Definition and diagnosis of cerebral palsy in genetic studies: a systematic review.

AIM: To conduct a systematic review of phenotypic definition and case ascertainment in published genetic studies of cerebral palsy (CP) to inform guidelines for the reporting of such studies. METHOD: Inclusion criteria comprised genetic studies of candidate genes, with CP as the outcome, published between 1990 and 2019 in the PubMed, Embase, and BIOSIS Citation Index databases. RESULTS: Fifty-seven studies met the inclusion criteria. We appraised how CP was defined, the quality of information on case ascertainment, and compliance with international consensus guidelines. Seven studies (12%) were poorly described, 33 studies (58%) gave incomplete information, and 17 studies (30%) were well described. Missing key information precluded determining how many studies complied with the definition by Rosenbaum et al. Only 18 out of 57 studies (32%) were compliant with the Surveillance of Cerebral Palsy in Europe (SCPE) international guidelines on defining CP. INTERPRETATION: Limited compliance with international consensus guidelines on phenotypic definition and mediocre reporting of CP case ascertainment hinders the comparison of results among genetic studies of CP (including meta-analyses), thereby limiting the quality, interpretability, and generalizability of study findings. Compliance with the SCPE guidelines is important for ongoing gene discovery efforts in CP, given the potential for misclassification of unrelated neurological conditions as CP.

Parent perspectives on consent for the linkage of data to evaluate vaccine safety: a randomised trial of opt-in and opt-out consent.

BACKGROUND: We examined parents' consent preferences and understanding of an opt-in or opt-out invitation to participate in data linkage for post-marketing safety surveillance of childhood vaccines. METHODS: A single-blind parallel-group randomised controlled trial: 1129 families of babies born at a South Australian hospital in 2009 were sent information at 6 weeks post-partum, explaining data linkage of childhood immunisation and hospital records for vaccine safety surveillance, with 4 weeks to opt in or opt out by reply form, telephone, or email. At 10 weeks post-partum, 1026 (91%) parents were followed up by telephone interview. RESULTS: In both the opt-in (n = 564) and opt-out arms (n = 565), four-fifths of the parents recalled receiving the information (81% vs. 83%, P = 0.35), three-fifths reported reading it (63% vs. 67%, P = 0.11), but only two-fifths correctly identified the health records to be linked (43% vs. 39%, P = 0.21). Parents who actively consented (opted in) were more likely than those who passively consented (did not opt out) to recall the information (100% vs. 83%, P < 0.001), report reading it (94% vs. 67%, P < 0.001), and correctly identify the data sources (60% vs. 39%, P < 0.001). Most parents supported data linkage for vaccine safety surveillance (94%) and trusted its privacy protections (84%). Most parents wished to have minimal or no direct involvement, preferring either opt-out consent (40%) or no consent (30%). A quarter (24%) of parents indicated opt-in consent should be sought; of these, 8% requested consent prior to every use, 5% preferred to give broad consent just once and 11% preferred periodic renewal. Three-fifths of the parents gave higher priority to rapid vaccine safety surveillance (61%) rather than first seeking parental consent (21%), and one in seven was undecided (15%). Although 91% of parents reported that their babies were fully immunised (76%) or under-immunised (15%), and trusted vaccines as safe (90%), three-fifths (62%) were very or somewhat concerned about serious reactions. LIMITATIONS: The context of data linkage is limited to vaccine safety surveillance. Only recall and understanding retained at 1 month post enrolment were measured. CONCLUSIONS: This trial demonstrates that informed consent for a population-based surveillance programme cannot realistically be achieved using mail-based opt-in and opt-out approaches. While recall and understanding of the study's purpose were better among parents who actively consented (opted in) compared with parents who passively consented (did not opt out), participation was substantially lower (21% vs. 96% respectively). Most parents appeared to have a poor understanding of data linkage for vaccine safety surveillance; nonetheless, they supported data linkage. They preferred a system utilising opt-out consent or no consent to one using opt-in consent.

A randomised controlled trial to compare opt-in and opt-out parental consent for childhood vaccine safety surveillance using data linkage.

INTRODUCTION: No consent for health and medical research is appropriate when the criteria for a waiver of consent are met, yet some ethics committees and data custodians still require informed consent. METHODS: A single-blind parallel-group randomised controlled trial: 1129 families of children born at a South Australian hospital were sent information explaining data linkage of childhood immunisation and hospital records for vaccine safety surveillance with 4 weeks to opt in or opt out by reply form, telephone or email. A subsequent telephone interview gauged the intent of 1026 parents (91%) in relation to their actions and the sociodemographic differences between participants and non-participants in each arm. RESULTS: The participation rate was 21% (n=120/564) in the opt-in arm and 96% (n=540/565) in the opt-out arm (χ(2) (1 df) = 567.7, p<0.001). Participants in the opt-in arm were more likely than non-participants to be older, married/de facto, university educated and of higher socioeconomic status. Participants in the opt-out arm were similar to non-participants, except men were more likely to opt out. Substantial proportions did not receive, understand or properly consider study invitations, and opting in or opting out behaviour was often at odds with parents' stated underlying intentions. CONCLUSIONS: The opt-in approach resulted in low participation and a biased sample that would render any subsequent data linkage unfeasible, while the opt-out approach achieved high participation and a representative sample. The waiver of consent afforded under current privacy regulations for data linkage studies meeting all appropriate criteria should be granted by ethics committees, and supported by data custodians. TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trials Registry ACTRN12610000332022.

Head and traumatic brain injuries among Australian youth and young adults, July 2000-June 2006.

OBJECTIVES: To describe rates of hospitalization for head and traumatic brain injury (TBI) among Australian adults aged 15-24 years. DESIGN: Descriptive analysis of the Australian Institute of Health and Welfare National Hospital Morbidity Database, using data from 1 July 2000 to 30 June 2006. RESULTS: The rate of hospitalization for head injury was 618.5 per 100 000, with 148.1 per 100 000 being high threat to life injuries. In multivariate analysis, males had 3.2-times the rate of females. Youth and young adults living in remote and very remote areas had a 2.6-3.2-fold greater rate of head injury than city-dwellers and a 2.3-2.7-fold greater rate of injuries that were high threat to life. The rate of TBI was 169.3 per 100 000, with 87.1 per 100 000 being high threat to life injuries. In multivariate analysis, males had 3.2-times the rate of females. Youth and young adults living in very remote and remote areas had a 2.5-3.0-fold greater rate of TBI than city-dwellers and a 2.1-2.3-fold greater rate of high threat to life TBI. CONCLUSIONS: Males and youth and young adults living remotely were disproportionately represented among those sustaining head injuries. A quarter of hospitalized head injuries were coded as having TBI.

Head and traumatic brain injuries among Australian children, July 2000-June 2006.

OBJECTIVE: To describe the rates of hospitalisation for head and traumatic brain injury among Australian children aged 0-14 years. DESIGN: Descriptive analysis of the Australian Institute of Health and Welfare National Hospital Morbidity Database, using data for the period 1 July 2000 to 30 June 2006. RESULTS: The rate of hospitalisation for head injury was 395.9 per 100,000 (95% CI 393.4 to 398.4), with 47.6 per 100,000 (95% CI 46.7 to 48.5) being high-threat-to-life injuries. In multivariate analysis, those aged 0-4 years had 1.8 times the rate of head injury of 10-14-year-olds, while boys had 1.7 times the rate of girls. Children living in very remote and remote areas had a 1.3-1.5-fold greater rate of head injury, and a 1.6-1.8-fold greater rate of injuries that were high threat to life, than city-dwelling children. The rate of traumatic brain injury (TBI) was 91.1 per 100,000 (95% CI 89.9 to 92.3), with 34.7 per 100,000 (95% CI 33.9 to 35.4) being high-threat-to-life injuries. In multivariate analysis, children aged 0-4 years had 0.8 times the rate of 10-14-year-olds, and boys had 1.9 times the rate of girls. Children living in the very remote and remote areas had a 1.9-2.8-fold greater rate of TBI, and a 1.5-1.7-fold greater rate of injuries that were high threat to life, than city-dwelling children. CONCLUSIONS: Children living remotely were disproportionately represented among those sustaining head injuries. Almost a quarter of head injuries were TBI.

Mutations disrupting neuritogenesis genes confer risk for cerebral palsy.

In addition to commonly associated environmental factors, genomic factors may cause cerebral palsy. We performed whole-exome sequencing of 250 parent-offspring trios, and observed enrichment of damaging de novo mutations in cerebral palsy cases. Eight genes had multiple damaging de novo mutations; of these, two (TUBA1A and CTNNB1) met genome-wide significance. We identified two novel monogenic etiologies, FBXO31 and RHOB, and showed that the RHOB mutation enhances active-state Rho effector binding while the FBXO31 mutation diminishes cyclin D levels. Candidate cerebral palsy risk genes overlapped with neurodevelopmental disorder genes. Network analyses identified enrichment of Rho GTPase, extracellular matrix, focal adhesion and cytoskeleton pathways. Cerebral palsy risk genes in enriched pathways were shown to regulate neuromotor function in a Drosophila reverse genetics screen. We estimate that 14% of cases could be attributed to an excess of damaging de novo or recessive variants. These findings provide evidence for genetically mediated dysregulation of early neuronal connectivity in cerebral palsy.

Hospital admissions of indigenous and non-indigenous Australians due to interpersonal violence, July 1999 to June 2004.

OBJECTIVE: To compare the incidence of injury-related hospitalisations and the injury profiles for interpersonal violence, in the Indigenous and non-Indigenous populations of Australia. METHOD: Descriptive analysis of the National Hospital Morbidity Database (NHMD), using data for the Northern Territory, Western Australia, South Australia and Queensland for the period 1 July 1999 to 30 June 2004. RESULTS: Indigenous people were twice as likely as non-Indigenous people to be hospitalised for injury (age-standardised rate ratio [SRR] 2.26, 95% CI 2.24-2.29), and had a 17-fold greater hospitalisation rate for interpersonal violence (SRR, 16.9, 95% CI 16.6-17.3). Indigenous males and females were most commonly injured by a family member or intimate partner and females constituted 54% of Indigenous cases. Most non-Indigenous cases were males (82%), most commonly injured by stranger(s). Head injuries by bodily force were the most frequent injuries. Age-standardised hospitalisation rates of interpersonal violence increased with remoteness of usual residence for Indigenous people and, less so, for others. CONCLUSION: The largest differential between Indigenous and non-Indigenous injury-related hospitalisations was for interpersonal violence, particularly for women. About half the excess morbidity from interpersonal violence among Indigenous people is due to factors associated with remote living. IMPLICATIONS: Culturally appropriate interventions that tackle a wide range of social and economic issues are needed to mitigate Indigenous interpersonal violence.

Use of different combination diphtheria-tetanus-acellular pertussis vaccines does not increase risk of 30-day infant mortality. A population-based linkage cohort study using administrative data from the Australian Childhood Immunisation Register and the National Death Index.

OBJECTIVE: To determine whether differences in combination DTaP vaccine types at 2, 4 and 6 months of age were associated with mortality (all-cause or non-specific), within 30 days of vaccination. DESIGN: Observational nationwide cohort study. SETTING: Linked population data from the Australian Childhood Immunisation Register and National Death Index. PARTICIPANTS: Australian infants administered a combination trivalent, quadrivalent or hexavalent DTaP vaccine (DTaP types) between January 1999 and December 2010 at 2, 4 and 6 months as part of the primary vaccination series. The study population included 2.9, 2.6, & 2.3 million children in the 2, 4 and 6 month vaccine cohorts, respectively. MAIN OUTCOME MEASURES: Infants were evaluated for the primary outcome of all-cause mortality within 30 days. A secondary outcome was non-specific mortality (unknown cause of death) within 30 days of vaccination. Non-specific mortality was defined as underlying or other cause of death codes, R95 'Sudden infant death syndrome', R96 'Other sudden death, cause unknown', R98 'Unattended death', R99 'Other ill-defined and unspecified cause of mortality' or where no cause of death was recorded. RESULTS: The rate of 30 day all-cause mortality was low and declined from 127.4 to 59.3 deaths per 100,000 person-years between 2 and 6 month cohorts. When compared with trivalent DTaP vaccines, no elevated risk in all-cause or non-specific mortality was seen with any quadrivalent or hexavalent DTaP vaccines, for any cohort. CONCLUSION: Use of routine DTaP combination vaccines with differing disease antigens administered during the first six months of life is not associated with infant mortality.

Process trumps potential public good: better vaccine safety through linked cross-jurisdictional immunisation data in Australia.

OBJECTIVE: To provide insights into complexities of seeking access to state and federal cross-jurisdictional data for linkage with the Australian Childhood Immunisation Register (ACIR). We provide recommendations for improving access and receipt of linked datasets involving Australian Government-administered data. METHODS: We describe requirements for linking eleven federal and state data sources to establish a national linked dataset for safety evaluation of vaccines. The required data linkage methodology for integrating cross-jurisdictional data sources is also described. RESULTS: Extensive negotiation was required with 18 different agencies for 21 separate authorisations and 12 ethics approvals. Three variations of the 'best practice' linkage model were implemented. Australian Government approval requests spanned nearly four years from initial request for data, with a further year before ACIR data transfer to the linkage agency. CONCLUSIONS: Integration of immunisation registers with other data collections is achievable in Australia but infeasible for routine and rapid identification of vaccine safety concerns. Lengthy authorisation requirements, convoluted disparate application processes and inconsistencies in data supplied all contribute to delayed data availability. Implications for public health: Delayed data access for safety surveillance prevents timely epidemiological reviews. Poor responsiveness to safety concerns may erode public confidence, compromising effectiveness of vaccination programs through reduced participation.

Erratum: Author Correction: Pathogenic copy number variants that affect gene expression contribute to genomic burden in cerebral palsy.

[This corrects the article DOI: 10.1038/s41525-018-0073-4.].

Workers' drinking patterns: the impact on absenteeism in the Australian work-place.

AIMS: To examine the relationship between Australian workers' patterns of alcohol consumption and absenteeism. DESIGN: A secondary analysis of the 2001 National Drug Strategy Household Survey data. SETTING: Australia 2001. PARTICIPANTS: A total of 13 582 workers aged >or=14 years. MEASUREMENTS: Alcohol consumption levels associated with National Health and Medical Research Council (NHMRC) guidelines for short- and long-term harm were identified and compared with self-reported measures of absenteeism due to alcohol use and due to any illness/injury. FINDINGS: More than 40% of the Australian work-force consumed alcohol at risky or high-risk levels at least occasionally. High-risk drinkers were up to 22 times more likely to be absent from work due to their alcohol use compared to low-risk drinkers. Short-term high-risk drinkers were also significantly more likely to be absent from work due to any illness or injury than employed low-risk drinkers. Young employees and males were more likely to report alcohol-related absenteeism compared to older workers and females. CONCLUSIONS: The relationship between workers' alcohol consumption patterns and absenteeism is more substantial than previously recognized or documented. Alcohol-related absenteeism is not restricted to small numbers of chronic heavy drinkers, but also involves the much larger number of risky non-dependent drinkers who drink less frequently at risky levels. To improve workers' health and wellbeing and enhance productivity and economic prosperity, appropriate education, prevention and policy strategies are warranted and necessitate revision of previously narrow approaches undertaken with work-place programmes.

Pathogenic copy number variants that affect gene expression contribute to genomic burden in cerebral palsy.

Cerebral palsy (CP) is the most frequent movement disorder of childhood affecting 1 in 500 live births in developed countries. We previously identified likely pathogenic de novo or inherited single nucleotide variants (SNV) in 14% (14/98) of trios by exome sequencing and a further 5% (9/182) from evidence of outlier gene expression using RNA sequencing. Here, we detected copy number variants (CNV) from exomes of 186 unrelated individuals with CP (including our original 98 trios) using the CoNIFER algorithm. CNV were validated with Illumina 850 K SNP arrays and compared with RNA-Seq outlier gene expression analysis from lymphoblastoid cell lines (LCL). Gene expression was highly correlated with gene dosage effect. We resolved an additional 3.7% (7/186) of this cohort with pathogenic or likely pathogenic CNV while a further 7.7% (14/186) had CNV of uncertain significance. We identified recurrent genomic rearrangements previously associated with CP due to 2p25.3 deletion, 22q11.2 deletions and duplications and Xp monosomy. We also discovered a deletion of a single gene, PDCD6IP, and performed additional zebrafish model studies to support its single allele loss in CP aetiology. Combined SNV and CNV analysis revealed pathogenic and likely pathogenic variants in 22.7% of unselected individuals with CP.

Prevalence and patterns of alcohol use in the Australian workforce: findings from the 2001 National Drug Strategy Household Survey.

AIMS: To describe Australian workers' prevalence and patterns of alcohol use. DESIGN: A secondary analysis of the 2001 National Drug Strategy Household Survey. PARTICIPANTS: A total of 13 582 workers > or = 14 years old. MEASUREMENTS: Alcohol consumption levels associated with National Health and Medical Research Council (NHMRC) guidelines for short- and long-term harm were stratified by occupation and industry. FINDINGS: Approximately 8% of the workforce drank at least weekly at short-term risky or high risk levels, 17% drank at least monthly, 18% drank at least yearly and 11% drank at long-term risky or high risk levels. The prevalence of risky or high risk drinking was higher for younger than for older workers. Controlling for socio-demographic factors, the risk of workers frequently drinking at levels associated with short-term harm was lowest in the education industry and significantly higher in the hospitality, agriculture, manufacturing and construction industries. Drinking patterns associated with long-term harm were more prevalent in the agriculture, retail and manufacturing industries, compared to the education industry. Drinking patterns associated with both short- and long-term harm were more prevalent for blue-collar workers than professionals. CONCLUSIONS: Risky and high risk drinking occurred at least occasionally in 44% of Australian workers. Workers in the hospitality, agriculture, manufacturing, construction and retail industries, workers in blue-collar occupations and young workers were identified as at-risk subgroups. These data provide evidence that patterns of consumption differ between occupational and industry groups, and highlight the pressing need to develop policies, prevention and intervention strategies to reduce harmful alcohol use in Australia, particularly among young adults.

Cervical spinal cord injury in rugby union and rugby league: are incidence rates declining in NSW?

OBJECTIVES: To estimate trends in incidence rates of rugby code-related severe cervical spinal cord injuries in New South Wales (NSW) from 1986 to 2003. To evaluate the Australian Spinal Cord Injury Register (ASCIR) for injury surveillance by comparison with two published studies. METHODS: Data were cases of complete and incomplete tetraplegia in rugby union and rugby league admitted to the two spinal units in NSW. Trends in incidence rates were estimated using Poisson regression modelling. RESULTS: There was a small, non-significant decline from 1986 to 2003 in the incidence rate of tetraplegia in rugby union (9.8 vs. 6.1 per 100,000 player-years; p = 0.378) and rugby league (2.3 vs. 1.6 per 100,000 player-years; p = 0.564). The most common causes of injury were scrums for rugby union (35%) and tackles for rugby league (78%). This did not change over time (rugby union, p = 0.118; rugby league, p = 0.288). The ASCIR identified more cases of tetraplegia than insurance claims data and at least 75% of the cases ascertained by medical record review. CONCLUSIONS: There remains an urgent need to further improve safety in rugby union and rugby league. Scrummage in union and tackles in league remain the leading causes of tetraplegia. Rates of tetraplegia were significantly higher and more variable in rugby union than in rugby league. IMPLICATIONS: The ASCIR is a useful tool to monitor trends in spinal cord injury incidence in both rugby codes. Its potential value is constrained by the lack of accurate estimates of player numbers.

Consumer perceptions of safety in hospitals.

BACKGROUND: Studies investigating adverse events have traditionally been principally undertaken from a medical perspective. The impact that experience of an adverse event has on consumer confidence in health care is largely unknown. The objectives of the study were to seek public opinion on 1) the rate and severity of adverse events experienced in hospitals; and 2) the perception of safety in hospitals, so that predictors of lack of safety could be identified. METHODS: A multistage, clustered survey of persons residing in South Australia (2001), using household interviews (weighted n = 2,884). RESULTS: A total of 67% of respondents aged over forty years reported having at least one member of their household hospitalised in the past five years; with the average being two hospital admissions in five years. Respondents stated that 7.0% (95%CI: 6.2% to 7.9%) of those hospital admissions were associated with an adverse event; 59.7% of respondents (95% CI: 51.4% to 67.5%) rated the adverse event as really serious and 48.5% (95% CI: 40.4% to 56.8%) stated prolonged hospitalisation was required as a consequence of the adverse event. Perception of safety in hospitals was largely affected by the experience of an adverse event; really serious events were the most significant predictor of lack of safety in those aged 40 years and over (RR 2.38; p<0.001). CONCLUSION: The experience of adverse events negatively impacted on public confidence in hospitals. The consumer-reported adverse event rate in hospitals (7.0%) is similar to that identified using medical record review. Based on estimates from other studies, self-reported claims of adverse events in hospital by consumers appear credible, and should be considered when developing appropriate treatment regimes.

Public perspectives on consent for the linkage of data to evaluate vaccine safety.

INTRODUCTION: We sought community opinion on consent alternatives when linking childhood immunisation and hospital attendance records for the purpose of vaccine safety surveillance. METHODS: We conducted computer-assisted telephone interviewing (CATI) of a sample of rural and metropolitan residents of South Australia in 2011. RESULTS: Of 2002 households interviewed (response rate 55.6%), 96.4% supported data linkage for postmarketing surveillance of vaccines; very few were completely opposed (1.5%) or undecided (2.2%). The majority (75.3%) trusted the privacy protections used in data linkage and most wished to have minimal or no direct involvement, preferring either opt-out consent (40.4%) or no consent (30.6%). A quarter of respondents (24.6%) favoured opt-in consent, but their preferences were divergent; half requested consent be sought prior to every use (11.4%) while the remainder preferred to give broad consent just once (3.4%) or renewed at periodic intervals (9.8%). Over half of the respondents gave higher priority to rapid vaccine safety surveillance (56.5%) rather than first seeking parental consent (26.6%) and one in seven was undecided (14.5%). Although 91.6% of respondents believed childhood vaccines are safe, over half (53.1%) were very or somewhat concerned that a vaccine could cause a serious reaction. Nevertheless, 92.4% of the parents in the sample (556/601) reported every child in their care as being fully immunised according to the National Immunisation Program schedule. Only 3.7% of parents (22/601) reported one or more children as under immunised, and 3.9% (23/601) reported that none of their children were immunised. CONCLUSIONS: This survey demonstrates that data linkage for vaccine safety surveillance has substantial community support and that a system utilising opt-out consent or no consent was preferred to one using opt-in consent. These findings should inform public health policy and practice; data linkage should be established where feasible to address limitations in passive surveillance systems.

A randomised controlled trial to compare opt-in and opt-out parental consent for childhood vaccine safety surveillance using data linkage: study protocol.

BACKGROUND: The Vaccine Assessment using Linked Data (VALiD) trial compared opt-in and opt-out parental consent for a population-based childhood vaccine safety surveillance program using data linkage. A subsequent telephone interview of all households enrolled in the trial elicited parental intent regarding the return or non-return of reply forms for opt-in and opt-out consent. This paper describes the rationale for the trial and provides an overview of the design and methods. METHODS/DESIGN: Single-centre, single-blind, randomised controlled trial (RCT) stratified by firstborn status. Mothers who gave birth at one tertiary South Australian hospital were randomised at six weeks post-partum to receive an opt-in or opt-out reply form, along with information explaining data linkage. The primary outcome at 10 weeks post-partum was parental participation in each arm, as indicated by the respective return or non-return of a reply form (or via telephone or email response). A subsequent telephone interview at 10 weeks post-partum elicited parental intent regarding the return or non-return of the reply form, and attitudes and knowledge about data linkage, vaccine safety, consent preferences and vaccination practices. Enrolment began in July 2009 and 1,129 households were recruited in a three-month period. Analysis has not yet been undertaken. The participation rate and selection bias for each method of consent will be compared when the data are analysed. DISCUSSION: The VALiD RCT represents the first trial of opt-in versus opt-out consent for a data linkage study that assesses consent preferences and intent compared with actual opting in or opting out behaviour, and socioeconomic factors. The limitations to generalisability are discussed. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12610000332022.

Hospitalisation for head injury due to assault among Indigenous and non-Indigenous Australians, July 1999--June 2005.

OBJECTIVE: To describe rates of hospitalisation for head injury due to assault among Indigenous and non-Indigenous Australians. DESIGN, SETTING AND PARTICIPANTS: Secondary analysis of routinely collected hospital morbidity data for 42,874 inpatients at public and private hospitals in Queensland, Western Australia, South Australia and the Northern Territory for the 6-year period 1 July 1999--30 June 2005. MAIN OUTCOME MEASURES: Rates per 100,000 population of head injury due to assault by Indigenous status, age, sex and location of residence. RESULTS: The overall rate of head injury due to assault was 60.4 per 100,000 population (95% CI, 59.8-60.9). The rate among the Indigenous population was 854.8 per 100,000 (95% CI, 841.0-868.9), 21 times that among the non-Indigenous population (40.7 per 100,000; 95% CI, 40.2-41.2). Most Indigenous (88%) and non-Indigenous (83%) victims of head injury due to assault were aged between 15 and 44 years. The peak incidence among the Indigenous population was in the 30-34-year age group, whereas that among the non-Indigenous population was in the 20-24-year age group. Indigenous females experienced 69 times the injury rate experienced by non-Indigenous females. CONCLUSIONS: Indigenous people, particularly women, were disproportionately represented among those hospitalised for head injury due to assault. Head injury imposes a substantial burden of care on individuals and communities. Along with the costs of treating head injury, these are good reasons to strengthen efforts to prevent head injury generally, with special attention to high-risk population segments.