''Previous studies were suggesting that central obesity [people with apple-shaped obesity] was worse compared to general obesity," researcher Emanuele Di Angelantonio, MD, PhD, lecturer at the University of Cambridge, U.K. ''Actually, this study shows that the two [types of obesity] are the same in terms of cardiovascular risk."
"Obesity is an important driver for cardiovascular disease, whatever form it is," says Di Angelantonio.
The various measures used to assess obesity -- such as body-mass-index (BMI), waist circumference, and waist-to-hip ratio -- all perform similarly when used to assess cardiovascular risk, the researchers found.
Obesity and Heart Disease: Focusing on the Prediction Debate
Over the years, guidelines from national and international organizations such as the National Heart, Lung, and Blood Institute and the World Health Organization have recommended a variety of measures to predict a person's risk of cardiovascular disease.
These recommendations include the obesity measures such as body-mass-index (BMI), along with screening tests such as cholesterol, and taking into account other risk factors.
"There has been a lot of controversy" about which recommendation is best to predict a person's risk of cardiovascular disease, according to Di Angelantonio.
So Di Angelantonio and his colleagues from the Emerging Risk Factors Collaboration evaluated the medical records of 221,934 men and women in 17 countries who had participated in 58 studies.
70%, had data available on common risk factors such as diabetes history, smoking status, systolic blood pressure (the upper number), and cholesterol (total and HDL or "good" cholesterol).
The researchers objective was to analyze individual data and produce reliable estimates of the association of BMI, waist circumference, and waist-to-hip ratio with the onset of cardiovascular disease; including coronary heart disease, cardiovascular disease, or stroke.
Participants were, on average, 58 years old when the studies started and resided in Europe, North America, Australia, and Japan. Study participants were free of cardiovascular problems at the study start. Each was monitored for nearly a decade.
During the follow-up, there were 14,297 cardiovascular events.
The findings contradict the widely held idea that people with apple-shaped obesity are at higher risk than others for heart attack and stroke..
''Either BMI [which measures general obesity] or waist circumference or waist-to-hip ratio [a reflection of central obesity] have a similar association with the risk of cardiovascular disease," Di Angelantonio says..
The researchers found, too, that if information on blood pressure and cholesterol is available, along with information on risk factors such as diabetes, those are enough to predict cardiovascular disease risk. "You don't need to measure anything else," according to Di Angelantonio.
“The new research hopefully will lay to rest which obesity measure is best for predicting risk,” wrote Rachel Huxley, DPhil, associate professor at the University Of Minnesota School Of Public Health in Minneapolis in a commentary to accompany the report.
"It had been hypothesized that measures of central obesity such as waist and waist-hip ratio would be more strongly associated with cardiovascular risk than measures of global obesity (that is, BMI)," Huxley says. This thinking developed, she says, because in some studies, central obesity measures were more strongly linked with such conditions as type 2 diabetes, which in turn can boost heart disease.
The new research shows otherwise, suggesting that after adjusting for differences in age, gender, and smoking according to Huxley. ''There is very little difference between the three measures in terms of the strength of the relationship with cardiovascular disease."
The message, Huxley says, is to maintain a healthy body weight, meaning a BMI of 18.5 to 24.9.
Health experts say disease risk increases when a man's waist circumference is over 40 inches and a woman's waist circumference is over 35 inches.
To reduce cardiovascular disease risk, a man's waist-to-hip ratio (waist in inches divided by hips in inches) should 0.9 or less; a woman's waist-to-hip ratio should be 0.8 or less.
The Emerging Risk Factors Collaboration Coordinating Centre is supported by grants from the British Heart Foundation, the U.K. Medical Research Council, and other sources.
SOURCES: Emanuele Di Angelantonio, MD, PhD, lecturer, University of Cambridge, U.K.Rachel Huxley, DPhil, associate professor, University of Minnesota School of Public Health, Minneapolis.Huxley, R. The Lancet, published online March 11, 2011.Emerging Risk Factors Collaboration. The Lancet, published online March 11, 2011.