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Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.
The key difference
Type 1 diabetes is an autoimmune condition where the pancreas cannot produce insulin: treated with insulin injections. Type 2 diabetes is a lifestyle-related condition where body cells become resistant to insulin: managed with diet, exercise, and medication.
Both types of diabetes result in poorly controlled blood glucose levels, but they have different causes, different age profiles, and different treatments. The IGCSE syllabus requires you to distinguish between them clearly: a common 4-mark comparison question.
Feature
Type 1 Diabetes
Type 2 Diabetes
Cause
Autoimmune destruction of beta cells in the pancreas: the body attacks its own insulin-producing cells
Body cells become resistant to insulin / pancreas may produce less insulin over time
Insulin production
No insulin produced
Insulin is produced but cells do not respond to it properly
Age of onset
Usually diagnosed in childhood or adolescence
Usually develops in adults (over 40), but increasingly seen in younger people
Risk factors
Genetic predisposition; not linked to lifestyle
Obesity, lack of exercise, high-sugar diet, genetic predisposition, age
Treatment
Insulin injections (daily) and blood glucose monitoring
Diet control (reduce sugar / refined carbohydrates), exercise, weight loss, and sometimes medication
Preventable?
No: cannot be prevented
Often preventable through healthy lifestyle choices
Proportion of cases
About 10% of diabetes cases
About 90% of diabetes cases
Why Type 2 Diabetes Is Increasing Globally
Type 2 diabetes has become a global health concern. The main reasons for the increase are:
Rising obesity rates: excess body fat, particularly around the abdomen, increases insulin resistance
Sedentary lifestyles: lack of physical activity reduces the body's sensitivity to insulin
Diets high in sugar and refined carbohydrates: these cause frequent blood glucose spikes, putting strain on insulin-producing cells
Ageing populations: insulin resistance naturally increases with age
How Insulin Injections Work
People with Type 1 diabetes must inject insulin because their pancreas produces none. The injected insulin performs the same function as natural insulin: it allows body cells to take up glucose and signals the liver to convert excess glucose to glycogen. Patients must carefully balance their insulin dose with their food intake and activity levels to avoid:
Hyperglycaemia (blood glucose too high): if not enough insulin is injected
Hypoglycaemia (blood glucose too low): if too much insulin is injected or a meal is missed
Try a comparison question (4 marks)
Compare the causes and treatments of Type 1 and Type 2 diabetes. [4]
Show the answer and marking guidance
Type 1 is caused by autoimmune destruction of beta cells so no insulin is produced; Type 2 is caused by cells becoming resistant to insulin
Type 1 is not linked to lifestyle; Type 2 is often linked to obesity and lack of exercise
Type 1 is treated with insulin injections; Type 2 is managed with diet, exercise, and sometimes medication
Type 1 cannot be prevented; Type 2 can often be prevented through lifestyle changes
Original Cambridge-style practice written for this site.
Common comparison mistakes
When answering a compare question, write matched pairs rather than two separate descriptions.
Saying Type 2 diabetics "don't produce insulin": they do produce insulin, but their cells are resistant to it
Claiming Type 1 diabetes is caused by eating too much sugar: it is an autoimmune condition
Confusing the treatments: insulin injections are for Type 1; diet and exercise management is the primary approach for Type 2
Forgetting that Type 2 diabetes has a genetic component as well as lifestyle factors