New analysis of the Framingham Heart Study has indicated that the way fat is distributed within the body may be more indicative of heart disease risk than body mass index (BMI) or waist circumference.

BMI measurement is one of the main indicators of risk of heart disease currently used, and is included in the Framingham risk score assessment, which measures factors of health that tend to correlate with heart attacks.

Researchers from the National Heart, Lung and Blood Institute in Massachusetts are now questioning whether BMI is an accurate enough indicator, when compared to results from a CT scan, focusing on the way that fat is distributed throughout the body.

The results of the analysis, published in the American College of Cardiology, indicate that higher volume of abdominal fat, especially visceral fat, is associated with a worse cardiovascular risk, more so than any risk relation seen with just BMI or waist circumference.

The CT scan, or computed tomography test, uses computer processing to patch together a series of images to give detailed cross sections of the body, letting doctors see inside in much greater detail than a conventional x-ray.

The issue that the study’s lead author, Dr Jane J Lee, and colleagues are highlighting is that fat may be more harmful in some areas of the body than in others, and BMI does not take into account fat distribution.

Furthermore, waist circumference is not as accurate as we might think, as the same two waist circumferences can be made up of different fat compositions – such as differing ratios of subcutaneous abdominal fat to intra-abdominal fat, both of which have differing effects on the risk of heart disease.

Overall, the study found that increased visceral fat raised other cardiovascular risk factors, such as high cholesterol levels, hypertension, high triglycerides, and metabolic syndrome, higher than increases in subcutaneous fat did.