Body mass index in 17-year-old Israeli males of different ethnic backgrounds; national or ethnic-specific references?

To evaluate whether a single national reference is appropriate for assessin g prevalence of overweight in heterogeneous populations, or whether ethnic- specific references are needed. DESIGN: A population-based study of Israeli Jewish males who underwent rout ine physical and clinical examinations prior to army recruitment sewed ms t he basis for the development of two types of references for body mass index (BMI):: a national reference (NR) and an ethnic-specific reference (ER). SUBJEGTS: Consecutive cohorts of all 17-y-old Jewish male recruits (n = 109 , 570). MEASUREMENTS: Weight, height and blood pressure values were obtained. BMI w as calculated, and the 85th percentile of BMI was used as a cut-off point f or overweight, using both types of references. Prevalence of hypertension a mong recruits was used as a biomarker to support the reliability of the ER when discrepancy in classification between the two references was found, RESULTS: As compared to the NW, three ethnic groups had a BMI distribution shifted to the left (light sub-population) and five were shifted tee the ri ght (heavy sub-population). In the light sub-population, 7% of the inductee s who were classified as having normal weight by the NR were considered ove rweight by the ER and had a hypertension rate similar to that of those defi ned as overweight by both references (3.1 per 1000). In the heavy sub-popul ation the 4% of subjects who were overweight by NR and normal by ER had hyp ertension rates similar to those defined as normal weight by both reference s (2.7/1000), and significantly lower than that of those classified as over weight by both references (10.8/1000). CONCLUSION: In heterogeneous populations, ethnic references should be used to evaluate prevalence of overweight, rather than one national reference.