Can people self-diagnose cancer or other diseases based on waist circumference or BMI? No, that's not true. The home measurement of waist circumference is misleading data that says nothing without further medical context because people have different body compositions.
The misleading information about cancer self-test appeared in a video (archived here) published on TikTok by user @leozl on December 6, 2022, under the title "Diabetes, cancer, heart attack, high blood pressure, high cholesterol can all be caused by insulin resistance and sugar addiction. Take a test at home to see if you are also in the risk group." The video (translated from the Czech language by Lead Stories) opened:
If you are at risk of diabetes or cancer, it may be due to insulin resistance, which I talked about recently. But now to the test. You will only need one thing and that is a measuring tape. If you don't have it at home, take a string and then attach it to a normal meter. Whatever you have, measure your waistline with it. If you are a woman and your body circumference is 80 centimeters or more, you are in the risk group. For men, it is 94 centimeters and more. Then type "BMI calculator" into your internet browser and fill in the required values. If your BMI is 25 or more, there is a good chance that you suffer from insulin resistance. The higher the values, the higher the chance that you have insulin resistance and therefore also that you will have type 2 diabetes, cancer, heart attack, stroke, high blood pressure, or high cholesterol.
This is what the post looked like on TikTok at the time of writing:
(Source: TikTok screenshot taken on Thu June 8 08:26:30 2023 UTC)
Many studies proved that body weight and composition are connected with several common cancers or other problems. However, not only obese people but also athletes can have a high BMI or waist circumference. Body composition is highly variable between individuals with significant differences, for example according to age, so identifying diseases based on mentioned measurements may show correlation but not causes of diseases. Patients with the same BMI can have significantly different body compositions and outcomes.
International Agency for Research on Cancer (IARC) concluded that there is evidence that higher amounts of body fat are associated with an increased risk of several cancers but that people shouldn't rely on a self-test that doesn't consider the wider medical context.
