Effects of red meat and processed meat intake on prodromal Parkinson's disease in Chinese adults aged 55 and above: A prospective cohort study

[Background] Gastrointestinal microbiota plays an important role in the development of Parkinson's disease（PD）, and dietary factors have a great impact on intestinal micro ecology. At present, few studies focus on red meat and PD, especially prodromal PD（pPD）.[Objective] To understand the relationships of the intake of red meat and processed meat products with pPD and the number of risk/prodromal markers, and to explore the association of dietary factors with pPD.[Methods] Based on the data of Community-based Cohort Study on Nervous System Disease in2018 and 2020, adults aged 55 years and older with complete demographic information, dietary survey information, and information on risk factors related to PD were selected from four provinces of China. After excluding those reporting abnormal total energy intake or those reporting alcohol drinking or abused drugs for a long period of time, and confirmed mental diseases with prescribed drugs, a total of 10 003 subjects were included. Food frequency questionnaire was used to calculate the intake of red meat and processed meat products. The pPD-related risk/prodromal markers were selected following the International Parkinson and Movement Disorder Society criteria for pPD, and the risk level and the number of markers of pPD were then calculated. The relationship between the intake of red meat and processed meat and the risk level of pPD was analyzed by multiple linear regression. The relationship between the intake of red meat and processed meat and the pPD marker number groups was analyzed by multinomial logit regression model.[Results] In 2018, the intake of red meat and processed meat was 28.57 g·d-1 in the target population. In 2020, the median of the number of risk/prodromal markers was 3, and the median M(P25, P75) of the posterior probability of pPD was 0.74%（0.42%, 1.49%）. The multiple linear regression analysis showed that the higher the intake of red meat and processed meat, the higher the risk level of pPD in follow-up（b=0.021, P < 0.05）. The multiple logit regression model showed that compared with the lowest quartile（Q1）, the highest quartile（Q4）group of red meat and processed meat intake were more likely reporting 3-5 risk/prodromal markers than ≤ 2 risk/prodromal markers（OR=1.185, 95%CI: 1.015-1.382）.[Conclusion] The intake level of red meat and processed meat is related to the risk level of pPD, and a higher intake of red meat and processed meat may be a potential risk factor of pPD.