The Body Mass Index (BMI) has long been a controversial diagnostic tool, sparking debates among researchers, clinicians, and advocates. While it is widely used in health apps and clinical intake forms, there are growing concerns about its reliability and potential for disastrous outcomes, especially for racialized populations. But here's where it gets controversial...
Muna-Udbi Ali, an Assistant Professor at York University, shares her personal experience with the dangers of BMI. She recalls excruciating headaches that impacted her sight, leading her neurologist and ophthalmologist to insist she visit the emergency department. At the hospital, her weight was recorded, and her BMI calculated, indicating obesity. Instead of addressing her pain, she was advised to lose weight, with no additional tests conducted. It wasn't until her neurologist intervened that an MRI was ordered, revealing a blood clot in the brain, a condition unique to her in southern California due to COVID-19.
And this is the part most people miss...
BMI has a troubling history intertwined with racism. The Quetelet Index, its precursor, was used by Francis Galton, Charles Darwin's half-cousin, to compare racial characteristics in the 1880s. Nutritionist Ancel Keys later transformed it into the BMI we know today. The index was initially used to understand population-level differences, but it wasn't until the 1990s that it became a tool for individual assessment, coinciding with the rise of weight-loss medications.
But why is this controversial?
Ramanpreet Annie Bahra, co-founder of the Canadian Sociological Association's Fat Studies Research Cluster, questions the use of a tool designed to exclude people. Aly Bailey, an assistant professor, co-authored an article advocating for the refusal of BMI, highlighting its historical bias. The article, published in the Body Image journal, emphasizes the need to move away from BMI and towards more ethical ways of understanding bodies and sizes.
The challenges with BMI are not limited to its history. Roberta Heale, a nurse practitioner, points out that BMI issues are prevalent in menopause care. As estrogen levels drop, fat shifts from hips to the waist, becoming visceral fat, which poses a greater risk for chronic diseases. Yet, many menopausal patients experience no change in weight, yet their risk for cardiac issues and diabetes alters.
Gillian Booth, an endocrinologist, underscores the unreliability of BMI among racialized groups. She explains that different ethnic groups carry weight differently, with South and Southeast Asian populations at risk of diabetes at lower BMIs. Diabetes Canada acknowledges BMI's limitations, especially for athletes, people with larger bodies and little visceral fat, and individuals with disabilities.
And this is where it gets thought-provoking...
BMI is used in national and global reports on chronic disease risks, including by the Public Health Agency of Canada (PHAC). Justin Lang, a research scientist at PHAC, agrees on the limitations of BMI, especially at the individual level. However, he emphasizes that BMI is just one measure in a larger toolkit, and self-reported data from Statistics Canada is used for population-level analysis.
At the individual level, alternative approaches to BMI have been proposed. Michelle Acorn, CEO of the Nurse Practitioners' Association of Ontario, suggests that determining health should be left to qualified professionals, not a number. Body Roundness Index and waist circumference are potential alternatives, offering more information than BMI. Bone densitometry, while more precise, is resource-intensive and cannot be self-reported.
But what does this mean for the future?
The discussions around BMI have sparked a critical examination of how society values different bodies. Ali's experience and her work with Black communities highlight the intersection of race and health. Bailey advocates for moving away from BMI, emphasizing the need for ethical ways of understanding bodies and sizes, and giving individuals agency in self-description. For Bahra, this agency empowers patients to make choices, such as declining to be weighed during medical appointments.
