Incidence of type 2 diabetes in the elderly in Central Spain: Association with socioeconomic status, educational level, and other risk factors

AIMS

To analyze the incidence of type 2 diabetes (T2D) in Central Spain and its association with the socioeconomic status (SES), educational level, and other risk factors (RF) in the elderly population of three communities.

METHODS

Data for 5278 elderly participants (≥65 years old) were obtained using a census population-based survey. There was a first and a second survey three years later. The association between SES, educational level, RF, and T2D incidence was analyzed.

RESULTS

The incidence rate for T2D was 9.8/1000 person-years without gender differences. Incident T2D was associated with low SES and lower educational levels. Baseline and follow-up BMI were also the main RFs for T2D. Communities' incidence rates were: (1) Margarita, working-class area: 11.3/1000 person-years; (2) Arévalo, agricultural region: 10.1/1000 person-years and; (3) Lista, professional high-income class area: 7.6/1000 person-years.

CONCLUSION

We found an incidence rate of 9.8/1000 person-years of T2D in the elderly population. The risk of T2D was associated with a lower income and educational level. An increase in BMI may mediate this association. Our results emphasize the necessity of strategies for the prevention of diabetes that includes an approach to SES, educational levels, and other RF among older individuals in Spanish community settings.

Common variants in Alzheimer's disease and risk stratification by polygenic risk scores

Genetic discoveries of Alzheimer's disease are the drivers of our understanding, and together with polygenetic risk stratification can contribute towards planning of feasible and efficient preventive and curative clinical trials. We first perform a large genetic association study by merging all available case-control datasets and by-proxy study results (discovery n = 409,435 and validation size n = 58,190). Here, we add six variants associated with Alzheimer's disease risk (near APP, CHRNE, PRKD3/NDUFAF7, PLCG2 and two exonic variants in the SHARPIN gene). Assessment of the polygenic risk score and stratifying by APOE reveal a 4 to 5.5 years difference in median age at onset of Alzheimer's disease patients in APOE ɛ4 carriers. Because of this study, the underlying mechanisms of APP can be studied to refine the amyloid cascade and the polygenic risk score provides a tool to select individuals at high risk of Alzheimer's disease.

A Body Shape Index (ABSI) and Hip Index (HI) Adjust Waist and Hip Circumferences for Body Mass Index, But Only ABSI Predicts High Cardiovascular Risk in the Spanish Caucasian Population

Background: Our aim in this study was to investigate if Hip index (HI) improves the identification of cardiovascular risk (CVR) beyond that achieved with either the waist-to-height ratio (WHtR) or body mass index (BMI)-adjusted waist circumference (A body shape index [ABSI]) in the Spanish Caucasian population. Methods: Three thousand eight hundred forty-four subjects (1754 males, response rate 75.8%) were included. Anthropometric indices (AIs) included were HI, ABSI, and WHtR. CVR was estimated using the Framingham, Systematic COronary Risk Evaluation (SCORE), and American College of Cardiology/American Heart Association (ACC/AHA) charts. Areas under the receiver operating characteristic curve (AUC) were obtained to evaluate the performance of AIs in detecting CVR. We also estimated the AIs' standardized Z-scores and compared them against the CVR. Results: AUC demonstrated that the best AI in males to estimate higher CVR according to Framingham and ACC/AHA charts was WHtR. In females, WHtR also achieved good performance and showed higher prediction capacity than the other AIs. After transforming to Z-scores, ABSI was the best linear predictor for CVR according to SCORE and ACC/AHA, although WHtR also proved to be good. HI did not associate with the measures of CVR. Conclusions: HI does not predict high CVR in the Spanish Caucasian Population. However, ABSI is directly and linearly related to high CVR, with a higher performance than WHtR when standardized and evaluated as a linear predictor.

Body fat anthropometric indexes: Which of those identify better high cardiovascular risk subjects? A comparative study in Spanish population

Aim

To determine the association of body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR), waist to height ratio (WHtr) and Body Shape Index (ABSI) with high cardiovascular risk (CVR), as well as to determine whether how strong are these relationships.

Material and methods

A cross-sectional study was carried out in Spanish Caucasian adults. 3,456 subjects completed the study, 45.78% males, aged < 65 years and non-diabetic subjects. Anthropometric/biochemical variables were measured. We determined ABSI based on WC adjusted for height and weight. High CVR was defined as ≥ 20% according to the Framingham chart, ≥ 5% with the SCORE chart, and ≥ 7.5% with the ACC/AHA guide. Areas under the receiver operating characteristic curves (AUCs) were estimated for each anthropometric measure.

Results

Most significant AUCs in males were: WHtr and ABSI for Framingham ≥ 20% and SCORE ≥ 5%. Also significant were WHtr, WC and ABSI for ACCA/AHA ≥ 7.5%. On the other hand, most significant AUCs in females were: WHtr and WC for Framingham ≥ 20%; and WHtr and WHR for SCORE ≥ 5%, WHtr, and WC for ACC/AHA guide ≥ 7.5%.

Conclusions

Overall, the best anthropometric index identifying Spanish males and females who are at high risk for CV events is WHtr. ABSI was also found to be a good anthropometric index to predict high CVR in Spanish males according to FR, SCORE and ACC/AHA charts. For Spanish females, WC is a good anthropometric index according to FR and ACC/AHA guide, while WHR is better according to SCORE.

Prevalence, Treatment, and Associated Factors of Hypertension in Spain: A Comparative Study between Populations

The prevalence and related factors of hypertensive subjects according to the resident area (rural versus urban) were investigated in two population-based studies from Spain. Medical questionnaires were administered and anthropometrics were measured, using standardized protocols. Hypertension was diagnosed in pharmacology treated subjects or those with blood pressure (BP) ≥140/90 mm Hg. Regarding BP control, it was defined as under control if BP was <140/90 or <140/85 mm Hg in type 2 diabetic subjects. Information on educational status, social class, smoking habit, and alcohol intake was obtained. 3,816 subjects (54.38 % women) were included. Prevalence of diagnosed hypertension was higher in women and showed no differences according to the living area (men: urban 21.88 versus rural 21.92 %, p = 0.986; women: urban 28.73 versus rural 30.01 %, p = 0.540). Women living in rural areas and men with secondary or tertiary education levels had a lower probability of being BP uncontrolled (OR (95 % CI): 0.501 (0.258-0.970)/p=0.040, 0.245 (0.092-0.654)/p=0.005, and 0.156 (0.044-0.549)/p=0.004, respectively). Urban young men (31-45 years) and medium aged women (46-60 years) were less BP controlled than their rural counterparts (41.30 versus 65.79 %/p=0.025 and 35.24 versus 53.27 %/p=0.002, respectively).

Genome-wide significant risk factors on chromosome 19 and the APOE locus

The apolipoprotein E (APOE) gene on chromosome 19q13.32, was the first, and remains the strongest, genetic risk factor for Alzheimer’s disease (AD). Additional signals associated with AD have been located in chromosome 19, including ABCA7 (19p13.3) and CD33 (19q13.41). The ABCA7 gene has been replicated in most populations. However, the contribution to AD of other signals close to APOE gene remains controversial. Possible explanations for inconsistency between reports include long range linkage disequilibrium (LRLD). We analysed the contribution of ABCA7 and CD33 loci to AD risk and explore LRLD patterns across APOE region. To evaluate AD risk conferred by ABCA7 rs4147929:G>A and CD33 rs3865444:C>A, we used a large Spanish population (1796 AD cases, 2642 controls). The ABCA7 rs4147929:G>A SNP effect was nominally replicated in the Spanish cohort and reached genome-wide significance after meta-analysis (odds ratio (OR)=1.15, 95% confidence interval (95% CI)=1.12–1.19; P = 1.60 x 10^-19). CD33 rs3865444:C>A was not associated with AD in the dataset. The meta-analysis was also negative (OR=0.98, 95% CI=0.93–1.04; P=0.48). After exploring LRLD patterns between APOE and CD33 in several datasets, we found significant LD (D’ >0.20; P <0.030) between APOE-Ɛ2 and CD33 rs3865444C>A in two of five datasets, suggesting the presence of a non-universal long range interaction between these loci affecting to some populations. In conclusion, we provide here evidence of genetic association of the ABCA7 locus in the Spanish population and also propose a plausible explanation for the controversy on the contribution of CD33 to AD susceptibility.

MAPT H1 Haplotype is Associated with Late-Onset Alzheimer's Disease Risk in APOEɛ4 Noncarriers: Results from the Dementia Genetics Spanish Consortium

The MAPT H1 haplotype has been linked to several disorders, but its relationship with Alzheimer's disease (AD) remains controversial. A rare variant in MAPT (p.A152T) has been linked with frontotemporal dementia (FTD) and AD. We genotyped H1/H2 and p.A152T MAPT in 11,572 subjects from Spain (4,327 AD, 563 FTD, 648 Parkinson's disease (PD), 84 progressive supranuclear palsy (PSP), and 5,950 healthy controls). Additionally, we included 101 individuals from 21 families with genetic FTD. MAPT p.A152T was borderline significantly associated with FTD [odds ratio (OR) = 2.03; p = 0.063], but not with AD. MAPT H1 haplotype was associated with AD risk (OR = 1.12; p = 0.0005). Stratification analysis showed that this association was mainly driven by APOE ɛ4 noncarriers (OR = 1.14; p = 0.0025). MAPT H1 was also associated with risk for PD (OR = 1.30; p = 0.0003) and PSP (OR = 3.18; p = 8.59 × 10-8) but not FTD. Our results suggest that the MAPT H1 haplotype increases the risk of PD, PSP, and non-APOE ɛ4 AD.

Low Physical Activity and Its Association with Diabetes and Other Cardiovascular Risk Factors: A Nationwide, Population-Based Study

Low physical activity (PA), or sedentary lifestyle, is associated with the development of several chronic diseases. We aimed to investigate current prevalence of sedentariness and its association with diabetes and other cardiovascular risk factors. PA was evaluated in a population-based, cross-sectional, randomly sampled study conducted in 2009-2010 in Spain. International Physical Activity Questionnaire (SF-IPAQ) was used to assess PA. 4991 individuals (median age 50 years, 57% women) were studied. Prevalence of sedentariness was 32.3% for men and 39% for women (p < 0.0001). Sex differences were particularly notable (age*sex interaction, p = 0.0024) at early and older ages. Sedentary individuals had higher BMI (28 vs. 27 kg/m2) and obesity prevalence (37 vs. 26%). Low PA was present in 44, 43, and 38% of individuals with known diabetes (KDM), prediabetes/unknown-diabetes (PREDM/UKDM), and normal glucose regulation (p = 0.0014), respectively. No difference between KDM and PREDM/UKDM (p = 0.72) was found. Variables independently associated (p < 0.05) with sedentariness were age, sex, BMI, central obesity, Mediterranean diet adherence, smoking habit, HDL-cholesterol, triglycerides and dyslipidemia. Low PA is on the rise in Spain, especially among women. Sedentariness is associated with several cardiovascular risk factors and may be responsible for the increasing prevalence of obesity and diabetes in this country.

Metabolic syndrome, glucose tolerance categories and the cardiovascular risk in Spanish population

We examined the prevalence of metabolic syndrome (MetS), glucose tolerance categories and risk factors of cardiovascular-disease (CVD) in the general Spanish population. We studied 3844 randomly sampled subjects (46% males) aged 35-74 years. Glucose tolerance categories were defined according to the 2003 ADA and MetS according to the Harmonized Consensus Criteria with waist circumference (WC) cut-off-points previously reported in Spanish population (≥94.5/≥89.5cm for males/females). The prevalences of normoglycemia (NG), impaired fasting glucose (IFG), impaired glucose tolerance (IGT), IFG and IGT considered together (IFG/IGT), and diabetes mellitus (DM) were 67.6/16.6/5.0/3.3, and 7.5%, respectively. The overall prevalence of MetS was 31.2%. In subjects with NG, IFG, IGT, IFG/IGT, and DM the MetS prevalence's were 16.3/57.1/31.5/66.1, and 74.4% (p<0.001), respectively. MetS was more common in males, older subjects, smokers, and/or individuals with obesity, IFG, IFG/IGT, DM, or insulin resistance (HOMA-IR ≥3.8). MetS was less prevalent in individuals with low alcohol intake and/or high education level. Regarding the risk level of CVD estimated by Framingham and SCORE risk charts, IGT had higher estimated CVD-risk than IFG and IFG/IGT. The presence of MetS increases the risk 4.85 times by Framingham and 2.43 times by SCORE. Prevalence of prediabetes (IFG/IGT) and MetS were 25% and 31.2% respectively. Prevalence of MetS has not changed in the past decade in Spanish females, but has slightly increased in males. We found that subjects with IGT showed a higher risk of CVD than IFG and IFG/IGT according to the Framingham and SCORE. MetS increased the CVD-risk previously estimated by Framingham and SCORE.

Prevalence, Diagnosis, Treatment, and Control of Hypertension in Spain. Results of the Di@bet.es Study

INTRODUCTION AND OBJECTIVES

Di@bet.es is a national study designed to estimate the prevalence of diabetes mellitus and other cardiovascular risk factors in the Spanish adult population. The prevalence of hypertension and the degree to which it is recognized, treated, and controlled are described.

METHODS

The study included a sample of the Spanish population with 5048 adults aged ≥ 18 years. Patients were questioned and examined, with 3 blood pressure readings while seated and at rest to calculate the mean of the 3 readings. Hypertension was defined as systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg and/or prescription for antihypertensive drug therapy.

RESULTS

Hypertension was found in 42.6% of the Spanish adult population aged ≥ 18 years and was more common among men (49.9%) than women (37.1%). The prevalence was higher among prediabetics (67.9%) and diabetics (79.4%). Undiagnosed hypertension was identified in 37.4% of patients and was more common in men (43.3%) than in women (31.5%). Among patients with known hypertension, 88.3% were receiving drug therapy. Well-controlled blood pressure was found in only 30% and was more common among women (24.9%) than men (16%).

CONCLUSIONS

The prevalence of hypertension in Spain is high, and a considerable percentage of hypertensive patients have still not been diagnosed. Hypertension is associated with diabetes and prediabetes, and although drug therapy is increasingly common, the degree of control has not improved and remains low. Population campaigns should be developed and promoted for hypertension prevention, detection, and treatment.

Profile of individuals who are metabolically healthy obese using different definition criteria. A population-based analysis in the Spanish population

BACKGROUND

Obesity is associated with numerous metabolic complications such as diabetes mellitus type 2, dyslipidemia, hypertension, cardiovascular diseases and several forms of cancer. Our goal was to compare different criteria to define the metabolically healthy obese (MHO) with metabolically unhealthy obese (MUHO) subjects. We applied Wildman (W), Wildman modified (WM) with insulin resistance (IR) with cut-off point ≥ 3.8 and levels of C- Reactive Protein (CRP) ≥ 3 mg/l; and Consensus Societies (CS) criteria. In these subjects cardiovascular-risk (CV-risk) was estimated by Framingham score and SCORE for MHO and MUHO.

METHODS

A cross-sectional study was conducted in Spanish Caucasian adults. A total of 3,844 subjects completed the study, 45% males, aged 35-74 years. Anthropometric/biochemical variables were measured. Obesity was defined as BMI: ≥ 30 Kg/m(2).

RESULTS

The overall prevalence of obesity in our population was 27.5%, (23.7%/males and 30.2%/females). MHO prevalence according to W, WM, and CS definition criteria were: 9.65%, 16.29%, 39.94% respectively in obese participants. MHO has lower waist circumference (WC) measurements than MUHO. The estimated CV-risks by Framingham and SCORE Project charts were lower in MHO than MUHO subjects. WC showed high specificity and sensitivity in detecting high estimated CV risk by Framingham. However, WHR showed high specificity and sensitivity in detecting CV risk according to SCORE Project. MHO subjects as defined by any of the three criteria had higher adiponectin levels after adjustment by sex, age, WC, HOMA IR and Framingham or SCORE risks. This relationship was not found for CRP circulating levels neither leptin levels.

CONCLUSIONS

MHO prevalence is highly dependent on the definition criteria used to define those individuals. Results showed that MHO subjects had less WC, and a lower estimated CV-risk than MUHO subjects. Additionally, the high adiponectin circulating levels in MHO may suggest a protective role against developing an unhealthy metabolic state.

Variable patterns of obesity and cardiometabolic phenotypes and their association with lifestyle factors in the Di@bet.es study

BACKGROUND AND AIM

Prevalence rates of "metabolically healthy obese" (MHO) subjects vary depending on the criteria used. This study examined the prevalence and characteristics of MHO subjects and metabolically abnormal normal-weight subjects and compared the findings with the NHANES 1999-2004 study. The aims of the present study were, first, to determine the prevalence rates of MHO and MNHNO subjects using the same criteria as those of the National Health and Nutrition Examination Survey (NHANES) (1999-2004) study, and second to compare the prevalence and correlates of obese subjects who are resistant to the development of adiposity-associated cardiometabolic abnormalities (CA) and normal-weight individuals who display cardiometabolic risk factor clustering between the Spanish and the US populations.

METHODS AND RESULTS

Di@bet.es study is a national, cross-sectional population-based survey of 5728 adults conducted in 2009-2010. Clinical, metabolic, sociodemographic, and anthropometric data and information about lifestyle habits, such as physical activity, smoking habit, alcohol intake and food consumption, were collected. Subjects were classified according to their body mass index (BMI) (normal-weight, <25 kg/m(2); overweight, 25-29.9 kg/m(2); and obese, >30 kg/m(2)). CA included elevated blood pressure; elevated levels of triglycerides, fasting glucose, and high-sensitivity C-reactive protein (hs-CRP); and elevated homeostasis model assessment of insulin resistance (HOMA-IR) value and low high-density lipoprotein cholesterol (HDL-c) level. Two phenotypes were defined: metabolically healthy phenotype (0-1 CA) and metabolically abnormal phenotype (≥2 CA). The prevalence of metabolically abnormal normal-weight phenotype was slightly lower in the Spanish population (6.5% vs. 8.1%). The prevalence of metabolically healthy overweight and MHO subjects was 20.9% and 7.0%, respectively, while in NHANES study it was 17.9% and 9.7%, respectively. Cigarette smoking was associated with CA in each phenotype, while moderate physical activity and moderate alcohol intake were associated with being metabolically healthy. Olive oil intake was negatively associated with the prevalence of CA.

CONCLUSIONS

Smoking, physical activity level, and alcohol intake contribute to the explanation of the prevalence of CA in the Spanish population, as in the US population. However in Spain, olive oil intake contributes significantly to the explanation of the variance in the prevalence of CA.

Risk factors associated with retinal vein occlusion

AIMS

Retinal vein occlusion (RVO) is the most frequent retinal vascular disease after diabetic retinopathy in which arterial risk factors are much more relevant than venous factors. The objective was to evaluate the role of risk factors in the development of the first episode of RVO.

SUBJECTS AND METHODS

One hundred patients with RVO [mean age 56 years, 42% females and mean body mass index (BMI) 27.5 kg/m(2)] were recruited consecutively from the outpatient clinic of a tertiary hospital in Valencia (Spain). All subjects underwent clinical assessment including anthropometric and blood pressure measurements and laboratory test including homocysteine, antiphospholipid antibodies (aPLAs) and thrombophilia studies. In half of the subjects, a carotid ultrasonography was performed. Three control populations matched by age, sex and BMI from different population-based studies were used to compare the levels and prevalence of arterial risk factors. One cohort of young patients with venous thromboembolic disease was used to compare the venous risk factors.

RESULTS

Blood pressure levels and the prevalence of hypertension were significantly higher in the RVO population when compared with those for the general populations. There was also a large proportion of undiagnosed hypertension within the RVO group. Moreover, carotid evaluation revealed that a large proportion of patients with RVO had evidence of subclinical organ damage. In addition, homocysteine levels and prevalence of aPLAs were similar to the results obtained in our cohort of venous thromboembolic disease.

CONCLUSIONS

The results indicate that hypertension is the key factor in the development of RVO, and that RVO can be the first manifestation of an undiagnosed hypertension. Furthermore, the majority of these patients had evidence of atherosclerotic disease. Among the venous factors, a thrombophilia study does not seem to be useful and only the prevalence of hyperhomocysteinaemia and aPLAs is higher than in the general population.

Use of drugs related to the treatment of diabetes mellitus and other cardiovascular risk factors in the Spanish population. The Di@bet.es study

INTRODUCTION AND OBJECTIVES

To assess the patterns of use of 8 therapeutic drug groups for the treatment of diabetes mellitus and other cardiovascular risk factors, and to identify sociodemographic and health determinants of their use in the overall Spanish population.

METHODS

A representative sample of the Spanish population within the Di@bet.es study, a cross-sectional population-based survey, was included.

STUDY VARIABLES

sociodemographic, clinical, and lifestyle data; physical examination, and an oral glucose tolerance test in patients without known diabetes mellitus. Furthermore, patients were systematically queried about current medication use, and 8 pharmacotherapeutic groups were evaluated: lipid-lowering therapy, antihypertensives, oral hypoglycemic agents, insulin, thyroid hormone, uricosurics, psychoactive drugs, and nonsteroidal anti-inflammatory drugs.

RESULTS

Sixty-six percent of the Spanish population was taking at least one medication. Therapeutic drug use was associated with age, independently of the higher prevalence of diabetes mellitus, hypertension, or hyperlipidemia in older patients. Sex disparities were found in the use of lipid-lowering agents, allopurinol, levothyroxine, nonsteroidal anti-inflammatory drugs, and psychoactive drugs. Use of psychoactive drugs was related to education level, work status, physical activity, smoking, and alcohol consumption. Almost 30% of patients with diabetes mellitus were taking 6 or more medications daily. Diabetes mellitus was associated with greater use of antihypertensives, lipid-lowering agents, and nonsteroidal anti-inflammatory drugs.

CONCLUSIONS

Age and sex are the most important factors determining therapeutic drug use. Lifestyle patterns and sociocultural factors have an impact only on psychoactive drug use. Diabetes mellitus is associated with greater use of antihypertensives, lipid-lowering agents, and nonsteroidal anti-inflammatory drugs.

Clinical decisions in patients with diabetes and other cardiovascular risk factors. A statement of the Spanish Society of Internal Medicine

Although the mortality associated to cardiovascular diseases (CVD) has been reduced in the last decades, CVD remains the main cause of mortality in Spain and they are associated with an important morbidity and a huge economic burden. The increasing prevalence of obesity and diabetes could be slowing down the mortality reduction in Spain. Clinicians have often difficulty making clinical decisions due to the multiple clinical guidelines available. Moreover, in the current context of economic crisis it is critical to promote an efficient use of diagnostic and therapeutic proceedings to ensure the viability of public health care systems. The Spanish Society of Internal Medicine (SEMI) has coordinated a consensus document to answer questions of daily practice with the aim of facilitating physicians' decision-making in the management of diabetes and cardiovascular risk factors from a cost-efficiency point of view.

Metabolic syndrome, adiponectin, and cardiovascular risk in Spain (the Segovia study): impact of consensus societies criteria

BACKGROUND

We aimed to investigate the prevalence of metabolic syndrome in rural and urban areas in the province of Segovia, Spain, and its relationship to lifestyle habits, cardiovascular risk, and serum adiponectin concentrations.

METHODS

The study had a cross-sectional design and included 888 individual residents in the province of Segovia, Autonomous Community of Castilla-León.

RESULTS

The age/sex standardized prevalence of the metabolic syndrome was by: (1) American Heart Association/National Heart Lung and Blood Institute criteria (AHA/NHLBI), 17%; (2) International Diabetes Federation (IDF), 24.3%; and (3) Consensus Societies/Joint Interim Statement (CS), 27.8%. A high correlation was found between the different criteria. No formal education [odds ratio (OR) 6.9 (2.4-20.2)] and primary education [6.7 (2.8-15.9)] were independently associated with metabolic syndrome. An inverse association with metabolic syndrome was found for subjects doing a high level of exercise during work [0.4 (0.2-0.7)] as well as those who were mild drinkers [alcohol intake of less than 15 grams/daily, 0.4 (0.3-0.8)]. Among subjects with low estimated cardiovascular risk, adiponectin levels are higher in those who do not meet criteria of metabolic syndrome. A total of 29.7% of subjects meeting CS criteria had >20% 10-year predicted risk of cardiovascular disease (CVD) by the Framingham risk score criteria [4.5 (2.4-8.5)].

CONCLUSIONS

Our results show: (1) A higher estimated prevalence of metabolic syndrome according to IDF and CS criteria. (2) Low educational level was independently associated with metabolic syndrome. A high level of physical activity and a daily alcohol intake of less than 15 grams/day were inversely associated with metabolic syndrome. (3) Metabolic syndrome increases the predicted CVD risk. (4) Adiponectin levels are not inversely related to insulin resistance in subjects with high cardiovascular risk and metabolic syndrome.

Common genetic variants of surfactant protein-D (SP-D) are associated with type 2 diabetes

Context

Surfactant protein-D (SP-D) is a primordial component of the innate immune system intrinsically linked to metabolic pathways. We aimed to study the association of single nucleotide polymorphisms (SNPs) affecting SP-D with insulin resistance and type 2 diabetes (T2D).

Research Design and Methods

We evaluated a common genetic variant located in the SP-D coding region (rs721917, Met³¹Thr) in a sample of T2D patients and non-diabetic controls (n = 2,711). In a subset of subjects (n = 1,062), this SNP was analyzed in association with circulating SP-D concentrations, insulin resistance, and T2D. This SNP and others were also screened in the publicly available Genome Wide Association (GWA) database of the Meta-Analyses of Glucose and Insulin-related traits Consortium (MAGIC).

Results

We found the significant association of rs721917 with circulating SP-D, parameters of insulin resistance and T2D. Indeed, G carriers showed decreased circulating SP-D (p = 0.004), decreased fasting glucose (p = 0.0002), glycated hemoglobin (p = 0.0005), and 33% (p = 0.002) lower prevalence of T2D, estimated under a dominant model, especially among women. Interestingly, these differences remained significant after controlling for origin, age, gender, and circulating SP-D. Moreover, this SNP and others within the SP-D genomic region (i.e. rs10887344) were significantly associated with quantitative measures of glucose homeostasis, insulin sensitivity, and T2D, according to GWAS datasets from MAGIC.

Conclusions

SP-D gene polymorphisms are associated with insulin resistance and T2D. These associations are independent of circulating SP-D concentrations.

Associations between surrogate measures of insulin resistance and waist circumference, cardiovascular risk and the metabolic syndrome across Hispanic and non-Hispanic white populations

AIMS

We evaluated the relations between surrogate indices of insulin resistance and waist circumference, metabolic syndrome and coronary heart disease risk across Hispanic and non-Hispanic white populations.

METHODS

The study was a cross-sectional analysis of participants without diabetes in the San Antonio Heart Study, Mexico City Diabetes Study and Spanish Insulin Resistance Study. We evaluated commonly used indices of insulin resistance, including homeostasis model assessment, McAuley's index, Gutt's insulin sensitivity index, Avignon's insulin sensitivity index and the Stumvoll index with and without demographics, the modified Matsuda index and the product of the triglycerides and glucose index. The metabolic syndrome was defined by American Heart Association/National Heart, Lung, and Blood Institute criteria and coronary heart disease risk by Framingham risk scores.

RESULTS

The Stumvoll index with demographics and the Avignon's insulin sensitivity index had the strongest correlations with waist circumference across populations. The triglycerides and glucose and McAuley's indices had the most robust correlations with Framingham risk score. The triglycerides and glucose index had the greatest ability to detect individuals with the metabolic syndrome and ≥ 10% coronary heart disease risk. Some indices display significant variability in the strength of the relationship with adiposity and coronary heart disease risk across populations.

CONCLUSIONS

There are significant differences between insulin resistance indices regarding the ability to detect the metabolic syndrome and coronary heart disease risk across populations. Studies may need to consider the index of insulin resistance that best suits the objectives.

An SNP in the Adiponectin Gene Is Associated with Decreased Serum Adiponectin Levels and Risk for Impaired Glucose Tolerance

Adiponectin is a plasma protein produced by the adipose tissue. Hypoadiponectinemia has been associated with insulin resistance and several components of the metabolic syndrome (MS): type 2 diabetes, obesity, and dyslipidemia. We investigated whether single nucleotide polymorphisms (SNPs) at positions 45 and 276 in the adiponectin gene were associated with features of the MS in 747 unrelated Spanish subjects. The G allele of SNP45 and the G/G genotype of SNP276 were associated with impaired glucose tolerance (p = 0.020 and 0.042, respectively). The G/G genotype for SNP276 was associated with lower serum adiponectin levels as compared with the G/T and T/T genotypes (G/G, 10.10 +/- 0.24 microg/mL; G/T, 10.98 +/- 0.32 microg/mL; T/T, 12.00 +/- 0.92 microg/mL; p = 0.015) even after adjustment for sex, age, BMI, waist-to-hip ratio, homeostasis model assessment index, and the degree of glucose tolerance (p = 0.040). We found a significant negative association of circulating adiponectin levels with waist-to-hip ratio (r = -0.42, p < 0.001), sagittal abdominal diameter (r = -0.24, p < 0.001), triglycerides (r = -0.32, p < 0.001), homeostasis model assessment index (r = -0.14, p = 0.001), and uric acid (r = -0.36, p < 0.001) and positive association with high-density lipoprotein-cholesterol (r = 0.41, p < 0.001). Our findings indicate that serum adiponectin levels are associated with several components of the MS. The SNP276 of the adiponectin gene may affect impaired glucose tolerance and hypoadiponectinemia.

Central Adiposity Determines Prevalence Differences of the Metabolic Syndrome

OBJECTIVE

To compare the expression of the metabolic syndrome in Spain and San Antonio, TX, two populations with major differences regarding their cardiovascular risk profile.

RESEARCH METHODS AND PROCEDURES

Cross-sectional analysis of population-based, epidemiological surveys using the metabolic syndrome definition of the National Cholesterol Education Program. In San Antonio, we limited our analysis to non-Hispanic whites because non-Hispanic whites are largely of European ancestry (n = 1339 in San Antonio and 2947 in Spain)

RESULTS

In men, increased central adiposity was more prevalent in San Antonio than in Spain (29.7 vs. 23.0%, p < 0.0001); in women, it was less prevalent in San Antonio than in Spain (40.2 vs. 66.4%, p < 0.0001). The metabolic syndrome followed that same pattern: more prevalent in men (28.9 vs. 20.8%, p = 0.019) and less in women from San Antonio (27.1 vs. 30.9%, p < 0.0001). In subjects with the metabolic syndrome, most women had increased central adiposity (92.6% in San Antonio and 97.5% in Spain), and most men had either increased central adiposity or blood pressure (99.2% in San Antonio and 95.0% in Spain).

DISCUSSION

Contrary to men, the metabolic syndrome is more prevalent in Spanish women than in women from San Antonio with differences that mirror differences in central adiposity. Central adiposity and blood pressure may be used to exclude the metabolic syndrome. Considering recent secular trends in obesity, we predict there will be an increase in the prevalence of the metabolic syndrome in both populations in the coming years.

Common variants of the liver fatty acid binding protein gene influence the risk of type 2 diabetes and insulin resistance in Spanish population

Summary

The main objective was to evaluate the association between SNPs and haplotypes of the FABP1-4 genes and type 2 diabetes, as well as its interaction with fat intake, in one general Spanish population. The association was replicated in a second population in which HOMA index was also evaluated.

Methods

1217 unrelated individuals were selected from a population-based study [Hortega study: 605 women; mean age 54 y; 7.8% with type 2 diabetes]. The replication population included 805 subjects from Segovia, a neighboring region of Spain (446 females; mean age 52 y; 10.3% with type 2 diabetes). DM2 mellitus was defined in a similar way in both studies. Fifteen SNPs previously associated with metabolic traits or with potential influence in the gene expression within the FABP1-4 genes were genotyped with SNPlex and tested. Age, sex and BMI were used as covariates in the logistic regression model.

Results

One polymorphism (rs2197076) and two haplotypes of the FABP-1 showed a strong association with the risk of DM2 in the original population. This association was further confirmed in the second population as well as in the pooled sample. None of the other analyzed variants in FABP2, FABP3 and FABP4 genes were associated. There was not a formal interaction between rs2197076 and fat intake. A significant association between the rs2197076 and the haplotypes of the FABP1 and HOMA-IR was also present in the replication population.

Conclusions

The study supports the role of common variants of the FABP-1 gene in the development of type 2 diabetes in Caucasians.

A genome-wide association search for type 2 diabetes genes in African Americans

African Americans are disproportionately affected by type 2 diabetes (T2DM) yet few studies have examined T2DM using genome-wide association approaches in this ethnicity. The aim of this study was to identify genes associated with T2DM in the African American population. We performed a Genome Wide Association Study (GWAS) using the Affymetrix 6.0 array in 965 African-American cases with T2DM and end-stage renal disease (T2DM-ESRD) and 1029 population-based controls. The most significant SNPs (n = 550 independent loci) were genotyped in a replication cohort and 122 SNPs (n = 98 independent loci) were further tested through genotyping three additional validation cohorts followed by meta-analysis in all five cohorts totaling 3,132 cases and 3,317 controls. Twelve SNPs had evidence of association in the GWAS (P<0.0071), were directionally consistent in the Replication cohort and were associated with T2DM in subjects without nephropathy (P<0.05). Meta-analysis in all cases and controls revealed a single SNP reaching genome-wide significance (P<2.5×10(-8)). SNP rs7560163 (P = 7.0×10(-9), OR (95% CI) = 0.75 (0.67-0.84)) is located intergenically between RND3 and RBM43. Four additional loci (rs7542900, rs4659485, rs2722769 and rs7107217) were associated with T2DM (P<0.05) and reached more nominal levels of significance (P<2.5×10(-5)) in the overall analysis and may represent novel loci that contribute to T2DM. We have identified novel T2DM-susceptibility variants in the African-American population. Notably, T2DM risk was associated with the major allele and implies an interesting genetic architecture in this population. These results suggest that multiple loci underlie T2DM susceptibility in the African-American population and that these loci are distinct from those identified in other ethnic populations.

Genome-wide association identifies nine common variants associated with fasting proinsulin levels and provides new insights into the pathophysiology of type 2 diabetes

OBJECTIVE

Proinsulin is a precursor of mature insulin and C-peptide. Higher circulating proinsulin levels are associated with impaired β-cell function, raised glucose levels, insulin resistance, and type 2 diabetes (T2D). Studies of the insulin processing pathway could provide new insights about T2D pathophysiology.

RESEARCH DESIGN AND METHODS

We have conducted a meta-analysis of genome-wide association tests of ∼2.5 million genotyped or imputed single nucleotide polymorphisms (SNPs) and fasting proinsulin levels in 10,701 nondiabetic adults of European ancestry, with follow-up of 23 loci in up to 16,378 individuals, using additive genetic models adjusted for age, sex, fasting insulin, and study-specific covariates.

RESULTS

Nine SNPs at eight loci were associated with proinsulin levels (P < 5 × 10(-8)). Two loci (LARP6 and SGSM2) have not been previously related to metabolic traits, one (MADD) has been associated with fasting glucose, one (PCSK1) has been implicated in obesity, and four (TCF7L2, SLC30A8, VPS13C/C2CD4A/B, and ARAP1, formerly CENTD2) increase T2D risk. The proinsulin-raising allele of ARAP1 was associated with a lower fasting glucose (P = 1.7 × 10(-4)), improved β-cell function (P = 1.1 × 10(-5)), and lower risk of T2D (odds ratio 0.88; P = 7.8 × 10(-6)). Notably, PCSK1 encodes the protein prohormone convertase 1/3, the first enzyme in the insulin processing pathway. A genotype score composed of the nine proinsulin-raising alleles was not associated with coronary disease in two large case-control datasets.

CONCLUSIONS

We have identified nine genetic variants associated with fasting proinsulin. Our findings illuminate the biology underlying glucose homeostasis and T2D development in humans and argue against a direct role of proinsulin in coronary artery disease pathogenesis.

Association analysis of urotensin II gene (UTS2) and flanking regions with biochemical parameters related to insulin resistance

Background

Urotensin II (UII) is a potent vasoconstrictor peptide, which signals through a G-protein coupled receptor (GPCR) known as GPR14 or urotensin receptor (UTR). UII exerts a broad spectrum of actions in several systems such as vascular cell, heart muscle or pancreas, where it inhibits insulin release.

Objective

Given the reported role of UII in insulin secretion, we have performed a genetic association analysis of the UTS2 gene and flanking regions with biochemical parameters related to insulin resistance (fasting glucose, glucose 2 hours after a glucose overload, fasting insulin and insulin resistance estimated as HOMA).

Results and Conclusions

We have identified several polymorphisms associated with the analysed clinical traits, not only at the UTS2 gene, but also in thePER3 gene, located upstream from UTS2. Our results are compatible with a role for UII in glucose homeostasis and diabetes although we cannot rule out the possibility that PER3 gene may underlie the reported associations.

Lipid accumulation product: a powerful marker of metabolic syndrome in healthy population

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 test=78-85%). 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.

Risk factors associated with metabolic syndrome in type 2 diabetes mellitus patients according to World Health Organization, Third Report National Cholesterol Education Program, and International Diabetes Federation definitions

BACKGROUND

The availability of several definitions of the metabolic syndrome has created potential confusion concerning its prognostic utility. At present, little data exist about the risk factors associated with metabolic syndrome in diabetic patients.

AIM

To identify risk factors associated with metabolic syndrome in patients with type 2 diabetes mellitus according to three diagnostic criteria: World Health Organization (WHO), Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults - Adult Treatment Panel III (NCEP-ATP III), and International Diabetes Federation (IDF).

SUBJECTS AND METHODS

A logistic regression model was used to identify demographic, clinical, and lifestyle variables related with metabolic syndrome (N = 1259).

RESULTS

Hypertension, dyslipidemia, and glycosylated hemoglobin (HbA(1c)) ≥7% were associated with increased risk of WHO-defined metabolic syndrome (odds ratio [OR], 2.33; 95% confidence interval [CI]: 1.60-3.40; OR, 1.79 95% CI: 1.25-2.55; and OR, 1.58; 95% CI: 1.12-2.22, respectively). The risk of presenting metabolic syndrome according to NCEP-ATP III criteria was increased in female patients (OR, 2.02; 95% CI: 1.37-2.97), elevated fasting glucose levels (OR, 5.99; 95% CI: 3.56-10.07), dyslipidemia (OR, 2.28; 95% CI: 1.57-3.32), hypertension (OR, 2.36; 95% CI: 1.59-3.53), and endocrine disorders (OR, 1.64; 95% CI: 1.06-2.57). For the IDF criteria, female patients and patients with left ventricular hypertrophy or insulin treatment were at higher risk of metabolic syndrome (OR, 4.00; 95% CI: 2.35-6.80; OR, 2.72 95% CI: 1.22-6.04; and OR, 1.96 95% CI: 1.24-3.11, respectively).

CONCLUSIONS

The risk factors for metabolic syndrome in type 2 diabetes mellitus patients are highly dependent on the criteria used to define the syndrome, supporting the need for a single clinically useful and epidemiologically useful definition.

Common variants at 10 genomic loci influence hemoglobin A₁(C) levels via glycemic and nonglycemic pathways

OBJECTIVE

Glycated hemoglobin (HbA₁(c)), used to monitor and diagnose diabetes, is influenced by average glycemia over a 2- to 3-month period. Genetic factors affecting expression, turnover, and abnormal glycation of hemoglobin could also be associated with increased levels of HbA₁(c). We aimed to identify such genetic factors and investigate the extent to which they influence diabetes classification based on HbA₁(c) levels.

RESEARCH DESIGN AND METHODS

We studied associations with HbA₁(c) in up to 46,368 nondiabetic adults of European descent from 23 genome-wide association studies (GWAS) and 8 cohorts with de novo genotyped single nucleotide polymorphisms (SNPs). We combined studies using inverse-variance meta-analysis and tested mediation by glycemia using conditional analyses. We estimated the global effect of HbA₁(c) loci using a multilocus risk score, and used net reclassification to estimate genetic effects on diabetes screening.

RESULTS

Ten loci reached genome-wide significant association with HbA(1c), including six new loci near FN3K (lead SNP/P value, rs1046896/P = 1.6 × 10⁻²⁶), HFE (rs1800562/P = 2.6 × 10⁻²⁰), TMPRSS6 (rs855791/P = 2.7 × 10⁻¹⁴), ANK1 (rs4737009/P = 6.1 × 10⁻¹²), SPTA1 (rs2779116/P = 2.8 × 10⁻⁹) and ATP11A/TUBGCP3 (rs7998202/P = 5.2 × 10⁻⁹), and four known HbA₁(c) loci: HK1 (rs16926246/P = 3.1 × 10⁻⁵⁴), MTNR1B (rs1387153/P = 4.0 × 10⁻¹¹), GCK (rs1799884/P = 1.5 × 10⁻²⁰) and G6PC2/ABCB11 (rs552976/P = 8.2 × 10⁻¹⁸). We show that associations with HbA₁(c) are partly a function of hyperglycemia associated with 3 of the 10 loci (GCK, G6PC2 and MTNR1B). The seven nonglycemic loci accounted for a 0.19 (% HbA₁(c)) difference between the extreme 10% tails of the risk score, and would reclassify ∼2% of a general white population screened for diabetes with HbA₁(c).

CONCLUSIONS

GWAS identified 10 genetic loci reproducibly associated with HbA₁(c). Six are novel and seven map to loci where rarer variants cause hereditary anemias and iron storage disorders. Common variants at these loci likely influence HbA₁(c) levels via erythrocyte biology, and confer a small but detectable reclassification of diabetes diagnosis by HbA₁(c).

WWOX gene is associated with HDL cholesterol and triglyceride levels

Background

Altered lipid profile, and in particular low HDL and high triglyceride (TG) plasma levels, are within the major determinants of cardiovascular diseases. The identification of quantitative trait loci (QTL) affecting these lipid levels is a relevant issue for predictive purposes. The WWOX gene has been recently associated with HDL levels. This gene is located at chromosome 16q23, a region previously linked to familial combined hyperlipidemia (FCHL) and HDL. Our objective is to perform a genetic association analysis at the WWOX gene region with HDL, TG and TG/HDL ratio.

Methods

A quantitative association analysis performed in 801 individuals selected from the Spanish general population.

Results

For HDL levels, two regions of intron 8 display clustering of positive signals (p < 0.05) but none of them was associated in the haplotypic analysis (0.07 ≤ p ≤ 0.165). For TG levels not only intron 8 but also a 27 kb region spanning from the promoter region to intron 4 are associated in this study. For the TG/HDL genetic association analysis, positive signals are coincident with those of the isolated traits. Interestingly, haplotypic analysis at the 5' region showed that variation in this region modified both HDL and TG levels, especially the latter (p = 0.003).

Conclusions

Our results suggest that WWOX is a QTL for both TG and HDL.

Genetic structure of the Spanish population

BACKGROUND

Genetic admixture is a common caveat for genetic association analysis. Therefore, it is important to characterize the genetic structure of the population under study to control for this kind of potential bias.

RESULTS

In this study we have sampled over 800 unrelated individuals from the population of Spain, and have genotyped them with a genome-wide coverage. We have carried out linkage disequilibrium, haplotype, population structure and copy-number variation (CNV) analyses, and have compared these estimates of the Spanish population with existing data from similar efforts.

CONCLUSIONS

In general, the Spanish population is similar to the Western and Northern Europeans, but has a more diverse haplotypic structure. Moreover, the Spanish population is also largely homogeneous within itself, although patterns of micro-structure may be able to predict locations of origin from distant regions. Finally, we also present the first characterization of a CNV map of the Spanish population. These results and original data are made available to the scientific community.

A functional nonsynonymous toll-like receptor 4 gene polymorphism is associated with metabolic syndrome, surrogates of insulin resistance, and syndromes of lipid accumulation

Toll-like receptor 4 (TLR4) plays a key role in the activation of innate immune responses. Loss-of-function mutations in TLR4 prevent diet-induced obesity and insulin resistance (IR). We conducted a population cross-sectional study to evaluate whether Asp299Gly (rs4986790) TLR4 gene polymorphism is associated with metabolic syndrome (MS), surrogates of IR, and syndromes of lipid accumulation (SLAs) in Argentinean healthy male subjects. rs4986790 was genotyped in 621 healthy unrelated male blood donors. National Cholesterol Education Program/Adult Treatment Panel III-MS (NCEP/ATP III-MS); SLAs such as enlarged waist elevated triglyceride syndrome (EWET), hypertriglyceridemic waist (HW), and overweight-lipid syndrome (OLS); and surrogates of IR were assessed. The prevalence of MS, OLS, and EWET was significantly higher among Asp299Asp carriers (P < .05). These findings were confirmed using 32 000 bootstrap samples. Surrogate markers of IR were also significantly higher in Asp299Asp carriers (P < .05). Most findings were especially strengthened among individuals with C-reactive protein below the 95th percentile and/or total cholesterol to high-density lipoprotein cholesterol ratio >or=5. This is the first report to find, in Argentinean healthy male blood donors, associations between the Asp299Asp genotype of rs4986790 TLR4 gene polymorphism and high risk for NCEP/ATP III-MS, SLAs, and surrogates of IR. These findings are consistent with previous functional and observational studies showing that Asp299 allele, in comparison with Gly299, is associated with increased TLR4 activation, higher levels of inflammatory cytokines, acute-phase reactants and soluble adhesion molecules, and higher risk of atherosclerosis.

New genetic loci implicated in fasting glucose homeostasis and their impact on type 2 diabetes risk

Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, fasting insulin and indices of beta-cell function (HOMA-B) and insulin resistance (HOMA-IR) in up to 46,186 nondiabetic participants. Follow-up of 25 loci in up to 76,558 additional subjects identified 16 loci associated with fasting glucose and HOMA-B and two loci associated with fasting insulin and HOMA-IR. These include nine loci newly associated with fasting glucose (in or near ADCY5, MADD, ADRA2A, CRY2, FADS1, GLIS3, SLC2A2, PROX1 and C2CD4B) and one influencing fasting insulin and HOMA-IR (near IGF1). We also demonstrated association of ADCY5, PROX1, GCK, GCKR and DGKB-TMEM195 with type 2 diabetes. Within these loci, likely biological candidate genes influence signal transduction, cell proliferation, development, glucose-sensing and circadian regulation. Our results demonstrate that genetic studies of glycemic traits can identify type 2 diabetes risk loci, as well as loci containing gene variants that are associated with a modest elevation in glucose levels but are not associated with overt diabetes.

Variant rs9939609 in the FTO gene is associated with obesity in an adult population from Spain

OBJECTIVE

Recently independent studies, including genome-wide scans, have shown that variation in the fat mass and obesity associated gene (FTO) were significantly associated with obesity in populations of European origin.

DESIGN AND METHODS

In this study we examined the association between rs9939609 FTO variant and obesity related parameters in a population based-study of 732 unrelated individuals (46.9% males and 53.1% females; ages 35-74 years) from the province of Segovia in Central Spain (Castille).

RESULTS

The AA genotype was significantly more frequent in obese individuals (defined as body mass index >or= 30 kg/m(2), n = 207; 80 males and 127 females) than in non-obese (19.9%vs. 13.7%, P = 0.026). In addition to increased obesity, AA homozygous individuals had higher waist circumference than individuals with AT heterozygous and TT homozygous genotypes. The minor A-allele of rs9939609 was associated with an increased odds ratio (OR) for obesity [OR 1.51, 95% confidence interval (CI) 1.10-2.12] as compared to the TT genotype. This difference was also statistically significant even after the adjustment for sex and age (OR 1.46, 95% CI 1.02-2.07).

CONCLUSIONS

Our results support the association of FTO gene variants with obesity, including parameters of visceral (abdominal) obesity, in an adult general population from Spain. Overall we confirm the previously reported association studies between variants in FTO gene and the risk of obesity.

Association of variants of the TCF7L2 gene with increases in the risk of type 2 diabetes and the proinsulin:insulin ratio in the Spanish population

AIMS/HYPOTHESIS

The gene encoding transcription factor 7-like 2 (TCF7L2) has been related to type 2 diabetes in multiple ethnic groups. Here, we investigate whether three single nucleotide polymorphisms (SNPs) in the TCF7L2 gene are associated with an impaired proinsulin:insulin ratio.

METHODS

In this study we examined the associations between SNPs rs7901695, rs7903146 and rs12255372 in the TCF7L2 gene and metabolic variables affecting type 2 diabetes in a population-based study of 706 unrelated individuals (47% men and 53% women; aged 35-74 years) from the province of Segovia in central Spain (Castille), including 180 individuals with type 2 diabetes.

RESULTS

The minor allele frequency of rs7901695, rs7903146 and rs12255372 was significantly higher in diabetic patients compared with that in non-diabetic individuals. The T (minor) allele of the variant rs7903146 was significantly associated with a greater OR for type 2 diabetes adjusted for age, sex and BMI in logistic regression analysis: OR 1.29 (95% CI 1.06-1.57, p = 0.01). This risk allele was also associated with an increased proinsulin:insulin ratio after OGTT. Similar results were obtained for the other TCF7L2 SNPs.

CONCLUSIONS/INTERPRETATION

Our results provide further evidence supporting the belief that the TCF7L2 gene is a major determinant of type 2 diabetes risk in Spain, as in other southern European populations. The association with increased proinsulin:insulin ratio after an OGTT suggests that TCF7L2 might be involved in insulin synthesis and processing.

The FTO obesity gene. Genotyping and gene expression analysis in morbidly obese patients

BACKGROUND

Obesity has emerged as one of the most serious public health concerns in the twenty-first century. the fat mass and obesity associated gene (FTO) has been found to contribute to the risk of obesity in humans. Our aims in this study were to investigate the association of rs9939609 single nucleotide polymorphism (SNP) of the FTO gene with different obesity-related parameters, to assess the FTO gene expression in subcutaneous and visceral adipose tissues from morbidly obese and its correlations with other adipocytokine gene expressions.

METHODS

The association between the rs9939609 FTO gene variant and obesity related parameters in 75 obese/morbidly obese adult patients and 180 subjects with body mass index (BMI) < 30 kg/m(2) (control group) was examined. Gene expression analyses: subcutaneous adipose tissue samples were obtained from 52 morbidly obese and five subjects with BMI < 30 kg/m(2). Visceral adipose tissue was also obtained from 35 morbidly obese patients. Weight, height, BMI, SBP, DBP, fasting glucose, lipid profile, proinsulin, insulin, leptin, and adiponectin (RIA) of patients were also obtained. Insulin resistance by HOMA(IR). rs9939609 of FTO genotyping using allele discrimination in real-time PCR. Genomic study of RNA extraction of adipose tissue and real-time PCR (RT-PCR) of adipocytokines and a housekeeping gene were quantified using TaqMan probes. Relative quantification was calculated using the DeltaDelta Ct formula.

RESULTS

The minor-(A) allele frequency of rs9939609 FTO gene in the whole population was 0.39. A strong association between this A allele and obesity was found, even after age-sex adjustment (p = 0.013). We found higher levels of FTO mRNA in subcutaneous adipose tissue from morbidly obese than in the control group (p = 0.021). FTO gene expression was lower in visceral than in subcutaneous adipose depot. However, this finding did not reach the level of statistical significance. A negative correlation between subcutaneous FTO gene expression and serum triglyceride levels and a positive correlation with leptin, perilipin, and visfatin gene expressions was found. In the visceral adipose tissue, these positive correlations were statistically significant only for perilipin.

CONCLUSIONS

Our results show: (1) A strong association between rs9939609 SNP of the FTO gene variant and obesity in Spanish morbidly obese adult patients; (2) positive correlations between FTO mRNA and leptin, perilipin, and visfatin gene expressions in subcutaneous adipose tissue; (3) FTO and perilipin gene expressions were positively correlated in visceral fat depot. Overall these results may suggest a role of FTO in the regulation of lipolysis as well as in total body fat rather in fat distribution patterns.

The CAPN10 gene is associated with insulin resistance phenotypes in the Spanish population

Cardiovascular disease is the leading cause of morbidity and mortality in the industrialized world. Familial aggregation of cardiovascular risk factors is a frequent finding, but genetic factors affecting its presentation are still poorly understood. The calpain 10 gene (CAPN10) has been associated with type 2 diabetes (T2DM), a complex metabolic disorder with increased risk of cardiovascular disease. Moreover, the CAPN10 gene has been associated with the presence of metabolic syndrome (MS) in T2DM and in polycystic ovary syndrome (PCOS). In this work, we have analysed whether the polymorphisms UCSNP44, -43, -19 and -63 are related to several cardiovascular risk factors in the context of MS. Molecular analysis of CAPN10 gene was performed in 899 individuals randomly chosen from a cross-sectional population-based epidemiological survey. We have found that CAPN10 gene in our population is mainly associated with two indicators of the presence of insulin resistance: glucose levels two hours after a 75-g oral glucose tolerance test (OGTT) and HOMA values, although cholesterol levels and blood pressure values are also influenced by CAPN10 variants. In addition, the 1221/1121 haplogenotype is under-represented in individuals that fulfil the International Diabetes Federation (IDF) diagnostic criteria for MS. Our results suggest that CAPN10 gene is associated with insulin resistance phenotypes in the Spanish population.

Interaction between Calpain 5, Peroxisome proliferator-activated receptor-gamma and Peroxisome proliferator-activated receptor-delta genes: a polygenic approach to obesity

Context

Obesity is a multifactorial disorder, that is, a disease determined by the combined effect of genes and environment. In this context, polygenic approaches are needed.

Objective

To investigate the possibility of the existence of a crosstalk between the CALPAIN 10 homologue CALPAIN 5 and nuclear receptors of the peroxisome proliferator-activated receptors family.

Design

Cross-sectional, genetic association study and gene-gene interaction analysis.

Subjects

The study sample comprise 1953 individuals, 725 obese (defined as body mass index ≥ 30) and 1228 non obese subjects.

Results

In the monogenic analysis, only the peroxisome proliferator-activated receptor delta (PPARD) gene was associated with obesity (OR = 1.43 [1.04–1.97], p = 0.027). In addition, we have found a significant interaction between CAPN5 and PPARD genes (p = 0.038) that reduces the risk for obesity in a 55%.

Conclusion

Our results suggest that CAPN5 and PPARD gene products may also interact in vivo.

Association of ENPP1 (PC-1) K121Q polymorphism with obesity-related parameters in subjects with metabolic syndrome

BACKGROUND

The metabolic syndrome (MS), a cluster of several metabolic disorders, is increasingly being recognized as a risk factor for cardiovascular disease. Ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1), originally described as a plasma cell allo-antigen and named plasma cell membrane glycoprotein (PC-1), is an inhibitor of insulin-induced activation of the insulin receptor. The single nucleotide polymorphism (SNP) K121Q in the ENPP1 gene has been studied in relation to obesity, insulin resistance and other features of MS in several populations with conflicting results. We therefore investigate the role of the K121Q SNP in the ENPP1 gene in MS in Caucasians from the province of Segovia in Central Spain (Castille).

DESIGN AND METHODS

We recruited 794 unrelated persons (46.5% males and 53.5% females), ages 35-74 years from a cross-sectional population-based epidemiological survey in the province of Segovia in Central Spain (Castille). Obesity-related anthropometric measurements included BMI, waist circumference, blood pressure and lipid profile. MS was defined by International Diabetes Federation (IDF) guidelines. K121Q PC-1 genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

The 121Q allele was associated with an increased BMI and waist circumference among subjects fulfilling the criteria for MS. These differences remained statistically significant even after the adjustment for sex, age and degree of glucose tolerance (beta = 1.347, P = 0.017 and beta = 2.824, P = 0.046; for BMI and waist circumference, respectively). Moreover, among type 2 diabetic patients those carrying the 121Q allele had higher BMI and higher leptin levels than subjects carrying the K121K genotype.

CONCLUSIONS

Our results suggest that the ENPP1121Q allele might contribute to the genetic susceptibility to abdominal obesity among subjects with MS.

Molecular basis of insulin action

Insulin is the main anabolic and anticatabolic hormone in mammals. The stimulatory effect of insulin on glucose uptake in muscle and adipose tissue is a consequence of the rapid translocation of GLUT4 glucose transporters from an intracellular site to the cell surface. The actions of insulin are initiated by hormone binding to its cell surface receptors. Insulin receptors are ligand-stimulated protein tyrosine kinases and phosphorylate a number of proteins, known as insulin receptor substrate proteins. Insulin resistance has been recognized as a main pathogenic factor in the development of type 2 diabetes, and has been associated with dyslipidemia, hypertension, endothelial dysfunction, inflammation and coagulative state. The current challenge is the study of impaired insulin signaling pathways leading to beta-cell dysfunction and its progression to type 2 diabetes, as well as control of chronic inflammation processes that may improve insulin action.

Common haplotypes of the C-reactive protein gene and circulating leptin levels influence the interindividual variability in serum C-reactive protein levels. The Segovia study

C-reactive protein (CRP) is a marker of systemic inflammation significantly associated with an increased risk of cardiovascular disease in the general population. The aim of our current work was to study those clinical and genetic variables potentially associated with interindividual variability in serum CRP levels. A random sample of 844 participants (450 women, mean age 55 years) from a study carried out on the general Spanish population (The Segovia Study) was studied. Our results showed that age, gender, waist circumference, leptin, impaired glucose tolerance and smoking were the clinical variables significantly associated with variations in serum CRP levels. Among those, leptin showed the strongest association, explaining 11% of the interindividual variability in circulating CRP levels (p<0.001). To study the effect of genetic variants on serum CRP levels, 10 SNPs within the CRP locus were genotyped in 756 participants. Four of these SNPs (rs1417938, rs1800947, rs1130864, rs1205) were significantly associated with CRP levels after adjustment for clinical variables. Among the common haplotypes inferred from eight SNPs, two (CCATGCCT, p=0.025; CTATCCTT, p=0.004) explained 2.9% of the total variation in serum CRP. The results here reported show that 2.9% of the total variation in circulating CRP levels seems to be explained by genetics variations within CRP locus. Furthermore, serum leptin levels are strongly associated with serum CRP levels in our Spanish population.

Which obesity index best explains prevalence differences in type 2 diabetes mellitus?

OBJECTIVE

Obesity drives the diabetes epidemic. However, it is not known which obesity index best explains variations in type 2 diabetes mellitus prevalence across populations.

RESEARCH METHODS AND PROCEDURES

We analyzed three cross-sectional studies from San Antonio, TX, (Mexican-Americans and non-Hispanic whites, n = 2839), Mexico City (n = 2233), and Spain (n = 2161) (age range, 35 to 64 years). We used the area under the receiver operating characteristic curve (AUC) to assess performance for identifying diabetic subjects and logistic regression analysis to examine differences in diabetes prevalence.

RESULTS

AUCs for waist circumference and BMI were similar in white subjects, but the AUC for waist circumference was greater in Mexican-origin subjects (Mexican men, 0.594 vs. 0.549, p = 0.008; and women, 0.605 vs. 0.557, p = 0.002; Mexican-American men, 0.648 vs. 0.600, p < 0.001; and women, 0.744 vs. 0.693, p < 0.001). The AUC for waist-to-height ratio tended to be greater than that for waist circumference, but statistical significance was demonstrated only in Mexican women (0.628 vs. 0.613, p = 0.044), Mexican-American women (0.774 vs. 0.758, p < 0.001), and Spanish women (0.734 vs. 0.715, p = 0.039). No obesity index was consistently superior to the others for explaining differences in diabetes prevalence among populations.

CONCLUSIONS

In white and Mexican-origin men, waist circumference may be the preferred marker for identifying diabetic subjects on account of its simplicity; in women, waist-to-height ratio may be better. Differences in diabetes prevalence among these populations cannot be attributed to a single measure of obesity.

Is the plasminogen activator inhibitor-1 gene a candidate gene predisposing to hypertension? Results from a population-based study in Spain

BACKGROUND

Studies in humans and mice suggest that plasminogen activator inhibitor-1 (PAI-1) might be a candidate gene for arterial hypertension. Our aims were to analyse whether the functional 4G/5G PAI-1 polymorphism represents a risk marker for the development of arterial hypertension regardless of hypertension-related metabolic variables.

METHODS

Eight hundred and fifteen unrelated individuals (387 men, age 35-74 years) from a cross-sectional, population-based, epidemiological survey in the province of Segovia (Spain) were studied. Anthropometric/biochemical parameters--body mass index, waist circumference, diastolic and systolic blood pressures, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, fasting glucose, insulin, C-reactive protein, and PAI-1 levels--were analysed. The 4G/5G PAI-1 genotypes were established by restriction fragment length polymorphism. Insulin resistance was estimated by the homeostasis model assessment. Tobacco consumption data were obtained using a standard questionnaire.

RESULTS

The 4G/4G PAI-1 genotype was significantly associated with a high prevalence of arterial hypertension. This association remained statistically significant even after adjustment for hypertension-related metabolic variables in our population (adjusted odds ratio, 1.858; 95% confidence interval, 1.135-3.018; P = 0.013).

CONCLUSION

Our results show that the 4G/4G PAI-1 genotype appears to be associated with an elevated relative risk of developing arterial hypertension, regardless of PAI-1 levels and other hypertension-related factors, in a representative sample of the Spanish population.

Calpain-5 gene variants are associated with diastolic blood pressure and cholesterol levels

Background

Genes implicated in common complex disorders such as obesity, type 2 diabetes mellitus (T2DM) or cardiovascular diseases are not disease specific, since clinically related disorders also share genetic components. Cysteine protease Calpain 10 (CAPN10) has been associated with T2DM, hypertension, hypercholesterolemia, increased body mass index (BMI) and polycystic ovary syndrome (PCOS), a reproductive disorder of women in which isunlin resistance seems to play a pathogenic role. The calpain 5 gene (CAPN5) encodes a protein homologue of CAPN10. CAPN5 has been previously associated with PCOS by our group. In this new study, we have analysed the association of four CAPN5 gene variants(rs948976A>G, rs4945140G>A, rs2233546C>T and rs2233549G>A) with several cardiovascular risk factors related to metabolic syndrome in general population.

Methods

Anthropometric measurements, blood pressure, insulin, glucose and lipid profiles were determined in 606 individuals randomly chosen from a cross-sectional population-based epidemiological survey in the province of Segovia in Central Spain (Castille), recruited to investigate the prevalence of anthropometric and physiological parameters related to obesity and other components of the metabolic syndrome. Genotypes at the four polymorphic loci in CAPN5 gene were detected by polymerase chain reaction (PCR).

Results

Genotype association analysis was significant for BMI (p ≤ 0.041), diastolic blood pressure (p = 0.015) and HDL-cholesterol levels (p = 0.025). Different CAPN5 haplotypes were also associated with diastolic blood pressure (DBP) (0.0005 ≤ p ≤ 0.006) and total cholesterol levels (0.001 ≤ p ≤ 0.029). In addition, the AACA haplotype, over-represented in obese individuals, is also more frequent in individuals with metabolic syndrome defined by ATPIII criteria (p = 0.029).

Conclusion

As its homologue CAPN10, CAPN5 seems to influence traits related to increased risk for cardiovascular diseases. Our results also may suggest CAPN5 as a candidate gene for metabolic syndrome.