Type 2 diabetes develops when the body cannot use insulin properly, leading to chronically high blood glucose levels (BGLs), a condition called hyperglycaemia. Over many years, these high BGLs slowly damage blood vessels, nerves, and organs, leading to long-term complications.

Heart and blood vessel damage

Long-term high BGLs increase the risk of cardiovascular disease, atherosclerosis (narrowed, hardened arteries), stroke, peripheral artery disease, and chronic kidney disease. Damage to large and small blood vessels reduces oxygen supply to organs and limbs, which can cause heart attacks, leg pain when walking, poor wound healing, and a higher risk of death.

Nerve damage (neuropathy)

Persistently high blood glucose can damage nerves, a condition called diabetic neuropathy. This often begins with numbness, tingling, burning, or shooting pain in the toes, feet, fingers, or hands, and may gradually spread upward. Nerve damage can also affect digestion (causing vomiting, diarrhoea, or constipation), sexual function (such as erectile dysfunction), and blood pressure control, leading to dizziness and other symptoms.

Kidney and eye damage

High BGLs can damage the kidneys’ tiny filters, leading to chronic kidney disease and, in severe cases, kidney failure, sometimes requiring dialysis or a transplant. They can also damage blood vessels and lenses in the eyes, contributing to glaucoma, cataracts, and potentially visual loss or blindness if untreated.

Foot, skin, and mouth complications

Nerve and blood vessel damage in the feet can lead to loss of feeling, pain, ulcers, and infections. Even minor cuts can develop into serious infections, and in severe cases, amputation may be necessary. Diabetes also increases the risk of skin infections, mouth infections, and gum disease.

Bone and brain complications

People with diabetes have a higher risk of osteoporosis, which weakens bones and increases the likelihood of fractures. Poor long-term blood glucose control may also raise the risk of Alzheimer’s disease and dementia, possibly because brain cells cannot access the glucose they need, leading to cellular damage over time.