Studies have shown that people with serious mental illnesses engage with behaviors that predispose them to sexually transmitted and blood-borne infections, including HIV, hepatitis B and C, and syphilis (
9,
10). Although there are many studies in different countries on this issue and the importance of paying attention to this group regarding blood-borne infections, the prevalence of HBV and HCV in this group has not been studied in Iran. Our results showed that the prevalence of HCV in people with serious mental illnesses was significantly higher than the prevalence reported in the general population of Iran.
In the serological examination, the prevalence of HCV-Ab, HBsAg, HBsAb, and HBcAb was 3.1%, 0.3%, 18.7%, and 7.3%, respectively. In a similar study in Sweden, the prevalence of HBV in people with serious mental illnesses was 0.53%, compared to 0.22% in the general population, and the prevalence of HCV was 4.58%, in comparison with 0.61% in the general population (
14). The results of the current study showed that the prevalence of HBsAg in people with serious mental illnesses (0.3%) was lower than in the general population (1.09%) (
4). The reason for the low percentage of hepatitis B in this group can be vaccination. This study also showed that the prevalence of hepatitis B in this group was much lower than the prevalence of hepatitis B in people with serious mental illnesses in Asia (9.7%) (
7). In a study, Kramvis et al. examined the serological prevalence of hepatitis B and C in people with serious mental illnesses in Nigeria and reported that the frequencies of hepatitis B and C in people with serious mental illnesses were 10.0% and 12.6%, respectively, in comparison with 10.9% and 1.1% in blood donors, respectively. Thus, there was a significant difference in the prevalence of HCV in the studied population compared to blood donors (
15). Furthermore, this study showed that the prevalence of HCV-Ab was higher in people with serious mental illnesses than in the general population of Iran (
16). Accordingly, it should be noted that people with serious mental illnesses are among the groups with a high prevalence of hepatitis C in Iran. Due to the increasing trend of mental disorders in Iran, special attention should be paid to the screening of this group for HCV infection. Moreover, the results of the present study, compared to the findings of other studies conducted in other countries in this particular group, showed that HCV was less prevalent in Iran than in Asia (4.4%) (
17).
The simultaneous detection of HBsAb and HBcAb is indicative of hepatitis B exposure, while the detection of HBsAb alone is indicative of vaccination. According to the findings of this study, 11.4% of the participants were only positive for HBsAb, meaning that they were already vaccinated and immune against HBV. However, there is a possibility for the clearance of vaccine-induced antibodies in long-term after receiving the vaccine, but vaccinated people who have even cleared the antibodies are immune against HBV transmission. In a similar study, Mohamadnezhad et al. investigated hepatitis B markers in thalassemia and dialysis patients and showed that among 94 samples, 12.8% were HBsAg positive, 57.4% were HBsAb positive, and 13.8% were HBcAb positive, while 42.6% of the study population were not immune against HBV (
18).
Similar epidemiological studies on high-risk behaviors in this population reported risk factors such as injecting drugs and unprotected sexual behaviors (
7). In a study by Bauer-Staeb et al., age (OR: 1.003) and the history of using drugs (OR: 4.11) were significantly associated with hepatitis B and C infections (
14). In the current study, in addition to determining the prevalence of viral hepatitis in this group, we also examined their related risk factors, identifying that age (OR: 1.06) and tattooing (OR: 4.94) were significantly associated with hepatitis B infection (HbcAb), as revealed in a multiple regression model. Our results showed that the percentage of exposure increased with age, which could be related to vaccination in people under 30 years of age.
Besides, in the multiple regression model, hepatitis C had a significant relationship only with the history of having tattoos (OR: 6.33). Although the chance of exposure to HCV was 3.7 times higher in married people than in single people and 4.22 times more in people living independently than in people living with the family, these differences did not reach a statistically significant level. However, more multi-centric studies are needed, including other provinces and larger sample sizes, to better understand high-risk behaviors and estimate the prevalence of HBV and HCV infections in this population.
One of the limitations of this study was the lack of cooperation of a number of medical centers in conducting this research, which of course, the coronavirus disease 2019 pandemic played a key role in this regard. The response of study participants to questionnaires was also subjected to their mental and physical conditions, and it seems that these patients are more inclined to conceal their behaviors, making it difficult to analyze their high-risk behaviors. Finally, the results of this study were obtained from two hospitals in Tehran and cannot be extrapolated to the general population of individuals with mental illnesses in Iran because the sample population from these hospitals located in Tehran showed a higher level of urbanization than in other provinces of Iran. This is important as the prevalence of mental disorders varies between rural and urban communities.