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

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. 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. 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). 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.