OBJECTIVES: To examine the association between the content of n-3 fatty acids and insulin resistance in an Inuit population. STUDY DESIGN: The Inuit Health in Transition Study was carried out between 2003 and 2007 in Greenland as a cross-sectional study. Our preliminary results are based on the first 452 participants aged 18 and above. Only participants with at least 1 Inuit grandparent and without diabetes were included. METHODS: The contents of n-3 fatty acids and the n-3/n-6 ratio were measured in the erythrocyte membrane phospholipids. BMI was calculated and questions concerning diabetes and ethnicity were answered. Insulin resistance was estimated using the HOMA-IR index based on fasting-glucose and fasting-insulin. RESULTS: We found an inverse association between C20:5 n-3 (EPA), C22:3 n-3, the n-3/n-6 ratio and HOMA-IR and a positive association between C18:3 n-3 cis and HOMA-IR. When adjusted for age, gender, BMI and ethnicity, the association remained statistically significant for C20:5 n-3 (EPA), C22:3 n-3 and C18:3 n-3 cis. CONCLUSIONS: Our findings suggest that some types of n-3 fatty acids may have a protective effect against insulin resistance. The role of potential confounders such as physical activity, diet, energy intake, socio-economic status and contaminants deserves further exploration.
OBJECTIVE: The purpose of this study was to estimate the progression rates to impaired glucose regulation (impaired fasting glucose or impaired glucose tolerance) and diabetes in the Danish population-based Inter99 study and in a high-risk subpopulation, separately. RESEARCH DESIGN AND METHODS: From a population-based primary prevention study, the Inter99 study, 4,615 individuals without diabetes at baseline and with relevant follow-up data were divided into a low- and a high-risk group based on a risk estimate of ischemic heart disease or the presence of risk factors (smoking, hypertension, hypercholesterolemia, obesity, or impaired glucose tolerance). High-risk individuals (57.1%) were examined with an oral glucose tolerance test at 1 and 3 years, and all of the participants were reexamined at the 5-year follow-up. Person-years at risk were calculated. Progression rates to impaired glucose regulation and diabetes were estimated directly from baseline to the 5-year follow-up for all the participants and from baseline through the 1- and 3- to 5-year follow-up examinations for the high-risk individuals, separately. RESULTS: In the combined low- and high-risk group, 2.1 individuals per 100 person-years progressed from normal glucose tolerance (NGT) to impaired glucose regulation or diabetes. Among high-risk individuals, 5.8 per 100 person-years with NGT progressed to impaired glucose regulation or diabetes, and 4.9 per 100 person-years progressed from impaired glucose regulation to diabetes. CONCLUSIONS: Progression rates to impaired glucose regulation using the current World Health Organization classification criteria were calculated for the first time in a large European population-based study. The progression rates to diabetes show the same pattern as seen in the few similar European studies.