Objective: The metabolic syndrome (MS) is a cluster of cardiometabolic factors, which predisposes to diabetes and cardiovascular disease (CVD). Early detection of high-risk individuals for MS using accurate measures of insulin resistance (IR) could improve detection and prevention of CVD and diabetes. The aim of this study was to explore the ability of lipid accumulation product (LAP), compared with traditional measures of IR, to identify MS. Design: In total, 768 Spanish adults were recruited. MS was assessed using the revised criteria of National Cholesterol Education Program/Adult Treatment Panel III (NCEP/ATP III) and International Diabetes Federation (IDF). Measures of IR such as homeostasis model assessment of IR and LAP, an index of lipid accumulation based on a combination of waist circumference and serum triglycerides, were calculated. Receiver operating characteristic analysis was performed in order to detect the parameter with the best predictive capability for MS. Results: The prevalence of MS-NCEP/ATP III and MS-IDF was 15.1 and 20.5% for men respectively, and 15.4 and 17.5% for women. LAP showed the highest diagnostic accuracy for MS-NCEP/ATP III (area under the curve 0.91 and 0.90 among males and females) and MS-IDF (0.88 for both males and females). This was confirmed by internal validation using 20 000 bootstrap samples. Among males and females, different LAP cut-off values exhibited high sensitivity (78-85%) and specificity (78-85%) for MS-NCEP/ATP III and MS-IDF identification with elevated efficiency (proportion of positives and negatives classified correctly by the testZ78-85%). When the sample was stratified according to decades of life, LAP exhibited a slightly lower performance among women than men, especially for MS-IDF detection. Conclusions: In non-diabetic adults LAP has a strong and reliable diagnostic accuracy for MS-IDF and, especially, MS-NCEP/ATP III among females and, in particular, among males from Spain.

The study was designed to evaluate the chronic regulation of plasma leptin by dietary (n-3) polyunsaturated fatty acids (PUFA) in insulin-resistant, sucrose-fed rats. Male Sprague-Dawley rats were randomly assigned to consume for 3 or 6 wk a diet containing 57.5% (g/100 g) sucrose and 14% lipids as either fish oil (SF) or control oils (SC). After 3 and 6 wk of consuming the SF diet, plasma leptin was 70% (P < 0.001) and 75% (P < 0.05) greater, respectively, than in rats fed the SC diet. The same result was found when plasma leptin was adjusted by total fat mass, as measured by dual-energy X-ray absorptiometry. Despite high leptin levels, food intake of rats fed the SF diet was greater than in SC-fed rats without any difference in body weight or total fat mass. After 3 wk, accumulated leptin in epididymal and retroperitoneal adipose tissue was higher in the SF-fed rats than in the SC-fed rats. However, after 6 wk, tissue leptin in the SF-fed rats did not differ from that of the SC-fed rats. The SF diet increased adipose tissue glucose transporter-4 protein quantity and prevented the sucrose-induced elevations in plasma triglycerides and free fatty acids. When all SC- and SF-fed rats (both diets and feeding durations) were considered, plasma leptin levels were positively correlated with body weight (r = 0.5, P < 0.0001) and with total fat mass (r = 0.5, P < 0.0005). These results suggest that plasma leptin at a given time could be inappropriately high for a given fat mass in insulin-sensitive rats fed (n-3) PUFA.

In conclusion, we observed, in a cohort of Caucasians with C-peptide-negative type 1 diabetes, a novel association between the functional FokI VDR polymorphism and severe DR, especially among subjects with fewer than 25 yr of diabetes duration.