# Risk factors for Q fever incidence in Korea: a comparative analysis using frequentist and Bayesian methods

## TL;DR

This study identifies slaughterhouse density as a key risk factor for Q fever in Korean cities and livestock density in provinces, highlighting the need for region-specific prevention strategies.

## Contribution

The study compares frequentist and Bayesian methods to identify Q fever risk factors and reveals regional differences in Korea.

## Key findings

- Slaughterhouse count was positively linked to Q fever in cities using Bayesian models.
- Livestock population was a significant risk factor in provinces.
- Bayesian methods provided more stable inference with limited data and probabilistic uncertainty estimates.

## Abstract

This study investigated the principal determinants of human Q fever incidence and explored regional variation between metropolitan cities and provinces in Korea.

Panel data on human Q fever incidence, livestock populations, and facility metrics were collected across 17 metropolitan cities and provinces from 2017 to 2024. Analytical approaches included frequentist models (ordinary least squares [OLS], random effects [RE], fixed effects [FE]) and Bayesian models.

Frequentist panel analysis indicated that slaughterhouse count was positively associated with Q fever incidence in both pooled OLS (β=1.20, p<0.001) and RE models (β=1.03, p<0.001), but not in the FE model (β=0.14, p=0.65). After correcting for serial correlation using Driscoll-Kraay standard errors, livestock population (β=0.55, p<0.01), livestock market count (β=-2.01, p<0.05), and livestock Q fever cases (β=-0.11, p<0.01) were significantly associated with human incidence. A Bayesian FE model confirmed a significant relationship between slaughterhouses and human Q fever incidence (posterior mean: 0.87; 95% credible interval [CrI], 0.21 to 1.42), providing more stable inference with limited samples and allowing probabilistic uncertainty estimation. A Bayesian hierarchical model revealed a stronger association in metropolitan cities (posterior mean, 1.46; 95% CrI, 0.34 to 2.57) than in provinces (1.22), while livestock population remained significant in provinces (0.94; 95% CrI, 0.15 to 1.74).

In Korea, slaughterhouse density was the main determinant of Q fever in metropolitan cities and livestock density was the primary risk factor in provinces. These findings underscore the need for region-specific preventive strategies and reinforce the value of a One Health approach.