Geographic Variation of HIV Infection with Different Risk Factors in Taiwan

Background: The three main high-risk groups for HIV infection in Taiwan are men who have sex with men (MSM), heroin injection drug users (IDU), and persons who have unprotected heterosexual sex. Formulating the appropriate control strategy for HIV epidemics among these high-risk groups requires the knowledge whether the transmission networks and locations overlap or not in the first place. To maximize the effectiveness, HIV preventive programs need to be delivered according to the locations of specific populations. Genotyping analysis and qualitative researches suggested that different high-risk groups have distinct social transmission networks and social contexts generally. However, the extent of overlapping has not been known. Moreover, there is no study which explores and analyses the spatial distribution of HIV infection. If high-risk groups have different geographic distributions, we must allocate resources according to the locations of target groups and establish appropriate policy. bjectives: The main purpose of this research is to examine whether HIV-infected groups with different risk factors could be distinguished as different HIV epidemics from the aspects of geo-spatial as well as socioeconomic factors.ethods: We examine the geo-spatial distributions of different HIV-infected group by constructing two scales of data to analysis: explore the spatial distributions of sexually transmitted HIV-infected group and IDU-related HIV-infected group in Taiwan by township level, and the spatial relationship within the MSM group, IDU group and heterosexuality group (HIV-infected patients of National Taiwan university Hospital) in Northern Taiwan by point data. We would like to inspect whether there was spatial association or dependency between different HIV-infected groups and compare their geographic distribution by spatial pattern analysis and spatial cluster detection method. econd, we would like to perform a population-based study to examine the relationship between distribution of HIV infection and socioeconomic factors (degree of urbanization, sexually active population, level of economy and education at township level and see if HIV-infected groups with different risk factors have the different socioeconomic determinants. Moreover, we try to explore the spatial relationship between HIV-infected patients’ residential locations and gay places where MSM easily take high-risk sexual behavior. Through this relationship we could investigate whether there are different HIV-infected groups from the spatial aspect by comparing the average distances to gay places. esults: (1) Spatial distributions of HIV-infected groups with different risk factors were not identical and the sexually transmitted HIV epidemic (MSM and Heterosexuality) was more clustered than IDU-related HIV epidemic. The former was more likely to reside in urban places, but the latter was more concentrated in the suburban area. Although the spatial distributions were not the same, there were locations where clusters overlapped. (2) HIV epidemics with different risk factors had different socioeconomic determinants. Sexually transmitted HIV cases were more likely to occur in townships with high average household income, high level of education, and high degree of urbanization; while IDU-related cases were more likely to occur in townships with lower income, middle-level of education and middle degree of urbanization. (3) There was significant shorter distance to gay places for MSM cases in comparison with IDU or heterosexual cases. However, spatial dependency was not found between MSM and gay places, which may be explained by the observation that MSM resided in residential district but gay places were located in business district generally. onclusions: HIV epidemics among groups with different risk factors were not similar in geo-spatial distribution and socioeconomic determinants. We identified the locations of clusters for HIV-infected groups and the possible place where high-risk groups would concentrate. It is necessary to develop suitable program and strategies for specific high-risk groups at the appropriate locations.ey words: HIV infection, spatial analysis