Another Benefit of a Healthy Lifestyle: Lower Risk of SCD

80% of SCD in Women Could Be Avoided With All-Around Healthy Lifestyle

July 07, 2011

July 5, 2011 (Boston, MA) — A new study shows that up to 80% of sudden cardiac death (SCD) could be attributable to unhealthy lifestyle practices, at least among women [1]. The research illustrates that those who adhered to four healthy lifestyle practices--not smoking, body-mass index (BMI) <25 kg/m2,, exercising 30 min/day or longer, and eating a Mediterranean diet--had a 92% lower risk of SCD than women who did not.

The findings are very important, Dr Stephanie E Chiuve (Harvard Medical School, Boston, MA), lead author of the new study, told heartwire . "Most prevention efforts are focused on identifying patients at very high risk of SCD--who account for only 25% to 30% of SCD--and implanting ICDs [implantable cardioverter-defibrillators]. But for most people, sudden cardiac arrest is the first manifestation of coronary disease--the majority of these events occur among people who are apparently healthy and would not be identified as high risk in a clinical setting--and there is a very low rate of survival, only about 7%. We wanted to come up with prevention strategies that can be applied to the general population, rather than focused on high-risk patients."

Although she says it is known that smoking, obesity, not exercising, and poor diet "are risk factors for SCD, nobody's really looked at the combination of these risk factors to see truly the burden that may be explained through unhealthy behaviors.

"Basically, the implication is that adherence to a healthy lifestyle that has been associated with lower risk of other chronic diseases may also be an effective strategy for the primary prevention of SCD among women and may prevent more than 80% of SCDs. This is another benefit for following a healthy lifestyle," she explained.

Not enough emphasis on healthy lifestyle in SCD field

Chiuve and colleagues estimated the burden of SCD that may be attributable to adverse lifestyle factors in a prospective cohort of 81 722 women from the US Nurse's Health Study, followed from 1984 to 2010. Lifestyle factors were assessed using questionnaires every two to four years. A low-risk lifestyle was defined as not smoking, BMI <25 kg/m2, exercise duration of 30 min/day or longer, and top 40% of the alternate Mediterranean diet score, which emphasizes high intake of vegetables, nuts, legumes, whole grains, and fish and moderate intake of alcohol.

The main outcome was sudden cardiac death, defined as death occurring one hour after symptom onset without evidence of circulatory collapse. There were 321 cases of SCD during 26 years of follow-up. Women were a mean age of 72 at the time of the SCD event.

All four low-risk lifestyle factors were significantly and independently associated with a lower risk of SCD. The multivariable relative risk of SCD was 0.08 for those with all four low-risk lifestyle factors, 0.33 for those with three, 0.41 for those with two and 0.54 for those with one, compared with women who had none.

"Most of the primary-prevention strategy really is trying to find people at high risk, people who have low EF, or had sudden cardiac arrest [SCA] before, or history of SCA in the family, or previous coronary disease, but only a third of SCD actually occurs within this population," Chiuve explained.

"In the field of SCD there's really not a lot of attention put on general healthy lifestyles or any focus on lifestyle strategies to prevent SCD, and I think that's one of the important points of this study. If all women adhered to an all-around healthy lifestyle, this would help cut the risk of sudden cardiac death significantly," she concluded.

Coauthor Dr Teresa T Fung (Harvard Medical School) has received financial compensation for her work as a member of the nutrition advisory board for Uno's restaurant. The other authors report no conflicts of interest.


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