Spatial heterogeneity and drivers of pulmonary tuberculosis in Guangzhou: a street-level analysis of residents and migrant subgroups from 2015 to 2023
摘要
Rapid urbanisation and internal migration may reshape fine-scale tuberculosis (TB) risk within cities, yet street-level evidence by migrant subgroup remains limited. We quantified the street-level spatial heterogeneity of pulmonary TB in Guangzhou, China, and assessed individual- and area-level drivers to inform risk-stratified active case finding and targeted prevention strategies.
MethodsWe analysed 74,449 pulmonary TB cases from Guangzhou's TB surveillance system (2015–2023). Cases were categorised according to household registration as registered residents, intra-provincial migrants (within Guangdong), or inter-provincial migrants (outside Guangdong). We calculated street-level incidence and mapped spatial patterns. Hotspots were identified using the local Getis-Ord Gi* statistic. Subgroup risk patterns were compared using adaptive-kernel log-relative risk surfaces. A multilevel Bayesian logistic regression model was used to identify individual-level factors associated with hotspot residence, accounting for street-level clustering. Alternative random-effects structures, including spatial specifications, were compared during model selection. Street-level environmental determinants were assessed using hierarchical Bayesian negative binomial models fitted with INLA and multi-source indicators.
ResultsTB incidence showed substantial street-level spatial heterogeneity, with hotspots concentrated in the central urban core. Age-standardised incidence was highest among inter-provincial migrants (47.24 per 100,000), followed by residents (42.69 per 100,000) and intra-provincial migrants (28.86 per 100,000). However, inter‑provincial migrants were less likely to reside in hotspots compared with residents (aOR = 0.850, 95% CrI: 0.740, 0.987). Cases detected via active screening were also less likely to live in hotspots relative to those identified through symptom‑based consultation (aOR = 0.396, 95% CrI: 0.168, 0.931). In the Bayesian model, a higher street-level per capita GDP was associated with an increased TB risk (relative risk [RR] per one standard deviation [SD] increase = 1.184, approximately equivalent to a 1,000 Chinese yuan increase), while a higher proportion of intra-provincial migrants was associated with a decreased risk (RR per one SD increase = 0.895, approximately equivalent to a 10 percentage-point increase). Incidence among inter-provincial migrants correlated with the TB burden in provinces of origin (ρ = 0.56).
ConclusionPulmonary TB in Guangzhou exhibits pronounced street-level spatial heterogeneity. This study found that active screening was associated with a lower likelihood of residing in a TB hotspot after accounting for street-level clustering, suggesting that estimates may be biased if this geographic context is ignored. Two priority profiles emerged from the analysis: older adults living in central hotspot communities, and inter-provincial migrants who had the highest overall incidence and a clear ecological linkage to origin-province burden. We therefore recommend risk-stratified, spatially targeted interventions, including intensified active screening for the elderly in hotspot streets, and enhanced cross-provincial coordination for TB control among inter-provincial migrants.