Psychological Reports: Sociocultural Issues in Psychology 2014, 114, 3, 927-946. © Psychological Reports 2014

FACTOR STRUCTURE OF QUALITY OF LIFE IN ADOLESCENTS1 MARIA OLEŚ Institute of Psychology The John Paul II Catholic University of Lublin, Poland Summary.—The goal was to present the factor structure of subjective quality of life in adolescents, investigated by means of four questionnaires: the Youth Quality of Life–Research Version (YQOL–R), the Quality of Life Profile–Adolescent Version (QOLP–AV), the KIDSCREEN–52 Questionnaire, and the Quality of Life Questionnaire for Children and Adolescents (QLQ–CA). Two exploratory factor analyses conducted on the results obtained from two samples of adolescents: healthy, N = 252 (144 girls, 108 boys), and chronically ill, suffering from several illnesses, N = 189 (118 girls, 71 boys). Both factor analyses revealed four-factor solutions, each explaining about 60% of the total variance. The factor structure for the healthy group approximately reproduced the structures of the four questionnaires: Developmental quality of life (23%), Health and Well-being (16%), Relational quality of life (14%), and Ego strength (8%). The factor structure for the chronically ill group was similar for three factors: Developmental quality of life (22%), Harmony between the self and the environment (14%), and Coping and Support (12%), but different for another one: Health-related quality of life (10%). The discussion focuses on the specific nature of four aspects of quality of life observed in the healthy sample and their similarities to and differences from the factors in the chronic patients' sample.

Studies on quality of life in adolescents are related to the assessment of the condition of health as well as the physical and mental states of adolescents who receive medical care. Quality of life is defined with reference to the World Health Organization's concept of health as a state of complete physical, mental, and social well-being, and to the salutogenic interpretation which focuses on the individual's resources and development capacities. According to the WHO, quality of life is “the individuals’ perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards, and concerns. It is a broad-ranging concept affected in a complex way by the person's physical health, psychological state, level of independence, social relationships, and their relationship to salient features in their environment” (The WHOQOL Group, 1995, p. 1405). Health-related quality of life is defined in a similar way as “a multidimensional construct covering physical, emotional, mental, social and behavioral components of well-being and function as perceived by patients and/or other individuals” (KIDSCREEN Group Europe, 2006, p. 16). Health-related quality of life 1 Address correspondence to M. Oleś, Institute of Psychology, The John Paul II Catholic University of Lublin, Al. Racławickie 14, 20-950 Lublin, Poland or e-mail ([email protected]).

DOI 10.2466/17.15.PR0.114k26w9

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ISSN 0033-2941

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(HRQOL) refers to the effect that an illness and its treatment exert on the individual's functioning in various areas of life (Schipper, 1990; Spieth & Harris, 1996; Ravens-Sieberer & Bullinger, 1998; Seid, Varni, Rode, & Katz, 1999; Ronen, Rosenbaum, Law, & Streiner, 2001). Both definitions emphasize the subjective and complex character of quality of life (Felce & Perry, 1995; The WHOQOL Group, 1995; Schalock, 2000; Eiser & Morse, 2001; Ware, 2003), which comprises physical, psychological, interpersonal, environmental, spiritual, and personal independence. Most studies on the quality of life in adolescents refer to the WHO approach (e.g., Patrick, Edwards, & Topolski, 2002). Any assessment of healthrelated quality of life in adolescents should take into account their developmental needs, previous experiences, expectations for the future, preferences of activities, and possible limitations caused by the state of health (RavensSieberer & Bullinger, 1998; Seid, Varni, & Kurtin, 2000; Eiser & Morse, 2001). The psychological situation of adolescents with illness differs from that of their healthy peers, and the illness influences their quality of life (PetersenEwert, Erhart, & Raven-Sieberer, 2011). However, the developmental needs of both healthy and ill adolescents are the same; this fact implies the existence of similar structure of quality of life in these populations. Theory and research of quality of life in adolescents emphasize two approaches, holistic and health-related; both approaches include physical, emotional, mental, social, and behavioral aspects. For example, the KIDSCREEN was constructed for assessment of health-related quality of life and the instrument is applicable in the general population of adolescents, while the QOLP–AV was constructed on the basis of empirical data originating from the general population but is applicable both in healthy groups and in the population of patients with disabilities (Zekovic & Renwick, 2003). The goal was to address the following questions: (1) what is the structure of subjective quality of life in adolescents, and (2) to what extent are these structures similar in healthy and chronically ill adolescents? In other words, what dimensions constitute the broadly understood subjective quality of life according to the factor-analyzed data originating from healthy and ill adolescents? — a crucial problem for measuring subjective quality of life (Ravens-Sieberer, Erhart, Wille, Wetzel, Nickel, & Bullinger, 2006). The issue is, therefore, to study the factor structure of quality of life assessed by means of four methods, in both ill and healthy adolescents. Hypothesis 1. Providing that the WHO definition implies an universal and holistic approach to the quality of life, one can expect that the general domains of (a) physical health, (b) psychological state, (c) independence, (d) social relationship, and (e) relation to environment, constitute the five dimensions of quality of life in adolescents.

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Hypothesis 2. In both healthy and ill adolescents, the factor structure is similar concerning the number and general meaning of factors although perhaps somewhat different in their particular content (variables with high factor loadings). This implies a comparison of the structures obtained for ill and healthy participants. Such an investigation tends to answer the question whether the selected methods measure the same phenomenon or different aspects of life quality, or to what extent different operationalizations of life quality are coherent, redundant, or unique. Moreover, while this study answers the two important questions mentioned above, it can delineate a general structure of quality of life. Until now, the research of the factor structures of quality of life has focused on not more than two approaches and methods (e.g., Raphael, Rukholm, Brown, Hill-Bailey, & Donato, 1996b; Raphael, Waalen, & Karabanow, 2001; Davis, Mackinnon, Davern, Boyd, Bohanna, Waters, et al., 2013) or on broader sets of variables and quality of life among the others (e.g., Wu & Yao, 2007; Kojima, Kojima, Ishiguro, Oguchi, Oba, Tsuchiya, et al., 2009). This study will compare four different and well-known approaches to the assessment of quality of life, which deliver comprehensive overviews of the empirical structure of the phenomena under investigation. METHOD Participants The total group of healthy teenagers consisted of 333 participants (178 girls, 53.5%), ages 11–18 yr. Some participants’ data (n = 55) were eliminated due to incomplete answers, and 26 others due to unusual results deviating from the average by more than three SD. Thus, the factor analysis was computed on the results of 252 participants, 144 girls (M age = 15.2 yr., SD = 2.5) and 108 boys (M age = 14.8, SD = 2.2). The research was conducted in several classes from some elementary schools (Grades 5 and 6), middle schools, and high schools located in the towns and villages in the east part of the country. The study began with the Youth Quality of Life–Research Version questionnaire (YQOL–R); then the participants completed the remaining two questionnaires and the Quality of Life Questionnaire for Children and Adolescents (QLQ–CA) as the last one. The total sample of adolescents with chronic illness consisted of 266 patients (164 girls, 62%), ages 11–18 yr. Some participants (n = 57) were eliminated due to incomplete answers, and 20 others due to unusual results deviating from the average by more than 3 SD. For the computations, the results of 189 participants were taken into account, including 118 girls (M age = 14.8 yr., SD = 1.6) and 71 boys (M age = 14.6, SD = 1.7). All the participants were hospitalized at Pediatric Clinic in Lublin (Poland) and came from the southeast-

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earn part of the country. Their illnesses were: type 1 diabetes (n = 51), obesity (n = 40), idiopathic short stature (n = 16), functional headache (n = 28), thyroid disease (n = 16), anorexia nervosa (n = 10), neurological disorders (n = 14), chronic gastric disorders (n = 10), and epilepsy (n = 4). The chronic medical conditions were diagnosed by a physician, and the participants were surveyed under hospital conditions in groups of several persons. The questionnaires were given in the same order as in the case of the healthy group. Measures The data on quality of life and health-related quality of life were collected by using Polish versions of the questionnaires. All of the instruments were prepared in cooperation with their original authors. The adaptation procedure consisted of a professional translation, a back translation, a correction of selected items, a pilot study, and analysis of the research data on the angle of psychometric properties of the scales (Oleś, 2010). The Youth Quality of Life Instruments–Research Version (YQOL–R) by Patrick, et al. (2002) are self-assessment methods developed to measure quality of life in youth ages 11–18 yr. The YQOL–R consists of 41 perceptual items concerning internal experiences and the subjective evaluation of quality of life in four areas: Sense of Self, Relationships, Environment, and General Quality of Life. Sample items include: “I am pleased with how I look,” “I am happy with the friends I have,” “I like my neighborhood,” “I enjoy my life.” A respondent answers questions on an 11-point scale (anchors 0: Strongly disagree, 10: Strongly or very much agree). The results are the total score and the scores on four subscales. The psychometric properties of this instrument have been proved valid and reliable (Patrick, et al., 2002). Cronbach's α internal consistency coefficients were between .81 to .89 for four domains and .94 for the total score. One-week test-retest stability coefficient for the total score was .78 for healthy adolescents. All subscales and the total score (r = .73) correlated highly and positively with the KINDL2 (an instrument measuring the same construct of perceived quality of life), and negatively with Children's Depression Inventory (CDI) (r = –.58). The YQOL–R is a sensitive measure of symptom status and discriminates healthy and chronic condition samples (Patrick, et al., 2002; Topolski, Edwards, & Patrick, 2002). Cronbach's α coefficients for the subscales of the Polish adaptation ranged in this study from .73 to .92 for the healthy group and from .85 to .90 for the group with chronic conditions, and were, respectively, .94 and .96 for the total score. The oneyear test-retest stability coefficients for adolescents without chronic conditions ranged from .43 to .67 for subscales, and for the total score .60. Quality of life correlates negatively with depression (CDI) r = –.58 (Oleś, 2010). KINDL - Questionnaire for Measuring Health-Related Quality of Life in Children and Adolescents 2

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The Quality of Life Profile–Adolescent Version (QOLP–AV) by Raphael, Rukholm, et al. (1996) is a generic measure of health and well-being. The instrument is an operationalization of the conceptual model of quality of life: “How good is your life for you?” and it measures an individual's possibilities in three dimensions of human existence: Being, Belonging, and Becoming (Raphael, D’Amico, Brown, & Renwick, 1996; Renwick & Brown, 1996). The model emphasizes the holistic nature of quality of life and focuses on wellness rather than illness. The QOLP–AV consists of 54 items in three global domains, six in each of nine subdomains. Being includes the following subdomains: physical, psychological, and spiritual; Belonging refers to the individual's connection with the environment in physical, social, and community areas; Becoming concerns achieving personal goals, hopes, and aspirations and taps practical becoming, leisure, and growth (Raphael, D’Amico, et al., 1996; Bradford, Rutherford, & John, 2002). Examples of items in the QOLP–AV3 are: “My nutrition and the food I eat,” “Being free of worry and stress,” “The house or apartment I live in,” “Being close to people in my family,” “Having enough money,” “Doing things around my house,” “Being able to cope with changes in my life.” Each statement is rated for both individual importance and satisfaction on a five-point Likert-type scale (anchors 1: Not at all and 5: Extremely). The quality of life scores for each domain and subdomain were computed according to the criteria specified by Raphael, Rukholm, et al. (1996). The quality of life scores ranged from –3.33 to + 3.33 with the scores above 0 indicating positive quality of life, and those below 0, a negative quality of life (Raphael, Rukholm, et al., 1996)4. The internal consistency of the QOLP–AV is high; Cronbach's α ranged from .83 to .87 for domains, and from .94 to .97 for the total scale. Quality of life scores positively correlated with self-esteem, life satisfaction, and social support (from .51 to .56; Raphael, Rukholm, et al., 1996). The instrument has established factor validity that empirically supports Raphael's conceptualization of quality of life (Bradford, et al., 2002). Cronbach's α coefficients of the Polish version of the QOLP–AV in the current study of healthy adolescents varied from .80 to .88 for subdomains, and were .93 for each domain and .97 for the total score. In the study of adolescents who were ill, the alpha coefficients ranged from .77 to .89 for subdomains, from .91 to .93 for the domains, and .96 for the total score (Oleś, 2010). The questionnaire also includes 18 items relating to perceived control over and opportunities for improvements in the areas assessed, which are not relevant to this study. 4 Importance scores serve as a weight for converting satisfaction scores into quality of life scores: (QOL) = (Importance Score/3) × (Satisfaction Score-3). QOL scores range from –3.33 (“Extremely Important” items, “No Satisfaction at All”) – + 3.33 (“Extremely Important” items, “Extremely satisfied”). To illustrate, an individual who describes an item as “very important” (4) with high satisfaction (4) receives a QOL score of 1.33 (4/3 × 4–3)” (Raphael, Rukholm, et al., 1996, p. 368). 3

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The KIDSCREEN–52 (Health-Related Questionnaire for Children and Adolescents) is the first truly cross-national, generic, health-related quality of life measure developed for children and adolescents (Ravens-Sieberer & Bullinger, 1998). It consists of 52 items grouped in 10 dimensions: Physical Wellbeing, Psychological Well-being, Moods and Emotions, Self-perception, Autonomy, Parent Relations and Home Life, Financial Resources, Social Support and Peers, School Environment, and Social Acceptance (Bullying). Sample of the items: “Have you been worried about the way you look?”, “Have you been happy at home?”, “Have you spent time with your friends?” The items assess either the frequency of certain feelings/behaviors or the intensity of particular attitudes that appeared in the last week using a 5-point Likert-type scale (anchors 1: Not at all/Never, and 5: Extremely/Always). The scores in each dimension are computed and transformed into T scores. The KIDSCREEN–52 questionnaire has proved acceptable as far as internal consistency reliability and validity are concerned. Cronbach's αs of measured dimensions ranged between .77 and .89. Convergent validity of the KIDSCREEN is also satisfactory. Pearson's correlation coefficients between all scales and the YQOL–S questionnaire ranged from .24 to .61 (Ravens-Sieberer & Bullinger, 1998; The KIDSCREEN Group Europe, 2006). In the current study, reliability was marginal to satisfactory for all subscales (coefficients α from .77 to .93 for the healthy group and from .63 to .93 for adolescents with chronic conditions). Pearson's correlation coefficients between all scales and the QOLP– AV ranged from .22 to .42, and between the KIDSCREEN and the QLQ–CA were from .27 to .54 (Oleś, 2010). The instrument has confirmed factor validity (Robitail, Ravens-Sieberer, Simeoni, Rajmil, Bruil, Power, et al., 2007; Tzavara, Tzonou, Zervas, Ravens-Sieberer, Dimitrakaki, & Tountas, 2012). The Quality of Life Questionnaire for Children and Adolescents (QLQ–CA) is a modified version of the QOL-Q developed by Schalock and Keith (1993). The original measure is based on the holistic model of QOL understood as the result of an interaction between a person and the environment (Schalock, 2000). The QLQ–CA consists of 40 items, with 10 items in each of four areas: Life Satisfaction, Skills/Competencies, Possibility of Action/Independence, Social Belonging/Community Integration. Afterwards, a fifth dimension was added: Health-related Quality of Life scale (10 items) (Oleś, 2010). Therefore, the final version of the questionnaire consists of 50 items in five subscales. The statements use a three-point scale in the assessment procedure. The sample items are: “How much fun and enjoyment do you get out of life? (Lots, Some, Not much)”, “Do you have friends over to visit your home? (Fairly often, Sometimes, Rarely, Never).” The total score ranges from 10 to 120, while the scores in each of the five domains vary from 10 to 30. The instrument has good reliability and validity. Cronbach's α in healthy adolescents were from .69 to .84 for the subscales, .94 for the total score; in ill par-

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ticipants they were from .76 to .83, and .90 for the total score. The QOL-CA has distinguished well between healthy and sick adolescents (Oleś, 2010). The validity of the instruments is supported by their intercorrelations (Table 1). Statistical Analyses The SPSS Version 17 was used for data analysis. First, the data were checked for the possibility of outliers. This procedure eliminated some participants from each group. Second, the quality of sampling was evaluated for both groups using Kaiser-Meyer-Olkin and Bartlett's test of sphericity. The KMO for the healthy and the sick were .920 and .892, respectively, while Bartlett's test was significant for both groups (p < .001). Third, the exploratory factor analysis, namely principal component analysis with Varimax rotation, was computed on the results of the healthy group. According to the scree test, a four-factor solution was accepted (communalities for 28 variables also suggested that). Fourth, confirmatory factor analysis (CFA) was applied to investigate if the factor structure extracted for healthy adolescents fit on to the (data of) chronic patients. The result showed that while the model extracted for the latter group did not fit the data of the former group one, the goodness of fit was not too poor (χ2/df = 2.48, RMSEA = 0.089, GFI = 0.741, CFI = 0.825, NFI = 0.74). Finally, following this result (and providing the same number of factors for each group), the same kind of factor analysis was computed on the results of chronically ill patients with a defined number of four factors. At the end, two factor structures were compared by means of Procrustes rotation and Tucker's coefficients of congruence. TABLE 1 DESCRIPTIVE STATISTICS AND CORRELATIONS (WITH 95% CONFIDENCE INTERVALS) BETWEEN TOTAL SCORES IN FOUR QUALITY OF LIFE MEASURES Questionnaire 1. YQOL–R 95%CI, r 2. QOLP–AV 95%CI, r

Healthy Group

Chronic Patients

M

M

SD

SD

Correlations 1

76.90 13.12 74.08 14.77 1.13

0.90

1.05

0.83

.46 .34, .57

2

3

4

.39 .28, .49

.55 .46, .63

.62 .54, .69

.49 .39, .58

.40 .30, .50

3. KIDSCREEN–10 95%CI, r

45.16

9.60 41.97

6.95

.54 .43, .64

.39 .26, .51

4. QOL-CA 95%CI, r

96.14

9.82 95.65

9.74

.67 .58, .74

.31 .18, .44

.54 .44, .62 .49 .37, .59

Note.—Correlations for healthy participants (n = 252) are presented above the diagonal, and for chronically ill participants (n = 189) are presented below the diagonal; all ps < .001. YQOL– R = the Youth Quality of Life Instruments–Research Version; the QOLP–AV = the Quality of Life Profile–Adolescent Version; KIDSCREEN–52 = the Health-Related Questionnaire for Children and Adolescents; QLQ–CA = the Quality of Life Questionnaire for Children and Adolescents.

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B 6 4

6

2

4

0

0

2

Eigenvalue

8

8

10

A

0

5

10

15

Factor

20

25

0

5

10

15

20

25

Factor

FIG. 1. The scree plots for (A) healthy and (B) chronically ill adolescents

RESULTS At the level of general results, all four methods correlated significantly with each other (p < .001; Table 1). The highest correlation in both groups concerned the QOLP–AV and the QLQ–CA, namely .70 for healthy participants and .61 for chronically ill participants (both p < .001), explaining over 36% of common variance. Exploratory Factor Analysis The exploratory factor analysis (principal components with Varimax rotation) extracted four factors – a solution accepted on the basis of the scree test and communalities (Fig. 1). The factors accounted for almost 61% of the total variance. The factors corresponded largely with the content of four instruments used for this study (Table 2). Factor 1.—Developmental quality of life accounted for over 37% of the variance explained, and contained nine variables measured by the scales of the QOLP–AV. All item loadings were above .75. Small variations in the loadings (.76–.84) suggested that the psychological meaning of this factor is very close to the holistic notion of quality of life, focused on wellness and personal development. What makes all the variables measured by the QOLP–AV exhibit such a strong ‘affinity’ is probably the fact that the method takes into consideration the importance and satisfaction scores at the same time, while other questionnaires do not take them into account. The QOLP–AV covers the aspects of the self (from physical characteristics to abilities), the spiritual aspects and the system of values, interpersonal relationships, social milieu and environment, as well as capacities for development. Thus, it treats quality of life as a unity encompassing the basic dimensions of human existence. Factor 2.—Health and Well-being, which accounted for almost 26% of the explained variance, was formed by nine out of ten scales of the KIDSCREEN–52. Loading variation in this case ranged from .50 to .81. According to the loadings, the sense of the factor is determined mostly by

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TABLE 2 FACTOR ANALYSIS FOR DATA OF HEALTHY ADOLESCENTS FROM FOUR QUALITY OF LIFE MEASURES: YQOL–R1, QOLP–AV2, KIDSCREEN–523, AND QLQ–CA4 Factor 3

Factor 4

h2

Social Belonging2

Variable

.84

.10

.18

.16

.77

Spiritual Being2

.82

.09

.19

.07

.72

Growth Becoming2

.81

.17

.16

.19

.74

Psychological Being2

.81

.19

.12

−.00

.70

Physical Belonging2

.80

.13

.14

.01

.68

Practical Becoming2

.80

.17

.14

.17

.72

Community Belonging2

.78

.22

.10

.13

.69

Leisure Becoming2

.77

.18

.10

.01

.63

Physical Being

.76

.24

.09

−.03

.64

Autonomy3

.08

.81

.05

.07

.66

Psychological Well-being3

.15

.74

.41

.07

.75

Social Support & Peers3

.20

.68

.17

−.03

.53

Physical Well-being3

.18

.68

.09

−.08

.51

Parent Relations & Home Life3

.21

.59

.46

.09

.61

Moods & Emotions3

.17

.57

.39

.24

.57

2

Factor 1

Factor 2

Self-perceptions

.21

.55

.35

.10

.47

School Environment3

.30

.52

.24

.18

.45

Financial Resources3

.14

.50

.12

.28

.36

General Quality of Life1

.12

.25

.81

.07

.73

Social Relationships1

.15

.22

.80

.09

.73

Sense of Self1

.17

.25

.80

.13

.75

.18

.26

.70

.13

.60

Life Satisfaction

.20

.39

.52

.47

.68

Skills/Competencies4

.29

.26

.41

.37

.45

3

Environment1 4

Independence4

−.12

−.20

.09

.75

.59

Health-Related Quality of Life4

.15

.14

−.01

.71

.54

Social Integration4

.18

.24

.37

.56

.54

Social Acceptance (Bullying)3

.15

−.06

.30

.36

.24

1.78

1.28

Eigenvalue

10.60

% Variance explained

22.8

3.38 15.7

14.4

7.9

Note.—Factor loadings > .50 are in boldface.

such variables as autonomy, psychological well-being, social support and peers, and physical well-being. Emphasis is, therefore, laid on health as the condition of a broadly conceived activity and agency, which fits the specifics of the health-related quality of life referring to “physical, mental, social, psychological and functional aspects of well-being” (Ravens-

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Sieberer & Bullinger, 1998, p. 399), as seen from the patient's perspective. Hence, quality of life explained by this factor shows an adaptive functioning in all spheres of life of adolescents, with good state of health as a common base. Note, however, that all but one scale of the KIDSCREEN–52 loaded on Factor 2, and only Social Acceptance had a higher loading on Factor 4. A possible explanation is that social acceptance is more a function of extraversion and social skills than health during adolescence. Moreover, the study of the factor structure of health-related quality of life shows the items that form this scale do not become part of any extracted factor (Robitail, et al., 2007). Factor 3.—Relational quality of life accounted for about 24% of explained variance, and it contained four variables measured by the YQOL– R scales, all with high factor loadings (.70–.81), and two other from the QOL-CA with relatively lower loadings (.41–.52). This factor encompasses important aspects of adolescents’ life: the self, a sense of competence, adaptive relations with others, and satisfaction with life. All of them cover satisfaction with oneself, social relationships, and the environment, so they introduce relational quality of life as a whole. Factor 4.—Ego strength accounted for 13% of explained variance. The factor was formed by three scales of the QLQ–CA with high and moderately high factor loadings (.56–.75); one scale from the KIDSCREEN–52, namely Social Acceptance, had a lower loading (.36) in this factor. The highest loadings were for Independence and Health-Related Quality of Life. This factor emphasize autonomy and independence combined with good health, which implies satisfaction with life, contacts with others, and social integration of the person. Due to the fact that confirmatory factor analysis revealed that the four-factor model described above did not fit to the data from chronically ill adolescents (χ2/df = 2.48, RMSEA = 0.089, GFI = 0.741, CFI = 0.825, NFI = 0.74), a second exploratory factor analysis was computed for this group. The factor analysis was carried out in the same way as before. The method of principal components with a Varimax rotation was used, with a set solution intended to isolate four factors (the scree test also suggested that; see Fig. 1). The four factors accounted for almost 59% of the total variance; however, the content of the factors was not entirely convergent with the results of the factor analysis of healthy participants, although it exhibited a number of similarities (Table 3). Principal Components Analysis Factor 1.—Developmental quality of life represented 37% of the explained variance and the result was very similar to that obtained in the analysis of healthy participants. This factor was made up of nine variables investigated by means of the QOLP–AV. As in the former case, loadings

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TABLE 3 RESULTS OF FACTOR ANALYSIS FOR DATA OF CHRONICALLY ILL ADOLESCENTS ON FOUR QUALITY OF LIFE MEASURES: YQOL–R1, QOLP–AV2, KIDSCREEN–523, AND QLQ–CA4 Variable

Factor 1

Social Belonging2

.81

Spiritual Being2 Growth Becoming2

Factor 2

Factor 3

Factor 4

h2

.24

.15

.04

.75

.82

.20

.11

.06

.73

.83

−.07

.23

.08

.76

Psychological Being2

.83

.12

.04

.25

.76

Physical Belonging2

.79

.07

.20

.19

.70

Practical Becoming2

.76

.09

.28

.01

.66

Community Belonging2

.83

.10

.17

.04

.70

Leisure Becoming2

.76

.12

.07

−.05

.60

Physical Being

.63

.09

−.10

.45

.61

Autonomy3

.11

−.05

.59

.36

.49

2

Psychological Well-being3

.18

.15

.55

.59

.70

Social Support & Peers3

.16

.14

.65

.11

.48

Physical Well-being3

.09

−.16

.30

.63

.52

Parent Relations & Home Life3

.30

.28

.53

.13

.47

Moods & Emotions3

.08

.20

.32

.67

.60

−.03

.37

−.06

.60

.49

.13

.11

.65

.12

.49

Self-perceptions

3

School Environment3 Financial Resources3

.10

.35

.50

−.07

.39

General Quality of Life1

.28

.56

.30

.37

.62

Social Relationships1

.18

.73

.38

.19

.74

Sense of Self1

.19

.71

.22

.35

.72

Environment1

.33

.57

.39

.14

.61

Life Satisfaction4

.27

.51

.34

.29

.53

Skills/Competencies4

.09

.32

.58

.00

.45

−.05

.63

.09

−.03

.40

Health-Related Quality of Life4

.15

.21

.00

.60

.42

Social Integration4

.10

.75

.25

−.05

.63

Social Acceptance (Bullying)3

.10

.60

−.08

.23

.43

Independence4

Eigenvalue % Variance explained

9.62 21.9

3.38 14.3

1.83 12.2

1.55 10.2

Note.—Factor loadings > .50 are in boldface.

were moderate to high (.63–.83). The psychological sense of this factor covers the developmental, dynamic aspect of quality of life in adolescents: self-reference, connections with others, a sense of belonging to a group or community, and development in all these spheres. The participants were chronically ill; hence, the assessment of significance and satisfaction in the

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area of practical skills, coping, and development capacities is extremely important. Factor 2.—Harmony between the self and the environment accounted for over 24% of the explained variance, and consisted of four variables originated from the YQOL–R, three variables from the QLQ–CA, and one from the KIDSCREEN–52. The loadings were between .56 and .75. Psychological meaning of the factor is determined by social relationships and integration as well as a sense of self and independence, accompanied by relationship to the environment, social acceptance, and general quality of life. This factor comprises all variables measured by the YQOL–R as well as by some other scales that describe contact with social environment, independence, and satisfaction with life. The factor includes positive selfimage, satisfactory relationships with others, and self-reliance. Containing a sense of self and a broad area of social relationships, the factor accurately reflects the needs of adolescents who are ill. Factor 3.—Coping and Support accounted for about 21% of explained variance and contained six or seven variables, six from the KIDSCREEN–52: Social Support and Peers, School Environment, Autonomy, Parent Relations and Home Life, Psychological Well-being, and Financial Resources; and one from the QLQ–CA - Skills/Competencies. Loadings were strong (.50–.65). This factor covers the skills and competencies necessary for adaptive functioning at school and in the environment, but also certain objective elements like financial resources and other possibilities satisfying personal needs and promoting a good position within a peer group. Factor 4.—Health-related quality of life accounted for over 17% of the explained variance and was composed of the following five scales: Moods and Emotions, Physical Well-being, Self-perception, Psychological Wellbeing from the KIDSCREEN–52, and the Health-Related Quality of Life from the QLQ–CA. All five variables are related to health problems, directly or indirectly. They cover both physical complaints and a frame of mind, and comprise the spheres of life where the question of health manifests itself especially clearly and in a particularly noticeable way during adolescence. Procrustes Rotation To compare the two factor structures, the Procrustes rotation was used, and Tucker's coefficients of congruence were applied to collate particular factors (Table 4). The correlation in a symmetric Procrustes rotation was .79 (p < .001), which shows significant affinity between two factor structures regardless of particular differences, seen especially when the pairs of factors are compared. In Factor 1, Developmental quality of life for both groups was nearly the same, and the coefficient of congruence was excellent. There was also

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FACTOR STRUCTURE: QOL TABLE 4 TUCKER'S COEFFICIENTS OF CONGRUENCE Healthy Group

Chronically Ill Group Factor 1

Factor 2

Factor 3

Factor 4

Factor 1

.98

.36

.45

.40

Factor 2

.44

.47

.87

.75

Factor 3

.46

.87

.70

.60

Factor 4

.30

.73

.45

.38

Note.—Factor loadings > .85 are in boldface. Factors for the healthy group: 1. Developmental quality of life, 2. Health and Well-being, 3. Relational quality of life, 4. Ego strength; and for patients with chronic illnesses: 1. Developmental quality of life, 2. Harmony between the self and the environment, 3. Coping and Support, and 4. Health-related quality of life.

affinity between Factor 3, Relational quality of life, in the healthy group and Factor 2, Harmony between the self and the environment in chronically ill patients, as well as between Factor 2, Health and Well-being, in the healthy group and Factor 3, Coping and Support, in patients with chronic illnesses; both coefficients of congruence were fair. Thus, Factors 1 through 3 were well reproduced across the samples. However, Factor 4, Ego strength, in the healthy group was not well reproduced in the group of chronically ill patients. Altogether, both sets of factors have a clear correspondence concerning Factors 1 through 3, and a clear difference concerning Factor 4. DISCUSSION The factor structure of quality of life in adolescents extracted in this study consists of four dimensions; between the two groups (healthy and ill adolescents), the structure differs somewhat. This structure shows only a slight affinity to the one suggested by the definition of quality of life. According to the theory-driven approach, the general dimensions should include: physical health, psychological state, independence, social relationship, and relation to environment. According to the empirically-driven approach, the dimensions are different, so Hypothesis 1 was not supported. Moreover, the factor structures obtained in the healthy group and in the chronic patients' group are to some extent similar (Factors 1 through 3) and to some extent different (Factor 4), so Hypothesis 2 was supported. The results are challenging to explain, because the obtained factor structure corresponds very feebly with the dimensions pointed out in the definition of quality of life (WHOQOL Group, 1995). The first factor analysis, based on the results obtained from healthy participants, sorts out the variables largely in accordance with the content of the methods employed. This can be treated as empirical evidence that the scales measure

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different aspects of perceived quality of life, despite significant correlations among the general scores (from .36 to .70). At the same time, similarities and differences in the factor structures for healthy and ill adolescents refer to common and group-specific elements. The four-factor solution could reflect, in part, that the items in the various instruments had different formats and different response scales (from 3- to 11-point scales). However, apart from possible influence of the differences among the instruments on the results of factor analysis, such differences can influence but do not determine the results in analyses based on correlations, e.g., factor analysis. Moreover, if the format and/or the response scale matter, the similarities between factor structures for healthy and ill adolescents would be more spectacular. This was not the case. Somewhat different factor structures in the two groups probably mirror the different psychological situations of healthy and ill adolescents (Petersen-Ewert, et al., 2011). Moreover, the group of chronically ill adolescents comprised participants who were ill with several different illnesses. This could have been responsible for the greater variances in this group, thereby increasing differences in factor structures between the two groups. For example, social relationships in the most healthy adolescents are not disturbed so the satisfaction of them is relatively high, while in the case of chronically ill adolescents social relationships play many roles, including social support, and could vary among the participants more markedly. What is, therefore, the specific nature of quality of life? Factor 1, Developmental quality of life, covers the developmental aspect of the perceived quality of life, combining the assessment of importance and satisfaction with the possibilities of development in particular spheres measured by the QOLP–AV method. Factor 2, Health and Well-being, covers health conditions for the optimum functioning, investigated by means of the KIDSCREEN–52. Factor 3, Relational quality of life, contains the relational aspect of the quality of life, which is investigated mainly by means of the YQOL-R measure. Factor 4, Ego strength, pertains to general satisfaction with life, measured mainly with the QLQ–CA. Despite the fact that the factor structure obtained from healthy participants corresponds with the structure of the measures, the factor structure obtained from chronically ill participants was to some extent different and to some extent similar. An almost ideal similarity applies only to the first factor, Developmental quality of life. The interpretation of life quality called here “developmental” refers to the humanistic-existential tradition describing a person in terms of physical, mental, social, and spiritual dimensions. It emphasizes basic human needs; e.g., the need to belong and to strive to implement one's goals, to make choices, and to make decisions are the conditions of optimal development (Renwick & Brown, 1996; Shel-

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don, 2004). The similarity between the first factors in two studies (Tucker's coefficient of congruence was very high at .98) emphasizes that full development of an individual, understood as an active agent, is crucial in adolescence regardless of the state of health of a person (Renwick & Brown, 1996). The basic elements that constitute quality of life are the same for all adolescents. The differences, in turn, arise from the areas of life that are important to the individual, and from the extent individuals derive satisfaction from important possibilities that life offers (Raeburn & Rootman, 1996). Interestingly enough, the structures of quality of life in healthy people and people with disabilities were the same, except significant differences in factor loadings for the two groups (Horner-Johnson, Suzuki, Krahn, Andresen, Drum, & The RRTC Expert Panel on Health Measurement, 2010). In addition, the similarity between Factor 2, Health and Well-being for healthy participants, and Factor 3, Coping and Support (and to some extent the Factor 4, Health-related quality of life) for participants who were ill, cannot be ignored although the content of factors according to the loadings is somewhat different. For healthy adolescents, the factor suggests conditions of life satisfaction that are associated with a good physical condition; for adolescents who are ill, the factor suggests some healthrelated conditions influence their well-being and activity. The elements in common pertain to physical and mental state, mood and emotions, and self-perception. Health as physical and mental well-being is an important component of quality of life, both for the healthy and the sick (Raeburn & Rootman, 1996). When assessing the quality of life of adolescents who are ill, the aspects of illness and its effects are sometimes belittled. In this age group, it may result from a strong desire to be like their healthy peers (Räty, Larsson, & Söderfeldt, 2003). There is also a relationship between Factor 3, Relational quality of life, which covers the relationally described quality of life (YQOL–R) for healthy participants, and Factor 2, Harmony between the self and the environment, for the participants who were ill. Both of them pertain to the relations between a person and the environment, although the factor for adolescents who were ill has a broader scope. Both factors emphasize activity in the environment, independence, and integration with a group. The differences between the healthy and the ill apply to the aspects important for adolescents regardless of health or illness; for instance, striving for autonomy and independence (Harter, 1999; Steinberg, 2008). However, ill adolescents can experience stronger pressure from their environment; for example, parental care and protectiveness, and support and concern. Such attitudes may result in difficulties in achieving full independence and selfreliance. Integration and belonging to a group can, in turn, be significantly restricted by illness.

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Factor 4, Ego strength, for healthy participants, did not have any obvious equivalent in the group of participants who were ill. The comparison of factor structures of quality of life suggests that a chronic illness indirectly modifies the structure of chronically ill participants, despite the similarity in developmental facets of quality of life expressed by the first factor, Developmental quality of life. The content and psychological sense of the other factors is somewhat different. The difference in factor structure and greater interweaving of scales in particular factors suggest that a state of health (illness) has modifying effect on perceived quality of life in adolescents. However, the similarity of the first factors suggests that the quality of life construct can (to a certain extent) be applied, by analogy, to healthy persons and those who are ill. This is a legitimate assertion because both ill and healthy adolescents have the same needs and are subject to the same developmental needs. Adolescents who are ill face specific challenges associated with illness, treatment, and all kinds of limitations (Taylor, Gibson, & Franck, 2008). Their functioning includes coping with illness, which is why they may have greater difficulties in achieving their goals. They often need special support which in turn Factor 3, Coping and Support, seems to render. Generally speaking, analyses that tend to reveal the structure of variables and measures, as this study does, can show their empirical order, their specific nature, and overlapping (Goldbeck & Schmitz, 2001; Robitail, et al., 2007). A question about the possible integration of the four concepts of quality of life (relevant for this study) resulted in a complex model (Fig. 2). Taking into account the universal needs in adolescence, the most important seems to be a developmental dimension of quality of life; this factor explained over one-third of variance (37%) and was replicated in both groups (usually measured by the QOLP–AV). Also relevant, although rather weak, is the general quality of life (QLQ–CA). Two other dimensions are interacHealth-related quality of life (KIDSCREEN)

Developmental quality of life (QOLP-AV)

Interactive quality of life (YQOL-R)

General quality of life (QLQ-CA)

FIG. 2. Complex model of quality of life in adolescence

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tive (YQOL) and health-related quality of life (KIDSCREEN was the instrument applicable for healthy as well as ill adolescents). The former emphasizes the fact that quality of life is always rooted in the person–environment relation, while the latter emphasizes particular aspects necessary for assessment of health as an important condition of quality of life in adolescents. Illness modifies experiences due to limitations and treatment, and, even more importantly, influences the subjective perception of life priorities, goals, social relations, and self-esteem. Chronic illness, as one of the most stressful events of one's life, can promote defense but also stimulate personal maturity. Thus, the individual perspective of quality of life and its assessment seems to be different in ill and healthy people, especially during late childhood and adolescence when basic schemata of interpretation of oneself, others, and the world are being shaped (De Civita, Regier, Alamgir, Anis, Fitzgerald, & Marra, 2005; Ravens-Sieberer, et al., 2006). What are the limitations of this study? Firstly, this study concerns selfrated quality of life, and was not externally evaluated. Secondly, the samples were not representative, being rather incidental than random. The research conducted in Poland must be replicated in other countries before plausible generalization can be made. Thirdly, the group of participants with chronic illnesses was heterogeneous, in that the adolescents suffered from a range of illnesses. This fact could influence the factor structure (perhaps more so than if all adolescents suffered from the same illness) making it less similar to the one extracted for healthy adolescents. Fourthly, one should be aware that in using the principal component analysis to identify latent factorial structure of the observed variables, the researcher decides about the number of factors (e.g., according to a scree test) as well as the loadings used for factor description, which markedly influences the factorial model (Coste, Bouée, Ecosse, Leplège, & Pouchot, 2005). Finally, the empirical approach tending to identify main components of quality in children and adolescents is an alternative, or in the best case complementary, to theory-driven and clinical approaches (Petersson, Simeonsson, Enskar, & Huus, 2013). Quality of life in adolescents, as in adults, is a complex construct, implying a need for multidimensional assessment (Goldbeck & Schmitz, 2001). The choice of any method leads to the investigation of quality of life from a specific angle. The results of this study may suggest that in order to understand subjective quality of life in a comprehensive and multi-faced extent, several measurement methods are required. Such an investigation would be time-consuming and not economical, although it would be more complete and detailed. The structure of subjective quality of life emerging from this study (see Fig. 2) has another practical implication. Namely, for preliminary or screening assessment of quality of life in adolescents, one can recommend Schalock's approach and method (QLQ–CA). For assess-

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ing quality of life from the perspective of its developmental dynamic as well as possible inspirations and inhibitions present in the social and environmental context, the best instrument seems to be “3B”: Being, Belonging, and Becoming (QOLP–AV). When one focuses on the social aspect of the quality of life, especially on the role of interaction between a person and social environment in the process of shaping identity during adolescence, the model and approach proposed by Patrick, et al. (2002) seem adequate (as does the YQOL). Finally, in every problem when a state of health can influence quality of life in both a positive and a negative way (to recover, or to decline), use of the KIDSCREEN is advised. This method allows the assessment of quality of life as a state, so it is recommended especially for follow-up or longitudinal studies. To conclude, the assessment of quality of life in adolescents should be based on a choice of proper instruments according to a relevant aspect in a given case. Another solution is to develop a new universal measure using the results of this study pointing out the four-dimension structure of quality of life as an inspiration. Nevertheless, such a structure requires confirmation in further research. REFERENCES

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