Hospital admissions and length of stay for coronary disease in an Aboriginal cohort.

BACKGROUND AND AIMS: Coronary disease (CHD)-related hospital admission is more common among indigenous than non-indigenous Australians. We aimed to identify predictors of hospital admission potentially useful in planning prevention programs. METHODS AND RESULTS: Length of stay (LOS), interval between, and number of recurrent admissions were modelled with proportional hazards or negative binomial models using lifestyle data recorded in 1988-1989 among Aborigines (256 women, 258 men, aged 15-88years) linked to hospital records to 2002. Among 106 Aborigines with CHD, hypertension (hazard ratio (HR) 1.69, 95% CI 1.05-2.73); smoking (HR 1.90, 95% CI 1.02-3.53); consuming processed meat >4 times/month (HR 1.81, 95% CI 1.01-3.24); >6 eggs/week (HR 1.73, 95% CI 1.03-2.94); and lower intake of alcohol (HR 0.54, 95% CI 0.35-0.83) predicted LOS. Eating eggs (HR 1.05, 95% CI 1.01-1.09) and bush meats > or =7 times/month (HR 0.46, 95% CI 0.23-0.92) predicted interval between recurrent admissions. Hypertension (IRR 4.07; 95% CI 1.32-12.52), being an ex-drinker (IRR 6.60, 95% CI 2.30-19.00), eating red meat >6 times/week (IRR 0.98, 95% CI 0.97-0.99), bush meats >7 times/month (IRR 0.26, 95% CI 0.10-0.67), and adding salt to meals (IRR 3.16, 95% CI 1.12-8.92) predicted number of admissions. CONCLUSION: Hypertension, alcohol drinking, smoking, and diet influence hospital admissions for CHD in Aboriginal Australians.

The effect of transition from traditional to urban life-style on the insulin secretory response in Australian Aborigines.

Recent epidemiologic studies have revealed a high prevalence of maturity-onset diabetes in certain populations that have undergone comparatively rapid urbanization. There is evidence suggesting that Australian Aborigines may respond to urbanization in this way. Thirteen full-blood Aborigines from the Mowanjum Community, Derby, Western Australia, cooperated in the present study. They spent 3 mo living in their traditional hunter-gatherer life-style, after which their insulin response to glucose was measured in a starch tolerance test. The findings were compared in follow-up studies conducted 3 mo after returning to their urban environment. Similar studies were conducted in Caucasians of comparable age and weight. Fasting glucose concentrations were lower in Aborigines than in Caucasians and were unaffected by life-style changes. Although basal insulin levels were similar in the three groups, there were striking intergroup differences in the insulin responses to glucose. The areas under the insulin curves in the first hour after starch ingestion were: urban Aborigines 4478 +/- 465 microU/ml-1/min, traditional Aborigines 2959 +/- 301 microU/ml-1/min, and Caucasians 2097 +/- 224 microU/ml-1/min. This appeared to reflect differences in the early rates of change of glucose concentrations. The data suggest that these Aborigines have an abnormally high insulin response to glucose, which is ameliorated, but not normalized, by reverting to their traditional life-style.

Risk factors for diabetes and cardiovascular disease in young Australian aborigines. A 5-year follow-up study.

OBJECTIVE: To test the hypothesis that hyperinsulinemia and glucose intolerance are present at an early age in australian aborigines and can be used to predict the eventual development of NIDDM. RESEARCH DESIGN AND METHODS: Baseline anthropometric, pubertal stage, and blood pressure data were collected for 100 Australian aboriginal children and adolescents in 1989. Plasma concentrations of glucose, insulin, C-peptide, triglycerides, and LDL, HDL, and total cholesterol were measured before and during an oral glucose tolerance test. All measurements were repeated in 74 individuals from the original study population in 1994. Results were compared among hyperinsulinemic and normoinsulinemic subjects, and subjects with normal or abnormal glucose tolerance. RESULTS: The percentage of subjects who were overweight increased from 2.7% at baseline to 17.6% 5 years later. At a mean age of 18.5 years, 8.1% of the population had impaired glucose tolerance (IGT), 2.7% had diabetes, and 21.6% had elevated cholesterol concentrations in plasma. Dyslipidemia was particularly prevalent among male subjects in the population: 34.4% had elevated plasma cholesterol and 21.9% had elevated LDL cholesterol values. Of the eight subjects who had diabetes or IGT in 1994, four were classified as hyperinsulinemic in 1989 and four were not. CONCLUSIONS: The major finding of this study is the high prevalence of risk factors for NIDDM and cardiovascular disease in this population of aboriginal children and adolescents. Abnormalities of carbohydrate and lipid metabolism were well established by late in the second decade of life. Although many subjects had high insulin levels and there was evidence of insulin resistance in the population, hyperinsulinemia did not predict the development of abnormal glucose tolerance 5 years later.

Acetylation phenotype and genotype in aboriginal leprosy patients from the north-west region of Western Australia.

N-Acetyltransferases (NAT1, NAT2) play an important role in biotransformation of a number of drugs and carcinogens. A polymorphism in the metabolism of such compounds by NAT2 has been known for many years but it is only recently that the underlying molecular genetics has been elucidated. In the present study, we have correlated acetylation phenotype and genotype in a group of 49 Australian Aborigines (26 males and 23 females; mean age = 50.5 yr) from the Derby region of Western Australia. Phenotype was determined using caffeine and genotype by an allele-specific polymerase chain reaction. The percentages of slow and rapid phenotypes were 36.7 and 63.3%, respectively, while the distribution of alleles for the NAT2 gene was 41% for the wildtype and 2, 17 and 40% for the M1, M2 and M3 mutations, respectively. This is the highest proportion of M3 mutations reported for any ethnic population. The observed genotype proportions were not significantly different from those predicted by the Hardy-Weinberg Law (chi 2 = 1.07, p > 0.05). Phenotype was predictable from genotype in 100% of patients. At the time of study, 29 of the Aborigines were receiving acedapsone intramuscularly for control of leprosy. Plasma dapsone concentrations in these patients were similar for both slow (n = 11) and rapid (n = 18) acetylators, suggesting that phenotype is unlikely to influence treatment outcome. The data show that Aborigines have a similar phenotype distribution to that of some Asian populations, but that there are differences in the frequencies of the M1, M2 and M3 mutant alleles.(ABSTRACT TRUNCATED AT 250 WORDS)

Allele and genotype frequencies of polymorphic cytochromes P4502D6, 2C19 and 2E1 in aborigines from western Australia.

The polymorphisms of the important xenobiotic metabolizing enzymes CYP2D6, CYP2C19 and CYP2E1 have been studied extensively in a large number of populations and show significant heterogeneity in the frequency of different alleles/genotypes and in the prevalence of the extensive and poor metabolizer phenotypes. Understanding of inter-ethnic differences in genotypes is important in prediction of either beneficial or adverse effects from therapeutic agents and other xenobiotics. Since no data were available for Australian Aborigines, we investigated the frequencies of alleles and genotypes for CYP2D6, CYP2C19 and CYP2E1 in a population living in the far north of Western Australia. Because of its geographical isolation, this population can serve as a model to study the impact of evolutionary forces on the distribution of different alleles for xenobiotic metabolizing enzymes. Twelve CYP2D6 alleles were analysed. The wild-type allele *1 was the most frequent (85.81%) and the non-functional alleles (*4, * 5, * 16) had an overall frequency of less than 10%. Only one subject (0.4%) was a poor metabolizer for CYP2D6 because of the genotype *5/*5. For CYP2C19, the frequencies of the *1 (wild-type) and the non-functional (*2 and *3) alleles were 50.2%, 35.5% and 14.3%, respectively. The combined CYP2C19 genotypes (*2/*2, *2/*3 or *3/*3) correspond to a predicted frequency of 25.6% for the CYP2C19 poor metabolizer phenotype. For CYP2EI, only one subject had the rare c2 allele giving an overall allele frequency of 0.2%. For CYP2D6 and CYP2C19, allele frequencies and predicted phenotypes differed significantly from those for Caucasians but were similar to those for Orientals indicating a close relationship to East Asian populations. Differences between Aborigines and Orientals in allele frequencies for CYP2D6* 10 and CYP2E1 c2 may have arisen through natural selection, or genetic drift, respectively.

Lactose malabsorption in Australian Aboriginal children.

The purpose of this study was to determine the prevalence of lactose malabsorption in healthy full-blood Australian Aboriginal children. Sixty-three Aboriginal subjects and forty-six non-Aboriginal controls ranging in age from six to 14 years were tested using the breath hydrogen method. Seventy percent of the Aboriginal subjects were found to be lactose malabsorbers and 9% of the controls. The results provide strong evidence that the majority of full-blood Aboriginal children are lactose malabsorbers and that the characteristic is well-established by 6-7 years of age, in common with most other non-Western populations.

Plasma glucose and insulin responses to starchy foods in Australian aborigines: a population now at high risk of diabetes.

We compared plasma glucose and insulin responses to an Aboriginal bushfood and its western equivalent in healthy Aborigines and Caucasians. Bush potato (Ipomoea costata), an Aboriginal bushfood which is slowly digested in vitro, and potato (Solanum tuberosum), which has a high glycemic index, were studied. The areas under the glucose and insulin curves for Aborigines were 34% and 42% smaller, respectively, after bush potato than after potato (p less than 0.05). In Caucasians only the insulin response to bush potato was lower (by 19%) than that to potato (p less than 0.05). Compared with Caucasians, Aborigines produced 2.5 times greater glucose and insulin responses to potato (p less than 0.025). Their insulin responses to bush potato were also twice as large (p less than 0.05) although glucose responses were not significantly different. These findings add weight to the hypothesis that rapidly digested carbohydrate in western diets may be one of the factors in the lifestyle change which precipitates diabetes in indigenous populations.

Lactose malabsorption in Australian Aborigines.

The aim of this study was to determine the incidence of lactose malabsorption in healthy, adult Australian Aborigines. Malabsorption of lactose was measured in 45 full-blood Aboriginal subjects and 37 non-Aboriginal, multiracial controls using the breath hydrogen method. Eighty-four percent of the Aboriginal subjects were found to be lactose malabsorbers and 64% developed abdominal pain or diarrhea. In the control subjects, 20% were found to be lactose malabsorbers and all of these developed symptoms of diarrhea. The results provide strong evidence that Australian Aborigines, in common with most human adults, are lactase deficient.

PIP: The aim of this study was to determine the incidence of lactose malabsorption in healthy, adult Australian Aborigines. Malabsorption of lactose was measured in 45 full blooded Aboriginal subjects and 37 nonAboriginal multiracial controls using the breath hydrogen method. 84% of the Aboriginal subjects were found to be lactose malabsorbers and 64% developed abdominal pain or diarrhea. In the control subjects, 20% were found to be lactose malabsorbers and all of these developed symptoms of diarrhea. The results provide strong evidence that Australian Aborigines, in common with most human adults, are lactase deficient.

Serum and plasma zinc, copper and iron concentrations in Aboriginal communities of North Western Australia.

Two aboriginal communities situated in the tropical north-west of the Australian continent have been investigated in regard to trace metal status (zinc, copper, and iron) and other laboratory and epidemiological information. A total of 364 persons, ranging in age from 5 to 77 years were studied. The incidence of hypozincemia (serum or plasma zinc concentration less than 0.71 micrograms/ml) of the two communities when combined was 24.4%, while hypercupremia (defined as serum or plasma copper levels greater than 1.38 micrograms/ml) was 47.9%. Depressed serum iron levels were demonstrated in more than 50% of the Aborigines studied. Hypozincemia was most prevalent (incidence 31 to 67%) in children at the time of the important pre- and postadolescent growth period (10 to 15 years) and in women beyond 60 years of age (incidence 33 to 64%). Serum total protein and vitamin B12 levels tended to be increased. Mild anemia was seen in approximately one in five persons aged less than 20 years. Intestinal parasites and pathogenic enterobacteria were frequently isolated in fecal specimens. In one community, half of the persons examined had positive isolates of enteric pathogens. Intestinal parasites predominated and were more frequently isolated from persons aged less than 20 years. Ancylostoma duodenale accounted for 32% of the pathogens isolated. Evidence is presented that suggests that both communities are exposed to numerous bacterial, viral, and parasitic infections. The diet consumed in these communities is predominately white flour and refined sugar. Geophagia is practiced in this area of Australia. It is emphasied that all the etiological prerequisites and many of the laboratory findings ascribed to the zinc deficiency syndrome appear to be operating in the two Aboriginal communities studied.

Assessment of protein reserves (cellular mass) in Aboriginal children.

The body protein reserves, assessed indirectly by the measurement of intracellular water, was determined in free-living Aboriginal children and adolescents located in Central and Northwestern Australia. Fifty one individuals were studied--31 males and 20 females. Significant reductions were observed in intracellular water or cell mass relative to the cube of body length for Aboriginal females when compared to a control female group. Only marginal or borderline differences for the same parameters were observed when Aboriginal males were compared with controls. Comparison of Aboriginal females with Aboriginal males demonstrated significant reductions in cell mass (intracellular water) relative to body length cubed in the female. This finding in the Aboriginal female is of concern because many become pregnant in the early teenage years. Evidence was found during the course of this study that plasma zinc concentrations were frequently low. This led to a concomitant study on serum and plasma trace metals in two Aboriginal settlements (364 individuals) to be published in a subsequent paper.

Alcohol-related problems among Aboriginal drinkers in the Kimberley region of Western Australia.

The paper reports on the prevalence of alcohol-related problems among drinkers in a stratified random sample of the adult Aboriginal population of the Kimberley region of Western Australia. Subjects were 265 current drinkers who were identified in the total sample of 516 Kimberley Aboriginal men and women over the age of 15 years. Participants' reports were obtained on their frequency and quantity of alcohol consumption, and their lifetime experience of 16 alcohol-related problems. The majority of Aboriginal drinkers in the Kimberley consumed harmful amounts of alcohol, and there was a high prevalence of the 16 alcohol-related problems which showed a high degree of internal coherence, with the first principal component accounting for 45% of the total variance. The number of alcohol-related problems which respondents reported was strongly related to the quantity and frequency of self-reported alcohol consumption.

Failure of pyrantel in treatment of human hookworm infections (Ancylostoma duodenale) in the Kimberley region of north west Australia.

A survey of 108 individuals from a coastal Aboriginal community in north Western Australia revealed that two species of gastrointestinal protozoan parasites (Giardia duodenalis--39.8%, Entamoeba coli--40.7%) and five gastrointestinal helminths (Hymenolepis nana--54.6%, Hookworm [Ancylostoma duodenale]--30.6%, Enterobius vermicularis--6.5%, Trichuris trichiura--2.8%, Strongyloides stercoralis 1.9%) were present. A total of 29 individuals infected with hookworm were offered treatment with either pyrantel pamoate at a single dose rate of 10 mg/kg body weight or albendazole (single 400 mg dose). Seven days after treatment stool samples were examined. Pyrantel had no significant effect against hookworm. In contrast, albendazole cleared hookworm infections completely and reduced the prevalence of Giardia. The former result suggests that locally A. duodenale is resistant to pyrantel and despite its relatively low cost and wide availability, should not be considered a drug of choice at this dose rate in the treatment of hookworm infections (A. duodenale) in endemic regions.

Efficacy of albendazole against Giardia and hookworm in a remote Aboriginal community in the north of Western Australia.

The parasitological, clinical efficacy and tolerability of albendazole in the treatment for both giardiasis and hookworm infection in a remote Aboriginal population was investigated. Albendazole at a dose rate of 400 mg daily for 5 days was highly effective in reducing hookworm egg numbers and both Giardia antigen and cysts. The 36.6% prevalence of Giardia prior to treatment fell to 12% between days 6 and 9, 15% for days 10-17 and rose to 28% between days 18 and 30. Tolerability and clinical efficacy were excellent. The effect of albendazole on hookworm was longer lasting than that on Giardia, reducing percent infection from over 76-2% on days 6-9 and zero by day 18-30 despite conditions highly conducive to rapid re-infection. We conclude that albendazole is highly efficacious against both parasites when used as described but that long term community benefit may require additional education programmes to avoid re-infection with Giardia although treatment strategies would seem appropriate for hookworm.

Deaths in Broome, Western Australia, 1883 to 1994.

We examined all records of deaths held in the Derby Courthouse (1883 to 1895) and the Broome Courthouse (from 1896). Records of 3409 deaths (2659 males, 750 females) were analysed. Race of origin was ascertained from > 99 per cent of records: 35.9 per cent of deaths were of Aboriginals, 42.8 per cent of Asians and 21.3 per cent were among other races. In the early decades (1880s to 1920s) most deaths were of young Asian males and related to deep-sea diving in the pearling industry; many other deaths were caused by homicide and suicide. Pearling deaths declined after World War I and the number of Aboriginal deaths increased. The 80 to 100 deaths caused by the Japanese air raid in March 1942 were not entered into the Broome register. After World War II deaths among young males and Asians decreased and reported Aboriginal deaths increased; many were of malnourished infants and young children with infections. In the 1970s and 1980s deaths of young adults in motor vehicle accidents and of young adults from homicide and suicide increased; some occurred in custody. The pearling industry caused hundreds of deaths in the late nineteenth century and in the first two decades of this century, particularly among young Asian divers. Many were recorded in the Derby and Broome Death Registries but others were not recorded. These official records show changing patterns of mortality, for example, mortality associated with violence, infection and undernutrition (in young Aboriginal children), and more recently, motor vehicle accidents.

Alcohol intake and incidence of coronary disease in Australian aborigines.

AIMS: To examine risk for coronary heart disease (CHD) and cardiovascular disease (CVD) in relation to alcohol in a cohort of Australian Aborigines. METHODS: In 1988-1989, alcohol intake, drinking pattern, and beverage preference were elicited by interviewer-administered questionnaire in Western Australian Aborigines (258 men and 256 women) and cardiovascular outcomes ascertained through linkage to mortality and hospital admission records to 2002. RESULTS: In proportional hazards models, risk for CHD, relative to lifetime abstainers, was significantly increased in ex-drinkers [Hazard ratio (HR), 2.29; 95% confidence intervals (CI), 1.23-4.27], those drinking 41-60 g/day in men or 21-40 g/day in women (HR 2.80; 95% CI, 1.04-7.53) and those drinking >150 g/day for men or >100 g/day for women (HR, 2.25; 95% CI, 1.03-4.90) with a J-shaped relationship. Low-to-moderate drinkers had lower waist girth, exercised more and had a lower prevalence of overweight and smoking than at-risk drinkers. A preference for wine was associated with lower HR (0.28; 95% CI, 0.10-0.95). With CVD, only ex-drinkers showed significantly increased risk (HR, 1.87; 95% CI, 1.20-2.91). CONCLUSIONS: More favourable health-related behaviours in low-to-moderate drinkers suggest that lower risk could be mediated by lifestyle, as proposed in other populations.

Alcohol intake and incidence of coronary disease in Australian aborigines.

AIMS: To examine risk for coronary heart disease (CHD) and cardiovascular disease (CVD) in relation to alcohol in a cohort of Australian Aborigines. METHODS: In 1988-1989, alcohol intake, drinking pattern, and beverage preference were elicited by interviewer-administered questionnaire in Western Australian Aborigines (258 men, 256 women) and cardiovascular outcomes ascertained through linkage to mortality and hospital admission records to 2002. RESULTS: In proportional hazards models, risk for CHD, relative to lifetime abstainers, was significantly increased in ex-drinkers [Hazard ratio (HR) 2.29, 95% CL 1.23, 4.27], those drinking 41-60 g/day in men or 21-40 g/day in women (HR 2.80, 95% CL 1.04, 7.53), and those drinking >150 g/day for men or >100 g/day for women (HR 2.25, 95% CL 1.03, 4.90) with a J-shaped relationship. Low-to-moderate drinkers had lower waist girth, exercised more, and had a lower prevalence of overweight and smoking than at-risk drinkers. A preference for wine was associated with lower HR (0.28, 95% CL 0.10, 0.95). With CVD, only ex-drinkers showed significantly increased risk (HR 1.87, 95% CL 1.20, 2.91). CONCLUSIONS: More favourable health-related behaviours in low-to-moderate drinkers suggest that lower risk could be mediated by lifestyle, as proposed in other populations.

Health-related behaviours as predictors of mortality and morbidity in Australian Aborigines.

OBJECTIVE: To examine predictors of coronary heart disease (CHD) and all-cause mortality in Aboriginal Australians. METHOD: In 1988-89, a survey of Western Australian Aborigines (256 women, 258 men) aged 15-88 years documented diet, alcohol and smoking habits. Linkage to mortality and hospital admissions to the end of 2002 provided longitudinal data for modelling of coronary heart disease endpoints and all-cause mortality using Cox regression. RESULTS: Coronary heart disease risk increased with smoking (HR 2.62, 95% CI: 1.19, 5.75), consumption of processed meats >once/week (HR 2.21, 95% CI: 1.05, 4.63), eggs >twice/week (HR 2.59, 95% CI: 1.11, 6.04) and using spreads on bread (HR 3.14. 95% CI: 1.03, 9.61). All-cause mortality risk was lower with exercise >once/week (HR 0.51, 95% CI 0.26, 1.05), increased in ex-drinkers (HR 3.66, 95% CI: 1.08, 12.47), heavy drinkers (HR 5.26, 95% CI: 1.46, 7.52) and with consumption of take away foods >nine times/month (HR 1.78, 95% CI 0.96, 3.29). Greater alcohol intake, smoking and adverse dietary choices clustered in 53% of men and 56% of women and increased risk of coronary heart disease (HR 2.1, 95% CI: 1.1, 4.0) and all-cause mortality (HR 2.3, 95% CI: 1.2, 4.2). CONCLUSION: Lifestyle in Aboriginal Australians predicts coronary heart disease and all-cause mortality. Clustering of adverse behaviours is common and increases risk of coronary heart disease and death.

Population genetic studies in the Kimberley of Western Australia.

More than 800 blood samples from members of 13 tribal groups in the northwest of Australia have been tested for 18 enzyme systems controlled by 21 loci and for haemoglobin. Two novel alleles, PGM2(11) and ACP1F, are each restricted to a single tribal population, suggesting relatively recent mutations. Other alleles conform very broadly with their distributions in other Australian Aboriginal populations. In particular, PGM2(3) maintains its inland distribution whilst PGDE and PEP B6 continue to be restricted to the north of the continent. Comparisons between tribes show the Baada to be distinctive, with high values of PGM1(2), GPT2, CA2(4) and ESD2 as well as having the novel allele ACP1F.