Friday November 4 2016
Health anxiety linked to heart disease risk
"Worried well 'make themselves sick'," reports The Daily Telegraph.
Several other news outlets covered the same story with headlines about how the "worried well" may be more likely to develop heart disease.
The stories are based on a Norwegian population study with 7,052 participants that aimed to see whether health anxiety (hypochondria) was linked with the development of heart disease.
Middle aged participants filled in questionnaires about their health concerns and their heart health was tracked over a 12 year period.
The study found people with health anxiety had a 73% increased chance of developing heart disease compared to those without.
However, it's difficult to say with certainty that health anxiety directly and independently increases the risk of heart disease.
The researchers took into account other heart disease risk factors, such as obesity, smoking, blood pressure, cholesterol and diabetes. But they didn't delve further into the people's health.
We can't exclude the possibility that other health factors may have contributed both to the people's health worries and their heart disease risk.
Nevertheless, the study highlights that anxiety, like other mental health problems, can affect your health in many ways.
If you are struggling with feelings of anxiety and it's affecting your daily life, contact your GP to get help and support. There are many treatments that work well for anxiety.
Find out more about anxiety and accessing therapy and counselling.
Where did the story come from?
The study was carried out by researchers from University of Bergen, Sandviken University Hospital, Haraldsplass Deaconal University Hospital, and the Norwegian Institute of Public Health.
The study received no additional sources of funding.
It was published in the peer reviewed British Medical Journal and is open-access, so it's free to read online.
Most of the media coverage takes the same slant that "the worried well" have a greater risk of heart disease.
However, care should be taken in calling people the "worried well" or "hypchondriacs". As the researchers themselves openly acknowledge, their study was not able to tell whether people may have had an underlying health problem causing their concerns.
What kind of research was this?
This was a prospective cohort study that followed people over time to investigate whether health anxiety may be linked with the development of heart disease.
Lifestyle risk factors, such as smoking, obesity and high cholesterol, are known to be linked with heart disease risk.
Previous studies have also suggested anxiety is an independent risk factor for heart disease.
The researchers therefore also wanted to see whether any link between anxiety and heart disease in their study was influenced by other established risk factors.
A prospective cohort study is the best way of looking at whether a particular factor or exposure is linked with a longer term health outcome.
But it can still be difficult to fully account for all variables that may be involved, particularly with subjective factors such as worry or anxiety.
What did the research involve?
The Hordaland Health Study (HUSK) invited all people living in the Hordaland region of Norway and born between 1953-58 to complete a health questionnaire in 1997.
They also had a physical examination when height, weight, blood pressure and blood samples were taken.
Anxiety was assessed by a widely-used self-report scale, the Whitley Index. This has 14 questions (each scored 1 to 5) covering things such as fears and concerns about having an illness.
For the purpose of this study, being above the 90th percentile, or a score of 31 or more, was considered the cut-off for having health anxiety.
Participants were followed for up to 12 years to 2009 to look for the development of heart disease.
To identify cases, researchers linked the cohort participants with the Cardiovascular Diseases in Norway (CVDNOR) study which collected data on all hospitalisations and deaths due to cardiovascular disease in Norway from 1994 to 2009.
The researchers adjusted their analysis for several confounding factors assessed in the questionnaires and examinations.
This included gender, age, marital status, educational level, alcohol, physical activity, BMI, smoking, cholesterol, blood pressure and diabetes.
They excluded people who had had heart disease before enrolling in the study, or developed it within the first follow-up year in case it was already present.
This left a final sample of 7,052 people who had completed enrolment assessments and had answered the Whitley Index. Their average age was 43 years.
What were the basic results?
Of the sample, 10% (710 people) met the criteria for having health anxiety.
On average, after seven years of follow-up, 3.3% of all participants (234) developed heart disease. But the rate was higher among those with health anxiety – 6% compared to 3% for all participants.
Various other health and lifestyle factors were associated with health anxiety, including age, gender, educational level, smoking, alcohol, physical activity and BMI.
In analyses adjusted for all confounding factors, people with health anxiety still had a 73% increased risk of developing heart disease (hazard ratio [HR] 1.73, 95% confidence interval [CI] 1.21 to 2.48).
When the researchers analysed separately by gender though, anxiety was still significantly linked with heart disease development in men (HR 1.78, 95% CI 1.17 to 2.71) but not in women (HR 1.58, 95% CI 0.78 to 3.20).
Further analysis revealed a "dose-response" pattern where increasing scores on the Whitley Index were more strongly linked with the risk of heart disease.
How did the researchers interpret the results?
The researchers conclude: "This finding corroborates and extends the understanding of anxiety in various forms as a risk factor for [heart disease]. New evidence of negative consequences over time underlines the importance of proper diagnosis and treatment for health anxiety".
This study is a valuable contribution to research investigating whether health anxiety may be linked with the development of heart disease.
The study has several strengths, including:
- the large community-based population sample
- long follow-up time
- use of a well-developed tool to assess health anxiety
- heart disease diagnosis based on hospital medical records through the CVDNOR study, which is considered to have good quality data
- careful analysis and adjustment for other known health and lifestyle risk factors for heart disease that may be influencing the link
However, it is difficult to conclude with certainty that health anxiety directly and independently increases the risk of developing heart disease, and to attach a definite figure to this risk.
The study excluded people who already had a diagnosis of heart disease at the start of the study, or were hospitalised for heart disease within the first year of follow-up.
This is to try and rule out the possibility of reverse causation. In other words, that the person had heart disease to start with and it's their health problems that were causing their anxiety, rather than anxiety causing the health problem.
Nevertheless, as the researchers acknowledge, the Whitley Index "does not discern between 'imagined' illness or more legitimate reasons for concern".
The study analysed several known health risk factors for heart disease such as diabetes, blood pressure and cholesterol, and adjusted for these, but didn't explore what else might be affecting the person's health.
The person may have had other physical or mental health illnesses that were contributing to their anxiety and that may have also been contributing to their risk of heart disease – for example, cancers, respiratory or musculoskeletal illnesses.
Even with the best attempts to adjust for confounding factors, it's still difficult to say these people were just the "worried well" and weren't concerned for their health for good reason.
Other points to note include the relatively low participation rate of 63% of all those eligible to take part in the study. It is possible that health and anxiety levels may have differed between those who did and did not take part.
There may also be differences in lifestyle and environment between Norway and the UK or other countries, which may make the results less applicable elsewhere.
Despite the limitations of this study, the fact remains that anxiety, like other mental health problems, can affect your health in many ways.
If you are struggling with feelings of anxiety and it's affecting your daily life, contact your GP to get help and support. In some areas, you can also self-refer for therapy.
Find out more about anxiety and accessing therapy and counselling.