Big Midsection May Up Risk of Dying Suddenly

By Todd Neale, Senior Staff Writer, MedPage Today Published: May 10, 2012
Reviewed by Zalman S. Agus, MD; Emeritus Professor, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner

Action Points

• This study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
• Note that in this study, after multiple adjustments, the only measure of obesity that was associated with sudden cardiac death was waist-to-hip ratio.

BOSTON -- Carrying too much weight in the belly -- having an apple shape -- may increase the risk of sudden cardiac death, researchers found.
In a cohort study, the risk of sudden cardiac death increased along with waist-to-hip ratio (P=0.009 for trend), according to Selcuk Adabag, MD, of the University of Minnesota and the VA Medical Center in Minneapolis.
After accounting for numerous obesity-related comorbidities, however, other measures of obesity -- body mass index and waist circumference -- were not related to the risk of sudden cardiac death, Adabag reported at the Heart Rhythm Society meeting here.
Obesity "is a root cause of problems," he said in an interview. "People, particularly physicians, need to be paying attention to weight gain and should actively work on reducing weight."
The findings of the current study could be incorporated into the counseling that physicians give to patients, he said, although waist-to-hip ratio is not often measured in the clinic and the public is not as familiar with that index of obesity as it is with BMI.
Obesity has been associated with a higher risk of sudden cardiac death in both the Framingham Heart Study and the Nurses' Health Study, but the analysis by Adabag and colleagues took it a step further by examining three different measures of obesity -- BMI, waist circumference, and waist-to-hip ratio.
The researchers used data on 15,156 black and white participants from the Atherosclerosis Risk in Communities (ARIC) study, which enrolled individuals ages 45 to 64 at baseline in 1987 to 1989.
Over a mean follow-up of 12.6 years, there were 301 cases of sudden cardiac death, defined as a death that occurred within 1 hour of symptom onset when witnessed or within 24 hours of being seen alive when unwitnessed.
All three measures of obesity were significantly and positively associated with sudden cardiac death after adjustment for age, sex, race, study center, education level, smoking status, and a family history of coronary heart disease (P≤0.005 for all three trends).
But further adjustment for obesity-related comorbidities that could be involved in the relationships -- including diabetes, LDL cholesterol, hypertension, prevalent coronary heart disease, heart failure, and left ventricular hypertrophy -- left only waist-to-hip ratio as a significant predictor of sudden cardiac death.
For individuals in the top quintile of waist-to-hip ratio (0.97 and higher for women and 1.01 and higher for men), the risk of sudden cardiac death was a relative 40% greater (HR 1.40, 95% CI 0.94 to 2.11) compared with those in the lowest quintile (less than 0.82 for women and less than 0.92 for men).
Adabag said that it is unclear why waist-to-hip ratio appears to be more informative than waist circumference or BMI, but speculated that it could have to do with the inflammatory markers produced by abdominal fat. Those markers result in fibrosis in the heart muscle, which could ultimately lead to arrhythmias and sudden cardiac death, he said.
Future research will focus on examining these same relationships in older individuals (65 and older) from the Cardiovascular Health Study. Both that study and ARIC have blood samples from the participants, which will allow investigators to explore the link between inflammatory markers and the risk of sudden cardiac death.