Chronic hepatitis B in children in Gothenburg, Sweden

Risk of hepatocellular carcinoma and cancers at other sites among patients diagnosed with chronic hepatitis B virus infection in Sweden

Hepatitis B virus (HBV) infection is one of most common viral infections worldwide. While chronic HBV infection has been shown consistently to be associated with hepatocellular carcinoma, data on associations with cancers at other sites are limited. In this study a total of 10,197 patients were diagnosed with chronic HBV infection in Sweden, and they were retrieved from the nationwide Swedish Hospital Discharge Register and Outpatient Register and linked to Cancer Registry data. Standardized incidence ratios (SIRs) for cancers were calculated for these patients in comparison with the population without HBV infection. Five hundred sixty-seven of whom developed cancer (SIR 1.82 (95% confidence interval (CI) 1.67-1.97)) during the study period. The SIR for hepatocellular carcinoma in patients with HBV infection was 40.58 (95% CI 30.50-50.07). In addition, a total of seven other cancer sites/types showed increased SIRs: cancers of the upper aerodigestive tract, lung, kidney, skin (squamous cell carcinoma), and thyroid gland, and lymphoma and leukemia. The risks of non-Hodgkin lymphoma and acute myeloid leukemia were increased in both Swedish- and foreign-born patients with HBV infection. In summary, chronic HBV infection is a strong risk factor for hepatocellular carcinoma and also increases the risk of seven other cancers. These findings illustrate the need for surveillance for cancers other than hepatocellular carcinoma in patients with HBV infection.

Hepatocellular carcinoma in individuals with HBV infection or HBV-HCV co-infection in a low endemic country

OBJECTIVE

The aim of this nationwide cohort study was to assess the risk for hepatocellular carcinoma (HCC) in patients with chronic hepatitis B virus (HBV) infection or HBV and hepatitis C virus (HCV) co-infection in Sweden, a low endemic country.

MATERIAL AND METHODS

A total of 12,080 patients with HBV and 3238 patients with HBV-HCV co-infection were notified to the Swedish institute for Infectious Disease Control between 1990 and 2004. After excluding 1850 patients with acute HBV and 584 patients infected in adult life, we analyzed the cohort of 9646 subjects with chronic HBV infection. In the co-infection cohort, 1697 patients were analyzed after excluding 1541 cases with acute HBV. The Swedish national cancer registry was used for follow-up. The HCC incidence rate in the cohorts was compared with the HCC incidence rate in the general population and the standardized incidence ratio (SIR) was calculated for different strata according to estimated infection period.

RESULTS

HCC was found in 45 patients in the HBV cohort. In the stratum of 40-49 years of infection we found a SIR of 47 and in stratum 50-59 years the SIR was 54. In the co-infected cohort 10 HCCs were found. The SIR in the stratum 20-29 years of infection was 34 and the SIR in the stratum 30 years and over was 91.

CONCLUSIONS

This national cohort study of HBV infected and HBV-HCV co-infected subjects in a low endemic country confirms a highly increased risk of liver cancer compared to the general population.

Liver and gallbladder cancer in immigrants to Sweden

BACKGROUND

The changes of cancer incidence upon immigration can be used as an estimator of environmental influence on cancer risk. We studied site-specific liver and biliary cancers in first-generation immigrants to Sweden with an aim to search for aetiological clues and to find evidence for indigenous incidence rates.

MATERIAL AND METHODS

We used the nation-wide Swedish Family-Cancer Database to calculate standardised incidence ratios (SIRs) in immigrants compared to native Swedes.

RESULTS

A total of 1428 cancers were identified in immigrants whose median ages (years) at immigration were 27 for men and 26 for women and whose median diagnostic ages were 64 and 66, respectively. The highest SIRs of 6.7 for primary liver cancer were observed for men from East Asia and sub-Saharan Africa. Increased SIRs were recorded for male immigrants from previous Yugoslavia (1.78), Southern Europe (2.91), Turkey (2.15) and Asian Arab countries (2.89). For gallbladder cancer, only women from the Indian subcontinent (3.84) and Chile (2.34) had increased risk while some Northern European immigrants showed decreased risks.

CONCLUSIONS

Primary liver cancer was increased in immigrants from endemic regions of hepatitis B virus infection but also from large regions lacking cancer incidence data, North Africa, Asian Arab countries, Turkey and previous Yugoslavia; these are probably intermediary risk regions for this infection. The consideration of these regions as risk areas would justify active diagnostic and vaccination programs. The increase in gallbladder cancer in Chileans and Indians suggests that some persistent damage was inflicted before emigration, characterisation of which will be a challenge for aetiological studies.

Population mobility and infectious diseases: the diminishing impact of classical infectious diseases and new approaches for the 21st century

In an increasingly globalized world, rapid population mobility and migration is reducing the differences in infectious disease epidemiology between regions of the world. The movement and relocation of populations between locations where the prevalence and incidence of infections are markedly different poses current and future challenges to those involved in clinical infectious diseases and public health program management. Historically, international attention has focused on the screening and treatment of acute infections of epidemic potential, but, as immigration significantly changes the demography of many nations, chronic infections will require increased attention. In countries with large mobile populations, the population-based burden of infections with long latency periods or significant noninfectious sequelae will make up an increasing amount of the infectious disease caseload and will require more-modern approaches than the traditional screening of arrivals. The globalization of chronic infectious disease epidemiology will require corresponding development of integrated programs to anticipate and manage these diseases in response to an increasingly mobile patient population.