Health behaviour mediates the relationship between Type D personality and subjective health in the general population

TL;DR: It is found that health behaviour partially mediates the relationship between Type D personality and subjective health and may partly explain the relationshipBetween Type D and poor health outcomes.

Abstract: Type D personality is associated with unhealthy behaviour and poor subjective health in the general population. This study investigated whether health behaviour mediates the relationship between Type D and subjective health. There were 217 participants who completed measures of Type D, health-related behaviour, physical symptoms and quality of life. Type D individuals reported significantly less healthy behaviour and significantly poorer subjective health than non-Type Ds. In addition, it was found that health behaviour partially mediates these relationships. The study demonstrates that health behaviour may partly explain the relationship between Type D and poor health outcomes.

Summary

Introduction

• Type D personality’s association with negative health outcomes has been well documented (e.g., Denollet et al., 1996; Denollet, Vaes & Brutsaert, 2000).
• Studies have shown that Type D is associated with a threefold increased risk of poor prognosis and morbidity in cardiac patients (Denollet, Schiffer & Spek, 2010).
• It has been suggested that Type D may promote the progression of heart disease indirectly through having an adverse effect on health behaviours (Kupper et al., 2013; Svansdottir et al., 2012).
• Specifically, Type D individuals were found to smoke more, exercise less, and eat a poorer diet than non-Type D’s.

Participants and procedure

• In a cross-sectional study, the sample comprised of 217 adults recruited via convenience sampling from the general population and from a University setting (76 males, 141 females, mean age: 31.9 years).
• Ethical approval was obtained from the institutional review board prior to testing.
• All participants were given a brief explanation of the study and provided with a questionnaire pack containing an information sheet, consent form, debrief sheet and a questionnaire consisting of demographic questions and measures of Type D personality, health behaviour, physical symptoms and quality of life.

Type D personality

• Type D personality was measured using the Type D Personality Scale (DS14; Denollet, 2005).
• This is a 14-item scale measuring the two components of Type D, Negative Affectivity (NA) and Social Inhibition (SI).
• NA (e.g., ‘I often feel unhappy’ and SI (e.g., I am a closed kind of agreement with each item on a five-point Likert-type scale ranging from true to false.
• Participants are classified as having a Type D personality if they score ≥10 on both the NA and SI subscales (Denollet, 2005).
• Cronbach’s α = .89 for NA and .88 for SI indicating high levels of internal consistency.

Health behaviour

• The health-related behaviours that participants performed was measured using the full version of The General Preventative Health Behaviours Checklist (Amir, 1987).
• The scale lists 33 behaviours (e.g., ‘eat sensibly’, ‘get enough sleep’, ‘get enough exercise’) and participants were required to state whether they do not, sometimes or always/almost always engage in each behaviour.
• A higher score indicated that the participant engages in more health beneficial behaviours.
• Cronbach’s α=.88 indicating good levels of internal consistency.

Physical symptoms

• The Cohen-Hoberman Inventory of Physical Symptoms (CHIPS: Cohen & Hoberman, 1983) consists of 33 items which assess the level at which the participant has experienced a selection of physical symptoms (e.g., sleep problems, headache, cold or cough) during the two weeks prior to the questionnaire being completed.
• Participants rated this on a Likert scale ranging from 0 (not been bothered by the problem) to 4 (the problem has been an extreme bother), with higher scores indicating higher levels of symptoms.
• The World Health Organisation Quality of Life Questionnaire (WHOQOL-BREF: The WHOQOL Group, 1996) is a 26-item measure used to investigate a participant’s perceived quality of life.
• A higher score indicates a better quality of life.
• Cronbach’s α= .82 indicating high internal consistency in the current study.

Statistical analysis

• T-tests were carried out to examine the differences between Type D and non-Type D individuals using the traditional categorical cut-off method of classifying Type D (Denollet, 2005) in relation to their health behaviours, quality of life, and physical symptoms.
• In addition, correlation analyses were performed in order to analyse the association between Type D (i.e., the multiplicative interaction term of NAxSI) and health behaviour and each of the subjective health outcomes.
• The correlations were carried out in line with suggestions from some authors that Type D may be better treated as a dimensional construct (Ferguson et al., 2009; Williams et al., 2011; Gilmour & Williams, 2012).
• Finally, in order to test the mediating effects of health behaviours on the relationship between Type D and subjective health the authors conducted mediation analysis using a regression-based approach and following the recommendations of Preacher and Hayes (2008), and Hayes (2013).
• Type D was the independent factor, physical symptoms and quality of life were the dependent factors, and health behaviour was entered as the mediator in the SPSS PROCESS tool created by by Preacher and Hayes (2008) the authors used a 95% confidence interval of the indirect effects with 1000 bootstrap resamples.

Mediation Analysis

• To determine if health behaviour mediates the effect of Type D on subjective health (physical symptoms and quality of life), mediation analyses were carried out.
• The first analysis used physical symptoms as the dependent variable.
• As a result of the above conditions being met, mediation analyses were conducted.
• Age and gender were entered as covariates in the mediation analysis.
• It was also shown that the direct effect of Type D on quality of life remained significant, when controlling for health behaviours, thus suggesting that health behaviours are a partial mediator of the relationship.

Discussion

• The present study has established that Type D individuals engage in fewer health beneficial behaviours than non-Type D individuals, and that these health behaviours partially mediate the relationship between Type D and subjective health outcomes (i.e., physical symptoms and quality of life).
• Health behaviours therefore represent one potential mechanism to explain the negative effect of Type D on health outcomes.
• If the mediating effect of health behaviours is also identified in the relationship between Type D and poor clinical outcome in cardiac populations this represents a potential avenue for intervention as Type D individuals may benefit from intensive exposure to behaviour-change techniques.
• Bunevicius A, Brozaitiene J, Staniute M, Gelziniene V, Duoneliene I, Pop VJ, Bunevicius R and Denollet J (2014).
• Lack of prognostic value of Type D personality for mortality in a large sample of heart failure patients.

Ferguson E, Williams L, O’Connor R, Howard S, Hughes BM, Johnston DW and O’Carroll RE

• (2009) A taxometric analysis of Type-D personality.
• Annals of Behavioral Medicine 43: 299-310. Hayes AF (2012) PROCESS: A versatile computational tool for observed variable mediation, moderation and conditional process modelling (white paper).
• Guildford Publications Karlsson MR, Edstrom-Pluss C, Held C, Henriksson P, Billing E and Wallen NK (2007) Effects of expanded cardiac rehabilitation on psychosocial status in coronary artery disease with focus on Type D characteristics, also known as New York.
• The WHOQOL Group (1996) WHOQOL: Introduction, administration, scoring and generic version of assessment.

Figures

Table 1: Key variables stratified by Type D.

Frequently asked questions

Q1. What have the authors contributed in "Health behaviour mediates the relationship between type d personality and subjective health in the general population abstract type d personality is associated with unhealthy behaviour and poor subjective health in the general population. the current study investigated whether health behaviour mediates the relationship between type d and subjective health. there were 217 participants who completed measures of type d, health-related behaviour, physical symptoms and quality of life. type d individuals" ?

The study demonstrates that health behaviour may partly explain the relationship between Type D and poor health outcomes. 

Q2. What future works have the authors mentioned in the paper "Health behaviour mediates the relationship between type d personality and subjective health in the general population abstract type d personality is associated with unhealthy behaviour and poor subjective health in the general population. the current study investigated whether health behaviour mediates the relationship between type d and subjective health. there were 217 participants who completed measures of type d, health-related behaviour, physical symptoms and quality of life. type d individuals" ?

First, as the sample consists of healthy participants future research is required in order to test the mediating effects of health behaviour on the relationship between Type D and adverse clinical outcome in cardiac patients. Health behaviours therefore represent one potential mechanism to explain the negative effect of Type D on health outcomes. If the mediating effect of health behaviours is also identified in the relationship between Type D and poor clinical outcome in cardiac populations this represents a potential avenue for intervention as Type D individuals may benefit from intensive exposure to behaviour-change techniques. 

Q3. What was the significance of Type D on health behaviours?

Regression analysis showed that Type D significantly predicted physical symptoms, (β = .291, t(216) = 4.39, p < .001), and health behaviours, (β = .337, t(216) = 5.19, p < .001). 

Q4. What was the effect size of type D on health behaviours?

Regression analyses showed that Type D significantly predicted quality of life, (β = .444, t(216) = 7.23, p < .001), and health behaviours, (β = .337, t(216) = 5.19, p < .001). 

Q5. What is the main reason for the link between Type D and poor lifestyle behaviours?

One other potential explanation for the link between Type D and poor lifestyle behaviours is that Type D individuals have less motivation for performing healthenhancing behaviours. 

Q6. What was the effect size of type D on quality of life?

Mediation analyses showed that health behaviours mediate the relationship between Type D and quality of life (β =2.60, CI = 1.49 to .4.3). 

Q7. What is the recent study to conclude that Type D has a negative impact on health?

A review by Mols and Denollet (2010) concluded that Type D has a negative impact on mental health status (e.g., symptoms of depression and anxiety) and on physical health status, including more somatic symptoms and lower health status. 

Q8. What is the type of personality that has been associated with adverse outcomes in cardiac patients?

from 12 independent studies, that Type D has an effect on prognosis in cardiac patients, with a mean odds ratio of 2.3 for adverse events. 

Q9. How many Type D participants were included in the sample?

From the sample of 217 participants, 69 (19 males and 50 females) were classified as Type D (31.8%) according to the recommended cut-off points of ≥10 for the subscales of NA (M = 16.00; SD = 4.82) and SI (M = 14.03; SD = 2.88). 

Q10. What was the significance of the correlations between Type D and physical symptoms?

Results of the analysis demonstrated the mediating effect of health behaviours in the relationship between Type D and physical symptoms (β =-2.42, CI = -4.3 to -1.01). 

Q11. What is the effect size of type D on physical symptoms?

In terms of effect size, kappa-squared = .048, CI = .01 to .11, demonstrating a relatively small effect size for the partial mediating effects of health behaviour on the Type D and physical symptoms relationship. 

Q12. What is the role of Type D personality in the development of cardiac disease?

It has been suggested that Type D may promote the progression of heart disease indirectly through having an adverse effect on health behaviours (Kupper et al., 2013; Svansdottir et al., 2012). 

Q13. What is the effect size of type D on health behaviour?

Kappa squared = 0.11, CI = .06 to .17, demonstrating a medium effect size for the partial mediating effect of health behaviour on the Type D and quality of life relationship. 

Q14. What is the relationship between Type D personality and health outcomes?

As well as being linked to a variety of physiological and immune system responses (e.g., Molloy et al., 2008; Whitehead et al., 2007), Type D has also been consistently linked to health behaviours (e.g., Williams et al., 2008). 

Q15. What is the significance of the correlation analysis?

In addition, correlation analyses were performed in order to analyse the association between Type D (i.e., the multiplicative interaction term of NAxSI) and health behaviour and each of the subjective health outcomes.