Obesity is when your body weight is above normal. Obesity is a disease which can result in a lot of damage to your body. People with severe obesity are more likely to have other diseases. These include type 2 diabetes, high blood pressure, high cholesterol, heart disease, sleep apnea, and many more. Combined with obesity, these diseases may lead people to have poor health. In some cases, these can lead to a poor quality of life, disability, or early death.

Diabetes

Obesity is a major cause of Type 2 diabetes. Diabetes occurs when blood sugar is too high for your body to manage. People affected by obesity are about 10 times more likely to have high blood sugar (1). Type 2 diabetes can nearly double the risk of death (2). Type 2 diabetes can lead to:

• Amputations (loss of limbs)
• Heart disease 
• Stroke 
• Blindness 
• Kidney disease 
• High blood pressure
• Nerve damage and numbness
• Hard-to-heal infections
• Impotence
• And more

Hypertension

Obesity is a major cause for high blood pressure (also known as “hypertension”) (3). About three out of four patients with high blood pressure have obesity (4). High blood pressure increases the risk of other diseases such as heart disease, congestive heart failure (CHF), stroke, and kidney disease.

Heart Disease

Heart disease kills about 600,000 people every year in the United States. The American Heart Association considers obesity a major cause of heart disease. Large studies show that the risk for heart disease increases with obesity (5). People with severe obesity are at a higher risk having a heart attack.

Obesity increases your risk of heart failure. Severe obesity is associated with irregular heartbeats (arrhythmias, or a heart beat that is not normal). These arrhythmias can triple the risk of cardiac arrest (cardiac arrest is when the heart stops beating).

Respiratory Disorders

People with obesity have reduced breath capacity. They are not able to breathe in as much air in and out. These people are at higher risk for respiratory (lung) infections, asthma, and other respiratory disorders. Asthma has been shown to be three to four times more common among people with obesity (8).

More than half of those affected by obesity (around 50 to 60 percent) have obstructive sleep apnea (OSA). In cases of severe obesity, this figure is around 90 percent (7). OSA is a very serious breathing disorder. It occurs when extra fat in the neck, throat, and tongue block air passageways during sleep. This blockage causes apnea, which means a person stops breathing for a time. A person with OSA may have hundreds of apnea episodes each night. Apnea episodes reduce the amount of oxygen in a person’s blood. 

OSA may lead to high blood pressure, pulmonary hypertension, and heart failure. OSA can cause sudden cardiac death and stroke. Because apnea episodes interrupt the normal sleep cycle, you may not reach restful sleep. This can lead to fatigue (tiredness) and drowsiness. If untreated, this drowsiness may raise your risk of motor vehicle accidents.

Cancer

Cancer affects more than half a million lives per year in the United States alone. Obesity is believed to cause up to 90,000 cancer deaths each year. As body mass index (BMI) increases, so does your risk of cancer and death from cancer. These cancers include:

• Endometrial cancer

• Cervical cancer

• Ovarian cancer

• Postmenopausal breast cancer

• Colorectal cancer

• Esophageal cancer

• Pancreatic cancer

• Gallbladder cancer

• Liver cancer

• Kidney cancer

• Thyroid cancer

• Prostate cancer
• Non-Hodgkin’s lymphoma
• Multiple myeloma 
• Leukemia

For people with severe obesity, the death rate increases for all types of cancer. The death rate is 52 percent higher for men and 62 percent higher for women (9).

Cerebrovascular Disease and Stroke

Obesity puts a strain on your whole circulatory system, which carries blood through your body through your vessels (arteries and veins). This strain increases your risk for stroke and vessel damage in the brain. Obesity can lead to other stroke risk factors. Stroke risk factors include heart disease, hypertension, high cholesterol, type 2 diabetes (called metabolic syndrome when someone has three or more of these diseases) and obstructive sleep apnea (10).

Gastroesophageal Reflux Disease (GERD)

Gastroesophageal Reflux Disease (GERD), or heartburn, causes stomach acid or intestinal secretions to damage your esophagus. Common GERD symptoms include heartburn, “indigestion”, throwing up food, coughing (especially at night), hoarseness, and belching. Nearly two of every 10 people experience GERD symptoms regularly.

Obesity has been associated with higher risk of GERD, inflammation of the esophagus and rarely, esophageal cancer (11).

Bone/Joint Damage and Accidents

Obesity contributes to bone and joint issues. These issues can increase the risk for accidents and personal injury. Bone and joint issues can include: 

• Joint diseases (arthritis)

• Disc herniation

• Spinal disorders 

• Back pain

• Pseudotumor cerebri, a condition increasing the pressure in the brain and associated with confusion or disorientation, headache, and visual problems.

Other Conditions

• Alzheimer’s Disease: Studies find that obesity during middle-age may contribute to conditions that increase the risk for diseases that affect your memory and ability to think clearly – dementia and Alzheimer’s disease – later in life (12).
• Kidney Disease: High blood pressure, Type 2 diabetes and congestive heart failure are major causes of kidney disease and kidney failure. These conditions are caused or made worse by obesity.
• Liver Disease: Obesity is the major cause for fatty liver and non-alcoholic liver disease. Most people with severe obesity have fatty liver disease. Fatty liver disease can cause scarring of the liver, resulting in worsened liver function, and this can lead to cirrhosis and liver failure.
• Other conditions that could become life-threatening: Diabetes and high blood pressure during pregnancy increases the chance of a woman having a miscarriage, gallbladder disease, pancreatitis, and more.
• Other conditions resulting in diminished quality of life: stress urinary incontinence (leakage), enlarged ovaries causing infertility (inability to get pregnant), and skin fold rashes.


Obesity can have a dramatic impact on your body. The conditions related to obesity can be detrimental to your health. However, many of these complications can be avoided or cured through weight loss. 

References

1. Guh DP, Zhang W, Bansback N, et al. The incidence of co-morbidities related to obesity and overweight: a systematic review and meta-analysis. BMC Public Health. 2009; 9:88
2. Mulnier HE, Seaman HE, Raleigh VS, et al. Mortality in people with Type 2 diabetes in the UK.  Diabet Med. 2006 May;23(5):516-21
3. Wilson, Peter WF, et al.  Overweight and obesity as determinants of cardiovascular risk: the Framingham experience.  Arch Int Med  2002;162(16): 1867-1872.
4. Landsberg, Lewis, et al. “Obesity‐related hypertension: Pathogenesis, cardiovascular risk, and treatment—A position paper of the The Obesity Society and the American Society of Hypertension.” Obesity 21.1 (2013): 8-24.
5. Jensen, Michael D., et al. 2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults. J Am Coll Cardiol (2013).
6. Curtis, Jeptha P., et al. “The obesity paradox: body mass index and outcomes in patients with heart failure.” Archives of internal medicine 165.1 (2005): 55-61.
7. Drager, Luciano F., et al. “Obstructive sleep apnea: a cardiometabolic risk in obesity and the metabolic syndrome.” Journal of the American College of Cardiology 62.7 (2013): 569-576.
8. Camargo, Carlos A., et al. “Prospective study of body mass index, weight change, and risk of adult-onset asthma in women.” Archives of Internal Medicine 159.21 (1999): 2582-2588.
9. Calle, Eugenia E., et al. “Overweight, obesity, and mortality from cancer in a prospectively studied cohort of US adults.” New England Journal of Medicine 348.17 (2003): 1625-1638.
10. Chen, Hsin-Jen, et al. “Influence of metabolic syndrome and general obesity on the risk of ischemic stroke.” Stroke 37.4 (2006): 1060-1064.
11. Hampel, Howard, Neena S. Abraham, and Hashem B. El-Serag. “Meta-analysis: obesity and the risk for gastroesophageal reflux disease and its complications.” Annals of Internal Medicine 143.3 (2005): 199-211.
12. Kivipelto, Miia, et al. “Obesity and vascular risk factors at midlife and the risk of dementia and Alzheimer disease.” Archives of neurology 62.10 (2005): 1556-1560.
13. Onyike, Chiadi U., et al. “Is obesity associated with major depression? Results from the Third National Health and Nutrition Examination Survey.” American journal of epidemiology 158.12 (2003): 1139-1147.