Lifestyle interventions reduce the incidence of type 2 diabetes among individuals with impaired glucose tolerance (IGT). However, it is unknown whether this is due to improved insulin sensitivity or insulin secretion. We investigated at baseline insulin sensitivity and insulin secretion applying frequently sampled intravenous glucose tolerance test (FSIGT) in 87 of 101 obese middleaged subjects with IGT randomized into an intervention or a control group in the Finnish Diabetes Prevention Study. FSIGT was repeated after 4 years in 52 people. There were no significant differences in any of the baseline anthropometric or metabolic characteristics between the groups. The 4-year weight and waist circumference decreases were greater in the intervention than in the control group (P ‫؍‬ 0.043 and P ‫؍‬ 0.025, respectively). At 4-year examination, insulin sensitivity (S i ) tended to be higher in the intervention group (the difference between the mean values 36%; P ‫؍‬ 0.067, and P ‫؍‬ 0.136 after adjustment for age, sex, BMI, and baseline S i value). There was strong correlation between the 4-year changes in S i and weight (r ‫؍‬ ؊0.628 and r ‫؍‬ ؊0.710, for intervention and control groups; P < 0.001 for both). In the entire group, S i improved by 64% in the highest tertile of weight loss but deteriorated by 24% in those who gained weight (lowest tertile). Acute insulin response declined significantly in the control group. In conclusion, S i markedly improved by weight reduction during the 4-year follow-up of individuals with IGT. Insulin secretion remained constant for years in individuals with IGT who were able to lose weight.

Objective: Lifestyle and genetic factors interact in the development of obesity and the metabolic syndrome. The molecular mechanisms underlying the beneficial dietary modifications are, however, unclear. We aimed to examine the effect of the longterm moderate weight reduction on gene expression in adipose tissue (AT) and to identify genes and gene clusters responsive to treatment and thereby likely contributing to the development of the metabolic syndrome. Design: Randomized controlled and individualized weight reduction intervention. Subjects: Forty-six subjects with impaired fasting glycemia or impaired glucose tolerance and features of metabolic syndrome, aged 6077 years were randomized either to a weight reduction (WR) (n ¼ 28) or a control (n ¼ 18) group lasting for 33 weeks. Measurements: Oral and intravenous glucose tolerance tests and subcutaneous AT biopsies were performed before and after the intervention. Gene expression of AT was studied using microarray technology in subgroups of WR (with weight reduction X5%, n ¼ 9) and control group (n ¼ 10). The results were confirmed using quantitative PCR. Results: In the WR group, glucose metabolism improved. Moreover, an inverse correlation between the change in S I and the change in body weight was found (r ¼ À0.44, P ¼ 0.026). Downregulation of gene expression (Po0.01) involving gene ontology groups of extracellular matrix and cell death was seen. Such changes did not occur in the control group. The tenomodulin-gene was one of the most downregulated genes (À39716%, Po0.0001). Moreover, its expression correlated with insulin sensitivity (r ¼ À0.34, P ¼ 0.005) before the intervention and with body adiposity both before (r ¼ 0.42, P ¼ 0.007) and after (r ¼ 0.30, P ¼ 0.056) the intervention. Conclusion: Genes regulating the extracellular matrix and cell death showed a strong downregulation after long-term weight reduction. This likely reflects a new stable state at the molecular level in AT. Further studies are warranted to elucidate the mechanisms of these genetic factors.

Dietary carbohydrate modification with rye and pasta or oat, wheat, and potato differentially modulates the gene expression profile in abdominal subcutaneous adipose tissue, even in the absence of weight loss.

OBJECTIVE: Genetic variation in leptin receptor (LEPR) gene has been reported to associate with insulin and glucose metabolism and adiposity in different study settings and various populations. We wanted to evaluate the association between LEPR polymorphisms, diabetes risk and body weight in Finnish subjects with impaired glucose tolerance (IGT). METHODS: We investigated the associations of the three LEPR polymorphisms (Lys109Arg, Gln223Arg, 3 0 UTR Del/Ins) with the conversion to type 2 diabetes and the changes in body weight in 507 individuals with IGT participating in the Finnish Diabetes Prevention Study. Participants were randomized to either an intensive diet and exercise intervention group or a control group. RESULTS: After 3 years, the odds ratio for the development of type 2 diabetes in individuals in the control group with the Lys109Lys genotype was 2.38-fold higher than in individuals with other genotype combinations (P ¼ 0.016). Irrespective of group individuals with the Gln223Gln genotype had higher conversion to type 2 diabetes (OR 2.01 (95% CI 1.03-3.93)) than the Arg223 allele carriers (P ¼ 0.042). The risk was more pronounced in the control group than in the intervention group. Individuals having the 3 0 UTR Del/Del genotype had a slightly higher body weight throughout the study than those with the insertion allele (P ¼ 0.020), although no difference in weight change was observed. CONCLUSION: Two polymorphisms (Lys109Arg, Gln223Arg) in the extracellular domain of the leptin receptor predicted the conversion to type 2 diabetes in high-risk individuals with IGT. The Del/Ins polymorphism in the 3 0 UTR of LEPR was associated with body weight.

Background: We explored the associations of three variants in the uncoupling protein 2 (UCP2) gene, one variant in the UCP2-UCP3 intergenic region and five variants in the uncoupling protein 3 (UCP3) gene with obesity and diabetes related traits in subjects with impaired glucose tolerance participating in Finnish Diabetes Prevention Study. Altogether 507 overweight individuals (body mass index: 31.2 ± 4.5 kg/m 2 , age: 55 ± 7 years) for whom DNA was available were randomized to either an intensified diet and physical activity group or to a conventional care control group.