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Prevalence of beliefs about actual and mythical causes of cancer

By Jo Waller, on 26 April 2018

Lion Shahab, Jennifer A. McGowan, Jo Waller, Samuel G. Smith

Approximately one third to one half of cancer diagnoses are preventable by changes to lifestyle behaviours. In Europe, at least 1.1 million cancer cases per year could be prevented if people had healthier lifestyles. According to the latest (4th) European Code Against Cancer (ECAC), established cancer risk factors include active and passive smoking, alcohol consumption, being overweight or obese, being physically inactive, have a poor diet, being exposed to ultraviolet radiation (e.g. from the sun), and infection with human papillomavirus (HPV). However, many other unverified (‘mythical’) causes of cancer appear in tabloids and on social media. Recognising the difference between the real and the ‘mythical’ cancer causes can be difficult. Conflicting messages can make it harder for people who are trying to reduce their cancer risk to place their efforts into effective activities.

In a study published in the European Journal of Cancer, we report findings from the 2016 Attitudes and Beliefs About Cancer-UK Survey of 1,330 UK participants. The survey explored the public’s beliefs about actual cancer causes (smoking, alcohol consumption, low physical activity, low fruit and vegetable consumption, being overweight) and mythical causes of cancer. Awareness of actual causes of cancer was low, with participants on average on being able to identify half of the causes of cancer. More than a third (40%) of adults did not know that being overweight was associated with an increased cancer risk and the same number did not recognise sunburn as a cancer risk. Almost three in four adults (71%) did not know that HPV is associated with cancer. Being able to identify correct causes of cancer was related to the likelihood of participants not smoking, and eating five or more fruit and vegetables a day.

Participants could, on average, only identify 36% of mythical causes of cancer as incorrect. Of these, adults were most likely to believe that stress (43%), food additives (42%) and electromagnetic frequencies (35%) caused cancer. A quarter (26%) of participants believed that mobile phones could cause cancer. Interestingly, adults who endorsed the actual causes of cancer were also more likely to also believe in the mythical causes, suggesting a great level of confusion between the two.

If people are to make informed decisions about their lifestyle they need an accurate understanding of cancer risk factors. Our survey shows that there is a large degree of confusion among the general public regarding those risks. It seems that the numbers of people who believe in the unfounded causes of cancer has increased over the last decade. This could be linked to the way people now access information and the rise of so-called “fake news”. Looking for information from reputable websites like NHS Choices and Cancer Research UK is a good way to avoid this. Cancer Research UK even has a page presenting evidence to debunk some the myths, which could be a useful resource for people who are understandably confused.

Why do some parents choose not to vaccinate against HPV?

By rmjdlro, on 16 March 2017

What is HPV?

Human papillomavirus, also known as HPV, is a common virus that affects the skin and moist areas that line the body, such as the cervix. It is spread by skin-to-skin contact and can be transmitted through sexual activity. Most people will come into contact with HPV at some point in their life, and in most cases the body will get rid of the virus on its own. However, in some cases the virus can cause cell changes which can increase the risk of some cancers, such as cervical cancer. There are over 100 different types of HPV, but two types in particular (types 16 and 18) cause 70% of cases.

In 2008 a vaccination was introduced which protects against these two types of HPV. It also protects against two other types of HPV that don’t cause cancer, but do cause genital warts. The vaccination is mainly given through schools to girls aged 12-13 (in school year 8). The vaccine is given in two separate injections.

Why was this study done?

Most girls get the vaccination but as we’ve written before, there are some girls who do not. Research has shown that girls from ethnic minority backgrounds are less likely to have the vaccination than White British girls. In our new study, published this week, we investigated why this might be the case.

What did we do?

We did thirty-three face-to-face interviews with parents from ethnic minority backgrounds, whose daughters both had and had not got the vaccine. We also did interviews with parents from White British backgrounds, whose daughters had not got the vaccine, so that we could see whether there were any differences between what parents from different ethnic backgrounds were saying. All but one of the people we interviewed were mothers.

What did we find?

Parents have concerns about the vaccine

Parents had concerns about side effects of the vaccine and its effectiveness, despite the vaccine being recognised as safe by the UK government and World Health Organisation. Some parents were worried that the benefits of having the vaccination might not outweigh the risks. Other parents worried that it might encourage girls to be more sexually active.

Other people’s opinions and experiences are important

Some parents’ vaccination decisions were affected by things they had heard from other people about the vaccination. A number of parents had got information from others about the vaccine and some parents had heard about girls who happened to become unwell after having the vaccine and whose parents thought this must have been caused by the vaccine.

Parents need more information

Many parents had not heard about the vaccine before their daughter was invited to have it. Some parents felt like they had not been provided with enough information about the vaccine and others chose to research it themselves.

 Some parents prefer to protect their daughters using other methods

Although there isn’t any evidence that complementary medicines can prevent HPV, some parents preferred to use them instead of vaccination and some encouraged a healthy lifestyle to prevent illness. Others thought that better ways to prevent their daughter from getting an HPV infection would be to encourage them to have safe sex, to educate them about sex or for their daughters to not have sex before marriage. A few parents believed illness was caused by things outside their control, such as God.

Some parents don’t trust authorities

A number of parents believed that the introduction of the vaccine was driven by pharmaceutical companies wanting to make money. Some of these parents lacked faith in the government and why it had chosen to introduce the vaccine.

Emotions influence vaccination decisions

Some parents felt that they might regret the decision if they vaccinated, whilst others felt they might regret their decision if they did not.

What did we conclude?

In general, many of the things parents spoke to us about were said by parents from all different ethnic backgrounds. However, there were some issues that were only brought up by parents from ethnic minority backgrounds. These included preferring their daughters to wait until marriage before having sex and believing that cervical cancer is caused by things that are out of their control.

The results of this study suggest to us that any future attempts to try and increase uptake of the vaccination need to consider issues that are important to parents from ethnic minority backgrounds. It may be helpful to involve community group leaders and religious leaders when designing future interventions, to ensure that it is appropriate and well considered.

 

Positive emotions and exercise: Developing an app to increase physical activity

By rmjdlro, on 28 February 2017

Mobile phone apps are commonplace in today’s society and for millions of people they are a part of everyday life. In 2016 alone, worldwide downloads exceeded 90 billion1. Apps tracking calorie consumption, exercise, steps, food points and so on, have become increasing popular. Physical activity apps in particular, have been shown to be effective in increasing people’s levels of physical activity2-3. However, most physical activity apps are tailored towards those who enjoy recording information about their performance and/or enjoy the competitive element offered by most fitness apps. Currently there are no physical activity apps which focus on the pleasure that someone might experience from doing the activity itself.

In our new study, published this week, we aimed to develop a physical activity app that would allow users to record positive images and feelings about the activity they performed, whether that was walking the dog or going to the gym, as well as encouraging them to make it a habit. We reasoned that linking positive feelings to a particular activity would increase the likelihood that the user would perform the activity more frequently, which would make it more likely to become a habit.

The app (‘Haptivity’) allowed users to take a photo every time they carried out an activity, to remind them of any positive feelings they had. Then, at a specific time each day the user would receive a reminder to be active, coupled with a photo that the user had previously uploaded. Each time users were active they would be prompted to take another photo. Users were able to look at these photos any time they liked and could receive positive feedback from other app users who they had connected with.

App 1 app 2 app 3

 

 

 

 

 

 

 

 

 

 

The app was developed along with a group of participants who helped to design and test it. Participants were aged 35-55 and said that they didn’t do any exercise at the moment, but would like to be more active. Participants initially attended a meeting to discuss what they wanted and needed in apps in general and in physical activity apps specifically. A few months later participants attended a second meeting where they were asked to download the app and to discuss their initial thoughts. At this point they were asked to complete a questionnaire about how much physical activity they were currently doing and other psychological factors related to physical activity. Participants then went away and tested the app in their own time before returning for a final meeting where their experience of using the app was discussed and they were asked to complete the same questionnaire again. This was to assess whether there had been any change in their physical activity levels whilst they were using the app, although it is important to point out that the aim of the study was to develop the app, not to increase physical activity levels at this point.

The feedback provided by participants was generally positive and suggested that it motivated them to be more active, although they had suggestions as to how to improve the app, such as being able to quantify the activities performed (e.g. recording time spent doing an activity) and being able to make the photos more interesting using photo editing, for example. Small improvements were seen in the amount of time people spent walking, although there were also reductions in the amount of time spent performing activities at a moderate and vigorous level of exertion. Overall, participants thought that the app was acceptable although it will need to be developed and tested further, with a larger number of participants, to incorporate their suggested changes.

1 App Annie 2016 Retrospective – Mobile’s Continued Momentum. https://www.appannie.com/insights/market-data/app-annie-2016-retrospective/

2 Foster, C., J. Richards, et al. (2013). Remote and web 2.0 interventions for promoting physical activity. Cochrane Database of Systematic Reviews, 9, CD010395.

3 Richards, J., M. Hillsdon, et al. (2013). Face-to-face interventions for promoting physical activity. Cochrane Database of Systematic Reviews, 9, CD010392.

 

Welcome to the new Research Department of Behavioural Science and Health

By Moritz P Herle, on 23 January 2017

Today marks an exciting new chapter in the history of the Health Behaviour Research Centre. Since its inception as the Health Behaviour Unit at the Institute of Psychiatry in 1996, the group has grown into the world class Health Behaviour Research Centre at UCL and now merges with the Psychobiology group to form the Research Department of Behavioural Science and Health.

The mission of the Research Department of Behavioural Science and Health is to apply the whole range of behavioural sciences (including health, social and cognitive psychology, aetiological and health care epidemiology, psychobiology, exercise science, behaviour genetics, dietetics, communication sciences, and health services research) to a better understanding of disease prevention, early detection, and prognosis.

Our vision is to carry out cutting-edge research and provide high quality teaching on the impact of behavioural and emotional processes on disease aetiology and health outcomes, and to implement this knowledge to reduce disease risk and improve the health of the population.

More information about the Department can be found on our brand new website.

You can also follow us on Twitter via @ucl_bsh.

The official launch of the new Department will be celebrated at a later date (invitation only).

One more week until the launch of the new Department

By Moritz P Herle, on 16 January 2017

Regular readers of this blog post have already heard the exciting news: next week, the HBRC will merge with the Psychobiology group to form the new Research Department of Behavioural Science and Health.  More information about the new Department can be found in our previous blog post about it.

Stay tuned!

BREAKING NEWS: the HBRC is soon to become its own department

By Moritz P Herle, on 9 January 2017

Pssst, have you heard the news??  The Health Behaviour Research Centre is soon to become its own department!  After many months of preparations, we finally get to share this exciting news with you: on the 23rd of January, the Health Behaviour Research Centre will merge with the Psychobiology Group.  Both are currently located in UCL’s Research Department of Epidemiology and Public Health, but together they will form the new Research Department of Behavioural Science and Health.

What will change?

The head of the new Research Department of Behavioural Science and Health will be Professor Andrew Steptoe, who will be stepping down as Director of the Institute of Epidemiology and Public Health.  Andrew has led the Psychobiology group since its formation in 2000.  Professor Robert West, who currently leads the HBRC’s Tobacco and Alcohol Research Group, will become deputy head of the new Department.  Both will continue to lead their respective research groups within the new Department.

The HRBC’s “Cancer Screening and Communication” and “Energy Balance” groups will undergo some transformations.  The former will be split into two new research groups: the Cancer Communication & Screening research group, which will be led by Dr Jo Waller and Dr Christian von Wagner, and the Epidemiology of Cancer Healthcare and Outcomes (ECHO) research group, which will be led by Dr Yoryos Lyratzopoulos.

Similarly, the Energy Balance group will be split into two: the Obesity research group, led by Dr Clare Llewellyn and Dr Helen Croker, and the Energy Balance and Cancer research group, which will be led by Dr Becca Beeken and Dr Abi Fisher.

The HBRC and Psychobiology have always had a common interest in understanding how demographic, psychosocial and behavioural factors influence physical illness.  Historically, the HBRC has focused on cancer while much of the work of the Psychobiology group has been in the area of cardiovascular disease and ageing. There are considerable overlaps and synergies in the theoretical and methodological approaches taken, and we hope that the new Department will facilitate even closer links than ever.  Last July, the two groups spent a joint “Away Day” learning about each other’s research at the beautiful London City Hall, where the photo below was taken.

groupphotos

 

 

 

 

 

 

As part of the transition process, this blog will shortly be renamed “UCL Health Chatter: the Research Department of Behavioural Science and Health blog”.

In addition, if you follow us on Twitter, look out for the new name of our Twitter account (currently @hbrc_ucl).   From 23 January onwards, you can find us on Twitter as @ucl_bsh.  If you’re already following us, the name of our account will be automatically updated in your Following list.

What will stay the same?

Some things will never change, however.  We will continue our world-class research into the behavioural determinants of health and illness, as well as our education of the next generation of excellent behavioural health scientists via our doctoral research students and the MSc Health Psychology course.  Our visiting address will also remain the same, at 1-19 Torrington Place, London.

Why this change?

The creation of a new department is a demonstration of UCL’s ongoing commitment to outstanding research in behavioural science and health, and a recognition of the strengths we have in behavioural aspects of disease prevention, early detection, and prognosis. While some of our work is epidemiological, other research involves clinical and experimental paradigms, so is distinct from that of the Research Department of Epidemiology and Public Health.

We look forward to welcoming you to our new Department and website from 23 January onwards.

 

Remember, you heard it here first!

 

 


 

What we know about parents’ decisions about vaccines: Reviewing the research

By rmjdlro, on 30 August 2016

Vaccines help prevent infectious diseases. It is important that most people get vaccines and if enough people are vaccinated, protection is also given to people who have not been vaccinated. This is known as herd immunity. Even though most children do get the vaccines they are offered, there are still some areas in the UK where there have been outbreaks of disease.

In general, parents in the UK need to give permission for children under the age of sixteen to have a vaccination. Whilst many parents choose for their children to be vaccinated, some parents decide not to. It is important for us to understand why parents might decide not to vaccinate their children, so that we can address any issues that might be stopping parents from vaccinating. Only once we understand the reasons for non-vaccination can we start to think of ways to tackle them, to try and increase uptake of childhood vaccinations. The best way for us to find out what these issues might be is to review existing research in this field, much of which has been qualitative. Qualitative research aims to understand a topic by finding out people’s opinions, attitudes, motivations etc. This is often done by conducting interviews or focus groups.

In our review, published this week, we aimed to do just this; to look at qualitative studies in the UK that had looked at vaccines for children, to try to understand what might influence parents’ decisions about vaccination. We reviewed a total of 34 studies. The results of each of these studies were then re-analysed to find common themes between them.

We found that parents make decisions about vaccination in two different ways: some made decisions automatically, and others made more intentional decisions.

Automatic decisions

Automatic decisions are decisions that are made by parents without too much thought. When parents made these types of decisions they were often happy to go along with the advice about vaccination that was being given to them from health professionals. Parents also made automatic decisions when they did not feel like they had a choice and/or when they were copying the decisions other people had made about vaccinating their children. These types of decisions are often made quickly and parents did not appear to weigh up the pros and cons of vaccination when making them.

Intentional decisions

Intentional decisions are decisions that parents have taken more time to think about. When parents made these types of decisions they often weighed up what they perceived to be the risks and benefits of vaccinating and often judged how appropriate it was to vaccinate their child based on other people’s advice or experiences. Many parents making intentional decisions felt responsible and/or were worried about being judged by other parents for the decision they were making. Parents’ emotions had an effect when making intentional decisions, as did the media and what was being reported about vaccination.

Additional factors

The media affected the trust that parents had in information they received about vaccination, and in medical professionals, the government and the NHS. Trust (or a lack of trust) was important for parents when making both automatic and intentional decisions. Practical issues, for example travelling to the vaccination clinic, having a lack of time or being unable to get an appointment, also affected the decisions of parents who had decided to vaccinate, regardless of whether they had made an automatic or intentional decision.

What does this tell us?

Many parents who made automatic decisions had decided to vaccinate their child. However, some of these parents had decided to vaccinate because they felt pressured to do so. Other parents had copied other people and not vaccinated their child. Some parents who made intentional decisions had involved others in their decision-making, by speaking to family members, friends or work colleagues.

The findings of this review highlight how important social factors are for parents when making decisions about vaccinating their child. The impact of one child not having a vaccination may go beyond just that child being unprotected, as that decision may influence other parents’ decisions. By understanding more about the decisions parents make about vaccinating their children we will be in a better position to start to think of things we can do to encourage more parents to give permission for their children to have childhood vaccinations.

The importance of vaccination for everyone

By rmjdafo, on 19 August 2016

It’s important that most people get vaccines

Most people get the vaccines offered to them as part of the NHS immunisation programme. They help prevent, and reduce the spread of diseases. Because of vaccines we no longer have smallpox anywhere in the world and polio is almost wiped out too.

For some vaccines, fewer people from some ethnic minority backgrounds get them compared to everyone else in the UK. For example, children from Nigerian, White Polish or Somali backgrounds are less likely than other groups to be vaccinated against Diphtheria in London (1). For other vaccines, more people from some ethnic minority backgrounds get them compared to everyone else. For example, one study found that children from Black and Asian backgrounds living in the London borough of Brent had higher uptake of the first dose of the MMR vaccine than children from White backgrounds (2).

Because of the way vaccination works, it’s really important that most people get the vaccines they are offered. If enough people get vaccines, protection is given to the people who cannot get them for medical reasons or are too young. So although the vast majority of people get vaccines, it’s still useful to understand why some people do not, so we can work out how we might be able to increase the number of people who get them. Because of the differences in who is and is not getting vaccines, we decided to explore what it was that might make children from ethnic minority backgrounds more or less likely to get vaccines.

What did we do?

In our new review, we looked at published studies where parents from ethnic minority backgrounds have been spoken to about why they had or had not chosen to vaccinate their children. We just looked a studies that had used qualitative methods, like interviewing parents and speaking to small groups of parents all at once (called focus groups). We used a technique called Thematic Synthesis to bring all of the findings together, which involves a number of researchers labelling the things that people had said and finding common themes within these labels.

What did we find?

Not surprisingly we found that most of the things that had convinced parents from ethnic minority backgrounds to get vaccines for their children, or had stopped them from doing so, were the same as the things that parents in general tell us. For example, parents had said that they were happy to go along with the doctor’s recommendation; that their decision had been influenced by other people and had found that things like transport problems had stopped them getting vaccines.

But there were also some things that had affected parents’ decisions about vaccines that were linked to ethnicity. For some parents, their religion instructed them about whether vaccines were needed for their children. Other parents were influenced by their experiences of having lived in other countries. For some, this made them appreciate the healthcare that is offered in the UK, but others felt that particular vaccines were not needed because they were not offered to them back home. Scare stories in newspapers or on the television can sometimes cause parents to worry about vaccines. We found that some parents who did not speak English had not heard these stories and so did not have the worries that other parents might. Some parents had wanted information about vaccines to be given to them in the language they speak at home. Finally, vaccines go through many years of testing and are studied in groups of people from all different ethnic backgrounds. Some parents said that they wanted to know about this testing, so that they could be reassured that their children would react to the vaccines in the same way as other children.

We now have a better understanding of why some people do and do not get vaccines

This research has helped us to understand why children from some ethnic minority backgrounds might be more likely to get some vaccines. It also told us the type of information that parents from ethnic minority backgrounds want to know about vaccines to be confident that giving their child a vaccine is the right thing. In some situations it might be a good idea to tailor information about vaccines to parents from particular ethnic minority backgrounds to make sure they are getting all the information they want to have.

 

References

  1. Wagner KS, van Wijgerden JCJ, Andrews N, Goulden K, White JM: Childhood vaccination coverage by ethnicity within London between 2006/2007 and 2010/2011. Arch Dis Child 2014, 99(4):348-353. DOI: 10.1136/archdischild-2013-304388
  2. Mixer RE, Jamrozik K, Newsom D: Ethnicity as a correlate of the uptake of the first dose of mumps, measles and rubella vaccine. J Epidemiol Community Health 2007, 61(9):797-801. DOI: 10.1136/jech.2005.045633

Could a leaflet help catch cancer earlier?

By Jo Waller, on 4 May 2016

We’ve written here before about the difficulty of recognising symptoms that could be signs of cancer, and knowing when it’s appropriate to go to the doctor about them. There’s lots of evidence that cancer is more treatable if it’s found at an earlier stage, but we know less about effective ways of encouraging people to seek help appropriately.

Encouraging people to seek help

Our new study tried to do just this. We focused on gynaecological cancers – that is ovarian, cervical, endometrial (womb/uterine), vaginal and vulval cancers which together affect over 20,000 women a year in the UK. We know from previous research that some of the things that stop people going to the doctor with symptoms are:

1) Not knowing that the symptom could be a sign of something serious
2) Worry about wasting the doctor’s time
3) Embarrassment about discussing or exposing intimate parts of the body
4) Worry about what the doctor might find

So we designed an information leaflet that addressed some of these issues. It provided details about possible symptoms of gynaecological cancer and a checklist to help women record their symptoms and make a plan to visit their GP. It reassured women that their doctor would be happy to see them, and that the symptoms were unlikely to be serious. It addressed the issue of embarrassment and reminded women they could ask to see a female doctor.

 

In this study Leaflet 1, we uLeaflet 2sed questionnaires to measure the impact of the leaflet in the short-term. We asked 464 women about their symptom knowledge, the things that might put them off going to the doctor if they had gynaecological symptoms, and how quickly they thought they would seek help for a range of symptoms. We also asked about how anxious they were feeling right now, so we could see if the leaflet raised anxiety levels. Women then spent some time reading the leaflet before filling in another questionnaire.

What did we find?

After reading the leaflet, most women said they would seek help more quickly if they noticed one of the symptoms. In particular, we reduced the number of women who said they would never seek help for vague symptoms like bloating and feeling full quickly, which can be signs of ovarian cancer. Women reported fewer barriers to visiting their GP, and greater knowledge about possible symptoms of gynaecological cancer. There was no evidence that the leaflet made women feel anxious.

What next?

These findings are very encouraging, and suggest that a leaflet may be an effective way of promoting prompt help-seeking for these symptoms. But it’s also important to remember that it was an experimental study – women read the leaflet under controlled conditions, so it doesn’t tell us what impact the leaflet would have in a real-world setting where women might be sent it in the post, or handed it at their GP surgery. Under these circumstances, they might not even read it.

In addition, we could only measure women’s anticipated help-seeking, and we can’t be sure what they would really do if they had these symptoms. Even when people intend to seek help, life often gets in the way, other things take priority, and people don’t get round to making an appointment.

The next step will be to see what happens when we actually send the leaflet to women – will more of them seek help and, ultimately, will more cancers be diagnosed at an earlier stage when treatment is more effective? We hope to answer these questions in our future work.

Are self-reports of cancer screening participation accurate?

By Jo Waller, on 26 September 2015

By Siu Hing Lo

Health behaviour research often relies on surveys to collect data of people’s lifestyle and views about health. However, there is concern about the reliability of self-report measures. Common reasons for inaccurate self-report include the desire to give socially desirable answers and issues with recall. When people report their participation in cancer screening their answers are likely to be affected by both. Surveys consistently show that most people agree that screening is a good idea, so it is reasonable to assume they might be tempted to give a socially desirable answer when asked about their own behaviour.

Previous evidence from the United States suggests that social desirability is not the (main) explanation (Vernon et al., 2012). Nevertheless, recall could still be a significant issue. The most common screening tests used in the UK require participation at two- to five-yearly intervals. This means that accurate self-report requires people to recall what they have done over a long period of time. In our latest survey study, we asked respondents permission to check their NHS screening records, so we could compare their self-reported participation in bowel cancer screening with their NHS records.

Unfortunately only around 40% of the total survey sample agreed to this ‘record check’. People who agreed were also more likely to be more affluent and have participated in bowel cancer screening.
On the positive side, we showed that those who consented to the record check could accurately report whether they have ever take part in bowel cancer screening. A large majority also accurately reported whether they had taken part at least twice (81%) and whether they had taken part every time they had been invited (77%).

Interestingly, mismatches between self-report and records were due to both ‘over-reporting’ and ‘under-reporting’ of screening participation. On the one hand, one-fifth of respondents who said they had taken part every time, had in fact failed to respond to at least one invitation. On the other hand, roughly one-sixth reported having taken part once, even though – in reality – they had taken part at least twice.
Although we could only examine the accuracy of self-reported bowel cancer screening among survey respondents who gave permission for the record check, it allowed us to explore what type of biases are likely to result from different survey questions. The biggest obstacle to accurate self-report of bowel cancer screening seemed to be recall of the number of screening tests received and completed. Survey measures which rely less on recall of each screening episode are therefore more likely to yield reliable data.

References

Lo, S.H., Waller, J., Vrinten, C., Wardle, J. & C. von Wagner (2015), ‘Self-reported and objectively recorded colorectal cancer screening participation’, Journal of Medical Screening, in press.

Vernon S.W., Abotchie P.N., McQueen A., et al. (2012), ‘Is the Accuracy of Self-Reported Colorectal Cancer Screening Associated with Social Desirability?’, Cancer Epidemiology Biomarkers and Prevention, 21, 61-5.