardiovascular disease. Bruce Neal, professor of medicine at the University of Sydney, senior director of the George Institute for International Health, and chair of the Australian Division of World Action on Salt and Health, said that reducing salt in people’s diets worldwide might be the most cost-effective way to improve heart health by lowering blood pressure.

With high blood pressure a leading risk factor for heart attack and stroke and excess salt intake a known factor in elevating blood pressure, Neal said a concerted campaign to reduce salt in foods could have an even larger effect on public health than anti-smoking campaigns. That’s because though tobacco is more harmful to any individual’s health, far more people are affected by excess salt in foods.

Neal said if no salt were added to people’s diets they would naturally take in 1 to 2 grams a day. In most countries, he said, the added salt consumption is five to 10 times higher than that. Salt intake has been shown to increase blood pressure immediately, but it also has a long-term effect, with each extra 6 grams of salt eaten per day resulting in an annual increase in average blood pressure as well.

In the industrialized world, the largest source of extra salt is processed foods, followed by salt added in cooking or at the table, and the salt naturally present in foods. Though people in the developing world get less salt from processed foods, almost everyone today eats too much salt, Neal said.

Neal said current programs to lower blood pressure are ineffective. He cited Australia’s $1 billion national program to lower high blood pressure as an example. The first problem, he said, is that the program is aimed at people with elevated blood pressure readings. Roughly half of people who experience blood pressure-related ailments do not have what would be considered high blood pressure, Neal said, meaning that the program misses half the problem from the start. From there, he said, the program estimates it reaches 47 percent of the people eligible. Of that proportion, just 40 percent are meeting their blood pressure target. All told, Neal said, just about one in 10 people who need to lower their blood pressure are doing so through the national program.

Neal suggested government intervention as a way to improve the situation, by lowering the salt content of processed foods. If people ate 3 grams less of salt per day, not only would there be an immediate lowering of the population’s blood pressure, but there would also be long-term health effects, because of the long-term effects of salt, that would accrue over time.

Reducing salt intake has several benefits over the use of high blood pressure drugs, Neal said, such as no side effects, lower cost, and greater health benefits for children. A 3 gram drop in salt intake, he said, would reduce stroke 15 percent and coronary heart disease 9 percent.

That initial investment would give you an initial fall, but you will continue to get health benefits for years or decades to come,” Neal said. “Salt reduction programs could be highly cost-effective in every region of the world.”

International health experts are still getting a grasp on the scope of the overall cardiovascular disease problem and current efforts to curb it. Dariush Mozaffarian, an HMS assistant professor in the Division of Cardiovascular Medicine at BWH and an assistant professor in the Department of Epidemiology at the HSPH, is working on the World Health Organization’s Global Burden of Disease Study. He said efforts are under way to get information from 21 different regions on diet and cardiovascular disease.

Preliminary data from the United States are not promising, however. Though there have been many advances in nutrition science in recent years, the preliminary data show that a “remarkably small” number of people are meeting the national guidelines for a healthy diet. Fewer than 40 percent are meeting guidelines on saturated fat consumption, less than a quarter are meeting guidelines on fish intake, and less than 20 percent are meeting guidelines on fruit, vegetable, nut, salt, and whole grain consumption.

“Diet is disastrous in this country; that’s why we have the obesity epidemic,” Mozaffarian said.