Vitamin D status is inversely associated with markers of risk for type 2 diabetes: A population based study in Victoria, Australia.

A growing body of evidence suggests a protective role of vitamin D on the risk of type 2 diabetes mellitus (T2DM). We investigated this relationship in a population sample from one Australian state. The data of 3,393 Australian adults aged 18-75 years who participated in the 2009-2010 Victorian Health Monitor survey was analyzed. Socio-demographic information, biomedical variables, and dietary intakes were collected and fasting blood samples were analyzed for 25, hydroxycholecalciferol (25OHD), HbA1c, fasting plasma glucose (FPG), and lipid profiles. Logistic regression analyses were used to evaluate the association between tertiles of serum 25OHD and categories of FPG (<5.6 mmol/L vs. 5.6-6.9 mmol/L), and HbA1c (<5.7% vs. 5.7-6.4%). After adjusting for social, dietary, biomedical and metabolic syndrome (MetS) components (waist circumference, HDL cholesterol, triglycerides, and blood pressure), every 10 nmol/L increment in serum 25OHD significantly reduced the adjusted odds ratio (AOR) of a higher FPG [AOR 0.91, (0.86, 0.97); p = 0.002] and a higher HbA1c [AOR 0.94, (0.90, 0.98); p = 0.009]. Analysis by tertiles of 25OHD indicated that after adjustment for socio-demographic and dietary variables, those with high 25OHD (65-204 nmol/L) had reduced odds of a higher FPG [AOR 0.60, (0.43, 0.83); p = 0.008] as well as higher HbA1c [AOR 0.67, (0.53, 0.85); p = 0.005] compared to the lowest 25OHD (10-44 nmol/L) tertile. On final adjustment for other components of MetS, those in the highest tertile of 25OHD had significantly reduced odds of higher FPG [AOR 0.61, (0.44, 0.84); p = 0.011] and of higher HbA1c [AOR 0.74, (0.58, 0.93); p = 0.041] vs. low 25OHD tertile. Overall, the data support a direct, protective effect of higher 25OHD on FPG and HbA1c; two criteria for assessment of risk of T2DM.

The associations of vitamin D status and dietary calcium with the metabolic syndrome: an analysis of the Victorian Health Monitor survey.

OBJECTIVE: To examine the associations between serum 25-hydroxyvitamin D (25(OH)D), dietary Ca intake and presence of the metabolic syndrome (MetS). DESIGN: A stratified cluster sample of a population aged 18-75 years from the Victorian Health Monitor survey. SETTING: Non-institutionalized adults living in private dwellings in Victoria, Australia. SUBJECTS: Adults (n 3404) with complete data and without type 1 or type 2 diabetes. RESULTS: Adjusted for sociodemographic factors, physical characteristics and dietary covariates including Ca intake, every 10 nmol/l increase in serum 25(OH)D was significantly associated with decreased odds of MetS (adjusted odds ratio (AOR)=0·85, 95 % CI 0·80, 0·89; P<0·001). Relative to the low 25(OH)D tertile (median 33 nmol/l), there was a progressive decrease in odds of MetS that reached significance with the high 25(OH)D tertile (median 77 nmol/l; AOR=0·35, 95 % CI 0·26, 0·48; P<0·001). Every 500 mg/d increase in Ca intake adjusted for 25(OH)D did not reduce odds of MetS (AOR=0·81, 95 % CI 0·66, 1·06; P=0·141) but approached significance if unadjusted for 25(OH)D in the final model (AOR=0·81, 95 % CI 0·64, 1·02; P=0·073). No significant effect was obtained for tertiles of Ca intake. However, Ca and vitamin D tertile combinations suggested a beneficial effect of high Ca (median 1233 mg/d) only at low and medium 25(OH)D. The high 25(OH)D tertile was associated with significantly decreased odds of MetS regardless of Ca intake. CONCLUSIONS: A high vitamin D status significantly reduced the odds of MetS. A high Ca intake may have a similar favourable outcome but only at lower circulating concentrations of 25(OH)D.

The association of vitamin D status and dietary calcium intake with individual components of the metabolic syndrome: a population-based study in Victoria, Australia.

This study examined the associations between 25-hydroxyvitamin D (25-OHD), dietary calcium (Ca) intake, and individual components of the metabolic syndrome (MetS). METHODS: We analyzed a population-based sample of 18-75-year-old adults (n=3387) from the Victorian Health Monitor survey. RESULTS: After adjustment for sociodemographic, physical, and dietary factors, as well as other MetS components, every 10 nmol/l increment in 25-OHD was associated with reduced adjusted odds ratio (AOR) of elevated triglycerides (TG) [AOR: 0.79, 95% confidence interval (CI): 0.74-0.84, P<0.001], and higher fasting plasma glucose (AOR: 0.91, 95% CI: 0.86-0.96, P=0.002). After adjustment for confounders, every 500 mg/day increment in dietary Ca intake significantly reduced the odds of elevated diastolic blood pressure (AOR: 0.80, 95% CI: 0.66-0.99, P=0.038). When nine combinations of 25-OHD and Ca tertiles were examined, certain combinations were associated with reduced AOR for elevated TG (P<0.001), when referenced against the combination of low 25-OHD (median: 33 nmol/l) and low Ca (median: 579 mg/day). At low 25-OHD, increasing Ca intake decreased the AOR for low high-density lipoprotein cholesterol in a dose-dependent manner, but at high 25-OHD; such effects of Ca were blunted. CONCLUSION: Higher vitamin D status and Ca intake or their combination were associated with reduced odds for a number of individual MetS components.

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.

Estimating human papillomavirus vaccination coverage among young women in Victoria and reasons for non-vaccination.

UNLABELLED: Background Adult Australian women aged 18 to 26 years were offered human papillomavirus (HPV) vaccine in a mass catch up campaign between 2007 and 2009. Not all doses administered were notified to Australia's HPV vaccine register and not all young women commenced or completed the vaccine course. METHODS: We surveyed vaccine age-eligible women as part of the Victorian Population Health Survey 2011-2012, a population based telephone survey, to ascertain self-reported vaccine uptake and reasons for non-vaccination or non-completion of vaccination among young women resident in the state of Victoria, Australia. RESULTS: Among 956 women surveyed, 62.3 per cent (57.8-66.6%) had been vaccinated against HPV and coverage with three doses was estimated at 53.7 per cent (49.1-58.2%). These estimates are higher than register-based estimates for the same cohort, which were 57.8 per cent and 37.2 per cent respectively. A lack of awareness about needing three doses and simply forgetting, rather than fear or experience of side effects, were the most common reasons for failure to complete all three doses. Among women who were not vaccinated, the most frequent reasons were not knowing the vaccine was available, perceiving they were too old to benefit, or not being resident in Australia at the time. CONCLUSIONS: It is likely that at least half of Victoria's young women were vaccinated during the catch-up program. This high level of coverage is likely to explain the marked reductions in HPV infection, genital warts and cervical disease already observed in young women in Victoria.

A lower than expected adult Victorian community attack rate for pandemic (H1N1) 2009.

OBJECTIVES: To determine the community seropositivity of pandemic (H1N1) 2009 influenza in order to estimate immunity and the community attack rate. METHODS: Selected clusters of participants (n=706) in the 'Victorian Health Monitor' (VHM), from whom blood samples were taken between August and October 2009, were tested opportunistically for antibodies to pandemic (H1N1) 2009 influenza virus. A titre of > or = 1:40 was chosen as the cut-off for recording seropositivity. The proportion (95% CI) of seropositive participants, aged 18 to <65 years of age, were computed for groups of census collection districts (CDs) across metropolitan Melbourne. RESULTS: The observed pandemic (H1N1) 2009 seropositivity rates for all CDs tested in metropolitan Melbourne was 16.0% (95% CI:12.9-19.1%); in northern Melbourne subset was 14.4% (95% CI:12.4-16.3%); and in eastern subset was 16.2% (95% CI:9.7-22.6%). The pre-pandemic (H1N1) 2009 positivity rate was estimated at 6%. CONCLUSION: Given this study's estimate of 16.0% seropositivity in adults in metropolitan Melbourne, and given the WHO laboratory's estimate of 6% pre-pandemic positivity, the estimated adult community attack rate was 10% for metropolitan Melbourne. IMPLICATIONS: This community attack rate is lower than anticipated and suggests that levels of immunity to Pandemic (H1N1) 2009 might be lower than anticipated. Although limited by a low response rate of 34%, this study suggests low adult seropositivity, which may be useful for public health professionals when encouraging the community to get vaccinated.

Study Protocol--accurate assessment of kidney function in Indigenous Australians: aims and methods of the eGFR study.

BACKGROUND: There is an overwhelming burden of cardiovascular disease, type 2 diabetes and chronic kidney disease among Indigenous Australians. In this high risk population, it is vital that we are able to measure accurately kidney function. Glomerular filtration rate is the best overall marker of kidney function. However, differences in body build and body composition between Indigenous and non-Indigenous Australians suggest that creatinine-based estimates of glomerular filtration rate derived for European populations may not be appropriate for Indigenous Australians. The burden of kidney disease is borne disproportionately by Indigenous Australians in central and northern Australia, and there is significant heterogeneity in body build and composition within and amongst these groups. This heterogeneity might differentially affect the accuracy of estimation of glomerular filtration rate between different Indigenous groups. By assessing kidney function in Indigenous Australians from Northern Queensland, Northern Territory and Western Australia, we aim to determine a validated and practical measure of glomerular filtration rate suitable for use in all Indigenous Australians. METHODS/DESIGN: A cross-sectional study of Indigenous Australian adults (target n = 600, 50% male) across 4 sites: Top End, Northern Territory; Central Australia; Far North Queensland and Western Australia. The reference measure of glomerular filtration rate was the plasma disappearance rate of iohexol over 4 hours. We will compare the accuracy of the following glomerular filtration rate measures with the reference measure: Modification of Diet in Renal Disease 4-variable formula, Chronic Kidney Disease Epidemiology Collaboration equation, Cockcroft-Gault formula and cystatin C- derived estimates. Detailed assessment of body build and composition was performed using anthropometric measurements, skinfold thicknesses, bioelectrical impedance and a sub-study used dual-energy X-ray absorptiometry. A questionnaire was performed for socio-economic status and medical history. DISCUSSION: We have successfully managed several operational challenges within this multi-centre complex clinical research project performed across remote North, Western and Central Australia. It seems unlikely that a single correction factor (similar to that for African-Americans) to the equation for estimated glomerular filtration rate will prove appropriate or practical for Indigenous Australians. However, it may be that a modification of the equation in Indigenous Australians would be to include a measure of fat-free mass.

Impact of pandemic (H1N1) 2009 influenza on critical care capacity in Victoria.

OBJECTIVE: To describe the demand for critical care hospital admissions in Victoria resulting from the rapid rise in the number of pandemic (H1N1) 2009 influenza cases, and to describe the role of modelling tools to assist with the response to the pandemic. DESIGN AND SETTING: Prospective modelling with the tools FluSurge 2.0 and FluAid 2.0 (developed by the United States Centers for Disease Control and Prevention) over 12 weeks from when the pandemic "Contain" Phase was declared on 22 May 2009, compared with data obtained from daily hospital reports of pandemic (H1N1) 2009 influenza-related admissions and transfers to intensive care units (ICUs). MAIN OUTCOME MEASURES: The effect on hospitals as projected by the FluAid 2.0 model compared with observed hospital admissions and ICU admissions. RESULTS: Prospective use of the FluAid 2.0 model provided valuable health intelligence for assessment and projection of hospitalisation and critical care demand through the first 10 weeks of the pandemic in Victoria. The observed rate of hospital admissions for pandemic (H1N1) 2009 was broadly consistent with a 5% gross clinical attack rate, with 0.3% of infected patients being hospitalised. Transfers to ICUs occurred at a rate of 20% of hospital admissions, and were associated with vulnerable patient groups, and severe respiratory failure in 82% of patients admitted to ICUs. Most patients treated in ICUs (85%) survived after an average ICU length of stay of 9 days (SD, 6.5 days). Mechanical ventilation was required by 72% of patients admitted to ICUs, and extracorporeal membrane oxygenation (ECMO) was used for 7%. Pre-existing haematological malignancy accounted for half of all the deaths in patients admitted to ICUs with pandemic (H1N1) 2009 influenza. CONCLUSIONS: Prospective use of modelling tools informed critical decisions in the planning and management of the pandemic. Early estimation of the clinical attack rate, hospitalisation rates, and demand for ICU beds guided implementation of surge capacity. ECMO emerged as an important treatment modality for pandemic (H1N1) 2009 influenza, and will be an important consideration for future pandemic planning.

Low high-density lipoprotein-cholesterol is the most prevalent metabolic abnormality for Australian Aboriginal men and women even when lean.

BACKGROUND: The aim of this study was to investigate the relationship of the prevalence and risk of the metabolic syndrome to body mass index (BMI) in Australian Aboriginal people. DESIGN: It was a cross-sectional, secondary analysis of data obtained from population-based screenings in Aboriginal communities in central and northern Australia (913 participants recruited between 1993 and 1997). RESULTS: Forty-one percent of men and 48% of women conformed to the National Cholesterol Education Program definition for the metabolic syndrome (chi2=3.72, P=0.054). The prevalence of low high-density lipoprotein-cholesterol was high in all BMI categories (89 and 95% in men and women, respectively). The prevalence of all other metabolic abnormalities increased linearly with BMI. CONCLUSION: The metabolic syndrome is highly prevalent in Aboriginal communities and is strongly associated with BMI. Low high-density lipoprotein-cholesterol was the predominant component of the metabolic syndrome across sex groups and BMI strata.

Avoidable mortality in Victoria between 1979 and 2001.

OBJECTIVE: To describe trends in avoidable mortality (AM) in Victoria by sex, degree of socio-economic disadvantage and remoteness. METHODS: The analysis is based on mortality and population data for 1979-2001 supplied by the Australian Bureau of Statistics (ABS) for Victoria. Total and disease-specific AM rates were age standardised using the direct method. For the period between 1997 and 2001, comparisons of total AM rates by sex were made between metropolitan and rural local government areas (LGAs), and between LGAs grouped into quintiles based on socio-economic disadvantage and categories of remoteness. RESULTS: Total AM rates declined significantly (p < 0.05) in both males and females between 1979 and 2001, but were significantly higher in males compared with females. Total AM rates were significantly higher in rural compared with metropolitan LGAs, from 1997 to 2001 in males and in 1998 in females. Total AM rates in the least disadvantaged quintile were significantly lower than those in the most disadvantaged quintile over the entire five-year period in males and in three years in females. Total AM rates were highest in remote LGAs and lowest in highly accessible LGAs. There were significant declines in ischaemic heart disease, stroke and road traffic accident AM rates among males. In females, IHD, stroke, breast and colon cancer AM rates declined significantly. CONCLUSIONS AND IMPLICATIONS: Despite large declines in AM in Victoria, there are significant differences in rates between the sexes and in the population based on socio-economic status or remoteness. These results provide opportunities for policy makers to prioritise public health and health services interventions, targeting population groups and specific disease conditions to reduce health inequalities.

Increased arterial stiffness in remote Indigenous Australians with high risk of cardiovascular disease.

OBJECTIVE: To assess central and peripheral arterial stiffness in Indigenous and European Australians with and without type 2 diabetes using applanation tonometry to obtain the augmentation index (AI) and pulse wave velocity (PWV). METHODS: AI was assessed in 162 Indigenous Australians (60 with type 2 diabetes) participating in a population-based study and 121 Australians of European ancestry (38 with diabetes) of similar age and sex. PWV was assessed in a subgroup: n = 62 indigenous, n = 118 European participants. RESULTS: The indigenous group had higher AI than the European group [mean (SD) 32 (12) versus 24 (12)%, P < 0.0001] and carotid-femoral PWV [8.4 (1.8) versus 7.1 (2.2) ms(-1), P < 0.0001]. There were no significant differences between groups regarding blood pressure and total cholesterol; however, indigenous individuals had higher fasting glucose, insulin, haemoglobin A1c, triglycerides, waist circumference (despite lower body mass index), and a higher prevalence of cigarette smoking. Fifty-five per cent of the variance in AI was explained on multiple regression analysis by age, sex, indigenous participant, heart rate, mean arterial pressure, height, triglycerides and waist circumference. Age, indigenous participant, heart rate, mean arterial pressure and antihypertensive medication explained 56% of the variance in PWV. Variables of the metabolic syndrome and smoking, C-reactive protein (CRP), homocysteine and heart rate clustered with indigenous status on factor analysis. CONCLUSIONS: Indigenous Australians have higher indices of peripheral and central arterial stiffness than European Australians of similar age and sex. Factor analysis revealed that metabolic syndrome variables, smoking, CRP, homocysteine and heart rate clustered with 'indigenous participant' and may explain increased arterial stiffness in this group.

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.

Central obesity is associated with reduced peripheral wave reflection in Indigenous Australians irrespective of diabetes status.

OBJECTIVE: To determine the influence of central obesity and type 2 diabetes on peripheral wave reflection in Indigenous Australians. DESIGN AND METHODS: A cross-sectional study of remote Indigenous Australians with (n = 43) and without (n = 54) type 2 diabetes of similar age (47 years) and sex; using anthropometric and bioelectrical impedance measures of obesity and applanation tonometry to determine the aortic augmentation index (AI) as an index of peripheral wave reflection. RESULTS: Indices of obesity were significantly higher in the diabetic than non-diabetic participants [body mass index (BMI): 27.3 versus 24.6 kg/m, P = 0.018; waist circumference: women 101 versus 94 cm, P = 0.008, men 102 versus 91 cm, P = 0.039]. AI was negatively related to obesity: BMI (r = -0.35, P = 0.0003), weight (r = -0.44, P < 0.0005), waist circumference (r = -0.34, P = 0.0003) and fat mass (r = -0.35, P < 0.0005). There was no significant difference in AI between the groups with and without diabetes. On multiple regression analysis, 66% of the variance in AI was explained with the following significant predictors: age, heart rate, male gender, fat mass and mean arterial pressure. Similar results were obtained when weight, waist circumference or BMI were substituted for fat mass. CONCLUSION: When compared with Indigenous Australians without diabetes, those with type 2 diabetes do not have greater aortic pressure augmentation from peripheral wave reflection. However, obesity, irrespective of the index used, was related to lower peripheral wave reflection in both those with and without type 2 diabetes.