Mediterranean diet is associated with a lower probability of prodromal Parkinson's disease and risk for Parkinson's disease/dementia with Lewy bodies: A longitudinal study

Abstract Background and purpose Lifestyle factors have been implicated in the long‐lasting neurodegenerative process in prodromal Parkinson's disease (pPD). The aim was to investigate the associations between adherence to a Mediterranean diet (MeDi) and longitudinal changes of pPD probability and the development of Parkinson's disease (PD) or pPD in a Mediterranean older population. Methods Data from the Hellenic Longitudinal Investigation of Aging and Diet cohort (community‐dwelling individuals, aged ≥ 65 years) were used. A detailed food frequency questionnaire was used to evaluate dietary intake and calculate MeDi adherence score, ranging from 0 to 55, with higher scores indicating higher adherence. The probability of pPD was calculated according to the updated Movement Disorder Society research criteria. Results In all, 1047 non‐PD/dementia with Lewy bodies (DLB) participants were followed for 3 ± 1 years. MeDi adherence was associated with lower increase in pPD probability over time ( b = −0.003, 95% confidence interval −0.006 to −0.001, p = 0.010). Forty‐nine participants had incident possible/probable pPD (i.e., pPD probability ≥ 30%). Compared to the participants in the lowest quartile of MeDi adherence, those in the higher quartiles had an approximately 60%–70% lower risk for possible/probable pPD ( p for trend 0.003). MeDi–pPD associations were driven by both motor and non‐motor pPD markers and not from risk markers. Also, 21 participants were diagnosed with PD/DLB at follow‐up. For each unit increase in the MeDi score, there was a 9%–10% lower risk for PD/DLB (hazard ratio 0.906 [95% confidence interval 0.823–0.997], p = 0.044). Conclusions Mediterranean diet adherence is associated with lower increase in pPD probability over time and lower possible/probable pPD and PD/DLB incidence in older Mediterranean people. More studies are needed to confirm our results in other populations.