Type 1 diabetes produces too little insulin

1. Type 1 diabetes occurs when the pancreas produces little or no insulin.
2. Without enough insulin body cells take in less glucose and the liver converts less glucose into glycogen.
3. Blood glucose remains too high especially after carbohydrate is digested and glucose enters the blood.
4. Control requires insulin delivered by injection or a pump because swallowing insulin would expose this protein hormone to digestive enzymes.
5. Dose and timing must be matched to food intake, activity and the measured blood glucose concentration.
6. Regular monitoring helps prevent blood glucose becoming dangerously high or falling too low after too much insulin.

Type 2 diabetes reduces insulin response

1. Type 2 diabetes occurs when body cells respond less effectively to insulin.
2. The pancreas can still make insulin but glucose uptake and glycogen formation do not increase enough.
3. Blood glucose remains high because glucose is removed from the blood more slowly.
4. Control often begins with lifestyle changes including a controlled carbohydrate intake, regular exercise and loss of excess body mass.
5. Medication may be needed when lifestyle changes do not control blood glucose adequately.
6. Risk is influenced by several factors including excess body fat, physical inactivity and inherited variation.

BMI relates mass to height

1. Body mass index is calculated using $\mathrm{BMI}=\frac{\mathrm{mass}(\mathrm{kg})}{[\mathrm{height}(\mathrm{m}){]}^2}$.
2. Mass must be in kilograms and height must be in metres before the values are substituted.
3. BMI estimates weight category but it does not distinguish between muscle mass and body fat.

Waist-to-hip ratio estimates fat distribution

1. Waist-to-hip ratio is calculated using $\mathrm{waist}:\mathrm{hip}\mathrm{ratio}=\frac{\mathrm{waist}\mathrm{circumference}}{\mathrm{hip}\mathrm{circumference}}$.
2. Both circumferences need the same unit so centimetres divided by centimetres gives a ratio with no unit.
3. A larger ratio indicates that more body mass is carried around the abdomen and is associated with a greater risk of type 2 diabetes.

Correlation does not prove cause

1. A positive correlation exists when the incidence of type 2 diabetes tends to increase as body mass or waist-to-hip ratio increases.
2. Correlation is evidence of an association but it does not show by itself that increased body mass directly caused diabetes in every person.
3. Other variables such as diet, physical activity, age and inherited variation may affect both body mass and diabetes risk.
4. Evaluation should consider the trend, the amount of variation, the sample size and whether important variables were controlled.

A glucose test can model urine screening

1. Glucose in urine may indicate that blood glucose has been high enough for glucose to remain in the filtrate instead of all being reabsorbed.
2. A chemical test can compare simulated urine samples for reducing sugar without handling human body fluid.

The result supports a diagnosis, not proves it

1. A positive simulated result shows that reducing sugar is present in that sample.
2. A real screening result would need confirmation with controlled blood glucose measurements and clinical assessment.
3. The strongest comparison links the result to insulin action while recognising that one observation does not identify the diabetes type.