We identified the variation of prevalence and factors of self-reported screening and vaccination behaviors among three Asian American ethnic groups. Previous studies have not compared ethnic-specific differences in barriers for HBV screening behaviors based on various cultural and immigration background. Asian Americans and immigrants are disproportionally affected by chronic HBV and liver cancer. A large proportion of people infected with HBV were unaware of their disease status and even if diagnosed, many of them were not receiving treatment [28
]. An important step for better management of severe liver diseases caused by HBV is to encourage high-risk populations to get screening and vaccination. Our findings also confirm that physician recommendations and being a newer immigrant are important factors for HBV prevention behaviors. Our research also suggested that there are substantial differences for self-reported infection rates and factors associated with screening and vaccination behaviors among Chinese, Korean, and Vietnamese Americans.
From the participants' self-reported data, the Chinese American sample in the Baltimore- Washington Metropolitan Area has the highest screening rate among the three ethnicities, yet they have the lowest self-reported infection rate. The self-reported rate may be an underestimated number compared to actual screening results, partially because some people may not comprehend a screening result without clear explanation from their physicians, did not follow up, or forget their status. Studies that tested serum HBsAg among Asian American immigrants show that HBV infection rates could range widely depending on the study populations and locations, such as 4.3% in a Rocky Mountain area and 14.8% in a New York City sample [5
]. The self-reported infection rate in our Chinese sample (5%) is much lower than the Chinese sample gathered in New York City (21.4%) or the Korean sample and Vietnamese sample in our study (18 and 15%, respectively) [5
One possible explanation for this result is that the infection status may be underreported because of the stigma against chronic HBV among Chinese Americans and our data was collected by self-report. China has a long history of stigma against people infected with HBV, mainly due to the loss of employment opportunity and education admission policies against chronic HBV patients. For example, since the 1980s children infected with chronic HBV virus were not allowed to go to ordinary kindergartens in Guangzhou, China [29
]. Only recently, there were clear governmental regulations against HBV discrimination. In 2007 there were regulations prohibiting employers from rejecting job applications by people with chronic HBV [30
]. In 2009 the Ministry of Health proposed regulations assuring children who are HBV positive to enter kindergarten and allowing people with chronic HBV to work in the food industry [30
]. To protect people's right to work regardless of their HBV status, in February 2011, the Ministry of Health prohibited hospitals from carrying out HBV tests for companies as part of pre-employment physical examinations [31
]. These changes of regulations within the past 5 years might not have changed persistent misunderstandings and discrimination among Asian Americans and immigrants. Hence, underreporting may be one explanation for the lower infected rate among Chinese Americans in our study. We need serological HBV testing to confirm this hypothesis and better survey methods to deal with potential underreporting of HBV status.
In our study sample, the Vietnamese group had the lowest self-reported screening and vaccination prevalence compared to Chinese and Korean populations. Since HBV vaccines were introduced and covered nationwide in immigrants' home countries in different years, more research is needed to target specific ethnic groups for screening and vaccination. In China, HBV vaccination was first introduced in 1985; in 2002 it was extended to all newborns at no cost. By 2005, infant coverage was 72% [32
]. For South Korea, national coverage started in 1992; by 2005 infant coverage reached 92% [32
]. HBV vaccination was first introduced in Vietnam in 1997 and covered nationally in 2003; by 2005, infant coverage reached 94% [32
]. The later introduction and prevalence of HBV vaccines could be the reason why immigrants from some Asian countries have lower coverage, which should be addressed by raising awareness among physicians, other health care providers, and among immigrants themselves.
We found that being a newer immigrant was associated with more frequent HBV screenings compared to those who had lived in the United States for more than a quarter of their lifetime. This may also be contributed by the variation of when HBV vaccinations were introduced in each country. In our study, the average age of arriving in the United States was about 30 years and more than 50% of the total sample was above 40 years of age. These immigrants did not benefit from the child HBV vaccination policies since the policies were introduced in the 1990s. There may be a certain age cohort who immigrated in a time period that made them more vulnerable for missing HBV preventive services in both their home country and the US. Identifying the age and time of arriving in the US for immigrants could help to effectively target populations at high risk.
Several factors significantly associated with immigrants' screening and vaccination behaviors were consistent with the literature, such as knowledge of HBV, physician recommendations and family or friends' recommendations [7
]. Conversely, after adjusting for sociodemographics and patient and provider-related barriers in the full sample or ethnic-specific analysis, we did not find that having health insurance was significantly associated with most screening and vaccination behaviors [8
]. A few reasons may explain this discrepancy compared to the literature. It could be that those who did obtain screening and vaccinations had these preventive behaviors back in Asia, so whether they currently had health insurance in the US was not associated with their preventive behaviors. In our multivariate model, other important factors such as knowledge of HBV and physician recommendations, may have stronger effects than the health insurance issue. In addition, to be protected for life, HBV screening needs to be conducted only once in a lifetime and vaccinations obtained once. This is quite different from other cancer screenings. The cost of liver cancer prevention behaviors through HBV screening is rather cheaper than other cancer prevention behaviors. If they are knowledgeable about HBV, immigrants without health insurance may be more likely to choose liver cancer prevention than other cancer prevention behaviors due to the lower cost. Future studies should test whether the cost of each preventive behavior is part of the decision-making process for immigrants.
Our findings suggest that having a regular physician and physician recommendations are significantly associated with vaccination behaviors among Korean Americans; health insurance did not show association with either screening or vaccination behaviors. The Korean sample in our study had the lowest health insurance coverage among the three ethnic groups (52 vs. 78% for Chinese, 69% for Vietnamese). The lower health insurance coverage among Korean Americans is an alarming issue concerning health outcomes in the long term [33
]. This may explain why physician recommendations are more important than having insurance for Korean immigrants to receive vaccinations. More research effort is needed to examine how health insurance coverage affects health care utilization among Asian immigrants.
An important limitation of our study is that the prevalence of chronic HBV infection was self-reported, without the confirmation of serological testing. This may underestimate the infection rate due to the history of stigma against HBV in some cultures. Also, we do not have data on when and for what purpose participants obtained HBV screening tests. Factors associated with screening may be very different from the general population for those who obtained screening due to having jobs involved with blood-borne pathogens in the medical field, or screening during pregnancy for women. Our study results are not generalizable to other Asian populations in the US. Our recruitment is based on a convenience sampling method, recruiting through community-based organizations, faith-based organizations, and others and differed by each ethnicity group. It is possible that people were more interested in or knowledgeable about HBV, then self-selected to our study. Therefore, it is possible that our findings may not accurately report the prevalence of HBV screening and immunization practice of general Asian American populations in the region. We tried to diversify the sample by recruiting in markets and restaurants to recruit immigrants with lower socioeconomic backgrounds, but still our study results should not be generalized to other Asian immigrant samples collected by different methods and in other locations. The extent of generalizability of our study findings can be assessed when the United States 2010 Census data become publicly available.
In summary, our study used a sample of adult Chinese, Korean and Vietnamese Americans recruited in Maryland and found that education, knowledge of HBV, and physician recommendations are consistently associated with screening and vaccination behaviors. We also found that prevalence and factors for HBV preventive behaviors differ among each ethnic group. We should continue the effort to improve HBV knowledge among immigrants and encourage physician practices to recommend screening for high-risk groups. Only less than one-third of primary care physicians were found to routinely assess risk factors against HBV and vaccinate patients with risk factors in a national survey conducted in year 2006 [34
]. Immigrants with lower education and lower HBV knowledge are particularly vulnerable and in need of physicians' reminders. More research is needed to examine how culture and immigration backgrounds of each Asian ethnic group may affect preventive health behaviors. Based on the differences of patient-, resource-, and physician-related barriers associated with HBV preventive behaviors among each ethnic group, we should design comprehensive interventions, but with focus on certain factors for each Asian ethnic group.