Type D personality and physical inactivity: The mediating effects of low self-efficacy

Abstract

Type D personality is associated with health-damaging behaviours among the general population. This study assessed the relationship between Type D personality, physical activity and self-efficacy. A total of 189 participants completed measures of Type D personality, physical activity and self-efficacy. Type D individuals had significantly lower levels of self-efficacy and engaged in significantly less walking and total exercise compared to non-Type D’s. Furthermore, self-efficacy fully mediated the relationship between Type D and physical activity. Low levels of self-efficacy may be one mechanism to help explain why Type D individuals engage in more disease-promoting behaviours.

Keywords

health behaviour physical activity self-efficacy Type D personality

Introduction

Type D personality is the combination of two traits: negative affect (NA) and social inhibition (SI) (Denollet et al., 2000). Individuals considered to be Type D consistently experience negative emotions and abstain from sharing these emotions with others due to anxieties concerning their potential response and fears over how they will be perceived (Denollet, 2005). Denollet (2005) emphasises that it is the combination of high scores on each of these two stable personality traits that constitutes as the Type D construct. Traditionally, Type D personality was categorised in individuals who scored ⩾10 on both the NA and SI subscales of the Type D Scale. Recently, Denollet et al. (2013) have demonstrated the robustness of the standard, dichotomised measure of Type D as an independent predictor of adverse cardiovascular events in patients with coronary artery disease. However, Ferguson et al. (2009) have also proposed that Type D can be represented as a continuous construct (using the NA × SI multiplicative interaction term).

Since 1996, studies have indicated that Type D is a risk factor for adverse health outcomes in cardiac patients (Denollet et al., 2006, 2010, 2013). Denollet et al. (1996) reported that Type D coronary heart disease (CHD) patients have a fourfold mortality risk compared to non-Type D CHD patients. Schiffer et al. (2010) reported similar findings among chronic heart failure patients while controlling for severity of disease. More recently, a meta-analysis found that Type D cardiovascular disease (CVD) patients were three times more at risk of a subsequent cardiac event or cardiac mortality than non-Type D CVD patients (O’Dell et al., 2011). Importantly, it has been established that Type D is a significant predictor of poor health outcomes in cardiac patients, independent of traditional biomedical risk factors including disease severity and diabetes (Martens et al., 2010). It has also been demonstrated that Type D is distinct from depression, with Type D representing a more chronic and covert form of distress (Denollet et al., 2009).

Other studies have assessed the effects of Type D personality in healthy populations and found it to be a significant predictor of physical and mental well-being (Mols and Denollet, 2010). De Fruyt and Denollet (2002) found that healthy Type D individuals reported significantly higher levels of anxiety and depression, as well as greater somatic complaints and difficulties sleeping. Similar findings were observed in a systematic review carried out by Mols and Denollet (2010) who reported that Type D is associated with greater symptoms of post-traumatic stress disorder, mental distress and reduced social support, as well as lower health status and increased reporting of flu-like symptoms among the general population.

A plausible way in which Type D may predict negative health outcomes is through its established relations with health behaviour (Williams et al., 2015). For example, compared to non-Type D individuals, Type D’s are less likely to adhere to medication (Wu and Moser, 2013; Wu et al., 2015) and to report their symptoms to healthcare professionals (Pelle et al., 2010). Furthermore, Type D individuals have been shown to engage in significantly less positive health behaviours (Williams et al., 2015), consume more alcohol (Bruce et al., 2013), spend less time outdoors (Williams et al., 2008), smoke more cigarettes (Ginting et al., 2014) and have poorer diets (Booth and Williams, 2015) than their non-Type D counterparts.

To date, limited research has investigated the link between Type D and physical activity. Those studies that have been conducted have shown that Type D individuals are significantly less active than non-Type D’s (Einvik et al., 2011; Gilmour and Williams, 2011; Kupper et al., 2013; Svansdottir et al., 2013). However, these studies have used brief measures of physical activity. A study conducted by Borkoles et al. (2010) sought to assess the prevalence of Type D in British males who were categorised as weight lifters, active or sedentary. The results demonstrated that Type D individuals are more likely to be sedentary and participate in less regular exercise than non-Type D’s. In another study of Dutch individuals, Type D personality was found to be linked to an unhealthy lifestyle, including not meeting the recommended Dutch standards for physical activity (Mommersteeg et al., 2010). In addition, a recent study undertaken by Bunevicius et al. (2014) demonstrated that Type D was independently associated with decreased exercise capacity and decreased motivation for physical activity in cardiac patients. However, other research has found no significant differences between Type D and non-Type D’s on exercise behaviour (Svansdottir et al., 2012; Williams et al., 2008). Both of these studies, however, simply asked whether participants engage in sufficient exercise, as opposed to enquiring in more depth about the actual exercise behaviours carried out. It is therefore apparent that research on the association between Type D and physical activity would benefit from a more comprehensive assessment of exercise behaviour. Therefore, this study seeks to examine the types of exercise that Type D and non-Type D individuals engage in while going about their daily lives, as well as assessing the frequency and duration of such activities.

One potential mechanism that could help explain why Type D’s differ from non-Type D’s with regard to health-related behaviours, including exercise, is the concept of self-efficacy. Central to Bandura’s social cognitive theory, self-efficacy is defined as an individual’s confidence in their ability to successfully carry out a particular behaviour associated with a desired outcome (Bandura, 1997). According to Hagger and Chatzisarantis (2005), an individual with high perceived self-efficacy towards a specific task will immerse themselves more deeply into the task at hand and are more committed to achieving the desired outcome. Furthermore, they consider challenges as tasks to be mastered and persist even in the face of difficulty. In contrast, a person with low perceived self-efficacy towards a particular task will anticipate that such challenges are beyond their capabilities and will generally avoid these situations and dwell on past failings (Lenz and Shortridge-Baggett, 2002).

To date, only two studies have explored the relationship between Type D and self-efficacy (Molloy et al., 2012; Wu et al., 2015). Molloy et al. (2012) showed that the NA component of Type D was a significant predictor of medication adherence following acute coronary syndrome and that lower levels of self-efficacy partly mediated the relationship between high levels of NA and poor medication adherence. More recently, Wu et al. (2015) reported that Type D heart failure patients were more likely to have lower self-efficacy and that low self-efficacy mediated the relationship between Type D and medication non-adherence. Therefore, this study will assess whether Type D individuals have lower levels of self-efficacy and whether this can explain why Type D individuals engage in more disease-promoting behaviours.

This study seeks to further investigate the relationship between Type D and exercise behaviour using a more comprehensive assessment of physical activity than has been used in previous studies. As far as we are aware, no past research has looked exclusively at Type D personality in relation to physical activity. Instead, previous studies have encompassed these behaviours with a variety of other health-related behaviours utilising brief measures (e.g. Ginting et al., 2014; Williams et al., 2008) or have concentrated solely on other health behaviours including alcohol consumption and medication adherence (Bruce et al., 2013; Williams et al., 2011). In addition to this, there is a lack of research investigating whether there is a relationship between Type D personality and self-efficacy. To date, only two studies have assessed this and found that lower levels of self-efficacy mediate the relationship between Type D and medication adherence (Molloy et al., 2012). Finally, much prior research on the relationship between Type D personality and health behaviours measured Type D using the traditional categorical cut-off points as recommended by Denollet (2005). As mentioned previously, Ferguson et al. (2009) have suggested that Type D may also be represented as a continuous construct using the NA × SI multiplicative interaction term. Both methods of scoring will therefore be utilised in this study.

Accordingly, this study has three main aims: (1) to investigate the relationship between Type D and physical activity, (2) to investigate the relationship between Type D and self-efficacy and (3) to determine whether self-efficacy mediates any relationship between Type D and physical activity.

Methods

Participants and procedure

The study comprised 189 participants (136 females and 48 males (5 missing); mean age = 24.8 years; standard deviation (SD) = 9.6; age range = 18–67 years). Participants were recruited via convenience sampling from the general population and from a university setting. All participants were provided with information as to what the study would entail before being invited to participate. Willing participants were then provided with a participant information sheet, a consent form, the Type D Scale (DS14; Denollet, 2005), the General Self-efficacy Scale (Schwarzer and Jerusalem, 1995), The International Physical Activity Questionnaire (IPAQ) and, finally, a debriefing sheet. Prior to testing, the study was approved by the institution’s psychology ethics committee.

Measures

Sociodemographic variables including age and gender were collected. In addition, participants were asked to complete the following measures via a paper-based questionnaire:

Type D personality

Type D personality was assessed by utilising the Type D Scale (DS14; Denollet, 2005). The scale consists of 14 items comprising two subscales. A 7-item subscale measures negative affectivity (e.g. ‘I often feel unhappy’) and a 7-item subscale measures SI (e.g. ‘I often feel inhibited in social interactions’). Participants rate their personality on a 5-point Likert-type scale that ranges from 0 = false to 4 = true. According to Denollet (2005), participants who score ⩾10 on both NA and SI are classified as having a Type D personality. We also examined Type D as a continuous measure using the NA × SI interaction term (Ferguson et al., 2009). Cronbach’s α = 0.89 and 0.83 for the NA and SI subscales, respectively, thus demonstrating high levels of internal consistency in the present sample.

Self-efficacy

Perceived self-efficacy was assessed by utilising the General Self-Efficacy Scale (Schwarzer and Jerusalem, 1995). The questionnaire consists of 10 items which refer to successful coping (e.g. ‘when I am confronted with a problem, I can usually find several solutions’). Responses are indicated on a 4-point Likert-type scale that ranges from 1 = not at all true to 4 = exactly true. This therefore yields a total score ranging from 10 to 40. Cronbach’s α = 0.75 indicates good internal consistency in the present sample.

Exercise behaviour

Exercise was assessed using the IPAQ which is available in both short form and long form. The long version was utilised in this study and consists of 27 items. Using the IPAQ, four domains of exercise were assessed: job-related, transportation, house and garden maintenance and leisure time. Furthermore, the questionnaire asks about the time spent sitting on both weekdays and weekend to measure weekly sedentary behaviour. For each of the four domains of exercise, the frequency (number of days per week) and the duration (number of minutes spent per day) doing both vigorous intensity and moderate intensity activities are documented. The amount of time spent walking is also recorded in the job, transportation and leisure time sections of the questionnaire. The volume of activity is calculated by weighing each type of exercise by metabolic equivalent of task (MET) to formulate a score in MET minutes. MET minutes are computed by multiplying the provided MET score of an activity by the number of minutes performed. By multiplying this again by the number of days per week that the activity is carried out, a MET minutes per week score can be formulated for each participant for vigorous, moderate and walking exercise. A total exercise MET score can then be calculated for each participant by combining their vigorous, moderate and walking MET minutes per week scores. Studies have demonstrated that the IPAQ instruments have acceptable reliability and validity across a diverse range of populations and settings (e.g. Craig et al., 2003).

Statistical analysis

T tests were carried out using the traditional categorical Type D cut-off points as recommended by Denollet (2005) to assess whether Type D and non-Type D individuals differ in exercise behaviour (vigorous, moderate and walking MET score, sitting and total MET score) and in perceived self-efficacy. Correlation analyses were then carried out to assess the association between the multiplicative interaction term of NA × SI, along with NA and SI as separate components for the previously mentioned exercise behaviours and perceived self-efficacy. Next, hierarchical multiple regression was performed to assess whether the categorical form of Type D predicts walking MET score and total MET score when controlling for age and gender. Finally, to test for the mediating effects of perceived self-efficacy on the Type D and exercise behaviour relationship, formal mediation analyses were performed using a regression-based approach and following the recommendations of Preacher and Hayes (2008) and Hayes (2013). Type D was the independent factor, physical activity was the dependent factor and self-efficacy was entered as the mediator in the SPSS PROCESS tool created by Preacher and Hayes for bootstrap analyses (Hayes, 2013). Following the procedures outlined by Preacher and Hayes (2008), we used a 95 per cent confidence interval (CI) of the indirect effects with 1000 bootstrap resamples.

Results

Prevalence of Type D personality

From the sample of 189 participants, 75 were classified as having a Type D personality (39.7%) using the recommended cut-off point of ⩾10 on both NA (M = 11.9, SD = 6.21) and SI (M = 11.03, SD = 5.7) subscales (Denollet, 2005).

The relationship between Type D personality, exercise behaviour and perceived self-efficacy (categorical analysis)

Using the traditional Type D cut-off points, results of a series of independent samples t tests demonstrated that Type D individuals (M = 1916.2, SD = 2027.6) scored significantly lower than non-Type D individuals (M = 3057, SD = 3269.7) on walking MET score (t(187) = 2.7, p < 0.01), suggesting that Type D individuals reported significantly lower levels of walking than non-Type D individuals. Furthermore, Type D individuals (M = 6133.2, SD = 6287) scored significantly lower in total exercise MET score than non-Type D individuals (M = 8435.7, SD = 8835.1), signifying that Type D individuals reported significantly less exercise than non-Type D individuals (t(187) = 1.95, p < 0.05). Finally, Type D individuals (M = 27.8, SD = 4.8) scored significantly lower on perceived self-efficacy than non-Type D individuals (M = 30.9, SD = 3.8), indicating that Type D individuals have significantly lower levels of self-efficacy compared to non-Type D individuals (t(187) = 4.8, p < 0.001). No significant differences were found between Type D and non-Type D individuals for vigorous or moderate physical activity or sitting behaviour.

Correlation analysis

In order to assess the relationship between the NA × SI interaction term and the outcome variables, a correlation analysis was conducted (see Table 1). Correlation analyses revealed that Type D (NA × SI) is significantly and negatively correlated with walking, r = −0.15, p < 0.05, and self-efficacy, r = −0.41, p < 0.001. These results indicate that higher scores on Type D are associated with lower levels of walking and self-efficacy. Further correlation analyses were conducted to examine the association between the individual components of Type D (NA and SI) and the outcome variables. The results showed a significant negative relationship between NA and self-efficacy (r = −0.43, p < 0.001), suggesting that higher levels of NA are associated with lower levels of self-efficacy. In addition to this, SI was significantly and negatively correlated with walking, r = −0.15, p < 0.05, total exercise, r = −0.18, p < 0.05, and self-efficacy, r = −0.28, p < 0.001. These results suggest that higher scores on SI are associated with lower levels of walking, total exercise and perceived self-efficacy.

Table 1.

Correlations of variables.

Variable	1	2	3	4	5	6	7	8	9
1. NA × SI	–	0.83**	0.81**	−0.11	−0.09	−0.15*	−0.14	0.10	−0.41**
2. NA		–	0.00**	−0.09	−0.08	−0.11	−0.12	0.04	−0.43**
3. SI			–	−0.14	−0.13	−0.15*	−0.18*	0.10	−0.28**
4. Vig MET				–	0.41**	0.46**	0.85**	−0.19**	0.09
5. Mod MET					–	0.31**	0.73**	−0.10	0.15*
6. Walk MET						–	0.73**	−0.08	0.21**
7. Total MET							–	−0.17*	0.18*
8. Sitting								–	−0.10
9. Self-efficacy									–

NA: negative affect; SI: social inhibition; Vig MET: vigorous exercise metabolic equivalent of task score; Mod MET: moderate exercise metabolic equivalent of task score; Walk MET: walking exercise metabolic equivalent of task score; total MET: total exercise metabolic equivalent of task score.

p < 0.05; **p < 0.01.

Type D personality as a predictor of walking behaviour and total exercise MET score (categorical analysis)

Based on the previous significant t-test results, two hierarchical multiple regression analyses were performed with walking and total MET score as the dependent variables. First, considering walking, demographic factors were entered in step 1 of the multiple regression (age and gender). Type D was then entered at stage 2. Model 1 with age and gender as the only predictors was found to explain 0.09 per cent of the variance and was non-significant (F(2, 177) = 0.81, p = 0.45). Model 2 in which Type D was added explained significantly more variance, with a total variance explained of 4.3 per cent, F(3, 176) = 2.63, p < 0.05.

Next considering total MET score, as before, demographic factors were entered in step 1 of the multiple regression (age and gender). Type D was then entered at stage 2. Model 1 with age and gender as the only predictors was found to explain 0.2 per cent of the variance but was non-significant (F(2, 177) = 1.82, p = 0.17). Model 2 in which Type D was added explained 0.4 per cent of the variance and the model remained non-significant (F(3, 176) = 2.47, p = 0.06).

Mediation analysis: self-efficacy, Type D and physical activity

A formal mediation analysis was conducted to assess whether self-efficacy mediates the relationship between Type D and physical activity. Regression analysis showed that Type D significantly predicted walking (β = −0.19, t(188) = −2.7, p < 0.05) and self-efficacy (β = −3.1, t(188) = −4.8, p < 0.001). In addition, the mediator self-efficacy was significantly associated with walking (β = 107.5, t(188) = 2.2, p < 0.05). Mediation analyses showed that self-efficacy mediates the relationship between Type D and walking (β = −0.11, CI = −0.22 to −0.04). Furthermore, the direct effect of Type D on walking was no longer significant when controlling for self-efficacy, thus suggesting that self-efficacy fully mediates the relationship between Type D and walking. κ² = 0.05, CI = 0.02 to 0.10, demonstrating a small effect size for the mediating effect of self-efficacy on the Type D and walking behaviour relationship. Type D did not significantly predict any of the other physical activity variables, so no further mediation analysis was carried out.

Discussion

The aim of this study was to assess whether Type D individuals differ significantly from non-Type D’s in exercise behaviour and perceived self-efficacy. Furthermore, this study sought to assess whether self-efficacy mediates the relationship between Type D and physical activity. This study’s main findings were that Type D’s engage in significantly less walking and total exercise compared to non-Type D’s. Furthermore, Type D individuals had significantly lower levels of self-efficacy compared to non-Type D’s, and self-efficacy was found to fully mediate the relationship between Type D and walking behaviour.

The first aim of this study was to examine exercise behaviour among Type D and non-Type D individuals. The categorical analysis results demonstrate that Type D individuals engage in significantly less walking and total exercise compared to non-Type D individuals. When treated as a dimensional construct, Type D was significantly correlated with walking behaviour. Finally, regression analyses showed that Type D significantly predicted walking behaviour when controlling for age and gender. However, the percentage of variance explained was small. The exercise findings of this study are consistent with previous research on the effect that Type D personality has on exercise behaviour. Kupper et al. (2013) reported that Type D personality is associated with lower levels of physical activity. Likewise, in a study of Dutch individuals, Mommersteeg et al. (2010) found that Type D individuals were less likely to meet the recommended Dutch standards for physical activity. Such findings were obtained using brief measures however, whereas this study carried out a more comprehensive assessment of exercise behaviour.

This study’s findings for exercise behaviour supplement a growing body of evidence that suggests that the association between Type D and poor health is partly facilitated by Type D individuals engaging in more detrimental health practices (Williams et al., 2015). Potential interventions could therefore be aimed at modifying health behaviours among Type D individuals in an effort to optimise their overall health outcomes. In particular, attention could be paid to improving the physical activity levels of Type D individuals. The importance of this is evident in a vast range of the literature that examines the physical and mental health benefits of engaging in regular physical activity, including walking. For example, Lee et al. (2003) reported that plentiful exercise compared to low levels of exercise significantly reduces the risk of stroke incidence and mortality by 27 per cent. Similarly, a wide range of mental health benefits have been observed including reductions in stress and anxiety as well as improved mood (Fox, 1999). In addition, Armon (2014) demonstrated that physical activity may be a protective mechanism that attenuates the association between Type D personality and increased risk of job burnout.

A further aim of this study was to investigate the relationship between Type D and self-efficacy. It was found that Type D individuals have significantly lower levels of self-efficacy compared to non-Type D’s. Furthermore, the correlation analysis showed that high scores on Type D (NA × SI) were also associated with lower levels of self-efficacy. Self-efficacy has already been found to be an important determinant of a variety of health behaviours including condom use (Khumsaen and Gary, 2009) and dental hygiene (Buglar et al., 2010). In addition, Wu et al. (2015) recently demonstrated that Type D heart failure patients exhibited lower levels of self-efficacy than non-Type D patients.

A final aim of this study was to examine whether self-efficacy mediates the relationship between Type D and physical activity. This study is the first to assess this relationship and self-efficacy was found to fully mediate the relationship between Type D and walking. Such findings can only be generalised to a healthy population and will therefore require further investigation in cardiac populations. However, if the mediating effects of self-efficacy are also evident among a cardiac sample, this could open up a new pathway of interventions for Type D personality. Specifically, interventions could be aimed at increasing levels of perceived self-efficacy among Type D’s and tackling barriers to performance. Wu et al. (2015) showed that self-efficacy fully mediates the relationship between Type D and medication adherence. Taken together, the findings of this study and those from Wu et al. (2015) point to an important role for low levels of self-efficacy in helping to explain the link between Type D and negative health behaviours.

There are a number of limitations with this study. First, this study comprised a young healthy student sample which does not allow findings to be generalised to the cardiac population. In addition to this, the study relied on a self-reported measure of exercise behaviour. While the use of subjective measures of health behaviour is a common approach, self-reporting in this context can be problematic in that social desirability effects can occur. A further limitation of this study is the cross-sectional design. Future research in this area could therefore benefit from utilising more objective measures of health behaviour through the use of a walking pedometer or accelerometer. For example, Torrent et al. (2014) showed that Type D personality was associated with less total distance walked during the 6-minute walking test (6MWT) and an increased odds of quitting the 6MWT in patients with peripheral arterial disease. In addition to introducing more objective measures of health behaviour, future research should carry out this study in a cardiac population. This is important to determine whether self-efficacy mediates the relationship between Type D and health behaviours in patient samples as this could represent one potential route for intervention among Type D individuals.

To conclude, this study has added to the literature on Type D and health behaviour in a number of important ways. First, by undertaking a more comprehensive assessment of exercise than has been used before, the study has demonstrated that Type D individuals engage in significantly less physical activity than non-Type D individuals. Moreover, this study demonstrated that Type D individuals have significantly lower levels of self-efficacy compared to non-Type D’s. In addition, self-efficacy was found to fully mediate the relationship between Type D and physical activity. Overall, the current evidence provides further support that Type D individuals engage in detrimental health practices and that the concept of self-efficacy may be one possible mechanism to explain this occurrence.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship and/or publication of this article.

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(2015) Type D personality, self-efficacy, and medication adherence in patients with heart failure – A mediation analysis. Heart & Lung: The Journal of Acute Critical Care 44: 276–281.