Conditions

Obesity is a medical condition characterised by excessive body fat that increases the risk of cardiovascular disease, diabetes, and other health problems. It is usually assessed using body mass index (BMI).

Oesophageal atresia is a rare birth defect that affects a baby's oesophagus (the tube through which food passes from the mouth to the stomach).

Find out about oesophageal cancer, including what the symptoms are, what causes it and how it's diagnosed and treated.

Oral thrush is usually harmless. It's common in babies and also older people with dentures. It can be treated with antifungal medicine.

Orf is a skin infection you can get from infected sheep or goats. It most often affects the fingers, hands, forearms or face. It usually clears up without treatment in about 6 weeks.

Osteoarthritis is a condition that causes joints to become painful and stiff. It's the most common type ofarthritisin the UK.

Osteomyelitis is a painful bone infection. It usually goes away if treated early with antibiotics. It can cause serious long-term problems if it's not treated.

Osteophytes (bone spurs) are bony lumps that grow on the bones in the spine or around joints. They form when a joint or bone has been damaged by arthritis, but do not always cause problems.

Osteoporosis is a health condition that weakens bones, making them fragile and more likely to break. It develops slowly over several years and is often only diagnosed when a fall or sudden impact causes a bone to break (fracture).

Otosclerosis is a problem with the bones inside the ear which causes gradual hearing loss. Hearing aids or surgery will usually improve your hearing and total hearing loss is rare.