01 · Biomedical map
Type 1 and Type 2 diabetes
High blood glucose often shows up on a test before you feel unwell. Diabetes mellitus is a disorder of insulin: when insulin is missing or cannot work well enough, glucose rises and stays in the blood.
Insulin deficiency, or a mix of deficiency and tissue resistance, leaves sugar circulating instead of entering cells. The two common clinical pictures differ in how that failure starts.
| Type | What happens | Who it often affects |
|---|---|---|
| Type 1 diabetes | Near-complete insulin deficiency after the immune system damages insulin-producing cells in the pancreas. | Can appear at any age; most often diagnosed in juveniles. Family history can sit in the picture. |
| Type 2 diabetes | Body tissues resist insulin, and the pancreas cannot make enough extra insulin to overcome that load. | Later onset, usually after age 40, especially with overweight and inactivity. About 90% of people with diabetes in Singapore have Type 2. |