Association between the prevalence of neurological diseases and the density of board-certified neurologists: ecological cross-sectional analysis

BACKGROUND: Neurological diseases are often difficult to diagnose, and their prevalence is increasing with population aging. In Japan, the role of board-certified neurologists in facilitating the identification and registration of neurological diseases remain unclear. This study aimed to investigate the association between the regional distribution of board-certified neurologists and the prevalence of neurological diseases. METHODS: We conducted ecological cross-sectional analysis using prefecture-level data from the Japan Intractable Disease Information Center for fiscal year 2022, including 11 designated neurological intractable diseases. Disease prevalence, neurologist density, and the proportion of older adults (≥ 65 years) were obtained from national databases. Linear regression was used to adjust disease prevalence for aging effects, and Spearman rank correlation coefficients were calculated between adjusted prevalence and neurologist density. RESULTS: Significant positive correlations were observed between adjusted prevalence and board-certified neurologist density for multiple system atrophy (MSA, rho = 0.464), Parkinson’s disease (PD, rho = 0.445), and progressive supranuclear palsy (PSP, rho = 0.303; all p < 0.05). CONCLUSIONS: Regions with higher densities of board-certified neurologists had higher observed prevalence of MSA, PD, and PSP after adjusting for aging, suggesting that regional differences in access to neurological care (as proxied by board-certified neurologist density) may contribute to differences in case detection and registration. These findings highlight the importance of optimizing neurologist distribution to enhance access to equitable care.