Evaluation Of A New Waist Circumference Equation To Predict Percent Fat For Military Personnel

The United States military continues to search for a fair and equitable procedure to assess body composition among its active-duty personnel. The need remains for a simple yet accurate assessment tool to alleviate the need for expensive laboratory equipment and extensive time commitment. Recently a new waist circumference technique was proposed to estimate %fat in military men and women. Thus far this approach has not been cross validated to assess its applicability in young men. PURPOSE: To evaluate the accuracy of a new waist circumference equation to estimate %fat in college football athletes. METHODS: Members of a college football team (n = 120, age = 20.7 ± 1.3 yrs, height = 181.7 ± 6.0 cm, weight = 100.0 ± 17.6 kg) were measured for %fat using dual-energy X-ray absorptiometry (DXA). Waist circumference (WC) was measured at the level of the umbilicus and applied with body weight in the new equation to estimate %fat. RESULTS: Cross-validation of the new equation significantly underpredicted %fat (18.8 ± 5.6%) compared to DXA (21.6 ± 7.7%) despite a high correlation between the values (r = 0.84, p < 0.001). Using current military %fat cut-off criteria, 36% of these men would have been denied military service using DXA while 26% would have been denied military service by the prediction equation. DXA and the WC equation agreed on 20% of the participants. CONCLUSION: These results suggest a newly developed predicted equation derived from DXA for military screening tends to underpredict %fat in a sample of physical fit college football players. Further cross-validating on a separate sample of military personnel using DXA needs to be done prior to adopting the new equation. In addition, a reassessment of the %fat scale for acceptable military service may need to be done since DXA typically presents higher %fat values than all other techniques.