What are cohort studies and why are they important?
We spoke to people who had taken part in or been invited to join cohort studies. The term 'cohort study' was often unfamiliar and could...
Being asked or volunteering to take part in cohort studies
Apart from those who had started the study when they were babies or young children, most of the people we interviewed could remember being invited or volunteering to join their cohort studies but they could not always remember the details about the information given or the consent process. For some, this was because they enrolled in a study a long time ago. Sometimes the experience of being invited and agreeing to take part was not very memorable. As Anthony said, ‘They may have explained but a lot of these things don’t stick in your mind, you know, I can remember the more important things in life, but, [laughs]’.
Those who started a study when they were babies or young children hadn’t been involved in making the decision to enrol. Instead, this decision was made by their parents. Some thought that the researchers had probably asked their permission again at a later date and as they got older, but often they couldn’t remember this happening for certain. A number of people we talked to only became aware that there were/are part of a birth cohort study when they were contacted by researchers many decades later. As Derek explained, ‘Prior to that, I wasn’t aware I was part of any study at all’.
Keith received a letter about a renal (kidney) study via his GP. He met with the researcher to discuss it and to sign some forms.
Anne can’t remember joining a birth cohort study, and it was many years later that she received some information in the post from the researchers.
Isobel isn’t sure why she was selected to join a birth cohort study. She attended a meet-up a few years ago, but doesn’t remember taking part as a child or completing any study activities as an adult.
Being invited or volunteering to join a study
Of the people we interviewed who could remember being asked to join a cohort study, there were different ways that they were first approached. Sometimes people were invited through their GP medical practice, either by letter or in person or they had seen an advert in the practice and had volunteered. Other times, people were asked in hospital when they were attending an appointment or as an inpatient after being diagnosed with a medical condition. John was invited to join a research study about transient ischaemic attack (TIA, ‘mini stroke’) and stroke whilst he was in hospital, and he ‘was delighted to do so’. Sometimes people had seen an advert, poster or leaflet looking for volunteers, which they had responded to. Luke saw a television programme which mentioned a twins study and he contacted the researchers to ask about joining.
James was invited to a study through his GP after having a transient ischaemic attack (TIA). He agreed because it helped give him quicker access to a specialist clinic and team of professionals.
Elaine received a letter in the post to invite her to join a cohort study. She was already involved in medical research and the timings didn’t work out.
Others did not know or could not remember how they were invited to join their study. Emily has taken part in a few medical studies and couldn’t recall how she was first invited or volunteered for each. Some people, like Gill, were already involved in another medical research study or had indicated they would be interested in future research, and they thought this might be why they were invited to join a cohort study. There are strict rules about how personal data can be shared, meaning it was unlikely, but Gareth wondered if the research team contacted him because he was a regular blood donor and ‘I don’t know whether they share lists’.
Salma enrolled herself and her unborn child into a cohort study after she was approached by a member of the research team whilst waiting in hospital for a test.
Alan Y was approached about taking part in a cohort study whilst recovering from a transient ischaemic attack (TIA) in hospital.
Mr S and his wife, who was pregnant at the time, were approached about a birth cohort study. He had seen posters about the study before, but didn’t know too much about it.
Getting information and asking questions about the study
Although the details were hazy, most people we talked with were sure they had received adequate information about the study before or at the time that they were asked to join. There was usually some written information, such as a leaflet that arrived in the post or was handed out by a healthcare professional. Some people, like Mr S and Alan Y, had met a member of the research team or spoken to them on the phone to find out more about the research and what would be involved in taking part.
Most people were happy with the information they had received about the study early on. Nadera felt the written information was ‘very simple which is a good thing’. Some found the language was too medical, but this varied between studies and for different individuals. Sometimes study leaflets were available in languages other than English, or there were research staff and translators who could speak other languages. This wasn’t always the case though, and Iram would have preferred information about the study to be available in Pashto. A few people felt the information they were given was too vague, either it hadn’t been explained clearly and in way they could understand, or because they felt the researchers were unsure at that stage how the data would be used. Malcolm recognised that not everyone wants lots of detail and ‘it all very much depends on the individual’.
Compared to the awful paperwork for brain donation, Roland found the information leaflet about a biomarker study easy to understand.
For Emily, the interesting part of the information leaflet is about the purpose of the study. The other paperwork is all the standard stuff.
Emily has taken part in a number of medical studies. She thinks the specifics of the study should be clearer in the written leaflets, and then she could skim the more generic material. She also thinks the documents need to be carefully proofread.
Speaking to a member of the research team was often welcomed as an opportunity to ask questions. Gareth felt the written information was quite medical and ‘I didn’t feel it was enough for me to make the decision on my own’. He was ‘fortunate’ to have some relatives who had worked in medical research and asked them for their advice when deciding whether to take part. He took these questions to his first meeting with the researchers. For Alan Y, ‘The most important thing was this part of the question-and-answer and being able to actually talk to someone, rather than read it’. However, Linda cautioned that not everyone would feel confident asking questions. She said some people ‘might feel intimidated and don’t want to ask because, of embarrassment or feeling inadequate or silly’.
Alan Y doesn’t remember a lot about the information he initially received but recalls that it was helpful to discuss with a member of the research team in person soon afterwards.
Malcolm received a letter about a study and then went to talk to a researcher with a medical background.
Salma was given a leaflet and spoke with a research nurse about a study. She felt comfortable asking questions and the researchers are a very friendly team.
Completing paperwork and giving consent
Some people could remember completing some paperwork when they joined a cohort study. Keith said, ‘The decision was made instantly,’ to take part and he signed some forms to enrol in the study when he met with a researcher. Mr S and his wife were approached by research staff whilst waiting for an appointment and so ‘we had the time’ to complete the paperwork. Malcolm couldn’t remember exactly what had been on the form when he agreed to take part in a study but thought there would have been topics like data sharing as ‘one of the questions in the tick boxes’.
For Luke, trying to pinpoint exactly when he joined’ a twins study raises interesting questions. He completed paperwork but highlights that the data he provides is about his past, current and future self.
A few people who had been in a birth cohort study for many decades, like Teresa and Linda, thought that the process of giving consent was different when their parents were asked to enrol them. As Linda said, ‘I dare say my parents got a consent form’. Isobel thought that many decades ago, ‘there never would have been a discussion with the children, the discussion would have been with the teachers and your parents’. She wasn’t sure if her parents were even asked their permission and thought maybe it had been a school decision. Teresa agreed that the approach now was different and felt that it could be excessive: ‘That’s of the time really isn’t it, I mean it’s only now when it’s become a little bit ponderous where it’s checked and checked and checked’.
Barbara’s parents agreed for her to take part in a birth cohort study. She thinks their willingness to enrol her was reflective of the attitude towards research at that time.
For some of the people we interviewed who were babies or children when they first took part in a cohort study, there was a point later on when they were asked by the researchers whether they still wanted to take part and to ‘re-consent’. A few people felt their continued participation in the research was an unspoken way of them re-consenting, they felt that if someone didn’t want to continue anymore, they could simply stop responding to the researchers.
Luke felt that giving ‘long-term or opened ended consent’ in a study like his was quite complicated. He pointed out that the researchers themselves don’t know how they might use his data in future years, and so he questioned how it was possible to give ‘informed consent’. He also highlighted that although his twin brother agreed to enrol, it was as ‘a favour’ to Luke and there can be ‘asymmetries between the pairs’ in terms of keenness to take part and complete the research activities in twins studies.
As an adult, Barbara thinks that each time she chooses to return a questionnaire or arrange a visit is a kind of re-consenting’ to the research.
Jade took part in a twins study from a young age. She thinks it’s important to check that a child is happy to continue as they grow older and are able to understand more.
Brian can’t remember a re-consenting process in his birth cohort study and doesn’t think it was particularly necessary because he was involved already and never thought of not doing it.
Sometimes people had kept paperwork about the studies they were part of, but often this paperwork had been thrown out or lost. Sometimes this was a major concern, as for Lucy who felt frustrated by her lack of knowledge about the study she had been in. Iram and Rafi weren’t given copies of their paperwork; at the time, they didn’t mind but ‘after a few years, you’re thinking ‘Oh I should have the copy”. Others were not concerned. Some people, like Jade, had looked online and found information about the study and study team, including contact details if they wanted more information.
When Mr S and his wife were invited to join a study, one of the research team confirmed they were happy to take part in Urdu.
Why take part in cohort studies?
People take part in cohort studies for a number of reasons. These types of studies often involve a long-term commitment, even if the actual time...