Risk factors for hepatitis C infection among Vietnam era veterans versus nonveterans: results from the Chronic Hepatitis Cohort Study (CHeCS).

Research suggests that Vietnam era veterans have a higher prevalence of hepatitis C virus (HCV) than other veterans and nonveterans. However, the reasons for this are unclear, since this research has been conducted among Department of Veterans Affairs (VA) patients and most veterans do not use the VA. The current study compares HCV risk factors between the Vietnam era veterans and nonveterans seen in 4 large non-VA systems to explain this disparity. A total of 4,636 HCV patients completed surveys in 2011-2012. Vietnam era veterans were defined as those who served in the military any time between 1964 and 1975. Bivariate tests followed by logistic regressions, and multivariable modeling were conducted to study risk factors among Vietnam era veterans and nonveterans. Since few veterans were female (~2 %), they were excluded. Among male respondents (N = 2,638), 22.5 % were classified as Vietnam era veterans. Compared to nonveterans, these patients were older (p < 0.001), more educated (p < 0.001), less often foreign born (p = 0.009), more often married (p < 0.001), less often employed, and less likely to have a history of drug abuse treatment (p < 0.001). Comparison of specific risk factor differences for HCV infection by veteran status suggested that while injection drug use approached statistical significance (nonveterans = 46.1 % vs. Vietnam era veterans = 41.4 %, p = 0.06), only reported sex with men was significant (nonveterans = 2.4 % vs. Vietnam era veterans = 0.6 %, p = 0.013). In multivariate logistic regression controlling for age, education, country of birth, marital status and study site, no HCV risk factor was associated with Vietnam era veteran status. However, veterans were more likely to report "other" exposures were the source of infection than nonveterans (p < 0.001). While Vietnam era veterans seen in non-VA facilities do not report a higher prevalence of common HCV risk factors, such as injection drug use, they are more likely to report "other" exposures, typically associated with military service, as the source of HCV infection.