"Sudden cardiac death (SCD) [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 write as background information in the study. The authors also note that no prior studies have examined the combination of multiple lifestyle factors and risk of SCD.
Using data collected as part of the Nurses' Health Study, Stephanie E. Chiuve, Sc.D., of Brigham and Women's Hospital and Harvard Medical School, Boston, and colleagues examined the association between a healthy lifestyle and risk of SCD. A total of 81,722 women who participated in the Nurses' Health Study from June 1984 to June 2010 were included in the study, and lifestyle factors were assessed via questionnaires every two to four years. A low-risk lifestyle was defined as not smoking, having a body mass index (BMI) of less than 25, exercise duration of 30 minutes/day or longer, and consuming a diet closely related to a Mediterranean-style diet (emphasizes high intake of vegetables, fruits, nuts, legumes, whole grains and fish, with moderate alcohol intake).
During the 26 years of follow-up, there were 321 cases of SCD among women (average age 72 years at the time of the SCD event) in the study. All four low-risk factors were significantly and independently associated with a lower risk of SCD. Not smoking, exercising and eating a healthy diet each were inversely associated with risk of SCD. BMI also was associated with the risk of SCD, with women having a BMI between 21 and 24.9 at lowest risk.
Women at low risk for all four lifestyle factors had a 92 percent lower risk of SCD when compared with women at low risk for none of the four lifestyle factors.
"The primary prevention of SCD remains a major public health challenge because most SCD occurs among individuals not identified as high risk," the authors write. "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."