Association and causation

Studying the incidence of disease in particular groups of people can lead tothe discovery of causation- what makes it occur. For example, the high incidence of lung cancer among cigarette smokers suggests that smoking is a causative factorin the development of lung cancer. However, care must be taken not to assume every association between a disease and a measured variable is causative.To say there is an association between two things simply means that they occur together in a certain situation. For example, several studies have indicated high rates of lung cancer in cooks. Although this could be a consequence of their work (perhaps caused by carcinogens in fumes from frying), it may be simply because professional cooks smoke more than the average. In other words, smoking might confoundthe association with cooking.

Exercises:

1. Complete the sentences. Look at A and B to help you.

1.The proportion of episodes of illness that end fatally is the …………….rate.

2. The proportion of people who die in a particular period is the ………..rate.

3. The proportion of babies born in a particular period is the ……………rate.

4. The proportion of patients who are still alive five years after treatment is the five-year…………..rate.

5. Ten per cent of the population have rhinitis at any time. This is the ………….

6. Every year, 0.5 – 1.0 % develop the condition. This is the………..

2. Complete the text, using the correct grammatical form of each word. Look at the table and at A, B and C to help you.

Incidence of lung cancer

In all countries, lung cancer was (1) …………in men than in women. The (2) …………incidence among men was in China where 67.5 men per 100.000 were diagnosed with lung cancer in the period. In women, however, lung cancer was less (3)…………in China than in the USA and Canada.

The (4)……….incidence in both men and women was in India. Sweden also had a fairly (5)……… incidence in both sexes. Lung cancer is probably (6)…………in India for cultural and economic reasons, whereas in Sweden it is the result of an effective health education campaign.

3. Find prepositions in A, B and C that can be used to make word combinations with the words in the box. Then use the correct forms of the words to complete the sentences.

1. Recent surveys showed that the ………..HIV cases had come down in the southern states of India.

2. Epidemiologic data suggest an ………..obesity and depression, but further studies and need.

3. Appropriate preventive measures should………a reduction in the mortality rate.

4. Thalasssaemia is ……….people of Northern European origin.

5. Male and female soldiers are equally………..post-traumatic stress disorder.