46. Research studies PROFESSIONAL ENGLISH IN USE FOR MEDICINE

PROFESSIONAL ENGLISH IN USE FOR MEDICINE

46. Research studies

A	Case-control studies Here are some extracts from a medical textbook. In a case-control study, a group of people suffering from a disease (the cases) is compared with a group who do not have the disease, but are similar in other ways (the controls). The two groups, the participants in the study, are compared to see if they were exposed to possible risk factor or not. A risk factor is something which may contribute to the cause of a disease.
B	Cohort studies In a cohort study, a group (cohort) of people (subjects) who are similar is studies over a period of years (a longitudinal study) to determine if there is a relationship between exposure to a risk factor and development of a disease. At the beginning a prospective study, none of the subjects has the disease. They are followed up for a number of years, and at the end of the period, those who have developed the disease are compared with those who have not. In a retrospective study, the researchers look back, by studying hospital records for example, at what has happened in the past, comparing subjects who have developed the disease with those who have not. In a cohort study and in a case-control study the subjects are only observed and there is no intervention such as drug treatment or surgery. A cohort study is a more reliable method of identifying the cause of disease than a case-control study. But for proof of cause, a trial is needed.
C	Trials In a trial, a group of people who are suffering from a disease are given a particular treatment. To determine the effectiveness of the treatment, a controlled trial is performed. Two groups are studied; one group (the study group) is given the treatment and the other (the control group) is not. The controls may be given a placebo – something which seems to be identical to the treatment but which has no effect. If there is an equal possibility that patients may be selected for the study group or for the controls, the trial is said to be randomized. A randomized controlled trial makes bias – error in a study which influences the results – less likely. An additional way of removing bias is blinding: patients do not know if they are receiving the treatment or the placebo. If, in addition, the researchers do not know who is receiving the treatment, the trial is double blind trial. Randomized controlled trials are used to test treatments or preventive measures.
D	Variables If the subjects in a study are all aged 50, then age is a constant in the study. If their ages range from 20 to 70, then age is a variable. A confounding variable is any variable which is associated with both the disease and the risk factor being studied (for example, smoking in the case of cooks and lung cancer discussed in unit 44). If such variables exist there is no way for the researcher to know whether the difference in the risk factor or the confounding variable is the one that is truly causing the disease.

EXERCISES

46.1	Complete the table with words from A, B and C above.
46.2	Complete the sentences with a word from A, B, C and D above. 1 People who are not receiving the experimental treatment, but who are otherwise the same as those receiving it are ______________. 2 A trial in which neither the subjects nor the researchers know who is receiving the treatment is a ______________ ______________ trial. 3 A study that follows the participants over many years is a ______________ study. 4 A ______________ is a group of people with similar characteristics.
46.3	Study the research questions below, and in each case decide which of the research study types mentioned in A, B and C above would answer the questions best. Use the index or a dictionary to look up any unfamiliar words.

Answer key