Psychosocial consequences of weight screening of school-age children – a systematic review

Routine weighing of children is an ingrained part of preventive child health programmes in many countries. When most weight-screening programmes were originally introduced, they targeted malnutrition and underweight. Today, physical diseases are rare among children in most developed modern societies.

A high BMI in children and adolescents is a risk factor for a high BMI later in life and for disease. In children and adolescents, a high BMI is associated with low self-esteem [1], body image dissatisfaction [2] and bullying [3], social marginalisation and stigmatisation [4] in school and at home [1]. Weight-based teasing in adolescence affects emotional well-being [5] and has been associated with disordered eating behaviours and an increased risk of weight gain later in life [6, 7].

It is convenient to assume that the solution is managing weight in childhood. However, the evidence in the field indicates that weighing children does not lead to a reduced BMI [8, 9]. Many normal-weight adolescents misperceive themselves as overweight [10]. Project EAT, a population-based study with nearly 5,000 teenagers, found that more than half of the girls and one third of the boys displayed unhealthy weight control behaviours [11]. The relationship between perceived body weight and a wide range of negative mental health outcomes has been demonstrated in numerous studies [1, 2, 10, 12-14]. Several studies advocate that recommendations for weight monitoring should be made cautiously and avoid messages that may potentially encourage weight control behaviour such as frequent self-weighing [15, 16].

In screening programmes, health benefits should outweigh potential harm [17]. The potential harm of routine weighing of children has not been explored systematically, and the psychosocial consequences of weighing children remain uncertain. Thus, the overall health effects of a weight-screening programme in a developed modern society are unknown.

This paper aimed to review the existing literature on psychosocial consequences of routine weighing of school-aged children and providing subsequent weight feedback.

METHODS

This systematic review follows the PRISMA guideline [18]. To enhance transparency when synthesising and reporting the qualitative research, we adopted the Enhancing Transparency in Reporting the Synthesis of Qualitative Research (ENTREQ) standards [19].

Search strategy and sources

A search strategy was developed with assistance from a specialist librarian. A comprehensive systematic literature search strategy was followed, using a modified PICO format and applying an expansive list of possibly relevant keywords and synonyms related to the terms ‘routine weighing’ and ‘psychosocial consequences’. The PICO parameters were population (children and adolescents, aged 6-18, in high-income countries), intervention (routine weighing or BMI screening and reporting to parents, done by a professional, e.g., teacher or school nurse, without specific medical indication) and outcome (psychological and social outcomes after weighing or reporting weight). The searches were run on 5 May 2022 in the following databases: PubMed, PsycINFO, Sociological Abstracts and CINAHL. See this supplementary file for the full search strategy. Furthermore, the reference lists of all included studies were searched manually.

Study selection

Two authors (JJ and GO) screened titles and abstracts independently [20]. Duplicates and retracted studies were removed electronically. The Covidence Systematic Review Software [21] was used to screen and select studies for full-text reading and inclusion. Selected articles were reviewed individually, and all authors agreed on which articles to include in the review.

Inclusion and exclusion criteria

The studies had to be original, peer-reviewed and reported in English. They were required to report experiences or consequences connected to the act of weighing with no specific medical indication. Studies were excluded if they did not examine psychosocial outcomes, examined parents’ reactions to BMI feedback without including the children’s view or examined consequences related to self-weighing.

Quality assessment

We followed the Equator Network’s guidelines on enhancing the transparency of health research. The quality of the included studies was assessed by all authors, using checklists. STROBE was used for the observational studies, CONSORT for randomised clinical studies and COREQ for qualitative research [22]. Cases of doubt were discussed and resolved by all authors. No studies were excluded based on the quality assessment.

Data extraction and synthesis of results

The extracted data included study characteristics, data collection, population, outcome measures and results relevant to the research question. The findings were coded and the results were summarised in categories considering the nature of the effect on psychosocial outcomes (Table 1). From this table, we were able to identify themes to make a qualitative analysis of the study results.

RESULTS

A total of 1,193 records were identified. After removal of duplicates, 1,122 titles and abstracts were screened. Twenty-two full-text articles were assessed for eligibility and six studies included for review (Figure 1).

Table 2 presents the characteristics of the studies. Five studies collected data with questionnaires [8, 23-26]. Among these, three studies gathered information about adverse outcomes [8, 23, 24]. They collected data before the weighing and at varying follow-ups after weight feedback. Two of the five studies reported the children’s level of comfort with their weight feedback as the only measure relevant to our aim at one month after BMI feedback [25, 26]. Nnyanzi collected data with semi-structured interviews after weight feedback [27]. None of the included studies described psychosocial consequences of routine weight-screening specifically among children with a low BMI.

Psychosocial outcomes

Table 1 displays the recorded effects of weighing and weight feedback on psychosocial outcomes. The reported consequences varied across the studies, e.g., from 96% of the children being comfortable with the process [24] and 68% being “not at all uncomfortable” [26], to 70% being uncomfortable with receiving and discussing BMI feedback [25]. Falconer et al. [23] found no ‘apparent’ positive or negative effects of weighing and providing feedback on weight-related teasing or self-esteem. Three studies reported positive effects on psychosocial outcomes [8, 24, 27] and four studies found negative effects on psychosocial outcomes [8, 24, 26, 27].

Positive effects

Nnyanzi [27] found that some children were curious and positive about taking part in the weighing. However, the study stated that this kind of enthusiasm was typical for children who perceived themselves to be of ideal weight. The weighing process would also be experienced as a welcomed opportunity to talk about health, and as a relief after the weighing when they discovered that other children were not told of their weight:

“It was OK because other children didn’t know what your weight was so they couldn’t talk about it” [24].

Body self-esteem, relief and joy were found to increase after being weighed in children categorised as of normal weight [24, 27]. Madsen et al. [8] found that, after one year, adverse weight control behaviours had declined more among students who were BMI screened at school than among controls who were not BMI screened. Grimmett et al. [24] observed no change in eating behaviour or weight-related teasing after weight feedback.

Negative effects

Weight satisfaction declined and peer weight talk increased independently of weight status in children taking part in the two-year randomised BMI screening programme described by Madsen et al. [8]. Nnyanzi observed a growing preoccupation with body weight in all weight categories. However, this was more pronounced among children who perceived themselves to have weight problems [27]. Children who were told that they were overweight were often surprised about this and reacted with denial or shock. In Kaczmarski et al.’s study [25], nearly 70% of the children felt discomfort during the weight feedback, and Kubik et al. [26] reported that overweight children felt discomfort when receiving weight feedback. However, these studies did not further explore this discomfort. Grimmett et al. [24] found that only few children disliked the process of weighing, stating that they did not want anyone to know their weight and that they perceived weighing a “perfect opportunity” for weight-teasing. Some children expressed that emotional distress was associated with the process of weighing and being given feedback:

“… I just felt oh, when am I gonna get this letter to see what height and weight I am and I was just quite nerve rackened” [27].

The reactions on weight feedback were often emotional, and some children expressed that they did not know what to do about the information given and had to rely on the adults around them to tackle their weight issues, which caused additional worry.

DISCUSSION

Our systematic synthesis of the literature indicated that routine weighing and weight feedback in school-aged children may have harmful psychosocial consequences for some children. Negative consequences included decreased weight satisfaction, increased weight focus and frequency of peer weight talk, over-sensitisation about weight and emotional distress and discomfort associated with the process. Our results relate to the findings of Ikeda et al. who among other topics addressed body dissatisfaction and lowered self-esteem as potential harms of BMI screening [28]. Our review suggested that harmful psychosocial consequences were frequent in children with a high BMI, whereas normal-weight children seemed to have mainly positive or neutral experiences with weighing and receiving feedback.

The review also points to a scarcity of evidence about the psychosocial consequences of weight-screening children, which is a common practice in many countries.

The most comprehensive and relevant study regarding the research question was conducted by Madsen et al. [8]. This study explored the impact of school-based BMI screening and subsequent BMI reports on anticipated adverse effects. It was a well-powered randomised clinical trial that explored multiple aspects of adverse effects and had three years of follow-up. Multiple aspects of psychosocial outcomes were examined in [8, 23, 24, 27]. Three of these studies [8, 24, 27] had children reporting for themselves, limiting the potential bias of adult interpretation of the children’s emotions.

However, the design of two studies did not allow for analyses stratified on BMI categories (as children in the control arm were not weighed), which is a limitation as other included studies primarily found negative psychosocial consequences of routine weighing among children with a high BMI [26, 27]. Two studies [25, 26] did not aim to explore the consequences of weighing and providing weight feedback. However, both studies reported on the comfort of children discussing BMI feedback letters with their parents. Thus, the study design did not allow us to conclude whether the reported impact was related to the BMI assessment, BMI feedback and/or weight discussion. Both studies [25, 26] were at risk of selection bias in terms of which parents chose to take the discussion with their children. Furthermore, parents reported on behalf of their children in the studies by Kaczmarski et al. [25], Kubik et al. [26] and Falconer et al. [23], which carries a risk of proxy response bias.

Falconer et al. [23] conducted a large cohort study exploring two psychosocial outcomes. Unfortunately, the study had a low response rate of only 18.9%, a high attrition rate and underrepresentation of children with a high BMI, all of which limits the generalisability of the study. The resulting selection bias may therefore well explain the null findings reported. In line with this, three studies had strong selection bias with an underrepresentation of overweight children [24] and an overrepresentation of highly educated Caucasian parents [24-26]. In contrast, the study by Nnyanzi [27] had an overrepresentation of children from areas of high deprivation (61.9%). All studies failed to declare conflicts of interest, except for the study by Falconer et al. [23] where one author was a director at Public Health England and thus responsible for the weight-screening programme examined.

This review included all studies we could identify that were relevant to our research question. A comprehensive literature search was performed in four major databases with assistance from a specialist librarian. It is a strength that our synthesis displays the scope of all the available evidence on the topic. The review was conducted adopting the PRISMA standards [18], and the included studies were systematically assessed for quality.

Among the six included studies, three were conducted in local school districts in England and three in the USA. These conditions make their results applicable to societies that resemble these countries but limit the generalisability to other societies.

The six included studies were heterogeneous regarding aim, design and outcome measures. Some studies were methodically limited by employing a simple assessment method of psychosocial consequences. Considering that our systematic review included all available evidence related to our research question, this clearly displays a gap in the literature; little evidence of good quality exists in the field.

Future research into the psychosocial consequences of weight-screening should explore these consequences among children and adolescents themselves and not by parent proxies. It would be valuable to differentiate between the weighing process itself and provision of weight feedback to parents to establish which intervention is related to which outcome.

In context of the increasingly poor mental health among children and adolescents in many countries, authorities and professionals should pay attention to the side effects of existing practices. Weight-screening of children should apply to Wilson and Junger’s principles like all other screening programmes [17]. As there is no documented long-term effect of dieting or weight loss interventions among children, the current screening programme identifying overweight children conflicts with the screening ethics principles. In addition, the present review points to the existence of psychosocial harms related to the screening process.

CONCLUSIONS

This systematic review found that routine weighing of school-age children and subsequent provision of weight feedback may result in harmful psychosocial consequences such as an increased weight focus and frequency of peer weight talk, decreased weight satisfaction and general over-sensitisation about weight. The unfavourable effects primarily seemed to affect children categorised as overweight, whereas children categorised as normal weight seemed to have positive or neutral experiences with weighing and receiving feedback.

A literature gap exists as investigating adverse effects of weight-screening programmes among children and adolescents is scarce, and more studies are warranted. Weight screening does not prevent weight gain but has the potential to harm mental health. Preventive weight-screening programmes in children should follow general ethical principles for screening and should be evaluated regarding their overall impact, including any effects on physical, psychological and social health.