Nirav Shah of NYU School of Medicine and Eric Braverman of Weill-Cornell Medical College have published more evidence on the limitations of the Body Mass Index (BMI). Their study looked at adults according to BMI, DXA, fasting leptin and insulin. 39% of the subjects were found to be obese by DXA (which is a direct measurement of body fat) but not by BMI. BMI misclassified 25% of the men and 48% of the women. A strong relationship was found between increased leptin levels and increased body fat. Women demonstrated a clear correlation between advancing age and increasing miscalculation, with over half misclassified by age 60-69. This association was not apparent for men.
The authors state, “BMI significantly underestimates adiposity. A better cutpoint for obesity with BMI is 24 for females and 28 for males. ..Obesity, body fat and increased adiposity are more prevalent than the American public and American physicians are aware of. This is contributing greatly to multiple co-morbidities such as hyperlipidemia, coronary artery disease, hypertension, and diabetes. The current systematic underestimation of adiposity in large scale studies, and subsequent use of such studies for public health policy-making, can readily be corrected, resulting in a more appropriate sense of urgency and more cogent weighing of public health priorities.” PubMed: Measuring Adiposity in Patients