Anna Törner

Non‐Hodgkin's lymphoma and other nonhepatic malignancies in Swedish patients with hepatitis C virus infection

The aim of this study was to evaluate the association between hepatitis C virus (HCV) infection and non‐Hodgkins lymphoma (NHL), multiple myeloma (MM), thyroid cancer (TC), chronic lymphatic leukemia (CLL), acute lymphatic leukemia (ALL), and Hodgkins lymphoma (HL). A Swedish cohort of 27,150 HCV‐infected persons notified during 1990‐2000 was included in the study. The database was linked to other national registers to calculate the observation time, expressed as person‐years, and to identify all incident malignancies in the cohort. The patients were stratified according to assumed time of previous HCV infection. The relative risk of malignancy was expressed as a standardized incidence ratio (SIR)—the observed number compared to the expected number. During 1990‐2000 there were 50 NHL, 15 MM, 14 ALL, 8 TC, 6 CLL, and 4 HL diagnoses in the cohort. Altogether, 20 NHL, 7 MM, 5 TC, 4 CLL, 1 ALL, and 1 HL patient fulfilled the criteria to be included in the statistical analysis. The observation time was 122,272 person‐years. The risk of NHL and MM was significantly increased in the stratum with more than 15 years of infection (SIR 1.89 [95% CI, 1.10‐3.03] and 2.54 [95% CI, 1.11‐5.69], respectively). The association was not significant in TC or CLL. In conclusion, we report the incidence of several malignancies in a nationwide cohort of HCV‐infected persons. Although the delayed diagnosis of HCV probably has resulted in an underestimation of the risk, this study showed a significantly increased risk of NHL and MM. (HEPATOLOGY 2005;41:652–659.)

Short- and Long-term Effects of Bacterial Gastrointestinal Infections

Bacterial gastrointestinal infections are associated with short- and long-term complications from several organ systems.

Risk factors for domestic sporadic campylobacteriosis among young children in Sweden

A case-control study was conducted in Sweden to study risk factors for domestically acquired Campylobacter jejuni/coli infections among children aged less than 6 y. A total of 126 cases, reported to the national surveillance system were recruited over 1 y. Controls, selected from the population register, were matched to the cases by age, gender, place of residence and time of infection of the case. Information was gathered by posted questionnaires. Two separate conditional regression models were developed including and excluding ‘protective’ factors. Two of the factors significantly associated with Campylobacter infection were water-related: having a well in the household (OR=2.6) and drinking water from a lake/river (OR=7.4; 6.0). Other exposures associated with increased risk were: having a dog (OR=8.4; 3.8) and eating grilled meat (OR=5.5; 2.1). Drinking unpasteurized milk was borderline significant in 1 model (OR=3.7). Eating sausage was protective (OR=0.05). Eating chicken was not a significant risk. Exposures such as eating grilled meat and drinking water from a lake or a river were more common in the warm months, a factor that may partly explain the observed seasonality. The authors suggest that differences between risk factors across studies may reflect geographical and age-specific differences in the sources of infection.

Cause of death in individuals with chronic HBV and/or HCV infection, a nationwide community‐based register study

Summary.  Studies on chronic viral hepatitis and mortality have often been made on selected populations or in high‐endemic countries. The aim of this study was to investigate the causes of death and the mortality rates in the nationwide cohorts of people chronically infected with hepatitis B virus (HBV) and/or hepatitis C virus (HCV) in Sweden, a low‐endemic country. All notifications on chronic HBV infection and HCV infection 1990–2003 were linked to the Cause of Death Register. A total of 9517 people with chronic HBV infection, 34 235 people with HCV infection and 1601 with chronic HBV–HCV co‐infection were included, and the mean observation times were 6.4, 6.3 and 7.9 years, respectively. The mortality in the cohorts was compared with age‐ and gender‐specific mortality in the general population and standardized mortality ratios (SMR) were calculated. All‐cause mortality was significantly increased, SMR 2.3 (HBV), 5.8 (HCV) and 8.5 (HBV–HCV), with a great excess liver‐related mortality in all cohorts, SMR 21.7, 35.5 and 46.2, respectively. In HCV and HBV–HCV infected there was an increased mortality due to drug‐related psychiatric diagnoses (SMR: 20.7 and 27.6) and external causes (SMR: 12.4 and 11.4), predominantly at younger age. To conclude, this study demonstrated an increased all‐cause mortality, with a great excess mortality from liver disease, in all cohorts. In people with HCV infection the highest excess mortality in younger ages was from drug‐related and external reasons.

Emergence and Spread of Chlamydia trachomatis Variant, Sweden

A variant of Chlamydia trachomatis that had escaped detection by commonly used systems was discovered in Sweden in 2006. In a nationwide study, we found that it is now prevalent across Sweden, irrespective of the detection system used. Genetic analysis by multilocus sequence typing identified a predominant variant, suggesting recent emergence.

A phase I clinical study of a live attenuated Bordetella pertussis vaccine--BPZE1; a single centre, double-blind, placebo-controlled, dose-escalating study of BPZE1 given intranasally to healthy adult male volunteers.

Background Acellular pertussis vaccines do not control pertussis. A new approach to offer protection to infants is necessary. BPZE1, a genetically modified Bordetella pertussis strain, was developed as a live attenuated nasal pertussis vaccine by genetically eliminating or detoxifying 3 toxins. Methods We performed a double-blind, placebo-controlled, dose-escalating study of BPZE1 given intranasally for the first time to human volunteers, the first trial of a live attenuated bacterial vaccine specifically designed for the respiratory tract. 12 subjects per dose group received 103, 105 or 107 colony-forming units as droplets with half of the dose in each nostril. 12 controls received the diluent. Local and systemic safety and immune responses were assessed during 6 months, and nasopharyngeal colonization with BPZE1 was determined with repeated cultures during the first 4 weeks after vaccination. Results Colonization was seen in one subject in the low dose, one in the medium dose and five in the high dose group. Significant increases in immune responses against pertussis antigens were seen in all colonized subjects. There was one serious adverse event not related to the vaccine. Other adverse events were trivial and occurred with similar frequency in the placebo and vaccine groups. Conclusions BPZE1 is safe in healthy adults and able to transiently colonize the nasopharynx. It induces immune responses in all colonized individuals. BPZE1 can thus undergo further clinical development, including dose optimization and trials in younger age groups. Trial Registration ClinicalTrials.gov NCT01188512

A Nationwide Cohort Study of Mortality Risk and Long-Term Prognosis in Infective Endocarditis in Sweden

Objectives: Infective endocarditis (IE) remains a serious disease with substantial mortality. In this study we investigated the incidence of IE, as well as its associated short and long term mortality rates. Methods The IE cases were identified in the Swedish national inpatient register using ICD-10 codes, and then linked to the population register in order to identify deaths in the cohort. Crude mortality rates among IE patients were obtained for different time intervals. These rates were directly standardized using sex- and age-matched mortality in the general population. Results The cohort consisted of 7603 individuals and 7817 episodes of IE during 1997–2007. The 30 days all-cause crude mortality rate was 10.4% and the standardized mortality ratio (SMR) was 33.7 (95% confidence interval [CI]: 31.0–36.6). Excluding the first year of follow-up, the long term mortality (1–5 years) showed an increased SMR of 2.2 (95% CI: 2.0–2.3) compared to the general population. Significantly higher SMR was found for cases of IE younger than 65 years of age with a 1–5 year SMR of 6.3, and intravenous drug-users with a SMR of 19.1. Native valve IE cases, in which surgery was performed had lower crude mortality rates and Mantel-Haenzel odds ratios of less than one compared to those with medical therapy alone during 30-day and 5-years follow-up. Conclusions The 30-days crude mortality rate for IE was 10.4% and long-term relative mortality risk remains increased even up to 5 years of follow-up, therefore a close monitoring of these patients would be of value.

Hepatocellular carcinoma and other primary liver cancers in hepatitis C patients in Sweden - a low endemic country.

Summary.  The aim of this study was to assess the risk of hepatocellular carcinoma (HCC) and other primary liver cancers (PLC) in the nationwide cohort of hepatitis C virus (HCV) infected patients in Sweden. The basis was the total HCV‐cohort notified in 1990–2004, after excluding 3238 people also reported with hepatitis B, the study cohort consisted of 36 126 people contributing an observation time of 246 105 person‐years. The most common route of transmission was intravenous drug use (57%). The national Cancer Registry was used for follow‐up, and 354 developed PLC (mainly HCC), of whom 234 were eligible for statistical analysis. The PLC incidence in the HCV cohort was compared with the incidence in the general population, and a standardized incidence ratio (SIR) was calculated for six different strata according to estimated duration of infection. The highest relative risk, SIR: 46 (95% CI: 36–56) was found in the stratum 25–30 years with HCV infection and SIR: 40 (95% CI: 31–51) in the stratum 30–35 years with infection. In the entire community‐based HCV cohort in Sweden we found a highly increased risk of liver cancer compared to the general population. The highest relative risk was among people who had been infected for more than 25 years.

Risk of kidney cancer and chronic kidney disease in relation to hepatitis C virus infection: a nationwide register-based cohort study in Sweden

Chronic hepatitis C virus (HCV) infection is an established cause of liver cancer, and recent studies have suggested a link with kidney cancer. The aim of this study was to evaluate risk of kidney cancer in relation to HCV infection in a nationwide registry-based study of Swedish residents diagnosed with HCV between 1990 and 2006. A total of 43 000 individuals with chronic HCV infection were included, and the mean follow-up time was 9.3 years. Observed kidney cancer incidence and mortality in the cohort were compared with expected values based on the age-adjusted and sex-adjusted rates in the general population. Risk of hospitalization for other chronic kidney disease was also evaluated using Cox proportional hazards regression. No association between HCV infection and risk of kidney cancer was observed [standardized incidence ratio with 1-year lag=1.2; 95% confidence interval (CI): 0.8–1.7]. Risk of hospitalization for noncancer kidney disease was significantly elevated in the HCV cohort, with significantly stronger associations observed among women than among men [hazard ratio=5.8 (95% CI: 4.2–7.9) and 3.9 (95% CI: 3.2–4.8) for women and men, respectively]. Results of this study do not support the hypothesis that chronic HCV infection confers an increased risk of kidney cancer. However, we did find an association between HCV infection and chronic kidney disease, particularly among women. Given inconsistent findings in the literature, it is premature to consider HCV infection to be a risk factor for kidney cancer.

Risk of pancreatic cancer among individuals with hepatitis C or hepatitis B virus infection: a nationwide study in Sweden

Background:A few studies indicated that hepatitis C and hepatitis B virus (HCV/HBV) might be associated with pancreatic cancer risk. The aim of this nationwide cohort study was to examine this possible association.Methods:Hepatitis C virus- and hepatitis B virus-infected individuals were identified from the national surveillance database from 1990 to 2006, and followed to the end of 2008. The pancreatic cancer risk in the study population was compared with the general population by calculation of Standardized Incidence Ratios (SIRs), and with a matched reference population using a Cox proportional hazards regression model to calculate hazard ratios (HRs).Results:In total 340 819 person-years in the HCV cohort and 102 295 in the HBV cohort were accumulated, with 34 and 5 pancreatic cancers identified, respectively. The SIRHCV was 2.1 (95% confidence interval, CI: 1.4, 2.9) and the SIRHBV was 1.4 (0.5, 3.3). In the Cox model analysis, the HR for HCV infection was 1.9 (95% CI: 1.3, 2.7), diminishing to 1.6 (1.04, 2.4) after adjustment for potential confounders.Conclusion:Our results indicated that HCV infection might be associated with an increased risk of pancreatic cancer but further studies are needed to verify such association. The results in the HBV cohort indicated an excess risk, however, without statistical significance due to lack of power.