Data linkage to national Australian health insurance data to investigate exposure to environmental hazards: the example of residential asbestos

Introduction The enrolment data for Medicare, the Australian universal health insurance provider, covers almost the entire population. Medicare data are commonly used for data linkage, usually to access national medical and pharmaceutical data. However, the enrolment data also enable the identification of geographical cohorts for studies analysing exposure to environmental hazards. Objectives and Approach One example of this was the ACT Asbestos Health Study examining the health risks associated with living in houses insulated with loose-fill asbestos in the Australian Capital Territory. The Medicare Enrolment File contains the personal details and addresses of all people enrolled since 1984, including all updates to these details. We linked these data to a register of ~1100 affected properties, with subsequent linkage to the national death index and the Australian Cancer Database. We estimated Standardized Incidence Ratios (SIR) for selected cancers in people living in these houses to obtain a measure of exposure to environmental risk within the population. Results After intensive cleaning and standardisation, nearly all (99.8%) of the affected addresses were linked. There were over one million people who had at least one ACT address between 1983 and 2013, and 2% of these had lived at an affected address and classified as exposed. The adjusted incidence of mesothelioma in exposed males was 2·5 times that of unexposed males (SIR 2·54, 95% CI 1·02–5·24), and there were some statistically significant results. The study population, number of deaths and cancers of interest were validated against the ACT census and registry figures. There were some limitations in coverage due to the period of available data, the frequency of address updates, and records with postal rather than residential addresses, but these were tested by sensitivity analyses. Conclusion/Implications The study demonstrates the power of data linkage to (a) obtain a measure of exposure to an environmental risk within a population, and (b) obtain outcomes for the resulting case and control cohorts. This method could be applied in other risk studies where exposure is based on geography

Risk of cancer associated with residential exposure to asbestos insulation: a whole-population cohort study

Background The health risks associated with living in houses insulated with asbestos are unknown. Loose-fill asbestos was used to insulate some houses in the Australian Capital Territory (ACT). We compared the incidence of mesothelioma and other cancers in residents of the ACT who did and did not live in these houses. Methods Our cohort study included all ACT residents identified using Medicare enrolment data. These data were linked to addresses of affected residential properties in the ACT to ascertain exposure. We followed up residents by linking data to the Australian Cancer Database and National Death Index. Outcomes were diagnosis of mesothelioma and selected other cancers. Effects were estimated for males and females separately using standardised incidence ratios (SIRs), adjusting for age and calendar time of diagnosis. Findings Between Nov 1, 1983, and Dec 31, 2013, 1 035 578 ACT residents were identified from the Medicare database. Of these, 17 248 (2%) had lived in an affected property, including seven (2%) of 285 people diagnosed with mesothelioma. The adjusted incidence of mesothelioma in males who had lived at an affected property was 2·5 times that of unexposed males (SIR 2·54, 95% CI 1·02–5·24). No mesotheliomas were reported among females who had lived at an affected property. Among individuals who had lived at an affected property, there was an elevated incidence of colorectal cancer in women (SIR 1·73, 95% CI 1·29–2·26) and prostate cancer in men (1·29, 1·07–1·54); colorectal cancer was increased, although not significantly, in males (SIR 1·32, 95% CI 0·99–1·72), with no significant increase in the other cancers studied. Interpretation Residential asbestos insulation is likely to be unsafe. Our findings have important health, social, financial, and legal implications for governments and communities in which asbestos has been used to insulate houses.This work was funded by the ACT Government

Cancer risk in 680 000 people exposed to computed tomography scans in childhood or adolescence: Data linkage study of 11 million Australians

Objective To assess the cancer risk in children and adolescents following exposure to low dose ionising radiation from diagnostic computed tomography (CT) scans. Design Population based, cohort, data linkage study in Australia. Cohort members 10.9 million people identified from Australian Medicare records, aged 0-19 years on 1 January 1985 or born between 1 January 1985 and 31 December 2005; all exposures to CT scans funded by Medicare during 1985-2005 were identified for this cohort. Cancers diagnosed in cohort members up to 31 December 2007 were obtained through linkage to national cancer records. Main outcome Cancer incidence rates in individuals exposed to a CT scan more than one year before any cancer diagnosis, compared with cancer incidence rates in unexposed individuals. Results 60 674 cancers were recorded, including 3150 in 680 211 people exposed to a CT scan at least one year before any cancer diagnosis. The mean duration of follow-up after exposure was 9.5 years. Overall cancer incidence was 24% greater for exposed than for unexposed people, after accounting for age, sex, and year of birth (incidence rate ratio (IRR) 1.24 (95% confidence interval 1.20 to 1.29); P<0.001). We saw a dose-response relation, and the IRR increased by 0.16 (0.13 to 0.19) for each additional CT scan. The IRR was greater after exposure at younger ages (P<0.001 for trend). At 1-4, 5-9, 10-14, and 15 or more years since first exposure, IRRs were 1.35 (1.25 to 1.45), 1.25 (1.17 to 1.34), 1.14 (1.06 to 1.22), and 1.24 (1.14 to 1.34), respectively. The IRR increased significantly for many types of solid cancer (digestive organs, melanoma, soft tissue, female genital, urinary tract, brain, and thyroid); leukaemia, myelodysplasia, and some other lymphoid cancers. There was an excess of 608 cancers in people exposed to CT scans (147 brain, 356 other solid, 48 leukaemia or myelodysplasia, and 57 other lymphoid). The absolute excess incidence rate for all cancers combined was 9.38 per 100 000 person years at risk, as of 31 December 2007. The average effective radiation dose per scan was estimated as 4.5 mSv. Conclusions The increased incidence of cancer after CT scan exposure in this cohort was mostly due to irradiation. Because the cancer excess was still continuing at the end of follow-up, the eventual lifetime risk from CT scans cannot yet be determined. Radiation doses from contemporary CT scans are likely to be lower than those in 1985-2005, but some increase in cancer risk is still likely from current scans. Future CT scans should be limited to situations where there is a definite clinical indication, with every scan optimised to provide a diagnostic CT image at the lowest possible radiation dose

ACT Asbestos Health Study: Data Linkage Study on the Risk of Mesothelioma and Other Cancers in Residents of Affected Properties in the ACT

The Australian Capital Territory (ACT) Government commissioned the Australian National University to undertake a study to improve understanding of the health risks of loose-fill asbestos insulation, which was installed in over one thousand Canberra residences between 1968 and 1979. These affected residential properties (ARPs) are commonly referred to as ‘Mr Fluffy’ houses. This report concerns the fourth and final component of the ACT Asbestos Health StudyThis report was commisioned by The Lancet Public Healt

ACT Asbestos Health Study

The ACT Asbestos Health Study examined the health effects of living in a house with loose-fill asbestos insulation in the ACT. The study provided information on domestic exposure to loose-fill asbestos in the ACT and on the health concerns of current and recent residents of Mr Fluffy houses. It also reported on mesothelioma incidence in the ACT, and if data allowed it, provide estimates of the risk of mesothelioma and other cancers associated with living in an affected residence. The study was in response to multiple health forums held in 2014 with concerned residents of Mr Fluffy houses. There are 1,022 known residential properties affected by loose fill ‘Mr Fluffy’ amosite asbestos insulation in the ACT. While the mesothelioma rate is low in the ACT, at around 10 cases per year, concerns were raised by residents about the potential health impacts associated with living and in some cases, renovating, loose-fill asbestos homes.ACT Government. ACT Health and the ACT Asbestos Health Study Steering Committee.Protocols / Martyn Kirk, Rosemary Korda, Cathy Banwell, Phil Batterham, Mark Clements & Bruce Armstrong -- Vol. 1. Descriptive Study of Mesothelioma in the Australian Capital Territory / Rosemary J. Korda, Mark S. Clements, Bruce K. Armstrong,Susan M. Trevenar & Martyn D. Kirk-- Vol. 2. Focus Group Discussions / Cathy Banwell, Ginny Sargent, Susan M. Trevenar & Martyn D. Kirk -- Vol. 3. Cross Sectional Survey Report / Martyn D. Kirk, Philip J. Batterham, Mark S. Clements, Bruce K. Armstrong, Susan M. Trevenar, Jennifer A. Welsh & Rosemary J. Korda-- Vol. 4.1. Data Linkage Study on the Risk of Mesothelioma and Other Cancers in Residents of Affected Properties in the ACT / Rosemary J. Korda1, Mark S. Clements, Bruce K. Armstrong, Hsei Di Law, Tenniel Guiver, Philip R. Anderson, Susan M. Trevenar & Martyn D. Kirk -- Vol 4.2 Q &

Risk of cancer associated with residential exposure to asbestos insulation: a whole-population cohort study

Summary: Background: The health risks associated with living in houses insulated with asbestos are unknown. Loose-fill asbestos was used to insulate some houses in the Australian Capital Territory (ACT). We compared the incidence of mesothelioma and other cancers in residents of the ACT who did and did not live in these houses. Methods: Our cohort study included all ACT residents identified using Medicare enrolment data. These data were linked to addresses of affected residential properties in the ACT to ascertain exposure. We followed up residents by linking data to the Australian Cancer Database and National Death Index. Outcomes were diagnosis of mesothelioma and selected other cancers. Effects were estimated for males and females separately using standardised incidence ratios (SIRs), adjusting for age and calendar time of diagnosis. Findings: Between Nov 1, 1983, and Dec 31, 2013, 1â035â578 ACT residents were identified from the Medicare database. Of these, 17â248 (2%) had lived in an affected property, including seven (2%) of 285 people diagnosed with mesothelioma. The adjusted incidence of mesothelioma in males who had lived at an affected property was 2·5 times that of unexposed males (SIR 2·54, 95% CI 1·02â5·24). No mesotheliomas were reported among females who had lived at an affected property. Among individuals who had lived at an affected property, there was an elevated incidence of colorectal cancer in women (SIR 1·73, 95% CI 1·29â2·26) and prostate cancer in men (1·29, 1·07â1·54); colorectal cancer was increased, although not significantly, in males (SIR 1·32, 95% CI 0·99â1·72), with no significant increase in the other cancers studied. Interpretation: Residential asbestos insulation is likely to be unsafe. Our findings have important health, social, financial, and legal implications for governments and communities in which asbestos has been used to insulate houses. Funding: ACT Government