Anorexia nervosa and bulimia: a prevalence study de Azevedo MHP, Ferreira CP. Anorexia nervosa and bulimia: a prevalence study. Acta Psychiatr Scand 1992: 86: 432-436. We determined the prevalence of anorexia nervosa and bulimia in a large sample of students attending a secondary school on the island of S%oMiguel (Azores) using the Diagnostic Interview for Children and Adolescents, which enabled us to collect the information necessary to make DSM-I11 diagnoses. Although the prevalence of anorectic and bulimic behaviour was rather high, the partial syndrome of anorexia nervosa was found in only 0.48% of the students (0.76% for girls and 0.17% for boys) and the syndrome of bulimia in only 0.16% (0.30% of the girls; there were no boys with bulimia). The overall prevalence of eating disorders, including partial syndromes, was rather low (0.64%). These results stand in sharp contrast to reports that eating disorders are common and probably getting more common. The low prevalence found in the present survey is probably due to the absence of sociocultural pressures to control eating and weight.
Eating disorders are considered major health problems for wealthy and more industrialized societies. In recent years, concern has been expressed about the rising prevalence of anorexia nervosa and bulimia (1-3). The apparent increase in these two conditions has been referred to by some as alarming (4) and others have described it as reaching epidemic proportions ( 5 , 6 ) . In 1979, a specialist in psychiatry came to live and practice in Silo Miguel (Azores) and a psychiatric service has been developed that embraces the whole island (prior to 1979 there were no psychiatrists resident and practising on the island). However, no cases of either anorexia nervosa or bulimia were seen over the next decade (7). In view of this information, we planned a survey of the prevalence of anorexia nervosa and bulimia in a secondary school population. To the authors’ knowledge, this is the first report of a prevalence study of such disorders undertaken either in the Azores or mainland Portugal. Material and methods Study population
The population included in this study were students of both sexes, from grade 7 to 12, enrolled in one state secondary school in the town of Ponta Delgada, SZo Miguel Island, Azores (an autonomous region of Portugal). The Azores - comprising 3 groups of islands - lie in the Atlantic, 1220 km from Lisbon and 3400 km from New York. Silo Miguel, 432
M. H. P. de Azevedo, C. P. Ferreira Department of Medical Psychology and Department of Psychiatry, Faculty of Medicine, Coimbra, Portugal
Key words: anorexia nervosa; bulimia; epidemiology Maria Helena Pinto de Azevedo, M.D., Psicologia Medica. Faculdade de Medicina, 3049 Coimbra Codex, Portugal Accepted for publication August 1, 1992
forming part of the eastern group, is the largest and most populous island in the archipelago. The school chosen for the study is situated in the western part of the town, bordering on one of the most populous areas of the island. The people’s main sources of livelihood are farming and cattlerearing. In the Autonomous Region of the Azores there is no social classification of the population. In this investigation the social grouping of the students according to social background (or social class) was based on the father’s occupational status and level of education (8). The interview schedule
The section on eating disorders of the Diagnostic Interview for Children and Adolescents (DICA) was used to collect the information necessary to make the diagnoses of anorexia nervosa and bulimia as defined by DSM-I11 (9). The items constituting the eating disorders section/ DICA were translated into Portuguese by one of us (M.H.P.A.), compared with a back-translation carried out by a professional translator and reviewed by a bilingual university teacher of languages. Then, the final translation was administered to psychiatric patients and normals and proved to be well understood and responded to. For the few patients with eating disorders, at the time of interview, all DICA diagnoses agreed with the clinical diagnoses made by the psychiatrists who cared for the patient. All questions
Anorexia nervosa and bulimia
(except those for weight and height variables) are presented in a yes/no response format. A yes response is scored 2 and a no response is scored 1. Answers are coded as the interview is given. Disorders are assessed as ever being present during the subject’s lifetime (yielding a lifetime prevalence rate). The DICA is a highly structured questionnaire (1013). It was designed to give a comprehensive clinical assessment of a school child or adolescent. Demographic information such as sex, race, age, grade in school, parents’ occupation and level of education was also collected. The interviews were conducted by last-year (3rd) nursing students (a team of 16 women) after finishing the training course (3 months) on psychiatry and mental health. Prior to the commencement of the study, they were given brief instructions about administering and recording the interview and practised using it during one week. At the end of the training period, the nursing students were asked to interview separately the same pupil of a group of 10 recruited from a different school. Interrater agreement was calculated, item by item, as the percentage agreement on the items scoring. Overall, there was an excellent measure of agreement between raters. The range of agreement on individual items was 71.4-100% with a mean rate of 98.9%. Procedure
With the approval of the Regional Secretary of Education and permission granted by the director of the school concerned, all teachers were willing to help us in approaching the study population. The field work was carried out during one week at the end of the school year (June 1987). During this period, all students attending the classes were invited by their teachers to participate in an investigation about eating behaviour. Of those approached, all but one (a girl) agreed to be interviewed. The students were interviewed individually in a room on school premises during school hours. Not all students were present (absentees and dropouts) during the period interviewing was undertaken, so that only attenders were interviewed. This resulted in a total sample of 1234 of 1718 pupils enrolled at the beginning of the academic year (September 1986). We were informed that 198 students had left school (1 19 cancelled the enrolment and 79 missed the school year through truancy) and 18.7% (285) were absent from school, a rate of absenteeism considered normal, given that the field work was carried out during the last school term and the fact that coincided with the Festival of Our Lord Christ, the most important in the island. The statistical analysis was performed by using the SYSTAT, version 3.0 (14).
Results
Characteristics of the sample
The sample consisted of 1234 students. The demographic characteristics are shown in Table 1. A majority of the students were girls; almost half were in the 15-17 age group; the mean age was 15.7 (SD = 2.1). The great majority of the students were in grades 7-10. All were white and predominantly from middle-lower social backgrounds (so(75 cial classes 111 and IV), as indicated by the father’s occupation and level of education.
x)
Prevalence
Only 2 cases were found to fulfil all diagnostic criteria for an eating disorder as defined by DSM-111: 2 girls who met all criteria for bulimia. Six students ( 5 girls and 1 boy) showed a partial syndrome of anorexia nervosa, in that they fulfilled all diagnostic criteria for the disorder, except weight criterion. Because of these small numbers it was not possible to determine the distribution of the disorders by demographic factors. Frequency of anorectic and bulimia behaviour
The affirmative responses given to certain questions on the eating interview were examined to obtain an estimate of the prevalence of some anorectic and bulimic behaviours. Table2 lists the prevalence by sex of some anorectic behaviours. Of the 1234 students interviewed, 26 % reported ever having lost weight by dieting (ever dieted). Dieting was significantly more frequent in girls than in boys (31% vs 19%). The combination “ever dieted” and each one of Table 1. Characteristics of the sample (n= 1234)
Sex Female Male
654 580
53 47
39 1 599 244
32 49 20
9-10 11-12
508 519 207
41 42 17
Social class I II 111 IV
85 216 529 404
7 18 43 33
Age (years)
12-14 15-17 18-20 Grade 7-8
433
de Azevedo & Ferreira Table 2. Anorectic behaviours among students Girls
Boys
%
n
204
Ever dieted Positive for 'ever dieted' plus: Thoughts about overweight Fear of being fat Disturbance of body image
31
29 27 22
Total
n
%
n
113
19
317
4.5 4.2 3.4
2.1 1.9 1.6
12 11 9
the other anorectic behaviours are much less frequent (Table 2). Thus, 3.3% reported dieting plus thoughts about overweight (thought they were too fat); 3.0% dieting plus fear of being fat (afraid of becoming too fat) and 2.5% with the combination dieting plus disturbance of body image (thought the body or some parts of the body were still too fat, even though other people thought he or she was too thin). With regard to these combinations of anorectic behaviours, no significant differences were found between boys and girls. Table 3 shows the distribution of some bulimic behaviours by sex. The experience of ever having eating binges (episodes of eating much larger amounts of food than usual all at a time) was reported by 45% of the students, and 40% reported eating binges of high-calorie foods (consumption of highcalorie foods, such as cakes, sweets and bread, during binges). High-calorie eating binges were significantly more frequent in boys than in girls (40% vs 29% 1. The combination of high-calorie binges plus binge discomfort (pains in stomach that could self-induce the vomit to get rid of the excess food); high-calorie binges plus inability to stop eating (fear of not being able to stop eating); high-calorie binges plus hidden binges (tried to hide from other people the fact that they were eating so much); high-calorie binges plus attempts to lose weight (tried to lose weight by strict
%
26
41 38 31
3.3 3.0 2.5
x2
P
22.1
Eating disorders are considered major health problems for wealthy and more industrialized societies. In recent years, concern has been expressed about the rising prevalence of anorexia nervosa and bulimia (1-3). The apparent increase in these two conditions has been referred to by some as alarming (4) and others have described it as reaching epidemic proportions ( 5 , 6 ) . In 1979, a specialist in psychiatry came to live and practice in Silo Miguel (Azores) and a psychiatric service has been developed that embraces the whole island (prior to 1979 there were no psychiatrists resident and practising on the island). However, no cases of either anorexia nervosa or bulimia were seen over the next decade (7). In view of this information, we planned a survey of the prevalence of anorexia nervosa and bulimia in a secondary school population. To the authors’ knowledge, this is the first report of a prevalence study of such disorders undertaken either in the Azores or mainland Portugal. Material and methods Study population
The population included in this study were students of both sexes, from grade 7 to 12, enrolled in one state secondary school in the town of Ponta Delgada, SZo Miguel Island, Azores (an autonomous region of Portugal). The Azores - comprising 3 groups of islands - lie in the Atlantic, 1220 km from Lisbon and 3400 km from New York. Silo Miguel, 432
M. H. P. de Azevedo, C. P. Ferreira Department of Medical Psychology and Department of Psychiatry, Faculty of Medicine, Coimbra, Portugal
Key words: anorexia nervosa; bulimia; epidemiology Maria Helena Pinto de Azevedo, M.D., Psicologia Medica. Faculdade de Medicina, 3049 Coimbra Codex, Portugal Accepted for publication August 1, 1992
forming part of the eastern group, is the largest and most populous island in the archipelago. The school chosen for the study is situated in the western part of the town, bordering on one of the most populous areas of the island. The people’s main sources of livelihood are farming and cattlerearing. In the Autonomous Region of the Azores there is no social classification of the population. In this investigation the social grouping of the students according to social background (or social class) was based on the father’s occupational status and level of education (8). The interview schedule
The section on eating disorders of the Diagnostic Interview for Children and Adolescents (DICA) was used to collect the information necessary to make the diagnoses of anorexia nervosa and bulimia as defined by DSM-I11 (9). The items constituting the eating disorders section/ DICA were translated into Portuguese by one of us (M.H.P.A.), compared with a back-translation carried out by a professional translator and reviewed by a bilingual university teacher of languages. Then, the final translation was administered to psychiatric patients and normals and proved to be well understood and responded to. For the few patients with eating disorders, at the time of interview, all DICA diagnoses agreed with the clinical diagnoses made by the psychiatrists who cared for the patient. All questions
Anorexia nervosa and bulimia
(except those for weight and height variables) are presented in a yes/no response format. A yes response is scored 2 and a no response is scored 1. Answers are coded as the interview is given. Disorders are assessed as ever being present during the subject’s lifetime (yielding a lifetime prevalence rate). The DICA is a highly structured questionnaire (1013). It was designed to give a comprehensive clinical assessment of a school child or adolescent. Demographic information such as sex, race, age, grade in school, parents’ occupation and level of education was also collected. The interviews were conducted by last-year (3rd) nursing students (a team of 16 women) after finishing the training course (3 months) on psychiatry and mental health. Prior to the commencement of the study, they were given brief instructions about administering and recording the interview and practised using it during one week. At the end of the training period, the nursing students were asked to interview separately the same pupil of a group of 10 recruited from a different school. Interrater agreement was calculated, item by item, as the percentage agreement on the items scoring. Overall, there was an excellent measure of agreement between raters. The range of agreement on individual items was 71.4-100% with a mean rate of 98.9%. Procedure
With the approval of the Regional Secretary of Education and permission granted by the director of the school concerned, all teachers were willing to help us in approaching the study population. The field work was carried out during one week at the end of the school year (June 1987). During this period, all students attending the classes were invited by their teachers to participate in an investigation about eating behaviour. Of those approached, all but one (a girl) agreed to be interviewed. The students were interviewed individually in a room on school premises during school hours. Not all students were present (absentees and dropouts) during the period interviewing was undertaken, so that only attenders were interviewed. This resulted in a total sample of 1234 of 1718 pupils enrolled at the beginning of the academic year (September 1986). We were informed that 198 students had left school (1 19 cancelled the enrolment and 79 missed the school year through truancy) and 18.7% (285) were absent from school, a rate of absenteeism considered normal, given that the field work was carried out during the last school term and the fact that coincided with the Festival of Our Lord Christ, the most important in the island. The statistical analysis was performed by using the SYSTAT, version 3.0 (14).
Results
Characteristics of the sample
The sample consisted of 1234 students. The demographic characteristics are shown in Table 1. A majority of the students were girls; almost half were in the 15-17 age group; the mean age was 15.7 (SD = 2.1). The great majority of the students were in grades 7-10. All were white and predominantly from middle-lower social backgrounds (so(75 cial classes 111 and IV), as indicated by the father’s occupation and level of education.
x)
Prevalence
Only 2 cases were found to fulfil all diagnostic criteria for an eating disorder as defined by DSM-111: 2 girls who met all criteria for bulimia. Six students ( 5 girls and 1 boy) showed a partial syndrome of anorexia nervosa, in that they fulfilled all diagnostic criteria for the disorder, except weight criterion. Because of these small numbers it was not possible to determine the distribution of the disorders by demographic factors. Frequency of anorectic and bulimia behaviour
The affirmative responses given to certain questions on the eating interview were examined to obtain an estimate of the prevalence of some anorectic and bulimic behaviours. Table2 lists the prevalence by sex of some anorectic behaviours. Of the 1234 students interviewed, 26 % reported ever having lost weight by dieting (ever dieted). Dieting was significantly more frequent in girls than in boys (31% vs 19%). The combination “ever dieted” and each one of Table 1. Characteristics of the sample (n= 1234)
Sex Female Male
654 580
53 47
39 1 599 244
32 49 20
9-10 11-12
508 519 207
41 42 17
Social class I II 111 IV
85 216 529 404
7 18 43 33
Age (years)
12-14 15-17 18-20 Grade 7-8
433
de Azevedo & Ferreira Table 2. Anorectic behaviours among students Girls
Boys
%
n
204
Ever dieted Positive for 'ever dieted' plus: Thoughts about overweight Fear of being fat Disturbance of body image
31
29 27 22
Total
n
%
n
113
19
317
4.5 4.2 3.4
2.1 1.9 1.6
12 11 9
the other anorectic behaviours are much less frequent (Table 2). Thus, 3.3% reported dieting plus thoughts about overweight (thought they were too fat); 3.0% dieting plus fear of being fat (afraid of becoming too fat) and 2.5% with the combination dieting plus disturbance of body image (thought the body or some parts of the body were still too fat, even though other people thought he or she was too thin). With regard to these combinations of anorectic behaviours, no significant differences were found between boys and girls. Table 3 shows the distribution of some bulimic behaviours by sex. The experience of ever having eating binges (episodes of eating much larger amounts of food than usual all at a time) was reported by 45% of the students, and 40% reported eating binges of high-calorie foods (consumption of highcalorie foods, such as cakes, sweets and bread, during binges). High-calorie eating binges were significantly more frequent in boys than in girls (40% vs 29% 1. The combination of high-calorie binges plus binge discomfort (pains in stomach that could self-induce the vomit to get rid of the excess food); high-calorie binges plus inability to stop eating (fear of not being able to stop eating); high-calorie binges plus hidden binges (tried to hide from other people the fact that they were eating so much); high-calorie binges plus attempts to lose weight (tried to lose weight by strict
%
26
41 38 31
3.3 3.0 2.5
x2
P
22.1
