[Truncated abstract. Please see pdf format for complete text.] Background : The excess burden of mortality born by young Indigenous Australians and the disparity in infant and childhood mortality between Indigenous and non-Indigenous Australians have been well documented. The accuracy and completeness of national data describing the health of Indigenous Australians is inconsistent. The Western Australia (WA) Maternal and Child Health Research Database (MCHRDB), is a linked total population database that includes perinatal maternal and infant data, and infant and childhood morbidity and mortality data. Overall, these data are more than 99% complete, with a similar high level of completeness and validity for Indigenous Western Australians. Aim : The aim of this thesis is to measure Indigenous infant (0 to <1 year) and childhood (>=1 to <19 years) mortality and the disparity between Indigenous and non-Indigenous infants and children in WA for birth cohorts from 1980 to 1997 inclusive. To achieve this aim a number of secondary aims were identified, including the measurement of certain maternal and infant variables, and the age-specific, all-cause and cause-specific mortality for WA infants and children. Method : The study comprises a longitudinal birth cohort study, the primary data source being the MCHRDB. Data included on the MCHRDB are complete for all births in WA from 1980 onwards, with new birth cohorts linked on an annual basis. Maternal and infant variables and the geographical location of the residence and the time of birth and death were included in the descriptive and multivariate analyses. Each infant and childhood death was coded using a three-digit code developed primarily for research purposes. The descriptive analyses of mortality referred to the probability of dying in infancy and in childhood as the cumulative mortality risk (CMR), for various diseases and various population subgroups. Age-specific childhood rates were also calculated. The results of multivariate analyses included the fitting of Cox and Poisson regression models, and estimates of effect were represented as hazard ratios (Cox regression) and relative rates (Poisson regression). Results : Between 1980 and 1997, births to Indigenous mothers accounted for 6% of total WA births. Approximately 46% of Indigenous births were to mothers living in a remote location compared to 9% of non-Indigenous births. Indigenous mothers gave birth at an earlier age (30% of births were to teenage mothers compared to 6% of non-Indigenous births), and were more likely to be single than non-Indigenous mothers (40% Indigenous, 9% non-Indigenous). Indigenous infants had more siblings, were born at an earlier gestation and with a lower birth weight and percentage of expected birth weight. The CMR for Indigenous infants was 22 per 1000 live births compared with 6.7 for non- Indigenous infants, a relative risk (RR) of 3.3 (95%CI 3.0, 3.6). While there was a decrease in the CMR over the birth year groups for both populations, the disparity between the rate of Indigenous and non-Indigenous infant mortality increased. The Indigenous postneonatal (>28 to 365 days) mortality rate (11.7 per 1,000 neonatal survivors) was higher than the neonatal (0 to 28 days) mortality rate (10.3 per 1,000 live births). This profile differed from that for non-Indigenous infants, where the neonatal mortality rate (4.3 per 1,000 live births) was nearly twice that of the postneonatal mortality rate (2.4 per 1,000 neonatal survivors). The main causes of infant mortality among Indigenous infants were potentially preventable. These causes were infection followed by Sudden Infant Death Syndrome (SIDS), which differed from the main causes for non-Indigenous infants, sequelae of prematurity and birth defects. The CMR attributable to SIDS increased over the years amongst Indigenous infants and decreased significantly over the years in the non-Indigenous population. Furthermore, the disparity in mortality between the two populations increased and, in 1995 to 1997, was over seven times higher amongst Indigenous infants. The CMR was highest amongst infants living in remote locations for all causes of death except for Indigenous deaths attributable to SIDS, where the risk of death was highest amongst infants living in metropolitan locations. With the exception of infection, there was no difference in cause-specific mortality amongst Indigenous infants according to geographical location. Indigenous infants living in a remote location were at a significantly increased risk of death due to infection compared with their peers living in a rural or metropolitan location. The risk of death for Indigenous children was more than three times higher than for non-Indigenous children. This risk was significantly increased when most of the perinatal maternal and infant variables were considered.
| Identifer | oai:union.ndltd.org:ADTP/220970 |
| Date | January 2003 |
| Creators | Freemantle, Cecily Jane |
| Publisher | University of Western Australia. School of Paediatrics and Child Health |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Cecily Jane Freemantle, http://www.itpo.uwa.edu.au/UWA-Computer-And-Software-Use-Regulations.html |
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