Copyright 2003 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.2003
To examine the association between health-related quality of life and body mass index (BMI) in preadolescent school-aged children and to provide the possible risk factors among participant characteristics, BMI status, and health-related quality of life.
Design, Setting, and Participants
Cross-sectional analysis of 371 (50% female; 32% minority) children from a community-based sample of 8- to 11-year-olds participating in an ongoing cohort study, excluding those who had sleep apnea or who were born prematurely. Using BMI percentiles for age and sex, 17.5% of the children were considered overweight (BMI ≥95th percentile), 12.4% were at risk for overweight (BMI 85th-94th percentile), 8.1% were relatively underweight (BMI <20th percentile), and the remaining 62.0% were of normal weight (BMI 20th-84th percentile).
Main Outcome Measures
Health-related quality-of-life scores as determined by the Child Health Questionnaire–Parent Form 50, dichotomized into the bottom quartile or decile.
After adjustment for covariates (host factors and health status measurements), overweight children compared with normal weight children scored lower on the Psychosocial Health Summary (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.1-3.6) and on subscales measuring self-esteem (OR, 3.5; 95% CI, 1.9-6.3), physical functioning (OR, 2.8; 95% CI, 1.7-6.8), and effect on the parent's emotional well-being (OR, 2.0; 95% CI, 1.1-3.6). Compared with the normal weight group, children who are at risk for overweight scored significantly lower for physical functioning.
Overweight children have an increased odds of low scores for several health-related quality-of-life domains, suggesting the importance in considering such dimensions in programs aimed at further understanding obesity in children.
CHILDHOOD OBESITY is a major public health problem with increasing prevalence; approximately 30% of US school-aged children are defined as overweight or at risk for overweight.1 Children who are overweight are more likely to become overweight adults.2,3 Overweight is an important risk factor for cardiovascular disease, diabetes mellitus, and hypertension.4- 6 However, the effect of pediatric obesity on the activities of daily living and other aspects of health-related quality of life (HRQOL), to our knowledge, has not been well characterized.
Measures of HRQOL assess important aspects of health that are not detected by traditional physiological and clinical measurements. These aspects include the effect of a health condition on the child's daily activities, physical symptoms, social interactions, and emotional well-being. While there is strong evidence for the negative effect of obesity on HRQOL in adults, especially in the domains of general health perceptions, physical functioning, and emotional health,7- 9 these relationships have received less attention in children. Generic HRQOL measurements such as the Child Health Questionnaire–Parent Form 50 (CHQ-PF50) permit comparisons across different disease states and have been measured in pediatric conditions such as asthma, sickle cell anemia, and sleep apnea.10- 12
To our knowledge, no prior studies have assessed the association between a comprehensive multidimensional assessment of generic HRQOL and pediatric obesity. There are reports that obese children demonstrate more negative self-perceptions, decreased self-worth, increased behavioral problems, lower self-esteem, and lower body esteem and perceived cognitive ability.13- 17 However, because of methodological limitations, including small sample size, definitions of obesity that differ with current recommendations,14,15 and with nonvalidated measurements of HRQOL,15,16 it is difficult to generalize the conclusions of these studies.
The primary purpose of the present study was to evaluate the association between HRQOL and obesity in preadolescent children, aged 8 to 11 years. Information on preadolescent children, who may be at particular risk for functional limitations and life dissatisfaction, may direct behavioral interventions for improving the care of obese children. We hypothesized that with an increasing body mass index (BMI) (calculated as weight in kilograms divided by the square of height in meters), children would be reported as having decreasing levels of HRQOL, independent of other chronic health conditions. The second aim of the study was to describe relationships among participant characteristics, BMI status, and HRQOL to provide information concerning possible risk factors within overweight children for decreased HRQOL.
The analytic sample included 371 children, aged 8 to 11 years, drawn from the Cleveland Children's Sleep and Health Study cohort. This study is designed to assess the prevalence and correlates of sleep disorders and other health conditions in children. The cohort was assembled by randomized stratified sampling of full-term and premature neonates, born between 1988 and 1993, who were identified from the birth records of 3 Cleveland-area hospitals. Methods used to recruit subjects have been previously described.18,19 Children with sleep apnea (n = 16)(as identified by overnight sleep monitoring; apnea hypopnea index ≥5 or premature status (n = 328) (gestational age ≤36 weeks) were excluded from the analysis to reduce possible heterogeneity in the associations between HRQOL and obesity.10
Health-related quality of life was assessed with the CHQ-PF50, a parent report tool for measuring HRQOL in children aged 5 to 18 years.12 This inventory contains 50 items measuring domains of physical and emotional health, grouped into 2 single summary and 12 multi-item scales that use a 4- to 6-point ordinal scale to measure health and functional status. Each multi-item scale score is calculated by totaling contributions from each item and then scaling the total score to provide values from 0 (worst health) to 100 (best health). The Physical Health Summary and the Psychosocial Health Summary measurements are calculated from weighted combinations of individual subscales. The summary measurements are transformed into standardized scores with a mean of 50. Used in its entirety, the CHQ-PF50 provides information on children's social roles, emotional health, physical health, and family functioning (activities and cohesion). The CHQ-PF50 is validated and reliable for boys and girls of different ages and cultures and for parents with differing levels of education and marital and work status.12 In addition, data are available for children with chronic health conditions including asthma, epilepsy, cystic fibrosis, and juvenile rheumatoid arthritis.12 The specific subscales consist of the following: (1) physical functioning, (2) role/social–emotional/behavioral, (3) role/social–physical, (4) bodily pain, (5) behavior, (6) mental health, (7) self-esteem, (8) general health perceptions, (9) family cohesion, (10) parental impact–emotional, (11) parental impact–time, (12) family activities, (13) global general health, and (14) global behavior.
Height and weight were measured by trained research personnel. Body mass index percentiles for age and sex were categorized into the following 4 groups: (1) overweight (BMI ≥ 95th percentile), (2) at risk for overweight (BMI 85th-94th percentile), (3) relative underweight (BMI <20th percentile), and (4) normal weight (BMI 20th-84th percentile).20,21 Reference data from the 2000 Centers for Disease Control and Prevention BMI-for-age-and-sex growth charts were used.22
Asthma was specifically included as a covariate because of its reported association with obesity in the literature.23- 25 Children were categorized as having asthma if the parent reported having "ever been told by a teacher, school official, doctor, nurse or other health professional that [their child had] asthma."12(p371) Other chronic health conditions were aggregated into a single variable and identified by similar parental report of the following: chronic orthopedic, bone, or joint problems; chronic respiratory problems not including asthma; chronic rheumatic disease; developmental delay or mental retardation; diabetes mellitus; epilepsy; and other chronic conditions. Ethnic minority status was defined as nonwhite.
For continuous outcomes, comparisons were performed using the Wilcoxon or Kruskal-Wallis nonparametric tests. For binary outcomes, a low score was defined according to the distribution of scores in this sample as has been done in a previous study of HRQOL.26 The CHQ-PF50 outcomes were dichotomized into the bottom quartile for all subscales except for 3 highly skewed scales (physical functioning, partental impact–time, role/social–emotional/behavioral) for which the bottom 10th percentile was used. Differences in unadjusted categorical variables were tested using χ2 analyses or the Fisher exact test when expected cell counts were fewer than 5. Adjusted odds ratios, relating each explanatory covariate with each dichotomous outcome, were computed using multiple logistic regression analyses. Covariates included in each model were selected using a stepwise logistic regression procedure, retaining covariates that were significant at P<.15. Covariates considered were age, race, male sex, and having asthma or other chronic health conditions. Body mass index measurements were classified into the 4 categories described earlier; the reference group for these analyses was the normal BMI group, with other categories coded as "dummy variables." Analysis was performed using statistical software (SAS Version 8; SAS Institute, Cary, NC).
The protocol was approved by the institutional review boards of the university-based hospitals where the children had been born. Written informed consent was obtained from the parents or legal guardian of each child; assent was obtained from the child.
The general characteristics of the study population are given in Table 1. Based on the BMI categories, 17.5% of the children were overweight, 12.4% were at risk for overweight, 8.1% were underweight, and 62.0% were of normal weight.
The distributions for the 2 global summary scores and the 14 subscales are listed in Table 2, stratified by BMI categories. Compared with the normal weight group, children in the overweight group had significantly lower scores on the psychosocial health summary score (P<.001) and subscale scores for self-esteem (P<.001), parental emotional well-being (P = .02), physical functioning (P = .01), behavior (P = .001), global general health (P<.001), and global behavior (P = .02). Only the physical functioning subscale was significantly lower in the at risk for overweight group compared with the normal weight group (P<.01).
The proportion of children with low scores for the Psychosocial Health Summary scale and for the subscales self-esteem, physical functioning, and parental emotional well-being was increased in the overweight and at risk for overweight categories compared with the normal weight category (Table 3). After adjusting for covariates, overweight children had a 2-fold increased odds of a Psychosocial Health Summary score in the lowest quartile compared with the normal weight group. Overweight children also had a higher odds of having low self-esteem scores, low physical functioning subscale scores, and poorer parental emotional well-being scores. Similarly, children who are at risk for overweight had a 4-fold higher odds than normal weight children for lower physical functioning subscale scores. Underweight children had a 2-fold increased odds for lower self-esteem scores than normal weight children. The difference for the other summary scales and subscales according to BMI categories were not statistically significant.
This study describes variation of generic measurements of HRQOL in a well-characterized, large community-based sample of school-aged children across various BMIs. Our data suggest that measurements of HRQOL are decreased in children at both ends of the spectrum—those who are obese and those who are underweight. Children who are overweight have a 2 to 4 times increased odds of having low scores for psychosocial health, self-esteem, and physical functioning. Parents of children who are overweight also were more likely to evidence higher levels of emotional distress because of their children's health. Similarly, children who are at risk for being overweight have higher odds of having low physical functioning scores. Lower self-esteem also was observed in children who are underweight. Differences in scores were observed in a representative, population-based sample of relatively healthy children and were not attributable to differences in underlying comorbidity, ethnicity, or sleep apnea (a medical condition common in obese children).10
This is the first study, to our knowledge, to evaluate the relationship between a comprehensive multidimensional assessment of generic HRQOL and obesity in a pediatric population. Only 1 previous study reported decreased overall HRQOL in overweight children. However, the lack of a control group and potential selection biases limit the generalizability of those findings.27 The potential importance of our findings is suggested by a well-developed literature that identifies unique information derived from HRQOL measurements that is not captured by physiological measurements. Specifically, these measurements have been shown to discriminate among clinical subgroups and to predict disease progression, response to therapy, satisfaction with health care, and health care use.7,28,29
The finding that higher BMI scores are associated with lower Psychosocial Health Summary scores, but not Physical Health Summary scores, suggests that obesity in children is more closely associated with perceived limitations in psychological health rather than in physical health. Based on the content of the questions used to assess psychological health, it can be inferred that children with higher BMIs are more likely than normal weight children to be perceived by their parents as having feelings of anxiety and depression, of exhibiting aggressive or immature behavior, as having role limitations in their schoolwork and social activities, and as having low self-esteem. Their parents also report higher levels of emotional distress and little personal time because of their children's health or behavior.
Median self-esteem scores were significantly lower for the overweight group compared with the normal weight group. The self-esteem scale on the CHQ-PF50 assesses social confidence, school abilities, and self-regard and captures satisfaction with appearance, ability to get along with others, and life overall. The current study is consistent with prior research showing lower self-esteem in children and adolescents associated with obesity. Although some studies reported no association of self-esteem and obesity,30,31 small sample sizes and the study of very young, selected samples, may account for these negative findings.
There is likely population heterogeneity regarding both the cause and consequences of obesity.32 The literature is consistent with different associations between obesity and self-esteem according to gender and pubertal status, suggesting potentially more negative self-esteem among prepubertal obese females compared with males, and in pubertal compared with obese males.14,33 Our findings relating low self-esteem and BMI were observed in a primarily prepubertal population and affected males as well as females (no evidence for sex-specific effects were seen; data not shown). We did not, however, examine individual factors that may predispose certain children to obesity-associated problems, and we cannot determine which obese children are most likely to manifest problems with psychological functioning and self-esteem.
The lack of significant variation in the Physical Health Summary score with BMI contrasts to reports of HRQOL in adults where physical functioning has been found to be more strongly associated with obesity than psychological status.34- 36 We did, however, observe selective limitations in physical functioning (ie, as measured by the physical functioning subscale) in overweight children. The content of this subscale indicates they were perceived to be less proficient in performing vigorous physical and self-care activities owing to health. It is possible that more impairment in physical functioning may have been apparent had the children in our sample been more obese. Alternatively, broad obesity-associated physical limitations may preferentially occur in adults.
There are several limitations of the study including the inability to evaluate causality, the narrow age range of the sample, and using only 1 informant concerning the child's HRQOL. Stronger associations may have been observed had our study included adolescents, a population that may be particularly sensitive to the negative effect of obesity, especially regarding dimensions such as self-esteem.33 Using parental reports of HRQOL and comorbidity, as opposed to children's self-report, may not be as accurate.37,38 This may have overestimated our results as some studies have demonstrated that parental distress may bias parents to overreport problems with behavioral and emotional functioning compared with the children's own ratings.39,40 Moreover, mothers of obese children may have a higher level of obesity than mothers of nonobese children and their parental report may have been adversely affected by their own obesity-associated distress. Future studies of pediatric obesity and HRQOL should also consider parental obesity.
Dose-effect relationships between BMIs and the proportion of children with low scores were suggested for the Psychosocial Health Summary score, and the self-esteem and parental emotional well-being subscales (indicated by increasing odds ratios that were highest for the overweight and intermediate for the at risk for overweight groups). However, in this generally healthy population-based sample, the overall decrease in scores was relatively small. Although the clinical significance of average absolute decrements of approximately 5% to 15% are unclear, they point to the potential importance of considering specific HRQOL dimensions when attempting to understand the causes and consequences of pediatric obesity, especially dimensions associated with psychosocial functioning and self-esteem.
No significant associations were demonstrated for several specific quality-of-life subdomains. This may be owing to the fact that the CHQ-PF50 is a generalized assessment of quality of life and may be less sensitive than instruments designed to evaluate a specific disease process.37 Further investigations, using both general and disease-specific instruments, may further elucidate HRQOL in children who are overweight or at risk for being overweight.
This study demonstrates an association between obesity and decreased quality of life, specifically dimensions related to psychosocial health, self-esteem, physical functioning, and the impact on parental emotional well-being, in school-aged children. Although our data do not address causality, it is possible that programs aimed at reducing obesity may help improve HRQOL for some children. Additionally, overweight children may benefit from interventions that address issues related to psychosocial functioning and self-esteem. Further research aimed at understanding whether the observed relationships are based on causal pathways and the direction of any causality are indicated.
Corresponding author and reprints: Susan Redline, MD, MPH, Department of Pediatrics, Rainbow Babies & Children's Hospital, 11100 Euclid Ave, Cleveland, OH 44106 (e-mail: email@example.com).
Accepted for publication May 29, 2003.
This study was supported in part by grants RO1 HL60957-04 (Dr Redline), K23 HL04426 (Dr Rosen), K23 MH0183 (Dr Palermo), RO1 NR02707, HL07567, and M01 RR00080-39 from the National Institutes of Health, Bethesda, Md.
We gratefully appreciate the work of Sarah Bivins, Judy Emancipator, MA, Najla Golebiewski, and Susan Surovec for their invaluable assistance with data collection, analysis, and patient recruitment. We are also extremely grateful to the families who participated in this study.
To our knowledge, this is the first study to evaluate the relationship between a comprehensive multidimensional assessment of generic HRQOL and obesity in the pediatric population. Measurements of HRQOL assess important aspects of health not detected by traditional physiological and clinical measurements. This study evaluated the association between quality of life and obesity in preadolescent children in a large community-based sample of school-aged children.
Children who are at risk for or who are overweight have odds 2 to 4 times greater for lower HRQOL scores for psychosocial health, self-esteem, and physical functioning. Parents of children who are overweight also were more likely to evidence higher levels of emotional distress because of their children's health. Being relatively underweight also was associated with lower self-esteem. This suggests that early identification of children who are obese and have reduced HRQOL may direct behavioral interventions for those particularly in need of psychosocial assistance.
Friedlander SL, Larkin EK, Rosen CL, Palermo TM, Redline S. Decreased Quality of Life Associated With Obesity in School-aged Children. Arch Pediatr Adolesc Med. 2003;157(12):1206-1211. doi:10.1001/archpedi.157.12.1206