Obesity-associated morbidity
Obesity is a risk factor for many chronic physical and mental illnesses.
Health risks for those who are overweight may be decreasing because of improvements in medical care. Some obesity-associated medical conditions may be the result of stress caused by medical discrimination against people who are obese, rather than the direct effects of obesity, and some may be exacerbated by the relatively poor healthcare received by people who are obese.
Medical discrimination
Because of the social stigma of obesity, people who are obese may receive poorer healthcare than people within the normal BMI weight range, potentially contributing to the relationship between obesity and poor health outcomes. People who experience weight-related discrimination, irrespective of their actual weight status, similarly have poorer health outcomes than those who do not experience weight-related discrimination. People who are obese are also less likely to seek medical care than people who are not obese, even if the weight gain is caused by medical problems. Peter Muennig, a professor in the Department of Health Policy and Management at Columbia University, has proposed that obesity-associated medical conditions may be caused "not from adiposity alone, but also from the psychological stress induced by the social stigma associated with being obese".Cardiological risks
Body weight is not considered to be an independently predictive risk factor for cardiovascular disease by current risk assessment tools. Mortality from cardiovascular disease has decreased despite increases in obesity, and at least one clinical trial was stopped early because the weight loss intervention being tested did not reduce cardiovascular disease.Ischemic heart disease
Abdominal obesity is associated with cardiovascular diseases including angina and myocardial infarction. However, overall obesity may lead to false diagnoses of myocardial infarction and may decrease mortality after acute myocardial infarction.In 2008, European guidelines concluded that 35% of ischemic heart disease among adults in Europe is due to obesity.
Congestive heart failure
Having obesity is associated to about 11% of heart failure cases in males and 14% in females.High blood pressure
More than 85% of those with hypertension have a BMI greater than 25, although diet is probably a more important factor than body weight. Risk estimates indicate that at least two-thirds of people with hypertension can be directly attributed to obesity. The association between obesity and hypertension has been found in animal and clinical studies, which have suggested that there are multiple potential mechanisms for obesity-induced hypertension. These mechanisms include the activation of the sympathetic nervous system as well as the activation of the renin–angiotensin–aldosterone system. As of 2007, it was unclear whether there is an association between hypertension and obesity in children, but there is little direct evidence that blood pressure has increased despite increases in pediatric overweight.Abnormal cholesterol levels
Obesity is associated with increased levels of LDL cholesterol and lower levels of HDL cholesterol in the blood.Deep vein thrombosis and pulmonary embolism
Obesity increases one's risk of venous thromboembolism by approximately 2.3 fold.Dermatological risks
Obesity is associated with the incidence of stretch marks, acanthosis nigricans, lymphedema, cellulitis, hirsutism, and intertrigo.Endocrine risks
Diabetes mellitus
The link between obesity and type 2 diabetes is so strong that researchers in the 1970s started calling it "diabesity". Excess weight is behind 64% of cases of diabetes in males and 77% of cases in females.Gynecomastia
In some individuals, obesity can be associated with elevated peripheral conversion of androgens into estrogens.Gastrointestinal risks
Gastroesophageal reflux disease
Several studies have shown that the frequency and severity of GERD symptoms increase with BMI, such that people who are underweight have the fewest GERD symptoms, and people who are severely obese have the most GERD symptoms. However, most studies find that GERD symptoms are not improved by nonsurgical weight loss.Cholelithiasis (gallstones)
Obesity causes the amount of cholesterol in bile to rise, in turn the formation of stone can occurReproductive system (or genital system)
Polycystic ovarian syndrome (PCOS)
Due to its association with insulin resistance, the risk of obesity increases with polycystic ovarian syndrome. In the US approximately 60% of patients with PCOS have a BMI greater than 30. It remains uncertain whether PCOS contributes to obesity, or the reverse.Infertility
Obesity can lead to infertility in both males and females. This is primarily due to excess estrogen interfering with normal ovulation in females and altering spermatogenesis in males. It is believed to cause 6% of primary infertility. A review in 2013 came to the result that obesity increases the risk of oligospermia and azoospermia in males, with an of odds ratio 1.3. Being morbidly obese increases the odds ratio to 2.0.Complications of pregnancy
Obesity is related to many complications in pregnancy including: haemorrhage, infection, increased hospital stays for the mother, and increased NICU requirements for the infant. Obese females also have increased risk of preterm births and low birth weight infants.Obese females have more than twice the rate of C-sections compared to females of "normal" weight. Some have suggested that this may be due in part to the social stigma of obesity.
Birth defects
Those who are obese during pregnancy have a greater risk of having a child with a number of congenital malformations including: neural tube defects such as anencephaly and spina bifida, cardiovascular anomalies, including septal anomalies, cleft lip and palate, anorectal malformation, limb reduction anomalies, and hydrocephaly.Intrauterine fetal death
Maternal obesity is associated with an increased risk of intrauterine fetal death.Buried penis
Excess body fat in morbid obesity can, in some cases, completely obscure or "bury" the penis.Neurological risks
Stroke
Ischemic stroke is increased in both men and women who are obese, however the increase in risk is due to other metabolic health issues such as hypertension, increased blood pressure, decreased high-density lipoprotein, triglycerides or glucose, or diabetes.Meralgia paresthetica
Meralgia paresthetica is a neuropathic pain or numbness of the thighs, sometimes associated with obesity.Migraines
Migraine is comorbid with obesity. The risk of migraine rises 50% by BMI of 30 kg/m2 and 100% by BMI of 35 kg/m2. The causal connection remains unclear.Carpal tunnel syndrome
The risk of carpal tunnel syndrome is estimated to rise 7.4% for each 1 kg/m2 increase of body mass index.Dementia
One review found that those who are obese do not have a significantly higher rate of dementia than those with "normal" weight.Idiopathic intracranial hypertension
Idiopathic intracranial hypertension, or unexplained high pressure in the cranium, is a rare condition that can cause visual impairment, frequent severe headache, and tinnitus. It is most commonly seen in obese women, and the incidence of idiopathic intracranial hypertension is increasing along with increases in the number of people who are obese.Multiple sclerosis
Obese female individuals at 18 years of age have a greater than twofold increased risk of multiple sclerosis compared to females with a BMI between 18.5 and 20.9. Female individuals who are underweight at age 18 have the lowest risk of multiple sclerosis. However, body weight as an adult was not associated with risk of multiple sclerosis.Cancer
Many cancers occur at increased frequency in those who are overweight or obese. A study from the United Kingdom found that approximately 5% of cancer is due to excess weight. These cancers include:- breast cancer
- ovarian cancer
- esophageal cancer
- colorectal cancer
- hepatocellular carcinoma
- pancreatic cancer
- gallbladder cancer
- stomach cancer
- endometrial cancer
- cervical cancer
- prostate cancer
- renal cell carcinoma
- non-Hodgkin's lymphoma
- multiple myeloma
Psychiatric risks
Depression
Obesity has been associated with depression, likely due to social factors rather than physical effects of obesity. However, it is possible that obesity is caused by depression. Obesity-related disabilities may also lead to depression in some people. Repeated failed attempts at weight loss might also lead to depression.The association between obesity and depression is strongest in those who are more severely obese, those who are younger, and in women. Suicide rate however decreases with increased BMI. Similarly, weight loss through bariatric surgery is associated with increased risk of suicide.