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Background/Aims: Hepatocellular carcinoma (HCC) incidence has increased in Australia in the past 20-30 years. We conducted a community-based linkage study to examine the characteristics of hepatocellular carcinoma with particular reference to hepatitis B and (3 infections. Methods: Hepatocellular carcinoma cases (n=2,072) notified to the New South Wales (NSW) Central Cancer Registry from 1990 to 2002 were probabilistically linked to HBV and HCV diagnoses notified to NSW Health. Sex, age, year of diagnosis, region of birth, method of diagnosis and spread at diagnosis and survival were compared by linkage group. Results: Hepatocellular carcinoma incidence increased from 1.4/100,000 in 1990 to 2.8/100,000 in 2002. Incidence varied by region of birth (p Conclusion: Contrasting age distribution of HCV-related HCC by country/region of birth is consistent with divergent patterns of HCV transmission. Implications: These data highlight the increase in HCC in NSW and the divergent populations whose needs in terms of treatment, care and prevention will need to be met. Key words: Carcinoma; hepatocellular; hepatitis B; hepatitis C; data linkage.

Objective: To assess the sensitivity and specificity of linkage of HIV/AIDS diagnoses in Australia to the National Death Index (NDI). Methods: An aggregated file containing 19,772 matched HIV/AIDS diagnoses reported to the national HIV/AIDS databases from 1980 to 30 June 2004 was linked to the NDI using probabilistic linkage methods based on the namecode, date of birth, and sex as identifiers. Based on the 6,900 HIV/AIDS known deaths reported by 1 January 2003 and 1,455 known non-deaths with an active follow-up beyond 1 January 2003, the different combinations of weights assigned to matched pairs were examined to obtain maximum sensitivity and specificity. Results: The trade-off between sensitivity and specificity was used to obtain an optimal linkage. The optimal linkage was found to link 5,668 of the 6,900 HIV/AIDS known deaths (a sensitivity of 82%), and 116 false positives of the 1,455 known not deaths (specificity of 92%). Causes of deaths were recorded for 86.5% of deaths that were linked to the NDI. Conclusion: This is a feasible method for conducting linkage studies if both the identifying deaths and non-deaths are available. The relatively poor sensitivity could be due to limited identifiers available for linkage on the HIV/AIDS databases. Key words: Data linkage; mortality; National Death Index; sensitivity; specificity. (Aust NZ J Public Health. 2007; 31:308-12) doi:10.1111/j.1753-6405.2007.00076.x

Objective: The effectiveness of the National Death Index (NDI) in identifying deaths among different populations has been studied before. Prisoners represent a segment of the population that might be expected to be difficult to link. The objective of this research was to evaluate the accuracy of the Australian NDI to ascertain the mortality status of prisoners in New South Wales, Australia. Methods: Data on 311 inmates who had died in custody between January 1988 and March 2003, and on 7,558 inmates known to be alive at the end of May 2003, were matched to the NDI database. Matching was undertaken using a probabilistic linkage method followed by a clerical review. The underlying causes of death reported by the NDI were compared against those reported by the NSW Coroner and held at the Legal Branch of the Department of Corrective Services. Results: Linkage correctly identified 275 of the 311 known deaths (sensitivity: 88.4%). Of the 7,558 prisoners known to be alive in custody at the end of May 2003, linkage to the NDI incorrectly identified 23 as dead (specificity: 99.7%). Cause of death was accurately reported by the NDI for 95.5% of deaths identified by the linkage. Conclusion: The results of this study show that the NDI is an accurate and feasible means for evaluating mortality among prisoners. The nature of the prisoner population makes the linkage a difficult task for the NDI. The success of the data linkage depends on the extent and accuracy of information contained in the index file and type and quality of information available.

Objectives: To assess whether workers at Lucas Heights Science and Technology Centre (LHSTC) have different levels of mortality from the New South Wales (NSW) and Australian populations. Methods: A retrospective cohort study was undertaken at LHSTC. Data on 7,076 workers employed between 1957-98 were abstracted from personnel, dosimetry, and medical files. Deaths registrations in the cohort were identified to 1998 through electronic linkage of records with NSW and national registers of cancer incidence and mortality. Two inception cohorts were defined as including 4,717 and 3,543 workers in employment between 1972-98 and 1980-98, to examine cancer mortality and all-cause mortality respectively. Results: All-cause mortality was 31% lower than the national rates; all-cancer mortality was 19% below the NSW rate. Of 37 specific cancers and groups of cancers examined, statistically significant excesses relative to NSW rates were observed only for pleural cancer mortality (SMR=21.11; 95% CI 8.79-50.72). Conclusions: The observed increase in the risk of cancer of the pleura was probably due to unmeasured exposures, given the lack of an established association with radiation exposure and the strong link to asbestos exposure.

Objectives: To estimate the prevalence of chronic hepatitis B virus (HBV) infection in Australia and attributable proportions associated with specific demographic groups at higher risk of infection. Methods: Two methods were used to estimate prevalence of HBV surface antigen (HBsAg): (1) Population-based: results of a national serosurvey using sera collected opportunistically from laboratories across Australia were used for 1-59 year olds, with the HBsAg prevalence for 50-59 years extrapolated to the population aged 60 years and over; (2) Risk group-based: estimates for selected high-risk groups (injecting drug users, homosexual men, Indigenous Australians and people born in high-prevalence countries), using source data from antenatal HBV screening in central Sydney, HBV prevalence studies, and estimates for low-risk groups (first-time blood donors) were combined preportionally to their representation in the population. Results: Prevalence of HBsAg in the national serosurvey increased, with age, from 0.0% for 1-4 and 5-9 year olds to 1.3-1.8% for the 40-49 year age group. Australian population HBsAg prevalence based on minimum and adjusted estimates from this serosurvey were 91,500 (0.49%) and 163,000 (0.87%)infections, respectively. The risk group method estimated an Australian HBsAg prevalence of 88,000 infections (0.47%). Approximately 50% of people with chronic HBV infection were estimated to be immigrants from either South-East Asia (33.3%) or North-East Asia (16.2%). Conclusion: The range of estimates for chronic HBV infection in Australia is broad, reflecting the uncertainty in source data. A national blood survey encompassing a large and representative population sample may help to provide more accurate estimates A large proportion of people with chronic HBV infection are Asian born.

Incidence of human immunodeficiency virus (HIV) infection in a cohort of homosexually active men has been studied in Sydney, Australia. The HIV incidence decreased in the cohort over time, being a 9.6% in 1984 and 5.0 % in 1986, but low from 1987, 1.9%, to 1994, 0.0%. Incidence of infection was higher in those under 34 years of age at enrollment and those who reported 4+ sexual partners in the 6 months before enrollment. Those associations disappeared by 1987.