A new study shows Body Mass Index (BMI) is not the best way to determine cardiovascular risk in Bronx residents. The flaw in the BMI, the standard test for obesity, according to health officials is the test?s inability to distinguish the difference between fat and muscle. BMI is calculated by taking a patient?s weight in kilograms and dividing that number by the patient?s height in meters and then squaring the figure. BMI?s between 18 and 24 are considered healthy. BMI?s over 25 are considered overweight and a BMI of 30 or more is considered obese. Authors of the study say a more accurate system needs to be developed. They recommend using a test that focuses on a patient?s waist-to-hip ratio. Health officials tracked 250,000 people over a 4-year period, repeatedly checking their BMI numbers. Critics of the study say four years is not long enough to determine whether the patient?s BMI?s are affecting their cardiovascular health. Related Information: Centers for Disease Control and Prevention