‘Health Chatter’: Research Department of Behavioural Science and Health Blog
  • Pages

  • Our Twitter Feed

  • A A A

    Why do some parents choose not to vaccinate against HPV?

    By Lauren Rockliffe, 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.

     

    Perceived weight discrimination linked to physical inactivity

    By Sarah Jackson, on 8 March 2017

    Rises in obesity prevalence over recent decades have corresponded with increasing stigmatisation of, and discrimination against, individuals living with obesity. Weight stigma is often justified on the basis that it might encourage people to lose weight, but a growing evidence base indicates that experiences of weight-related stigmatisation may in fact encourage behaviours that promote obesity.

    A few small studies have indicated that people who face weight stigma are more inclined to avoid physical activity, but none have been able to clearly establish what effect experiencing stigma has on actual exercise behaviour.

    In a new study published today in BMJ Open we explored the relationship between weight discrimination and physical activity. The research involved 5,480 men and women aged 50 years and older taking part in the English Longitudinal Study of Ageing, a large population-based cohort of middle-aged and older adults living in England.

    Overall, one in twenty people said they had been discriminated against because of their weight, ranging from lack of respect or courtesy to being threatened or harassed. Rates of weight discrimination varied considerably according to how overweight a person was, from 0.9% of people with a body mass index (BMI) in the overweight range (25-29.9) to 13.4% of people with obesity (BMI greater than 30).

    Importantly, we found that people who had experienced weight-related discrimination had almost 60% higher odds of being inactive and 30% lower odds of engaging in moderate or vigorous exercise once a week than their peers.

    Interestingly, a person’s BMI in itself did not affect the relationship between weight discrimination and exercise, indicating that people who experience weight-related discrimination are likely to be less physically active, regardless of their weight.

    There could be several reasons for our findings. People who feel stigmatised may be more self-conscious about exercising in front of others for fear they will attract undesirable attention, leading to embarrassment or teasing. They may also begin to believe the negative stereotypes against themselves as lazy and worthless, leaving them wondering why they should bother trying to be active.

    Given the substantial benefits of being physically active for both physical and mental health, interventions that aim to reduce weight bias at a population level – for example through schools, local communities or national campaigns – may have greater impact on health than those that encourage people to lose weight. A Health at Every Size approach may be helpful in encouraging people to develop and maintain healthy habits, including regular physical activity, for the sake of health and wellbeing as opposed to weight control.

     

    Article link:
    Jackson SE, Steptoe A. Association between perceived weight discrimination and physical activity: a population-based study in English middle-aged and older adults. BMJ Open. 2017;7:e014592.
    http://bmjopen.bmj.com/content/7/3/e014592.info

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

    By Lauren Rockliffe, 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!

     

     


     

    Congratulations to Dr Jo Waller

    By Alice Forster, on 7 November 2016

    Alice Forster and Laura Marlow

    Today at the NCRI Cancer Conference in Liverpool, the inaugural Jane Wardle prize was awarded to our very own Dr Jo Waller to recognise her world-leading contribution in cervical cancer prevention. The prize was set up by Cancer Research UK in memory of Professor Jane Wardle who died last year. Jo has been at the Health Behaviour Research Centre for 15 years and was herself mentored by Jane Wardle. In this blog we highlight some of Jo’s key research in cervical cancer prevention during this time.

     

    In 2005, Jo completed a PhD exploring psychosocial issues surrounding the viral aetiology of cervical cancer. These early studies explored the emotional and social consequences of a HPV diagnosis and how women make sense of a HPV positive result at cervical screening. The findings highlighted extremely low awareness of HPV and poor understanding about how cervical cancer develops. This work also showed the importance of providing good information to ensure minimal anxiety when receiving a HPV positive result at screening and to avoid stigmatising cervical cancer.

     

    Jo and her colleagues went on to explore psychosocial issues surrounding HPV vaccination before and after its introduction in 2008. This research helped identify the most appropriate age for the vaccine and contributed to the content of the information materials provided. In addition, this work offered reassurance that vaccination against a sexually transmitted infection (the HPV vaccine) did not result in changes to girls’ sexual behaviour as some media reports had suggested. Jo’s work has also explored why certain sub-groups of the population, such as young women and ethnic minority women are less likely to participate in cervical screening.

     

    In 2014, Jo was awarded a prestigious Cancer Research UK Career Development Fellowship to continue her research in cervical cancer prevention. Jo now formally manages a team of researchers and her current research activities include understanding non-participation in cervical cancer screening and HPV vaccination, developing interventions to improve uptake of these cervical cancer control interventions, and evaluating the psychological impact of primary HPV testing within cervical screening.

     

    Jo has also been involved in numerous other bodies of work over the last 10 years including development of the Cancer Awareness Measure and studies exploring informed choice about screening. She is also an informal mentor to many students and colleagues. We are all very proud of Jo’s achievement today. Well done Jo!

     

    You can read more about our current work in cervical cancer prevention on our website.

    Weight discrimination is chronically stressful

    By Sarah Jackson, on 18 October 2016

    Stigmatisation of obesity remains one of “the last acceptable forms of prejudice”.  People with obesity are widely stereotyped as lazy, weak willed and personally to blame for their weight by the media, employers, educators, health care professionals, and even their friends and family.

    Facing discrimination can understandably be very stressful in the moment.  Small experiments have shown that asking people to watch a video that stigmatises obesity, or telling them that their body size and shape are unsuitable to take part in a group activity, increases levels of the stress hormone cortisol in their saliva.

    But what wasn’t known until now was whether discrimination has lasting effects on stress levels.  This is important because acute (short-term) stress is a protective, adaptive response whereas chronic stress can have a damaging effect on the body.

    In a new study published last week in Obesity we explored the relationship between weight discrimination and chronic stress.  The research involved 563 men and women with obesity (body mass index ≥30) aged 50 years and older taking part in the English Longitudinal Study of Ageing (ELSA), a large population-based cohort of middle-aged and older adults living in England.

    Rather than measuring levels of cortisol in saliva, which are sensitive to daily fluctuations and short-term factors such as diet, we analysed cortisol levels in hair.  Measuring hair cortisol is a new technique that gives an indication of average levels of cortisol in the body over several months.  Hair grows at approximately 1 cm per month, so the 1 cm of hair nearest to the scalp represents average exposure to cortisol over the last month.

    We found that one in eight people with obesity had experienced discrimination because of their weight, ranging from lack of respect or courtesy to being threatened or harassed.  Among people with severe obesity (BMI ≥40), one in three reported discrimination.

    Importantly, our findings revealed that average levels of cortisol in hair were 33% higher in individuals who had experienced weight discrimination than those who had not.  People who experienced more frequent weight discrimination had higher hair cortisol levels than those who faced less regular discrimination.

    The results of this study provide evidence that weight discrimination is associated with the experience of stress at a biological level.  Because experiencing high levels of cortisol over a prolonged period can have a substantial impact on health and wellbeing, it is likely that weight discrimination contributes to many of the negative psychological and biological consequences of obesity.  In addition, cortisol is known to increase appetite and fat storage, making people who experience weight discrimination more likely to gain weight.

     

    Article link:

    Jackson SE, Kirschbaum C, Steptoe A. Perceived weight discrimination and chronic biochemical stress: A population-based study using cortisol in scalp hair. Obesity. First published ahead of print 14 October 2016. doi:10.1002/oby.21657

    http://onlinelibrary.wiley.com/doi/10.1002/oby.21657/full

    Toddlers’ food fussiness is heavily influenced by genes

    By Andrea D Smith, on 14 October 2016

    Written by Andrea Smith, Alison Fildes and Clare Llewellyn

    In early childhood, children are gradually introduced to an increasingly varied diet. While some children happily accept new foods and enjoy eating lots of different kinds of foods, many are hesitant. Food avoidant behaviour can be broadly classified into two traits: ‘Food Fussiness’ and ‘Food Neophobia’. Food Fussiness is the tendency to be highly selective about the textures, taste and smell of foods you are willing to eat and is often seen as a consequence of inadequate parenting. However, Food Neophobia – the refusal to try new foods – is often seen as a normal development stage experienced by most young children regardless of the way their parents feed them. Fussy and neophobic eating behaviours typically emerge in toddlerhood and commonly peak between two and six years of age; but for some children these traits persist into later childhood.

    Food avoidant behaviour can be both frustrating and worrying for parents; children who eat only a restricted range of foods might miss out on key dietary nutrients essential for healthy development. In particular, fussy eaters tend to reject nutrient-dense foods such as vegetables. Early childhood is also an important period during which food preferences develop; learning to like a range of healthy foods requires the child to try a wide variety of different foods. Researchers have therefore been interested in finding out what shapes food avoidant behaviour in early life. Some research has suggested that children who are breastfed for longer and whose parents use less persuasive feeding practices (e.g. rewarding with food) are less likely to display fussy eating behaviours; suggesting that there are important environmental shapers of this behaviour. On the other hand, Food Neophobia is associated with temperamental traits such as shyness or inhibition; these characteristics have an established genetic influence, indicating that neophobia might also have a strong genetic basis.

    In a new study published in the Journal of Child Psychology and Psychiatry we used data from the Gemini twin cohort to investigate the extent to which genes and environmental factors influence children’s food fussiness and food neophobia. Gemini is a large study of 2400 pairs of twins that was set up in 2007 to explore early life growth and behaviour. Twin studies are useful for investigating the relative importance of genetic- and environmental factors on individual differences in traits such as food avoidant behaviours. The current study was based on data from 1,932 families collected when the twins where 16 months old.

    We found that both food fussiness and food neophobia have a strong genetic basis, with 46% and 58% of the variation in each trait explained by genetic influences respectively. The shared home environment (which includes factors such as parental feeding practices) was a more important influence on Food Fussiness than Food Neophobia; but overall, these environmental factors were less important than a child’s genetic predisposition towards these behaviours.

    The finding that there is substantial genetic influence on fussy eating behaviour in early childhood might be quite a relief for some parents who can often feel judged or guilty about their children’s fussy eating. Understanding that these traits are largely innate might help to deflect this blame.

    However, our genes are not our destiny. Establishing the importance of genetic influences on fussy eating behaviours in early childhood does not imply that these behaviours cannot be changed. An effective intervention to overcome food rejection is through repeated exposure to the problem food; the more a child tries a food, the more familiar it becomes and the more they learn to like it. In our group we have developed a tasting game called ‘Tiny Tastes’ to help families introduce foods to reluctant and fussy eaters. This is an avenue through which parents might be able to positively change fussy or neophobic eating behaviours.

    _______________________________________________________________________

    Food fussiness and food neophobia share a common etiology in early childhood

    Andrea D. Smith, Moritz Herle, Alison Fildes, Lucy Cooke, Silje Steinsbekk, and Clare H. Llewellyn

    Article link: http://onlinelibrary.wiley.com/doi/10.1111/jcpp.12647/epdf

    Fifty shades of cancer fear

    By Charlotte Vrinten, on 7 October 2016

    Are you afraid of cancer? Don’t worry, you’re in good company. Surveys show that many people in the UK are afraid of cancer [1]: 35% of people fear cancer more than other serious illnesses such as heart disease or HIV [2], and 20% fear cancer more than being in debt, being in a car accident, or losing a job. [3] But although we know that lots of people find cancer frightening, we don’t really know what it is about cancer that they are afraid of. So in our latest study, we aimed to explore just that.

    You may wonder why it is important to pinpoint what it is about cancer that worries people. The answer is that the nature of the fear may determine how people behave when it comes to cancer screening or responding to suspicious symptoms. For example, a study in the US found that worry about prostate cancer motivated men to have a prostate examination, while fear of the examination put them off. Intuitively, we know that there are many different aspects to cancer that could be frightening, but until now, no one had really explored this.

    In our study, which was published today, we collated findings from 102 interview studies from 26 countries to see what people in the general population(as opposed to cancer patients) said they feared about cancer [5]. All the studies combined included more than 3,500 participants.

    We found that those who are afraid of cancer seemed to view cancer as an indestructible enemy that randomly sneaks up on people to kill them – reprising the media’s ‘war on cancer’ theme. This rogue super soldier inspired lots of fear, which could be increased or decreased by factors such as family history of cancer, symptoms, or experiences of cancer in others, as well as coping styles such as ‘checking up on the enemy’ through cancer screening, or pretending that it doesn’t exist.

    In addition, we found that there are also specific aspects of cancer that inspire fear. Many participants were fearful of the emotional upset that a cancer diagnosis would cause. Fears of cancer treatment, such as chemotherapy and surgery, were also mentioned in many studies, in addition to the fear that surgery might cause cancer to spread (a fear that is completely unfounded). Some women expressed fears about losing intimate body parts and thereby their gender identity, for example if a breast needed to be removed to treat breast cancer.

    The social implications of being a cancer patient also inspired a lot of fear. Some people feared that a cancer diagnosis would stigmatise them, or would attract blame. Many people also worried that a cancer diagnosis would have a negative effect on their family, by burdening them financially, physically, or psychologically. Some women were worried that losing a breast would mean that their partners would no longer find them attractive and might abandon them.

    Finally, we found many references to fears about dying from cancer. Some said that they were so afraid of dying from cancer that they’d rather die without knowing that they had it.

    What can we conclude from these findings? We have shown for the first time that there are many different things that people in the general population – without a cancer diagnosis – worry about when it comes to cancer. What we do not yet know is how common these worries are, and how they may influence willingness to take steps to reduce cancer risk or get it detected early. These are questions that we will be investigating further. For example, we recently completed a national survey to find out how common various cancer worries are, the results of which will be presented at the upcoming NCRI conference. Watch this space!

    References

    [1] Vrinten C, van Jaarsveld CHM, Waller J, von Wagner C, Wardle J. (2014). The structure and demographic correlates of cancer fear. BMC Cancer, 14(1), 597.

    [2] http://www.cancerresearchuk.org/about-us/cancer-news/press-release/2011-08-15-people-fear-cancer-more-than-other-serious-illness

    [3] http://www.cancerresearchuk.org/about-us/cancer-news/press-release/2010-12-08-cancer-is-biggest-fear-but-34-per-cent-put-it-down-to-fate

    [4] Consedine NS, Adjei BA, Ramirez PM, McKiernan JM. (2008). An object lesson: source determines the relations that trait anxiety, prostate cancer worry, and screening fear hold with prostate screening frequency. Cancer Epidemiology Biomarkers & Prevention, 17(7), 1631-1639.

    [5] Vrinten C, McGregor LM, Heinrich M, von Wagner C, Waller J, Wardle J, Black GB. (2016). What do people fear about cancer? A systematic review and meta-synthesis of cancer fears in the general population.  Psychooncology, Epub 6 Oct 2016.