Dietary sodium and iodine in remote Indigenous Australian communities: will salt-reduction strategies increase risk of iodine deficiency? A cross-sectional analysis and simulation study

Background

Excess salt intake is a global issue. Effective salt-reduction strategies are needed, however, as salt is a vehicle for iodine fortification, these strategies may also reduce iodine intake. This study examines the case of the remote Indigenous Australian population; we employed an innovative, objective method to assess sodium and iodine intakes against requirements and modelled the potential effects of salt-reduction strategies on estimated sodium and iodine intakes.

Design

Store-sales data were collected from 20 remote Indigenous community stores in 2012–14 representing the main source of food for 2 years for ~8300 individuals. Estimated average sodium and iodine intakes were compared against recommendations (nutrient reference values weighted to age and gender distribution). Linear programming was employed to simulate potential effects of salt-reduction strategies on estimated sodium and iodine intakes.

Results

Estimated average sodium intake was 2770 (range within communities 2410–3450) mg/day, far exceeding the population-weighted upper limit (2060 mg/day). Discretionary (added) salt, bread and processed meat were the biggest contributors providing 46 % of all sodium. Estimated average iodine intake was within recommendations at 206 (186–246) μg/day. The following scenarios enabled modelling of estimated average salt intake to within recommendations: 1) 67 % reduction in sodium content of bread and discretionary salt intake, 2) 38 % reduction in sodium content of all processed foods, 3) 30 % reduction in sodium content of all processed foods and discretionary salt intake. In all scenarios, simulated average iodine intakes remained within recommendations.

Conclusions

Salt intakes of the remote Indigenous Australian population are far above recommendations, likely contributing to the high prevalence of hypertension and cardiovascular mortality experienced by this population. Salt-reduction strategies could considerably reduce salt intake in this population without increasing risk of iodine deficiency at the population-level. These data add to the global evidence informing salt-reduction strategies and the evidence that these strategies can be synergistically implemented with iodine deficiency elimination programmes.

Trial registration

Australian New Zealand Clinical Trials Registry: ACTRN12613000694718.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2686-1) contains supplementary material, which is available to authorized users.

Associations of serum adiponectin with markers of cardio-metabolic disease risk in Indigenous Australian adults with good health, diabetes and chronic kidney disease

The higher serum adiponectin concentrations observed in females are often attributed to differences in adiposity or sex hormones. There is little data describing adiponectin in Indigenous Australians, and no studies examining its association with cardio-metabolic disease risk markers and chronic kidney disease (CKD).

AIM

To describe the relationship of serum adiponectin with cardio-metabolic disease risk markers and kidney function in a community-based sample of Indigenous Australian adults, with particular reference to sex-specific differences.

METHODS

A cross-sectional analysis of a community-based volunteer sample of 548 Indigenous Australian adults (62% female), stratified into five cardio-metabolic risk groups ranging from good health (strata-1) to high cardio-metabolic risk and low measured glomerular filtration rate (mGFR, <60ml/min/1.73m²) (strata-5). We examined serum adiponectin concentrations with cardio-metabolic risk markers, albuminuria and mGFR.

RESULTS

Indigenous Australian females had a lower than expected adiponectin concentration (3.5μg/ml), which was higher than males in strata 1-4 (as in other populations), but not in strata-5 (mGFR<60, p=0.19), and higher leptin: adiponectin ratio than other populations (7.8ng/μg - strata-1, healthy females; 12.2ng/μg - strata-3, females with diabetes and mGFR≥90). Female-gender, HDL-cholesterol (positive), mGFR and waist: hip ratio (WHR) (inverse) were independently associated with log-adiponectin when mGFR≥60; when mGFR<60, female-gender was associated with 0.27 units lower log-adiponectin.

CONCLUSION

Female-gender was not associated with higher adiponectin concentrations in Indigenous Australians with mGFR<60ml/min/1.73m². High WHR was frequent in both genders, and inversely associated with adiponectin. Longitudinal studies are needed to examine relationships of serum adiponectin, obesity and cardiovascular disease events in Indigenous Australians.

Polyunsaturated fatty acid intake and risk of cardiovascular mortality in a low fish-consuming population: a prospective cohort analysis

PURPOSE

The aim of this study was to examine the relationship between polyunsaturated fatty acids (PUFA) intake (n-6 and n-3) and mortality in a population-based sample with a low fish intake.

METHODS

Cox regression was used to examine the relationships between dietary PUFA intake and all-cause or CVD mortality in the Australian Diabetes, Obesity and Lifestyle Study (AusDiab) cohort, a population of 11,247 Australians aged ≥25 years recruited in 1999/2000 and followed until 2012. Demographic, lifestyle and behavioural information were collected by questionnaire and fasting blood tests undertaken. Dietary intake was collected by a 121-item food frequency questionnaire. Vital status and causes of death were collected by death registry linkage.

RESULTS

Those in the highest quintile of n-6 PUFA intake had lower risk of CVD mortality (HR 0.57, 95 % CI 0.38-0.86) after age and sex adjustment, but this failed to retain significance after further risk factor adjustment. Consumption of ≥1 serves/week of non-fried fish was associated with reduced risk of CVD mortality (HR 0.64, 95 % CI 0.45-0.91, p = 0.013) compared to those eating less than 1 serve/month, after sex and age adjustment, but did not retain significance after further adjustment. However, long-chain n-3 intake was not associated with CVD mortality, and those in the highest quintile of n-3 intake had a higher risk of all-cause mortality.

CONCLUSIONS

These findings do not support previous suggestions that n-6 PUFA have adverse effects on CVD risk. Greater intake of non-fried fish was associated with lower risk of CVD mortality, but those with the highest total n-3 intake were at slightly increased risk of all-cause mortality.

Remote school gardens: exploring a cost-effective and novel way to engage Australian Indigenous students in nutrition and health

OBJECTIVE

This pilot study aimed to determine the feasibility of a novel, low-cost program to get remote schools started in gardening and nutrition activities, for a lower cost than existing models, and without on-the-ground horticultural support.

METHODS

A multi-site, mixed methods case study was undertaken, in which four remote schools were shipped gardening materials and a nutrition and cooking resource, and provided with horticultural support by phone and email. A support register and teacher surveys were used for four months of evaluation.

RESULTS

The study demonstrated that the program is feasible, and may be associated with an increase from baseline in student's time spent cooking, gardening and on related classroom activities.

CONCLUSIONS

The program was delivered economically without the need for on-the-ground staff, in a manner that was acceptable to teachers.

IMPLICATIONS

This model may have application in remote schools throughout Australia, where there is a need to alter health impacting behaviours in high-risk populations. Lengthier program evaluation times and further resource development may be worth investigating in the future.

High folate levels in Aboriginal children after subsidised fruit and vegetables and mandatory folic acid fortification

OBJECTIVE

To evaluate the impact of a fruit and vegetable (F&V) subsidy program for disadvantaged Aboriginal children in Australia, implemented alongside the introduction of mandatory folic acid fortification of bread-making flour.

METHODS

A before-and-after evaluation was undertaken of a F&V subsidy program at three Aboriginal community-controlled health services in New South Wales. The program provided a weekly box of subsidised F&V linked to preventive health services and nutrition promotion for families. In this analysis, red blood cell (RBC) folate was assessed together with self-reported dietary intake at baseline and 12 months later in a cohort of 125 children (aged 0-17 years).

RESULTS

No children had low RBC folate at baseline or at follow-up; however, 33 children (26%) exceeded the reference range of RBC folate at baseline and 38 children (30%) exceeded the reference range at follow-up. Mean RBC folate levels increased substantially in children at follow-up (mean RBC folate z-score increased +0.55 (95%CI 0.36-0.74). Change in F&V intake (p=0.196) and mean bread intake (p=0.676) were not statistically significant predictors for change in RBC folate levels.

CONCLUSIONS

RBC folate levels increased among these disadvantaged Aboriginal children following mandatory folic acid fortification and participation in a subsidised F&V program. Even before mandatory folic acid fortification, none of these children had low RBC folate.

IMPLICATIONS

The effect on health of mandatory fortification of foods with folate is not clear, hence, ongoing population-based monitoring of folate levels to assess the impact of mandatory folic acid fortification is important.

Hyperfiltration in Indigenous Australians with and without diabetes

BACKGROUND

Hyperfiltration (HF) has been linked to the development of diabetic kidney disease (DKD), but the causative or predictive role of HF in the pathogenesis of DKD still remains unclear. To date, there have been no studies of HF in Indigenous Australians, a population with high rates of both diabetes and end-stage kidney disease. We aimed to compare the characteristics and frequency of HF in Indigenous Australians with and without type 2 diabetes.

METHODS

Indigenous Australian participants, recruited across five pre-defined strata of health, diabetes status and kidney function, had a reference glomerular filtration rate (GFR) measured using plasma disappearance of iohexol [measured GFR(mGFR)] over 4 h. HF was defined in various ways: (i) mGFR > 144 mL/min/1.73 m(2), which is mGFR > 1.96 × SD above the mean of the mGFR in non-diabetic participants with normal albuminuria and normal renal function (mGFR > 90 mL/min/1.73 m(2)); (ii) age-corrected mGFR (>144 mL/min/1.73 m(2)) to account for the effect of ageing on GFR in subjects over 40 years of age with cut-off 1 mL/min/1.73 m(2) lower for every year; (iii) mGFR > 144 mL/min, without correction for body surface area or age, as well as (iv) mGFR > 125 mL/min/1.73 m(2), without adjustment for age.

RESULTS

A total of 383 Indigenous participants, 125 with and 258 without diabetes, with mGFR > 90 mL/min/1.73 m(2) were studied. The proportion of participants with HF was 7% using mGFR > 144 mL/min/1.73 m(2), 11% using the age-adjusted definition, 19% using mGFR > 144 mL/min and 27% using mGFR > 125 mL/min/1.73 m(2). Diabetes was more common in participants with HF (40-74%) compared with normofiltering participants (28-31%), regardless of the definition of HF.

CONCLUSIONS

HF exists in Indigenous Australians with and without diabetes. A greater proportion of participants had diabetes in HF group compared with normofiltration group. Long-term follow-up of this cohort is necessary to determine if HF plays a role in the development of DKD and non-DKD.

Psychological distress and self-rated oral health among a convenience sample of Indigenous Australians

OBJECTIVES

This study sought to: a) estimate the frequency of poor self-rated oral health as assessed by a summary measure; b) compare frequency according to sociodemographic, behavioral, and psychological distress factors; and (3) determine if psychological distress was associated with poor self-rated oral health after adjusting for confounding.

METHODS

Data were from a convenience sample of Indigenous Australian adults (n = 289) residing in Australia's Northern Territory. Poor self-rated oral health was defined as reported experience of toothache, poor dental appearance or food avoidance in the last 12 months. A logistic regression model was used to evaluate socio-demographic, behavioral, and psychological distress associations with poor self-rated oral health (SROH). Effects were quantified as odds ratios (OR).

RESULTS

The frequency of poor SROH was 73.7 percent. High psychological distress, measured by a Kessler-6 score ≥8, was experienced by 33.9 percent of participants. Poor SROH was associated with high levels of psychological distress, being older, being female, and usually visiting a dentist because of a problem. In the multivariable model, factors that were significantly associated with poor SROH after adjustment for other covariates included having a high level of psychological distress (OR 2.74, 95% CI 1.25-6.00), being female (OR 2.22, 95% CI 1.03-4.78), and usually visiting a dentist because of a problem (OR 3.57, 95% CI 1.89-6.76).

CONCLUSIONS

Poor self-rated oral health and high levels of psychological distress were both highly frequent among this vulnerable population. Psychological distress was significantly associated with poor self-rated oral health after adjustment for confounding.

Performance of formulas for estimating glomerular filtration rate in Indigenous Australians with and without Type 2 diabetes: the eGFR Study

AIMS

It has been proposed that the Chronic Kidney Disease Epidemiology Collaboration formula estimates glomerular filtration rate more accurately than the Modification of Diet in Renal Disease formula. With the very high incidence of diabetes and end-stage kidney disease in Indigenous Australians, accurate estimation of glomerular filtration rate is vital in early detection of kidney disease. We aimed to assess the performance of the Chronic Kidney Disease Epidemiology Collaboration, Modification of Diet in Renal Disease and Cockcroft-Gault formulas in Indigenous Australians with and without diabetes.

METHODS

Indigenous Australians with (n = 224) or without (n = 340) Type 2 diabetes had a reference glomerular filtration rate measure using plasma disappearance of iohexol (measured glomerular filtration rate) over 4 h. Serum creatinine was measured by an enzymatic method. Performance was assessed by bias (measured glomerular filtration rate - estimated glomerular filtration rate) and accuracy (percentage of estimated glomerular filtration rate within 30% of measured glomerular filtration rate).

RESULTS

The median measured glomerular filtration rate (interquartile range) in participants with or without diabetes was 97 (68-119) and 108 (90-122) ml min(-1)  1.73 m(-2) , respectively. The Chronic Kidney Disease Epidemiology Collaboration formula had smaller bias and greater accuracy than the Modification of Diet in Renal Disease and Cockcroft-Gault formulas overall, for participants both with and without diabetes. However, for estimated glomerular filtration rate > 90 ml min(-1)  1.73 m(-2) , the Chronic Kidney Disease Epidemiology Collaboration formula had greater bias in participants with diabetes, underestimating measured glomerular filtration rate by 7.4 vs. 1.0 ml min(-1)  1.73 m(-2) in those without diabetes. The Chronic Kidney Disease Epidemiology Collaboration formula was less accurate across the whole range of estimated glomerular filtration rates in participants with vs. those without diabetes (87.1% vs. 93.3%).

CONCLUSIONS

The Chronic Kidney Disease Epidemiology Collaboration formula outperforms the Modification of Diet in Renal Disease and Cockcroft-Gault formulas overall in Indigenous Australians with and without diabetes. However, the Chronic Kidney Disease Epidemiology Collaboration formula has greater bias in people with diabetes compared with those without diabetes, especially in those with normal renal function.

Effect of periodontal therapy on arterial structure and function among aboriginal australians: a randomized, controlled trial

Observational studies and nonrandomized trials support an association between periodontal disease and atherosclerotic vascular disease. Both diseases occur frequently in Aboriginal Australians. We hypothesized that nonsurgical periodontal therapy would improve measures of arterial function and structure that are subclinical indicators of atherosclerotic vascular disease. This parallel-group, randomized, open label clinical trial enrolled 273 Aboriginal Australians aged ≥18 years with periodontitis. Intervention participants received full-mouth periodontal scaling during a single visit, whereas controls received no treatment. Prespecified primary end points measured 12-month change in carotid intima-media thickness, an indicator of arterial structure, and 3- and 12-month change in pulse wave velocity, an indicator of arterial function. ANCOVA used complete case data to evaluate treatment group differences. End points could be calculated for 169 participants with follow-up data at 3 months and 168 participants at 12 months. Intima-media thickness decreased significantly after 12 months in the intervention group (mean reduction=-0.023 [95% confidence interval {CI}, -0.038 to -0.008] mm) but not in the control group (mean increase=0.002 [95% CI, -0.017 to 0.022] mm). The difference in intima-media thickness change between treatment groups was statistically significant (-0.026 [95% CI, -0.048 to -0.003] mm; P=0.03). In contrast, there were no significant differences between treatment groups in pulse wave velocity at 3 months (mean difference, 0.06 [95% CI, -0.17 to 0.29] m/s; P=0.594) or 12 months (mean difference, 0.21 [95% CI, -0.01 to 0.43] m/s; P=0.062). Periodontal therapy reduced subclinical arterial thickness but not function in Aboriginal Australians with periodontal disease, suggesting periodontal disease and atherosclerosis are significantly associated.

Evidence for low high-density lipoprotein cholesterol levels in Australian indigenous peoples: a systematic review

Background

Low plasma high-density lipoprotein cholesterol (HDL-C) levels are a strong, independent, but poorly understood risk factor for cardiovascular disease (CVD). Although this atherogenic lipid abnormality has been widely reported in Australia’s Indigenous peoples, Aboriginal and Torres Strait Islanders, the evidence has not come under systematic review. This review therefore examines published data for Indigenous Australians reporting 1) mean HDL-C levels for both sexes and 2) factors associated with low HDL-C.

Methods

PubMed, Medline and Informit ATSI Health databases were systematically searched between 1950 and 2012 for studies on Indigenous Australians reporting mean HDL-C levels in both sexes. Retrieved studies were evaluated by standard criteria. Low HDL-C was defined as: <1.0 mmol/L. Analyses of primary data associating measures of HDL-C with other CVD risk factors were also performed.

Results

Fifteen of 93 retrieved studies were identified for inclusion. These provided 58 mean HDL-C levels; 29 for each sex, most obtained in rural/regional (20%) or remote settings (60%) and including 51–1641 participants. For Australian Aborigines, mean HDL-C values ranged between 0.81-1.50 mmol/L in females and 0.76-1.60 mmol/L in males. Two of 15 studies reported HDL-C levels for Torres Strait Islander populations, mean HDL-C: 1.00 or 1.11 mmol/L for females and 1.01 or 1.13 mmol/L for males. Low HDL-C was observed only in rural/regional and remote settings - not in national or urban studies (n = 3) in either gender. Diabetes prevalence, mean/median waist-to-hip ratio and circulating C-reactive protein levels were negatively associated with HDL-C levels (all P < 0.05). Thirty-four per cent of studies reported lower mean HDL-C levels in females than in males.

Conclusions

Very low mean HDL-C levels are common in Australian Indigenous populations living in rural and remote communities. Inverse associations between HDL-C and central obesity, diabetes prevalence and inflammatory markers suggest a particularly adverse CVD risk factor profile. An absence of sex dichotomy in HDL-C levels warrants further investigation.

Factors influencing food choice in an Australian Aboriginal community

We explored with Aboriginal adults living in a remote Australian community the social context of food choice and factors perceived to shape food choice. An ethnographic approach of prolonged community engagement over 3 years was augmented by interviews. Our findings revealed that knowledge, health, and resources supporting food choice were considered "out of balance," and this imbalance was seen to manifest in a Western-imposed diet lacking variety and overrelying on familiar staples. Participants felt ill-equipped to emulate the traditional pattern of knowledge transfer through passing food-related wisdom to younger generations. The traditional food system was considered key to providing the framework for learning about the contemporary food environment. Practitioners seeking to improve diet and health outcomes for this population should attend to past and present contexts of food in nutrition education, support the educative role of caregivers, address the high cost of food, and support access to traditional foods.

Dietary patterns as predictors of successful ageing

OBJECTIVES

To examine associations between dietary patterns identified by factor analysis, and successful ageing.

DESIGN

Prospective cohort study with diet measured in 1990-4, and successful ageing in 2003-7. Ordered logistic regression with outcome determined as dead/usual ageing/successful ageing was used to examine associations with quintile groups of dietary factor scores.

PARTICIPANTS

Men and women (n=6308), without history of major illness at baseline, and aged >70 years at follow-up, or who had died before follow-up but would have been aged >70 at the commencement of follow-up, from the Melbourne Collaborative Cohort Study.

MEASUREMENTS

Frequencies of intake of 121 foods at baseline were collected in a food frequency questionnaire. Anthropometry and other health and lifestyle data were collected. At follow-up, questionnaire data relating to mental health, physical function and medical history were used to define successful ageing.

RESULTS

Four dietary factors were identified, characterized by higher loadings for (1) vegetables; (2) fruit, (3) feta, legumes, salad, olive oil, and inverse loadings for tea, margarine, cake, sweet biscuits and puddings; (4) meat, white bread, savoury pastry dishes and fried foods. In models excluding body size, the second factor 'Fruit' was positively associated with successful ageing (OR in top 20% vs lowest 20% of score 1.31, 95%CI (1.05-1.63), p trend across quintile groups 0.001); while the fourth factor 'Meat/fatty foods' was inversely associated (OR in top 20% vs lowest 20% of score 0.69, 95%CI (0.55-0.86), p trend across quintile groups 0.001). Factors 1 and 3 did not show significant associations with successful ageing. The association for 'Fruit' was little altered after adjustment for body size, while for 'Meat/fatty foods' the association was somewhat attenuated.

CONCLUSION

A dietary pattern including plenty of fruit while limiting meat and fried foods may improve the likelihood of ageing successfully.

Oral health behaviours and perceptions reported by Indigenous Australians living in Darwin, Northern Territory

OBJECTIVE

To describe the reported oral health behaviours and perceptions of Indigenous Australians living in Darwin, Northern Territory and to compare those with estimates for Darwin and Australia derived from the National Survey of Adult Oral Health (NSAOH).

PARTICIPANTS

A total of 181 Indigenous Australians aged 22 years and over living in Darwin, participating in screening for a wider randomised clinical trial, were included.

METHOD

Information on socio-demographic characteristics, oral health status including oral health behaviours and perceptions was collected using a questionnaire. Differences between the Darwin study (DS) participants and Australians in NSAOH were made based on non-overlapping 95% confidence intervals.

RESULTS

Almost 72% of DS participants had last seen a dentist over a year earlier, compared to 47% and 39% of NSAOH Darwin and Australian participants, respectively. A higher proportion of DS participants usually visited a dentist because of a problem than NSAOH Darwin and NSAOH Australian participants. A higher proportion of DS participants had avoided or delayed a dental visit because of cost than NSAOH participants. Over three times as many DS participants rated their oral health as fair/poor compared to NSAOH participants. A higher proportion of DS participants had perceived gum disease and one or more symptoms of gum disease than NSAOH participants. A higher proportion of DS participants experienced toothache, felt uncomfortable about appearance of their mouth and avoided eating because of oral problems than NSAOH participants.

CONCLUSIONS

A higher proportion of Indigenous Australians living in Darwin presented with non-optimal oral health behaviours and perceptions compared with both the Darwin and Australian general populations.

Optimisation modelling to assess cost of dietary improvement in remote Aboriginal Australia

BACKGROUND

The cost and dietary choices required to fulfil nutrient recommendations defined nationally, need investigation, particularly for disadvantaged populations.

OBJECTIVE

We used optimisation modelling to examine the dietary change required to achieve nutrient requirements at minimum cost for an Aboriginal population in remote Australia, using where possible minimally-processed whole foods.

DESIGN

A twelve month cross-section of population-level purchased food, food price and nutrient content data was used as the baseline. Relative amounts from 34 food group categories were varied to achieve specific energy and nutrient density goals at minimum cost while meeting model constraints intended to minimise deviation from the purchased diet.

RESULTS

Simultaneous achievement of all nutrient goals was not feasible. The two most successful models (A & B) met all nutrient targets except sodium (146.2% and 148.9% of the respective target) and saturated fat (12.0% and 11.7% of energy). Model A was achieved with 3.2% lower cost than the baseline diet (which cost approximately AUD$13.01/person/day) and Model B at 7.8% lower cost but with a reduction in energy of 4.4%. Both models required very large reductions in sugar sweetened beverages (-90%) and refined cereals (-90%) and an approximate four-fold increase in vegetables, fruit, dairy foods, eggs, fish and seafood, and wholegrain cereals.

CONCLUSION

This modelling approach suggested population level dietary recommendations at minimal cost based on the baseline purchased diet. Large shifts in diet in remote Aboriginal Australian populations are needed to achieve national nutrient targets. The modeling approach used was not able to meet all nutrient targets at less than current food expenditure.

Pregnancy And Neonatal Diabetes Outcomes in Remote Australia (PANDORA) Study

Background

Diabetes in pregnancy carries an increased risk of adverse pregnancy outcomes for both the mother and foetus, but it also provides an excellent early opportunity for intervention in the life course for both mother and baby. In the context of the escalating epidemic of chronic diseases among Indigenous Australians, it is vital that this risk is reduced as early as possible in the life course of the individual. The aims of the PANDORA Study are to: (i) accurately assess rates of diabetes in pregnancy in the Northern Territory (NT) of Australia, where 38% of babies are born to Indigenous mothers; (ii) assess demographic, clinical, biochemical, anthropometric, socioeconomic and early life development factors that may contribute to key maternal and neonatal birth outcomes associated with diabetes in pregnancy; and (iii) monitor relevant post-partum clinical outcomes for both the mothers and their babies.

Methods/Design

Eligible participants are all NT women with diabetes in pregnancy aged 16 years and over. Information collected includes: standard antenatal clinical information, diagnosis and management of diabetes in pregnancy, socio-economic status, standard clinical birth information (delivery, gestational age, birth weight, adverse antenatal and birth outcomes). Cord blood is collected at the time of delivery and detailed neonatal anthropometric measurements performed within 72 hours of birth. Information will also be collected regarding maternal post-partum glucose tolerance and cardio-metabolic risk factor status, breastfeeding and growth of the baby up to 2 years post-partum in the first instance.

Discussion

This study will accurately document rates and outcomes of diabetes in pregnancy in the NT of Australia, including the high-risk Indigenous Australian population. The results of this study should contribute to policy and clinical guidelines with the goal of reducing the future risk of obesity and diabetes in both mothers and their offspring.

"We need our own food, to grow our own veggies…" Remote Aboriginal food gardens in the Top End of Australia's Northern Territory

OBJECTIVE

Remote Aboriginal community gardens (gardens) frequently operate below their full potential. A set of gardening sustainability principles may improve their planning, operation and long-term sustainability. This paper aims to document the principles of sustainability of non-profit remote Aboriginal community gardens in the Top End of the Northern Territory.

METHODS

Throughout 2011, gardens in the Top End of the Northern Territory were visited. Interviews and observational data were used to explore the principles of garden sustainability with participants. Subsequent iterative thematic analysis informed development of a set of gardening sustainability principles.

RESULTS

Principles of sustainability included effective garden planning; community autonomy, consultation and engagement; growing community vetted crops; employing long-term, effective, culturally sensitive managers; long-term, transparent funding organisations and cycles; garden integration into existing food supply chains; culturally appropriate employment arrangements; and physical aspects of successful gardening.

CONCLUSIONS

This work uniquely consults gardeners, managers and Aboriginal and non-Aboriginal people of both genders in the largest reported study of its type, resulting in new and expanded findings, particularly including new social factors for gardening success.

IMPLICATIONS

Expanding the understanding of what makes gardens work to include the important social factors identified here may have merit.

Health outcomes of a subsidised fruit and vegetable program for Aboriginal children in northern New South Wales

OBJECTIVE

To evaluate the impact of a fruit and vegetable subsidy program on short-term health outcomes of disadvantaged Aboriginal children.

DESIGN, SETTING AND PARTICIPANTS

A before-and-after study involving clinical assessments, health record audits and blood testing of all children aged 0-17 2013s (n = 167) from 55 participating families at baseline and after 12 months at three Aboriginal community-controlled health services in New South Wales. All assessments were completed between December 2008 and September 2010.

INTERVENTION

A weekly box of subsidised fruit and vegetables linked to preventive health services and nutrition promotion at an Aboriginal Medical Service.

MAIN OUTCOME MEASURES

Change in episodes of illness, health service and emergency department attendances, antibiotic prescriptions and anthropometry.

RESULTS

There was a significant decrease in oral antibiotics prescribed (- 0.5 prescriptions/2013; 95% CI, - 0.8 to - 0.2) during 12 months of participation in the program compared with the 12 months before the program. The proportion of children classified as overweight or obese at baseline was 28.3% (38/134) and the proportion in each weight category did not change (P = 0.721) after 12 months. A small but significant increase in mean haemoglobin level (3.1 g/L; 95% CI, 1.4-4.8 g/L) was shown, although the proportion with iron deficiency (baseline, 41%; follow-up, 37%; P = 0.440) and anaemia (baseline, 8%; follow-up, 5%; P = 0.453) did not change significantly.

CONCLUSION

it and vegetable subsidy program was associated with improvements in some indicators of short-term health status among disadvantaged Aboriginal children. A controlled trial is warranted to investigate the sustainability and feasibility of healthy food subsidy programs in Australia.

Effects of fish oil supplementation on learning and behaviour of children from Australian Indigenous remote community schools: a randomised controlled trial

Omega-3 fatty acids are essential for brain function. We recruited 409 children aged 3-13 years (M=8.27, SD=2.17) for a randomised controlled trial supplementing with placebo or fish oil capsules (providing 750mg docosahexaenoic plus eicosapentaenoic acids, and 60mg gamma linolenic acid/school day) for 20 school weeks (Phase 1) followed by one-way crossover to fish oil (Phase 2). Children undertook assessments of reading, spelling and non-verbal cognitive development (Draw-A-Person) at baseline, 20 and 40 weeks. Teachers completed Conners Behaviour Rating Scales (CBRS). The treatment group showed improvements in Draw-A-Person compared with the placebo during Phase 1 (p=0.029), with strongest effects in Indigenous 7-12 year olds (p=0.008). The placebo group showed significant within-group improvements after switching to treatment (p<0.001). There was no treatment effect for reading or spelling, and CBRS data were unable to be analysed. These findings may be understood in the context that sustained school attendance and nutrition interact to produce school-related achievement.

Hypertriglyceridemic waist and newly-diagnosed diabetes among remote-dwelling Indigenous Australians

AIMS

Hypertriglyceridemic waist (HTgW) is predictive of cardiovascular disease. The HTgW relationship with diabetes is little studied.

METHODS

This study analysed data from diabetes and cardiovascular risk factor screening programmes in remote Indigenous Australian settlements. Elevated waist girth (EW) was defined as ≥90 cm for men (n = 1134) or ≥80 cm for women (n = 1313). Hypertriglyceridemia (ETg) was defined as ≥1.7 mmol/L. Diabetes was defined as fasting plasma glucose ≥7.0 mmol/L. Body mass index (BMI) was categorised as <22, 22-24.9 and >25.0 kg/m(2). Logistic regression was used to analyse the odds of newly-diagnosed diabetes for individuals with either HTgW, ETg or EW, relative to individuals with values below cut-offs.

RESULTS

The prevalence of HTgW was 33.2% for men and 34.8% for women. Accounting for age-group and gender, newly-diagnosed diabetes was associated (odds ratio (OR) (95% confidence interval)) with HTgW: 9.6 (6.6, 13.8). The relationship remained strong after accounting for the covariates BMI and smoking (OR = 4.9 (2.7, 8.8)). In BMI-stratified analyses the strongest odds were observed for the lowest category (<22 kg/m(2): OR = 12.9 (4.0, 41.7)).

CONCLUSIONS

HTgW has a high prevalence and is associated with newly-diagnosed diabetes in Indigenous people, particularly those with BMI <22 kg/m(2), whom clinicians might not normally consider for screening.

The metabolic syndrome and CVD outcomes for a central Australian cohort

We investigated if the metabolic syndrome (MetS) and its component risk factors predict cardiovascular disease (CVD) for Aboriginal people from central Australia. WHO (HR 2.83), NCEP (1.80) and IDF (2.47) definitions of the MetS all had positive associations with CVD, however offered little above individual MetS components for hyperglycaemia.

Diabetes and ageing in the Melbourne Collaborative Cohort Study (MCCS)

AIMS

To examine the association between diabetes, and ageing 12 years later.

METHODS

Subjects reporting angina, cancer, heart attack or stroke at baseline (1990-1994) were excluded. Diabetes at baseline was identified by self-report or elevated plasma glucose (≥ 7.0 mmol/l fasting or ≥ 11.1 mmol/l non-fasting). 6431 eligible men and women had survived to age 70 years at follow-up (2003-2007), and 5704 with complete data were included in these analyses. Those without ischemic heart disease, stroke, and cancer, no perceived major difficulty with physical functioning, and no evidence of psychological distress were considered to have aged successfully, irrespective of diabetes at follow-up (n=1271). Logistic regression was used to examine the independent association between baseline diabetes and successful ageing.

RESULTS

At baseline 216 eligible people were identified with diabetes. This was inversely associated with successful ageing at follow-up independent of smoking, physical activity, alcohol use and obesity (OR 0.65, 95% 0.42-0.99), Of the people with diabetes at follow-up, only 12.5% did not have another condition characteristic of usual ageing, compared with 22.7% of people who did not have diabetes.

CONCLUSIONS

Diabetes is strongly associated with factors characterising less successful ageing, suggesting that the impact of diabetes may be larger than currently estimated.

Similarities and differences in cardiometabolic risk factors among remote Aboriginal Australian and Canadian cohorts

AIM

Indigenous populations of Australia and Canada experience disproportionately high rates of chronic disease. We hypothesized that despite the common outcome of increased diabetes prevalence, differences in cardiometabolic risk profile may exist between these populations.

METHODS

We compared community-based data on cardiometabolic risks in Aboriginal Australians (n=297 without, 45 with diabetes), and Aboriginal Canadians (n=409 without, 87 with diabetes).

RESULTS

Despite strikingly lower weight (62 vs 83 kg, p<0.0001) and body mass index (BMI, 22 vs 29 kg/m(2), p<0.0001), Aboriginal Australians without diabetes had similar waist-hip ratio (WHR, 0.91 vs 0.91, p=0.732), lower HDL-cholesterol (0.97 vs 1.25 mmol/L, p<0.0001) and higher HbA1c (5.4 vs 5.2%, p<0.0001) than Aboriginal Canadians without diabetes. Waist was the obesity measure most strongly related to diabetes or cardiometabolic risk in Australians while BMI performed similarly to other obesity measures only in Canadians. Multiple regression of HbA1c revealed age and fasting glucose as independent predictors in each study group, with the addition of WHR in Aboriginal Australians.

CONCLUSION

The notable finding was that waist or WHR are preferred obesity measures to appropriately reflect cardiometabolic risk in Aboriginal Australians, who although leaner by BMI criteria, displayed a similarly adverse risk profile to Aboriginal Canadians. Waist or WHR should be routinely included in clinical assessment in these high-risk populations.

Plasma retinol: a novel marker for cardiovascular disease mortality in Australian adults

BACKGROUND AND AIMS

Vitamin A affects inflammation and immune function and is thus a factor of interest in relation to cardiovascular disease (CVD). As vitamin A circulates in the plasma in the form of retinol, this study aims to describe the relationship between plasma retinol and the 5-year incidence of CVD mortality.

METHODS AND RESULTS

Community-dwelling adults (n = 441, 45% with type 2 diabetes) were recruited in Melbourne, assessed at baseline and followed for 5 years. At baseline, CVD risk factors were assessed by clinical evaluation, by personal lifestyle questionnaire and from biochemistry (plasma fasting glucose, lipids, total homocysteine, C-reactive protein, retinol and carotenoids plus the urinary albumin excretion rate over 24 h.). Dietary intake was assessed by a validated food frequency questionnaire. CVD mortality over 5-years was determined by consulting state or national registries. The majority of participants had adequate plasma retinol concentrations (≥30 μg/dL). The final Cox regression model indicated that those in the highest tertile of plasma retinol (mean ± SD) 76 ± 14 μg/dL) had a significantly lower risk of 5-year CVD mortality (hazard ratio 0.27 [95% confidence interval 0.11, 0.68], P = 0.005), an effect that was not readily explained in terms of traditional CVD risk factors or dietary intake.

CONCLUSION

In well-nourished older Australian adults, plasma retinol was inversely associated with CVD mortality via mechanisms apparently unrelated to established CVD risk factors and dietary intake.

Longitudinal displacement of the carotid wall and cardiovascular risk factors: associations with aging, adiposity, blood pressure and periodontal disease independent of cross-sectional distensibility and intima-media thickness

The recently discovered longitudinal displacement of the common carotid arterial wall (i.e., the motion along the same plane as the blood flow), may be associated with incident cardiovascular events and represents a novel and relevant clinical information. At present, there have only been a few studies that have been conducted to investigate this longitudinal movement. We propose here a method to assess noninvasively the wall bi-dimensional (two-dimensional [2-D], cross-sectional and longitudinal) motion and present an original approach that combines a robust speckle tracking scheme to guidance by minimal path contours segmentation. Our method is well suited to large clinical population studies as it does not necessitate strong imaging prerequisites. The aim of this study is to describe the association between the longitudinal displacement of the carotid arterial wall and cardiovascular risk factors, among which periodontal disease. Some 126 Indigenous Australians with periodontal disease, an emerging risk factor, and 27 healthy age- and sex-matched non-indigenous control subjects had high-resolution ultrasound scans of the common carotid artery. Carotid intima-media thickness and arterial wall 2-D motion were then assessed using our method in ultrasound B-mode sequences. Carotid longitudinal displacement was markedly lower in the periodontal disease group than the control group (geometric mean (IQR): 0.15 mm (0.13) vs. 0.42 mm (0.30), respectively; p < 0.0001), independent of cardiovascular risk factors, cross-sectional distensibility and carotid intima-media thickness (p < 0.0001). A multivariable model indicated that the strongest correlates of carotid longitudinal displacement in adults with periodontal disease were age (β-coefficient = -.235, p = .03), waist (β-coefficient = -.357, p = 0.001), and pulse pressure (β-coefficient = .175, p = 0.07), independent of other cardiovascular risk factors, cross-sectional distensibility and pulse wave velocity. Carotid longitudinal displacement, estimated with our approach, is impaired in the periodontal disease group, independent of established cardiovascular risk factors and other noninvasive measures of arterial stiffness, and may represent an important marker of cardiovascular risk.

Obesity: lessons from evolution and the environment

The 9th Stock Conference acknowledged the complex background of genetic, cultural, environmental and evolutionary factors of obesity. Gene-environment interactions underlie the flexibility in body-weight and body-fat regulation, illustrated by the hunter-gatherers' feast and famine lifestyle, the variation in physical activity over the lifespan being highest at reproductive age, the variation in energy intake through 'eating in the absence of hunger', while running the risk of exceeding the capacity of triacylglyceride storage, leading to lipotoxicity and metabolic problems. Perinatal metabolic programming for obesity via epigenetic changes in response to a 'Western diet' results in production of lipid-poor milk and metabolically efficient pups, contributing to the perpetuation of obesity throughout generations. Evolutionary insight from comparative physiology and ecology indicates that over generations activity-induced energy expenditure has remained the same compared to wild mammals, that energy balance might be dependant on protein balance, while the function of taste changed from detection of poison or energy to social drinking and social behaviour. At present, the impact of assortative mating on obesity prevalence is unambiguously positive. The complexity that appeared can only be fully appreciated by setting the data into the context of our evolutionary history.

Increased bone mineral density in Aboriginal and Torres Strait Islander Australians: impact of body composition differences

Bone mineral density (BMD) has been reported to be both higher and lower in Indigenous women from different populations. Body composition data have been reported for Indigenous Australians, but there are few published BMD data in this population. We assessed BMD in 161 Indigenous Australians, identified as Aboriginal (n=70), Torres Strait Islander (n=68) or both (n=23). BMD measurements were made on Norland-XR46 (n=107) and Hologic (n=90) dual-energy X-ray absorptiometry (DXA) machines. Norland BMD and body composition measurements in these individuals, and also in 36 Caucasian Australians, were converted to equivalent Hologic BMD (BMD(H)) and body composition measurements for comparison. Femoral neck (FN) and lumbar spine Z-scores were high in Indigenous participants (mean FN Z-score: Indigenous men +0.98, p<0.0001 vs. mean zero; Indigenous women +0.82, p<0.0001 vs. mean zero). FN BMD(H) was higher in Aboriginal and/or Torres Strait Islander than Caucasian participants, after adjusting for age, gender, diabetes and height and remained higher in men after addition of lean mass to the model. We conclude that FN BMD is higher in Aboriginal and/or Torres Strait Islander Australians than Caucasian Australian reference ranges and these differences still remained significant in men after adjustment for lean mass. It remains to be seen whether these BMD differences translate to differences in fracture rates.

Cardiovascular disease risk profile and microvascular complications of diabetes: comparison of Indigenous cohorts with diabetes in Australia and Canada

BACKGROUND

Indigenous populations of Australia and Canada experience disproportionately high rates of chronic disease. Our goal was to compare cardiovascular (CVD) risk profile and diabetes complications from three recent comprehensive studies of diabetes complications in different Indigenous populations in Australia and Canada.

METHODS

We compared participants from three recent studies: remote Indigenous Australians (2002-2003, n = 37 known diabetes), urban Indigenous Australians (2003-2005, n = 99 known diabetes), and remote Aboriginal Canadians (2001-2002, n = 188 known diabetes).

RESULTS

The three groups were similar for HbA1c, systolic BP, diabetes duration. Although leaner by body-mass-index criteria, remote Indigenous Australians displayed a more adverse CVD risk profile with respect to: waist-hip-ratio (1.03, 0.99, 0.94, remote Indigenous Australians, urban Indigenous Australians, remote Canadians, p < 0.001); HDL-cholesterol (0.82, 0.96, 1.17 mmol/L, p < 0.001); urine albumin-creatinine-ratio (10.3, 2.4, 4.5 mg/mmol); and C-reactive protein. With respect to diabetes complications, microalbuminuria (50%, 25%, 41%, p = 0.001) was more common among both remote groups than urban Indigenous Australians, but there were no differences for peripheral neuropathy, retinopathy or peripheral vascular disease.

CONCLUSIONS

Although there are many similarities in diabetes phenotype in Indigenous populations, this comparison demonstrates that CVD risk profiles and diabetes complications may differ among groups. Irrespective, management and intervention strategies are required from a young age in Indigenous populations and need to be designed in consultation with communities and tailored to community and individual needs.

The effect of a periodontal intervention on cardiovascular risk markers in Indigenous Australians with periodontal disease: the PerioCardio study

Background

Indigenous Australians experience an overwhelming burden of chronic disease, including cardiovascular diseases. Periodontal disease (inflammation of the tissues surrounding teeth) is also widespread, and may contribute to the risk of cardiovascular diseases via pathogenic inflammatory pathways. This study will assess measures of vascular health and inflammation in Indigenous Australian adults with periodontal disease, and determine if intensive periodontal therapy improves these measures over a 12 month follow-up. The aims of the study are: (i) to determine whether there is a dose response relationship between extent and severity of periodontal disease and measures of vascular health and inflammation among Indigenous Australian adults with moderate to severe periodontal disease; and (ii) to determine the effects of periodontal treatment on changes in measures of vascular health and inflammation in a cohort of Indigenous Australians.

Methods/Design

This study will be a randomised, controlled trial, with predominantly blinded assessment of outcome measures and blinded statistical analysis. All participants will receive the periodontal intervention benefits (with the intervention delayed 12 months in participants who are randomised to the control arm). Participants will be Indigenous adults aged ≥25 years from urban centres within the Top End of the Northern Territory, Australia. Participants assessed to have moderate or severe periodontal disease will be randomised to the study's intervention or control arm. The intervention involves intensive removal of subgingival and supragingival calculus and plaque biofilm by scaling and root-planing. Study visits at baseline, 3 and 12 months, will incorporate questionnaires, non-fasting blood and urine samples, body measurements, blood pressure, periodontal assessment and non-invasive measures of vascular health (pulse wave velocity and carotid intima-media thickness). Primary outcome measures are pulse wave velocity and carotid intima-media thickness.

Discussion

The study will assess the periodontal-cardiovascular disease relationship among Indigenous Australian adults with periodontal disease, and the effectiveness of an intervention aimed at improving periodontal and cardiovascular health. Efforts to understand and improve Indigenous oral health and cardiovascular risk may serve as an important means of reducing the gap between Indigenous and non-Indigenous health in Australia.

Trial Registration

Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12610000817044

Can the Mediterranean diet lower HbA1c in type 2 diabetes? Results from a randomized cross-over study

BACKGROUND AND AIMS

To investigate the impact of a diet modeled on the traditional Cretan Mediterranean diet on metabolic control and vascular risk in type 2 diabetes.

METHODS AND RESULTS

Twenty-seven subjects (47-77 yrs) with type 2 diabetes were randomly assigned to consume either the intervention diet ad libitum or their usual diet for 12 weeks and then cross over to the alternate diet. Most of the meals and staple foods for the intervention diet were provided. Lipids, glycemic variables, blood pressure, homocysteine, C-reactive protein, plasma carotenoids and body composition (anthropometry and dual energy X-ray absorptiometry) were assessed at baseline, and at the end of both diet periods. Dietary adherence was monitored using plasma carotenoid and fatty acid (FA) analysis, complemented by diet diaries. Compared with usual diet, on the ad libitum Mediterranean intervention diet glycosylated haemoglobin fell from 7.1% (95% CI: 6.5-7.7) to 6.8% (95% CI: 6.3-7.3) (p=0.012) and diet quality improved significantly [plant:animal (g/day) food ratio increased from 1.3 (95% CI: 1.1-1.5) to 5.4 (95% CI: 4.3-6.6) (p<0.001)], plasma lycopene and lutein/zeaxanthin increased (36% and 25%, respectively), plasma saturated and trans FAs decreased, and monounsaturated FAs increased.

CONCLUSION

A traditional moderate-fat Mediterranean diet improves glycemic control and diet quality in men and women with well-controlled type 2 diabetes, without adverse effects on weight.

Does a Mediterranean diet reduce the mortality risk associated with diabetes: evidence from the Melbourne Collaborative Cohort Study

BACKGROUND AND AIMS

Diabetes is a risk factor for cardiovascular disease (CVD), yet southern European migrants to Australia with high rates of type 2 diabetes have relatively low CVD mortality. Our aim was to determine whether a Mediterranean style diet could reduce mortality in people with diabetes.

METHODS AND RESULTS

Participants included 16,610 males and 23,860 females from the Melbourne Collaborative Cohort Study; 25% were born in Greece or Italy, and 2150 had previously been diagnosed with diabetes or had elevated blood glucose at baseline (1990-94). Data on demographic, behavioral and physical risk factors were also collected. A personal Mediterranean Diet Score (MDS) was calculated using data from a validated 121-item food frequency questionnaire. Total and CVD mortality data were available up to 2003. Diabetes (new and known) at baseline, was associated with total mortality (men HR 1.43, 95%CI 1.26-1.62; women HR 1.86 95%CI 1.58-2.18), and CVD mortality (men HR 1.53, 95%CI 1.21-1.94; women HR 2.10 95%CI 1.48-2.97) in multivariate models. There was no evidence that glucose tolerance modified the associations between MDS and total or CVD mortality (p interaction all > 0.16). The HRs for total mortality per unit of MDS were 0.96 (95% CI 0.93-0.99) in men and 0.94 (95% CI 0.92-0.97) in women. The HRs for CVD mortality per unit of MDS were 0.94 (95% CI 0.89-0.99) in men and 0.94 (95% CI 0.87-1.01) in women.

CONCLUSION

Our results add to the evidence supporting the benefit of a Mediterranean style diet for people with type 2 diabetes.

NMR-determined lipoprotein subclass profile is associated with dietary composition and body size

BACKGROUND AND AIMS

Dyslipidemia is influenced by diet and body habitus. The Nuclear Magnetic Resonance spectroscopy lipoprotein subclass profile (NMR-LSP) is associated with diabetes and its vascular complications; and an NMR-LSP featuring large VLDL particles and small LDL and HDL particles is linked with cardiovascular disease (CVD). Thus interventions which favourably modify NMR-LSP may reduce risk for diabetes, its complications and CVD. The study aim was to investigate the associations between NMR-LSP, dietary composition and body size measures using data from the Melbourne Collaborative Cohort Study (MCCS).

METHODS AND RESULTS

NMR-LSP was assessed in 313 men and 403 women (median age 54 years) randomly selected from a community-based cohort study. Diet was assessed using a specifically developed food frequency questionnaire (FFQ), and body size was assessed by body mass index (BMI) or waist:hips ratio (WHR). To simplify the 15 NMR-LSP variables, factor analysis was used to derive a single factor. Multivariate linear regression with this factor score as the dependent variable demonstrated that in men, total PUFA and n-6 dietary fat intake and BMI were associated with a more atherogenic NMR-LSP pattern; while in women dietary glycemic index and WHR demonstrated positive associations, and n-3 fat intake an inverse association.

CONCLUSIONS

We developed a single factor score to summarize the NMR-LSP that has the benefit of combining all aspects of the NMR-LSP and accounting for correlations between them. We have shown correlations between the NMR-LSP and body size and dietary composition.

Plasma carotenoids are associated with socioeconomic status in an urban Indigenous population: an observational study

Background

Indigenous Australians experience poorer health than other Australians. Poor diet may contribute to this, and be related to their generally lower socioeconomic status (SES). Even within Indigenous populations, SES may be important. Our aim was to identify factors associated with plasma carotenoids as a marker of fruit and vegetable intake among urban dwelling Indigenous Australians, with a particular focus on SES.

Methods

Cross sectional study in urban dwelling Indigenous Australians participating in the DRUID (Darwin Region Urban Indigenous Diabetes) Study. An SES score, based on education, employment, household size, home ownership and income was computed and plasma carotenoids measured by high performance liquid chromatography in 897 men and women aged 15 - 81 years (mean 36, standard deviation 15). Linear regression analysis was used to determine the relationship between SES and plasma carotenoids, adjusting for demographic, health and lifestyle variables, including frequency of intakes of food groups (fruit, vegetables, takeaway foods, snacks and fruit/vegetable juice).

Results

SES was positively associated with plasma concentrations of lutein/zeaxanthin (p trend <0.001), lycopene (p trend = 0.001), α- and ß-carotene (p trend = 0.019 and 0.026 respectively), after adjusting for age, sex, glucose tolerance status, smoking, alcohol use, hypercholesterolemia, dyslipidemia, self-reported health, waist to hip ratio and body mass index. These associations remained after adjustment for self-reported frequency of intake of fruit, vegetables, takeaway foods and fruit juice, which all showed some association with plasma carotenoids. Even in the highest SES quintile, concentrations of all carotenoids (except lycopene) were lower than the mean concentrations in a non-Indigenous population.

Conclusions

Even within urban Indigenous Australians, higher SES was associated with higher concentrations of plasma carotenoids. Low plasma carotenoids have been linked with poor health outcomes; increasing accessibility of fruit and vegetables, as well as reducing smoking rates could increase concentrations and otherwise improve health, but our results suggest there may be additional factors contributing to lower carotenoid concentrations in Indigenous Australians.

Abdominal obesity and other risk factors largely explain the high CRP in indigenous Australians relative to the general population, but not gender differences: a cross-sectional study

Background

Previous studies reported high C-reactive protein (CRP) levels in Indigenous Australians, which may contribute to their high risk of cardiovascular disease. We compared CRP levels in Indigenous Australians and the general population, accounting for obesity and other risk factors.

Methods

Cross-sectional study of CRP and risk factors (weight, height, waist and hip circumferences, blood pressure, lipids, blood glucose, and smoking status) in population-based samples from the Diabetes and Related conditions in Urban Indigenous people in the Darwin region (DRUID) study, and the Australian Diabetes, Obesity and Lifestyle study (AusDiab) follow-up.

Results

CRP concentrations were higher in women than men and in DRUID than AusDiab. After multivariate adjustment, including waist circumference, the odds of high CRP (>3.0 mg/L) in DRUID relative to AusDiab were no longer statistically significant, but elevated CRP was still more likely in women than men. After adjusting for BMI (instead of waist circumference) the odds for elevated CRP in DRUID participants were still higher relative to AusDiab participants among women, but not men. Lower HDL cholesterol, impaired glucose tolerance (IGT), and higher diastolic blood pressure were associated with having a high CRP in both men and women, while current smoking was associated with high CRP in men but not women.

Conclusions

High concentrations of CRP in Indigenous participants were largely explained by other risk factors, in particular abdominal obesity. Irrespective of its independence as a risk factor, or its aetiological association with coronary heart disease (CHD), the high CRP levels in urban Indigenous women are likely to reflect increased vascular and metabolic risk. The significance of elevated CRP in Indigenous Australians should be investigated in future longitudinal studies.

Fibrinogen and associated risk factors in a high-risk population: urban Indigenous Australians, the DRUID Study

Background

Epidemiological evidence suggests that fibrinogen and CRP are associated with coronary heart disease risk. High CRP in Indigenous Australians has been reported in previous studies including our 'Diabetes and Related diseases in Urban Indigenous population in Darwin region' (DRUID) Study. We studied levels of fibrinogen and its cross-sectional relationship with traditional and non-traditional cardiovascular risk factors in an urban Indigenous Australian cohort.

Methods

Fibrinogen data were available from 287 males and 628 females (aged ≥ 15 years) from the DRUID study. Analysis was performed for associations with the following risk factors: diabetes, HbA1c, age, BMI, waist circumference, waist-hip ratio, total cholesterol, triglyceride, HDL cholesterol, C-reactive protein, homocysteine, blood pressure, heart rate, urine ACR, smoking status, alcohol abstinence.

Results

Fibrinogen generally increased with age in both genders; levels by age group were higher than those previously reported in other populations, including Native Americans. Fibrinogen was higher in those with than without diabetes (4.24 vs 3.56 g/L, p < 0.001). After adjusting for age and sex, the following were significantly associated with fibrinogen: BMI, waist, waist-hip ratio, systolic blood pressure, heart rate, fasting triglycerides, HDL cholesterol, HbA1c, CRP, ACR and alcohol abstinence. On multivariate regression (age and sex-adjusted) CRP and HbA1c were significant independent predictors of fibrinogen, explaining 27% of its variance; CRP alone explained 25% of fibrinogen variance. On factor analysis, both CRP and fibrinogen clustered with obesity in women (this factor explained 20% of variance); but in men, CRP clustered with obesity (factor explained 18% of variance) whilst fibrinogen clustered with HbA1c and urine ACR (factor explained 13% of variance).

Conclusions

Fibrinogen is associated with traditional and non-traditional cardiovascular risk factors in this urban Indigenous cohort and may be a useful biomarker of CVD in this high-risk population. The apparent different associations of fibrinogen with cardiovascular disease risk markers in men and women should be explored further.