Exploring tuberculosis by types of housing development.

Tuberculosis (TB) is known as a disease of poverty. It has also been related to poor living environment. This study examines the relationship between TB outcome and housing characteristics which is reflective of the socio-economic standing. We sought to investigate the association from two novel angles: (1) TB outcome against floor level of residence, and (2) TB outcome against types of housing development. A total of 1787 culture-positive TB cases were collected by the Centralized Mycobacterium Laboratory from 2007 to 2009. Most of the cases fell in the catchment area of the Kowloon West Cluster, a densely populated urban area in Hong Kong. The distribution of culture-positive TB cases by floor levels of residence and types of housing was examined by descriptive and non-parametric statistical analyses. The effects of vertical distance of residence from the street level on TB outcome by different types of housing development were further explored by regression methods. Our study confirmed more TB cases among tenants on the lower floors and observed a decreasing trend towards higher floors. It also revealed that significantly more TB cases were residing in public as opposed to private or other types of housing (Chi-square = 151.14, p < 0.0001). Regression analysis by different housing types showed significantly different rates of change between floor number and TB cases (p < 0.0001). Our findings offer evidence on the inverse associations between floor levels of residence and TB occurrences and showed that the patterns were dependent on housing types. We demonstrated how housing characteristics could be useful input in an ecological study of the TB disease. These results have significant design and health implications for Asian cities that are getting denser and growing taller.