How Do Children with Eating Disorders Differ from Adolescents with ...

Journal of Adolescent Health 39 (2006) 800 – 805

Original article

How Do Children with Eating Disorders Differ from Adolescents with Eating Disorders at Initial Evaluation? Rebecka Peebles, M.D.a,*, Jenny L. Wilson, B.A.a, and James D. Lock, M.D., Ph.D.b b

a Division of Adolescent Medicine, Department of Pediatrics, Stanford University School of Medicine, Stanford, California Division of Child and Adolescent Psychiatry and Child Development, Department of Psychiatry, Stanford University School of Medicine, Stanford, California Manuscript received December 13, 2005; manuscript accepted May 19, 2006

Abstract

Purpose: To compare the clinical presentation of children with eating disorders (ED) to that of adolescents with ED. Methods: Demographic, medical, and psychiatric data of all 959 in- and outpatients (85 males, 874 females) 8 –19 years of age diagnosed with ED that presented to an academic center between 1997 and 2005 were examined via retrospective record review. Young patients (n ⫽ 109) were defined as aged ⬍ 13 years at presentation, and older patients (n ⫽ 850) ⱖ 13 years and ⬍ 20 years. Results: Compared with older adolescents (mean 15.6 years, SD 1.4), younger patients (mean 11.6 years, SD 1.2) were more likely to be male (␹2 ⫽ 9.25, p ⬍ .005) or diagnosed with eating disorder not otherwise specified (EDNOS) (␹2 ⫽ 5.09, p ⱕ .05), and less likely to be diagnosed with bulimia nervosa (BN) (␹2 ⫽ 13.45, p ⱕ .001). There were no significant differences in anorexia nervosa (AN) diagnoses between groups. Young patients were less likely to report purging (␹2 ⫽ 26.21, p ⬍ .001), binge eating (␹2 ⫽ 26.53, p ⬍ .001), diet pill (␹2 ⫽ 13.31, p ⬍ .001) or laxative use (␹2 ⫽ 6.82, p ⬍ .001) when compared with older teens. Young patients weighed less in percentage ideal body weight (p ⬍ .05), had a shorter duration of disease (p ⬍ .001), and had lost weight more rapidly than older adolescent patients (p ⱕ .001). Conclusions: There are important diagnostic and gender differences in younger patients. Young ED patients presented at a lower percentage of ideal body weight and had lost weight more rapidly, which may put them at higher risk for future growth sequelae than their older counterparts. © 2006 Society for Adolescent Medicine. All rights reserved.

Keywords:

Adolescent; Child; Eating disorders; Anorexia nervosa; Bulimia nervosa

Anorexia nervosa (AN) has been described in patients as young as seven years old [1,2]. Because eating disorders (ED) are less common in very young patients, little is known about their presentation in comparison with older youth. This study evaluates differences in presentation between young patients diagnosed with ED and their older adolescent counterparts. Although the prevalence of diagnosed AN and bulimia

*Address correspondence to: Dr. Rebecka Peebles, Division of Adolescent Medicine, Stanford University School of Medicine, 1174 Castro St., Suite 250A, Mountain View, CA 94040. E-mail address: [email protected]

nervosa (BN) is as low as 1% in children and young adolescents, a preoccupation with weight and eating disturbances is common at this age [3,4]. In school-based studies of 8 –13 year-olds, 20%–56% report dieting, 44%–71% report exercising to lose weight, 1.4%–10% report purging or using diet pills or laxatives, and 4%– 6.5% report binge eating regularly [5–9]. When eating disturbance was assessed in school-based studies of 2279 10 –14-year-olds and 318 7–13-year-olds using the Children’s Eating Attitudes Test, 10.5% and 6.9%, respectively, scored ⬎ 20, the clinical threshold for disordered eating [8,9]. There are unique challenges to understanding children and young adolescents with ED. Because they are un-

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R. Peebles et al. / Journal of Adolescent Health 39 (2006) 800 – 805

common and may present with unusual features, eating disorders in this age group are often misdiagnosed [10 – 14]. In addition to a lack of recognition within the medical community, children with ED do not fit neatly within a psychiatric diagnostic category. They may not meet criteria for AN because they may lack features such as body dissatisfaction [2,14], they may have poor growth but not be less than 85% of ideal body weight, and if they have not reached menarche, may not necessarily meet criteria for amenorrhea. Delaying the diagnosis of ED in children can have deleterious effects on their medical and mental health. Some investigators have proposed dropping the menstrual criteria entirely from the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) in the diagnosis of young patients with anorexia nervosa [4,14]. Studies have found that young patients with ED are more likely to be male than older ED patients [4,11,12,14,15]. In addition, children and young adolescents with ED often have a high incidence of other psychiatric diagnoses such as depression or obsessive compulsive disorder [4,10,12,14,16]. The severity of illness and outcomes in young patients has not been well studied. No studies have compared the percentage ideal body weight of children and young adolescents with that of older adolescents. One study comparing 20 prepubescent to 20 postpubescent patients with AN found that 45% of the younger group had lost at least 30% of their body weight as compared with only 15% of the older group [15]. However, the statistical significance of this result was not reported. Another study comparing 9 –14-year-old ED patients to 15–19-year-old patients found no difference between the groups in the rate of weight loss [17]. One study of 21 9 –12-year-old patients with AN, aged 7–12 years at the onset of illness, found that patients aged 7–10 years at onset had a delay in diagnosis that was twice as long (mean 13 months) as patients aged 11–12 years at onset (6.5 months) [10]. A younger age at presentation has been shown to predict readmission to the hospital and a worse overall outcome [18 –20]. Only three studies have been published on patients with an average age of less than 13 years at presentation for an ED, a total of 84 subjects, all of whom were diagnosed with AN [10,12,16]. No study has focused on varied ED diagnoses in patients younger than 13 years of age. This study compares a larger sample of younger ED patients with older ED adolescents. We hypothesized that younger ED patients, when compared with older adolescents, would more often be male, have lower percentage ideal body weight, be less likely to engage in purging behaviors, be more likely diagnosed with eating disorder not otherwise specified (EDNOS), and have a shorter duration of disease due to their young age.

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Methods Subject Selection We identified all patients aged 8 –19 years evaluated in a treatment program for children and adolescents with ED at an academic medical center from January 1997 through August 2005. Charts were identified by searching medical records and clinical databases for all patients aged 8 –19 years, diagnosed with AN, BN, or EDNOS. Diagnoses were made using DSM-IV criteria at presentation by a child psychiatrist expert in the assessment of children and adolescents with ED, and record review substantiated all diagnoses. Patients were also medically assessed by an adolescent medicine specialist with expertise in ED. Both inpatients and outpatients who presented for evaluation were included. Patients not diagnosed at presentation with an ED were excluded from analysis. Once a potential case was identified, a comprehensive medical record review was performed for the initial visit and clinical parameters at presentation were noted. Medical, psychiatric, nutrition, and nursing notes of information obtained from both parents or guardians and children were reviewed, along with intake demographic information. There were 959 patients identified as meeting these criteria, with 109 patients younger than 13 years at presentation. A waiver of informed consent and a HIPAA-compliant waiver of individual authorization were granted, and all data collection protocols were approved by our Panel on Medical Research in Human Subjects and compliant with the Health Insurance Portability and Accountability Act of 1996. Variables and Covariates Abstracted information included demographic factors (i.e., age, self-reported ethnicity, gender), height, weight (kg), reported prior maximum/minimum weights, vital signs at presentation, sexual maturity rating (SMR) on exam and menarchal status, ED diagnosis, length of disease, other medical and comorbid psychiatric conditions, eating behaviors, and medications. Height and weight at presentation were measured by trained staff using standard anthropometric procedures. Relevant laboratory findings and electrocardiograms from the time of presentation were also reviewed. The primary predictor variable for these analyses was age as a dichotomous variable: ⬍ 13 years of age and ⱖ 13 but ⬍ 20 years of age. Percentage Ideal Body Weight Body mass index (BMI) was calculated for each patient based on the recorded height and weight at presentation and using the equation: BMI ⫽ weight in kilos/(height in meters)2. The ideal body weight was calculated using the gender-specific 2000 Centers for Disease Control and Prevention (CDC) BMI-for-age growth charts for children and adolescents aged 2–20 years and based on data collected by

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the National Health and Nutrition Examination Survey (NHANES) (http://www.cdc.gov/growthcharts). The 50th percentile BMI for exact age at presentation on the CDC chart was established as the ideal BMI for each patient and used to calculate an ideal body weight, together with the height at presentation. Rate of Weight Loss Reported maximum weights and dates of maximum weights before presentation were recorded whenever available in the medical record. Total weight loss before presentation was the maximum weight minus the weight at presentation. Total percentage weight loss was the total weight loss divided by the maximum weight, multiplied by 100. The rate of weight loss was the total percentage weight loss divided by the months from the date of maximum weight to the date of presentation. If the maximum weight was the weight at presentation, the total weight loss was zero, as was the rate of weight loss. Eating Behaviors Patients were classified as purgers if they reported selfinduced vomiting in the month before presentation. Reported purging behaviors before the month before presentation were also recorded and categorized as lifetime purging. Binge eating behaviors were reported in less detail in the medical record. As a result, patients were classified as binge eaters if they reported binge eating behaviors at the time of presentation, and nonbinge eaters if they did not. Reports of past binge eating were recorded and categorized as lifetime binge eating. Laxative use and diet pill use was recorded. Comorbid Psychiatric Diagnoses Subject records were examined for any other comorbid psychiatric diagnosis made by a child psychiatrist at presentation using DSM-IV criteria. Such diagnoses were clustered into four categories: mood (e.g., depression, bipolar disorder, dysthymic disorder), anxiety (e.g., panic attacks, obsessive-compulsive disorder, generalized anxiety disorder), externalizing (e.g., oppositional defiant disorder, conduct disorder, attention deficit hyperactivity disorder), and developmental (e.g., autism, pervasive developmental disorder, mental retardation). Psychiatric medications reported by patients at presentation were grouped into the following categories: antidepressants, anxiolytics, mood stabilizers, amphetamines, and antipsychotics. Statistical Analysis Results were analyzed using descriptive testing and 95% confidence intervals, Pearson’s correlation analyses, chisquared testing, and independent variables t-testing on SPSS v13.0 software (SPSS Inc., Chicago, Illinois).

Results A total of 959 patients were analyzed: 109 (11.4%) patients under 13 years of age and 850 (88.6%) patients aged 13–19 years at presentation to our program. The mean age of the younger patient subset was 11.6 years (SD 1.2); the mean age of the older adolescent subset was 15.6 years (SD 1.4). Most of the young patients were prepubertal: 76.1% of young females (n ⫽ 91) were premenarchal, compared with 7.0% of older females (n ⫽ 773). SMR of breast/genitourinary and pubic hair was documented in 775 and 811 subjects, respectively. These two SMR scores were highly correlated (r ⫽ .879, significant at the .01 level), and so we analyzed only SMR of pubic hair, as we had more subjects with this documentation. Sixty percent of younger children were SMR 1–2 pubic hair (n ⫽ 58/96) vs. only 2.7% of older adolescents (n ⫽ 19/715), and this difference was highly significant, as expected (␹2 ⫽ 328.6, p ⬍ .001). Other demographic and clinical characteristics of the overall dataset are noted in Tables 1 and 2. A comparison of the two age groups is seen in Table 3. Younger ED patients were more likely to be male, and were less likely to report purging or binge eating behaviors, either at presentation or in their lifetime. There was a significant difference in diagnoses between groups, with 61.5% of young patients diagnosed with EDNOS (␹2 ⫽ 5.09, p ⱕ .05) compared with 50.0% of older patients, and only 1.8% of young patients diagnosed with BN compared with 14.4% of older patients (␹2 ⫽ 13.45, p ⱕ .001). There were no significant differences in anorexia nervosa (AN) diagnoses between groups. Younger patients were also significantly less likely to have ever tried diet pills or laxatives to lose weight. Although there were no differences between groups in overall or subgroups of psychotropic drug use, and overall psychiatric diagnoses, younger patients trended toward being less likely than older patients to be diagnosed with a mood cluster diagnosis. From a medical standpoint, young patients weighed less in percentage ideal body weight than did older adolescents, and had a shorter duration of disease before presentation. Younger patients did not differ significantly from older patients in the percentage of body weight lost before presentation or the length of stay if admitted to the hospital. However, younger patients had a significantly faster rate of weight loss than older patients. Discussion This study is the first to describe a large sample of young children with different types of ED, and to compare them with older teens on multiple measures. Series of young patients with ED to date have focused on smaller samples of patients with AN, with “young” typically defined as prepubertal at time of onset. This liter-


ature suggests that children and young adolescents with ED are more likely to be given a diagnosis of EDNOS than AN or BN, due to the difficulty of younger patients meeting classic AN or BN criteria, and because younger patients are less likely to binge, purge, or use laxatives or diuretics [15,17,21]. Our results were consistent with our original hypotheses and, in general, with the extant medical literature. We found that young ED patients were more likely to be boys, have a shorter duration of disease and lower percentage ideal body weight at presentation. They were also more likely to be diagnosed with EDNOS, less likely to be diagnosed with BN, and to not have engaged in other risk behaviors, including purging, laxative or diet pill use. That younger children engage in fewer bingepurge behaviors may suggest an improved prognosis [22]. However, 19.2% of young patients had indeed tried purging to control their weight during their lifetime, and

Table 1 Demographic and clinical description— overall dataset

Gender (n ⫽ 959) Male Female Ethnicity (n ⫽ 933) Caucasian Asian Hispanic African-American Pacific Islander Other Diagnosis (n ⫽ 959) Anorexia nervosa Bulimia nervosa Eating disorder NOS Admission status (n ⫽ 959) Admitted to hospital or admission recommended Purging (n ⫽ 958) Last month Lifetime Binge eating (n ⫽ 847) At presentation Lifetime Laxative use, lifetime (n ⫽ 913) Diet pill use, lifetime (n ⫽ 825) Psychiatric diagnoses (n ⫽ 959) Mood Anxiety Externalizing Developmental Psychiatric medications (n ⫽ 948) Antidepressants Anxiolytics Mood stabilizers Amphetamines Antipsychotics

n

%

85 874

8.9 91.1

723 83 64 13 2 48

75.5% 8.9% 6.9% 1.4% .2% 5.1%

343 124 492

35.8% 12.9% 51.3%

659

68.7%

303 404

31.6% 42.1%

244 285 154 141

28.8% 33.6% 16.9% 17.1%

278 98 24 3

29.0% 10.2% 2.5% .3%

258 16 17 15 29

27.2% 1.7% 1.8% 1.6% 3.1%

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Table 2 Descriptive statistics of overall dataset

Age in years Months of disease %IBW CDC Percent weight loss Time weight loss (mos) Rate weight loss (%/mo) Length of stay (days) if admitted within 2 weeks

n

Mean

Standard Deviation

959 955 959 893 858 856 652

15.1 14.4 89.9 18.3 12.0 2.6 19.1

1.9 14.3 19.0 10.6 11.4 2.8 12.4

33% of young patients had been diagnosed with a comorbid psychiatric disorder. Also concerning was the significantly faster rate of weight loss in younger patients. Because the majority of our young patients were prepubertal, this rapid rate of weight loss could be especially damaging, as it occurred when they should be achieving critical growth and bone development. There are limitations to this study. This is a retrospective sample using baseline characteristics of patients, and conclusions about prognosis or treatment response cannot be derived from these data. Also, data are derived from a clinical setting and medical record, rather than structured interviews. As a result, data are not perfectly standardized, and there may be treatment provider differences in data collection that cannot be adequately examined here. Finally, a sample of 109 young ED patients at a tertiary referral center, although the largest of its kind, remains too small to be interpreted beyond this clinical setting. Although there are relatively few young patients with ED, our dataset suggests they share many characteristics with older adolescents, including comorbid psychiatric diagnoses, psychotropic medication use, and rates of medical admission. The increased rate of EDNOS diagnosis is important and highlights the need for further examination of this diagnostic category in young children. Our data support that DSM-IV diagnostic criteria may not easily apply to young children, and that their eating behavior profile differs somewhat from older adolescents. These findings deserve further prospective study and highlight the importance of early recognition and improved treatment models for young children with disordered eating. No studies have addressed this, as it is difficult to obtain adequate sample sizes for study. Because of the developmental age of these patients, it may be that a family treatment model is an ideal one for this age group [23]. Future studies should focus on longitudinal follow-up for treatment response, relapse rates, and long-term prognosis, to better clarify the myriad issues presented in young patients with eating disorders.

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Table 3 Comparison of groups

Gender % Male Diagnosisa % AN % BN % EDNOS Admission status % Admitted within 2 weeks Purging Last month Lifetime Binge eating Presentation Lifetime Laxative use Lifetime Diet pill use Lifetime Other diagnoses Depression Any psychiatric Medication Psychiatric Months of disease % Ideal body weight % Weight loss Time weight loss (mos) Rate weight loss (%/mo) Length of stay (days) a

Subjects aged ⬍ 13 years

Subjects aged 13 through 19 years

n ⫽ 109 16.5% n ⫽ 109 36.7% 1.8% 61.5% n ⫽ 109 70.6% n ⫽ 109 12.8% 19.3% n ⫽ 88 9.1% 9.1% n ⫽ 94 4.3% n ⫽ 80 2.5% n ⫽ 109 21.1% 33.0% n ⫽ 108 25.0% n ⫽ 108 9.8 n ⫽ 109 86.4% n ⫽ 97 16.7% n ⫽ 93 8.0 n ⫽ 92 4.0 n ⫽ 75 19.3

n ⫽ 850 7.8% n ⫽ 850 35.6% 14.4% 50.0% n ⫽ 850 68.5% n ⫽ 849 34.0% 45.0% n ⫽ 759 31.1% 36.5% n ⫽ 818 17.2% n ⫽ 745 18.7% n ⫽ 850 30.0% 36.6% n ⫽ 840 30.5% n ⫽ 847 14.8 n ⫽ 850 90.3% n ⫽ 796 18.4% n ⫽ 765 12.4 n ⫽ 764 2.5 n ⫽ 577 19.1

Significance

95% confidence interval

␹2 ⫽ 9.25, p ⬍ .005

n/a

NS ␹2 ⫽ 13.45, p ⬍ .001 ␹2 ⫽ 5.09, p ⬍ .05

n/a n/a n/a

NS

NS

␹2 ⫽ 20.01, p ⬍ .001 ␹2 ⫽ 26.21, p ⬍ .001

n/a n/a

␹2 ⫽ 18.61, p ⬍ .001 ␹2 ⫽ 26.53, p ⬍ .001

n/a n/a

␹2 ⫽ 10.63, p ⱕ .001

n/a

␹2 ⫽ 13.31, p ⬍ .001

n/a

␹2 ⫽ 3.72, p ⫽ .054 NS

n/a n/a

NS

n/a

p ⬍ .001

⫺7.9 to ⫺2.4

p ⬍ .05

⫺7.7 to ⫺.07

NS

NS

p ⬍ .001

⫺6.4 to ⫺2.4

p ⱕ .001

.6 to 2.5

NS

NS

Compares patients in diagnostic category to patients not in the diagnostic category.

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