Sudden infant death syndrome and infant mortality in Aboriginal and non-Aboriginal infants

The aim of this study was to investigate sudden infant death syndrome (SIDS) in the context of total infant mortality for Aboriginal and non-Aboriginal infants. Deaths for infants born in Western Australia from 1980 to 1988 inclusive were ascertained from a total population data base. Infant mortality rates and rates by period and cause of death were calculated for both populations. Aboriginal infants had a mortality rate three times that for non-Aboriginal infants (23.6 cf. 7.9 per 1000 live births) and both populations showed a similar rate of decline in mortality over the study period. There were differences in the proportion of deaths occurring neonatally and postneonatally in the two populations. In terms of SIDS, 21% of the deaths in Aboriginal infants occurred neonatally compared with 7% for non-Aboriginal infants. The overall cause of infant death distribution differed significantly between the two populations ( P < 0.001). During the study period, Aboriginal infants showed a significant increase in deaths due to SIDS and a significant decrease in those due to birth defects and low birthweight. These results suggest it would be useful to review the pathology and diagnosis of sudden unexplained death in infancy.     

Postneonatal mortality in Western Australia 1970–78

ABSTRACT. Postneonatal deaths in Western Australia from 1970–78 were studied using a linked file of birth and death registrations. Postneonatal mortality fell during the period under study. The fall occurred in both male and female rates and the former were higher than the latter in all years. The infants at high risk during the postneonatal period were those born to unmarried teenage mothers residing in rural areas, especially if the infants were of low birthweight (<2500g). Multiple births and those infants born to mothers whose previous issues were over 4 were also at high risk. Infants born to Aboriginal mothers experienced a significantly higher rate of postneonatal mortality than those born to non-Aboriginal mothers. However, a significant improvement in the Aboriginal rate occurred between 1976 and 1977. The major causes of postneonatal death were sudden infant death syndrome, infections and congenital abnormalities.     

Sudden infant death syndrome and unascertainable deaths: trends and disparities among Aboriginal and non-Aboriginal infants born in Western Australia from 1980 to 2001 inclusive

AIM: To analyse patterns and trends in mortality from unknown causes (sudden infant death syndrome and unascertainable deaths) for all Aboriginal and non-Aboriginal infants born in Western Australia, 1980-2001. METHODS: Using total population linked data, we reviewed all post-mortem reports, including death scene investigations and final causes of death as ascertained by the coroner. Neonatal, post-neonatal and infant mortality rates attributed to unknown causes were calculated and the latter were analysed according to maternal age, geographical location, gestational age, sex and birthweight. Relative risks (95% confidence interval) for Aboriginal infants (compared with non-Aboriginal) were calculated. RESULTS: The proportion of deaths considered to be of unascertainable cause has significantly increased in recent years. In contrast to the non-Aboriginal population, there has been no significant decrease in deaths in the Aboriginal population and the overall relative risk for Aboriginal infants for the most recent years studied was 7.9 (95% confidence interval 5.1-12.2). The relative risk was significantly increased for most categories analysed. CONCLUSION: Reviewing post-mortem reports enabled identification of changes in the classification of deaths due to unknown causes. This provided a more accurate picture of the patterns and long-term trends of such deaths so that programmes can be developed to specifically target those groups most at risk. Adequately funded and evaluated education campaigns aimed at reducing the risk of sudden infant death syndrome among Aboriginal infants are required, as well as sustaining the current efforts that have been so successful for non-Aboriginal infants.     

Why do Aboriginal newborns weigh less? Determinants of birthweight for gestation

Objective : To compare birthweight for gestational age of Aboriginal with Caucasian infants and investigate the origins of their differences.
Methodology : Data pertaining to birthweight, gestational age at delivery and pathological factors were abstracted from birth records of 1301 Western Australian singleton Aboriginal pregnancies dated before 24 weeks by ultrasound fetometry and compared with routinely collected data pertaining to Caucasian births of the same period.
Results : Median birthweight for gestation was lower in Aboriginal than in Caucasian infants for deliveries after 35 weeks of gestation, and that of pure-descent lower than that of mixed-descent Aboriginal infants at all gestations. Pathological factors (e.g. diabetes, urogenital infections, alcoholism and leprosy) occurring more commonly in Aboriginal than in Caucasian pregnancies accounted for most of the differences in birthweight for gestation between mixed-descent Aboriginal and Caucasian infants but a discrepancy of almost 180 g remained between pure-descent Aboriginal and Caucasian infants.
Conclusions : Identified pathological factors contribute but do not entirely explain the lower birthweights for gestation observed in Aboriginal infants.     

Low birthweight and mortality in Australian Aboriginal babies at the Royal Darwin Hospital: A 15 year study

Abstract A retrospective analysis was made of all births at the Royal Darwin Hospital from 1 January 1969 to 31 December 1983. The births were divided into weight categories and racial groups (Aboriginal and non-Aboriginal).
The study showed that there was a 23.2% incidence of low birthweight (LBW) babies (less than 2500 g) in Aboriginals compared with an incidence of 6.4% in non-Aboriginals. It was found that Aboriginals had a better chance of surviving the neonatal periods than non-Aboriginals of the same birthweight for all birthweights up to 2500 g. It is suggested that this occurred because most LBW Aboriginals were more mature than their birthweight would have suggested.
The perinatal and neonatal mortality, however, remains high in the Aboriginal babies and this can also be attributed to the high incidence of LBW babies in this group, and perhaps to the limited use of antenatal care by the Aboriginal mothers.     

A pediatrician and his mothers and infants

Pediatricians are in a unique place in society by being able not only to care for the health and well-being of mothers and which, are their clinical responsibility, but also by being able to act as advocates for those patients who are often among the most vulnerable of our population. This article illustrates some of these points by referring to Australian Aboriginals from the vast desert areas of Westerns Australia. In remote areas of Western Australia, Aboriginal infants have high rates of low birth weight, failure to thrive and undernutrition. They also have high rates of respiratory, gastrointestinal and other infections. Aboriginal infant mortality has improved significantly over recent years, but Aboriginal health and mortality rates are still much worse than those of non-Aboriginal children and tend to be worst in more remote parts of the state. Overall, Aboriginal infants less than one year in age were hospitalized 9.5 times more frequently than non-Aboriginal infants for respiratory diseases (such as pneumonia, acute bronchiolitis and asthma); diarrheal diseases and skin infections were other very important causes of hospitalization for Aboriginal infants. Another poorly understood aspect of Aboriginal health is their widespread proneness to urinary tract infections. This is very important now in Australian Aboriginals in whom end-stage renal failure is becoming very prevalent. Rapid social and lifesyle changes have been very important in the poor health status of Aboriginals. They are also subject to severe socio-economic discrimination, underemployment, limited education, overcrowding, social depression and severely depressed housing conditions, relative inaccessibility to adequate and nutritious foodstuffs, and limited access to clinical services. Aboriginal people are prone to obesity, hypertension, type-2 diabetes mellitus and cardiovascular diseases. Overuse of alcohol and tobacco smoking have also become important challenges, particularly among adolescents and young adults. For the past twenty years or so, special programs have been developed to help overcome some of these problems; these include immunization programs, an extensive child health care program, special childhood screening programs, and oral rehydration therapy to reduce the high rates of mortality and morbidity associated with diarrheal diseases. These improvements have been achieved despite a set of socio-economic circumstances that face Aboriginal infants and children who live with adverse social factors. This was termed "Down and Out in 1996" in an editorial in The New Scientist (27 January 1996). A strategy that Australian Aboriginals are using now is to increase their own role through Aboriginal-controlled health and medical services including child health programs.     

Low birthweight and impaired growth to 5 years in Australian Aborigines

Abstract Twelve per cent of Aboriginal infants born in the Kimberley region of Western Australia in 1980 were of low birthweight; this is more than twice the incidence in the non-Aboriginal population of Western Australia. There was widespread faltering of growth (weight and height) after 6 months of age in Aboriginal children whether they were of normal or low birthweight. Growth retardation was more marked in low birthweight babies who showed little evidence of 'catch-up'growth in the first 5 years of life.     

Low birthweight and impaired growth to 5 years in Australian aborigines

Twelve per cent of Aboriginal infants born in the Kimberley region of Western Australia in 1980 were of low birthweight; this is more than twice the incidence in the non-Aboriginal population of Western Australia. There was widespread faltering of growth (weight and height) after 6 months of age in Aboriginal children whether they were of normal or low birthweight. Growth retardation was more marked in low birthweight babies who showed little evidence of 'catch-up' growth in the first 5 years of life.     

Postneonatal mortality in Western Australia 1970-1978

Postneonatal deaths in Western Australia from 1970-78 were studied using a linked file of birth and death registrations. Postneonatal mortality fell during the period under study. The fall occurred in both male and female rates and the former were higher than the latter in all years. The infants at high risk during the postneonatal period were those born to unmarried teenage mothers residing in rural areas, especially if the infants were of low birthweight (less than 2500g). Multiple births and those infants born to mothers whose previous issues were over 4 were also at high risk. Infants born to Aboriginal mothers experienced a significantly higher rate of postneonatal mortality than those born to non-Aboriginal mothers. However, a significant improvement in the Aboriginal rate occurred between 1976 and 1977. The major causes of postneonatal death were sudden infant death syndrome, infections and congenital abnormalities.     

Interpretation of recent sudden infant death syndrome rates in Western Australia

The diagnosis of sudden infant death syndrome (SIDS) has undergone several changes in definition since first being recognised as a cause of death. Linked total population data from Western Australia enable investigations to determine changes in classifications of mortality for the infants of Aboriginal and non-Aboriginal mothers (Aboriginal and Torres Strait Islander people are referred to throughout this report as 'Aboriginal'). Data for recent years show a shift away from a classification of 'SIDS' towards a classification of 'unascertainable', particularly for Aboriginal infants. This has implications for the accurate translation of data into policy and practice.     

Sudden infant death syndrome in Aboriginal and non-Aboriginal infants

This study, based on routinely recorded data, was designed to compare the epidemiology of sudden infant death syndrome (SIDS) in Aboriginal and non-Aboriginal infants in Western Australia (WA). All cases of SIDS occurring in infants born in WA from 1980 to 1988 were included in the study. There were 66 Aboriginal (6.1 per 1000 live births) and 337 non-Aboriginal (1.7 per 1000 live births) infants who died from SIDS. It was found that there was a significant linear increase in the Aboriginal SIDS rate over the study period while the non-Aboriginal rate remained relatively constant. For non-Aboriginal infants, there was an elevated risk of SIDS for young maternal age, single marital status and male gender but this was not found for Aboriginal infants. There was a significant difference in the age at death distribution for the two populations. Low birthweight and preterm birth were risk factors for both Aboriginal and non-Aboriginal infants. There may be differences in the aetiology and/or classification of SIDS between the two populations.     

Low birthweight and mortality in Australian Aboriginal babies at the Royal Darwin Hospital: a 15 year study

A retrospective analysis was made of all births at the Royal Darwin Hospital from 1 January 1969 to 31 December 1983. The births were divided into weight categories and racial groups (Aboriginal and non-Aboriginal). The study showed that there was a 23.2% incidence of low birthweight (LBW) babies (less than 2500 g) in Aboriginals compared with an incidence of 6.4% in non-Aboriginals. It was found that Aboriginals had a better chance of surviving the neonatal periods than non-Aboriginals of the same birthweight for all birthweights up to 2500 g. It is suggested that this occurred because most LBW Aboriginals were more mature than their birthweight would have suggested. The perinatal and neonatal mortality, however, remains high in the Aboriginal babies and this can also be attributed to the high incidence of LBW babies in this group, and perhaps to the limited use of antenatal care by the Aboriginal mothers.     

Hospital admissions in the first year of life in very preterm infants

OBJECTIVE: To analyse hospital readmissions to 1 year in infants < 33 weeks' gestation. STUDY DESIGN: Cohort of very preterm infants born in Western Australia. METHODS: Parental social class, history of asthma, race, gestational age, birthweight, sex, severity of respiratory disease and oxygen requirement at 28 days chronic lung disease (CLD), 36 weeks and term, maternal smoking, cohabitation with siblings, breast-feeding duration and hospital readmissions were recorded prospectively. RESULTS: Data were available for 538 of 560 (96%) infants discharged. Eight died in the first year. Two hundred and twenty-five infants (42%) had 443 readmissions, of which 370 were medical and 73 surgical. Risk factors for medical readmission were Aboriginal race, male sex and CLD. Breast-feeding was protective. Risk factors for surgical admission were male sex, lower gestation, severe hyaline membrane disease, severe CLD and birthweight < 10th centile. CONCLUSIONS: Readmission is common after very preterm birth. Risk factors for medical and surgical admission differ with CLD being the only perinatal factor associated with both medical and surgical admission.     

Is being Aboriginal or Torres Strait Islander a risk factor for poor neonatal outcome in a tertiary referral unit in north Queensland?

OBJECTIVE: To compare perinatal outcomes for all births, and the morbidity and mortality patterns of babies admitted to neonatal intensive care, for non-Indigenous, Aboriginal and Torres Strait Islander (TSI) people in a major remote urban centre. METHODS: A prospective cohort study of all births and consecutive admissions to the Neonatal Intensive Care Unit/Special Baby Care Unit (NICU/SCBU) at Kirwan Hospital for Women (KWH), Townsville (a tertiary referral hospital) was conducted from January 1998 to June 1999. RESULTS: There were 2575 births, with 2392 (93%) booked into KWH for delivery. The Aboriginal group differed from the non-Indigenous group only in the prevalence of low-birthweight births. The TSI group had significantly higher perinatal mortality rates, preterm and low-birthweight births than the non-Indigenous group. Seven hundred and fifty-eight babies were admitted to NICU/SCBU: 586 (77%) non-Indigenous, 129 (17%) Aboriginal, 43 (6%) TSI. There were significantly more preterm, lower birthweight and longer stay length Aboriginal and TSI babies. Being Indigenous was not associated with neonatal death. Gestation of less than 28 weeks, congenital anomalies, and high-grade cerebral haemorrhage, but not ethnicity, were independent risk factors for neonatal death. Maternal risk factors, including poor antenatal care attendance, were more prevalent amongst Indigenous women. CONCLUSION: Neonatal outcomes for Aboriginal infants were better than expected from national and State reports. Outcomes for Torres Strait Islander infants were worse than expected. Ethnicity was not a risk factor for neonatal death. These findings suggest that outcomes may be further improved by programmes to increase access for Indigenous women to antenatal care services.     

Respiratory distress syndrome in infants with impaired intrauterine growth

The recently introduced intrauterine growth curve, based on ultrasonically estimated foetal weights, was retrospectively applied to an inborn population of 883 infants bom before 33 gestational weeks at the University Hospital of Lund, during 1985–94. The estimation of birthweight deviation resulted in 630 (71.3%) infants with a birthweight appropriate for gestational age (AGA), 244 (27.6%) infants with a birthweight small for gestational age (SGA) and 9(1.1%) infants with a birthweight large for gestational age. Birthweight deviation was associated with an increased mortality [odds ratio (OR) adjusted for gestational age 1.29 per SD (12%) change in birthweight for gestational age, 95% CI: 1.10–1.50; p = 0.002]. At gestational age 25–28 weeks, SGA-infants had an increased incidence of respiratory distress syndrome (RDS) as compared to AGA-infants (OR adjusted for gestational age: 1.98,95% CI: 1.12–3.52; p = 0.019). At gestational age 29–32 weeks, SGA-infants had a lower incidence of RDS as compared to AGA-infants (OR adjusted for gestational age: OR 0.52,95% CI: 0.34–0.80; p = 0.003). After adjustment for confounding variables, infants born at gestational age 25–28 weeks from mothers with pre-eclampsia, appeared to be a high-risk group for RDS, whereas at the age of 29–32 gestational weeks, negative birthweight deviation had a protective effect against RDS. Antenatal corticosteroid administration appeared to have a less beneficial effect on mortality, RDS and cerebral haemorrhage in infants born SGA vs in those born AGA.     

Improved male neonatal outcome in Western Australia

Male neonatal mortality in Western Australia has improved more than that for females since 1973. No significant differences in mortality now exist between the sexes. Similar changes have been observed in the sex ratios for cerebral palsy. Some of these changes appear to be due to selective changes in the birthweight distribution of live male births. There has also been a selective improvement in male neonatal mortality in low birthweight infants.     

Sudden unexpected infant death in a French county.

We report a study of sudden unexpected infant death (SUID) in a French county (Seine-Maritime) between 1978 and 1981 (rate of 2.71 per 1000 live births). The results agree with those of previous studies concerning sex ratio, seasonal variation, and peak age of death. No relation between gestational age and age of death was found. A comparison with matched living control infants was performed for 136 of the 207 total deaths for whom computerised medical data were available. Significant differences were found between these two groups in gestational age, birthweight, admission to a paediatric ward at birth, and proportion of single mothers. In analysing birthweight and gestational age separately, the birthweights of SUID cases were significantly lower than those of controls, whatever the gestational age. The converse was not true, however: in classifying infants by birthweight, a significant difference between the gestation period of SUID victims and controls was found only for low birthweight infants (less than 2500 g). It is considered that it may be possible to identify infants at particular risk of SUID within the group of babies admitted to hospital at birth for major problems, and a study is currently underway among infants born in Seine-Maritime in 1982.     

Food allergy and atopic dermatitis in low birthweight infants during early childhood

The prevalence rates of food allergy and atopic dermatitis in low birthweight infants were evaluated. In Fukuoka City, Japan, between July 1994 and September 1997, sufficient information including birthweight, gestational age, sex, feeding method and a history of food allergy was obtained from questionnaires at the well-baby check-ups of 21766 infants (18 mo of age) and 4378 children (3 y of age). All the children were examined by pediatricians with regard to the existence of atopic dermatitis. The prevalence rate (8.1%) of food allergy in infants with low birthweight (<2,500 g) was significantly lower than that (11.2%) in infants with normal birthweight (> or = 2,500 g) at 18 mo of age (p = 0.0002). Atopic dermatitis was also observed at a lower prevalence rate (1.2%) in infants with low birthweight than in those with normal birthweight (2.3%) at the same age (p = 0.0041). However, this significance was lost at 3 y of age. Other characteristics including male sex and breast-feeding showed independent risks for the development of food allergy and atopic dermatitis at both ages. CONCLUSION: This study found that low birthweight was significantly associated with a lower risk of both food allergy and atopic dermatitis at 18 mo of age.     

Changing mortality and causes of death in infants 23–27 weeks'' gestational age

OBJECTIVE: To contrast the mortality rates and changes in the causes of death of very preterm infants (23-27 weeks), before and after the introduction of exogenous surfactant in 1991, and to identify any preventable causes of death remaining in the 1990s. METHODOLOGY: This was a cohort study on consecutive preterm infants of 23-27 weeks' gestational age born in the Royal Women's Hospital, Melbourne, a level III perinatal centre. The infants were livebirths free of lethal anomalies from two distinct eras, 1983-90, and 1992-96, inclusive. The main outcome measures were mortality during the primary hospitalization and the causes of death before and after the introduction of exogenous surfactant in 1991. RESULTS: In 1983-90, 261 of 508 livebirths (51.4%) of 23-27 weeks' gestational age died, a significantly higher proportion than the 109 of 384 (28.4%) livebirths who died in the period 1992-96. The mortality rate fell significantly with increasing gestational age and was lower at each week of gestational age in 1992-96. More infants who died in 1992-96 were treated intensively in the neonatal intensive care unit (NICU). Of the group of infants who died or who were treated intensively in NICU, respiratory causes of death predominated. However, the causes of death changed over time. In 1992-96 proportionally fewer infants died from respiratory causes (1983-90, 82.5%; 1992-96, 60.0%; odds ratio (OR) 0.31, 95%; confidence interval (CI) 0.16-0.57), but more from septic causes (1983-90, 14.3%; 1992-96, 43.8%; OR 4.9, 95%; CI 2.6-9.2). CONCLUSIONS: As the mortality rate has fallen over time, respiratory causes of death have diminished, but septic causes of death have increased. Further advances in the use of exogenous surfactant and respiratory support may reduce respiratory deaths. Effective strategies to reduce nosocomial infections are urgently required.     

Physician counselling practices and decision-making for extremely preterm infants in the Pacific Rim

OBJECTIVES: This study was undertaken to evaluate physician counselling practices and resuscitation decisions for extremely preterm infants in countries of the Pacific Rim. We sought to determine the degree to which physician beliefs, parents' opinion and medical resources influence decision-making for infants at the margin of viability. METHODS: A survey was administered to neonatologists and paediatricians who attend deliveries of preterm infants in Australia, Hong Kong, Japan, Malaysia, Taiwan and Singapore. Questions were asked regarding physician counselling practices, decision-making for extremely preterm infants and demographic information. RESULTS: Physicians counsel parents antenatally with increasing frequency as gestational age increases. Most physicians discuss infant mortality and morbidity with parents prior to delivery. Physicians less frequently discuss the option of no resuscitation of an extremely preterm infant, withdrawal of support at a later time, or financial costs to parents. Severe congenital malformations, perception of a poor future quality of life, parental wishes and a high probability of death for the infant are influential in limiting resuscitation in very preterm infants for a majority of physicians. Less influential factors are parent socioeconomic status, language barriers, financial costs for the family, allocation of national resources, moral or religious considerations, or fear of litigation. Physician thresholds for resuscitation of infants ranged between 22 and 25 weeks gestation and between 400 and 700 g birthweight. CONCLUSIONS: We report physician beliefs and practices regarding resuscitation and the counselling of parents of extremely preterm infants in Pacific Rim countries. While we find variation among countries, physician practices appear to be determined by ethical decision-making and medical factors rather than social or economic factors in each country.