[Body mass index and cardiovascular events: the "obesity paradox"].

Excessive body mass among healthy subjects carries an increased risk of subsequent cardiovascular events. Excess weight implies the presence of white, viscero-abdominal fat, that promotes insulin-resistance, is infiltrated by macrophages, and is less differentiated compared to subcutaneous or brown fat. Conversely, among patients with cardiovascular disease, slim patients have a greater risk of recurrent atherothrombotic events than fatter patients ("obesity paradox"). Lean patients with cardiovascular disease, on average, have more comorbidities and haemorrhagic complications than their heavier counteparts, and probably they conceal predisposing factors that are still unknown and therefore difficult to treat.