A comparison of the Slaughter skinfold-thickness equations and BMI in predicting body fatness and cardiovascular disease risk factor levels in children.

BACKGROUND Although estimation of percentage body fat with the Slaughter skinfold-thickness equations (PBF(Slaughter)) is widely used, the accuracy of this method has not been well studied. OBJECTIVE The objective was to determine the accuracy of the Slaughter skinfold-thickness equations. DESIGN We compared agreement between PBF(Slaughter) and estimations derived from dual-energy X-ray absorptiometry (PBF(DXA)) in 1169 children in the Pediatric Rosetta Body Composition Project and the relation to cardiovascular disease risk factors, as compared with body mass index (BMI), in 6725 children in the Bogalusa Heart Study. RESULTS PBF(Slaughter) was highly correlated (r = 0.90) with PBF(DXA), but it markedly overestimated levels of PBF(DXA) in children with large skinfold thicknesses. In the 65 boys with a sum of skinfold thicknesses (subscapular- plus triceps-skinfold thicknesses) ≥ 50 mm, PBF(Slaughter) overestimated PBF(DXA) by 12 percentage points. The comparable overestimation in girls with a high skinfold sum was 6 percentage points. We also found that, after adjustment for sex and age, BMI showed slightly stronger associations with lipid, lipoprotein, insulin, and blood pressure values than did PBF(Slaughter). CONCLUSIONS These results indicate that PBF(Slaughter), which was developed among a group of much thinner children and adolescents, is fairly accurate among nonobese children, but markedly overestimates the body fatness of children who have thick skinfold thicknesses. Furthermore, PBF(Slaughter) has no advantage over sex- and age-adjusted BMIs at identifying children who are at increased risk of cardiovascular disease based on lipid, lipoprotein, insulin, and blood pressure values.