Association of the Naples prognostic score with Parkinson disease risk: a prospective cohort study

Background The Naples prognostic score (NPS), derived from routine inflammatory and nutritional biomarkers, reflects systemic immune–metabolic status. Its prospective association with Parkinson disease (PD) risk has not been well established. Methods We analyzed 317,035 UK Biobank participants recruited in 2006–2010 who were free of PD and malignancy at baseline and had complete NPS component data. NPS was derived from serum albumin, total cholesterol, neutrophil-to-lymphocyte ratio, and lymphocyte-to-monocyte ratio. Incident PD through 31 December 2022 was identified using a validated algorithm. Associations were examined using Cox proportional hazards models with multivariable adjustment. Results Over a median follow-up of 13.94 years, 2,298 participants (0.72%) developed PD. Higher NPS was significantly associated with increased PD risk. After multivariable adjustment, each 1-point increase in NPS corresponded to a 13% higher risk (Model 2 adjusted HR = 1.13, 95% CI: 1.07–1.19, p < 0.001). Compared with participants with NPS = 0, those with moderate to high NPS scores (2–4 points) had progressively elevated risks (NPS = 2: HR = 1.16, 95% CI: 1.03–1.31; NPS = 3: HR = 1.53, 95% CI: 1.29–1.82; NPS = 4: HR = 2.08, 95% CI: 1.21–3.58; all p < 0.05), showing a clear dose–response relationship ( p for trend < 0.001). Conclusion In this large prospective cohort, higher NPS was independently associated with increased PD risk. These findings support the potential role of integrated inflammatory–nutritional status in PD development and suggest that NPS may serve as a readily available marker for risk stratification.