BOSTON — Dual x-ray absorptiometry was a more accurate predictor of obesity than was body mass index in a retrospective comparison of the two measures in 1,234 adults.
Despite its widespread use, BMI is not an accurate indicator of body fat. Direct measures of adiposity, such as those obtained by dual x-ray absorptiometry (DXA), are far more precise, Dr. Eric R. Braverman and his associates reported in a poster at the meeting.
Records of 1,234 private adult outpatients (490 men, 744 women) who had both BMI and DXA measurements during 2003–2009 were analyzed. They had a mean age of 51 years, a mean BMI of 26.2 kg/m
Thus, 37% of patients were misclassified by BMI: 452 were found to be obese by DXA but nonobese by BMI and 12 were obese by BMI but not by DXA. The 66% of patients classified as obese by DXA but who were “missed” by BMI had lower muscle and lean body mass, said Dr. Braverman of the department of neurological surgery at Weill Cornell Medical College, New York.
“We have shown that BMI is a highly insensitive measure, resulting in an underdiagnosis of obesity. If we can extrapolate from the rest of our data on the national scale, it is very likely that obesity is a much bigger epidemic than is currently acknowledged,” they said.
This study was funded by the private nonprofit PATH Foundation in New York. Dr. Braverman stated that he had no other financial disclosures.
The 66% of patients classified as obese by DXA but who were 'missed' by BMI had lower muscle mass.
Source DR. BRAVERMAN