PAPER Possible risk factors in the development of eating disorders in overweight pre-adolescent girls

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1 (2002) 26, ß 2002 Nature Publishing Group All rights reserved /02 $ PAPER Possible risk factors in the development of eating disorders in overweight pre-adolescent girls A Burrows 1 and M Cooper 2 * 1 Rowden House, Chippenham, UK; and 2 Isis Education Centre, Warneford Hospital, Oxford, UK OBJECTIVES: To investigate concerns about weight, shape and eating, dietary restraint, self-esteem and symptoms of depression in overweight girls. To investigate the relationship between concerns and self-esteem and depressive symptoms in this group. METHOD: Eighteen overweight girls and 18 average-weight girls completed the child version of the Eating Disorders Examination, the Harter Self-Perception Profile and the Short Moods and Feelings Questionnaire. RESULTS: Overweight girls had more concerns about weight, shape and eating and attempted dietary restraint more often. They had more negative self-esteem related to their athletic competence, physical appearance and global self-worth and more symptoms of depression. There was an association between concerns and self-esteem based on physical appearance in the overweight group. CONCLUSION: Overweight girls show some of the psychological features associated with the development of eating disorders, including a link between concerns and self-esteem based on physical appearance. This may help to explain why childhood obesity increases the risk of a later eating disorder. (2002) 26, doi: =sj.ijo Keywords: overweight girls; obesity; eating disorders; depression; self-esteem Introduction Childhood obesity is one of the risk factors for the later development of bulimia nervosa 1,2 and binge eating disorder. 3 It has also been associated with the development of anorexia nervosa. 4,5 One possible reason for this may be that overweight children show greater concern with weight, shape and eating and greater tendency to dietary restraint than average weight children. These are key features of the specific psychopathology of eating disorders, 6 and have an important role in cognitive models of anorexia nervosa and bulimia nervosa. 7 9 Low self-esteem and symptoms of depression are also possible outcomes of obesity in childhood. 10,11 Both of these may also increase the risk of developing an eating disorder. 2,3 Recently conducted research suggests that low self-esteem, including self-esteem based on weight and shape, may play a particularly key role in cognitive models of eating disorders. 12 Depressive symptoms *Correspondence: M Cooper, Isis Education Centre, Warneford Hospital, Oxford OX3 7JX, UK. myra.cooper@hmc.ox.ac.uk Received 2 January 2001; revised 19 February 2002; accepted 25 February 2002 are also commonly found in those with an eating disorder, although it is often argued that these tend to be secondary to the eating disorder. Gender is a known risk factor for eating disorders: these disorders are much more common in women than in men. To date, therefore, most research has focused on women. As yet it is unclear whether the issues or nature of the relationship to obesity are exactly the same for men and women. This paper will, therefore, focus on girls. Research in young girls indicates that many are concerned about their weight or shape. For example, a recent study 13 found that more than one in y-old girls (not selected for obesity) were concerned about their weight or shape, and this prevalence rate increased with age to almost one in five of y-olds. Importantly, among the older adolescents, concern about weight or shape was associated with disturbance in eating habits. Weight and shape concerns are also related to weight, with heavier girls being more concerned about these issues. 14,15 However, little research has been conducted into weight, shape and eating concerns and dietary restraint in overweight children. It has been suggested that, in girls who are overweight, this concern is likely to be particularly

2 prominent, perhaps due to increased self-consciousness, and the social stigma associated with obesity. 16 Nevertheless, this has not yet been investigated in a sample consisting of overweight girls. Dieting has also not often been investigated in overweight children. Not only is the proportion of women dieting increasing, but the age at which girls begin to be concerned about their weight and shape is getting lower. 17 One study 18 reported that some children as young as 9 y old attempted to restrain their eating. Again, attempts at dieting seem to be more common in girls who are heavier. 14 As with concerns about weight and shape, dietary restraint is likely to be particularly prevalent amongst girls who are overweight. Nevertheless, this has yet to be investigated in a sample of overweight girls. There has been little research into self-esteem in overweight children. One study 19 found no difference in selfesteem between obese and normal-weight children, but another 16 found poor self-esteem in a group of 7 12-y-old children who were at least 20% overweight. This study used the Harter Self-Perception Profile for Children. 20 Another, 10 in a study of 8 11-y-olds, also found evidence of lower selfesteem in obese children, using the same measure. Difference in measure used may help explain these conflicting findings. The current study will use the Harter Self-Perception Profile. The advantage of this measure, unlike that used in the study by Wadden and colleagues, 19 is that it measures self-esteem in several different domains. There has also been little research into symptoms of depression in overweight children. Although one study 11 found that obese children rated themselves as more depressed than non-obese children, another 21 failed to find evidence of depressive symptoms using the Moods and Feelings questionnaire. 22 However, this may be partially due to the age of Hopman s sample, 21 the majority of whom were under 10 y of age. It has been suggested that symptoms of depression rise steadily towards adolescence with a marked increase during the 11 12th year of age. 13 Recently, it has been suggested that the presence, or conjunction, of both low self-esteem and concerns about weight and shape are necessary for an eating disorder to develop. 12 Covariation of these general and specific features may, therefore, increase the risk of developing an eating disorder. There is some evidence that weight and shape concerns are associated with low self-esteem in girls. 18 However, the relationship between these in a group of overweight girls has not yet been investigated. In summary, there is little research on weight, shape and eating concerns, dietary restraint, self-esteem or symptoms of depression in objectively overweight girls. The covariation of these general and specific features has also not yet been investigated in this group. Ideally, a longitudinal design is needed to see whether childhood obesity predicts the development of features related to eating disorders. This seems premature (and costly) given that we do not yet know whether the features exist, or are associated, in this group. The aim of this study, therefore, will be to investigate the presence of concerns about weight, shape and eating and dietary restraint in overweight girls, compared to those of average-weight girls. These will be measured by the Child Eating Disorder Examination (CH-EDE 23 ). The study will also examine the relationship of concerns to self-esteem and depression. The prediction of the study is that girls in the overweight group will have more concerns about their weight, shape and eating and will show more attempts at dietary restraint, than those in the average-weight group. Girls in the overweight group will also have more negative ratings of self-esteem and higher ratings for symptoms of depression. Finally, there will be an association between concerns about weight, shape and eating, dietary restraint and self-esteem and symptoms of depression in the overweight group. The target age for this study will be y-old girls in their first year at secondary school. This is a time when there seems to be an increasing concern about weight, shape and eating. 24 It is also a crucial time for the development of symptoms of depression, 13 and possibly also for selfesteem. 21 Method Participants The participants were y-old girls in year 7 of mainstream secondary school. Index group. The index group consisted of girls with a body mass index (BMI) of 23 or above, which corresponds to a weight-for-height ratio of at or above 120% for their age. 25,26 Control group. The control group was girls with BMI of For their age this range represents a weight-forheight ratio of approximately %. 25,26 Measures Height and weight. Self-reports of height and weight were used to calculate body mass (BMI) for recruitment of participants to the study. Those who participated were then weighed and measured at the time of the interview. Eating Disorders Examination for Children (CH-EDE) The Eating Disorders Examination 27 is a standardised semistructured interview schedule for the assessment of the specific psychopathology of eating disorders. It has good psychometric properties, 28,29 although no published data exists on the specific psychometric properties of the child version. For example, internal consistency ratings for subscales range from 0.68 to 0.90, 29 and sub-scales discriminate eating-disordered patients from normal controls and dieters. 29 The measure has been modified for use with children (Child Eating Disorders Examination for Children, 1269

3 1270 CH-EDE 23 ). It has four sub-scales measuring Weight Concern, Shape Concern, Eating Concern, Restraint and a Global Concern scale derived from the four sub-scales. Street) Group, who were responsible for adapting the adult version. Self-perception profile for children This is a 36-item self report measure of self-esteem 20 which provides a profile of the child s perceived competence in five areas Scholastic Competence, Social Acceptance, Athletic Competence, Physical Appearance and Behavioural Conduct and also gives a rating of Global self-worth. It is a common measure of self-esteem in this age group, and has been used in several of the studies mentioned above. It has good psychometric properties. 20 Data analysis The data was analysed using the statistical package SPSS. 31 Analysis of CH-EDE and SMFQ data used non-parametric tests, ie Mann Whitney U and Spearman correlation coefficients as it did not meet the criteria for parametric tests. t- Tests were used to analyse the Harter Self-Perception Profile sub-scales as these met the criteria for parametric analysis. Because a relatively large number of correlations were carried out the significance level for these was set at Short Mood and Feelings Questionnaire. The Short Mood and Feelings Questionnaire (SMFQ 30 ) is a 13-item self report measure designed for 8 17-y-olds for assessment of core depressive symptomatology, or as a screening measure for epidemiological studies. Each statement is responded to on a 3-point scale of true, sometimes true or not true. The measure has good psychometric properties. 30 Procedure Recruitment and screening. Fourteen secondary schools (11 state and three independent schools) were approached with regard to taking part in the study by distributing letters to all year 7 girls. Six state schools, but none of the independent schools, agreed to participate. A total of 650 recruitment letters with reply slips addressed to the investigator were distributed by the six schools. No further involvement of the schools was required. Girls were asked to take part in a study of eating habits. If interested they returned the reply slip. They were then contacted by telephone; the study was explained further, they had an opportunity to ask questions and, if still interested, an appointment was made for them to participate. Informed consent was obtained from girls and their mothers before proceeding with the interview. No financial compensation was offered, but all participants (and schools who took part) received a summary of the study findings. Those who met the criteria for the index group were identified and then approximately matched for height, birth date and school with a girl within the average BMI range. Eighteen girls met criteria for the index group, and were recruited, thus 18 girls were also recruited for the control group. Audio-taped interviews then took place in the participants homes. Each interview took approximately h. The interviews were conducted by one of the investigators (AB) who had received detailed, supervised training in the administration of the EDE from the Oxford Group (who developed it). She had also received extensive training in the use of the CH-EDE from the London (Great Ormond Results Of the 650 letters distributed to six schools, 139 reply slips were returned (21.4%), of which 17 were anonymous (usable replies: 19% of those sent out). From these replies 18 girls were identified as having BMIs of 23 or above. At this age this equates to a weight-for-height ratio of 120% or above. These 18 girls constituted the index group and were then matched for height, age and school with 18 girls with BMIs of 16 19, which equates to a weight-for-height ratio of approximately % of expected weight-for-height for their age. Five potential participants from the control group declined to take part in the study, and were replaced from the pool of responders. All the girls who participated were in year 7 of state secondary school. The mean age of the index group at the time of the interview was 11 y 9.6 months and of the control group 12 y. A t-test showed that this difference was not significant. The mean weight-for-height ratios, and height centiles related to age, of the two groups are shown in Table 1, together with mean BMI scores. Six of the index group had reached menarche, whereas none of the control group had. This was a significant difference (Fisher s exact test, w 2 ¼ 25.6, d.f. ¼ 2, P <.001). Using Mann Whitney tests for between group differences, the index group had significantly higher scores than the control group on the Weight Concern, Shape Concern, Eating Concern and Restraint sub-scales of the CH-EDE. Table 1 Mean weight-for-height ratios, height centiles and BMI scores by group Index group Control group M (s.d.) M (s.d.) t (d.f.) Weight-for-height ratio (16.35) (6.88) 9.82 (34)** Height centiles related to age (26.27) (35.88) 1.86 (34) Body mass index (2.99) (1.24) 9.41 (34)* *P < 0.01; **P <

4 Mean scores for the two groups and results of statistical analyses can be seen in Table 2. There was no significant difference between the two groups in their reported eating of main meals, ie breakfast, lunch and supper but the index girls reported eating significantly fewer mid-morning snacks than the control group, using the CH-EDE (index group, M ¼ 3.4, s.d. ¼ 1.5; control group, M ¼ 4.7, s.d. ¼ 1.38; U ¼ 1.5, P ¼ 0.01, one-tailed). The index group also reported eating significantly fewer evening snacks than the control group (index group: M ¼ 2.1, s.d. ¼ 2.2; control group: M ¼ 3.6, s.d. ¼ 2.2; U ¼ 98.0, P < 0.025, one-tailed). Like the finding for the Restraint sub-scale above, this also suggests that the index group may have been attempting to restrain their eating more than the control group. There were no significant differences between the two groups, using t-tests for independent samples, on the Harter Self-Perception Profile sub-scales for Behavioural Conduct (index group, M ¼ 18.7, s.d. ¼ 3.1; control group, M ¼ 19.7, s.d. ¼ 2.8), Scholastic Competence (index group, M ¼ 17.3, s.d ¼ 4.1; control group M ¼ 17.5, s.d. ¼ 3.6) or Social Acceptance (index group M ¼ 18.4, s.d. ¼ 2.97, M ¼ 18.7, s.d. ¼ 3.3). However, the index group showed significantly more negative perception than the control group, on the sub-scales for Athletic Competence (index group, M ¼ 13.7, s.d. ¼ 1.1; control group, M ¼ 17.9, s.d. ¼ 3.7; t ¼ 3.60, d.f. ¼ 34, P ¼ 0.001, one-tailed), Physical Appearance (index group, M ¼ 13.2, Table 2 Mean scores on the CH-EDE subscales by group Index group Control group M (s.d.) M (s.d.) U Weight concern *** Shape concern *** Eating concern * Restraint ** *P < 0.05, **P < 0.01, ***P < s.d. ¼ 3.4; control group, M ¼ 18.2, s.d. ¼ 3.8; t ¼ 4.00, d.f. ¼ 34, P < 0.001, one-tailed), and Global Self-worth (index group, M ¼ 17.22, s.d. ¼ 3.9; control group, M ¼ 19.5, s.d. ¼ 2.6; t ¼ , d.f. ¼ 34, P < 0.05, one-tailed). The score for the SMFQ was significantly higher in the index group than in the control group (index group, M ¼ 6.1, s.d. ¼ 4.9; control group, M ¼ 3.7, s.d. ¼ 2.8; U ¼ 109, P < 0.05, one-tailed), using a Mann Whitney U-test. The relationships between the Weight, Shape, Eating and Global sub-scales of the CH-EDE, and the Harter Self-Perception Profile sub-scales and SMFQ scores are shown in Table 3, for the index group, using Spearman correlation coefficients. The significance level was set at 0.01, but correlations that reached the 0.05 level are also shown, for information, in Table 3. As can be seen from Table 3, there were significant negative correlations between each of the CH-EDE Concern sub-scales and Physical Appearance sub-scale of the Harter Self-Perception Profile. No other correlations were significant. The relationships between the Weight, Shape, Eating and Global sub-scales of the CH-EDE, and the Harter Self-Perception Profile sub-scales and SMFQ scores are shown in Table 4, for the control group, using Spearman correlation coefficients. No specific predictions had been made about the relationship between these variables in the control group, thus twotailed tests were used, together with a significance level of None of the correlations were significant at 0.01 (or 0.05) levels. Discussion Overweight girls had significantly higher scores than average-weight girls on the CH-EDE sub-scales for Weight, Shape and Eating Concern and Restraint. The overweight girls also had significantly lower ratings for self-esteem on three subscales of the Harter Self-Perception Profile: Athletic Competence, Physical Appearance and Global Self-worth, and just 1271 Table 3 Relationships between eating, weight and shape concerns, dietary restraint and self perception and symptoms of depression in the index group CH-EDE a Sub-scales Weight concern Shape concern Eating concern Dietary restraint Global concern Athletic competence b * * * Physical appearance b ** ** ** ** Behavioural conduct b Scholastic competence b Social acceptance b * Global self-worth b * SMFQ c * n ¼ 18. *P < 0.05; **P < 0.01, one-tailed. a CH-EDE, Child Eating Disorders Examination. b Harter Self-Perception Profile Sub-scales. c SMFQ ¼ Short Mood and Feelings Questionnaire.

5 1272 Table 4 Relationships between eating, weight and shape concerns, dietary restraint and self perception and symptoms of depression in the control group CH-EDE a Sub-scales Weight concern Shape concern Eating concern Dietary restraint Global concern Athletic competence b Physical appearance b Behavioural conduct b Scholastic competence b Social acceptance b Global self-worth b SMFQ c n ¼ 18. *P < 0.05; **P < 0.01, two-tailed. a CH-EDE, Child Eating Disorders Examination. b Harter Self-Perception Profile Sub-scales. c SMFQ ¼ Short Mood and Feelings Questionnaire. significantly higher scores for symptoms of depression, as assessed by the SMFQ, than the average-weight girls scores. As a group, overweight girls also showed some association between concerns about weight, shape and eating, and Physical Appearance self-esteem. These findings suggest that the overweight girls had more concerns about their weight, shape and eating and were attempting dietary restraint significantly more than the average weight girls. They also suggest that the overweight girls had somewhat lower self-esteem and more symptoms of depression than the average-weight girls. The nature of the relationship between the different features assessed suggests that, in overweight girls, increased concern about weight, shape and eating is associated with lower self-esteem related to physical appearance, but not necessarily with more symptoms of depression. Whilst these results lend some support to the hypotheses three methodological issues qualify the findings. Firstly, there was a significant difference in pubertal status between the two groups, as indicated by the number of girls in the index group who had reached menarche. Their comparative maturity may have influenced their attitudes towards their weight and shape, their self-esteem and report of depressive symptoms. Secondly, it is not clear from this study whether being overweight increases concerns, dietary restraint, low selfesteem and symptoms of depression or whether these concerns and symptoms increase the risk of becoming overweight. In either case, there is likely to be a complex relationship between these factors. For example, other factors might have a mediating role. One such factor might be the presence of specific eating or weight- and shape-related cognitions. Alternatively concerns and symptoms could be linked through relationship of these and overweight to a third factor. Family factors, such as parental emphasis on food and eating, weight and shape might be important here. Thirdly, it must be noted that the interviewer was aware of the hypotheses, which might have led to a recording bias. There was also a low response rate, which means that the sample studied may not be representative of the population from which they were drawn. Nevertheless, the findings lend some support to the suggestion that overweight girls may be at an increased risk of developing an eating disorder. Each of the factors investigated here has been identified as a risk factor for the later development of eating disorders. In addition, within the overweight group, specific (ie weight, shape and eating concerns) and general risk factors (ie physical appearance based self-esteem) covary, suggesting that some overweight girls may be particularly at risk. and shape, dietary restraint and self-esteem all have a key role in cognitive formulations of eating disorders. 32 Self-esteem based on weight and shape (one aspect of physical appearance) may be particularly important, indeed it is identified as a core feature of bulimia nervosa in DSM-IV. 6 The presence of features such as these in overweight children may explain how eating disorders might develop from childhood obesity. Further research is also needed. Ideally, a bigger sample is needed. It is possible that the relatively small sample size prevented some findings from reaching statistical significance. Several of the correlations between self-esteem subscales, depressive symptoms and eating, weight and shape concern sub-scales were relatively high, and associations were as predicted; several of these relationships would probably be significant if the sample were larger. A longitudinal study would enable us to tell whether the factors investigated here predict whether girls who are overweight develop eating disorders. Additional factors that may be protective or increase risk could also be investigated in such a study. This might include factors related to parents, peers and the media, and the extent to which girls have internalised socio-cultural values about weight and shape. The role of eating disorder specific cognitions could also be investigated in such a study. It would also be interesting to replicate this study with boys. There is evidence that a growing number of boys are

6 developing eating disorders. 33 Although it is not clear whether the issues and concerns are the same for boys and girls 34,17 being overweight is also a risk factor in boys. 35 Our results are clearly preliminary and warrant further investigation, preferably in longitudinal studies. Nevertheless, they suggest that overweight girls may be particularly at risk of developing later eating disorders. This is of particular concern given the growing prevalence of childhood obesity in both sexes. 35 References 1 Striegel-Moore RH, Silberstein L, Rodin J. Towards an understanding of risk factors for bulimia. Am Psychol 1986; 41: Fairburn CG, Welch SL, Doll HA, Davies BA, O Connor ME. Risk factors for bulimia nervosa: a community-based case control study. Arch Gen Psychiat 1997; 54: Fairburn CG, Doll HA, Welch SL, Hay PJ, Davies BA, O Connor, ME. Risk factors for binge eating disorder: a community-based, case control study. Arch Gen Psychiat 1998; 55: Garfinkel PE, Garner DM. 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