Obesity (esp. abdominal type) was still considered as a risk factor for cardiovascular disease. During the last decade has a new phenomenon appeared: "obesity paradox", i.e. patients with high BMI die less frequently than patients with low BMI.
Obesity paradox was described first in patients with chronic renal failure, heart failure or in oncological patients, later on in patients with cardiovascular disease and now also in patients with type 2 diabetes. In comparison with population studies, BMI associated with low cardiovascular mortality in patients with Type 2 diabetes is shifted to the higher level than in subjects from general population.
Mechanisms of obesity paradox is not yet clarified.