[The obesity paradox]. / Le paradoxe de l'obésité.

In general population, cardiovascular (CV) mortality increases in parallel with obesity severity, determined by body mass index (BMI). However in cohorts of patients with coronary diseases or heart failure a decrease of the global mortality has been observed in patients aged more than 65 years old with moderate obesity (BMI = 30-35) compared to normal weight people (BMI = 20-25) and morbid obese (BMI > 35). This "obesity paradox" could result from the selection of obese people with healthy metabolic profile and way of life. BMI does not allow to distinguish lean body mass from fat mass and therefore to evaluate abdominal obesity which is associated with metabolic syndrome and CV risk.