In this part of the Million Women Study, we are collecting blood samples so that we can include information from genetic and biochemical tests in our analyses. This is helping us to learn more about what makes someone susceptible to developing a disease.

What is the Disease Susceptibility Study? In this part of the Million Women Study, we are collecting blood samples so that we can include information from genetic and biochemical tests in our analyses. This is helping us to learn more about what makes someone susceptible to developing a disease.

The Million Women Study offers a unique opportunity to study the effects of these risk factors in depth because it is so large (nearly 1.4 million women are taking part) and because women have already given us such detailed information on the questionnaires about their use of medication and other lifestyle factors which may also affect disease risk.

For further information see the Detailed Investigation into Suseptibility of Disease on our Protocols page

Who is being asked to take part in the Disease Susceptibility Study? Not everyone in the Million Women Study is being asked to give a blood sample. We ask some who have reported having a specific illness, and others chosen at random. We have collected some 40,000 blood samples so far.

What does taking part involve? We write first to everyone invited to take part in the Disease Susceptibility Study, asking if they will consider giving a blood sample and filling in an extra questionnaire. Once we know who is interested, we write to their GP asking for help in taking the blood sample. With women in the Million Women Study living throughout the UK, we cannot set up special clinics to take samples and we rely on the goodwill of GPs and their practice staff. If the GP does not object, we then send more information, a consent form and a blood-sampling kit to the woman. She can then decide whether or not to go ahead and arrange for the sample to be taken at her GP surgery. There are no repeat samples – women need to have blood taken once only.

What happens to the samples? The blood samples are sent back to us, and processed in our laboratory in Oxford. They are separated into ‘buffy coat’ (containing white blood cells, which contain the DNA used for genetic tests) and serum (the liquid part of the blood left after processing, which contains hormones and other chemicals). The samples are stored in freezers at -80 degrees Centigrade. Part of the sample is being sent to a specialist collaborating laboratory, where DNA will be extracted and some genetic tests done. Samples will be stored for many years so that we can use them for a variety of tests, now and in the future.

Which tests will be done? Most of the tests will be genetic tests, comparing genes from women with a particular disease with genes from women without the disease. We can then see whether some genes are associated with a specific disease. We will also be able to look at the joint effect of genes together with other risk factors; and to include some biochemical tests. Information from a woman’s blood sample will be put together with information from her questionnaires and with information we may request from GP or hospital medical records, or from other NHS records such as disease registries.

Genetic testing is a very rapidly developing field. It is not possible to say now exactly which tests it will be possible, or useful, to do in a few years’ time. This is why we ask women to give their blood sample to the study as a gift, for us to test as we think most useful as the study progresses.

Are women told the results of the tests? We do not send women or their doctors the results of the genetic or other tests. This is because the meaning of the test results will not be clear at this stage. Our tests will be research tests, which are not the same as those a doctor might do. The final results of the study will of course be published and will be available on the study website. We advise anyone concerned about their susceptibility to disease to contact their own doctor.

How are my blood sample and personal information kept safe? As with every part of the Million Women Study we assure every woman taking part in the Disease Susceptibility Study that we will keep her personal information, and in this case her blood sample, absolutely confidential and will use it for medical research only. We are registered under the Data Protection Act.

The blood samples are stored, transported and tested, identified only by a code number. This number is different from the Million Women Study ID number used to identify questionnaire information, and the link between the two is held securely (and not as part of either database). All analyses are done at the co-ordinating centre in Oxford using data from which all identifying information has been removed.

Regulatory approval The Disease Susceptibility Study has ethical approval from Cambridgeshire 4 Research Ethics Committee (formerly Eastern Multi-centre Research Ethics Committee) (REC reference number 03/5/071) and Research Governance approval from all relevant Primary Care Trusts and Scottish Health Boards. The study is listed as study ID 3795 on the NHS UK Clinical Research Network Primary Care portfolio.