Body Fat and Body-Mass Index among a Multiethnic Sample of College-Age Men and Women

Abstract

Obesity prevalence and average body composition vary by US race and gender. Asian Americans have the lowest prevalence of obesity. Relying on body-mass index (BMI) to estimate obesity prevalence may misclassify subgroups that appear normally weighted but have excess body fat. We evaluated percentage body fat (PBF) and BMI to determine whether BMI reflects PBF consistently across different races. 940 college students were recruited from a local public university over four consecutive years. We measured PBF by bioelectrical impedance analysis (BIA), weight by physicians' scales, and height with stadiometers. Our sample comprised Asians (49%), Caucasians (23%), Hispanics (7%), and Other (21%). Participants averaged 21.4 years old; BMI was 22.9 kg/m2; PBF was 24.8%. BMI and PBF varied significantly by race and gender (P value = 0.002 and 0.005 for men; 0.0009 and 0.0008 for women). Asian-American women had the lowest BMI (21.5 kg/m2) but the second highest PBF (27.8%). Linear association between BMI and PBF was the weakest (r 2 = 0.09) among Asian-American women and BMI had the poorest sensitivity (37%) to detect PBF. The high PBF with low BMI pattern exhibited by Asian-American women suggests that they could escape detection for obesity-related disease if BMI is the sole measure that estimates body composition.

Genetic variation near IRS1 is associated with adiposity and a favorable metabolic profile in U.S.Hispanics/Latinos

“…However, it is unclear whether the observed ethnic‐difference in genetic effect is related to different fat deposition between Hispanic/Latino women and European women. Hispanic/Latino women have higher prevalence of obesity and higher BF% than non‐Hispanic white women , but comparison of accurate fat deposition between them need further investigations. In addition, it is should be noted that the previous GWAS in Europeans included multiple cohorts using bioimpedance analysis (BIA) and/or dual‐energy X‐ray absorptiometry (DEXA) measures , while we used Tanita‐BIA to estimate BF%.…”

Indexing adult obesity by waist-to-height and weight-to-height ratios

“…It had been shown, for example, that fatness of Asian-American women, but not men, is underestimated by their BMI 2 . [29] Associated with the weight gain with age is also the gluteal-femoral deposition of fat in women before menopause, [20] which unlike all previous would render a larger BMI 2 whilst a smaller WCHR.…”

Obesity and Headache: Part I – A Systematic Review of the Epidemiology of Obesity and Headache

“…In addition to sex‐specific differences, racial differences in adipose tissue distribution, as well as in obesity, have been identified . In the United States, obesity prevalence (based on BMI) has been reported to be greatest in African Americans, followed by Caucasians, and lowest in Asian Americans . However, notably given the same BMI, Asians have a higher TBF percentage compared with their Caucasian counterparts; and black women have a lower TBF percentage compared with white women …”