Background
Adolescence is a period of life when individuals transfer from childhood and their biological, cognitive, psychological, and social characteristics become more adult-like. The key developmental tasks of adolescence are the achievement of biological and sexual maturity, the development of personal identity, the development of intimate sexual relationships, and finally, the establishment of independence and autonomy [
1]. Adolescence is an intensive period in which the salience of body shape is considerable. New roles are negotiated in areas that are tied to physical appearance [
2,
3].
Overweight and obesity have become a global epidemic among adolescents of all ethnic and socioeconomic backgrounds. Excess weight is linked to diminished subjective well-being, including a poor quality of life [
4], body dissatisfaction [
5], low self-esteem [
6], poor academic performance [
7], depression [
8], high levels of sadness and anxiety [
9], and eating disorder pathology [
10]. Furthermore, overweight adolescents are described as socially marginalized; they are at greater risk of mistreatment by peers and have fewer opportunities to develop intimate romantic relationships [
11]. Research on adolescent community samples, however, has suggested that despite moderate levels of body dissatisfaction, relatively few adolescents with excess weight show low self-esteem or psychiatric comorbidity, or report poor emotional or social functioning [
12]. Furthermore, findings from a large community survey demonstrated no association of body mass index (BMI) with eating disorders [
13]. According to a follow-up community study by Roberts and Hao [
14], obesity has limited effects on the future psychosocial functioning of adolescents. The authors, for example, found no evidence that academic performance is negatively impacted by obesity.
Self-image, according to Offer et al. [
15], can be regarded as the organization of an individual’s perception of functioning and adjustment in different areas of his or her life. It is a multidimensional construct with different aspects described as the psychological, social, sexual, familial, and coping self. This reflects the necessity to evaluate adolescent functioning in multiple areas, because it is possible to master certain areas while having difficulties in others. In healthy youngsters, the change in self-image from early to mid-adolescence is generally positive [
16]. A negative self-image has been associated with many psychological problems such as low self-esteem [
17], problems at school [
18], depression [
19], and eating disorders [
20-
23], as well as with overweight and obesity [
24]. Concerning the components of self-image, overweight girls have been reported to be less adjusted with respect to their sexual attitudes and to present more psychopathology than their peers with average weight [
25]. Moreover, distortion of the body image has been linked to overweight and obesity [
26,
27]. According to a recent study by Farhat et al. [
28], body image mediated the relationship of obesity with infrequent breakfast consumption in both genders, but among girls also with smoking and a lack of physical activity. Furthermore, body image had a stronger association with victimization and bullying than objective BMI-derived weight classification [
29]. According to Roberts and Duong [
30], perceived weight rather than obesity increases the risk of major depression among adolescents.
Among adults, there is some evidence that subjective well-being variables influence success in weight loss [
31], and a greater focus on these variables both in obesity prevention and weight management programs has been demanded [
32]. Furthermore, among adolescents, emotional correlates of excess weight are important to assess in order to target individually appropriate interventions that could enhance well-being [
33]. One way to obtain more information on adjustment problems associated with overweight and obesity in adolescence is to study self-image and its development. The results might shed light on the important question of what types of psychosocial interventions should be included in weight management programs directed at adolescents. Previous self-image studies have hinted that problems might exist in the areas of psychological, sexual, and coping self among youngsters with excess weight, especially girls. However, as earlier research focusing on the psychosocial well-being of overweight and obese adolescents has been characterized by highly contradictory results, more research is needed, especially in the form of follow-up studies.
The aim of the present study was to investigate the development of self-image and its components during a one-year follow-up period among non-referred adolescents with excess and normal weight. Furthermore, as gender-specific differences exist in the self-image and its components [
34,
35], we separately analyzed the data for girls and boys.
Discussion
As far as we are aware, this is the first study to evaluate the development of self-image and its components in non-referred girls and boys with excess and normal weight in mid-adolescence. Most of the research focusing on self-image has been cross-sectional. Adolescence is a development period characterized by intense psychological, emotional, intellectual, and social maturation. This was also observed in our study, and focusing on the regression in OSIQ-R total scores, our finding is in accordance with an earlier study reporting that the change in self-image from early to mid-adolescence in normally developed adolescents is generally positive [
16].
For girls with normal weight, mid-adolescence appears to be a period characterized by a rapid development in self-image and its underlying components. Significant score changes compared to zero were observed in impulse control, social functioning, vocational attitudes, self-confidence, self-reliance, body image, sexuality, and ethical values. Among girls with excess weight, there was also a clear trend towards better adjustment, but none of the change scores compared to zero proved to be statistically significant. When the girls with normal and excess weight were compared, the difference in change scores was largest in sexuality and vocational attitudes. Recently, a study investigating self-image among girls in late adolescence with the OSIQ [
25] reported that overweight girls were less adjusted with regard to their sexual attitudes than their normal-weight peers. The development of sexual identity already starts to proceed, and intimate and romantic relationships to form in mid-adolescence [
2], and from this developmental perspective, our finding is not surprising. Interestingly, the finding is comparable to that reported in girls with severe underweight [
20,
21]. It appears that for girls, an abnormal weight and body shape easily provokes distress that associates with feelings, attitudes, and behavior towards the opposite sex. Our finding is also in line with earlier research reporting a link between adolescent obesity and problems in forming intimate relationships [
11]. Modern Western culture emphasizes thinness [
52], and adolescent girls are known to continually compare themselves with their peers, which may lead to severe frustration when a girl sees herself as significantly different from the others. Because of this, overweight girls may experience strong feelings of inadequacy [
25]. Furthermore, discriminatory attitudes and behaviors towards obese individuals in education and employment are a reality [
53]. This may all reflect in vocational attitudes, including the development of career plans, in girls with excess weight.
Change scores compared to zero were significant among boys with excess weight in sexuality and idealism, and among boys with normal weight in impulse control, mental health, self-reliance and sexuality. When the boys with excess and normal weight were compared, no statistically significant differences emerged in change scores. This finding could be interpreted so that among mid-adolescent boys, the development of self-image varies somewhat depending on the weight status, but is not substantially influenced by overweight and obesity.
One key area of psychological well-being is body image, i.e. the extent to which a person has adjusted to his or her body. There is evidence that obesity is linked to a poor body image, and treatments already exist to improve body image in overweight individuals. Both being female and an early age of onset of obesity have been recognized as risk factors for body image distortions [
52]. However, in a cross-sectional OSIQ-R study among normal and overweight girls in late adolescence [
25], the difference in body image was not statistically significant. In our study, among girls with normal weight, body image was one of the self-image components with significant change scores towards better adjustment. Among girls with excess weight, body image also showed a change score compared to zero, although this change was not statistically significant. Thus, although development towards better adjustment in body image was observed among these girls, this development was less intense.
From the clinical perspective, it appears that a greater focus on self-image may be indicated in obesity prevention and weight-management programs designed for adolescent populations. Girls with excess weight might particularly benefit from this. Moreover, sexuality, which is one of the key developmental tasks in adolescence [
1-
3], appears to be more problematic for overweight girls than their healthy peers.
There were some limitations as well as strengths in this follow-up study that need to be mentioned. Although the study involved as many as 24 secondary schools in the city of Helsinki, this represented only one-third of all secondary schools in the capital area. The overall participation rate in the schools was approximately 60%. A nationwide school survey carried out biannually in Finnish comprehensive schools (grades 8 and 9) with the same data collection method has repeatedly reported a participation rate of approximately 80% [
54]. Consequently, although the participation rate of the present study cannot be regarded as excellent, it can be considered acceptable. The prevalence of overweight and obesity in adolescence has been reported to vary between 10% and 20% in most European countries [
55,
56], and consistently with this it was approximately 13% in the present study. An obvious weakness was the limited number of participants with a relative weight of 26% or more above the median. However, a clear strength is that the BMI values were calculated from measurements taken by professional school nurses, since self-reported data are known to underestimate the prevalence of overweight [
57]. Nevertheless, those adolescents with the most marked weight problems might have refused to participate in the study because of this methodology. The dropout group consisted of 10 adolescents. The drop-outs in the control group showed more negative self-image than those who attended the whole study, and the drop-outs with excess weight exhibited higher relative weights than those who participated the whole study. However, the impact of the dropouts was very small and did not alter the results or their implications. Sufficient internal consistencies of the components of the OSIQ have been confirmed, except for those components focusing on ethical values and idealism [
37,
41,
58]. In the present study, these same components as well as the self-reliance scale, showed low reliability. Therefore, the results of these three scales must be interpreted with caution. Studies with longer follow-up times are clearly needed in the future.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
MM participated in the design of the study, collected and analyzed the data, and served as the first author. MM participated in the writing process. EK designed and performed the statistical analyses. VT designed and drew the graphics. L-R P-V and VA participated in the design of the study. NL participated in the writing process. All authors read and approved the final manuscript.