Variations in the effect of incarceration on community gonorrhoea rates, Guilford County, North Carolina, 2005-2006.

Community incarceration rates have been shown to be associated with rates of HIV and sexually transmitted diseases (STDs). Mechanisms underlying this association include transmission by recently released inmates and community disruption resulting from the absence of incarcerated individuals. We studied the 2006 rates of gonorrhoea at the census tract level in Guilford County, North Carolina (NC) with the previous year's incarceration rates as the exposure of interest. We replicated an analysis conducted in Durham, NC, but unlike in Durham found no meaningful association. When terms were added to the model to allow for a non-linear effect, incarceration levels were associated with rates of gonorrhoea (P < 0.05), indicating the effect of incarceration on gonorrhoea rates differs based on the level of incarceration. Using a spatial model, we found evidence that the association varies across the county. The association between incarceration and gonorrhoea varies by the rate of incarceration and geographically.