July 6, 2011

Living Healthy Lowers Risk Of Sudden Cardiac Death

Researchers have found that women who stay fit, eat healthier, do not smoke, and maintain a healthy weight may have a greater chance of avoiding risk of sudden cardiac death (SCD).

The study, funded by the National Institutes of Health and American Heart Association, and published in the Journal of the American Medical Association, found that each positive lifestyle choice was linked to the lower risk of sudden cardiac death, and when all factors were added together, the chance of SCD dropped 92 percent.

"The more you adhere to this healthy lifestyle, the better you are in terms of your risk of sudden cardiac death," lead author of the study, Dr. Stephanie Chiuve of Brigham and Women's Hospital in Boston, told Reuters Health.

The study, however, did not look at how long women adhered to each of the healthier lifestyle choices, nor was it able to prove that healthy living is actually responsible for the drop in SCD risk.

"Sudden cardiac death [defined as death occurring within one hour after symptom onset without evidence of circulatory collapse] accounts for more than half of all cardiac deaths, with an incidence of approximately 250,000 to 310,000 cases annually in the United States," the authors wrote as background information in the study. The authors also noted that no other studies have examined the combination of multiple lifestyle factors and the risk of SCD.

Unlike a heart attack, which is caused by a blood vessel blockage, sudden cardiac death is related to malfunctioning of the electrical rhythm of the heart.

For the new study, Chiuve and her colleagues analyzed results from the Nurses' Health Study, in which more than 81,000 women periodically answered surveys about their health and lifestyle.

During the 26 year period of the study, 321 women suffered SCD at an average age of 72.

"We know that a healthy lifestyle is very important to prevent many chronic diseases, including heart disease, diabetes, and certain cancers. So we weren't surprised but we were impressed at how strongly associated these lifestyle factors were for preventing sudden cardiac death," Chiuve told WebMD.

Suzanne Steinbaum, MD, director of women and heart disease at Lenox Hill Hospital in New York, calls the new findings "significant" and "empowering."

If "you never smoke, exercise 30 minutes a day, don't gain too much weight, and eat a Mediterranean-style diet, you will reduce your risk for sudden cardiac death, and your risk for diabetes, high blood pressure, and high cholesterol, too," Steinbaum told WebMD.

Women who ate a diet similar to the Mediterranean diet, which has a high proportion of vegetables, fruits, nuts, omega-3 fats, and fish, along with moderate amounts of alcohol and small amounts of red meat, had a 40 percent lower risk of SCD than women whose diets least resembled the Mediterranean diet.

"Take baby steps," said Steinbaum. "Don't try to lose 30 pounds. Just eat healthier and start by exercising for five minutes a day and build up to 30 minutes on most days."

Weight was tied to a similar effect on risk. Normal-weight women were 56 percent less likely to suffer SCD compared to obese women. Exercise was also linked to a smaller chance of SCD, and the more women exercised, the smaller the risk. Smoking was the biggest factor. Women who never smoked were 75 percent less likely to suffer SCD than women who smoked at least 25 cigarettes per day.

The researchers concluded that 81 percent of the cases of SCD were due to unhealthy lifestyle.

Chiuve told Reuters Health that the results are important for understanding who is at risk for SCD. Most people that are at high risk are so because of other health problems, such as having has a heart attack in the past.

"But with sudden cardiac death, the majority (of cases) occur in the general population," she told Reuters reporter Kerry Grens. "Lifestyle is not something that's generally focused on in sudden cardiac death research."

SCD is a rare event, but Chiuve noted that lifestyle-based efforts to prevent it can also impact the risks for more common health problems, such as diabetes and stroke.

"The primary prevention of SCD remains a major public health challenge because most SCD occurs among individuals not identified as high risk," the authors wrote. "In this cohort of female nurses, adherence to an overall healthy lifestyle was associated with a lower risk of SCD and may be an effective strategy for the prevention of SCD."


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