Objective:
To assess the temporal association between melanoma risk and Parkinson disease (PD) diagnosis.
Background:
Individuals with PD are at increased risk of melanoma. The role of dopaminergic drugs remains unclear.
Design/Methods:
Data were obtained from the publicly available Parkinson Progression Marker’s Initiative (PPMI) Online (accessed August 7, 2023). It included 8,417 PD participants, and 20,620 non-PD controls. Data on melanoma was collected retrospectively (at enrollment) and prospectively. Descriptive statistics are reported as median (range) for quantitative, and count (percentage) for categorical variables. Quantitative variables were compared using non-parametric testing (Kruskal-Wallis test). Categorical variables were compared using Fisher’s exact test, or chi square test otherwise.
Results:
Males constituted 59% (n=4951) of the PD and 36% (n=7470) of the non-PD groups. Race was reported as white non-Hispanic by 96% of participants in both groups.
A total of 750 (9%) PD participants reported a history of melanoma, compared to 1034 (5%) in non-PD participants (OR 1.9, 95%CI 1.7-2.0, p<0.001). The risk of developing melanoma was higher prior to being diagnosed with PD (7.1%) compared to after being diagnosed with PD (2.7%) (p<0.001). Participants with a history of melanoma prior to being diagnosed with PD were significantly older at diagnosis (68 years, range 35-91) than those who developed melanoma after being diagnosed with PD (63 years, range 30-80), or without a melanoma history (64 years, range 21-99) (p<0.001).
Conclusions:
PD appears to be associated with an overall increased risk of developing melanoma. The risk seems to be significantly higher prior to being diagnosed with PD compared to after being diagnosed with PD, suggesting no contributing effect of dopaminergic drugs.