The relationship between lipid metabolism with prediabetes (impaired fasting glucose and impaired glucose tolerance) and type 2 diabetes mellitus is poorly defined. We hypothesized that a lipidomic analysis of plasma lipids might improve the understanding of this relationship. We performed lipidomic analysis measuring 259 individual lipid species, including sphingolipids, phospholipids, glycerolipids and cholesterol esters, on fasting plasma from 117 type 2 diabetes, 64 prediabetes and 170 normal glucose tolerant participants in the Australian Diabetes, Obesity and Lifestyle Study (AusDiab) then validated our findings on 1076 individuals from the San Antonio Family Heart Study (SAFHS). Logistic regression analysis of identified associations with type 2 diabetes (135 lipids) and prediabetes (134 lipids), after adjusting for multiple covariates. In addition to the expected associations with diacylglycerol, triacylglycerol and cholesterol esters, type 2 diabetes and prediabetes were positively associated with ceramide, and its precursor dihydroceramide, along with phosphatidylethanolamine, phosphatidylglycerol and phosphatidylinositol. Significant negative associations were observed with the ether-linked phospholipids alkylphosphatidylcholine and alkenylphosphatidylcholine. Most of the significant associations in the AusDiab cohort (90%) were subsequently validated in the SAFHS cohort. The aberration of the plasma lipidome associated with type 2 diabetes is clearly present in prediabetes, prior to the onset of type 2 diabetes. Lipid classes and species associated with type 2 diabetes provide support for a number of existing paradigms of dyslipidemia and suggest new avenues of investigation.

OBJECTIVETo examine whether serum 25-hydroxyvitamin D (25OHD) and dietary calcium predict incident type 2 diabetes and insulin sensitivity.RESEARCH DESIGN AND METHODSA total of 6,537 of the 11,247 adults evaluated in 1999–2000 in the Australian Diabetes, Obesity and Lifestyle (AusDiab) study, returned for oral glucose tolerance test (OGTT) in 2004–2005. We studied those without diabetes who had complete data at baseline (n = 5,200; mean age 51 years; 55% were women; 92% were Europids). Serum 25OHD and energy-adjusted calcium intake (food frequency questionnaire) were assessed at baseline. Logistic regression was used to evaluate associations between serum 25OHD and dietary calcium on 5-year incidence of diabetes (diagnosed by OGTT) and insulin sensitivity (homeostasis model assessment of insulin sensitivity [HOMA-S]), adjusted for multiple potential confounders, including fasting plasma glucose (FPG).RESULTSDuring the 5-year follow-up, 199 incident cases of diabetes were diagnosed. Those who developed diabetes had lower serum 25OHD (mean 58 vs. 65 nmol/L; P < 0.001) and calcium intake (mean 881 vs. 923 mg/day; P = 0.03) compared with those who remained free of diabetes. Each 25 nmol/L increment in serum 25OHD was associated with a 24% reduced risk of diabetes (odds ratio 0.76 [95% CI 0.63–0.92]) after adjusting for age, waist circumference, ethnicity, season, latitude, smoking, physical activity, family history of diabetes, dietary magnesium, hypertension, serum triglycerides, and FPG. Dietary calcium intake was not associated with reduced diabetes risk. Only serum 25OHD was positively and independently associated with HOMA-S at 5 years.CONCLUSIONSHigher serum 25OHD levels, but not higher dietary calcium, were associated with a significantly reduced risk of diabetes in Australian adult men and women.

Objective: Several studies have suggested that dairy food may reduce the risk of obesity and metabolic abnormalities but few have been able to conclusively demonstrate that it reduces the risk of diabetes. The aim of the present analysis was to investigate if dairy food intake independently reduces the risk of diabetes. Design: The Australian Diabetes Obesity and Lifestyle Study (AusDiab) is a national, population-based, prospective survey conducted over 5 years. Baseline measurements included a 121-item FFQ, anthropometrics and an oral glucose tolerance test. Setting: Forty-two randomly selected clusters across Australia. Subjects: Adults aged $25 years who participated in the baseline survey and returned to follow-up 5 years later. Results: A total of 5582 participants with complete data were eligible for analysis, 209 of whom had incident diabetes. Compared with men in the first tertile of dairy food intake, men in the third tertile had a significantly reduced risk of developing diabetes after adjustment for age, sex, total energy intake, family history of diabetes, education, physical activity, smoking status, fasting serum TAG and HDL cholesterol, systolic blood pressure, waist circumference and hip circumference (OR 5 0?53, 95 % CI 0?29, 0?96; P 5 0?033). A similar non-significant association was observed in women. Conclusions: Dietary patterns that incorporate high intakes of dairy food may reduce the risk of diabetes among men. Further investigation into the relationship between dairy food intake and diabetes needs to be undertaken to fully understand the potential mechanism of this observation.

Resting heart rate is associated with an increased risk of diabetes over a 5-year period, particularly among non-obese men. This suggests that sympathetic overactivity may be a contributing factor to the development of diabetes, and that resting heart rate may be useful in predicting risk of Type 2 diabetes in non-obese men.

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