Moreover, other risk factors have been linked to homeless veterans, some including, poverty, social isolations, mental health disorder, associations between PTSD and combat experience, and behavioral health disorders, particularly, substance abuse disorders. To emphasize, two studies were done to examine homelessness among the OEF and OIF veteran cohort, Blackstock et al., finding that 17% veterans of 445,319 records from the US Department of Veterans Affairs have been homeless and that their homelessness is associated with socioeconomic and demographic factors (unmarried, black race, lower educational attainment, urban location, and Hispanic ethnicity). The second study, Edens et al., assessed homelessness, based on VA records, for 1.1 million veterans from all eras who received mental health services in 2009. The overall study group, 10% were identified as having experienced homelessness, whereas only 4% of the OEF-OIF veterans in this group were so identified. In the methodology, data for the study came from an LC database and administrative records for 310,685 veterans who separated from active military duty from July 1, 2005, to September 30, 2006: aged 17 to 64 years of their separation from military service, which they had no indication of a homeless episode in the DoD and VA records before their separation from the military and who used VA or DoD services after