Cervical abnormalities are more common among Indigenous than other Australian women: a retrospective record-linkage study, 2000–2011

Indigenous Australian women have much higher incidence of cervical cancer compared to non-Indigenous women. Despite an organised cervical screening program introduced 25 years ago, a paucity of Indigenous-identified data in Pap Smear Registers remains. Prevalence of cervical abnormalities detected among the screened Indigenous population has not previously been reported. We conducted a retrospective cohort study of population-based linked health records for 1,334,795 female Queensland residents aged 20–69 years who had one or more Pap smears during 2000–2011; from linked hospital records 23,483 were identified as Indigenous. Prevalence was calculated separately for Indigenous and non-Indigenous women, for cytology-detected low-grade (cLGA) and high-grade abnormalities (cHGA), and histologically confirmed high-grade abnormalities (hHGA). Odds ratios (OR) were estimated from logistic regression analysis. In 2010–2011 the prevalence of hHGA among Indigenous women (16.6 per 1000 women screened, 95% confidence interval [CI] 14.6–18.9) was twice that of non-Indigenous women (7.5 per 1000 women screened, CI 7.3–7.7). Adjusted for age, area-level disadvantage and place of residence, Indigenous women had higher prevalence of cLGA (OR 1.4, CI 1.3–1.4), cHGA (OR 2.2, CI 2.1–2.3) and hHGA (OR 2.0, CI 1.9–2.1). Our findings show that Indigenous women recorded on the Pap Smear Register have much higher prevalence for cLGA, cHGA and hHGA compared to non-Indigenous women. The renewed cervical screening program, to be implemented in 2017, offers opportunities to reduce the burden of abnormalities and invasive cancer among Indigenous women and address long-standing data deficiencies. Funding: LJ Whop is supported by a Sidney Myer Health Scholarship, Menzies Enhanced Living Top-up and a student scholarship funded by the Lowitja Institute. J Cunningham was supported by a National Health & Medical Research Council (NHMRC) Research Fellowship [#1058244]. PC Valery was supported by a NHMRC Career Development Fellowship [#1083090]. A Diaz is supported by a National Health and Medical Research Council (NHMRC) Training Scholarship for Indigenous Australian Health Research (No. 1055587). The National Indigenous Cervical Screening Project is funded by a NHMRC Project Grant [#104559]. This study was undertaken under the auspices of the Centre of Research Excellence in Discovering Indigenous Strategies to improve Cancer Outcomes Via Engagement, Research Translation and Training (DISCOVER-TT CRE, funded by the NHMRC [#1041111]), and the Strategic Research Partnership to improve Cancer control for Indigenous Australians (STREP Ca-CIndA, funded through Cancer Council NSW [SRP 13-01] with supplementary funding from Cancer Council WA). We also acknowledge the ongoing support of the Lowitja Institute, Australia's National Institute for Aboriginal and Torres Strait Islander Health Research. The views expressed in this publication are those of the authors and do not necessarily reflect the views of the funding agencies. Funding bodies have no role in the study design, data collection, access, analysis or interpretation or decision to publish.