A longitudinal study of anti-SARS-CoV-2 antibody seroprevalence in a random sample of the general population in Hiroshima in 2020.

BACKGROUND: This longitudinal study aimed to determine chronological changes in the seroprevalence of prior SARS-CoV-2 infection, including asymptomatic infections in Hiroshima Prefecture, Japan. METHODS: A stratified random sample of 7,500 residents from five cities of Hiroshima Prefecture was selected to participate in a three-round survey from late 2020 to early 2021, before the introduction of the COVID-19 vaccine. The seroprevalence of anti-SARS-CoV-2 antibodies was calculated if at least two of four commercially available immunoassays were positive. Then, the ratio between seroprevalence and the prevalence of confirmed COVID-19 cases in Hiroshima was calculated and compared to the results from other prefectures where the Ministry of Health, Labour and Welfare conducted a survey by using the same reagents at almost the same period. RESULTS: The numbers of participants in the first, second, and third rounds of the survey were 3025, 2396, and 2351, respectively and their anti-SARS-CoV-2 antibodies seroprevalences were 0.03% (95% confidence interval: 0.00-0.10%), 0.08% (0.00-0.20%), and 0.30% (0.08-0.52%), respectively. The ratio between the seroprevalence and the prevalence of confirmed COVID-19 cases in Hiroshima was 1.2, which was smaller than that in similar studies in other prefectures. CONCLUSIONS: The seroprevalence of anti-SARS-CoV-2 antibodies in Hiroshima increased tenfold in a half year. The difference between seroprevalence and the prevalence of confirmed COVID-19 cases in Hiroshima was smaller than that in other prefectures, suggesting that asymptomatic patients were more actively detected in Hiroshima.

Comparison of liver disease state progression in patients with eradication of versus persistent infection with hepatitis C virus: Markov chain analysis.

To investigate the long-term prognosis of liver disease in patients with hepatitis C virus (HCV) eradication after antiviral therapy versus those with persistent HCV infection. Four hundred and eighty patients (5259 person-years [PYs]) who received interferon-based therapy and achieved sustained virologic response and 848 patients (3853 PYs) with persistent HCV infection were included. In the analysis of 1-year liver disease state transition probability matrices using Markov chain models, progression to cirrhosis from the chronic hepatitis state was observed (0.00%-0.63%) in patients with HCV eradication. Among patients with chronic hepatitis or cirrhosis and HCV eradication, hepatocellular carcinoma (HCC) development was observed in males aged ≥ 50 years (0.97%-1.96%) and females aged ≥ 60 years (0.26%-5.00%). Additionally, in patients with cirrhosis and HCV eradication, improvement to chronic hepatitis was also observed (4.94%-10.64%). Conversely, in patients with chronic hepatitis and persistent HCV infection, progression to cirrhosis was observed in males aged ≥ 30 years and female aged ≥ 40 years (0.44%-1.99%). In males aged ≥ 40 years and female aged ≥ 50 years with cirrhosis, the transition probability for HCC was relatively high (4.17%-14.02%). Under the assumption of either chronic hepatitis or cirrhosis at age 40 or 60 years as the starting condition for simulation over the next 30 or 40 years, respectively, the probability of HCC was higher in patients with persistent HCV infection than those with HCV eradication. In conclusion, HCV eradication can reduce the risk of developing cirrhosis or HCC in patients with chronic HCV infection.

Eighteen-year follow-up cohort study on hepatitis B and C virus infections related long-term prognosis among hemodialysis patients in Hiroshima.

This study aimed to investigate the prevalence trend of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections and their genotype distribution among hemodialysis patients, determining their long-term prognosis and the risk factors to the mortality. This cohort study used both the medical data and the blood samples of hemodialysis patients at nine dialysis centers in Hiroshima from 1999 to 2017. Hepatitis B surface antigen (HBsAg) and anti-HCV were screened and then amplification was done to positive sera by polymerase chain reaction for genotyping. Data were employed for multiple regressions to determine the associated risk factors. A total of 3968 patients were subdivided into three groups: who started hemodialysis before 1990, during 1991 to 2001, and after 2002. The periodic prevalence of HBsAg decreased from 2.8% to 1.3% and that of anti-HCV from 33.3% to 9.5% in the three groups. By multiple regressions, the adjusted hazard ratio of diabetes mellitus (DM) ranges from 1.59 to 2.12 and that of HCV RNA positivity ranges from 1.18 to 1.48 (P < .05). Heart failure is the primary cause of death in all groups. Genotype C2 is predominant for HBV and genotype 1b is predominant for HCV. The decreasing trend of both HBV and HCV was found in the cohort. DM and HCV RNA were the significant risk factors leading to poor prognosis among hemodialysis patients. The similar genotype distribution of both HBV and HCV was found as general population. This alarmed to provide early diagnosis, prompt, and adequate treatment to HCV infection among hemodialysis patients.

Existence of hepatitis B virus surface protein mutations and other variants: demand for hepatitis B infection control in Cambodia.

BACKGROUND: This study aimed to detect Hepatitis B virus (HBV) genome sequences and their variants as of nationwide scale using dried blood spot (DBS) samples and to provide up-to-date reference data for infection control and surveillance in Cambodia. METHOD: Among 2518 children age 5-7 years and their 2023 mothers participated in 2017 Cambodia nationwide sero-survey on hepatitis B surface antigen (HBsAg) prevalence using multistage random sampling strategy, 95 mothers and 13 children positive to HBsAg were included in this study. HBV DNA was extracted from DBS, then performed polymerase chain reaction. HBV genotypes and potential variants were examined by partial and full length genomic analysis. RESULTS: HBsAg positive rate was 4.7% (95/2023) in mothers and 0.52% (13/2518) in their children. Genotype C (80.49%) was abundantly found throughout the whole Cambodia whilst genotype B (19.51%) was exclusively found in regions bordering Vietnam. S gene mutants of HBV were found in 24.29% of mothers and 16.67% of children with HBV DNA positive sera. Full-length genome analysis revealed the homology of 99.62-100% in each mother-child pair. Genotype B was clarified to recombinant genotype B4/C2 and B2/C2. Double (48.39%) and combination mutation (32.26%) were observed in core promoter region of HBV C1 strains. CONCLUSIONS: This study showed the capable of DBS for large-scale molecular epidemiological study of HBV in resource limited countries. Full-genome sequences yield the better understanding of sub-genotypes, their variants and the degree of homology between strains isolated from mother-child pairs calls for effective strategies on prevention, control and surveillance of mother-to-child HBV transmission in Cambodia.

Long-term prognosis of liver disease in patients with eradicated chronic hepatitis C virus: An analysis using a Markov chain model.

AIM: The long-term prognosis of patients with chronic hepatitis C virus (HCV) infection who have received antiviral therapy and who demonstrate HCV eradication remains incompletely characterized. In this study, we investigated the long-term prognosis of liver disease in patients with eradication of HCV. METHODS: A total of 552 patients with chronic HCV infection (6815 person-years) who were treated with interferon-based therapy and who achieved sustained virologic response were included. Yearly transition probabilities for each liver state (chronic hepatitis, cirrhosis, and hepatocellular carcinoma [HCC]) were calculated using a Markov chain model. RESULTS: In the analysis of 1-year liver disease state transition probabilities, progression to cirrhosis occurred in 0.5-2.1% of male patients with chronic hepatitis across all age groups. In male patients with cirrhosis, HCC developed in 0.6-1.9% of patients over the age of 50 years. In female patients with chronic hepatitis, progression to cirrhosis occurred in 0.4-2.1% of patients across all age groups. In addition, in female patients with cirrhosis, HCC developed in those aged 60-69 (0.4%) and 70-79 (0.4%) years. Under the assumption of either a chronic hepatitis or cirrhosis state at age 40 or 60 years as the starting condition for simulation over the next 40 or 20 years, respectively, the probability of HCC gradually increased with age and was higher in male patients. CONCLUSIONS: The development or progression of cirrhosis and the development of HCC are risks in HCV patients despite HCV eradication, not only in those with cirrhosis but also in those with chronic hepatitis.

Natural history of liver-related disease in patients with chronic hepatitis C virus infection: An analysis using a Markov chain model.

BACKGROUND: Long-term prognosis of patients with chronic hepatitis C infection (HCV) remains incompletely characterized. We investigated the long-term prognosis of liver disease in patients with chronic HCV infection who have not received antiviral therapy. METHODS: A total of 2304 patients with chronic HCV who were not received interferon-based therapy were included. RESULTS: In the assessment of 1-year disease state of liver transition probabilities, progression to chronic hepatitis occurred in 12% to 14% of patients across all age groups in male asymptomatic carriers. In male patients with chronic hepatitis, progression to cirrhosis was observed mostly in the 60 to 69 (7.6%) and ≥70 age groups (9.6%). In addition, in male patients with cirrhosis, HCC development occurred in approximately 5% of patients over the age of 40. In female asymptomatic carriers, progression to chronic hepatitis was observed in 6% to 14% of patients across all age groups. In female patients with chronic hepatitis, progression to cirrhosis was observed mostly in the 60 to 69 (8.7%) and ≥70 (7.4%) age groups. In addition, in female patients with cirrhosis, HCC development occurred in 0.9% to 3.3% of patients over the age of 50. Under assumptions of either chronic hepatitis or asymptomatic carrier state at age 40 as the starting condition for simulation over the following 40 years, the probability of HCC gradually increased with age and was higher in male patients. CONCLUSIONS: There is a risk of cirrhosis or HCC development in HCV patients with not only chronic hepatitis but the asymptomatic carrier state as well.

Natural course of persistent hepatitis B virus infection in hepatitis B e antigen-positive and hepatitis B e antigen-negative cohorts in Japan based on the Markov model.

This population-based study examined the natural course of hepatitis B e antigen (HBeAg)-positive or HBeAg-negative persistent hepatitis B virus (HBV) infection, adjusted by age and liver disease states using a Markov model. Using 12 417 person-years data (n = 862), annual transition probabilities were estimated, and age-adjusted cumulative incidence and natural history of persistent HBV infection were simulated in both sexes of groups 1 (HBeAg-negative status with HBV DNA level <4.0 log IU/mL at entry) and 2 (persistent HBeAg-positive status throughout the study). In group 1, 15.26% of 30-years old men with chronic hepatitis (CH) were expected to remain in the same state at age 65 years, 28.32% subsided into an hepatitis B surface antigen (HBsAg)-negative state, and 13.20% developed hepatocellular carcinoma (HCC). The expectations for 40-years old men in group 1 were 21.43%, 19.86%, and 15.04%, respectively. The expectations for 30 years women in group 1 were 30.57%, 21.15%, and 4.08%, respectively. These results suggest that HBeAg positivity caused a higher risk of HCC onset in persistent HBV infection after adjustments for age, sex, and liver disease state. HCC was likely to develop, but unlikely to subside into HBsAg clearance, remaining in a CH state with aging, regardless of HBeAg state. Furthermore, both HCC development and HBsAg clearance occurred more frequently in men than in women, irrespective of HBeAg status.

Cost-effectiveness analyses of anti-hepatitis C virus treatments using quality of life scoring among patients with chronic liver disease in Hiroshima prefecture, Japan.

AIM: We estimated the cost-effectiveness of direct-acting antiviral treatment (DAA) compared to triple therapy (simeprevir, pegylated interferon-α [Peg-IFN], and ribavirin [RBV]) (scenario 1), Peg-IFN + RBV (scenario 2), and non-antiviral therapy (scenario 3). METHODS: Cost-effectiveness was evaluated as incremental cost-effectiveness ratios (ICERs) using direct costs and indirect costs, which included loss of wages during the patient's lifetime due to early death caused by viral hepatitis infection. Quality of life (QOL) scores were determined by EQ-5D-3L questionnaire survey on 200 HCV patients in Hiroshima. RESULTS: The QOL scores for chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma were estimated as 0.871, 0.774, and 0.780, respectively. The follow-up period that the ICER of scenario 1 becomes shortest (cost <¥6 million) was 25 years after treatment in men and women who started treatment at the age of 20-60. In contrast, those of scenarios 2 and 3 was 10 years after treatment in patients who started treatment at age <80 years. Based on the sensitivity analysis in scenario 1, the most significant factor affecting the value of ICER is the QOL score after sustained virologic response (SVR), followed by the SVR rate of DAA or follow-up period. CONCLUSIONS: Direct-acting antiviral treatment was estimated to be cost-effective from 10 to 25 years after treatment, depending on the SVR rate of the drugs and the age of onset of treatment. In order to increase the cost-effectiveness of DAA treatment, measures or effort to improve the QOL score of patients after SVR are necessary.

Pilot study for hepatitis virus screening among employees as an effective approach to encourage employees who screened positive to receive medical care in Japan.

AIM: Countermeasures against hepatitis B and C virus (HBV, HCV) infection at work sites in Japan have not yet been implemented. This study aimed to determine the status of viral hepatitis infection among employees in Japan. METHODS: We undertook a workplace-based cross-sectional study from 2011 to 2016 in Hiroshima, Japan. Hepatitis B virus and HCV markers were identified during a routine checkup of employees in 15 enterprises. The screening results were sent to employees directly and not to employers. A thorough examination of the participants who screened positive was encouraged by forwarding to them a referral letter by our research group to specialized medical institutions. RESULTS: Of the 3015 employees, 2420 (80.3%) underwent hepatitis virus screening. Of these, 13.8% had been screened for hepatitis virus before this survey. The prevalence of hepatitis B surface antigen was 0.95% (n = 23; 95% confidence interval, 0.6-1.3%). The prevalence of hepatitis B core antibody was as high as 31.5% at age 60-69 years, and 41.5% at age 70 years and over. The HCV carrier rate was 0.45% (n = 11; 0.2-0.7%) and 54.5% of them had genotype 2. Thirty-four carriers were detected, and 44.1% of them were detected for the first time; 53.3% of the newly detected carriers visited medical institutions with the referral, and underwent a periodic follow-up or treatment. CONCLUSION: Promoting hepatitis virus screening for employees may help detect carriers who are unaware of their infection and require treatment. Submitting the results to employees with a referral letter to medical institutions at the time of positive diagnosis may be effective.

A seroepidemiological survey of the effect of hepatitis B vaccine and hepatitis B and C virus infections among elementary school students in Siem Reap province, Cambodia.

AIM: This study aimed to survey the prevalence and incidence of hepatitis B (HBV) and hepatitis C virus (HCV) infection among elementary school students in Siem Reap province, Cambodia and to evaluate the effects of a national infant HBV vaccination program introduced in 2001. METHODS: Students in 3rd grade during the 2011, 2012, and 2013 academic years were enrolled in this study; at the time of the second examination, in the 2014-2015 academic year, the students were in 5th or 6th grade. The incidence and prevalence rates of HBV and HCV infection were estimated and full HBV sequences were analyzed. RESULTS: Among 248 students (107 male and 141 female) born between 1999 and 2005, five students were HBV surface antigen (HBs-Ag) positive (2.02%), and all of them were infected with genotype C. Among them, subgenotype C1 was found in four students and, unexpectedly, complete genetic sequence identity of subgenotype C1 was found in two students from different families. The anti-HBV core (HBc) and anti-HBs prevalence rates were 10.89% and 16.13%, respectively. Twenty-five students were positive for anti-HBs and negative for both HBsAg and anti-HBc (10.08%; estimated serological vaccination rate); this rate increased significantly with the birth year (P = 0.0229). Prevalence of anti-HCV was 2.82%, and HCV RNA was not detected. The estimated incidence of HBV and HCV infection were both 0/1000 person-years (PY) (95% confidence interval, 0-20.61/1000 PY and 0-14.50/1000 PY, respectively). CONCLUSION: Hepatitis B virus full-genome sequencing and serological analysis revealed the possibility of horizontal transmission of HBV among Cambodian schoolchildren. However, the anti-HBc positivity rate decreased along with increasing age and estimated serological vaccination rates.

Incidence and risk factors of colorectal cancer based on 56 324 health checkups: A 7-year retrospective cohort study.

BACKGROUND AND AIM: Although mortality rates of colorectal cancer (CRC) have been increasing in Japan, its screening rates remain stagnant at 19.2% among Japanese population aged > 40 years in 2014. To evaluate the importance of CRC screening by fecal occult blood test (FOBT), this study estimated the incidence of FOBT-positivity and CRC by sex-age stratification and clarified the risk factors for CRC. METHODS: Between 2007 and 2014, 56 324 residents (21 517 men and 34 807 women) were enrolled in this study. The sex-age-stratified incidence rates of FOBT-positivity and CRC were estimated by records from health checkups and colonoscopy. Regarding CRC incidence rate in particular, positive predictive value was adopted to adjust bias of FOBT-positivity that did not undergo colonoscopy by person-year method. To investigate the risks of CRC onset, a nested case-control study with 1:10 person-matching on sex and age was performed. RESULTS: Incidence rates of FOBT-positivity and CRC are 4183/100 000 person-year (100 Kpy) and 141.3/100 Kpy, respectively. In both cases, men has higher incidence rate than women (1.3 times for FOBT; 4977 vs 3718/100 Kpy and 2.3 times for CRC; 217.0 vs 96.4/100 Kpy). CONCLUSIONS: The records from health checkups were useful to estimate incidence rates of CRC with this procedure. The age-stratified incidence rate indicated the importance of CRC screening by FOBT, especially for men and those aged > 50 years. Additionally, it is strongly recommended to do further investigation if positive for initial FOBT screening especially for those who are > 70 years.

High prevalence of hepatitis B infections in Burkina Faso (1996-2017): a systematic review with meta-analysis of epidemiological studies.

BACKGROUND: Hepatitis B virus (HBV) infection was long considered an important public health concern in Burkina Faso and still represents a major cause of liver cancer and cirrhosis in the active population. To counter the problem, a national strategic plan was developed and adopted in July 2017 to coordinate viral hepatitis elimination's efforts. However evidence to support its implementation remains scanty and scattered. The main purpose of this study was to summarize available information from per-reviewed articles published over the last two decades to accurately estimate the prevalence of HBV infection in Burkina Faso. METHODS: We conducted a systematic search with meta-analysis of scientific articles using Science-Direct, Web-of-Science, PubMed/Medline, and Google Scholar. We systematically assessed all relevant publications that measured the prevalence of hepatitis B surface antigen and which were published between 1996 and 2017. We estimated the national HBV prevalence and its 95% confident interval. We subsequently adjusted the meta-analysis to possible sources of heterogeneity. RESULTS: We retrieved and analyzed a total of 22 full text papers including 99,672 participants. The overall prevalence was 11.21%. The prevalence after adjustment were 9.41%, 11.11%, 11.73% and 12.61% in the general population, pregnant women, blood donors and HIV-positive persons respectively. The prevalence was higher before implementation of HBV universal vaccination and decreased from 12.80% between 1996 and 2001 to 11.11% between 2012 and 2017. The prevalence was also higher in rural area 17.35% than urban area 11.11%. The western regions were more affected with 12.69% than the central regions 10.57%. The prevalence was 14.66% in the boucle of Mouhoun region and 14.59 in the center-west region. Aggregate data were not available for the other regions. CONCLUSIONS: HBV has clearly an important burden in Burkina Faso as described by its high prevalence and this problem significantly challenges the national health care system. There is an urgent need for effective public health interventions to eliminate the problem. However, higher quality data are needed to produce reliable epidemiological estimates that will guide control efforts towards the achievement of the national strategic plan's goals.

Reduced prevalence of hepatitis B surface antigen positivity among pregnant women born after the national implementation of immunoprophylaxis for babies born to hepatitis B virus-carrier mothers in Japan.

AIM: We aimed to estimate hepatitis B surface antigen (HBsAg) positivity among birth year-stratified pregnant women in Hiroshima, Japan, and compare prevalence rates between women born before and after implementation of a national immunoprophylactic vaccination program for babies born to hepatitis B virus (HBV) carrier mothers in Japan. METHODS: Pregnant women who gave birth at all delivery hospitals/clinics in Hiroshima prefecture between 1 April 2010 and 31 March 2011 were eligible. Lists collected from each institution included survey items such as age (pregnant woman's birth year) and HBsAg and hepatitis C virus (HCV) antibody (anti-HCV) test results, which were posted anonymously and non-consolidated from medical records. We calculated the HBsAg and anti-HCV prevalence in our cohort according to the mothers' birth year. RESULTS: In 41 of 58 hospitals/clinics, 15 233 and 15 035 pregnant women underwent HBsAg and anti-HCV testing, corresponding to 59.6% and 58.9% of 25 546 births in the 2010 fiscal year, respectively. The overall HBsAg positive rate was 0.51% (95% confidence interval [CI], 0.40-0.63%), and an extremely low prevalence (0.10%; 95% CI, 0.00-0.25%) was observed among pregnant women born after 1986. However, the prevalence in this study was slightly higher than the nationwide value (0.31%) and the Chugoku region-specific value (0.46%) among first-time blood donors at Japanese Red Cross blood centers between 2001 and 2006. No significant difference in anti-HCV positivity was observed. CONCLUSION: Only two pregnant women born after the preventive program implementation were HBsAg-positive. Perinatal HBV transmission is estimated to be almost completely inhibited in the next generation.

Predicting future blood supply and demand in Japan with a Markov model: application to the sex- and age-specific probability of blood donation.

BACKGROUND: Simulation studies were performed to predict the future supply and demand for blood donations, and future shortfalls. STUDY DESIGN AND METHODS: Using data from all donations in 2006 to 2009, the Markov model was applied to estimate future blood donations until 2050. Based on data concerning the actual use of blood products, the number of blood products needed was estimated based on future population projections. RESULTS: We estimated that the number of blood donations increased from 5,020,000 in 2008 to 5,260,000 in 2012, but will decrease to 4,770,000 units by 2025. In particular, the number of donors in their 20s and 30s decreased every year. Moreover, the number of donations required to supply blood products would have been increased from 5,390,000 in 2012 to 5,660,000 units in 2025. Thus, the estimated shortfall of blood donations is expected to increase each year from 140,000 in 2012 to 890,000 in 2025 and then more than double to 1,670,000 in 2050. CONCLUSION: If the current blood donation behaviors continue, a shortfall of blood availability is likely to occur in Japan. Insufficient blood donations are mainly related to a projected reduction in population of 20 to 30 year olds, a significant group of donors. Thus, it is crucial to recruit and retain new donors and to develop recommendations for proper use of blood products to minimize unnecessary use. This study provides useful information that can be used by governments to help ensure the adequacy of the blood supply through promoting donations and conserving blood resources.

[Epidemiology of Hepatitis Virus Infection and Its Control from the Epidemiological Point of View.]

In Japan, hepatitis and liver cancer measures, based on the hepatitis Basic Measures Law, have been pro- moted for 25 years with a focus on advancing the diagnosis, treatment, and inspection. In 2011, the estimated number of people persistently infected with the hepatitis virus in Japan was esti- mated to be about 2.1-2.8 per million people. In addition, "persistent infections latent in society of people unaware of their infection" has been estimated to involve 777,000 people. Since it is now a time of introducing new drugs for effective anti-viral therapy, in order to continue to more effectively implement the hepatitis and liver cancer measures, regional cooperation, such as the construction of a liver disease patient follow-up system, is important.

Estimated numbers of patients with liver disease related to hepatitis B or C virus infection based on the database reconstructed from medical claims from 2008 to 2010 in Japan.

AIM: To estimate the number of patients with liver-related diseases classified by hepatitis viruses (HBV, HCV) based on the information from re-coded medical claims including several diagnosed diseases. METHODS: We analyzed reimbursement data provided by health insurance societies for 2.1 million individuals during 2008-2010. Database information of employees and their families aged under 65 years employees with hepatitis-related disease was extracted, the 1-year period prevalence was calculated, and then number of patients with liver disease related to HBV and HCV by sex and age groups, respectively, was estimated. RESULTS: The estimated number of patients were almost equivalent during 2008-2010. As for HBV and HCV, the estimated numbers of patients with chronic hepatitis (CH) in a year ranged 192 641-226 601 and 282 438-306 877, respectively. CONCLUSION: In the 2008 Patient Survey in Japan, the number of patients was estimated by the main disease in one patient, even though the patient was diagnosed with several diseases. Based on the database with hepatitis-related diseases after evaluating several diagnosed diseases from medical claims, the estimation method and protocol may minimize the disadvantage of medical claim analysis, and is useful for patients, especially asymptomatic carriers and those with CH which had been underestimated in the 2008 Patient Survey.

High prevalences of hepatitis B and C virus infections among adults living in Binh Thuan province, Vietnam.

AIM: Vietnam is one of the countries with the highest mortality from liver cancer, which is mostly attributed to hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. For planning preventive strategies against these infections, we investigated prevalences of HBV and HCV infections among adults living in Binh Thuan, Vietnam. METHODS: Our study consisted of a serological survey for HBV and HCV infections and a questionnaire survey on their risk factors. The sample size was calculated based on anticipated rate of hepatitis B surface antigen (HBsAg). Subjects were randomly sampled using a multistage method. Confirmation and family-tree surveys were conducted to examine persistent HBV infection and intrafamilial HBV transmission, respectively. RESULTS: A total of 509 adults, comprised of 230 men (45.2%) and 279 women (54.8%), were enrolled. Prevalences of HBsAg, hepatitis B surface antibody and hepatitis B core antibody were 15.3%, 60.3% and 71.7%, respectively. Most HBV DNA positive sera were classified as genotype B (75.3%) and C (11.7%). Of HBsAg positive subjects, 96.7% were persistently infected and one acutely HBV infected person was identified. Family-tree surveys suggested that horizontal extrafamilial HBV transmission might have been frequent. Prevalences of anti-HCV and HCV RNA were 3.3% and 1.8%, respectively. HCV genotype 6a was prominent (55.6%). CONCLUSION: In Binh Thuan, prevalences of HBV and HCV infections are high, HBV genotype B and HCV genotype 6a are predominant, and horizontal HBV transmission may still occur. Therefore, raising the coverage of a universal HBV vaccination program may be an effective liver cancer control in Vietnam.

Hepatitis B virus infection in hemodialysis patients in Japan: Prevalence, incidence and occult hepatitis B virus infection.

AIM: A survey of hepatitis B virus (HBV) infection in hemodialysis (HD) patients was conducted to determine the burden and risk of infection and to suggest preventive measures against HBV infection among HD patients at nine hospitals in Hiroshima, Japan, from 1999 to 2003. METHODS: HBV markers were investigated for 1860 HD patients. The prevalence, incidence of HBV and prevalence of occult HBV were calculated. RESULTS: The prevalence of hepatitis B surface antigen (HBsAg) was 2.6%, the positive rate of anti-hepatitis B core (HBc) was 20.6% and that of anti-hepatitis B surface (HBs) was 11.7%. Among 1372 patients who started HD after the approval of erythropoietin in Japan in 1991, the prevalence of HBsAg was 2.1%. The incidence rate of HBsAg positivity was 0/1000 person-years and the incidence of anti-HBc was 0.3/1000 person-years. Among 1812 HBsAg negative patients HBV DNA was detected in two: one case was negative for anti-HBc and anti-HBs, and the other was only positive for anti-HBc. Prevalence of occult HBV was 0.11%. CONCLUSION: The incidence rate of HBV was much lower than that of hepatitis C virus (HCV) in the same cohort. We supposed that the discrepancy between incidence rate of HBV and that of HCV was caused by the difference of their carrier rates and of their characteristics for persistent infection. So, we concluded that it is prerequisite to grasp the burden of HBV carriers in the group to prevent new HBV infections in HD patients.

Seroprevalence, genotypic distribution and potential risk factors of hepatitis B and C virus infections among adults in Siem Reap, Cambodia.

AIM: We investigated hepatitis B virus (HBV) and hepatitis C virus (HCV) infections among adults in Siem Reap, Cambodia, to consider the prevention strategy in cooperation with the Ministry of Health in Cambodia. METHODS: Serological tests for determining HBV and HCV infections and questionnaires were performed from 2010 to 2012 among the general population in the province of Siem Reap. Multivariate logistic regression analysis was conducted to clarify the factors related to HBV and HCV infections. RESULTS: There were 483 participants, comprising 194 men and 289 women (age range, 18-89 years). The prevalence of hepatitis B surface antigen was not very high at 4.6%, while anti-hepatitis B core (anti-HBc) was high at 38.5%. All HBV DNA samples were classified as genotype C. Anti-HBc showed the trend that the older the age, the higher the positive rate (P = 0.0002). The prevalence of HCV RNA and anti-HCV were 2.3% and 5.8%, respectively. HCV RNA was detected in 39.3% of anti-HCV positive samples and most of them were classified as genotype 6 (54.5%) and 1 (27.3%). Remarkably, in multivariate logistic regression analysis, history of operation and blood transfusion were significantly associated with the positivity for HBV infection and HCV RNA, respectively. CONCLUSION: Our results showed that operation and blood transfusion were potential risk factors for HBV and HCV infection, respectively, and supposed that horizontal HBV transmission may be frequent in adults in Cambodia. Hence, for reducing HBV and HCV infections, it is necessary to improve the safety of blood and medical treatment.

Validation and limitation of age-period-cohort model in simulating mortality due to hepatocellular carcinoma from 1940 to 2010 in Japan.

AIM: We aimed to simulate the mortality due to hepatocellular carcinoma (HCC) by the age-period-cohort (APC) model with use of sex- and age-specific mortality data, for the purpose of validating the utility and assessing the limitation of this model. METHODS: Age-specific mortality due to HCC was gleaned from people aged 20-84 years during 1940 through 2010 in Japan. RESULTS: The APC model had a high performance in reproducing HCC mortality (modified determination coefficient R(2) COR ≥ 0.99). Risk of HCC increased with age in both sexes, while risk of period barely changed in both sexes. The birth cohort factor in the APC model in males highlighted the maximum point within birth years 1931-1935. The observed HCC mortality in 2010 in males (19 444) was lower than the predicted, and corresponded to 72.3% of the predicted 26 883.4, and in all age groups by 5-year increments (55.6-90.9%). In females, the observed mortality was lower than that predicted in those aged 64 years or less, but not in those aged 65 years or more. CONCLUSION: We applied the APC model to predict HCC mortality rate, and it reproduced the observed mortality rate faithfully. However, in the recent past, the observed morality rate in males was only 72.3% that of the predicted. Such differences would be attributed to combined effects of medical interventions, such as antiviral treatments and screening for hepatitis viruses implemented in the early 1990s in Japan.