In this blog, I will discuss a recent systematic review and meta-analysis on eating disorders (EDs) among international immigrants by Siddiqi et al. (2024).
The “healthy immigrant effect”, a phenomenon in immigration research for the last few decades, suggests that immigrants have better overall health compared to the relative domestic population (Elshahat et al., 2022). This might seem a bit backwards, considering the many challenges immigrants can face (i.e., discrimination, employment difficulties, trauma, etc.), but experts state that this could be a result of immigration policies, in which healthier and more educated individuals are more likely to choose or be allowed to migrate (Brabete, 2017).
There is a gap in understanding EDs among the migrant population, and whether this is another condition that could be associated with the healthy immigrant effect. EDs affect nearly 9 million people globally (Eating Disorder Statistics, 2022), and are one of the most misunderstood mental health conditions (Marzola et al., 2022). Siddiqi et al. (2024) have published the first systematic review to address the prevalence of EDs in international immigrants compared to local populations.
The “healthy immigrant effect” refers to a phenomenon in immigration research where immigrants are found to have better overall health in comparison to local populations. But is this the case for eating disorders?
Methods
The authors searched four major databases to identify studies of:
- Population: First-generation immigrants of all ages, genders, etc.
- Exposure: “International migration”, as defined by the Office of the High Commissioner for Human Rights
- Comparator: Local populations
- Outcome: Any ED (e.g., anorexia nervosa [AN], bulimia nervosa [BN], binge eating disorder [BED], etc.)
- Study design: All observational study types.
Manual searching of reference lists was also undertaken to ensure that all relevant studies were captured. Non-English studies were included, but there was no mention of unpublished studies or grey literature.
The meta-analysis was conducted using a random effects model to pool the prevalence odds ratios (ORs) across included studies. A narrative synthesis was used for any studies that did not provide enough data to calculate ORs. Risk of bias was assessed using the NIH Quality Assessment Tool for Observational Cohort and Cross-sectional Studies.
Results
Ten studies were included in the review, six of which were eligible for the meta-analysis. All included studies were based in high-income countries, with most using a cross-sectional design (n = 7). Studies included data from 64,000+ participants, most of which investigated any ED (n = 6), although two studies focused on BED, one study on BN and BED, and one study on AN. Quality assessment of the six studies included in the meta-analysis showed that the majority had a good rating (n = 4), with the rest being fair (n = 1) or poor (n = 1).
Meta-analysis
The results of the meta-analysis found that, compared with domestic populations, immigrants had an OR of 0.45 (95% CI [0.35 to 0.59]), indicating 55% reduced odds of an immigrant experiencing an ED.
However, when investigating heterogeneity, the reviewers explored the effect of different diagnostic instruments for EDs. Studies that used the Eating Disorder Examination (EDE) reported 31% reduced odds among immigrants, whereas those using the SCOFF instrument (Sick, Control, One, Fat, Food) reported 84% increased odds among immigrants.
Narrative synthesis
Interestingly, the four studies included in the narrative synthesis found different results, where there was either no effect of migration of ED prevalence (n = 3), or there was a higher prevalence of EDs in immigrant populations (n = 1).
In Siddiqi et al.’s (2024) meta-analysis of six studies, immigrants had 55% reduced odds of experiencing an eating disorder in comparison to the local population.
Conclusions
The findings from this meta-analysis suggest that immigrants may have a reduced likelihood of experiencing an ED in comparison to local populations. However, due to the small size of the meta-analysis, combined with potential confounders like age and type of diagnostic tool used, it is not possible to confirm whether this finding is reliable.
It is important to note that this systematic review focused exclusively on prevalence rates derived from official diagnoses. The authors highlighted a significant limitation in this approach: many immigrants are less likely to seek out healthcare services due to various barriers, such as lack of access, cultural differences, and stigma. As a result, the data presented may not be comprehensive and could fail to accurately reflect the overall health status of the entire immigrant population, particularly those who might be experiencing EDs but have not received a formal diagnosis.
While this meta-analysis indicates that the prevalence rates of eating disorders among immigrants may be lower than local populations, the lack of studies, potential confounders, and focus on formal diagnoses means the findings should be interpreted with caution.
Strengths and limitations
This systematic review had a well-established search strategy, including major databases as well as hand-searching reference lists. Study inclusion and data extraction was also undertaken by two independent reviewers. This increases our confidence that all relevant studies were captured.
Although the inclusion of non-English language studies was a great help in broadening the scope of evidence, the use of Google Translate in data screening is not a reliable tool for translation. Parallel and back translation would be preferred methods, and should be considered in future studies.
Additionally, there was a high degree of heterogeneity across the studies included in the meta-analysis, and therefore the overall result (lower prevalence of EDs) could be explained by confounders.
Finally, there was no inclusion of unpublished research or grey literature. Considering the studies included in this review had differing results based on a number of different factors, it would be beneficial in limiting publication bias to include any unpublished work that may be of relevance.
A strength of Siddiqi et al.’s (2024) meta-analysis was the inclusion of non-English language studies. However, their use of Google Translate to do this is not ideal, when parallel and back translation are preferred methods.
Implications for practice
The main finding from this meta-analysis is that the prevalence of EDs may be lower in immigrants than domestic populations, providing support for the healthy immigrant effect.
However, we cannot be certain of the reliability of these findings. More high-quality cross-sectional and longitudinal research is needed in this area to allow for higher power analyses in different subgroups.
Future research should also aim to provide more specific results based on migration-specific factors that may influence certain groups differently, and a better understanding of the influence of diagnostic tools.
However, as the authors mentioned, the outcomes of this meta-analysis are not necessarily generalisable to the wider population, particularly as immigrants are less likely to access healthcare. This means that there is a much larger piece of work needed to increase the accessibility of mental healthcare for immigrants, which can be done by identifying and tackling experienced barriers and enhancing facilitators (see Anamarija’s Mental Elf blog to read more about barriers and facilitators for mental health support in Europe-based female migrants).
It is also important to consider that the presentation of EDs in immigrants may differ from domestic populations (Mellor et al., 2013; Pike & Dunne, 2015), which clinicians need to be aware of in practice. Cultural and contextual factors may also further complicate diagnosis, particularly in low- and middle-income countries (LMICs) and among underrepresented groups, leading to potential misinterpretation and minimisation.
In practice, it is important for clinicians to be aware that how eating disorders present in immigrants may differ from presentations in local populations.
Statement of interests
None.
Links
Primary paper
Siddiqi, S., Akther, A., Blair, D.-L., Eccles, H., Frangione, B., Keeshan, A., Nagi, S., & Colman, I. (2024). Eating disorders among international migrants: a systematic review and meta-analysis. Social Psychiatry and Psychiatric Epidemiology, 59(9), 1483-1495.
Other references
Brabete, A. C. (2017). Chapter 8 – Examining Migrants’ Health From a Gender Perspective. In M. P. Sánchez-López & R. M. Limiñana-Gras (Eds.), The Psychology of Gender and Health (pp. 231-250). Academic Press.
Eating Disorder Statistics. (2022). National Association of Anorexia Nervosa and Associated Disorders. Retrieved December 13 from https://anad.org/eating-disorders-statistics/
Elshahat, S., Moffat, T., & Newbold, K. B. (2022). Understanding the healthy immigrant effect in the context of mental health challenges: A systematic critical review. Journal of Immigrant and Minority Health, 24(6), 1564-1579.
Marzola, E., Panero, M., Longo, P., Martini, M., Fernàndez-Aranda, F., Kaye, W. H., & Abbate-Daga, G. (2022). Research in eating disorders: the misunderstanding of supposing serious mental illnesses as a niche specialty. Eating and Weight Disorders-Studies on Anorexia, Bulimia and Obesity, 27(8), 3005-3016.
Mellor, D., Waterhouse, M., bt Mamat, N. H., Xu, X., Cochrane, J., McCabe, M., & Ricciardelli, L. (2013). Which body features are associated with female adolescents’ body dissatisfaction? A cross-cultural study in Australia, China and Malaysia. Body Image, 10(1), 54-61.
Pike, K. M., & Dunne, P. E. (2015). The rise of eating disorders in Asia: a review. Journal of Eating Disorders, 3, 1-14.
Veic, A. (2024). Navigating mental health support for female migrants in Europe: insights from a systematic feminist review. The Mental Elf.
