Fig. 2

Modified Gelberg-Andersen Behavioral Model for Vulnerable Populations, as applied to MSM and their utilization of sexual health services. Each box represents one of the categories impacting health service utilization and health: outcomes (green), predisposing (purple), enabling (yellow), need (red), and health behavior (blue). Each box includes bolded headings showing factors which fall under each category, and bulleted examples falling under each heading. Traditional factors affecting the whole population’s service utilization are above the dashed line, while factors relevant to vulnerable populations are below the dashed line. Specific examples of these domains reflected in the results from our data have been added to the model in italics. The arrows linking the boxes represent the cyclical nature of the model, with predisposing and enabling factors, need, and health behaviors both impacting and being impacted by health outcomes. Our data showed a bidirectional relationship between health behaviors and need, represented by the arrow from the health behavior (blue) to the need (red) box