DISCUSSION
In the sexual identity group, it was observed that individuals identifying as bisexual or homosexual had a significantly higher prevalence of HBV infection compared to those without any sexual behavior. To account for the potential impact of gender, the data was stratified by gender, revealing that bisexual and homosexual men had a significantly higher prevalence of HBV infection compared to men without any sexual behavior. However, no significant difference was observed among women of all sexual identities. Further analysis was conducted by grouping heterosexual individuals into heterosexual vaginal sex, heterosexual oral sex, heterosexual anal sex, and heterosexual multiple types. The incidence of HBV infection was found to be significantly higher in men with heterosexual anal sex as compared to those without sexual behavior, but no significant difference was observed in three other groups. Bisexual men, homosexual men and men with heterosexual anal sex may be focus populations for the elimination of HBV targets.
It is noteworthy that HBV infection has affected approximately 250 million individuals globally. HBV infection is one of the main causes of liver cirrhosis and liver cancer, increasing the economic burden of the people and the medical burden of the society. Despite the widespread dissemination of HBV medical information and the existence of professional organizations dedicated to the treatment of HBV infection[1], there remains a significant portion of the population who are unaware of their HBV infection status. This lack of awareness poses challenges to follow-up treatment, increases costs, and may even result in secondary transmission[21]. Therefore, it is imperative to expand the dissemination of information regarding HBV screening, transmission routes, vaccination, and the consequences of infection, in order to raise awareness and promote prevention efforts.
Certain studies have suggested that sexual behavior is a significant risk factor for the transmission of HBV[17, 22], and recent data from the United States indicates that approximately one-third of acute HBV infections were associated with sexual behavior during 2013-2018[23]. Despite this, limited research has been conducted on the relationship between sexual type/identity and HBV infection.
Our findings indicate that men with heterosexual anal sex were 4.52 times more likely to contract HBV than men without sexual behavior. However, no significant differences were observed in the risk of contracting HBV through heterosexual vaginal sex, heterosexual oral sex, or heterosexual multiple types of heterosexual sexual behavior. These results suggested that heterosexual anal sex may be a particularly high-risk factor for HBV infection. A literature also reported that heterosexual anal sex contributed to the transmission of HIV[24]. Furthermore, the prevalence of HBV infection was found to be 5.23 times higher in male homosexual sex and 1.69 times higher in bisexual sex compared to men without sexual behavior. Homosexual and bisexual men were identified as being at a greater risk of HCV and HIV infection, which is consistent with the findings of a survey[25]. A research also revealed that the rate of HBV infection in individuals with HIV was 6.5 times higher than in those without HIV[26]. The potential correlation between decreased counts and dysfunction of CD8+ and CD4+ T cells resulting from HIV infection and an increased susceptibility to HBV infection has been suggested as a contributing factor to the higher incidence of HBV co-infection among homosexual and bisexual men[27, 28]. In light of this, preventative measures such as condom use and health screenings for high-risk groups should be prioritized to mitigate transmission.
Nonetheless, the study found no statistically significant disparities among women, regardless of their sexual identity or sexual type. In the study, participants with HBV infection were more likely to be men predominant. The authors, Robin Brown et al., attributed this gender dimorphism to variations in sex hormone levels and immune factors, which may account for the observed differences in HBV infection rates between men and women[29, 30]. Specifically, estrogen and its interaction with estrogen receptors may have a suppressive impact on HBV.
Furthermore, the prevalence of drug use was observed to be higher in the HBV infection group compared to the non-HBV infection group, as reported by Jaimie Z. Shing et al[4]. The study revealed that approximately 20% of adults with a history of drug use were infected with HBV, which was significantly higher than the proportion observed in the general population. Drug use was identified as one of the common modes of HBV transmission[5]. Additionally, previous research has demonstrated that the proportion of smokers is higher in individuals with hepatitis B infection, which aligns with our findings. Furthermore, smoking was correlated with an increased risk of hepatitis B-related liver cancer[31, 32].
To achieve the objective of the World Health Organization to eliminate HBV by 2030, it was imperative to implement measures aimed at reducing the transmission of HBV through sexual behavior pathways[5]. Furthermore, vaccination and regular screening were deemed crucial.
However, our study was subject to certain limitations. The employment of cross-sectional design in NHANES data enabled us to establish a potential association between sexual behavior and HBV infection, but not a causal relationship. Sexual behavior was from questionnaire, maybe some bias existed. Furthermore, the absence of data on protective measures, such as condom use, leading to the absence of this important variable as covariates for the analysis.