Update: systemic diseases and the cardiovascular system (i): obesity and the heart.

Excess weight is the most prevalent cardiovascular risk factor and certainly the factor that improves the least over time among those with established cardiovascular disease. The association between obesity and cardiovascular disease is complex and not limited to the standard risk factors like hypertension, dyslipidemia, and type 2 diabetes mellitus. In recent years, multiple studies have shown that obesity may cause cardiovascular diseases via multiple disease mechanisms like subclinical inflammation, endothelial dysfunction, increased sympathetic tone, atherogenic lipid profiles, enhanced thrombogenic factors and also through obstructive sleep apnea. Despite the overwhelming data linking obesity to cardiovascular disease, several studies have shown a paradoxical association between obesity and prognosis among those with coronary disease and heart failure, which may be due to limitations of the way we currently define obesity. There is abundant data suggesting that measuring central obesity or total body fat content might be more appropriate than using the body mass index alone. The management of obesity is challenging and studies using lifestyle modification alone or with pharmacologic agents generally have limited success and high levels of weight regain. Bariatric surgery has proven to be an effective and safe way to induce and maintain significant weight loss but is limited to those with medically complicated obesity or people who are severely obese.