Effects on health : Obesity

Excessive body weight is associated with various diseases, particularly cardiovascular diseases, diabetes mellitus type 2, obstructive sleep apnea, certain types of cancer,osteoarthritis^[2] and asthma.^[2][22] As a result, obesity has been found to reduce life expectancy.^[2]

Mortality

Relative risk of death over 10 years for white men (left) and women (right) who have never smoked in the United States by BMI.^[23]

Obesity is one of the leading preventable causes of death worldwide.^[24][25][26] Large-scale American and European studies have found that mortality risk is lowest at a BMI of 20–25 kg/m^2[23][27] in non-smokers and at 24–27 kg/m² in current smokers, with risk increasing along with changes in either direction.^[28][29] In Asians risk begins to increase between 22–25 kg/m².^[30] A BMI above 32 kg/m² has been associated with a doubledmortality rate among women over a 16-year period.^[31] In the United States obesity is estimated to cause 111,909 to 365,000 deaths per year,^[2][26] while 1 million (7.7%) of deaths in Europe are attributed to excess weight.^[32][33] On average, obesity reduces life expectancy by six to seven years,^[2][34] a BMI of 30–35 kg/m²reduces life expectancy by two to four years,^[27] while severe obesity (BMI > 40 kg/m²) reduces life expectancy by ten years.^[27]

Morbidity

Obesity increases the risk of many physical and mental conditions. These comorbidities are most commonly shown in metabolic syndrome,^[2] a combination of medical disorders which includes: diabetes mellitus type 2, high blood pressure, high blood cholesterol, and high triglyceride levels.^[35]

Complications are either directly caused by obesity or indirectly related through mechanisms sharing a common cause such as a poor diet or a sedentary lifestyle. The strength of the link between obesity and specific conditions varies. One of the strongest is the link with type 2 diabetes. Excess body fat underlies 64% of cases of diabetes in men and 77% of cases in women.^[36]

Health consequences fall into two broad categories: those attributable to the effects of increased fat mass (such as osteoarthritis, obstructive sleep apnea, social stigmatization) and those due to the increased number of fat cells (diabetes, cancer, cardiovascular disease, non-alcoholic fatty liver disease).^[2][37] Increases in body fat alter the body's response to insulin, potentially leading to insulin resistance. Increased fat also creates a proinflammatory state,^[38][39] and a prothrombotic state.^[37][40]

Medical field	Condition	Medical field	Condition
Cardiology	coronary heart disease:[41] angina and myocardial infarction congestive heart failure[2] high blood pressure[2] abnormal cholesterol levels[2] deep vein thrombosis and pulmonary embolism[42]	Dermatology	stretch marks[43] acanthosis nigricans[43] lymphedema[43] cellulitis[43] hirsutism[43] intertrigo[44]
EndocrinologyandReproductive medicine	diabetes mellitus[2] polycystic ovarian syndrome[2] menstrual disorders[2] infertility[2][45] complications during pregnancy[2][45] birth defects[2] intrauterine fetal death[45]	Gastrointestinal	gastroesophageal reflux disease[8] fatty liver disease[8] cholelithiasis (gallstones)[8]
Neurology	stroke[2] meralgia paresthetica[46] migraines[47] carpal tunnel syndrome[48] dementia[49] idiopathic intracranial hypertension[50] multiple sclerosis[51]	Oncology[52]	esophageal colorectal pancreatic gallbladder, endometrial kidney Leukemia Hepatocellular carcinoma[8] malignant melanoma
Psychiatry	depression in women[2] social stigmatization[2]	Respirology	obstructive sleep apnea[2][22] obesity hypoventilation syndrome[2][22] asthma[2][22] increased complications during general anaesthesia[2][5]
RheumatologyandOrthopedics	gout[53] poor mobility[54] osteoarthritis[2] low back pain[55]	Urology and Nephrology	erectile dysfunction[56] urinary incontinence[57] chronic renal failure[58] hypogonadism[59] buried penis[60]