Low serum 25-hydroxyvitamin D is associated with increased risk of the development of the metabolic syndrome at five years : results from a national, population-based prospective study (the Australian Diabetes, Obesity and Lifestyle Study : AusDiab)

Context: Serum 25-hydroxyvitamin D [25(OH)D] concentration has been inversely associated with the prevalence of metabolic syndrome (MetS), but the relationship between 25(OH)D and incident MetS remains unclear.

Objective: We evaluated the prospective association between 25(OH)D, MetS, and its components in a large population-based cohort of adults aged 25 yr or older.

Design: We used baseline (1999–2000) and 5-yr follow-up data of the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab).

Participants: Of the 11,247 adults evaluated at baseline, 6,537 returned for follow-up. We studied those without MetS at baseline and with complete data (n = 4164; mean age 50 yr; 58% women; 92% Europids).

Outcome Measures: We report the associations between baseline 25(OH)D and 5-yr MetS incidence and its components, adjusted for age, sex, ethnicity, season, latitude, smoking, family history of type 2 diabetes, physical activity, education, kidney function, waist circumference (WC), and baseline MetS components.

Results: A total of 528 incident cases (12.7%) of MetS developed over 5 yr. Compared with those in the highest quintile of 25(OH)D (≥34 ng/ml), MetS risk was significantly higher in people with 25(OH)D in the first (<18 ng/ml) and second (18–23 ng/ml) quintiles; odds ratio (95% confidence interval) = 1.41 (1.02–1.95) and 1.74 (1.28–2.37), respectively. Serum 25(OH)D was inversely associated with 5-yr WC (P < 0.001), triglycerides (P < 0.01), fasting glucose (P < 0.01), and homeostasis model assessment for insulin resistance (P < 0.001) but not with 2-h plasma glucose (P = 0.29), high-density lipoprotein cholesterol (P = 0.70), or blood pressure (P = 0.46).

Conclusions: In Australian adults, lower 25(OH)D concentrations were associated with increased MetS risk and higher WC, serum triglyceride, fasting glucose, and insulin resistance at 5 yr. Vitamin D supplementation studies are required to establish whether the link between vitamin D deficiency and MetS is causal.

Effect of pregnancy for females born small on later life metabolic disease risk

There is a strong inverse relationship between a females own birth weight and her subsequent risk for gestational diabetes with increased risk of developing diabetes later in life. We have shown that growth restricted females develop loss of glucose tolerance during late pregnancy with normal pancreatic function. 

Different patterns of Australian adults' knowledge of foods and nutrients related to metabolic disease risk

A nationwide survey of 2022 consumers was conducted in Australia in late 2011. A short list of questions about knowledge of the nutrient composition of common foods was administered along with questions about the respondents’ food attitudes, demographics, school education and dieting practices. Overall, the results showed that nutrition knowledge was relatively high. Latent class analysis showed two groups of consumers with ‘high’ and ‘low’ knowledge of nutrition. Higher knowledge was positively associated with age, female sex, university education, experience of home economics or health education at school, having a chronic disease, and attitudes to food issues, and negatively with type 1 diabetes or the use of diabetes-control diets. The implications of the findings for nutrition communication are discussed.

The metabolic syndrome and cancer: is the metabolic syndrome useful for predicting cancer risk above and beyond its individual components?

AIMS: The metabolic syndrome (MetS) is a risk factor for cancer. However, it is not known if the MetS confers a greater cancer risk than the sum of its individual components, which components drive the association, or if the MetS predicts future cancer risk. MATERIALS AND METHODS: We linked 20,648 participants from the Australian and New Zealand Diabetes and Cancer Collaboration with complete data on the MetS to national cancer registries and used Cox proportional hazards models to estimate associations of the MetS, the number of positive MetS components, and each of the five MetS components separately with the risk for overall, colorectal, prostate and breast cancer. Hazard ratios (HR) and 95% confidence intervals (95%CI) are reported. We assessed predictive ability of the MetS using Harrell's c-statistic. RESULTS: The MetS was inversely associated with prostate cancer (HR 0.85; 95% CI 0.72-0.99). We found no evidence of an association between the MetS overall, colorectal and breast cancers. For those with five positive MetS components the HR was 1.12 (1.02-1.48) and 2.07 (1.26-3.39) for overall, and colorectal cancer, respectively, compared with those with zero positive MetS components. Greater waist circumference (WC) (1.38; 1.13-1.70) and elevated blood pressure (1.29; 1.01-1.64) were associated with colorectal cancer. Elevated WC and triglycerides were (inversely) associated with prostate cancer. MetS models were only poor to moderate discriminators for all cancer outcomes. CONCLUSIONS: We show that the MetS is (inversely) associated with prostate cancer, but is not associated with overall, colorectal or breast cancer. Although, persons with five positive components of the MetS are at a 1.2 and 2.1 increased risk for overall and colorectal cancer, respectively, and these associations appear to be driven, largely, by elevated WC and BP. We also demonstrate that the MetS is only a moderate discriminator of cancer risk.

Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks in 188 countries, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013

Background: The Global Burden of Disease, Injuries, and Risk Factor study 2013 (GBD 2013) is the first of a series of annual updates of the GBD. Risk factor quantification, particularly of modifiable risk factors, can help to identify emerging threats to population health and opportunities for prevention. The GBD 2013 provides a timely opportunity to update the comparative risk assessment with new data for exposure, relative risks, and evidence on the appropriate counterfactual risk distribution. Methods: Attributable deaths, years of life lost, years lived with disability, and disability-adjusted life-years (DALYs) have been estimated for 79 risks or clusters of risks using the GBD 2010 methods. Risk-outcome pairs meeting explicit evidence criteria were assessed for 188 countries for the period 1990-2013 by age and sex using three inputs: risk exposure, relative risks, and the theoretical minimum risk exposure level (TMREL). Risks are organised into a hierarchy with blocks of behavioural, environmental and occupational, and metabolic risks at the first level of the hierarchy. The next level in the hierarchy includes nine clusters of related risks and two individual risks, with more detail provided at levels 3 and 4 of the hierarchy. Compared with GBD 2010, six new risk factors have been added: handwashing practices, occupational exposure to trichloroethylene, childhood wasting, childhood stunting, unsafe sex, and low glomerular filtration rate. For most risks, data for exposure were synthesised with a Bayesian metaregression method, DisMod-MR 2.0, or spatial-temporal Gaussian process regression. Relative risks were based on meta-regressions of published cohort and intervention studies. Attributable burden for clusters of risks and all risks combined took into account evidence on the mediation of some risks such as high body-mass index (BMI) through other risks such as high systolic blood pressure and high cholesterol. Findings: All risks combined account for 57·2% (95% uncertainty interval [UI] 55·8-58·5) of deaths and 41·6% (40·1-43·0) of DALYs. Risks quantified account for 87·9% (86·5-89·3) of cardiovascular disease DALYs, ranging to a low of 0% for neonatal disorders and neglected tropical diseases and malaria. In terms of global DALYs in 2013, six risks or clusters of risks each caused more than 5% of DALYs: dietary risks accounting for 11·3 million deaths and 241·4 million DALYs, high systolic blood pressure for 10·4 million deaths and 208·1 million DALYs, child and maternal malnutrition for 1·7 million deaths and 176·9 million DALYs, tobacco smoke for 6·1 million deaths and 143·5 million DALYs, air pollution for 5·5 million deaths and 141·5 million DALYs, and high BMI for 4·4 million deaths and 134·0 million DALYs. Risk factor patterns vary across regions and countries and with time. In sub-Saharan Africa, the leading risk factors are child and maternal malnutrition, unsafe sex, and unsafe water, sanitation, and handwashing. In women, in nearly all countries in the Americas, north Africa, and the Middle East, and in many other high-income countries, high BMI is the leading risk factor, with high systolic blood pressure as the leading risk in most of Central and Eastern Europe and south and east Asia. For men, high systolic blood pressure or tobacco use are the leading risks in nearly all high-income countries, in north Africa and the Middle East, Europe, and Asia. For men and women, unsafe sex is the leading risk in a corridor from Kenya to South Africa. Interpretation: Behavioural, environmental and occupational, and metabolic risks can explain half of global mortality and more than one-third of global DALYs providing many opportunities for prevention. Of the larger risks, the attributable burden of high BMI has increased in the past 23 years. In view of the prominence of behavioural risk factors, behavioural and social science research on interventions for these risks should be strengthened. Many prevention and primary care policy options are available now to act on key risks.

Associations of TV viewing and physical activity with the metabolic syndrome in Australian adults

Aims/hypothesis We analysed a sample of Australian adults to determine the strength of associations of TV viewing and participation in physical activity with the metabolic syndrome.

Methods This population-based cross-sectional study included 6,241 adults aged ge35 years who were free from diagnosed diabetes mellitus and self-reported ischaemic disease and were not taking lipid-lowering or antihypertensive drugs. The metabolic syndrome was defined according to the 1999 World Health Organization criteria. Participants self-reported TV viewing time and physical activity time for the previous week.

Results The adjusted odds ratio of having the metabolic syndrome was 2.07 (95% CI 1.49–2.88) in women and 1.48 (95% CI 0.95–2.31) in men who watched TV for >14 h per week compared with those who watched le7.0 h per week. Compared with those who were less active (<2.5 h per week), the odds ratio for the metabolic syndrome was 0.72 (95% CI 0.58–0.90) in men and 0.53 (95% CI 0.38–0.74) in women who were active (ge2.5 h per week). Longer TV viewing (>14 h per week) was associated with an increased risk of insulin resistance, obesity and dyslipidaemia in both men and women. A total physical activity time of ge2.5 h per week was associated with a reduced prevalence of both insulin resistance and dyslipidaemia in both sexes and reduced prevalence of both obesity and hypertension in women.

Conclusions/interpretation Increased TV viewing time was associated with an increased prevalence of the metabolic syndrome, while physical activity was associated with a reduced prevalence. Population strategies addressing the metabolic syndrome should focus on reducing sedentary behaviours such as TV viewing, as well as increasing physical activity.

Redistribution of glucose from skeletal muscle to adipose tissue during catch-up fat. A link between catch-up growth and later metabolic syndrome.

Catch-up growth, a risk factor for later obesity, type 2 diabetes, and cardiovascular diseases, is characterized by hyperinsulinemia and an accelerated rate for recovering fat mass, i.e., catch-up fat. To identify potential mechanisms in the link between hyperinsulinemia and catch-up fat during catch-up growth, we studied the in vivo action of insulin on glucose utilization in skeletal muscle and adipose tissue in a previously described rat model of weight recovery exhibiting catch-up fat caused by suppressed thermogenesis per se. To do this, we used euglycemic-hyperinsulinemic clamps associated with the labeled 2-deoxy-glucose technique. After 1 week of isocaloric refeeding, when body fat, circulating free fatty acids, or intramyocellular lipids in refed animals had not yet exceeded those of controls, insulin-stimulated glucose utilization in refed animals was lower in skeletal muscles (by 20–43%) but higher in white adipose tissues (by two- to threefold). Furthermore, fatty acid synthase activity was higher in adipose tissues from refed animals than from fed controls. These results suggest that suppressed thermogenesis for the purpose of sparing glucose for catch-up fat, via the coordinated induction of skeletal muscle insulin resistance and adipose tissue insulin hyperresponsiveness, might be a central event in the link between catch-up growth, hyperinsulinemia and risks for later metabolic syndrome.

Overweight, obesity and metabolic syndrome in rural south-eastern Australia

Aims & rationale/Objectives : To measure the prevalence of overweight, obesity and the metabolic syndrome in rural Australia.</p>

Methods :Two cross-sectional population surveys of chronic disease risk factors were carried out in rural Victoria (Corangamite Shire) and South Australia (Limestone Coast) in 2004-05. For both surveys, a stratified random sample of the population aged 25 to 74 years was drawn from the electoral roll. The surveys comprised a self-administered questionnaire, physical measurements and laboratory tests.</p>

Principal findings : A total of 841 individuals had complete questionnaire, health check and measured MetS data. The prevalence of overweight and obesity was 75% in males and 64.7% in females defined by BMI. Using waist circumference, the prevalence of overweight and obesity was higher in females (72.9%) than in males (63.2%). The overall prevalence of obesity of was 30.1% when defined by BMI, but 44.8% when defined by waist circumference. The prevalence of metabolic syndrome according to NCEP ATP III 2005 criteria was 29.0% in males and 28.5% in females. According to IDF criteria, the prevalence for males and females were 30.5% and 36.3%, respectively. The prevalence of metabolic syndrome and central (abdominal) obesity, hyperglycaemia, hypertension, and hypertriglyceridaemia increased with age.

Discussion : The prevalence of overweight and obesity, in particular central obesity, in rural Australia is very high as is the prevalence of metabolic syndrome.

Implications : Urgent population wide action is required to turn this trend around and regular monitoring of the trends in response to such action is essential.

A culturally appropriate diet and lifestyle intervention can successfully treat the components of metabolic syndrome in female Pakistani immigrants residing in Melbourne, Australia

This study was designed to test the effectiveness of a culturally appropriate diet and lifestyle intervention to treat metabolic syndrome in female Pakistani immigrants residing in Melbourne, Australia. Forty Pakistani women with metabolic syndrome (aged 20-50 years) completed a 12-week culturally appropriate diet and exercise program. Results indicate that, before intervention, participants were sedentary, taking 4000 ± 22.6 steps per day, and had an obese-classified body mass index (BMI) of 29.2 ± 0.46 kg/m2 (BMI was categorized in accordance with guidelines specifically designed for Asians) and high waist circumference of 132 ± 25.95 cm. Participants were hypertensive (systolic, 135 ± 1.3 mm Hg; diastolic, 86 ± 0.68 mm Hg), were dyslipidemic (total cholesterol, 6.8 ± 0.15 mmol/L; triglycerides, 2.9 ± 0.09 mmol/L), and had elevated blood glucose (6.4 ± 0.33 mmol/L) and fasting blood insulin (45 ± 6.3 μU/mL) levels. After the 12-week culturally appropriate intervention, activity increased (8600 ± 596.7 steps per day, P < .05); and BMI (27.8 ± 0.45 kg/m2), blood pressure (systolic, 125 ± 1.4 mm Hg; diastolic, 80 ± 0.6 mm Hg), cholesterol (5.5 ± 0.1 mmol/L), blood glucose (5.9 ± 0.33 mmol/L), and blood insulin (24.14 ± 1.8 μU/mL) levels were all significantly reduced (P < .05). This study revealed that the Pakistani female migrants who had metabolic syndrome and its components can successfully be treated via a culturally appropriate diet and lifestyle intervention. The success of the current program raises the possibility that other high-risk ethnic groups can also be treated with a culturally appropriate program.

The metabolic syndrome: in need of a global mission statement

Aims The value of clinical definitions of the metabolic syndrome has been questioned, with confusion surrounding their intended use and purpose. Our aim was to construct a mission statement that outlines the value of the metabolic syndrome in clinical and public health settings.

Methods Case studies have been used to demonstrate three key points.

Results We argue here for recognition of obesity as being a crucial element within the metabolic syndrome but perhaps even more important before its development. We also contend that the concept does indeed have a role as a risk prediction tool, and that it could provide a useful metric for the scale and progress of the looming global epidemic of diabetes and cardiovascular disease.

Conclusions Through appreciation of its purpose, and recognition of both its limitations and those attributes that make it unique and valuable, we believe we have demonstrated here that the metabolic syndrome deserves its place in the global toolbox of diabetes and CVD prevention.

The metabolic syndrome as a tool for predicting future diabetes : the AusDiab study

Objective. To compare the ability of the metabolic syndrome (MetS), a diabetes prediction model (DPM), a noninvasive risk questionnaire and individual glucose measurements to predict future diabetes.

Design. Five-year longitudinal cohort study. Tools tested included MetS definitions [World Health Organization, International Diabetes Federation, ATPIII and European Group for the study of Insulin Resistance (EGIR)], the FINnish Diabetes RIsk SCore risk questionnaire, the DPM, fasting and 2-h post load plasma glucose.

Setting. Adult Australian population.

Subjects. A total of 5842 men and women without diabetes ≥25 years. Response 58%. A total of 224 incident cases of diabetes.

Results. In receiver operating characteristic curve analysis, the MetS was not a better predictor of incident diabetes than the DPM or measurement of glucose. The risk for diabetes among those with prediabetes but not MetS was almost triple that of those with MetS but not prediabetes (9.0% vs. 3.4%). Adjusted for component parts, the MetS was not a significant predictor of incident diabetes, except for EGIR in men [OR 2.1 (95% CI 1.2–3.7)].

Conclusions. A single fasting glucose measurement may be more effective and efficient than published definitions of the MetS or other risk constructs in predicting incident diabetes. Diagnosis of the MetS did not confer increased risk for incident diabetes independent of its individual components, with an exception for EGIR in men. Given these results, debate surrounding the public health utility of a MetS diagnosis, at least for identification of incident diabetes, is required.

The metabolic syndrome as a predictor of incident diabetes mellitus in Mauritius

Aims : To assess the utility of the metabolic syndrome (MetS) and a Diabetes Predicting Model as predictors of incident diabetes.

Methods : A longitudinal survey was conducted in Mauritius in 1987 (n = 4972; response 80%) and 1992 (n = 3685; follow-up 74.2%). Diabetes status was retrospectively determined using 1999 World Health Organization (WHO) criteria. MetS was determined according to four definitions and sensitivity, positive predictive value (PPV), specificity and the association with incident diabetes before and after adjustment for MetS components calculated.

Results : Of the 3198 at risk, 297 (9.2%) developed diabetes between 1987 and 1992. The WHO MetS definition had the highest prevalence (20.3%), sensitivity (42.1%) and PPV (26.8%) for prediction of incident diabetes, the strongest association with incident diabetes after adjustment for age and sex [odds ratio 4.6 (3.5–6.0)] and was the only definition to show a significant association after adjustment for its component parts (in men only). The low prevalence and sensitivity of the International Diabetes Federation (IDF) and ATPIII MetS definitions resulted from waist circumference cut-points that were high for this population, particularly in men, and both were not superior to a diabetes predicting model on receiver operating characteristic analysis.

Conclusions : Of the MetS definitions tested, the WHO definition best identifies those who go on to develop diabetes, but is not often used in clinical practice. If cut-points or measures of obesity appropriate for this population were used, the IDF and ATPIII MetS definitions could be recommended as useful tools for prediction of diabetes, given their relative simplicity.

The metabolic syndrome in Australia : prevalence using four definitions

Objective : To compare the prevalence of the Metabolic Syndrome (MetS) defined by four definitions and to determine which definition best identifies those at high cardiovascular disease (CVD) risk and with insulin resistance.

Methods : AusDiab is a population-based survey of 11,247 Australians. Participants had anthropometry, blood pressure, and fasting biochemistry. Ten-year CVD risk was calculated.

Results : The prevalence of the MetS using the ATPIII, WHO, IDF, and EGIR definitions was 22.1% (95%Cl: 18.8, 25.4), 21.7% (19.0, 24.3), 30.7% (27.1, 34.3), and 13.4% (11.8, 14.9), respectively. Comparing those with to those without the MetS, the odds ratios (95%CI) for having a 10 year CVD risk ≥15% were 6.6 (5.4, 8.2), 5.5 (4.7, 6.5), 5.6 (4.8, 6.6), and 3.5 (3.0, 4.1), for the WHO, ATPIII, IDF, and EGIR definitions, respectively. The population attributable risk (PAR) of high CVD risk due to the MetS was highest for the IDF (23.4%). Insulin resistance was detected in 56.1, 69.7, 50.9, and 91.1% of those meeting the ATPIII, WHO, IDF, and EGIR definitions, respectively.

Conclusion : The WHO definition was associated with the greatest CVD risk, but is not practical for clinical use. The higher PAR due to the IDF definition, with only slightly lower CVD risk than WHO, and clinical utility of the IDF definition, indicates that it may be a useful tool for CVD prevention.

HOMA insulin sensitivity index and the risk of all-cause mortality and cardiovascular disease events in the general population : the Australian diabetes, obesity and lifestyle study (AusDiab) study

Aims/hypothesis We assessed whether the relationships between insulin sensitivity and all-cause mortality as well as fatal or non-fatal cardiovascular disease (CVD) events are independent of elevated blood glucose, high blood pressure, dyslipidaemia and body composition in individuals without diagnosed diabetes.
Methods Between 1999 and 2000, baseline fasting insulin, glucose and lipids, 2 h plasma glucose, HbA1c, anthropometrics, blood pressure, medication use, smoking and history of CVD were collected from 8,533 adults aged >35 years from the population-based Australian Diabetes, Obesity and Lifestyle study. Insulin sensitivity was estimated by HOMA of insulin sensitivity (HOMA-%S). Deaths and fatal or non-fatal CVD events were ascertained through linkage to the National Death Index and medical records adjudication.
Results After a median of 5.0 years there were 277 deaths and 225 CVD events. HOMA-%S was not associated with all-cause mortality. Compared with the most insulin-sensitive quintile, the combined fatal or non-fatal CVD HR (95% CI) for quintiles of decreasing HOMA-%S were 1.1 (0.6–1.9), 1.4 (0.9–2.3), 1.6 (1.0–2.5) and 2.0 (1.3–3.1), adjusting for age and sex. Smoking, CVD history, hypertension, lipid-lowering medication, total cholesterol and waist-to-hip ratio moderately attenuated this relationship. However, the association was rendered non-significant by adding HDL. Fasting plasma glucose, but not HOMA-%S significantly improved the prediction of CVD, beyond that seen with other risk factors.
Conclusions/interpretation In this cohort, HOMA-%S showed no association with all-cause mortality and only a modest association with CVD events, largely explained by its association with HDL. Fasting plasma glucose was a better predictor of CVD than HOMA-%S.