Public health nurse density and associated factors across Japan: an ecological study

Ensuring an adequate density of public health nurses (PHNs) is vital for effectively addressing community health needs. This study aimed to (1) map the geographic distribution of PHN density across all 47 prefectures in Japan from 2019 to 2024, (2) investigate regional factors associated with PHN density at the prefectural level, and (3) analyze these associations at different quantile levels of PHN density.

An ecological study was conducted using available public data from 47 prefectures in Japan, focusing on variables related to PHN density such as school density, educational capacity, percentage of graduates selecting PHN careers, percentage of graduates remaining within the prefecture, recruitment rate, and turnover rate. Choropleth maps were created to visually represent geographic distributions. Ordinary least squares (OLS) regression and quantile regression (QR) models were used to analyze the identified regional factors associated with PHN density.

The mean prefectural-level PHN density was 378.0 per million population, with a 3.6-fold difference (range, 172.7-618.4). The results of OLS regression indicated positive associations between PHN density and educational capacity (regression coefficient B = 0.71, standardized regression coefficient β = 0.40, p = 0.016), the percentage of graduates selecting their first career as a PHN (B = 3.29, β = 0.34, p = 0.013), and those selecting their first PHN career within the prefecture (B = 2.15, β = 0.24, p = 0.032). The QR analysis showed that these associations varied across different quantiles. Education capacity was significant in lower (30th percentile) and higher quantiles (90th percentile). The proportion of graduates who started their career as PHNs and those who remained in the prefecture were significant across several quantiles.

Fostering pathways that encourage graduates to pursue public health nursing as their first career choice and remain in their prefectures is essential to enhance prefectural-level PHN density. A balanced approach that addresses both the quantity and quality of PHNs is necessary to advance public health nursing in Japan.