Patterns of insulin resistance in the general population of southeast Spain

Morbid Obesity in Women Is Associated with an Altered Intestinal Expression of Genes Related to Cancer Risk and Immune, Defensive, and Antimicrobial Response

Background: Little is known about the relation between morbid obesity and duodenal transcriptomic changes. We aimed to identify intestinal genes that may be associated with the development of obesity regardless of the degree of insulin resistance (IR) of patients. Material and Methods: Duodenal samples were assessed by microarray in three groups of women: non-obese women and women with morbid obesity with low and high IR. Results: We identified differentially expressed genes (DEGs) associated with morbid obesity, regardless of IR degree, related to digestion and lipid metabolism, defense response and inflammatory processes, maintenance of the gastrointestinal epithelium, wound healing and homeostasis, and the development of gastrointestinal cancer. However, other DEGs depended on the IR degree. We mainly found an upregulation of genes involved in the response to external organisms, hypoxia, and wound healing functions in women with morbid obesity and low IR. Conclusions: Regardless of the degree of IR, morbid obesity is associated with an altered expression of genes related to intestinal defenses, antimicrobial and immune responses, and gastrointestinal cancer. Our data also suggest a deficient duodenal immune and antimicrobial response in women with high IR.

Cumulative inflammatory burden and obesity as determinants of insulin resistance in patients with established rheumatoid arthritis: cross-sectional study

OBJECTIVES

To describe the prevalence of insulin resistance (IR) in patients with established rheumatoid arthritis (RA) and to analyse the contribution of cumulative inflammatory burden and other factors to its development.

DESIGN

Observational cross-sectional study.

PARTICIPANTS

Patients with RA and controls matched for age, sex and Body Mass Index. We excluded patients with diabetes.

SETTINGS

Patients from an RA inception cohort at Hospital Regional Universitario de Málaga, Spain, were recruited between September 2016 and May 2018.

PRIMARY AND SECONDARY OUTCOME MEASURES

IR was evaluated using the homeostasis model assessment for IR and beta-cell function and the quantitative insulin sensitivity check index. Other variables included the cumulative 28-Joint Disease Activity Score (DAS28) with C reactive protein (CRP) body composition and cytokines. Two logistic regression models were constructed to identify factors associated with IR in patients with RA.

RESULTS

Eighty-nine patients with RA and 80 controls were included. The prevalence of IR was similar in both cases and controls. Inflammatory activity was controlled appropriately in patients during follow-up (mean DAS28 3.1 (0.8)). The presence of IR in patients with RA was associated with obesity (OR 6.01, 95% CI 1.9 to 8.7), higher cumulative DAS28-CRP values during follow-up (OR 2.8, 95% CI 1.3 to 6.0), and higher interleukin-1β levels (OR 1.6, 95% CI 1.1 to 2.4). The second model showed that the risk of IR increased by 10% for each kilogram of excess body fat.

CONCLUSION

In patients with well-controlled, established RA, IR is associated mainly with poorer control of inflammation from diagnosis and with obesity, specifically total fat mass.

Different Expression of Duodenal Genes Related to Insulin Resistance Between Nonobese Women and Those with Severe Obesity

OBJECTIVE

The study aim was to identify changes in duodenal gene expression associated with the development of insulin resistance according to the BMI of women.

METHODS

Duodenal samples were assessed by microarray in four groups of women, nonobese women and women with severe obesity, with both low and high insulin resistance.

RESULTS

There was a group of shared downregulated differentially expressed genes (DEGs) related to tissue homeostasis and antimicrobial humoral response in women with higher insulin resistance both with severe obesity and without obesity. In the exclusive DEGs found in severe obesity, downregulated DEGs related to the regulation of the defense response to bacterium and cell adhesion, involving pathways related to the immune system, inflammation, and xenobiotic metabolism, were observed. In the exclusive DEGs from nonobese women with higher insulin resistance, upregulated DEGs mainly related to the regulation of lipoprotein lipase activity, very low-density lipoprotein particle remodeling, lipid metabolic process, antigen processing, and the presentation of peptide antigen were found.

CONCLUSIONS

Independent of BMI, higher insulin resistance was associated with a downregulation of duodenal DEGs mainly related to the immune system, inflammation, and xenobiotic metabolism. Also, intestinal lipoprotein metabolism may have a certain relevance in the regulation of insulin resistance in nonobese women.

Transcriptional Analysis of FOXO1, C/EBP-α and PPAR-γ2 Genes and Their Association with Obesity-Related Insulin Resistance

BACKGROUND

Obesity is associated with several comorbid disorders, ranging from cardiovascular diseases to insulin resistance. In this context, visceral adipose tissue (VAT) seems to have a close connection with insulin resistance. In our study, we hypothesized that the expression profile of key adipogenic genes, such as proliferator-activated receptor γ type 2 (PPAR-γ2), CCAAT/enhancer-binding protein type α (C/EBP-α), and forkhead box protein class O type 1 (FOXO1) in VAT should shed light on their association with obesity-related insulin resistance.

METHODS

To test this idea, we studied the expression profile of C/EBP-α, FOXO1 and PPAR-γ2 in VAT from non-obese individuals, and low insulin (LIR-MO) and high insulin morbidly obese (HIR-MO) subjects, through a combination of RT-qPCR, co-immunoprecipitation, ELISA, Western blot analysis and EMSA assays.

RESULTS

Our results show that C/EBP-α and PPAR-γ2 were down-expressed in HIR-MO individuals, while FOXO1 was overexpressed. In addition, the PPAR-γ2-RXR-α heterodimer showed weak activity and bound weakly to the putative IGFBP-2-PPRE promoter sequence in VAT from HIR-MO subjects when compared with LIR-MO individuals.

CONCLUSIONS

These results show that PPAR-γ2, C/EBP-α, FOXO1 and IGFBP-2 have a close relationship with insulin resistance in VAT of morbidly obese individuals.

Carbohydrate status in patients with phenylketonuria

BACKGROUND

In patients with phenylketonuria (PKU), a low-phenylalanine (Phe) diet supplemented with low-protein foods and a Phe-free amino acid mixture favors a dietary intake rich in carbohydrates, but little is known about how these molecules are metabolized in this setting. The objective of the present study was to analyze carbohydrate metabolism in patients with hyperphenylalaninemia.

METHODS

We conducted a multicenter cross-sectional study to investigate biochemical markers of basal and postprandial carbohydrate metabolism in PKU patients according to age, Phe tolerance, waist circumference and body mass index (BMI), diet, tetrahydrobiopterin (BH4) supplementation, and adherence to treatment. Basal biomarkers and anthropometric parameters were also evaluated in patients with mild hyperphenylalaninemia (MHPA) and in healthy controls.

RESULTS

A total of 83 patients aged 4-52 years were studied; 68.7% had PKU and 31.3% had MHPA. 68 healthy controls of similar sex and age were also evaluated Metabolic control was adequate in 71.9% of PKU patients. Fasting glucose levels (mean 80.77 ± 8.06 mg/dL) were high in just one patient, but fasting insulin levels, with a mean of 12.74 ± 8.4 mIU/L, were altered in 15 PKU patients (26.3%) and markedly higher than in patients with MPHA (p = 0.035). Fasting insulin levels and Homeostasis Model Assessment Insulin Resistance (HOMA-IR) were significantly higher than in healthy controls and correlated with body mass index, waist circumference, age, and also showed statistically significant differences according to diagnosis and Phe tolerance (p < 0.05). Patients under BH4 therapy had lower insulin levels and HOMA-IR. A higher mean carbohydrate intake from AA mixtures was observed in classic PKU patients. The caloric intake in the form of carbohydrates was also higher in PKU than MHPA patients (p = 0.038) and it was correlated with basal insulin (rho = 0.468, p = 0.006), HOMA-IR (rho = 0.423, p = 0.02), BMI (rho 0.533, p = 0.002), and waist circumference (rho 0.584, p = 0.0007).

CONCLUSIONS

This study shows that PKU patients are at risk of carbohydrate intolerance and insulin resistance, more evident in adults and overweight patients, probably related to their higher caloric intake in form carbohydrate content. A higher dependency of AA mixtures was demonstrated in PKU patients.

Modifications of the homeostasis model assessment of insulin resistance index with age

The aim of the study was to analyze the association between aging and insulin resistance estimated by the homeostasis model assessment of insulin resistance (HOMA-IR). This work involved two studies: (1) the Di@bet.es study is a cross-sectional study including 4,948 subjects, comprising a representative sample of the adult Spanish population; (2) the Pizarra study is a population-based cohort study undertaken in Pizarra (Spain), in which 1,051 subjects were evaluated at baseline and 714 completed the 6-year follow-up study. Study variables included a clinical and demographic structured survey, a lifestyle survey, a physical examination, and an oral glucose tolerance test in subjects without diabetes. In the Di@bet.es study overall, an increase occurred in blood glucose until the age of 50, after which it remained stable (data adjusted for gender, body mass index, abnormal glucose regulation [AGR]). The HOMA-IR increased significantly with age (p = 0.01), due to a higher prevalence of obesity (p < 0.0001) and AGR (p < 0.001). In non-obese subjects without AGR, HOMA-IR values were not modified with age (p = 0.30), but they were with body mass index (p < 0.001). In the Pizarra study, the HOMA-IR was significantly lower after 6-year follow-up in the whole study population. Subjects with a HOMA-IR level higher than the 75th percentile at baseline were more likely to develop diabetes (OR 2.2, 95 % CI 1.2-3.9; p = 0.007) than subjects with a lower HOMA-IR. We concluded that age per se did not increase HOMA-IR levels, changes that might be related to higher rates of obesity and AGR in older subjects. The HOMA-IR was associated with an increased risk of developing type 2 diabetes 6 years later.

The prevalence of thyroid nodules and its relationship with metabolic parameters in a Chinese community-based population aged over 40 years

To investigate the prevalence of thyroid nodules (TN) among a community population aged >40 years and to explore the association between TN and its metabolic risk factors. Data from 9,533 adults aged over 40 years who participated in the epidemiological investigation of thyroid nodules in a Chinese community-based population from June to December 2011 were included in the analyses. We compared the levels of metabolic indices between the TN group and healthy controls. The prevalence of TN was 46.6% (39.7%, men; 50.3%, women) and it increased significantly with increasing age (P < 0.001). It was significantly higher in the group with hypertension than in that with normotension (P < 0.001) and was 43.0% in the normal blood glucose group, 49.4% in the prediabetes group, and 50.9% in the diabetes group (P < 0.001). Logistic regression analysis indicated that hypertension [odds ratio (OR) = 1.121 (1.025-1.225)] as well as prediabetes and diabetes [OR = 1.130 (1.036-1.233)] were all independent risk factors for TN after adjustment for sex, age, body mass index, blood lipid levels, smoking status, and alcohol consumption. The elderly population had a high prevalence of TN. Hypertension as well as prediabetes and diabetes might be independent risk factors for TN.

Polymorphisms in the SCD1 gene are associated with indices of stearoyl CoA desaturase activity and obesity: a prospective study

SCOPE

The serum fatty acid (FA) composition is influenced by dietary fat and the endogenous production of FAs. Stearoyl CoA desaturase 1 (SCD1) is the rate-limiting enzyme catalyzing the synthesis of MUFAs from saturated FAs. Variations in SCD1 activity have been associated with obesity, diabetes, or inflammation. We evaluated the associations between genetic variation of the SCD1 gene, SCD1 activity, intake of oil, and obesity in a population-based prospective study in southern Spain.

METHODS AND RESULTS

We collected phenotypic, metabolic, nutritional, and genetic information. The type of dietary fat was assessed from samples of cooking oil taken from the participants' kitchens and analyzed by GC. A total of nine single nucleotide polymorphisms (SNPs) of the SCD1 gene were analyzed by SNPlex technology. We found a significant association between SCD1 genetic variation and enzyme activity in four of nine polymorphisms studied. An interaction between rs10883463 and olive oil intake on the [18:1/18:0] desaturase index was found (p = 0.009). We also showed that genetic variations in the SCD1 gene were associated with obesity.

CONCLUSION

Our results show a relationship between genetic variation of the SCD1 gene, enzyme activity, and the risk of obesity, an association that is not independent of the type of oil consumed.

Metabolically healthy but obese, a matter of time? Findings from the prospective Pizarra study

BACKGROUND

Prospective longitudinal studies evaluating the relevance of "Metabolically Healthy but Obese" (MHO) phenotype at risk for type 2 diabetes mellitus (T2D) and cardiovascular diseases are few and results are contradictory.

METHODS

As a representative of the general population, 1051 individuals were evaluated in 1997-1998 and re-evaluated after 6 years and 11 years. Subjects without known T2D were given an oral glucose tolerance test. Anthropometric and biochemical variables were measured. Four sets of criteria were considered to define MHO subjects besides body mass index ≥30 kg/m(2): A: Homeostatic Model of Assessment-Insulin Resistance Index (HOMA-IR) <90th percentile; B: HOMA-IR <90th percentile, high-density lipoprotein cholesterol >40 mg/dL in men and high-density lipoprotein cholesterol >50 mg/dL in women, triglycerides <150 mg/dL, fasting glucose <110 mg/dL, and blood pressure ≤140/90 mm Hg; C: HOMA-IR <90th percentile, triglycerides <150 mg/dL, fasting glucose <110 mg/dL, and blood pressure ≤140/90 mm Hg; D: HOMA-IR <90th percentile, triglycerides <150 mg/dL, and fasting glucose <110 mg/dL. Subjects with T2D at baseline were excluded from the calculations of incidence of T2D.

RESULTS

The baseline prevalence of MHO phenotype varied between 3.0% and 16.9%, depending on the set of criteria chosen. Metabolically nonhealthy obese subjects were at highest risk for becoming diabetic after 11 years of follow-up (odds ratio = 8.20; 95% confidence interval = 2.72-24.72; P < .0001). In MHO subjects the risk for becoming diabetic was lower than in metabolically nonhealthy obese subjects, but this risk remained significant (odds ratio = 3.13; 95% confidence interval = 1.07-9.17; P = .02). In subjects who lost weight during the study, the association between MHO phenotype and T2D incidence disappeared, even after adjusting for HOMA-IR.

CONCLUSIONS

The results suggest that MHO is a dynamic concept that should be taken into account over time. As a clinical entity, it may be questionable.

Insulin resistance index (HOMA-IR) levels in a general adult population: curves percentile by gender and age. The EPIRCE study

AIMS

To describe the distribution of HOMA-IR levels in a general nondiabetic population and its relationships with metabolic and lifestyles characteristics.

METHODS

Cross-sectional study. Data from 2246 nondiabetic adults in a random Spanish population sample, stratified by age and gender, were analyzed. Assessments included a structured interview, physical examination, and blood sampling. Generalized additive models (GAMs) were used to assess the effect of lifestyle habits and clinical and demographic measurements on HOMA-IR. Multivariate GAMs and quantile regression analyses of HOMA-IR were carried out separately in men and women.

RESULTS

This study shows refined estimations of HOMA-IR levels by age, body mass index, and waist circumference in men and women. HOMA-IR levels were higher in men (2.06) than women (1.95) (P=0.047). In women, but not men, HOMA-IR and age showed a significant nonlinear association (P=0.006), with increased levels above fifty years of age. We estimated HOMA-IR curves percentile in men and women.

CONCLUSIONS

Age- and gender-adjusted HOMA-IR levels are reported in a representative Spanish adult non-diabetic population. There are gender-specific differences, with increased levels in women over fifty years of age that may be related with changes in body fat distribution after menopause.

PPARgamma expression after a high-fat meal is associated with plasma superoxide dismutase activity in morbidly obese persons

Peroxisome proliferator-activated receptor-gamma (PPARgamma) may play a protective role in the regulation of vascular function, partly mediated by its effects on superoxide dismutase (SOD). The aim of this study was to determine the association between PPARgamma expression in peripheral blood mononuclear cells (PBMCs) and SOD activity in morbidly obese persons with varying degrees of insulin resistance (IR). We studied in 10 morbidly obese persons (five with no IR and five with high IR) the effect of a high-fat meal on the plasma activity of various antioxidant enzymes and the mRNA expression of PPARgamma in PBMC. The high-fat meal resulted in a significant decrease in plasma SOD activity, glutathione reductase (GSH-Rd) activity, and mRNA expression of PPARgamma only in the group of morbidly obese persons with high IR. PPARgamma expression after the high-fat meal correlated with the IR levels (r = -0.803, P = 0.009) and the plasma SOD activity (r = 0.903, P = 0.001). Likewise, the reduction in PPARgamma expression correlated with the increase in free fatty acids (FFA) (r = 0.733, P = 0.016). In conclusion, the decreased expression of PPARgamma in PBMC in morbidly obese persons after a high-fat meal was associated with the state of IR, the plasma SOD activity, and the changes in the concentration of FFA.

Increased prevalence of insulin resistance in patients with differentiated thyroid carcinoma

BACKGROUND

Patients with insulin resistance (IR) have a higher prevalence of thyroid nodules. In the present study, we present original data showing that patients with differentiated thyroid carcinoma (DTC) also have a higher frequency of IR.

METHODS

Twenty women with DTC (group 1, G1) and 20 euthyroid individuals (control group, CG) were investigated for IR. G1 and CG subjects were matched in pairs by age, gender, and body mass index (BMI). The diagnosis of IR was made when the homeostasis model assesment of insulin resistance (HOMA-IR) index was higher than 2.5. According to the BMI, 20 women (10 with DTC and 10 of the CG) had a BMI < 25, whereas the other 20 had higher BMI values (overweight and obese patients).

RESULTS

IR was present in the 50% of G1, but only in the 10% of the CG (P < 0.001). In the groups with lower BMI (<25), we found IR in 30% of G1 and no cases in the CG, whereas in those with BMI > 25 the IR was present in 70% of G1 and 20% of CG. There were no differences between the two subgroups regarding the time in which the IR tests were performed. IR was present in 56.3% of patient with papillary anol 25% of follicular thyroid carcinomas, respectively.

CONCLUSIONS

We conclude that such a high prevalence of IR would be an important risk factor for developing DTC, as it is well known with some other nonthyroid carcinomas.

[Critical analysis on the use of the homeostasis model assessment (HOMA) indexes in the evaluation of the insulin resistance and the pancreatic beta cells functional capacity]

Beta-cell dysfunction and insulin resistance are interrelated metabolic abnormalities in the aetiology of Type 2 Diabetes. In several countries, increases in the prevalence of obesity and diabetes have been observed in association with the presence of insulin resistance. In this context, measurement of insulin resistance and beta-cell function is useful. The HOMA indexes (Homeostasis Model Assessment) have been widely used, representing an alternative for the evaluation of these parameters, particularly as a fast, easy and cheap method. This review discusses the origin and evolution of the HOMA index, as well as details of the method, analyzing features related to its validation and the cutoff limits for its interpretation.

Effect of long-term administration of cross-sex hormone therapy on serum and urinary uric acid in transsexual persons

BACKGROUND

Transsexual persons afford a very suitable model to study the effect of sex steroids on uric acid metabolism.

DESIGN

This was a prospective study to evaluate the uric acid levels and fractional excretion of uric acid (FEUA) in a cohort of 69 healthy transsexual persons, 22 male-to-female transsexuals (MFTs) and 47 female-to-male transsexuals (FMTs). The subjects were studied at baseline and 1 and 2 yr after starting cross-sex hormone treatment.

RESULTS

The baseline levels of uric acid were higher in the MFT group. Compared with baseline, uric acid levels had fallen significantly after 1 yr of hormone therapy in the MFT group and had risen significantly in the FMT group. The baseline FEUA was greater in the FMT group. After 2 yr of cross-sex hormone therapy, the FEUA had increased in MFTs (P = 0.001) and fallen in FMTs (P = 0.004). In MFTs, the levels of uric acid at 2 yr were lower in those who had received higher doses of estrogens (P = 0.03), and the FEUA was higher (P = 0.04). The FEUA at 2 yr was associated with both the estrogen dose (P = 0.02) and the serum levels of estradiol-17beta (P =0.03). In MFTs, a correlation was found after 2 yr of therapy between the homeostasis model assessment of insulin resistance and the serum uric acid (r = 0.59; P = 0.01).

CONCLUSIONS

Serum levels of uric acid and the FEUA are altered in transsexuals as a result of cross-sex hormone therapy. The results concerning the MFT group support the hypothesis that the lower levels of uric acid in women are due to estrogen-induced increases in FEUA.

Introducing the thyroid gland as another victim of the insulin resistance syndrome

BACKGROUND

Insulin is a thyroid growth factor that stimulates proliferation of thyroid cells in culture. In order to evaluate the effects of insulin resistance (IR) on the thyroid gland, we developed a prospective study in euthyroid women.

METHODS

One hundred eleven women (mean age 32.2 +/- 7 years) were evaluated by a thyroid ultrasound (US) and basal and postprandial serum insulin. Subjects were divided into four groups as follows: G1 (n = 42), subjects with IR and obesity; G2 (n = 21), subjects with obesity without IR; G3 (n = 17), subjects with IR and normal weight; and G4 (n = 31) control group (without IR and obesity).

RESULTS

The thyroid volume (TV), measured by US, showed the following values: G1, 17 +/- 3 mL; G2, 13.8 +/- 2.8 mL; G3, 16.2 +/- 2.1 mL; and G4,12.1 +/- 2.4 mL. There was no significant difference in TV between G1 and G3, but differences between G1 and G2, and between G3 and G4 were significant at p < 0.05. The percentage of nodular thyroid glands observed by US in each group was as follows: G1, 50%; G2, 23.8%; G3, 61%; G4, 16.1%. Again, the differences between G1 and G2 and between G3 and G4 were statistically significant (p < 0.005 and p < 0.001, respectively, for each comparison).

CONCLUSIONS

It is concluded that the higher circulating levels of insulin cause increased thyroid proliferation. The clinical manifestations are the larger thyroid volume and the formation of nodules. Thus, the thyroid gland appears to be another victim of the insulin resistance syndrome.

Incidence of type 2 diabetes in southern Spain (Pizarra Study)

BACKGROUND

Few European studies have used an oral glucose tolerance test (OGTT) to examine the incidence of type 2 diabetes. We determined the incidence of impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and type 2 diabetes in a population from southern Spain.

MATERIAL AND METHODS

A population-based cohort study was undertaken in Pizarra, Spain. Baseline data were recorded on age, sex, weight, height, waist and hip circumferences, and diabetes status for 1051 persons, of whom 910 were free of type 2 diabetes (at-risk sample). Of these, 714 completed the 6-year follow-up study. Body mass index, waist-to-hip ratio and weight increase since baseline were calculated. The homeostasis model assessment equations were used to estimate the indices of insulin resistance and beta-cell function. Each person received an OGTT at baseline and after 6 years.

RESULTS

Type 2 diabetes developed in 81 people for a total of 4253 person-years, representing an incidence of 19.1 cases per 1000 person-years (95% confidence interval, 15.3-23.6). Age and the presence of obesity, central obesity and carbohydrate metabolism disorders [IFG (cut off = 100 mg dL(-1), capillary blood glucose level), IGT or both] at baseline were significant markers for the onset of type 2 diabetes during follow-up. After adjusting for these variables, multivariate analysis showed weight increase, waist-to-hip ratio and the indices of insulin resistance and beta-cell function were significantly associated with the risk for type 2 diabetes.

CONCLUSIONS

The incidence of type 2 diabetes in a population from southern Spain is high. It is probably associated with the high prevalence of obesity and weight increase in this population.

Population-based incidence of type 2 diabetes in northern Spain: the Asturias Study

OBJECTIVE

The aim of this study was to define the incidence of type 2 diabetes in a low-risk Caucasian population in northern Spain and its association with various risk factors.

RESEARCH DESIGN AND METHODS

The Asturias Study is a prospective, population-based survey of diabetes and cardiovascular risk factors. The baseline examination was carried out during 1998-1999 when 1,034 individuals, aged 30-75 years, were randomly selected to determine the prevalence of type 2 diabetes and pre-diabetes in the Principality of Asturias (northern Spain). In 2004-2005, these same subjects were invited for a follow-up examination; 700 participated. This study includes only those individuals who did not have diabetes at baseline. We used the World Health Organization 1999 criteria to classify glucose metabolism at both baseline and follow-up.

RESULTS

The incidence of diabetes adjusted for the age and sex structure of Asturias was 10.8 cases/1,000 person-years (95% CI 8.1-14.8). The incidence rates were 5 cases/1,000 person-years in individuals with normoglycemia, 21 cases/1,000 person-years in individuals with isolated impaired glucose tolerance (IGT), 34.7 cases/1,000 person-years in individuals with isolated impaired fasting glucose (IFG), and 95.2 cases/1,000 person-years in individuals with combined IFG-IGT. Stepwise multiple logistic regression analysis showed that, together with fasting plasma glucose (FPG) and 2-h plasma glucose, which were the strongest predictors of diabetes, triglycerides and BMI were also independently associated with progression to diabetes.

CONCLUSIONS

In this 6-year prospective population-based study, we found an incidence of type 2 diabetes of 10.8 cases/1,000 person-years. Both FPG and 2-h plasma glucose were strongly predictive of diabetes, and their effect was additive.

Pro12Ala polymorphism of the PPARG2 gene is associated with type 2 diabetes mellitus and peripheral insulin sensitivity in a population with a high intake of oleic acid

Activation of the PPAR gamma 2 gene (PPARG2) improves the action of insulin and its lipid metabolism. We examined the association between Pro12Ala polymorphism of PPARG2, type 2 diabetes mellitus (DM2), and peripheral insulin sensitivity in a population with a high intake of oleic acid. A cross-sectional, population-based study was undertaken in Pizarra, a small town in the province of Malaga in southern Spain. A total of 538 subjects, aged 18-65 y, were selected randomly from the municipal census. All subjects underwent a clinical, anthropometrical, and biochemical evaluation, including an oral glucose tolerance test and Pro12Ala polymorphism of PPARG2. Insulin resistance was measured by homeostasis model assessment. Those subjects with the Ala-12 allele had an odds ratio for impaired fasting glucose of 0.55, for impaired glucose tolerance of 0.59, and for DM2 of 0.30. The intake of monounsaturated fatty acids (MUFA) contributed to the variance of the homeostasis model assessment insulin resistance index (HOMA IR) (P = 0.04), with a 2-way interaction between the Ala-12 allele of PPARG2 and the intake of MUFA (P = 0.005). The results suggest the existence of an interaction between Pro12Ala polymorphism of PPARG2 and dietary MUFA, such that obese people with the Ala-12 allele have higher HOMA IR values, especially if their intake of MUFA is low.

Dietary fatty acids and insulin secretion: a population-based study

OBJECTIVE

Few epidemiological studies have examined the relationship of dietary fatty acids, especially MUFA, with the interrelation between insulin secretion and insulin resistance. We assessed the relation of dietary fatty acids with insulin secretion in a free-living population.

DESIGN AND SETTING

This cross-sectional, population-based study was undertaken in Pizarra, a small town in Spain.

SUBJECTS AND METHODS

Anthropometrical data were collected for 1226 persons selected randomly from the municipal census, 538 of whom (randomly chosen) were given a prospective, quantitative, 7-day nutritional questionnaire. The fatty acid composition of the serum phospholipids was used as a biological marker of the type of fat consumed. Beta-cell function (betaCFI) and insulin-resistance index (IRI) were estimated by the Homeostasis Model Assessment.

RESULTS

To determine which factors influence the variability of the betaCFI, we analyzed the variance of the betaCFI according to sex, the presence of carbohydrate metabolism disorders and the different components of the diet, adjusting the models for age, body mass index (BMI) and IRI. The dietary MUFA and polyunsaturated fatty acids (PUFA) contributed to the variability of the betaCFI, whereas only the proportion of serum phospholipid MUFA, but neither the saturated fatty acids nor the PUFA accounted for part of the variability of the betaCFI in a multiple regression analysis.

CONCLUSION

The results of this population-based study corroborate the results of other clinical and experimental studies suggesting a favorable relationship of MUFA with beta-cell insulin secretion.

SPONSORSHIP

Fondo de Investigación Sanitaria, Junta de Andalucía and the Asociación Maimónides.

Serum insulin, insulin resistance, beta-cell dysfunction, and gallstone disease among type 2 diabetics in Chinese population: a community-based study in Kinmen, Taiwan

AIM

To explore the association of serum insulin, insulin resistance, and beta-cell dysfunction with gallstone disease (GSD) in type 2 diabetics.

METHODS

We used a community-based study conducted between 1991 and 1993 in Kinmen, Taiwan to identify type 2 diabetics. A screening program for GSD was performed in 2001 by a panel of specialists who employed real-time ultrasound sonography to examine the abdominal region after the patient had fasted for at least 8 h. Screening was conducted in 2001 on 848 patients diagnosed with type 2 diabetes. The HOMA method was used to compare the profile differences for insulin resistance (HOMA IR) and beta-cell dysfunction (HOMA beta-cell).

RESULTS

We studied 440 type 2 diabetics who attended sonography check-ups. After excluding eight insulin-treated diabetics, the prevalence of GSD among the remaining 432 was 13.9% (26/187) among males and 14.7% (36/245) among females. After adjustment for other GSD-associated risk factors in addition to age and obesity, GSD risk increased among females with levels of serum insulin [4(th) vs 1(st) quartile odds ratios (OR) = 4.46 (95%CI: 1.71-11.66)] and HOMA IR [4(th) vs 1(st) quartile OR = 4.46 (95%CI: 1.71-11.66)]. Better HOMA beta-cell function was significantly related to decreased risk of GSD [4(th) vs 1(st) quartile OR = 0.16 (95%CI: 0.03-1.70)]. Among males, age and central obesity were the most significant risk factors for GSD. No association of GSD with serum insulin, HOMA IR, and HOMA beta-cell was observed among males.

CONCLUSION

Serum insulin, insulin resistance, and beta-cell dysfunction are risk factors for GSD in females, but not males with type 2 diabetes.

Prevalencia del síndrome metabólico (criterios del ATP-III). Estudio de base poblacional en áreas rural y urbana de la provincia de Segovia

BACKGROUND AND OBJECTIVE

We aimed to estimate the prevalence of the Metabolic Syndrome (MS) in rural and urban areas of the Province of Segovia, Spain, according to the ATPIII criteria (National Cholesterol Education Program's Adults Treatment Panel III report) modified.

SUBJECTS AND METHOD

Cross-sectional design. Randomized and representative sample of 809 individuals (46% males) aged 35-74 years. Residents in urban and rural areas of the Province of Segovia (Spain). Period of study from January 2000 to January 2003.

RESULTS

The age/sex standardized prevalence of the MS was 17%; 15.7% in males and 18.1% in females. No significant differences in MS prevalence between rural and urban areas were found. The most frequent combination of individual components of MS was abdominal obesity, hyperglycemia and arterial hypertension in males and females. MS was associated with age and obesity in an adjusted logistic regression model. In a second model, abdominal obesity was more common in those individuals with a BMI over 30 kg/m2, secondary education level, age over 45 years, and in female residents in rural areas.

CONCLUSIONS

The sex/age adjusted prevalence was lower than that reported in other studies using the ATPIII criteria in Spain. Abdominal obesity was the most frequent single component of MS in females whereas it was arterial hypertension in males.