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Diabetes 16+

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Diagnosis of diabetes

Type 1 diabetes

The onset of type 1 diabetes is rapid and its symptoms are likely to be noticed through:

  • Excessive thirst
  • Weight loss
  • Drowsiness
  • Coma, in extreme cases
  • Blood glucose level above 10 millimoles per litre (mmol/l).
  • Muscle cramps
  • Gastrointestinal symptoms such as nausea and vomiting, abdominal pain and changes in bowel movements
  • Diabetic ketoacidosis (DKA)
  • Polyuria (excessive urine production)
  • Urinary tract infections


Type 2 diabetes

This form of diabetes develops much more gradually and so symptoms may not be apparent for many years. It is often diagnosed during healthy screening tests where the blood sugar level is found to be elevated despite there being no symptoms of diabetes.

A simple test strip can indicate the presence of glucose in the urine. Image courtesy of: Wellcome Images

Oral Glucose Tolerance Test (OGTT)

Simple blood and urine tests may be sufficient to diagnose diabetes in some people. Others may have to take an oral glucose tolerance test (OGTT) if other blood and urine tests are inconclusive.

Patients are not allowed to eat for at least 12 hours before the test. A blood sample is then taken to measure the patient's fasting blood glucose level.

They are then given a drink containing 75g of glucose. This is quickly absorbed and their blood glucose level is measured over the next two hours.



Plasma venous glucose concentrations used for diagnosis of diabetes:

  Concentration (mmol / l)
  Fasting ≥ 7
  2 hours post-glucose ≥ 11.1
Glucose Test Diagnostic



Individuals with diabetes rapidly become hyperglycaemic and their blood glucose level remains above normal. Blood glucose in the person with diabetes rises and stays above normal.

Healthy individuals will release insulin to store the excess glucose and return their blood glucose level to normal. The healthy person regulates their glucose back to normal.

Question 3

In the UK, there are significant variations in the frequency of type 2 diabetes between different population groups.

Look at the graph and answer the question.

Rates of diabetes in different ethnic groups in England


The graph shows the incidence of diabetes in adults over the age of 16 from different population groups (type 1 plus type 2). Describe the likely factors that influence the different rates of diabetes. Suggest how these factors could be further investigated.

Factors may be:

  • Most groups exhibit greater rates than when the population as a whole is considered.
  • Women are generally less likely to have diabetes than men are. However Pakistani women have a higher rate of diabetes than Pakistani men.
  • Genetic differences are likely to be a major contributing factor. Black Caribbean, Pakistani, Indian and Bangladeshi groups all have high levels of diabetes. Chinese, Black African and Irish are closer to the population average.
  • Diet could play a part, as ethnic groups may have different diets.
  • As families relocate from Asia to Europe, their lifestyle and diet may change to ones that increase the risk of developing diabetes.

Further investigations could include:

  • Genetic screening of families where someone has diabetes could lead to the identification of family members who have genes that make them susceptible to diabetes.
  • Analyse the diets of groups / families that have a higher incidence of diabetes. E.g. what proportions of diet is high in fat, sugar etc. Compare with groups that have a lower incidence.
  • Investigate lifestyle - activity, obesity etc.
  • Look at incidence of diabetes in regions where groups originated. Is the incidence of diabetes the same or different? If different, look for differences in diet and lifestyle that could explain the change in incidence.