The size of a person's belly is a better indicator of heart disease than how obese he or she is, says a new study.
Body Mass Index (BMI) was earlier used as a measure to predict heart disease risk. But a person could have a high BMI because he or she is muscular as opposed to fat, according to the health portal Medical News Today.
Carlos Iribarren and colleagues of the research division of Kaiser Permanente of Northern California in Oakland studied another factor known as sagittal abdominal diameter (SAD), a measure of "visceral obesity".
SAD is also called "supine abdominal height" which has been used to predict mortality in men, and is a measure of the girth around the abdomen - half way between the top of the pelvis and lower ribs.
It is considered a more reliable measure of a person's girth than the waistline, and the measurement is taken by a health professional using a caliper.
The scientists performed a cohort study involving 101,765 male and female members of the Kaiser Permanente of Northern California. They had been through health checks between 1965 and 1970 where their SAD was recorded, and a follow-up check was done 12 years later.
After adjusting for a number of social and lifestyle factors such as age, sex, education, BMI, smoking, alcohol and Hormone Replacement Therapy (HRT) in women, they found that men in the top 25 percent of SAD girth measurement had a 42 percent higher risk of coronary heart disease (CHD) than those in the bottom 25 percent of SAD girth measurement.
For women the figure was 44 percent, said the study published in the American Journal of Epidemiology.
The researchers also looked at the results within categories of BMI. They found that within the same BMI range, the SAD measure was a reliable predictor of CHD risk.
"Two people with the same Body Mass Index (even if their weight was 'normal') would effectively have different risks of developing CHD depending on the size of their belly - the larger the belly the bigger the risk", the researchers said.
They also found that SAD was a consistent predictor for CHD across racial groups. However, the younger a person was, regardless of race, the stronger the link between SAD and eventually having CHD.