Obesity contributes to the development of several health disorders including type 2 diabetes, arthritic deformity of the joints, high blood pressure, heart disease, stroke, and several types of cancers. Increased body fat can be distributed in different parts of the body. The influence on your health is determined by the place where fat accumulated. Central obesity, which occurs by accumulating visceral brown fat in the abdomen, has a more detrimental effect on overall health compared to other types of fat.
We have previously discussed the finding that patients with coronary artery disease who had central obesity had greater than 2 times the risk of death when compared to those patients who carried extra weight in other parts of their body.
Intra-abdominal or visceral brown fat is more metabolically active, can contribute to insulin resistance and diabetes, can release cholesterol and fatty acid molecules into the blood which can damage the lining of the vasculature which can lead to heart attack and stroke. Body fat distribution is an important factor in determining the risk for cardiovascular disease and other disorders such as the metabolic syndrome.
Researchers, led by Dr. Francisco Lopez-Jimenez from the Mayo Clinic in Rochester, Minnesota, have found that individuals with increased belly fat but normal overall weight have increase risk of cardiovascular disease. The results of their research were reported at the annual meeting of the European Society of Cardiology in Munich, Germany.
The researchers studied the influence of central obesity in normal weight individuals by measuring body mass index (BMI) and waist to hip ratio (WHR). Central obesity was defined as an elevated waist to hip ratio, which represented increased intra-abdominal fat.
The study included 12,785 participants in the National Health and Nutrition Examination Surveys III (NHANES III), which is considered a good representation of the adult US population. The mean age of the study participants was 44 years and 47.4% were men. The study participants were followed for 14.3 years during the course of the study.
The researchers found that individuals with normal weight and central obesity were 2.75 times more likely to die of cardiovascular disease and 2.08 times more likely to die of all cause mortality when compared to individuals with normal weight and normal waist to hip ratio.
The authors wrote, “Normal weight central obesity yields the highest mortality risk of all the combinations using BMI and fat distribution categories. This pattern of obesity is associated with levels of risk higher than nearly any previously reported anthropometric measure”.
Dr. Karine Sahakyan is quoted as saying, “The high risk of death may be related to a higher visceral fat accumulation in this group, which is associated with insulin resistance and other risk factors, the limited amount of fat located on the hips and legs, which is fat with presumed protective effects and to the relatively limited amount of muscle mass”.
In addition Dr. Francisco Lopez-Jimenez is quoted as saying, “Our research shows that if a person has a normal BMI, this by itself should not reassure them that their risk for heart disease is low. Where their fat is distributed on their body can mean a lot, and that can be determined easily by getting a waist-to-hip measurement, even if their body weight is within normal limits”.
This study gives more evidence that intra-abdominal fat has negative effects on health, even in those individuals with normal weight as measured by BMI. In addition to measuring BMI, an additional measure of central obesity using the waist to hip ratio should also be used to determine levels of obesity and the risk that obesity has on overall health. With the growing obesity epidemic in the world, determining the type of fat that is present on the body will be even more important as shown by this study. Clearly, central obesity is the more detrimental of the types of fat and we should all strive to decrease intra-abdominal fat with dieting and regular exercise.
Karine Sahakyan et al. “Normal-weight central obesity and cardiovascular mortality risk in the US population” Aug. 27, 2012, Abstract 2951, European Society of Cardiology Congress, Munich, Germany
European Society of Cardiology Press Release: Normal weight individuals with belly fat at highest CVD risk