A total of 188 young adult women took part in the study (age: M = 25.58; SD = 2.90; min = 19, max = 30); we chose a young study group on purpose, as this is a developmental period in which body image is very important and assessments thereof are the most critical (19). We selected two groups of women who have conditions that affect how one looks: obesity and psoriasis. Despite the fact that these conditions often co-occur (62), we focused on groups of women with only obesity [as per WHO BMI ≥ 30, n = 54; (61)] or psoriasis (the inclusion criteria were at least 1 year having elapsed since diagnosis and visible skin lesions; n = 57). In order to assess whether the investigated phenomena occur only for the group with the visible stigmatising conditions, women with normal weight and no skin conditions were also included in the study (control group; n = 77). None of the study participants underwent bariatric surgery or laser skin therapy.

The recruitment procedure had two stages. During the first stage, females participating in a larger project, described elsewhere (63), who met the inclusion criteria for this study were recruited. During the second stage, females who met the inclusion criteria for this research project were asked to invite acquaintances to participate—i.e. a non-random method of sample selection [“snowball sampling technique”; (64)]. A total sample of 188 females was recruited for this study. Data were collected between 2018 and 2019.

Participants completed the following questionnaires: the Perceived Stigmatisation Questionnaire, the Multidimensional Body-Self Relations Questionnaire, and a short survey to collect medical and sociodemographic variables. These questionnaires were completed during a visit to a dietician, dermatologist, or psychologist, or at home (in this case, participants had 2 weeks to complete the questionnaires). Additionally, we collected objective body measurements: body mass, height, and sizes of individual body parts. This allowed us to calculate anthropometric indices for all participants, such as Body Mass Index (BMI), Index Of Central Obesity (ICO), and Waist-to-Hip Ratio (WHR). Moreover, the objective body parameters connected with body mass were controlled using a body composition analyzer. The data used for this study were part of a larger survey and the questionnaires that formed this study took around 25 min to complete.

The protocol of this study was approved by the Ethics Board for Research Projects at the Institute of Psychology, University of Gdansk, Poland (decision no. 12/2018).

The analyses were performed in Python 3.8.5 programming language (Python Software Foundation, USA, 512 Lafayette Boulevard, Suite 2, Fredericksburg, Virginia 22401) programming language, using JupiterLab 2.2.6(Open Source Software) as the computation environment.

The following python libraries were used:

pandas 1.1.3 (Open Source Software);

Test data were contained in pandas.DataFrame. DataFrame is a two-dimensional, size-mutable, potentially heterogeneous tabular data type. Its structure contains labelled axes (rows and columns). Arithmetic operations align on both row and column labels. It can be considered a mathematical database. This study used DataFrame to index and align data. Each row contained all data collected from a single participant.

Wilk-Shapiro test was performed using scipy.stats.shapiro function. One way Anova test was performed using pingouin.anova function. Kurskal test was performed using scipy.stats.kruskal. Spearman's Rho correlations were calculated using scipy.stats.spearmanr function. Pearson's Rho correlations were calculated using scipy.stats.pearsonr function. Z-Score was calculated by executing pandas.DataFrame.apply(numpy.mstats.zscore). Moderation was calculated using python implementation of prof. Hayes, A. F. PROCESS macro. Wilk-Shapiro test was used to verify parametric assumptions on data used in the document.

As a result, non-parametric variables were found: Absence of Friendly Behaviour, Appearance Orientation (AO), Fitness Orientation (FO), Health Orientation (HO), Illness Orientation (IO).

For parametric variables, the validity of group selection was determined by using mean analysis, ANOVA, and Dunn's multiple comparison test. For non-parametric variables, the validity of group selection was determined by using mean analysis, Kruskal-Wallis H-test, and Tukey's range test.

Pearson Rho correlation ware calculated for parametric variables, between groups for Anthropometric Indices, PSQ, and MBSRQ while Spearman Rho correlations were calculated for non-parametric variables.

Bias-correct, no-nparametric, bootstrap PROCESS MACRO moderation was used to determine the relationship of Anthropometric Indices, and PSQ with MBSRQ as relation moderator.

First, we assessed whether groups had been selected appropriately. Their characteristics and anthropometric differences are presented in Table 1.

The collected data indicate that the groups were selected appropriately. The groups differed in terms of the parameters that were key to the sampling process. Parameters regarding body mass and BMI were the highest in the group of women affected with obesity (Dunn post hoc analysis: p < 0.001), while those regarding the phase and the severity of disease were highest in the group affected by psoriasis (p < 0.001). The groups did not differ in terms of age and height.

Attitudes towards one's own body differed between the groups (Table 2).

Women affected by obesity had the lowest satisfaction with their bodies (Tukey comparison with psoriasis: p > 0.002; and the control group: p = 0.001) and the lowest assessment of their looks (Dunn post hoc analysis: p > 0.001). It is not surprising that this was associated with the assessment of one's body mass (post hoc Tukey: p > 0.001) and with being preoccupied with one's weight as an aspect of the assessment of one's appearance (Dunn post hoc analysis: p < 0.001). Health, understood as an aspect of one's attitude one's own body, was assessed the highest by women with psoriasis (post hoc Tukey: p = 0.01).

Some statistically significant differences were also observed for perceived stigma (Table 3).

Overall sense of stigma was greater in women affected by obesity than those affected by psoriasis (p = 0.012) or the control group (p = 0.044). Further analyses did not reveal any differences between women with psoriasis and women from the control group (p = 0.493).

In the next step, we investigated the relationships of anthropometric indices and body dimension with perceived stigma. There was a surprising lack of relationship between perceived stigma and objective indices regarding body shape (WHR, ICO) as well as the severity of psoriasis (Disease Severity). However, there were correlations between sense of stigma and parameters associated with body mass and fat levels (Table 4). The greatest number of significant correlations were observed in the group of women affected by obesity. Interestingly, significant relationships revealed in the psoriasis group were negative, which means that the higher one's body mass, the lesser the perceived stigma (provided one does not reach the threshold of being overweight).

Moderation analysis was performed in order to investigate the role of subjective assessment of one's body in the relation between objective body measurements and perceived stigma (Figure 1).

No moderation effect was observed in the relation between objective indices regarding body shape (WHR and ICO) as well as the severity of psoriasis (Disease Severity) and perceived stigma. Health Evaluation was the most common moderator associated with the subjective attitude towards one's own body in the relationship between body dimensions (body mass, %BF, and visceral fat) and perceived stigma. It is worth noting that this was the only moderating factor in the group of women with psoriasis, while it did not moderate any of the relationships in the case of women with obesity. Interestingly, in the group of women affected with obesity, attitude towards one's own body significantly influenced the sense of being stared at and the experience of hostile behaviours in social relations when body mass or body fat levels were higher.

We hypothesised that the level of perceived stigma would depend on the type of stigma. The fact of being chronically ill itself, irrespective of the type of illness, results in stigma (73). However, our study found that not every illness leads to the same levels of perceived stigma. In line with the hypotheses, obese women were more likely to have a sense of stigma than women in other groups. This agrees with our previous results: a study on a smaller number of women (11) found that obese women were more likely to experience hostility as part of their stigma than women with skin conditions or those without an objective stigma. Lin et al. (74) asked 464 teenagers who were either overweight or non-obese about depressive symptoms, perceived stigma associated with body mass, and internalised stigma; they also measured actual and perceived weight status. They concluded that weight-related self-stigma is a problem even for people who are not overweight, because perceived weight stigma was associated with weight-related self-stigma regardless of body mass status. Strong associations between perceived weight stigma and weight-related self-stigma have been observed. In a study by Vartanian et al. (75), with 598 participants, pictures of women who were either obese or non-obese were shown to the participants, who assessed them with regards to emotions, attitudes, stereotypes, or desire for social distance. Images of obese individuals inspired more disgust and negative attitudes and stereotypes as well as greater desire for social distance. The researchers concluded that disgust plays an important role in prejudices and discrimination towards obese individuals and that it may partially explain prejudice against overweight people.

We also hypothesised that women affected with psoriasis would differ from the control group in terms of their perceived stigma; however, this hypothesis was not supported by the collected data. Moreover, the severity of the disease, its phase, and the size of affected skin surface also did not impact levels of perceived stigma. This is in line with the research by Rzeszutek et al. (76), which showed that some people affected by psoriasis do not differ in their attitudes from healthy individuals. Moreover, higher satisfaction with their own body and resources allows individuals with psoriasis levels of life satisfaction similar to those of the general population This is also in line with the research by Sakson-Obada and Wycisk (77), who found that accepting one's illness and positive body image and body experiences decreased the negative impact of psoriasis. Thus, positive body image may also facilitate more successful coping with physical symptoms of psoriasis and increase the well-being of patients (78), thereby decreasing perceived stigma.

Interestingly, women who were not overweight and did not suffer from any skin condition, even those with high body fat levels, did not perceive a lack of positive behaviours towards them or lack of compliments. This is in line with previous research (79) that found that women who were not overweight did not associate increased body mass or body fat with lack of friendly behaviours towards them. Contrasting results were observed by Lipowska et al. (33), where lack of perceived friendly behaviours was deemed an important component of stigma and compliments played an important role in building the body esteem of the young female participants, independently of their body mass.

We hypothesised that the attitude towards one's body would be a moderator of the relationship between the objective parameters of the stigmatising illness and perceived stigma. Attitudes towards one's body are developed from the earliest years of life, starting with the stage of getting to know one's own body. After that, these attitudes are shaped and internalised through comparisons with people around us, their opinions, and attitudes towards us. For girls and women, body image comprises a much bigger part of the “self” than is the case for men, and it strongly influences their overall self-esteem (35, 36). From the earliest years of life, women experience stigma and negative judgements associated with increased body mass. One study on a group of children aged 3 to 7 (80) in which participants were asked to describe their preferences for the appearance of playmates as well as to ascribe features attributed to normal and overweight figures revealed that girls are more strict in their judgements of overweight individuals than boys. As per Carof's report (81), despite the fact that European countries vary in their cultures' approaches to overfat and obesity, attitudes towards excess body mass are generally negative and are also often associated with moral judgements of the individual. This is why it is worth emphasising that our results indicate that body mass and its components (fat percentage and visceral fat) play an important role in the relationship with one's own body and perceived stigma. Independently of the objective stigma and body shape (proportions), preoccupation with one's body mass and control over it is a factor that influences one's body image and perceived stigma. Moreover, preoccupation with one's appearance was stronger in the group of obese women than in the remaining groups, and it played an important role in the relationship between objective body dimensions (body fat, visceral fat) and the sense of being stared at because of one's appearance. It can be thus supposed that weight is an important factor in determining to what extent a woman feels attractive, what attitudes she has towards her own body, and whether she perceives weight-related stigma. This is in line with the research of Tovée et al. (82), according to whom body weight explained as much as 53% of the variance in attractiveness among women, while in the case of men it was only 13%. Interestingly, according to the Faries and Bartholomew (83) study, fat percentage seems to be a strong indicator of attractiveness, and the influence of WHR and BMI on attractiveness is partially dependent on it. Despite the fact that multiple studies indicate that women are more preoccupied with their weight than are men (84) and women with higher body mass are more dissatisfied with their appearance (85–87), dissatisfaction with one's appearance and body mass appears to be a universal phenomenon for women (88). Similar results were observed in a study in which all female participants, independently of their body mass and body fat levels, expressed dissatisfaction with their body mass and a desire to reduce it (79). Interestingly, in the study Blodorn et al. (89), women with higher weight, when they were to describe during the study why they would make a good date, and their potential partner would see or hear their recording, felt greater expectations of social rejection when weight was seen (vs. unseen). Experimental studies (90) additionally revealed that showing women who are initially dissatisfied with their bodies images of a very slim “perfect” body significantly increased their levels of dissatisfaction, and led them to judge themselves more harshly. This effect was not observed in women who were initially satisfied with their bodies. Body weight is therefore one of the strongest predictors of satisfaction with one's appearance in women - the lowest level of satisfaction is shown by people with the highest body mass (91).

Moreover, our analyses did not support the existence of a relationship between parameters related to body shape and perceived stigma when the subjective assessment of one's body was tested as a moderator of this relationship. Similar results were observed for a group of Polish and Vietnamese young people (33), for whom objective body measurements did not influence sense of stigma among women. No relationship between anthropometric indices and assessment of one's own body was observed and waist to hip ratio was associated with one's satisfaction with body mass and physical fitness. Moreover, in Polish women, BMI had little influence over assessment of their bodies. This again supports the claim that body mass and its components, and not body shape, influences our attitudes towards our own bodies, and whether we perceive stigma related to our appearance.

A surprising result of the presented study was the positive assessment of one's own health by women affected with psoriasis. This positive assessment seems to lower the levels of perceived stigma, even when body mass or body fat levels are higher. This is in line with the results of a study by Alexandrova-Karamanova (92), who found that young people who assessed their health positively also exhibited more positive feelings and attitudes towards their bodies and appearance. This is even more surprising because psoriasis significantly impacts one's sense of physical attractiveness and acceptance of one's own body (77). A completely different approach towards one's own body and stigma was revealed in the case of obese women. It is likely that women do not treat obesity as an illness per se. Obesity is associated with a number of consequences for one's physical health (93–95); however, these medical conditions are often not directly associated with obesity (in the sense that people not affected by obesity also suffer from these conditions). Thus, it is possible that an individual does not perceive such diseases as associated with obesity, but rather as conditions independent of their appearance, which is why they assess their health differently and pay less attention to the evaluation thereof in the context of their appearance or stigma. Skin conditions require treatment on many levels, such as taking good care of one's skin, alleviating itchiness, regular visits to a specialist, and concealing the affected areas (96, 97). In the case of psoriasis, believing that one has internal control over one's health is associated with the acceptance of the condition, which facilitates adherence to guidelines given by specialists, which, in turn, allows for relatively successful treatment of symptoms (98). Thus, a positive assessment of one's health may allow one to better cope with the physical symptoms of psoriasis and helps reduce stress (which exacerbates the condition) (99).