Body Mass Index (BMI): Is a Sufficient Indicator of Metabolic Health?

A person’s body mass index (BMI) is often used as an indicator of their general health, but that’s not always the most accurate tool, according to research being presented Friday at ENDO 2023, the Endocrine Society’s annual meeting in Chicago, Ill. They also found that a high proportion of U.S. adults with normal BMI still have obesity. Researchers show that there are racial/ethnic differences in body fat, BMI, and body fat distribution which may provide evidence for future Studies to further determine if these differences are possible drivers of the racial disparities seen in cardio-metabolic diseases (1^✔ ✔Trusted Source
Body Mass Index: Obesity, BMI, and Health: A Critical Review

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Body Mass Index May Not Be the Best Indicator of Health

They identified non-pregnant U.S. adults aged 20-59 years from the 2011-2018 National Health and Nutrition Examination Survey (NHANES) with whole-body DEXA scan data. Their BMI was categorized by ethnicity (non-Asian: underweight<18.5, normal=18.5-24.9, overweight=25-29.9, obese≥30 kg/m2, Asian: <18.5, 18.5-22.9, 23-27.4, 27.5+).

The researchers estimated the odds of obesity among adults as normal/overweight based on BMI or total body fat percentage (BF%) as ≥25% in males and ≥32% in females, by race (non-Hispanic White [NHW], non-Hispanic Black [NHB], Asian, Hispanic, and other). They also estimated mean DEXA adiposity measures by race.

They found that nearly 36% had a BMI≥30 (the traditional definition of obesity) but 74% had obesity per BF%. Among normal BMI adults, 44% of non-Hispanic Whites, 27% of NHB, 49% of Hispanic, and 49% of Asians had obesity as per BF%. Among normal BMI adults, the mean android-to-gynoid fat ratio was 0.84 for NHW, 0.85 for NHB, 0.89 for Hispanics, and 0.91 for Asians.

Nearly 3 in 4 young-to-middle-aged U.S. adults were considered to have obesity according to BF% from DEXA scans. Asian Americans and Hispanics with seemingly normal BMI were more likely to have obesity, and more likely to have a greater proportion of abdominal fat than non-Hispanic Whites (2^✔ ✔Trusted Source
Racial Disparities and Cardiometabolic Risk: New Horizons of Intervention and Prevention

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Non-Hispanic Blacks had significantly lower chances of obesity at normal/overweight BMI ranges and a lower proportion of abdominal fat. This research will add to the idea of weight-inclusive care and allow clinicians to routinely use supplementary measures of body fat such as waist circumference or bioimpedance-based body fat measurements in addition to BMI.

Engaging in practices to prevent unconscious biases that may occur when caring for a patient with obese BMI, and engaging in clinical decision-making that is not solely dependent on a BMI calculation but rather an overall idea of body composition and body fat distribution.

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References:

1. Body Mass Index: Obesity, BMI, and Health: A Critical Review - (https://journals.lww.com/nutritiontodayonline/Fulltext/2015/05000/Body_Mass_Index__Obesity,_BMI,_and_Health__A.5.aspx)
2. Racial Disparities and Cardiometabolic Risk: New Horizons of Intervention and Prevention - (https://link.springer.com/article/10.1007/s11892-022-01451-6)

Source-Eurekalert