Predictors of Health-Related Quality of Life in Obese Youth

Authors

  • Meg H. Zeller,

    1. Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio.
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  • Avani C. Modi

    Corresponding author
    1. Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio.
      Division of Behavioral Medicine and Clinical Psychology, MLC-3015, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229. E-mail:meg.zeller@cchmc.org
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  • The costs of publication of this article were defrayed, in part, by the payment of page charges. This article must, therefore, be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Division of Behavioral Medicine and Clinical Psychology, MLC-3015, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229. E-mail:meg.zeller@cchmc.org

Abstract

Objective: Recent literature has documented the psychosocial consequences of pediatric obesity, including poor health-related quality of life (HRQOL). The present study examines HRQOL and its association with depressive symptoms and perceived social support in African-American and white youth pursuing weight management treatment.

Research Methods and Procedures: Study participants were 166 obese youth (mean = 12.7 years, 70% females, 57% African American, mean BMI = 37.0) referred to a pediatric weight management program. Parents of participants completed a demographics form and the parent-proxy Pediatric Quality of Life Inventory (PedsQL). Youth completed the Children's Depression Inventory, PedsQL, and Perceived Social Support Scale for Children.

Results: HRQOL scores were quite impaired relative to published norms on healthy youth (p < 0.001). Approximately 11% of the sample met criteria for clinically significant depressive symptoms. Simultaneous regression analyses revealed that depressive symptoms, perceived social support from classmates, degree of overweight, and socioeconomic status seem to be strong predictors of HRQOL.

Discussion: Obesity has a clear impact on HRQOL regardless of respondent (e.g., parent, youth) or racial group. It is likely that assessing and treating depressive symptoms and fostering social support in the context of pediatric intervention have implications for both improved HRQOL and weight management outcomes.

Introduction

The prevalence of pediatric obesity has increased dramatically in the past 3 decades, with current estimates indicating that ∼15.5% of children and adolescents are obese (1). This substantial increase is not uniform across sex or race, with rates of obesity being highest in African-American female adolescents (1,2). There is growing literature documenting the health consequences of obesity (3,4,5); however, the greater immediate costs of pediatric obesity may be psychosocial. There is considerable risk of continued and mounting psychosocial impairment and poor developmental adaptation for obese youth (6,7,8,9), suggesting a need for early weight management intervention that is tailored to address supports and barriers within the child's or adolescent's environment.

The measurement of health-related quality of life (HRQOL)1 is one method used to assess global psychosocial functioning. HRQOL is a multidimensional construct with several core dimensions, including physical, emotional, and social functioning (10). HRQOL reflects the individual's subjective evaluation of his/her own well-being and functioning (11). The measurement of HRQOL in children and adolescents across pediatric disease groups has grown tremendously in the past decade (12). Following this trend, there is now an early literature documenting a strong and consistent relationship between impaired HRQOL and obesity in children and adolescents.

Three recent studies have used the Pediatric Quality of Life Inventory (PedsQL) (13) to assess self-report and parent-proxy report of HRQOL in obese youth. Schwimmer et al. (14) reported that obese children and adolescents pursuing weight management treatment reported poorer HRQOL across all domains of functioning (physical, emotional, social, and school) compared with instrument norms of healthy youth and similar scores compared with youth diagnosed with cancer. Similarly, two recent studies reported an association between impaired HRQOL and obesity in a population-based study of Australian children (15) and a clinical sample of obese youth with sleep-disordered breathing (16). Additional studies, using the KINDL (17) and Child Health Questionnaire (18), have documented poor HRQOL in obese children using both self-report (19) and parent-proxy measures (20,21). Taken together, these data begin to document the significant impact of overweight and obesity on child and adolescent HRQOL. A logical next step to advance the literature is to examine the level of agreement between parents and children regarding the child's HRQOL and the predictors of better or worse HRQOL in obese youth. These data will inform both the measurement of HRQOL and key targets for intervention for obese youth.

Poor HRQOL has been associated with higher rates of depressive symptoms in otherwise physically healthy youth (22) and in youth with chronic medical conditions such as asthma (22) and cardiac disease (23). However, no study, to date, has examined this important relationship in a sample of obese youth. There is a solid literature documenting that some obese youth who seek weight management treatment present with depressive and/or internalizing symptoms (24,25,26,27,28,29,30,31). For example, our recent data from a sample of treatment-seeking obese white and African-American youth found rates of mother-reported depressive symptoms significantly greater than population base rates (32). However, studies from community samples reveal variable rates of depressive symptoms (33,34,35). Combined, these data suggest the need to further investigate depressive symptoms in the context of the obese child's and/or adolescent's day-to-day functioning.

The adult behavioral medicine literature has reported strong links between perceived social support and HRQOL (36,37), suggesting that perceived social support may have health-protective effects (38). Specifically, perceived social support is a cognitive appraisal regarding the availability of significant others in the individuals’ social network, the care provided by network members, and how satisfied and valued they are within these relationships. Within the context of normal child development, it is asserted that different sources of support (e.g., friends, parents, classmates) may play unique roles and vary in perceived importance at different points in development (39,40). Furthermore, perceived social support has been found to differentially affect psychological adjustment in healthy youth (41,42) and in children with chronic medical conditions (43,44,45). A critical gap in the pediatric obesity literature is how perceived social support from the social network of obese youth is associated with their daily functioning and depressive symptoms.

The aims of the current study were to: 1) document the HRQOL, depressive symptoms, and perceived social support in a diverse, clinically referred sample of obese children and adolescents; 2) examine the degree of agreement between youth and parents regarding HRQOL; and 3) identify predictors of better HRQOL (i.e., physical, emotional, social, school) in obese youth. It was hypothesized that obese youth and their parents would report more impairment in HRQOL compared with instrument norms. Children and parents were expected to have lower agreement on emotional HRQOL and higher agreement on physical HRQOL. It was hypothesized that a small proportion of obese youth would report depressive symptoms within a clinical range. It was also hypothesized that obese youth would report lower perceived social support from classmates and teachers compared with parents and friends. Finally, demographic characteristics, degree of obesity, sources of perceived social support, and depressive symptoms would be utilized as predictors of HRQOL domains. Given similar item content, it was expected that specific scales (e.g., depressive symptoms score, peer-based social support) would be strong predictors of similar HRQOL domains (e.g., emotional, social). However, it was hypothesized that depressive symptoms and sources of social support would be strong predictors of all domains of HRQOL.

Research Methods and Procedures

Participants and Procedures

Study participants included 166 obese children and their parents seeking treatment through a hospital-based pediatric weight management program. This program requires a BMI ≥ 95th percentile and excludes youth with genetic syndromes associated with obesity and developmental disabilities. Eligibility criteria for the current study included: being 8 to 18 years of age, parental endorsement of child's independent reading ability, and willingness to comply with study procedures and provide written informed consent/assent.

All participants who attended a prescreening visit between August 2003 and May 2005 received information letters and brochures describing the study about HRQOL in youth presenting for weight management. These participants were subsequently approached for recruitment and participation during this medical screening visit at the General Clinical Research Center (GCRC) at Cincinnati Children's Hospital Medical Center (CCHMC). Of the 192 potential participants, 26 eligible participants were not included for the following reasons: 16 parents declined to participate, seven participants were one of two siblings, and three participants had difficulty understanding the questionnaires due to inattention or reading difficulties. A summary of demographic characteristics of participants is presented in Table 1.

Table 1. . Demographic information of obese youth (n = 166)
 NMean (SD)%
  • *

    Based upon Duncan TSEI2 for head of household, a measure of occupational attainment. Scores range from 15 to 97, with higher scores representing greater occupational attainment. The mean TSEI2 score reflects occupations such as clerks, typists, and machine operators.

Age 12.7 (2.4) 
Sex   
  Girls117 70
  Boys49 30
Race   
  White67 40
  African American94 57
  Bi-racial/other3 2
  Hispanic2 1
Anthropometric data   
  BMI 37.0 (7.2) 
  zBMI 2.5 (0.28) 
Participating caregiver   
  Mother146 88
  Father8 5
  Grandmother8 5
  Other4 2
Marital status   
  Married64 39
  Separated/divorced39 24
  Single/never married55 33
  Widowed8 5
Duncan score* 34.2 (17.9) 

All personnel were trained to recruit and screen participants, administer consent forms, and instruct or administer questionnaires to both children and their parents. Parents of participants were asked to complete a demographics form and the parent-proxy PedsQL. Participants were asked to complete a series of questionnaires including the Children's Depression Inventory (CDI), PedsQL, and Perceived Social Support Scale for Children (SSSC). Instructions for each measure were read to each child; however, in general, the measures were each completed individually. The child's weight and height were also obtained. Participants were compensated for participating in the study with a $10 gift certificate to a local department store. The protocol was approved by the CCHMC Institutional Review Board.

Measures

Demographic Background Questionnaire

Parents completed a background questionnaire to provide information including race, marital status, and parent occupation. Adequate data were available to calculate the Revised Duncan (TSEI2) (46) for each family, an occupation-based measure of socioeconomic status (SES) (47). This occupational-based measure is a contemporary indicator of SES (48). Scores range from 15 to 97, with higher scores representing greater occupational attainment. For two-caregiver households, the higher Duncan score was used in analyses.

PedsQL

The PedsQL is a generic HRQOL measure developed for children and adolescents, as well as a parent-proxy version (13). The measure consists of four generic core scales, including physical (eight items), emotional (five items), social (five items), and school functioning (four items), as well as two broad domain scores (physical and psychosocial functioning) and a total score. Scales are standardized, and scores range from 0 to 100, with higher scores representing better quality of life. The PedsQL has been shown to be both reliable and valid, with internal consistency reliability coefficients approaching or exceeding 0.70.

CDI

The CDI is a 27-item self-report measure developed to assess depressive symptoms in children and adolescents. This is the most widely used measure of depression in children. Extensive data have supported its reliability and validity (49,50), including for African-American youth (51,52). For the present analyses, the total raw score was utilized, with higher scores reflecting more depressive symptoms. A total raw score ≥ 20, which is considered a conservative estimate, indicates depressive symptoms in the clinical range (49).

Perceived SSSC

The SSSC (53) is a 24-item measure designed to assess the perceived support and regard that children receive from significant others, including parents, teachers, classmates, and close friends. The measure asks children and adolescents how much significant others like and value them as a person, understand them, and make them feel cared for and heard. The structured alternative format is utilized to prevent socially desirable responding. The SSSC scores have been shown to have good internal consistency (αs range from 0.72 to 0.88). A total score, as well as scores for the different sources of support, was calculated.

Weight and Height

GCRC nurses trained in methods of obtaining accurate anthropometric measures obtained height and weight from child participants. Weight was measured (0.1 kg) on a digital Scaletronix scale (Wheaton, IL). Standing height was measured with a Holtain stadiometer (Holtain, Crymych, United Kingdom). Participants were weighed and measured in street clothing without shoes. These data were used to calculate BMI (kilograms per meter squared) and the standardized BMI (zBMI) using age- (to the nearest month) and sex-specific median, standard deviation (SD), and power of the Box-Cox transformation (least-mean-square method) based on national norms from the Centers for Disease Control (54). Details regarding the calculation of zBMI using the least-mean-square method are available at www.cdc.govnchsaboutmajornhanesgrowthchartsdatafiles.htm.

Statistical and Data Analyses

Descriptive analyses, including means and SDs, were calculated for self-reported and parent-proxy HRQOL, depressive symptomatology, and perceived social support scales. z Tests were conducted to compare HRQOL scores between the instrument normative data of a healthy sample and youth with obesity. Intraclass correlations and paired Student's t tests were used to determine the convergence of parent and child report of HRQOL. An intraclass correlation of ≥0.75 suggests high agreement (55). Paired Student's t tests were conducted to examine differences in sources of perceived social support. Based on Bonferroni correction, p values were set at 0.008 to achieve significance (0.05/6 = 0.008). Pearson correlation coefficients were calculated to examine relationships among total HRQOL, depressive symptoms, and total perceived social support. Analyses were performed using statistical software (SPSS version 11.5; SPSS Inc., Chicago, IL).

Finally, we were interested in examining the predictors of multiple domains of HRQOL. Due to the high probability that these domains would be intercorrelated, separate models for each domain of functioning would be misleading. Path analysis is one statistical methodology that can be used in cases where multiple correlated dependent variables are modeled in a system with the same independent variables as predictors (56). Multivariate simultaneous multiple regression analyses using path analysis, using Lisrel 8.54 (Scientific Software International, Inc., Lincolnwood, IL), were conducted to predict domains of HRQOL (e.g., physical, emotional, social, and school). Dependent variables were allowed to freely correlate in the model. Independent predictors included demographic variables (i.e., race, sex, age, and SES), zBMI, sources of perceived social support (i.e., parent, classroom, teacher, and friend), and total depressive symptoms. Significance was identified as p < 0.05 unless otherwise noted.

Results

HRQOL between Obese and Healthy Youth

Both parent-proxy and self-reported HRQOL scores for youth with obesity were quite impaired relative to published norms on healthy youth (see Table 2). For example, the mean score for total self-reported HRQOL was 68.9 for obese youth compared with 83.0 for healthy children.

Table 2. . Generic HRQOL scale for obese and healthy youth
 Obese sample (n = 166)Healthy sample*
PedsQLMeanSDMeanSDdfz
  • SD, standard deviation; df, degrees of freedom.

  • *

    Adapted from published data on norms for healthy children (13).

  • All values are significant, p < 0.001.

Youth self-report      
 Physical functioning71.117.584.417.3565−8.3
 Emotional functioning66.421.180.919.6565−7.6
 Social functioning69.726.087.417.2564−8.1
 School functioning67.120.478.620.5551−6.1
 Psychosocial functioning67.818.082.415.5564−9.1
 Total score68.916.283.014.8566−9.7
Parent-proxy report      
 Physical functioning58.820.489.116.0554−17.0
 Emotional functioning59.720.382.218.4553−12.3
 Social functioning58.620.992.513.1553−19.4
 School functioning64.320.785.517.0542−11.6
 Psychosocial functioning60.917.186.712.9553−17.4
 Total score60.316.687.612.1553−19.1

Parent-Child Convergence on HRQOL

Poor agreement was found for self-reported and parent-proxy physical functioning (r1 = 0.08, p = 0.14), emotional functioning (r1 = 0.28, p < 0.001), social functioning (r1 = 0.33, p < 0.0001), school functioning (r1 = 0.40, p < 0.0001), total psychosocial functioning (r1 = 0.33, p < 0.0001), and total HRQOL (r1 = 0.28, p < 0.001). Parents reported significantly lower HRQOL than their children on most scales: physical [t (164) = 6.6, p < 0.0001], emotion [t (163) = 3.5, p < 0.001], social [t (164) = 5.5, p < 0.0001], psychosocial [t (163) = 4.5, p < 0.0001], and total HRQOL [t (163) = 5.9, p < 0.0001].

Depressive Symptoms in Obese Youth

The mean total raw score of depressive symptoms for the total sample was in the non-clinical or normal range (mean = 9.5, SD = 6.7). Approximately 11% of the total sample met the criteria for clinically significant depressive symptoms based on the most conservative criteria (raw scores ≥ 20). However, using a less conservative criterion recommended for clinical settings (raw scores ≥ 12) (49), ∼34% of youth exhibited significant depressive symptoms.

Sources of and Levels of Perceived Social Support

Parents provided significantly higher levels of perceived social support compared with classmates [t (165) = 7.1; p < 0.0001] and teachers [t (165) = 4.3; p < 0.0001]. Friends also provided significantly higher levels of perceived social support compared with classmates [t (164) = −7.5; p < 0.0001]. No significant differences were found between perceived social support provided by friends and that provided by teachers or parents.

Intercorrelations of HRQOL, Depressive Symptoms, and Perceived Social Support

A strong negative correlation was observed between total HRQOL and depressive symptoms (r = −0.68; p < 0.0001), suggesting that obese youth with increased depressive symptoms are more likely to have lower total HRQOL. In addition, higher levels of perceived social support were related to better total HRQOL (r = 0.45; p < 0.0001). A significant negative correlation was also found between depressive symptoms and perceived social support (r = −0.45; p < 0.0001), indicating that obese youth with higher depressive symptoms were more likely to report lower levels of perceived social support.

Prediction of HRQOL

Simultaneous regression analyses were conducted to examine the independent contributions of child age, zBMI, gender, race, SES, sources of social support (i.e., parent, classroom, teacher, friend), and depressive symptoms on four domains of HRQOL (i.e., physical, emotional, social, school). Significant predictors of positive physical HRQOL included lower zBMI, male gender, lower depressive symptoms, and higher classroom social support [R2 = 0.34, adjusted R2 = 0.29, F (4, 149) = 7.6, p < 0.001]. Significant predictors of positive emotional HRQOL included older age and lower depressive symptoms [R2 = 0.42, adjusted R2 = 0.38, F (4, 149) = 10.8, p < 0.001]. Significant predictors of positive social HRQOL included lower zBMI, higher SES, lower depressive symptoms, and higher classroom social support [R2 = 0.53, adjusted R2 = 0.50, F (4, 149) = 17.1, p < 0.001]. Significant predictors of positive school HRQOL included higher SES and lower depressive symptoms [R2 = 0.32, adjusted R2 = 0.27, F (4, 149) = 6.9, p < 0.001] (See Figure 1).

Figure 1.

Path analysis of simultaneous regressions predicting domains of youth self-report of HRQOL. For ease of interpretation, arrows and standardized β weights are presented for significant relationships. Significance defined as * p < 0.05 and ** p < 0.01.

Discussion

Children and adolescents with obesity demonstrated significant impairments in HRQOL compared with a healthy sample based on instrument norms. Poor quality of life was demonstrated in all domains of functioning, suggesting that the day-to-day life of obese youth is globally impacted by this condition. These data are consistent with previous studies suggesting that obese youth, from the community and those who are treatment-seeking, report poor HRQOL (14,15). Our data further document a lack of race effects when examining HRQOL in obese treatment-seeking youth (14).

HRQOL impairments were reported by both youth and parents, suggesting agreement about the types of difficulties obese youth experience in their daily functioning. However, our analyses revealed that parents reported significantly more impairment for a majority of HRQOL domains as compared with their children. For example, parents viewed their children as having greater impairments in emotional and social functioning than the youth reported themselves. These findings of lower agreement for internal domains (e.g., emotion) between children and their parents are not unique to obesity because they are consistent with findings regarding HRQOL in other pediatric populations (57,58). Another possible reason for lower parent-child agreement in these specific domains may be the impact of parental functioning. For example, mothers of treatment-seeking obese youth report significant levels of maternal distress (31,32), which is likely to negatively influence parent-proxy reports of their child's emotional functioning (59). Based on research conducted by Verrips et al. (58), the lack of parent-child convergence for physical HRQOL was unexpected. It is unclear why obese children and their parents disagree about this more observable domain of functioning. With parents reporting much lower levels of functioning, the child's viewpoint of HRQOL is important and allows healthcare professionals to tailor both medical and psychosocial treatment to their particular needs (60). However, the parent's viewpoint is critical given that they play a key role in the treatment initiation process (61,62). Thus, obtaining both the child and parent perspectives regarding HRQOL in obese youth is currently recommended and is particularly warranted for younger children (63).

Only 11% of our sample reported depressive symptoms in the clinical range based on a conservative criterion, which is consistent with a 10% prevalence rate of depressive symptoms in a community sample (64). Recognizing that this is not a formal psychiatric diagnosis and merely an endorsement of symptoms, these data suggest that only some obese youth who seek weight management treatment are experiencing clinically elevated internalizing symptoms (42). However, depressive symptomatology has the most significant impact on all domains of HRQOL for obese youth. It is known that depressive symptoms play a role in poorer obesity treatment outcomes in youth. For example, depressive symptoms have been associated with poor adherence to a weight management intervention for African-American adolescent females (65) and a predictor of attrition from a pediatric weight management program for both African-American and white youth (32). It is likely that assessing and treating depressive symptoms in the context of pediatric intervention has implications for both improved HRQOL and weight management outcomes.

Consistent with the broader developmental literature (39,40), obese youth reported higher levels of perceived social support from parents and friends compared with their teachers and classmates. Several researchers have utilized parents and peers in the design of weight management programs for youth. For example, targeting both a parent and the identified youth in treatment has been implicated in better weight loss outcomes for adolescent African-American girls (66) and white samples of youth 8 to 12 years old (67). Incorporating peer social support has also proven beneficial for weight loss and its maintenance for both adolescents (68) and adults (69). However, studies have not assessed the mechanisms by which these sources of social support serve as a protective health factor beyond their joint participation in intervention efforts.

The current study elucidates robust relations among impaired HRQOL, depressive symptoms, lower perceived social support, and degree of overweight. As expected, and consistent with Schwimmer et al. (14), a higher degree of overweight was associated with lower physical and social HRQOL. Thus, a child or adolescent whose weight gain progresses to the level of extreme obesity is more likely to report impaired physical functioning and greater peer-based difficulties. However, the strongest predictors of HRQOL for obese youth were depressive symptoms and perceived social support from classmates. Thus, obese youth who feel supported by their school-based peer group and who are less depressed may have better HRQOL, specifically as it relates to physical and social functioning. Perceived classmate social support has been reported as an important predictor of psychological adjustment of youth with chronic medical conditions such as cancer (43), limb deficiencies (44), and rheumatic diseases (45). It is known that obese youth experience a peer environment in which they are subject to more name calling and teasing about their appearance (70,71,72), are more victimized by peers (73), and are more socially marginalized than youth of average weight (74). These psychosocial consequences have a significant impact on the daily functioning of youth with obesity. Overall, these data suggest that targeting classmate support may be critical in buffering obese youth from significant HRQOL impairments. Furthermore, these data highlight the importance of developing interventions that not only use parents and friends but also address the lack of perceived social support provided by classmates. Interventions that aim to modify the broader school environment by promoting healthful eating and physical activity behaviors for all youth may, thus, have positive health and HRQOL outcomes.

This study represents the first look, to our knowledge, at the relations among HRQOL, depressive symptoms, and perceived social support in obese youth; however, several limitations were noted with consequent directions for future research. The current study utilized a selective sample of treatment-seeking obese youth and their families. These families were motivated to receive weight management intervention, possibly due to psychosocial distress and encouragement within the social network. Therefore, the treatment implications derived from study results are most salient to this particular population. Future research should examine these same relationships within non-treatment-seeking obese youth.

The restricted range of weight status (all had BMIs ≥ 95th percentile) in the present study limits a full exploration of differences in psychosocial functioning and perceived social support by degrees of overweight. For example, it is possible that the relationship between child/adolescent HRQOL and degree of overweight may not be consistently linear, or a child/adolescent's weight may need to achieve a particular threshold for HRQOL impairments to develop. The present data and those of Williams et al. (15) have begun to address this empirically and suggest that weight-related differences are likely.

Finally, as with other illness populations (75), obesity researchers have begun the development and validation of obesity-specific HRQOL measures. Disease-specific instruments target domains and symptoms most relevant to a particular disease. They are typically more sensitive than generic instruments to changes in quality of life that result from treatment (76) and may reduce the noise of medical comorbidities (77). Future research will need to examine differences in the sensitivity of the PedsQL, a generic measure, as compared with the Impact of Weight on Quality of Life-Kids, disease-specific measure for adolescents (78).

Acknowledgement

This work was supported by NIH (Grant K23 DK60031 to M.H.Z. and Postdoctoral Training Grant T32 DK063929 to A.C.M.). Additional resources were provided by CCHMC-GCRC, which is supported, in part, by United States Public Health Service Grant M01 RR 08084 from the GCRC Program, National Center for Research Resources/NIH.

Footnotes

  • 1

    Nonstandard abbreviations: HRQOL, health-related quality of life; PedsQL, Pediatric Quality of Life Inventory; GCRC, General Clinical Research Center; CCHMC, Cincinnati Children's Hospital Medical Center; CDI, Children's Depression Inventory Children's Depression Inventory; TSE12, Revised Duncan; SES, socioeconomic status; SSSC, Social Support Scale for Children; zBMI, standardized BMI; SD, standard deviation.

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