Study Investigates Ties Between Vitiligo and Parkinson’s Disease

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Researchers behind a recent population-based study aimed to clarify the association between vitiligo and Parkinson’s disease (PD), noting that knowledge on the subject is sparse. Through their investigation of the bidirectional epidemiological association, researchers concluded that vitiligo is associated with a lower risk of developing PD. They also found the presence of comorbid PD predisposes patients with vitiligo to elevated mortality and cardiometabolic outcomes.¹

Data Collection

The study utilized Clalit Health Services database records spanning from2002 to 2019to collect data using both a cohort study and a case-control study design. First, a retrospective cohort study design was used to follow patients with vitiligo and estimate the incidence of new-onset PD. Second, a case-control study design was used to estimate the prevalence of preceding PD in patients with subsequent vitiligo. The researchers behind the study noted that, considering the rare disease assumption, the latter design is likely to delineate the odds of vitiligo after PD.

To be eligible for the study, patients had to have: (1) a documented diagnosis of vitiligo as registered by a board-certified dermatologist, or (2) a diagnosis of vitiligo in discharge letters from dermatological wards. The diagnosis of PD was based on documentation from a certified neurologist.Adjusted hazard ratio (HR) and odds ratio (OR) were calculated by multivariate Cox and logistic regressions, respectively.

Results

A total of 123,326 participants were included in the study. Researchers identified 20,851 of the participants as patients with vitiligo, and 102,475 as age-, sex and ethnicity-matched controls. They noted the mean (SD) age at vitiligo diagnosis was 34.7 (22.4 years).

Researchers estimated the incidence rate of PD at 2.9 (95% CI, 2.1–4.1) and 4.3 (95% CI, 3.8–4.9) cases per 10,000 person-years among patients with vitiligo and controls, respectively. Relative to the control group, they noted patients with vitiligo had a significantly decreased risk of PD (HR, 0.68; 95% CI, 0.48–0.98; p = 0.037). In sex- and age-stratified analyses, researchers found the reduced risk of PD was only significant among males (HR, 0.61; 95% CI, 0.38–0.98; p = 0.041) and older individuals (age ≥ 32.4; HR, 0.68; 95% CI, 0.47–0.97; p = 0.034). In a multivariate analysis adjusting for demographics and comorbidities, the study discovered vitiligo was associated with a significantly reduced risk of PD (fully-adjusted HR, 0.62; 95% CI, 0.43–0.89; p = 0.009; Table 2).

Preexisting PD was observed in 59 (0.3%) patients with vitiligo included in the study and 31 (0.4%) controls. Researchers noted the development of subsequent vitiligo was not significantly associated with a history of PD (OR, 0.80; 95% CI, 0.61–1.06; p = 0.116). In an age- and sex-stratified analysis, the study saw no significant association between a history of PD and subsequent vitiligo except for the female sex group, where an inverse association was found (OR, 0.67; 95% CI, 0.45–0.99; p = 0.043). In a multivariate logistic regression analysis controlling for demographic variables and comorbidities, researchers found the odds of vitiligo were statistically comparable after PD (fully-adjusted OR, 0.80; 95% CI, 0.61–1.06; p = 0.117).

Finally, the researchers aimed to characterize vitiligo patients with comorbid PD as compared to the remaining patients with vitiligo. They found the presence of PD in patients with vitiligo was “significantly” associated with older age, Jewish ethnicity, obesity, smoking, ischemic heart disease, hyperlipidemia, hypertension, and diabetes mellitus.

Discussion

Through this study, researchers found vitiligo confers a protective role against the development of PD, as patients with vitiligo are less susceptible to experiencing subsequent PD. They observed that relative to other patients with vitiligo, those with vitiligo and comorbid PD were at a 2.5-fold elevated risk of all-cause mortality and had a greater burden of cardiometabolic comorbidities.

The researchers noted several other studies have examined evidence suggesting that PD might be associated with an autoimmune theme,^2,3 including a recent meta-analysis that found a positive association between PD and comorbid autoimmune disease.⁴ They found little information or research on the association between PD and vitiligo prior to this study, and suggested that further research is necessary to establish or refute it.

References

1. Kridin K, Ofir L, Weinstein O, et al. Clarifying the association between Parkinson's disease and vitiligo: a population-based large-scale study. Front Neurol. 2024;15:1387404. Published 2024 May 21. doi:10.3389/fneur.2024.1387404
2. Tansey MG, Wallings RL, Houser MC, et al. Inflammation and immune dysfunction in Parkinson disease. Nat Rev Immunol. 2022;22(11):657-673. doi:10.1038/s41577-022-00684-6
3. Tan, EK., Chao, YX., West, A. et al. Parkinson disease and the immune system — associations, mechanisms and therapeutics. Nat Rev Neurol 16, 303–318 (2020). https://doi.org/10.1038/s41582-020-0344-4
4. Li M, Wan J, Xu Z, et al. The association between Parkinson's disease and autoimmune diseases: A systematic review and meta-analysis. Front Immunol. 2023;14:1103053. Published 2023 Jan 25. doi:10.3389/fimmu.2023.1103053