Search

Background: Helicobacter pylori is one of the most common human infections in the world, and studies in Alaska Native people, as well as other Indigenous peoples, have shown a high prevalence of this gastric infection. This study was undertaken to determine the prevalence of H. pylori infection by urea breath test (UBT) and anti- H. pylori IgG among Alaskans living in four regions of the state and to identify factors associated with infection., Methods: A convenience sample of persons > 6 months old living in five rural and one urban Alaskan community were recruited from 1996 to 1997. Participants were asked about factors possibly associated with infection. Sera were collected and tested for anti- H. pylori IgG antibodies; a UBT was administered to participants > 5 years old., Results: We recruited 710 people of whom 571 (80%) were Alaska Native and 467 (66%) were from rural communities. Rural residents were more likely to be Alaska Native compared with urban residents (P < .001). Of the 710 people, 699 (98%) had a serum sample analyzed, and 634 (97%) persons > 5 years old had a UBT performed. H. pylori prevalence was 69% by UBT and 68% by anti- H. pylori IgG. Among those with a result for both tests, there was 94% concordance. Factors associated with H. pylori positivity were Alaska Native racial status, age ≥ 20 years, rural region of residence, living in a crowded home, and drinking water that was not piped or delivered., Conclusions: Helicobacter pylori prevalence is high in Alaska, especially in Alaska Native persons and rural residents. Concordance between UBT and serology was also high in this group. Two socioeconomic factors, crowding and drinking water that was not piped or delivered, were found to be associated with H. pylori positivity., (© 2018 John Wiley & Sons Ltd.)

Background & Aims: Alaska Native people have an increased rate of hepatocellular carcinoma compared to the United States population. Viral hepatitis is a risk factor for malignancy and the leading cause of hepatocellular carcinoma in Alaska. With the introduction of hepatitis B immunization in 1982, as well as the emergence of hepatitis C virus in this population, the epidemiology and aetiology of hepatocellular carcinoma in Alaska have changed., Methods: Using the Alaska Native Tumor Registry, all cases of viral and non-viral hepatocellular carcinoma occurring from 1969 through 2013 were identified and reviewed. Incidence rates per 100 000 population were calculated for hepatocellular carcinoma overall and by aetiological category., Results: One hundred and fifty-two cases of hepatocellular carcinoma were identified in 148 Alaska Native persons. Overall tumour rate was 3.82 per 100 000 and did not change significantly over the study period. Hepatitis B-associated cases decreased significantly over the study period (P = 0.048) and were eliminated in persons under the age of 20. Hepatitis C-associated cases increased significantly (P < 0.001). Undetermined hepatocellular carcinoma rates also decreased (P = 0.034)., Conclusions: Overall hepatocellular carcinoma rates in Alaska Native people remained stable over the study period, but the epidemiology and aetiology are changing. Two decades after routine hepatitis B immunization, the hepatocellular carcinoma age distribution has shifted to cases presenting later in life. This is consistent with an ageing hepatitis B-infected population with no new infected young persons' coming into the population, as well as the emergence of hepatitis C in adults., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background & Aims: Most regions of the world have ≤3 co-circulating hepatitis B virus (HBV) genotypes, which limits direct comparisons of hepatocellular carcinoma (HCC) risk among HBV-infected persons by genotype. We evaluated HCC incidence by HBV genotype in a cohort of Alaska Native (AN) persons where five HBV genotypes (A, B, C, D, F) have been identified., Methods: Our cohort comprised AN persons with chronic HBV infection identified during 1983-2012 who consented to participate in this study. Cohort persons were offered annual hepatitis B e antigen (HBeAg) testing and semi-annual HCC screening. We developed a logistic regression model to compare HCC risk by genotype, adjusting for age, sex, region and HBeAg status., Results: Among the 1235 consenting study participants, 711 (57.6%) were male, 510 (41.3%) were HBeAg positive at cohort entry and 43 (3.5%) developed HCC. The HBV genotype was known for 1142 (92.5%) persons (13.5% A, 3.9% B, 6.7% C, 56.9% D, 19.0% F). The HCC incidence/1000 person-years of follow-up for genotypes A, B, C, D and F was 1.3, 0, 5.5, 0.4 and 4.2 respectively. Compared with persons with HBV genotype B/D infection, the HCC risk was higher for persons with genotypes A [adjusted odds ratio (aOR): 3.9, 95% confidence interval (CI): 1.14-13.74], C (aOR: 16.3, 95% CI: 5.20-51.11) and F (aOR: 13.9, 95% CI: 5.30-36.69)., Conclusion: HBV genotype is independently associated with HCC risk. AN persons with genotypes A, C and F are at higher risk compared with genotypes B or D., Competing Interests: None of the authors have any relevant conflicts of interest to disclose., (Published 2016. This article is a U.S. Government work and is in the public domain in the USA.)

This review summarizes studies on the epidemiology of Helicobacter pylori published in peer-reviewed journals between April 2007 and March 2008. Infection with H. pylori often occurs in childhood, and once established, can persist lifelong if untreated. Prevalence of H. pylori infection is higher in developing countries when compared to developed countries, and can vary by ethnicity, place of birth, and socioeconomic factors even among persons living in the same country. Prevalence of infection is decreasing in many countries due to improvements in sanitation and living standards and the relatively recent movement of populations from rural to urban settings; however, post-treatment recurrence rates of H. pylori infection remain high in developing countries, and in given populations within developed countries. In addition, a number of recent studies have begun to explore the possible link between childhood infection with H. pylori and protection against asthma and allergy.

Background: Previous studies in Alaska have demonstrated elevated proportions of antimicrobial resistance among Helicobacter pylori isolates., Materials and Methods: We analyzed H. pylori data from the Centers for Disease Control and Prevention (CDC)'s sentinel surveillance in Alaska from July 1999 to June 2003 to determine the proportion of culture-positive biopsies from Alaska Native persons undergoing routine upper-endoscopy, and the susceptibility of H. pylori isolates to metronidazole [minimum inhibitory concentration (MIC) of > 8 g metronidazole/mL), clarithromycin (MIC > or = 1), tetracycline (MIC > or = 2) and amoxicillin (MIC > or = 1)] using agar dilution., Results: Nine-hundred sixty-four biopsy specimens were obtained from 687 participants; 352 (51%) patients tested culture positive. Mean age of both culture-positive and culture-negative patients was 51 years. Metronidazole resistance was demonstrated in isolates from 155 (44%) persons, clarithromycin resistance from 108 (31%) persons, amoxicillin resistance from 8 (2%) persons, and 0 for tetracycline resistance. Metronidazole and clarithromycin resistance varied by geographic region. Female patients were more likely than male subjects to show metronidazole resistance (p < .01) and clarithromycin resistance (p = .05)., Conclusions: Resistance to metronidazole and clarithromycin is more common among H. pylori isolates from Alaska Native persons when compared with those from elsewhere in the USA.

Background/aims: An estimated one-third of patients with chronic hepatitis C virus (HCV) infection have persistently normal alanine transaminase (PNALT); however, in many previous studies alanine aminotransferase (ALT) levels were followed for < or = 12 months., Methods: We analyzed data from a population-based cohort of 935 Alaska Natives with HCV, recruited from 1994 to 2005, to determine the proportion of persons with PNALT, persistently elevated ALT (PEALT), and fluctuating ALT (FLUXALT) to determine factors for each ALT state. We selected persons with two positive HCV RNA results > or = 1 year apart and > or = 6 ALT levels measured over the subsequent 3 years with at least 1 month between ALT measurements (n = 265). We defined a person as having PNALT, PEALT, or FLUXALT when all six ALT levels were normal, elevated, or did not fit either of the above two categories, respectively, during the 3-year follow-up period., Results: Among 208 persistently HCV RNA-positive persons, 13 had PNALT, 121 PEALT, 74 FLUXALT. Among 77 persons who underwent liver biopsy, those with PEALT were more likely to have Ishak fibrosis scores > 2 compared with persons with FLUXALT (44% vs. 10%, OR 7.0, 95% CI: 1.5-33.2). No statistically significant differences were found in ALT classification by age, gender, infection duration, median body mass index, alcohol consumption, residence, risk behavior, RNA level, or genotype., Conclusions: Only 6% of persons with chronic HCV had PNALT. Persons with PEALT were significantly more likely to have higher fibrosis scores on liver biopsy than those with FLUXALT. Previous studies with short follow-up periods may have overestimated the proportion of persons with normal ALT levels.

Background: Limited information exists regarding risk factors for reinfection after cure of Helicobacter pylori infection., Aim: To determine the 2-year reinfection rate of H. pylori in a cohort of urban Alaska Natives., Methods: Participants over 18 years of age undergoing oesophagogastroduodenoscopy had (13)C urea breath test, culture, CLOtest and histology performed. Those diagnosed with H. pylori who tested urea breath test-negative at 8 weeks after treatment were followed prospectively at 4 months, 6 months, 1 year and 2 years. Subjects experiencing H. pylori reinfection as defined by a positive urea breath test were compared with those who did not become reinfected using univariable and multivariable analysis. Risk of reinfection over time was estimated by the Kaplan-Meier method., Results: Helicobacter pylori reinfection occurred in 14 of 98 subjects successfully treated. The cumulative reinfection rate was 5.1% (95% CI: 0.7%-9.5%) at 4 months, 7.2% (2.0-12.3%) at 6 months, 10.3% (4.2-16.3%) at 1-year and 14.5% (7.5-21.6%) at 2 years. In multivariable analysis, a history of previous peptic ulcer disease or presence of ulcer at time of study oesophagogastroduodenoscopy were the only risk factors associated with reinfection (P = 0.01)., Conclusions: Based on the findings from our study, subjects with a history of or current peptic ulcer disease should be followed, after successful treatment for H. pylori, with periodic urea breath test to detect reinfection, as reinfection would put them at high risk for ulcer recurrence.