Nutritional predictors of successful chronic disease prevention for a community cohort in Central Australia.

OBJECTIVE: To investigate biomarkers of nutrition associated with chronic disease absence for an Aboriginal cohort. DESIGN: Screening for nutritional biomarkers was completed at baseline (1995). Evidence of chronic disease (diabetes, CVD, chronic kidney disease or hypertension) was sought from primary health-care clinics, hospitals and death records over 10 years of follow-up. Principal components analysis was used to group baseline nutritional biomarkers and logistic regression modelling used to investigate associations between the principal components and chronic disease absence. SETTING: Three Central Australian Aboriginal communities. SUBJECTS: Aboriginal people (n 444, 286 of whom were without chronic disease at baseline) aged 15-82 years. RESULTS: Principal components analysis grouped twelve nutritional biomarkers into four components: 'lipids'; 'adiposity'; 'dietary quality'; and 'habitus with inverse quality diet'. For the 286 individuals free of chronic disease at baseline, lower adiposity, lower lipids and better dietary quality components were each associated with the absence at follow-up of most chronic diseases examined, with the exception of chronic kidney disease. Low 'adiposity' component was associated with absence of diabetes, hypertension and CVD at follow-up. Low 'lipid' component was associated with absence of hypertension and CVD, and high 'dietary quality' component was associated with absence of CVD at follow-up. CONCLUSIONS: Lowering or maintenance of the factors related to 'adiposity' and 'lipids' to healthy thresholds and increasing access to a healthy diet appear useful targets for chronic disease prevention for Aboriginal people in Central Australia.

Depression in Aboriginal men in central Australia: adaptation of the Patient Health Questionnaire 9.

BACKGROUND: While Indigenous Australians are believed to be at a high risk of psychological illness, few screening instruments have been designed to accurately measure this burden. Rather than simply transposing western labels of symptoms, this paper describes the process by which a screening tool for depression was specifically adapted for use across multiple Indigenous Australian communities. METHOD: Potential depression screening instruments were identified and interrogated according to a set of pre-defined criteria. A structured process was then developed which relied on the expertise of five focus groups comprising of members from primary Indigenous language groups in central Australia. First, focus group participants were asked to review and select a screening measure for adaptation. Bi-lingual experts then translated and back translated the language within the selected measure. Focus group participants re-visited the difficult items, explored their meaning and identified potential ways to achieve equivalence of meaning. RESULTS: All five focus groups independently selected the Primary Health Questionnaire 9, several key conceptual differences were exposed, largely related to the construction of hopelessness. Together with translated versions of each instrument for each of the five languages, a single, simplified English version for use across heterogeneous settings was negotiated. Importantly, the 'code' and specific conceptually equivalent words that could be used for other Indigenous language groups were also developed. CONCLUSIONS: The extensive process of adaptation used in this study has demonstrated that within the context of Indigenous Australian communities, across multiple language groups, where English is often a third or fourth language, conceptual and linguistic equivalence of psychological constructs can be negotiated. A validation study is now required to assess the adapted instrument's potential for measuring the burden of disease across all Indigenous Australian populations.

A pilot study of Aboriginal health promotion from an ecological perspective.

BACKGROUND: For health promotion to be effective in Aboriginal and Torres Strait Islander Communities, interventions (and their evaluation) need to work within a complex social environment and respect Indigenous knowledge, culture and social systems. At present, there is a lack of culturally appropriate evaluation methods available to practitioners that are capable of capturing this complexity. As an initial response to this problem, we used two non-invasive methods to evaluate a community-directed health promotion program, which aimed to improve nutrition and physical activity for members of the Aboriginal community of the Goulburn-Murray region of northern Victoria, Australia. The study addressed two main questions. First, for members of an Aboriginal sporting club, what changes were made to the nutrition environment in which they meet and how is this related to national guidelines for minimising the risk of chronic disease? Second, to what degree was the overall health promotion program aligned with an ecological model of health promotion that addresses physical, social and policy environments as well as individual knowledge and behaviour? METHODS: Rather than monitoring individual outcomes, evaluation methods reported on here assessed change in the nutrition environment (sports club food supply) as a facilitator of dietary change and the 'ecological' nature of the overall program (that is, its complexity with respect to numbers of targets, settings and strategies). RESULTS: There were favourable changes towards the provision of a food supply consistent with Australian guidelines at the sports club. The ecological analysis indicated that the design and implementation of the program were consistent with an ecological model of health promotion. CONCLUSIONS: The evaluation was useful for assessing the impact of the program on the nutrition environment and for understanding the ecological nature of program activities.

Physical Activity and Self-Reported Metabolic Syndrome Risk Factors in the Aboriginal Population in Perth, Australia, Measured Using an Adaptation of the Global Physical Activity Questionnaire (GPAQ).

Background: Complex, ongoing social factors have led to a context where metabolic syndrome (MetS) is disproportionately high in Aboriginal Australians. MetS is characterised by insulin resistance, abdominal obesity, hypertension, hypertriglyceridemia, high blood-sugar and low HDL-C. This descriptive study aimed to document physical activity levels, including domains and intensity and sedentary behaviour, and MetS risk factors in the Perth Aboriginal (predominately Noongar) community. Methods: The Global Physical Activity Questionnaire (GPAQ), together with a questionnaire on self-reported MetS risk factors, was circulated to community members for completion during 2014 (n = 129). Results: Data were analysed using chi-squared tests. The average (SD) age was 37.8 years (14) and BMI of 31.4 (8.2) kg/m2. Occupational, transport-related and leisure-time physical activity (PA) and sedentary intensities were reported across age categories. The median (interquartile range) daily sedentary time was 200 (78, 435), 240 (120, 420) and 180 (60, 300) minutes for the 18-25, 26-44 and 45+ year-olds, respectively (p = 0.973). Conclusions: An in-depth understanding of the types, frequencies and intensities of PA reported for the Perth Aboriginal community is important to implementing targeted strategies to reduce the prevalence of chronic disease in this context. Future efforts collaborating with community should aim to reduce the risk factors associated with MetS and improve quality of life.

C-reactive protein concentrations are very high and more stable over time than the traditional vascular risk factors total cholesterol and systolic blood pressure in an Australian aboriginal cohort.

BACKGROUND: Stability of circulating high-sensitivity C-reactive protein (hsCRP) concentrations has implications for its utility in assessing cardiovascular disease (CVD) risk. We sought to determine hsCRP reproducibility in an indigenous Australian cohort with a view to use hsCRP as a marker of future CVD in community-based risk-factor screenings. METHODS: Seventy people living in a community on the northern coast of Australia participated in 2 risk-factor screenings over a median (interquartile range) follow-up time of 829 (814-1001) days. hsCRP was measured by high-sensitivity nephelometry. RESULTS: Geometric mean hsCRP concentrations at baseline and follow-up were 4.5 and 5.1 mg/L, respectively (P = 0.220), and Pearson product-moment correlation was 0.775. The proportion of people at high CVD risk (hsCRP >3.0 mg/L) at baseline was 67.1% and remained consistently high (68.6%) at follow-up. Linear regression analysis for follow-up hsCRP as a function of baseline hsCRP, sex, and differences in total and regional body fatness showed that baseline hsCRP was the single predictor in the model, accounting for 63.9% of the total variance in follow-up hsCRP (P(model) < 0.001). Prevalence agreement (95% CI) between baseline and follow-up for the hsCRP >3.0 mg/L category was 84% (73%-92%) (P(McNemar) = not significant), and kappa coefficient was fair (0.64, compared with 0.31 for systolic blood pressure > or =140 mmHg and 0.43 for total cholesterol > or =5.5 mmol/L). CONCLUSIONS: hsCRP concentrations remained consistently reproducible over time across a wide concentration range in an Aboriginal cohort. Correlations between concentrations over time were better than for other traditional CVD risk factors. hsCRP concentration has potential as a marker of future CVD risk.

Increased coated-platelet levels in chronic haemodialysis patients.

AIM: To determine if levels of coated-platelets, which are potentially pro-thrombotic, are increased in end-stage renal disease patients on haemodialysis, a condition associated with high cardiovascular disease risk. METHODS: In a cross-sectional observational study, coated-platelet levels were measured by flow cytometry in 25 end-stage renal failure haemodialysis patients and 25 controls without renal disease. Associations between coated-platelet levels and clinical and biochemical factors relevant to renal and cardiovascular disease were evaluated. RESULTS: Mean +/- SD coated-platelet levels were higher in the dialysis group than in the control group (39.3+/-14.3% vs 30.9+/-10.3%, P=0.02). The number of subjects with high coated-platelet levels (>40%) was larger in the dialysis than in the control group (13/25 vs 4/25, chi(2) test, P=0.007). On univariate analysis, coated-platelet levels correlated with serum C-reactive protein levels in renal failure (r=0.47, P=0.02) and inversely with white cell count in the control group (r= -0.60, P=0.001). Coated-platelet levels were higher in dialysis patients reporting alcohol abstinence than among those reporting 'social' drinking (44.3+/-12.6 vs 28.8+/-13.5%, P=0.01). Age, gender, body weight, smoking, diabetes, lipid levels and lipid-lowering drugs were not associated with coated-platelet levels (all P>0.05). CONCLUSION: Coated-platelet levels are increased in haemodialysis patients relative to subjects with normal renal function, and are related to inflammation and alcohol abstinence. Other vascular risk factors, such as smoking, lipids and diabetes, were not related to coated-platelet levels. Coated-platelets may be implicated in the increased thrombosis and vascular risk in end-stage renal disease.

Setting and meeting priorities in Indigenous health research in Australia and its application in the Cooperative Research Centre for Aboriginal health.

Priority setting is about making decisions. Key issues faced during priority setting processes include identifying who makes these decisions, who sets the criteria, and who benefits. The paper reviews the literature and history around priority setting in research, particularly in Aboriginal health research. We explore these issues through a case study of the Cooperative Research Centre for Aboriginal Health (CRCAH)'s experience in setting and meeting priorities.Historically, researchers have made decisions about what research gets done. Pressures of growing competition for research funds and an increased public interest in research have led to demands that appropriate consultation with stakeholders is conducted and that research is of benefit to the wider society. Within Australian Aboriginal communities, these demands extend to Aboriginal control of research to ensure that Aboriginal priorities are met.In response to these demands, research priorities are usually agreed in consultation with stakeholders at an institutional level and researchers are asked to develop relevant proposals at a project level. The CRCAH's experience in funding rounds was that scientific merit was given more weight than stakeholders' priorities and did not necessarily result in research that met these priorities. After reviewing these processes in 2004, the CRCAH identified a new facilitated development approach. In this revised approach, the setting of institutional priorities is integrated with the development of projects in a way that ensures the research reflects stakeholder priorities.This process puts emphasis on identifying projects that reflect priorities prior to developing the quality of the research, rather than assessing the relevance to priorities and quality concurrently. Part of the CRCAH approach is the employment of Program Managers who ensure that stakeholder priorities are met in the development of research projects. This has enabled researchers and stakeholders to come together to collaboratively develop priority-driven research. Involvement by both groups in project development has been found to be essential in making decisions that will lead to robust and useful research.

Longitudinal analysis of low-molecular weight fluorophores in type 1 diabetes mellitus.

OBJECTIVES: Circulating low molecular weight (<10 kDa) fluorophores (LMW-F) measured by non-specific fluorescence spectroscopy may detect small advanced glycation end-products (AGEs) not recognized by other assays. This longitudinal study assessed correlates of LMW-F and predictive power of LMW-F levels for vascular health in Type 1 diabetes (T1DM) patients. METHODS: Fasting patients with T1DM (n=37) were studied twice at intervals of 12-60 months (mean+/-SD, 33+/-15 months). LMW-F levels were also measured once in 112 healthy control subjects. RESULTS: Relative to controls, LMW-F levels were higher in diabetic subjects at initial and final time points (mean+/-SD), 5.4+/-1.9 AU/ml and 4.5+/-1.8 AU/ml respectively vs. 3.8+/-2.1 AU/ml; p=0.0001 and p=0.06). Baseline LMW-F levels predicted subsequent hs-CRP and oxLDL/LDL values. LMW-F levels decreased significantly over time in diabetes (5.4+/-1.9 vs. 4.5+/-1.8 AU/ml; p=0.02). Rises in LMW-F levels in individual diabetic subjects correlated significantly with worsening renal function (BUN), glycemia (HbA1c) and with vascular dysfunction (systemic vascular resistance). CONCLUSIONS: LMW-F levels predict levels of inflammation and oxidation in T1DM. Changes in LMW-F levels in T1DM reflect variations in glycemia and renal function. Biochemical characterization of LMW-F would facilitate understanding of the potential utility of LMW-F as a therapeutic target.

Agreement between laboratory results and on-site pathology testing using Bayer DCA2000+ and Cholestech LDX point-of-care methods in remote Australian Aboriginal communities.

BACKGROUND: Indigenous Australians experience high risk of diabetes and cardiovascular disease. On-site pathology data can help identify those at risk. We sought to evaluate point-of-care (POC) analysers in remote Australian communities. METHODS: Results obtained from population screening (n=76-118) on the DCA2000+ and Cholestech LDX analysers were compared to laboratory measures. Results were compared using parametric and non-parametric statistical analyses, including the use of conventional cut-off values for pathology markers. RESULTS: Agreements (95% CI) between the two methods for categorising results according to the selected cut-off values ranged from 88% (77-94%) for HDL-C to 99% (92-100%) for glucose, and Kappa coefficients ranged from 0.668 for total cholesterol to 0.945 for glucose. Differences in median values were not clinically meaningful but were statistically significant (P<0.05) for urinary albumin (18.8 [inter-quartile range: 7.5-41.7] vs. 18.0 [5.5-43.2] mg/L), creatinine (12.1 [7.9-17.1] vs. 12.4 [8.1-17.0] mmol/L) and albumin:creatinine ratio (ACR; 1.66 [0.70-3.53] vs. 1.27 [0.46-3.03] mg/mmol), HDL cholesterol (HDL-C; 1.05 [0.95-1.25] vs. 1.00 [0.81-1.20] mmol/L), triglycerides (1.65 [1.12-2.19] vs. 1.49 [1.07-2.36] mmol/L) and glucose (5.2 [4.5-6.0] vs. 5.2 [4.7-5.8] mmol/L), respectively, for POC and laboratory methods. Median HbA1c (5.6% [5.3-6.0%] vs. 5.5% [5.3-6.1%]) and total cholesterol (4.4 [3.8-5.0] vs. 4.4 [3.8-5.1] mmol/L) did not differ significantly. Bland-Altman analyses showed statistically significant (but not clinically meaningful) variation in the measurement difference across analyte concentration for all measures except ACR and total cholesterol. CONCLUSION: POC instruments provided a reliable alternative to conventional laboratory methods for screening for chronic disease risk factors in locations remote from urban centres.

Leanness and type 2 diabetes in a population of indigenous Australians.

OBJECTIVE: To determine the prevalence of type 2 diabetes and its risk factors in a population of indigenous Australians. RESEARCH DESIGN AND METHODS: A cross-sectional study of 332 indigenous community residents aged 15 years and over with fasting blood samples and anthropometric measurements. RESULTS: Almost half of the study population (47.3%) was extremely lean (BMI<22 kg/m(2)). Leanness was particularly pronounced in the youngest age group (15<20 years), 78% of which had a BMI<22 kg/m(2). The prevalence of diabetes was 12%. It was highest in those 45-54 years and declined in older aged people. No cases of diabetes were detected in those aged less than 30 years. Diabetes prevalence was strongly linked to BMI and age (age-adjusted odds ratio=24.1, 95% CI 6.0-96.5, p<0.001) for BMI>or=25 kg/m(2) versus BMI<22 kg/m(2). Those with the lowest diabetes risk profile are lean (BMI<22 kg/m(2)) and/or young (age 15-34 years). CONCLUSIONS: These results highlight that strategies to prevent or delay the onset of diabetes should focus on the maintenance of leanness from adolescence and throughout adult life whilst young people are still in the process of forming lifelong habits.

Test agreement for classifying diabetes in indigenous Australians.

OBJECTIVE: To evaluate for Indigenous Australians the agreement between a fasting plasma glucose (FPG) criterion of 7.0 mmol/L and diabetes test results using a two-hour oral glucose tolerance test (OGTT), comparing relationships between test agreement and prevalence to similar studies. METHODS: Screening was undertaken in 25 remote settlements. Agreement between FPG and OGTT results was evaluated using the kappa coefficient (chance-corrected agreement). RESULTS: Participants (n=3,249) ranged from 15-94 years. Kappa ranged from 0.70-0.77 for diabetes prevalence of 5-30%, with overall agreement of 0.76. In comparison studies, the relationship between kappa and diabetes prevalence was similar, but with kappa 0.21-0.48. CONCLUSIONS AND IMPLICATIONS: A FPG test with a 7.0 mmol/L cut-off is a reliable screening method, relative to the OGTT, for remote Indigenous settlements. The level of agreement between the FPG test and the OGTT for the Indigenous population surveyed is superior by far to agreement reported for non-Indigenous samples.

Contamination in HPLC quantified benzaldehyde is from polypropylene microtubes.

Semicarbazide-sensitive amine oxidase (SSAO; EC 1.4.3.6) is a copper-containing enzyme predominantly expressed by vascular smooth muscle cells. SSAO deaminates primary amines to produce aldehydes and oxygen peroxides, and may thus play a role in vascular damage. SSAO activity can be quantified by assaying benzaldehyde production using fluorescent derivatisation and separation by HPLC. We performed the derivatisation step in polypropylene or borosilicate glass tubes over 45 min at 95 degrees C. High and obstructing background levels of benzaldehyde were found in one batch of polypropylene vials, as opposed to its alternatives. Treatment and handling of product shipment into the country did not account for introduction of contaminant into packaged vials nor did any reagent used in the assay. We conclude that the source of contamination was most likely due to variation in the commercial production process. Use of borosilicate vials for assays based on aldehyde production and derivatisation is recommended.

A cross-sectional study of the effects of type 2 diabetes and other cardiovascular risk factors on structure and function of nonstenotic arteries of the lower limb.

OBJECTIVE: To compare intimal-medial thickness (IMT) and pulse wave conduction velocity (PWCV) in unstenosed arteries of the lower limb in subjects with and without type 2 diabetes and to determine the contribution of a range of cardiovascular risk factors. RESEARCH DESIGN AND METHODS: IMT and PWCV were determined in lower-limb arteries of 79 subjects with diabetes and 77 euglycemic subjects. Plasma lipids were determined by enzymatic assays, and LDL particle size was measured by gradient gel electrophoresis. Lag time for copper-induced oxidation of LDL was determined. alpha-Tocopherol, retinol, and ascorbate levels were determined by high-performance liquid chromatography, soluble E-selectin by enzyme-linked immunosorbent assay, and fibrinogen and factor VII by automated assays. RESULTS: Subjects with diabetes had greater superficial femoral artery (SFA) IMT, popliteal artery (PA) IMT, and SFA PWCV (all P < 0.0001). In univariate analysis, IMT and PWCV correlated with increased waist-to-hip ratio, triglycerides, and fibrinogen and inversely with HDL cholesterol and LDL size. Ascorbate was inversely associated with IMT, and LDL lag time was inversely correlated with PWCV. Subjects with the greatest number of features of the metabolic syndrome had the highest IMT and PWCV. CONCLUSIONS: Adverse changes in the structure and function of unstenosed lower-limb arteries are present in type 2 diabetes and are associated with features of the metabolic syndrome.

Fasting criteria for screening: test properties and agreement with glucose tolerance.

The objective of this study was to characterise test properties and agreement for fasting glucose cut-offs used for screening diabetes in Indigenous Australian communities, across a range of diabetes prevalence. The oral glucose tolerance test (OGTT) was administered to adult volunteers (n=3249) for community-based diabetes screening in isolated settlements (n=25). Two-hour post-load glucose concentration was the 'gold standard' against which test properties were characterised for fasting plasma glucose cut-offs at concentrations of > or = 7.0 mmol/l (ADA criterion) and > or = 7.8 mmol/l (WHO criterion). Test sensitivity (95% CI) was greater for the ADA (72.5%, 67.4-77.1%) versus the WHO criterion (61.5%, 56.1-66.6%). Specificity was high (>98%) using either criterion. The post-test likelihood of diabetes, given a population prevalence of 14.8%, was 89.1% using the ADA criterion, and 94.9% using the WHO criterion. The ADA criterion gave better agreement than did the WHO criterion for diabetes prevalence > or = 8.6%, and the probability of false results was lower using the ADA criterion, when diabetes prevalence was > or = 12.8%. According to the ADA criterion most individuals ascribed false negative results were aged > or = 35 years, overweight/obese, or had impaired fasting glucose. The fasting glucose criterion of 7.0 mmol/l was superior to 7.8 mmol/l in screening for diabetes.

Macrovascular disease risk factors and insulin resistance in Aboriginal and Torres Strait Islander people.

It has been proposed that insulin resistance (IR) underlies a cluster of cardiovascular disease (CVD) risk factors constituting a "metabolic syndrome." CVD is a leading cause of premature mortality among indigenous Australians. In a group of younger (15-44 years, fasting glucose <7.8 mmol/l) Aboriginal (n=643) and Torres Strait Islander (n=220) people participating in community-based risk factor surveys, we identified high prevalences of metabolic syndrome components: glucose intolerance, dyslipidaemia, hypertension, and IR. There were inconsistent associations of IR with other risk factors, and the data do not support a direct causal relationship between insulin and other metabolic variables. Rather, metabolic syndrome components may arise from social and environmental factors interacting with behavioural and biochemical factors in individuals.

Paraoxonase and other coronary risk factors in a community-based cohort.

Oxidative damage to circulating lipids and vascular tissues contributes to the initiation and progression of atherosclerosis. High density lipoprotein provides protection from atherosclerosis and the enzyme paraoxonase may contribute to this effect. The aim of the present study was to examine the trends in paraoxonase activity during the course of a community-directed life-style intervention, and relationships of paraoxonase activity to other coronary heart disease risk factors, in a cohort of Australian Aboriginal people.

Carotenoids: separation methods applicable to biological samples.

Epidemiologic and clinical studies have shown that a high intake of vegetables and fruit, with consequently high intakes and circulating concentrations of carotenoids, is associated with reduced risk of cardiovascular and other chronic diseases. The antioxidant properties of carotenoids are thought to contribute to these effects. The analysis of carotenoids in plasma, foods and tissues has thus become of interest in studies examining the role of diet in chronic disease prevention and management. High-performance liquid chromatography with ultra-violet or photodiode array detection is most often employed in routine use. We review these and other current methods for carotenoid analysis and information on sample stability relevant to epidemiological studies. The carotenoids remain an important and intriguing subject of study, with relevance to prevention of several important "lifestyle-related" diseases. Research into their physiological functions and their use as dietary markers requires sensitive, accurate and precise measurement. Further advances in these methodological areas will contribute to basic, clinical and public health research into the significance of carotenoid compounds in disease prevention.

Obesity, diabetes and associated cardiovascular risk factors among Torres Strait Islander people.

OBJECTIVE: To describe the lifestyle-related chronic disease and risk factor prevalence among Torres Strait Islander people of the Torres Strait and Northern Peninsula Area Health Service District and to compare this information with that available for the general Australian population. METHODS: Voluntary community-based screening for persons aged 15 years and older, including oral glucose tolerance test, anthropometry, health questionnaire, measurement of lipids and lipoprotein levels, blood pressure and urinary albumin to creatinine ratio. RESULTS: Nine communities participated in screening between 1993 and 1997. Five hundred and ninety-two participants (286 male and 306 female) identified as Torres Strait Islander. There were high prevalences of overweight (30%), obesity (51%), abdominal obesity (70%), diabetes (26%), hypercholesterolaemia (33%), albuminuria (28%), hypertension (32%) and tobacco smoking (45%). Only 8.5% of men and 6.5% of women were free of any cardiovascular risk factors (abdominal obesity, hypercholesterolaemia, hypertension, dyslipidaemia, smoking, diabetes, albuminuria). Comparisons of this information for Torres Strait Islander people with results from the AusDiab survey show rates of obesity three times higher and diabetes six times higher than for other Australians. CONCLUSIONS: There is a very high prevalence of preventable chronic disease and associated risk factors among Torres Strait Islander people of the Torres Strait and Northern Peninsula Area. IMPLICATIONS: Effective interventions to prevent and manage obesity, diabetes and associated cardiovascular risk factors are essential if the health of the Torres Strait Islander people is to improve. Such interventions could inform initiatives to stem the burgeoning epidemic of obesity and diabetes among all Australians.