**4. Discussion**

Derived from a large population-based sample, the present study showed that, in line with our hypotheses and previous research [10], individuals with obesity encounter more frequent experiences of workplace bullying than individuals with normal weight. Experiences of workplace bullying were significantly associated with psychological health impairments and emerged as a partial mediator on the associations between higher body weight and elevated burnout symptoms and a lower quality of life, with this effect being particularly evident in women, but not in men. Based on data from real-life employment settings in Germany, the present results extend previous experimental research on sex-specific weight-related discrimination at the workplace, which mainly focused on recruitment and income [7,8,10–13] by experiences of workplace bullying.

In line with our hypotheses and previous research [16–19,39], more experiences of workplace bullying were associated with elevated burnout symptoms and lower quality of life. These associations were substantially stronger than associations between a higher weight status and a greater risk for psychological health impairments. Experiences of workplace bullying partially mediated the association between a higher weight status and elevated burnout symptoms in the total sample, in line with the mediation effect found by Sliter et al. [10] of workplace bullying on the association between weight status and job withdrawal. Further, experiences of workplace bullying partially mediated the association between a higher weight status and a lower quality of life, altogether indicating that a higher weight status alone is linked to psychological health impairments, while additionally experiencing workplace bullying is associated with a further increased health risk. However, because the associations between weight status and psychological health impairments were only reduced to a small extent (Δβ's ranging from 0.02 to 0.03) after including experiences of workplace bullying, the mediation effects may not be necessarily clinically relevant. Importantly, owing to design, the present results depict cross-sectional associations, leaving unclear the causal mechanisms between weight status, experiences of workplace bullying, burnout symptoms, and quality of life. Thus, all mediation effects must be interpreted considering this important limitation.

Differences in experiences of workplace bullying between women and men across the weight range were shown within sex-specific subsamples in the path analyses, in which a higher weight status was significantly associated with more frequent experiences of workplace bullying in women (Model 3), but not in men (Model 4), replicating findings by Sliter et al. [10] within a larger and representative sample from the general population. However, we found no weight status-by-sex interaction effect on the level of experiences of workplace bullying in the univariate statistics, as previously revealed by Sliter et al. [9]. In the present study, only descriptively, experiences of workplace bullying tended to be increased in women with obesity compared with men with obesity (*p* = 0.28, *d* = 0.24). In contrast to Sliter et al. [10], who showed that men with underweight were more likely to experience workplace bullying than women with underweight, in the present study, we excluded participants with underweight owing to the small sample size (*n* = 25, 1.9%), which may explain the lack of the interaction effect in the present study.

In the present study, derived from both the path analyses and the SPSS PROCESS macro [37], partial mediation effects found in the total sample were evident for women, but not for men, indicating sex-specific differences regarding the adverse psychological health correlates of workplace bullying. In women, but not in men, a higher weight status had direct and indirect effects on elevated burnout symptoms and a lower quality of life, with these associations being partially mediated by experiences of workplace bullying. Thus, while women with obesity were at risk for elevated burnout symptoms and a lower quality of life, those who additionally experienced workplace bullying showed an even increased health risk. Considering the deleterious impact of burnout symptoms on a range of adverse medical conditions (e.g., type 2 diabetes and coronary heart disease), mental health (e.g., insomnia and depressive symptoms), and occupational outcomes (e.g., low job satisfaction and absenteeism) [40], and given that future longitudinal studies could replicate the present findings, employers and policy makers might further address workplace bullying, potentially preventing medical and psychological health impairments for workers and associated productivity losses for organizations [20,41].

Strengths of the present study comprise the use of established measures to depict work-related psychological health impairments within a large sample from the general population, which was representative for the German population both in terms of sex ratio and SES [42,43], and included participants from real-life employment settings, as previously recommended [7]. However, the sample was not generally representative for the prevalence of obesity, as obesity was underrepresented in the present sample (6.4%) as compared with the German general population (23.6% [44]), which might be explained by participants' impression management, specifically by an underreporting of body weight, which was previously found in individuals with BMI ≥ 20 kg/m2, and an overreporting in those with BMI < 20 kg/m2 [45]. As this bias in self-reported BMI is of high concern for large epidemiological studies within obesity-related research, studies investigating novel methods of large-scale measurement of weight and height are urgently needed (e.g., corrective equations or BMI self-selection [46,47]). A major limitation of the present study is that all analyses used cross-sectional data, leaving unclear the causal mechanisms between body weight, experiences of workplace bullying, and work-related psychological health impairments. Ideally, studies from non-Western countries might replicate our procedures to allow generalization of the results. Finally, as no specific information on participants' occupation was provided, it was not possible to systematically examine the effects considering other possibly relevant work-related variables, such as the number of colleagues or type of work sector.

Most importantly, future research should explore the prospective associations between body weight, experiences of workplace bullying, and psychological health impairments to elucidate their causal relationships. The present result that individuals with obesity, compared with those with normal weight, encounter more frequent experiences of workplace bullying, with the latter being more strongly linked to work-related psychological health impairments than the weight status, suggests continued efforts by researchers and employers to address and eventually reduce experiences of workplace bullying (e.g., by incorporating information on bullying into existing education platforms within the workplace [48,49]). As our study did not focus on discrimination owing to ethnicity or race, future studies should take discriminated features other than weight and sex (e.g., low SES and mental disorders [50,51]) into account when exploring the adverse effects of stigmatization. Our results suggest that, especially in women with obesity, who are at particular risk of experiencing weight-related discrimination in various life domains [52], different discriminated features (i.e., weight status and sex) may add up to multiple layers of stigmatization. Thus, especially in women with obesity, reducing experiences of workplace bullying will likely yield a decreased psychological burden of employees, and might strengthen their health status and lower their odds of adverse occupational outcomes (e.g., job withdrawal or absenteeism).

**Supplementary Materials:** The following are available online at https://www.mdpi.com/article/ 10.3390/nu13113867/s1, Supplementary Table S1: Sex-specific experiences of workplace bullying and psychological health impairments across the weight status: Mean values and standard deviations.

**Author Contributions:** E.B., A.H., J.K. and M.Z. designed and organized the initial survey and participated in selection of measures. H.-C.P., R.S. and A.H. designed the study, H.-C.P. wrote the manuscript. R.S., A.H., M.Z., J.K. and H.K. revised the manuscript. All authors have read and agreed to the published version of the manuscript.

**Funding:** A.H. and R.S. were supported by the German Federal Ministry of Education and Research (grant 01EO1501).

**Institutional Review Board Statement:** The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Ethics Committee of the University of Leipzig (Approval No. 072-11-07032011), and followed the ethical guidelines of the International Code of Marketing and Social Research Practice by the International Chamber of Commerce and the European Society for Opinion and Marketing Research.

**Informed Consent Statement:** Oral informed assent and consent was obtained from the participants ≥18 years and, for participants <18 years, informed consent was obtained from the parents, which is common in survey research in Germany.

**Data Availability Statement:** Research data are not shared.

**Conflicts of Interest:** The authors declare no conflict of interest.
