Prevalence of Parkinson's disease in a town of the central highlands of Peru: A population‐based study 

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This study provides a community-based estimate of Parkinson’s disease prevalence in Jauja, a town in the central Andes of Peru, using a two-phase, door-to-door methodology. PD is the second most common neurodegenerative disorder globally, yet epidemiological data from Latin America, particularly in Andean regions, remain limited. This study addresses that gap by focusing on an underserved population with distinct environmental and sociocultural characteristics. 

We screened 1,960 individuals using a two-phase approach: phase 1 consisted of door-to-door screening with an adapted 9-item questionnaire for parkinsonism, and phase 2 involved neurological confirmation of suspected cases by movement disorders specialists. A total of 21 PD cases were identified, 16 through the screening strategy, yielding a crude prevalence of 816 per 100,000 inhabitants and an age-standardized prevalence of 566 per 100,000. These estimates are consistent with global reports but exceed those previously reported for Andean Latin America. Prevalence increased markedly with age, particularly among individuals over 80 years, reinforcing ageing as the strongest risk factor. 

A key finding was that 10 of 21 PD cases were newly diagnosed, highlighting substantial underdiagnosis in the region. Limited access to specialized neurological care, low disease awareness, and sociocultural interpretations of motor symptoms as part of normal ageing likely contribute to delayed diagnosis. The absence of neurologists and reliance on primary care may further contribute to this diagnostic gap. 

Clinically, most patients presented with typical PD features, with tremor as the most common initial symptom. Cognitive screening revealed low MoCA scores, suggesting a high burden of impairment; however, this finding should be interpreted cautiously given potential educational and cultural influences. A marked male predominance in PD prevalence was observed; potential explanations include differences in occupational exposures and access to healthcare, although these were not formally evaluated. 

Environmental exposures were assessed among PD cases: most lived in close proximity to agricultural activity and some reported pesticide use; however, these findings remain exploratory due to the study design and lack of a control group. Genetic screening did not identify pathogenic variants in known PD-related genes, supporting the multifactorial nature of the disease. 

The study also highlights the logistical and cultural challenges of conducting epidemiological research in Andean communities, including mistrust toward research activities and barriers to participation. Importantly, the response rate for neurological confirmation was 60%, and non-response may have led to an underestimation of the true prevalence. 

In conclusion, PD prevalence in this Andean population appears comparable to global estimates but is likely under-recognized due to healthcare disparities. Improving access to neurological care, increasing awareness, and implementing culturally adapted research strategies should be prioritized in underserved regions. 

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