Medical consequences of obesity

Obesity is now one of the most important global public health issues and preventable causes of disease and mortality. In 2004, increased BMI alone was estimated to account for 2.8 million deaths; when combined with physical inactivity the total was 6.0 million, surpassing the excess mortality associated with tobacco, and approaching that of high blood pressure, the top risk factor for death. Type 2 diabetes mellitus is strongly linked with obesity – a 25% increase in risk for every 1 kg/m2 increase in BMI above 22. Obesity has a particular impact on the cardiovascular system including an increased prevalence of heart failure, hypertension and coronary heart disease. Obstructive sleep apnoea, symptoms of breathlessness and asthma are all more common in the obese. Non-alcoholic fatty liver disease, and its transition to non-alcoholic steatohepatitis, threatens to become the leading cause of cirrhosis and hepatocellular carcinoma. Many cancers are more common in the obese and the outcome of treatment is often less successful. Psychosocial and psychiatric consequences of obesity are also increasingly recognized. It is estimated that in Europe 2–8% of health care budgets are spent on obesity-related disease, equating to 0.6% of gross domestic product.