Impact of new migrant populations on the spatial distribution of tuberculosis in Beijing

The tuberculosis (TB) case notification rate in Beijing has been increasing since 2000. Migration was speculated to play an important role in promoting the growth of the epidemic. The identification of spatial clusters of TB can be a key indicator for targeting limited public health resources.

Spatial modelling was applied to the 220 towns of Beijing and summarised for the 18 districts, which were combined into four functional areas in 2005 and 2006. Population density was combined with the numbers of TB cases, and TB incidence data was used to identify high rate clusters. A negative binomial regression model was used to confirm the association between TB and migration status in Beijing.

There were 4584 TB cases among permanent residents and 2838 among migrants. TB cases and population were most densely grouped in four central districts. High-rate TB clusters in both permanent residents and migrants were detected in the 'New Districts for Urban Development' and Chaoyang District in 2005 and 2006. Migration and the population growth rate of new migrants are contributing to the TB increase in Beijing.

The increasing migrant population has had a drastic influence on the spatial distribution of TB in Beijing. Spatial analysis could provide additional information in addition to common incidence plots.