Crohn’s Disease: Is Quality of Life Explained by the Same Factors in Male and Female Patients?
Trindade IA*, Ferreira C, Moura-Ramos M, Pinto-Gouveia J
Faculty of Psychology and Education Sciences, CINEICC – Cognitive and Behavioural Centre for Research and Intervention, University of Coimbra, Portugal.
Inês A. Trindade MSc, PhD student,
Faculty of Psychology and Education Sciences,
CINEICC – Cognitive and Behavioural Centre for Research and Intervention,
University of Coimbra, Portugal.
Received: January 03, 2017; Accepted: March 14, 2017; Published: March 17, 2017
Citation: Trindade IA, Ferreira C, Moura-Ramos M, Pinto-Gouveia J (2017) Crohn’s Disease: Is Quality of Life Explained by the Same Factors in Male and Female Patients?. Int J Chronic Dis Ther. 3(1), 52-59.
Copyright: Trindade IA© 2017. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.
Objectives: This study aimed at analysing differences between genders regarding CD clinical characteristics, emotion regulation and QoL, the predictors of psychological and physical QoL, and whether gender moderates these associations.
Methods: Ninety eight CD patients (36 males and 62 females) met the study’s inclusion criteria and filled validated self-report measures in an online platform.
Results: Female patients presented more incidence of CD symptomatology and associated medical complications. Furthermore, it was found that 61% of CD patients’ psychological QoL seem to negatively depend on CD symptomatology and the maladaptive emotion regulation processes of cognitive fusion and disengaged living. Regarding physical QoL, age, disengaged living, CD symptomatology and associated complications negatively predicted this outcome, in a model that explained 63% of its variance. Findings also demonstrated that, of all the studied factors that may influence CD patients’ QoL, gender only moderated the association between BMI and psychological QoL. While male patients’ psychological QoL was not influenced by BMI, in females, BMI presented a negative effect on this outcome. That is, for female patients, higher BMIs seem to predict lower levels of psychological QoL.
Conclusions: The present study suggests that more importance to gender differences should be given in the monitoring of CD patients, namely to body image and weight issues in female patients. It also seems relevant to address modifiable emotion regulation processes for the promotion of patients’ QoL.
2.1 Crohn’s Disease and Gender Differences
2.2 The Role of Emotion Regulation in Quality of Life
3.4 Analytic Strategy
4.1 Preliminary Analyses
4.2 Descriptive Statistics and Comparisons between Genders
4.4 Predictors of Psychological Quality of Life for CD Patients
4.5 The moderator effect of gender on the associations of clinical features and emotion regulation with psychological and physical QoL
6.Limitations and Future Directions
Crohn’s Disease; Gender Differences; Quality of Life; Cognitive Fusion; Disengaged Living.
Crohn’s Disease (CD) is a form of inflammatory bowel disease (IBD) that can cause inflammation to part or the whole digestive system from the mouth to the rectum . Common symptoms include abdominal pain, diarrhoea, fever, fatigue, and weight loss, whose intensity and frequency vary in an unpredictable course between periods of active disease and remission . Furthermore, CD causes temporary and permanent damages to the intestines, increasing the risk of colorectal cancer . There are also frequently reported associated complications such as perianal fistulas, skin rashes, arthritis, ocular inflammation, and pulmonary problems. Regarding gender distribution, it seems consensual that CD appears to affect more women than men, in a rate of 1.5:1 .
Nevertheless, literature concerning gender differences is limited and sometimes contradictory. Some studies have suggested that female patients tend to present more symptomatology severity and associated medical complications than males [21, 34]; other studies have found that gender does not seem to be a predictive factor for disease course and severity (e.g., Romberg-Camps et al., 2009 ), and that female patients tend to present less risk of developing colorectal cancer . Furthermore, while female gender was considered a risk factor for CD relapses after surgery in two studies [2, 34], another study found male patients to be atmore risk . More recently, Law and Li (2013) reported that besides more frequency of nausea and lower body mass index (BMI) in female CD patients, no significant clinical differences were found between genders. These contradictory data seem to emphasize the importance of further examining and clarifying gender differences in CD.
CD symptoms and manifestations are known to present a significant impact on the multiple spheres of quality of life (QoL), as patients usually present lower levels of QoL than the general population, even during remission (e.g., Blondel-Kucharski et al., 2001; Graff, Walker, & Bernstein, 2010 [3, 10]). Nevertheless, other factors than the debilitating symptomatology and the unpredictable course of the disease , such as psychosocial impairment and psychiatric comorbidity, have also been independently linked to decreased QoL in IBD patients [7, 15, 26, 35]. Furthermore, there are clear evidences that psychological disturbances (such as anxiety and depression) may influence symptomatology and the course of the disease, in a cycle of relapses and psychological distress (e.g., Levenstein, 2004 ; Mawdsley & Rampton, 2005 ). Indeed, psychological QoL has been considered an important variable in the course and prognosis of IBD, but nevertheless remains little analysed by related literature.
Regarding gender differences in CD patients’ QoL, most studies report that female patients present more health-related QoL and psychosocial impairment than male patients (e.g., Sainsbury, & Heatley, 2005 ; Lesuis, Befrits, Nyberg, & van Vollenhoven, 2012 ; Tabibian et al., 2015 ). Addressing these differences, some authors consider that female IBD patients display more concerns regarding body image, physical attractiveness, and romantic relationships (e.g., Maunder et al., 1999 ), and highlight the general higher propensity for depression and anxiety shown by females . Still, although it seems important to understand the underlying mechanisms of QoL for male and female CD patients, the predictors of psychological QoL for each gender have not been clearly explored and understood.
The recent and developing third wave of the cognitive-behavioural therapies (e.g., Acceptance and Commitment Therapy; Hayes, Strosahl, & Wilson, 2012 ) address psychological suffering as the result of the way one deals with external and internal events (e.g., adverse symptomatology, thoughts, emotions), rather than solely the direct experience of those events [24, 27]. That is, human psychological suffering seems to greatly depend on the emotion regulation processes one uses to manage negative experiences (such as those related with having a chronic disease). Namely, it is conceptualized that one of these processes refers to cognitive fusion, the process in which one becomes entangled with the verbal content of thoughts, interpreting them as truthful rather than sole interpretations of reality . As a consequence of taking thoughts (e.g., “I cannot go out with my friends today, I am too tired”, “This is never going to end”, “It is worthless, I will never achieve my goals because of this illness”) as true statements of reality, one’s behaviour tends to become inflexible and restricted and the person gets disconnected from important life goals and values . One’s actions thus become uncommitted and disconnected with meaningful life pursuits (e.g., being a good friend; having a good career), in a process often designated as disengaged living . In this line, these maladaptive emotion regulation processes have been associated with decreased general and psychological functioning [9, 33, 32], and therefore seem particularly relevant in the determination of IBD patients’ quality of life and psychopathological symptoms .
Given the aforementioned gaps and inconsistencies found in literature regarding gender differences in CD, the aim of the current study is to examine whether male and female CD patients present differences regarding main medical characteristics (symptomatology and associated medical complications), emotion regulation processes central to general and psychological functioning (cognitive fusion and disengaged livings), and psychological and physical QoL.
Furthermore, this study also aims to explore which factors significantly predict patients’ psychological and physical QoL, and to analyse gender differences in these associations.
This study is has a cross-sectional nature and is part of a wider investigation which aims to explore the factors that influence IBD patients’ physical and psychosocial functioning. After the ethical approval of the research by the Portuguese Association for IBD (APDI), the 556 members of this association registered as patients received an email invitation to participate in the investigation, with detailed information regarding the study’s aims, and the voluntary and confidential nature of the participation. The interested patients accessed a link to an online platform with the informed consent and test battery.
Two hundred and nine IBD patients accepted to participate in the study, signed the informed consent and filled the test battery. Of these participants, 111 patients were excluded from the present study for having a form of IBD other than Crohn’s Disease, being pregnant, or reporting other severe illness (such as breast cancer, tuberculosis and fibromyalgia) or psychiatric disorder (bipolar disorder, generalized anxiety disorder, and panic disorder).
The sample of the present study comprised 98 Portuguese patients of both genders diagnosed with CD. It included 36 male patients with ages ranging between 18 and 49 years old (M = 34.85; SD = 8.95) and with completed education from the 6th grade to PhD (Mnumber of years of education = 13.86; SD = 3.44). Concerning marital status, 50% of the male participants were single, 41.7% were married (or living together), 5.6% divorced, and 2.8% widowed. Furthermore, the sample comprised 62 female patients, aged between 19 and 50 years old (M = 33.31; SD = 7.78). Female participants’ completed years of education ranged between the 9th grade to PhD (Mnumber of years of education = 14.27; SD = 2.75). Moreover, 53.2% of these participants were single, 45.2% were married (or living together), and 1.6% divorced. No significant differences were found between genders in what concerns age (t(96) = .43; p = .671) and completed years of education (t(96) = -.65; p = .516). Also, the percentage of participants by marital status did not significantly differ by gender [x2(3, N = 98) = 2.99, p = .394].
Participants reported demographic and medical data, and filled self-report instruments. The medical data concerned current weight and height (to calculate participants’ BMI: Wt/Ht2), CD symptoms present in the last month (e.g., abdominal pain, diarrhoea, fever, weight loss), time since diagnosis, and CD related medical complications, number of hospital admissions, and undergone surgeries. Furthermore, the completed self-report measures were the following:
Cognitive Fusion Questionnaire-7 (CFQ-7; Gillanders et al., 2014 ; Pinto-Gouveia, Dinis, Gregório, & Pinto, 2014 ). The CFQ-7 was developed to assess broad cognitive fusion, i.e., the tendency for behaviour to be excessively influenced by thoughts’ verbal content. The participant is asked to rate 7 items (e.g., “It’s such a struggle to let go of upsetting thoughts even when I know that letting go would be helpful”) in a 7-point Likert scale (1: Never true; 7: Always true) according to their suitability. The CFQ-7 presented very good psychometric characteristics in the original and Portuguese validation studies. In the current study, this measure presented Cronbach’s alphas between .95 and .96.
Engaged Living Scale (ELS (Trompetter et al., 2013 ; Trindade, Ferreira, Pinto-Gouveia, &Nooren, 2015 ). The ELS is a process measure of engaged living, as defined by Acceptance and Commitment Therapy, with 16 items (e.g., “I make choices based on my values, even if it is stressful”, “I believe that my values are really reflected in my behaviour”) which the respondent assesses on a 5-point Likert scale (1: Completely Disagree; 5: Completely Agree). Items comprehend two factors: Valued Living (personal values clarity and engagement in actions consistent with those values) and Life Fulfilment (the sense one is leading a meaningful life from behaving in accordance with personal values). In the current study, we used the total score of the shorter version of the ELS (ELS-9; Trindade et al., 2015 ), which was reversed to evaluate respondents’ level of uncommitted action and disengaged living. The ELS-9 was shown to have very good psychometric properties in its Portuguese study (αtotal = .88). In the current study, the scale also presented a good Cronbach’s alpha (αtotal = .87).
World Health Organization Brief Quality of Life Assessment Scale . This is a well-known self-report measure of subjective QoL, which comprises four domains: physical QoL, psychological QoL, social relationships, and environment. Participants are asked to evaluate the questionnaire’s 26 items on a 5-point Likert scale according to their perception of their QoL. Increasing scores indicate a more positive perception of QoL. The WHOQOL-BREF has presented satisfactory psychometric characteristics in the original and Portuguese validation studies (with αs ranging between .64 and .87). In this study, it were only used the psychological and physical QoL subscales, which revealed adequate psychometric properties (with αs varying between .76 and .83).
Preliminary data analyses were performed to evaluate data’s adequacy for further analysis. Descriptive and frequency analyses were conducted to analyse the sample’s characteristics concerning medical features, emotion regulation processes, and QoL by gender. Independent samples t-test analyses were also conducted to explore the differences between samples concerning the studied variables. Furthermore, the relationships between the studied variables were analysed performing Pearson correlation coefficients . Linear multiple regressions were conducted to explore the variables that predict CD patients’ psychological QoL and physical QoL. Gender was then tested as moderator of the relationships between psychological QoL and physical QoL’s predictors using the PROCESS macro developed by Hayes (2013) . All of the aforementioned analyses were performed using IBM SPSS Statistics 20 (IBM Corp, 2011).
The values of skewness and kurtosis were examined to analyse data’s univariate and multivariate normality. The skewness values ranged from -0.43 to 0.61, and the values of kurtosis from -0.57 to 0.40. Results thus indicated that the distribution of the data was normal (Kline, 2016). Moreover, the values of the Variance Inflaction Factor (VIF) corroborated the suitability of the data (VIF < 5).
The medical characteristics of the sample are presented in Table 1 and Table 2. Table 1 presents the percentage of medical features (BMI, time since diagnosis, associated medical complications, number of hospital admissions, and number of surgeries) for each gender. The most reported associated complications by males were perianal fistulas and respiratory problems (e.g., sinusitis), while female patients mostly reported osteoarticular complaints (e.g, osteoporosis, arthritis), dermatological problems (e.g., psoriasis), and duodenal ulcers.
Furthermore, Table 2 shows that no significant differences were found between genders regarding time since diagnosis (t(96) = 0.78; p = .635), number of surgeries (t(43.36) = 1.34; p = .188), and number of hospital admissions (t(96) = 0.79; p = .434). However, significant differences were found between genders concerning BMI (t(96) = 2.47; p = .015), CD symptomatology (t(96) = -2.83; p = .006), and associated medical complications (t(79.56) = -2.41; p = .019), with female patients reporting significantly higher levels of these variables except for BMI.
Regarding the studied emotion regulation processes, it was verified that genders did not significantly differ in levels of cognitive fusion (t(96) = 0.65; p = .519) and disengaged living (t(57.44) = 1.52; p = .135). In addition, psychological QoL (t(96) = -0.50; p = .616) and physical QoL (t(96) = 1.45; p = .152) also presented similar levels for both genders.
Table 2. Means (M), Standard Deviations (SD), and Comparison between Male Patients (n = 36) and Female Patients (n = 62) Concerning Medical Features, Emotion Regulation Processes, Psychological Quality of Life, and Physical Quality of Life.
Results from the correlation analyses (Table 3) demonstrated that CD symptomatology, cognitive fusion, and disengaged living were highly associated with lower levels of psychological QoL and physical QoL. Furthermore, psychological QoL also presented negative correlations with BMI and associated medical complications, which in turn was positively linked with BMI and CD symptomatology. In turn, physical QoL was negativelylinked to age and positive correlated with associated medical complications.
Table 3. Intercorrelation Scores on Self - Report Measures and Self - Reported Medical Data (N = 98).
Regarding the studied emotion regulation processes, results demonstrated that cognitive fusion and disengaged living presented positive correlations between each other. Additionally, higher levels of cognitive fusion were associated with higher incidence of CD symptomatology.
In order to explore which variables predict CD patients’ psychological QoL and physical QoL, two multiple linear regressions (Table 4) were conducted taking into consideration the results from the correlation analyses (N = 98).
Thus, BMI, associated medical complications, CD symptomatology, cognitive fusion, and disengaged living were tested as predictors of psychological QoL. Furthermore, age, associated medical complications, cognitive fusion, disengaged living, and CD symptomatology were examined as predictors of physical QoL.
Results regarding psychological QoL revealed that BMI (β = -.13; p = .062) and associated medical complications (β = -.05; p = .519) were not significant predictors of the model. Nonetheless, CD symptomatology (β = -.22; p = .003), cognitive fusion (β = -.30; p < .001), and disengaged living (β = -.47; p < .001) were found to be significant predictors of lower levels of psychological QoL. This model was significant [F(5, 92) = 28.66; p < .001] and explained 61% of the variance of psychological QoL.
Concerning physical QoL, results demonstrated that a significant model was also produced [F(5.92) = 30.64; p < .001], which showed that all the predictors were significant except for cognitive fusion (β = -.14; p = .064). Indeed, age (β = -.15; p = 027), associated medical complications (β = -.23; p = .001), disengaged living (β = -.37; p < .001), and CD symptomatology (β = -.40; p < .001) presented negative effects on physical QoL, in a model that accounted for 63% of this construct.
In order to explore gender differences, gender was tested as a moderator of the relationships between the associations of clinical features and emotion regulation with psychological and physical QoL, using the PROCESS macro for SPSS (Model 1; Hayes et al., 2013 ). Thus, in these analyses, gender was proposed as moderator, psychological QoL or physical QoL as dependent variables (DV), and each variable of each regression model (Table 4) was proposed as independent variable (IV),while the other variables were controlled as covariates. For example, in order to analyse the moderator effect of gender on the association between BMI and psychological QoL, BMI was included as IV, gender as moderator, psychological QoL as DV, and CD symptomatology, cognitive fusion and disengaged living as covariates. This procedure was repeated so all variables included as IVs in the conducted multiple regression models (Table 4) would be tested as IV in these moderation analyses.
Table 4. Linear Multiple Regressions to Analyse the Predictors of Psychological QoL and Physical QoL (N = 98).
The only significant moderator effect that was found referred to the association between BMI and psychological QoL. Results revealed that the interaction gender X BMI was significant [F(1, 90) = 4.73; p = .032] and simple slope analysis demonstrated that the effect of BMI on psychological QoL was significant for female patients with an effect of -.73 (t = -2.64, p = 0.10), while males presented a non-significant effect (t = 1.07, p = .286). Graph 1 represents the effect of BMI on psychological QoL, in male and female patients.
Graph 1. Grapshic representation of the effect of BMI on psychological QoL, in male (n = 36) and female CD patients (n = 62).
CD is a chronic illness that causes significant psychosocial and QoL impairment, which in turn is known to increase the level of clinical CD manifestations in a cycle of inflammation and emotional distress. Nevertheless, although some studies recognize that male and female patients might differ regarding QoL’s predictors, research on gender differences in CD patients is limited and inconsistent, and little is known about the determinants of patients’ well-being according to gender. Therefore, the present study aimed at analysing the differences between male and female patients regarding main CD clinical characteristics, emotion regulation processes and QoL, the predictors of psychological and physical QoL, and whether gender moderates these associations. This study comprised a sample of 98CD patients which were recruited via an online platform through the Portuguese Association for IBD (APDI). Participants reported demographic and medical information and filled validated self-report measures.
Results mirrored previous literature as it was demonstrated that female patients presented more incidence of CD symptomatology and associated medical complications (e.g., Wagtmans et al., 2001 ; Maunder et al., 2009) and lower BMIs . Furthermore, genders did not present significant differences regarding time since the CD diagnosis, number of hospitalizations, number of undergone surgeries, and on levels of maladaptive emotion regulation processes (cognitive fusion and disengaged living). Interestingly, male and female patients also did not present differences concerning psychological QoL and physical QoL, a finding that differs from preceding literature which suggests that female patients display more psychosocial and physical impairment than males. This finding may indicate that male and female CD patients deal similarly with life difficulties, using similar levels of emotion regulation processes which may further explain similar levels of quality of life.
Regarding the conducted correlation analyses demonstrated that, as expected (e.g., Devlen et al., 2014 ), CD symptomatology and associated medical complications was linked to lower levels of psychological and physical QoL. Furthermore, the present study unveils that, engagement in cognitive fusion and disengaged living is highly associated with psychological and physical impairment. Psychological QoL additionally presented negative correlations with BMI and physical QoL was negatively linked to age. Taking into consideration these results, multiple linear regressions were conducted in order to explore which variables predict psychological QoL and physical QoL.
It was found that 61% of the variance of patients’ psychological QoL seems to negatively depend on CD symptomatology and the maladaptive emotion regulation processes of cognitive fusion and disengaged living. Indeed, it seems that the debilitating symptoms of CD are not the only determinants of psychological QoL, as fusion with thoughts’ verbal content and the engagement in behaviours uncommitted with one’s personal values emerge as the best predictors of the model. This finding highlights the importance of implementing psychological interventions aiming to develop cognitive defusion (the ability of observing thoughts as transient and subjective inner experiences) and the clarification and promotion of personal values and consistent actions.
Furthermore, age, associated medical complications, disengaged living, and CD symptomatology emerged as predictors of 63% of the variance of physical QoL (in that order of magnitude). In fact, although CD symptomatology was the best predictor of the model, the process of disengaged living also seems to present an important role in the determination of patients’ physical QoL. This may be explained by the commitment in actions consistent with values related to health protection and promotion.
In order to explore whether there were gender differences concerning the impact each variable tested as predictor in the previous analyses on quality of life, gender was tested as moderator of these relationships. It was found that gender did not significantly moderate the impact of CD symptomatology, associated medical complications, cognitive fusion, and disengaged living on psychological and physical QoL. The impact of age on physical QoL was also not moderated by gender. These results suggest that there are no gender differences regarding the impact the aforementioned variables have on CD patients’ QoL, i.e., that gender does not influence the effect these variables hold on psychological and physical functioning. This finding may suggest that for the same level of CD symptomatology, associated medical complications, cognitive fusion, or disengaged living, men and women tend to present the same level of quality of life.
However, that does not seem to be the case regarding BMI’s impact on psychological QoL. This association was significantly moderated by gender: while male patients’ psychological QoL was not influenced by BMI, in females BMI presented a negative effect on this outcome. That is, for female patients, higher BMIs seem to predict lower levels of psychological QoL. This seems to be an important finding that may be explained by the central role of weight for the self-evaluation and well-being of women from modern Western cultures. Indeed, this finding might be linked to the pressure women tend to feel to be thinner and present smaller body figures, and thus to the high incidence of a “normative body discontent”among females from these societies (e.g., Mond et al., 2013 ; Ferreira & Trindade, 2014 ).
Limitations and Future Directions
In order to address some limitations of the present study, future studies should also test our results in larger samples and different populations, such as patients with ulcerative colitis or other chronic illnesses, and patients from other cultures. It is also important to acknowledge that the used data collection method (through an online platform) may have comprised the generalization of the sample; indeed, it is possible that the present sample comprises patients more educated than the Portuguese overall population with IBD. Future studies should thus be conducted with different procedures. Further, the instruments used to assess cognitive fusion (CFQ-7) and disengaged living (ELS) are general measures of those processes. Specific measures should be created to specifically evaluate the level of some emotion regulation processes in the particular context of IBD-related experiences. Besides, since this study’s variables were intentionally limited to facilitate the readability of the analyses, other emotion regulation processes (e.g., experiential avoidance, decentering) should be explored as other possible predictors of patients’ QoL. Finally, given that the cross-sectional nature of this study does not allow causal conclusions, it seems important that future research would also focus on the longitudinal examination of the studied relationships.
Nevertheless, the present study suggests that more importance to gender differences should be given in the clinical monitoring of CD patients, namely, to females’ body image and weight issues. Furthermore, our results also highlight the pertinence of addressing modifiable emotion regulation processes (such as cognitive fusion and disengaged living) in order to promote patients’ QoL. In this line, it may be useful to include psychological assessments and interventions in the general health care of these patients, as it might substantially improve their psychological and physical functioning and therefore diminish the harmful impact of CD on their lives.
We thank the Portuguese Association for IBD (Associação Portuguesa para a Doença Inflamatória do Intestino; APDI) for their help during the recruitment process of this investigation’s sample. Research by the first author (Inês A. Trindade) is supported by a Ph.D. Grant (SFRH/BD/101906/2014) sponsored by FCT (Portuguese Foundation for Science and Technology).
- Baumgart DC, Sandborn WJ (2012) Crohn’s disease. Lancet. 380(9853): 1590–605. doi:10.1016/S0140-6736(12)60026-9.
- Bernell O, Lapidus A, Hellers G (2000) Risk Factors for Surgery and Postoperative Recurrence in Crohn’s Disease. Ann Surg. 231(1): 38-45. doi: 10.1097/00000658-200001000-00006.
- Blondel-Kucharski F, Chircop C, Marquis P, Cortot A, Baron F, et al., (2001) Health-related quality of life in Crohn’s disease: A prospective longitudinal study in 231 patients. Am J Gastroenterol. 96(10): 2915–2920. doi:10.1111/j.1572-0241.2001.4681_b.x
- Canavarro MC, Serra AV, Simoes MR, Rijo D, Pereira M, et al., (2009) Development and psychometric properties of the World Health Organization Quality of Life Assessment Instrument (WHOQOL-100) in Portugal. Int J Behav Med. 16(2): 116–124.
- Cohen J, Cohen P, West S, Aiken L (2003) Applied multiple regression/correlation analysis for the behavioural sciences 3rd (edn), Lawrence Erlbaum Associates: New Jersey.
- Devlen J, Beusterien K, Yen L, Ahmed A, Cheifetz AS, et al., (2014) The burden of inflammatory bowel disease: a patient-reported qualitative analysis and development of a conceptual model. Inflamm Bowel Dis. 20(3): 545-552. doi:10.1097/01.MIB.0000440983.86659.81
- Drossman DA, Patrick DL, Mitchell CM, Zagami EA, Appelbaum MI (1989) Health-related quality of life in inflammatory bowel disease-Functional status and patient worries and concerns. Dig Dis Sci. 34(9): 1379–1386. doi:10.1007/BF01538073
- Ferreira C, Trindade IA (2014) Body image-related cognitive fusion as a main mediational process between body-related experiences and women’s quality of life. Eat Weight Disord. 20(1): 91-97.doi: 10.1007/s40519-014-0155-y.
- Gillanders D, Bolderston H, Bond FW, Dempster M, Flaxman PE, et al., (2014) The Development and Initial Validation of the Cognitive Fusion Questionnaire. Behav Therapy. 45(1): 83-101. doi:10.1016/j. beth.2013.09.001.
- Graff LA, Walker JR, Bernstein CN (2010) It’s Not Just About the Gut : Managing Depression and Anxiety in Inflammatory Bowel Disease. Prac Gastroenterol. 34(7): 11–25.
- Hayes AF (2013) Introduction to mediation, moderation, and conditional process analysis: A regression-based approach. NY: The Guilford Press, NewYork.
- Hayes SC, Strosahl KD, Wilson KG (2012) Acceptance and commitment therapy: The process and practice of mindful change. 2nd (edn), The Guilford Press: New York.
- Hofer B, Böttger T, Hernandez-Richter T, Seifert JK, Junginger T (2000) The impact of clinical types of disease manifestation on the risk of early postoperative recurrence in Crohn’s disease. Hepato-gastroenterology. 48(37): 152-155.
- IBM Corp (2011) IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp.
- Janke KH, Klump B, Gregor M, Meisner C, Haeuser W (2005) Determinants of life satisfaction in inflammatory bowel disease. Inflamm Bowel Dis. 11(3): 272–286.
- Kline RB (2016) Principles and practice of structural equation modeling. 4th (edn), New York: Guilford.
- Law ST, Li KK (2013) Age-related differences in the clinical course of Crohn’s disease in an Asian population: a retrospective cohort review. Indian Pediatr. 50(12): 1148–1152. doi:S097475591300305.
- Lennard-Jones J (1968) Medical aspects of Crohn’s disease. Proc R Soc Med. 61(1): 81-83.
- Lesuis N, Befrits R, Nyberg F, van Vollenhoven RF (2012) Gender and the treatment of immune-mediated chronic inflammatory diseases: rheumatoid arthritis, inflammatory bowel disease and psoriasis: an observational study. BMC Medicine. 10(1): 82. doi:10.1186/1741-7015-10-82.
- Levenstein S (2004) Embracing complexity: what determines quality of life in inflammatory bowel disease? Eur J Gastroenterol. 16(12): 1253–1255. doi:10.1097/00042737-200412000-00002
- Maunder R, Toner B, De Rooy E, Moskovitz D (1999) Influence of sex and disease on illness-related concerns in inflammatory bowel disease. Can J Gastroenterol. 13(9): 728–732.
- Mawdsley JE, Rampton DS (2005) Psychological stress in IBD: new insights into pathogenic and therapeutic implications. Gut. 54(10): 1481–1491. doi:10.1136/gut.2005.064261.
- Mond J, Mitchison D, Latner J, Hay PJ, Owen C (2013) Quality of life impairment associated with body dissatisfaction in a general population sample of women. BMC Public Health. 13: 920. doi:10.1186/1471-2458-13-920.
- Pinto-Gouveia J, Duarte C, Matos M, Fráguas S (2014) The protective role of self-compassion in relation to psychopathology symptoms and quality of life in chronic and in cancer patients. Clin Psychol Psychother. 21(4): 311-323. doi:10.1002/cpp.1838.
- Romberg-Camps MJL, Dagnelie PC, Kester ADM, Hesselink-van de Kruijs MA, Cilissen M, (2009) Influence of phenotype at diagnosis and of other potential prognostic factors on the course of inflammatory bowel disease. Am J Gastroenterol. 104(2): 371–383. doi: 10.1038/ajg.2008.38
- Sainsbury A, Heatley RV (2005) Review article: psychosocial factors in the uality of life of patients with inflammatory bowel disease. Aliment Pharmacol Ther. 21(5): 499–508. doi:10.1111/j.1365-2036.2005.02380.x
- Segal Z, Williams M, Teasdale J (2002) Mindfulness-based cognitive therapy for depression: A new approach to preventing relapse: Book review. Cognit Behav Ther. 31(4): 193–194.
- Söderlund S, Granath F, Broström O, Karlén P, Löfberg R, et al., (2010) Inflammatory Bowel Disease Confers a Lower Risk of Colorectal Cancer to Females Than to Males. Gastroenterol. 138(5): 1697-703.doi:10.1053/j. gastro.2010.02.007
- Solomon MB, Herman JP (2009) Sex differences in psychopathology: Of gonads, adrenals and mental illness. Physiol Behav. 97(2): 250-258. doi:10.1016/j.physbeh.2009.02.033
- Tabibian A, Tabibian JH, Beckman LJ, Raffals LL, Papadakis KA, et al., (2015) Predictors of health-related quality of life and adherence in Crohn's disease and ulcerative colitis: implications for clinical management. Dig Dis Sci. 60(5): 1366-1374. doi: 10.1007/s10620-014-3471-1
- Trindade IA, Ferreira C, Pinto-Gouveia J (2015) Ulcerative colitis symptomatology and depression: The exacerbator role of maladaptive psychological processes. Dig Dis Sci. 60(12): 3756-3763. doi: 10.1007/s10620-015-3786-6
- Trindade IA, Ferreira C, Pinto-Gouveia J, Nooren L (2015) Clarity of personal values and committed action: Development of a shorter Engaged Living Scale. J Psychopathol Behavior Assesment. doi: 10.1007/s10862-015-9509-7
- Trompetter HR, Ten Klooster PM, Schreurs KMG, Fledderus M, Westerhof GJ, et al., (2013) Measuring values and committed action with the Engaged Living Scale (ELS): psychometric evaluation in a nonclinical sample and a chronic pain sample. Psychol Assess. 25(4): 1235–46. doi:10.1037/a0033813
- Wagtmans MJ, Verspaget HW, Lamers CB, van Hogezand RA (2001) Gender-related differences in the clinical course of Crohn’s disease. Am J Gastroenterol. 96(5): 1541–1546. doi:10.1111/j.1572-0241.2001.03755.x
- Walker JR, Ediger JP, Graff LA, Greenfeld JM, Clara I, et al., (2008) The Manitoba IBD cohort study: A population-based study of the prevalence of lifetime and 12-month anxiety and mood disorders. Am J Gastroenterol. 103(8): 1989-1997. doi:10.1111/j.1572-0241.2008.01980.x
- The WHOQOL Group (1998) The World Health Organization Quality of Life Assessment (WHOQOL): Development and general psychometric properties. Soci Sci Med. 46(12): 1569-1585. doi:10.1016/S0277-9536(98)00009-4