Obesity is a risk factor for premature death, diabetes mellitus, and cardiovascular diseases. However, this rule does not always work. In a minority of cases, obesity does not lead to serious consequences. This phenomenon is called metabolically healthy obesity (MHO).
Scientists still have not agreed on clear criteria under which obesity can be called metabolically healthy. Previously, it was proposed to consider it as such if metabolic syndrome or tissue resistance to insulin did not develop against its background. However, large studies have shown that in obese people without metabolic syndrome, the risk of death from all causes and from heart disease may remain elevated (higher than in people of normal weight). That is, it is not always possible to call such obesity healthy. Other wording, for example, taking into account the waist circumference, also did not receive universal acceptance.
A new formulation of metabolically healthy obesity
A group of German scientists has developed an alternative approach to the definition of MLO. They analyzed data from more than 380 thousand people, taken from two databases: the British Biobank and a large study NHANES (it was devoted to the relationship between nutrition and health). The average age of the participants was 41-56 years old.
The authors concluded that metabolically healthy obesity meets the following criteria:
- systolic (upper) blood pressure – not higher than 130 millimeters of mercury without the use of drugs for hypertension;
- the ratio of waist to hip coverage – no more than 0.95 for women and 1.3 for men;
- absence of type 2 diabetes mellitus.
Participants a study with an MHO that met these criteria, during 8-14 years of follow-up, the risk of death from cardiovascular diseases and from all causes was practically the same level as in people without obesity.
The authors found that levels of “bad cholesterol” and other blood lipids, contrary to expectations, did not significantly affect the risk of death of obese study participants. Therefore, this indicator was not included in the definition of the MLO.
The scientists pointed out that their definition of MLO can only apply to people whose BMI is no more than 40. People with severe obesity increase the risk of death, regardless of other criteria.
Why the new MLT criterion may be more accurate
In an editorial published in the JAMA Network Open, scientists from the Albert Einstein College of Medicine followed up on the study’s authors. They pointed out that body mass index is not always a reliable criterion for determining health risks. In addition to it, it is often assessed whether a person has central (abdominal) obesity. Most often, the waist measurement is used for this. However, a more sensitive diagnostic method is to assess the ratio of the waist to the hip. It, the authors of the article point out, most accurately predicts the risk of cardiovascular disease.