The role of working conditions in educational differences in all-cause and ischemic heart disease mortality among Swedish men.

OBJECTIVES: This study aims to investigate the extent to which low job control and heavy physical workload in middle age explain educational differences in all-cause and ischemic heart disease (IHD) mortality while accounting for important confounding factors. METHODS: The study is based on a register-linked cohort of men who were conscripted into the Swedish military at around the age of 18 in 1969/1970 and were alive and registered in Sweden in 2005 (N=46 565). Cox proportional hazards regression models were built to estimate educational differences in all-cause and IHD mortality and the extent to which this was explained by physical workload and job control around age 55 by calculating the reduction in hazard ratio (HR) after adjustments. Indicators of health, health behavior, and other factors measured during conscription were accounted for. RESULTS: We found a clear educational gradient for all-cause and IHD mortality (HR 2.07 and 2.47, respectively, for the lowest compared to the highest education level). A substantial part was explained by the differential distribution of the confounding factors. However, work-related factors, especially high physical workload, also played important explanatory roles. CONCLUSION: Even after accounting for earlier life factors, low job control and especially high physical workload seem to be important mechanistic factors in explaining educational inequalities in all-cause and IHD mortality. It is therefore important to find ways to reduce physical workload and increase job control in order to decrease inequalities in mortality.

Do early life factors explain the educational differences in early labour market exit? A register-based cohort study.

BACKGROUND: Socioeconomic inequalities in labour market participation are well established. However, we do not fully know what causes these inequalities. The present study aims to examine to what extent factors in childhood and late adolescence can explain educational differences in early labour market exit among older workers. METHODS: All men born in 1951-1953 who underwent conscription examination for the Swedish military in 1969-1973 (n = 145 551) were followed from 50 to 64 years of age regarding early labour market exit (disability pension, long-term sickness absence, long-term unemployment and early old-age retirement with and without income). Early life factors, such as cognitive ability, stress resilience, and parental socioeconomic position, were included. Cox proportional-hazards regressions were used to estimate the association between the level of education and each early labour market exit pathway, including adjustment for early life factors. RESULTS: The lowest educated men had a higher risk of exit through disability pension (HR: 2.72), long-term sickness absence (HR: 2.29), long-term unemployment (HR: 1.45), and early old-age retirement with (HR: 1.29) and without income (HR: 1.55) compared to the highest educated men. Factors from early life explained a large part of the educational differences in disability pension, long-term sickness absence and long-term unemployment but not for early old-age retirement. Important explanatory factors were cognitive ability and stress resilience, whilst cardiorespiratory fitness had negligible impact. CONCLUSIONS: The association between education and early exit due to disability pension, long-term sickness absence and long-term unemployment was to a large part explained by factors from early life. However, this was not seen for early old-age retirement. These results indicate the importance of taking a life-course perspective when examining labour market participation in later working life.

Resting Level of Insulin-Like Growth Factor-1 Is Not at Play in Cardiac Enlargement in Endurance-Trained Adolescents.

PURPOSE: The study aimed to investigate resting levels of several selected growth and metabolic hormones in a group of 24 endurance-trained adolescents (aged 13-19 years) compared with 24 untrained age- and sex-matched controls, and to investigate if increased cardiac dimensions were related to these hormones at rest with emphasis on insulin-like growth factor-1 (IGF-1). METHODS: The hormones (cortisol, IGF-1, IGF-2, follicle-stimulating hormone, growth hormone, luteinizing hormone, prolactin, and thyroid-stimulating hormone) were analysed with chemiluminescence microparticle immunoassay (CMIA) or multiplex fluorochrome (Luminex) technique. Cardiac dimensions were assessed by echocardiographic examination at rest. Peak oxygen uptake was obtained by a maximal cardiopulmonary exercise test on a treadmill. RESULTS: Circulating levels of analysed hormones at rest did not differ between the groups. A correlation was found between increased cardiac dimensions and IGF-1 in the controls, but not in the active group. This correlation declined also among the controls when the cardiac parameters were indexed for body surface area. CONCLUSION: Increased cardiac dimensions in endurance-trained adolescents could not be related to resting levels of hormones associated with growth and metabolism, including IGF-1 and GH. In addition, the resting levels of these hormones seem not to be affected by intense regular endurance exercise in adolescents. These findings may contribute to the knowledge about cellular signaling that trigger growth as well as cardiac adaptation to endurance training in young athletes.

Swedish patients' trust in the bioequivalence of interchangeable generics. What factors are important for low trust?

Background: Generic substitution (GS), is a cost-containment strategy meant to contain pharmaceutical expenditure without compromising health objectives. In order to shape GS into a policy that is both efficient and safe it is crucial to understand which factors are most important for patients' trust in GS. Objective: To assess Swedish patients' level of trust in the bioequivalence of cheap and expensive generic medicines, and the association between trust and various factors. Methods: A cross-sectional study was conducted. Questionnaires were handed out at 12 community pharmacies in Sweden, selected through stratified sampling, between March and April 2015. The questionnaire included seven socio-demographic questions in addition to 18 items divided into three sections: the 'views on generic medicine'-scale, information on and prior experiences of GS, financial aspects and change of color/name. Odds Ratios (ORs) were estimated applying adjusted logistic regression analyses with trust in the bioequivalence of generic medicines used as outcome variable and various factors as predictors. Results: A total of 719 patients participated (response rate 85.7%). The results show that 70.7% of the respondents' trust that cheap and expensive interchangeable generic medicines are equal. Of the respondents 36.0% considered the change in appearance and 40.8% the change in names to complicate adherence. Lower trust in the bioequivalence of generic medicines were associated with being female (aOR=1.82, 95%CI 1.20:2.75, p<0.01), patients perceiving that changes in product name and appearance make adherence more complicated (aOR=2.18, 95%CI 1.48:3.19, p<0.001), disagreeing in that GS saves money for me (the customer) (aOR=2.68, 95%CI 1.58:4.55, p<0.001) or that GS saves money for society (aOR=3.21, 95%CI 1.46:7.08, p<0.01). Conclusions: Seven out of ten respondents had trust in the bioequivalence of generic medicines, and one in three considered GS to complicate adherence. Four factors were associated with lower trust in GS, i.e. female gender, agreeing that changes in product name and appearance complicates adherence, disagreeing in that GS saves money for me or disagreeing in that GS saves money for the society. Low trust in GS needs to be addressed, not least in the communication between health professionals and patients

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Swedish patients' trust in the bioequivalence of interchangeable generics. What factors are important for low trust?

BACKGROUND: Generic substitution (GS), is a cost-containment strategy meant to contain pharmaceutical expenditure without compromising health objectives. In order to shape GS into a policy that is both efficient and safe it is crucial to understand which factors are most important for patients' trust in GS. OBJECTIVE: To assess Swedish patients' level of trust in the bioequivalence of cheap and expensive generic medicines, and the association between trust and various factors. METHODS: A cross-sectional study was conducted. Questionnaires were handed out at 12 community pharmacies in Sweden, selected through stratified sampling, between March and April 2015. The questionnaire included seven socio-demographic questions in addition to 18 items divided into three sections: the 'views on generic medicine'-scale, information on and prior experiences of GS, financial aspects and change of color/name. Odds Ratios (ORs) were estimated applying adjusted logistic regression analyses with trust in the bioequivalence of generic medicines used as outcome variable and various factors as predictors. RESULTS: A total of 719 patients participated (response rate 85.7%). The results show that 70.7% of the respondents' trust that cheap and expensive interchangeable generic medicines are equal. Of the respondents 36.0% considered the change in appearance and 40.8% the change in names to complicate adherence. Lower trust in the bioequivalence of generic medicines were associated with being female (aOR=1.82, 95%CI 1.20:2.75, p<0.01), patients perceiving that changes in product name and appearance make adherence more complicated (aOR=2.18, 95%CI 1.48:3.19, p<0.001), disagreeing in that GS saves money for me (the customer) (aOR=2.68, 95%CI 1.58:4.55, p<0.001) or that GS saves money for society (aOR=3.21, 95%CI 1.46:7.08, p<0.01). CONCLUSIONS: Seven out of ten respondents had trust in the bioequivalence of generic medicines, and one in three considered GS to complicate adherence. Four factors were associated with lower trust in GS, i.e. female gender, agreeing that changes in product name and appearance complicates adherence, disagreeing in that GS saves money for me or disagreeing in that GS saves money for the society. Low trust in GS needs to be addressed, not least in the communication between health professionals and patients.

Regular endurance training in adolescents impacts atrial and ventricular size and function.

AIMS: The aims of the study were to explore the effects of long-term endurance exercise on atrial and ventricular size and function in adolescents and to examine whether these changes are related to maximal oxygen uptake (VO2max). METHODS AND RESULTS: Twenty-seven long-term endurance-trained adolescents aged 13-19 years were individually matched by age and gender with 27 controls. All participants, 22 girls and 32 boys, underwent an echocardiographic examination at rest, including standard and colour tissue Doppler investigation. VO2max was assessed during treadmill exercise. All heart dimensions indexed for body size were larger in the physically active group compared with controls: left ventricular end-diastolic volume 60 vs. 50 mL/m2 (P <0.001), left atrial volume 27 vs. 19 mL/m2 (P < 0.001), and right ventricular (RV) and right atrial area 15 vs. 13 and 9 vs. 7 cm2/m2, respectively (P <0.001 for both). There were strong associations between the size of the cardiac chambers and VO2max. Further, we found improved systolic function in the active group compared with controls: left ventricular ejection fraction 61 vs. 59% (P= 0.036), tricuspid annular plane systolic excursion 12 vs. 10 mm/m2 (P= 0.008), and RV early peak systolic velocity s' 11 vs. 10 cm/s (P = 0.031). CONCLUSION: Cardiac remodelling to long-term endurance exercise in adolescents is manifested by an increase in atrial as well as ventricular dimensions. The physically active group also demonstrated functional remodelling with an increase in TAPSE and systolic RV wall velocity. These findings have practical implications when assessing cardiac enlargement and function in physically active youngsters.

Psychological stress in children may alter the immune response.

Psychological stress is a public health issue even in children and has been associated with a number of immunological diseases. The aim of this study was to examine the relationship between psychological stress and immune response in healthy children, with special focus on autoimmunity. In this study, psychological stress was based on a composite measure of stress in the family across the domains: 1) serious life events, 2) parenting stress, 3) lack of social support, and 4) parental worries. PBMCs, collected from 5-y-old high-stressed children (n = 26) and from 5-y-old children without high stress within the family (n = 52), from the All Babies In Southeast Sweden cohort, were stimulated with Ags (tetanus toxoid and ß-lactoglobulin) and diabetes-related autoantigens (glutamic acid decarboxylase 65, insulin, heat shock protein 60, and tyrosine phosphatase). Immune markers (cytokines and chemokines), clinical parameters (C-peptide, proinsulin, glucose), and cortisol, as an indicator of stress, were analyzed. Children from families with high psychological stress showed a low spontaneous immune activity (IL-5, IL-10, IL-13, IL-17, CCL2, CCL3, and CXCL10; p < 0.01) but an increased immune response to tetanus toxoid, ß-lactoglobulin, and the autoantigens glutamic acid decarboxylase 65, heat shock protein 60, and tyrosine phosphatase (IL-5, IL-6, IL-10, IL-13, IL-17, IFN-γ, TNF-α, CCL2, CCL3, and CXCL10; p < 0.05). Children within the high-stress group showed high level of cortisol, but low level of C-peptide, compared with the control group (p < 0.05). This supports the hypothesis that psychological stress may contribute to an imbalance in the immune response but also to a pathological effect on the insulin-producing ß cells.

TXNIP regulates peripheral glucose metabolism in humans.

BACKGROUND: Type 2 diabetes mellitus (T2DM) is characterized by defects in insulin secretion and action. Impaired glucose uptake in skeletal muscle is believed to be one of the earliest features in the natural history of T2DM, although underlying mechanisms remain obscure. METHODS AND FINDINGS: We combined human insulin/glucose clamp physiological studies with genome-wide expression profiling to identify thioredoxin interacting protein (TXNIP) as a gene whose expression is powerfully suppressed by insulin yet stimulated by glucose. In healthy individuals, its expression was inversely correlated to total body measures of glucose uptake. Forced expression of TXNIP in cultured adipocytes significantly reduced glucose uptake, while silencing with RNA interference in adipocytes and in skeletal muscle enhanced glucose uptake, confirming that the gene product is also a regulator of glucose uptake. TXNIP expression is consistently elevated in the muscle of prediabetics and diabetics, although in a panel of 4,450 Scandinavian individuals, we found no evidence for association between common genetic variation in the TXNIP gene and T2DM. CONCLUSIONS: TXNIP regulates both insulin-dependent and insulin-independent pathways of glucose uptake in human skeletal muscle. Combined with recent studies that have implicated TXNIP in pancreatic beta-cell glucose toxicity, our data suggest that TXNIP might play a key role in defective glucose homeostasis preceding overt T2DM.

Variation in the adiponutrin gene influences its expression and associates with obesity.

Adiponutrin is one of three recently identified adipocyte lipases. Surprisingly, these proteins also retain transacylase activity, a hitherto unknown pathway of triacylglycerol synthesis in the adipocytes. This may enable them to participate in both anabolic and catabolic processes. The adiponutrin gene (ADPN) is downregulated by fasting and upregulated by refeeding, suggesting a role in lipogenesis. Experiments in human adipocytes confirmed that the gene is upregulated in response to insulin in a glucose-dependent fashion. Obese subjects had increased levels of subcutaneous and visceral abdominal adipose tissue ADPN mRNA. Visceral ADPN mRNA expression was correlated to measures of insulin sensitivity (fasting insulin and homeostasis model assessment). We also studied genetic variation in ADPN and its relation to obesity, lipolysis, and mRNA expression. Two ADPN polymorphisms showed association with obesity. Carriers of the obesity-associated variants showed a lesser increase in the levels of adipose tissue ADPN mRNA and an increased basal lipolysis. Our results suggest that obese subjects that are insulin resistant and/or carriers of the obesity-associated ADPN alleles fail to upregulate the gene and that upregulation of adiponutrin may be an appropriate response to orchestrate energy excess.

Genetic and nongenetic regulation of CAPN10 mRNA expression in skeletal muscle.

The gene encoding calpain-10 (CAPN10) has been identified as a candidate gene for type 2 diabetes. Our aim was to study the impact of genetic (heritability and polymorphisms) and nongenetic (insulin, free fatty acids, and age) factors on CAPN10 mRNA expression in skeletal muscle using two different study designs. Muscle biopsies were obtained before and after hyperinsulinemic-euglycemic clamps from 166 young and elderly monozygotic and dizygotic twins as well as from 15 subjects with normal (NGT) or impaired glucose tolerance (IGT) exposed to an Intralipid infusion. We found hereditary effects on both basal and insulin-exposed CAPN10 mRNA expression. Carriers of the type 2 diabetes-associated single nucleotide polymorphism (SNP)-43 G/G genotype had reduced CAPN10 mRNA levels compared with subjects carrying the SNP-43 A-allele. Age had no significant influence on CAPN10 mRNA levels. Insulin had no significant effect on CAPN10 mRNA levels, neither in the twins nor in the basal state of the Intralipid study. However, after a 24-h infusion of Intralipid, we noted a significant increase in CAPN10 mRNA in response to insulin in subjects with NGT but not in subjects with IGT. In conclusion, we provide evidence that mRNA expression of CAPN10 in skeletal muscle is under genetic control. Glucose-tolerant but not glucose-intolerant individuals upregulate their CAPN10 mRNA levels in response to prolonged exposure to fat.

Epigenetic differences arise during the lifetime of monozygotic twins.

Monozygous twins share a common genotype. However, most monozygotic twin pairs are not identical; several types of phenotypic discordance may be observed, such as differences in susceptibilities to disease and a wide range of anthropomorphic features. There are several possible explanations for these observations, but one is the existence of epigenetic differences. To address this issue, we examined the global and locus-specific differences in DNA methylation and histone acetylation of a large cohort of monozygotic twins. We found that, although twins are epigenetically indistinguishable during the early years of life, older monozygous twins exhibited remarkable differences in their overall content and genomic distribution of 5-methylcytosine DNA and histone acetylation, affecting their gene-expression portrait. These findings indicate how an appreciation of epigenetics is missing from our understanding of how different phenotypes can be originated from the same genotype.

The FOXC2 C-512T polymorphism is associated with obesity and dyslipidemia.

The transcription factor FOXC2 has been implicated in resistance to diet-induced obesity and insulin resistance. To investigate the possible role for FOXC2 in obesity and related phenotypes, we performed two association studies for obesity using unrelated case-control materials by genotyping the FOXC2 C-512T polymorphism. In the first study (127 obese and 127 normal-weight nondiabetic subjects matched for age and sex), the C-allele showed association with obesity, odds ratio 1.74 (1.12 to 2.73; p < 0.01) for the C- vs. T-allele and 1.81 (1.04 to 3.25; p < 0.05) for the C/C and C/T vs. T/T genotype. BMI was higher in carriers of the C/C and C/T genotype in normal weight [adjusted p value (p(adj)) = 0.02] but not in obese subjects (p(adj) = 0.1). In the replication study (223 obese and 231 nonobese subjects), subjects with the C/C genotype exhibited an increased risk for obesity, odds ratio 2.01 (1.15 to 3.52; p = 0.01). Obese carriers of the C-allele had lower high-density lipoprotein-cholesterol [1.1 (0.9 to 1.3) vs. 1.2 (1.0 to 1.4) mM, p(adj) = 0.006] and increased triglyceride levels (1.95 [1.30 to 2.68] vs. 1.60 [1.10 to 2.40] mM, p(adj) = 0.02) compared with obese carriers of the T/T genotype. Our data suggest that FOXC2 is a weak but consistent candidate gene for obesity and dyslipidemia.

Multiple environmental and genetic factors influence skeletal muscle PGC-1alpha and PGC-1beta gene expression in twins.

Genetic and environmental factors contribute to age-dependent susceptibility to type 2 diabetes. Recent studies have reported reduced expression of PPARgamma coactivator 1alpha (PGC-1alpha) and PGC-1beta genes in skeletal muscle from type 2 diabetic patients, but it is not known whether this is an inherited or acquired defect. To address this question we studied expression of these genes in muscle biopsies obtained from young and elderly dizygotic and monozygotic twins without known diabetes before and after insulin stimulation and related the expression to a Gly482Ser variant in the PGC-1alpha gene. Insulin increased and aging reduced skeletal muscle PGC-1alpha and PGC-1beta mRNA levels. This age-dependent decrease in muscle gene expression was partially heritable and influenced by the PGC-1alpha Gly482Ser polymorphism. In addition, sex, birth weight, and aerobic capacity influenced expression of PGC-1alpha in a complex fashion. Whereas expression of PGC-1alpha in muscle was positively related to insulin-stimulated glucose uptake and oxidation, PGC-1beta expression was positively related to fat oxidation and nonoxidative glucose metabolism. We conclude that skeletal muscle PGC-1alpha and PGC-1beta expression are stimulated by insulin and reduced by aging. The data also suggest different regulatory functions for PGC-1alpha and PGC-1beta on glucose and fat oxidation in muscle cells. The finding that the age-dependent decrease in the expression of these key genes regulating oxidative phosphorylation is under genetic control could provide an explanation by which an environmental trigger (age) modifies genetic susceptibility to type 2 diabetes.

Variation in the calpain-10 gene is associated with elevated triglyceride levels and reduced adipose tissue messenger ribonucleic acid expression in obese Swedish subjects.

Our aim was to investigate the possible role of the type 2 diabetes susceptibility gene CAPN10 in obesity. A case control study consisting of 235 obese Swedish subjects [body mass index, 40 (35-45) kg/m(2)] and 235 controls matched for age and gender [body mass index, 22 (21-24) kg/m(2)], and a transmission disequilibrium test consisting of 116 parents-offspring trios, where the offspring was abdominally obese [waist, 100 (95-110) cm], were performed. CAPN10 mRNA expression was studied in adipose tissue biopsies from 33 of the obese subjects participating in the case control study. The CAPN10 single-nucleotide polymorphism (SNP)-43 was genotyped using PCR followed by NdeI digestion or by allelic discrimination. CAPN10 mRNA levels were quantified using real-time RT-PCR with Cyclophilin A as an internal standard. No significant associations between CAPN10 SNP-43 and obesity were seen, neither in the case control study nor in the transmission disequilibrium test, but obese subjects homozygous for the SNP-43 G allele had significantly elevated triglyceride levels compared with subjects carrying the A allele [1.7 (1.1-2.4) vs. 1.4 (1.0-2.0); P = 0.03]. The CAPN10 mRNA expression in sc fat was significantly reduced in subjects with the SNP-43 G/G genotype compared with carriers of SNP-43 G/A (G/G, 0.33 +/- 0.02, vs. G/A, 0.51 +/- 0.09; P = 0.048), and a similar trend was observed in visceral fat (G/G, 0.52 +/- 0.06, vs. G/A, 0.65 +/- 0.10; P = 0.22). Our data suggest that reduced CAPN10 expression may be a risk factor for features associated with the metabolic syndrome in obese subjects, although variation in the gene does not seem to contribute to the risk for developing obesity per se.

Impaired cathepsin L gene expression in skeletal muscle is associated with type 2 diabetes.

To identify abnormally expressed genes associated with muscle insulin resistance or type 2 diabetes, we screened the mRNA populations using cDNA differential display combined with relative RT-PCR analysis from muscle biopsies of diabetes-prone C57BL/6J and diabetes-resistant NMRI mice fed with a high-fat or normal diet for 3 or 15 months. Six abnormally expressed genes were isolated from the mice after a 3-month fat feeding; one of them was cathepsin L. No significant difference in mRNA levels of these genes was observed between fat- and normal-diet conditions in either strains. However, cathepsin L mRNA levels in muscle were higher in normal diet-fed C57BL/6J mice compared with normal diet-fed NMRI mice at 3 months (0.72 +/- 0.04 vs. 0.51 +/- 0.04 relative units, P < 0.01, n = 8-10) and at 15 months (0.41 +/- 0.05 vs. 0.27 +/- 0.04 relative units, P = 0.01, n = 9-10). Further, cathepsin L mRNA levels in muscle correlated inversely with plasma glucose in both strains regardless of diets at 3 (r = -0.49, P < 0.01, n = 31) and 15 (r = -0.42, P = 0.007, n = 39) months. To study whether cathepsin L plays a role in human diabetes, we measured cathepsin L mRNA levels in muscle biopsies taken before and after an insulin clamp from 12 monozygotic twin pairs discordant for type 2 diabetes and from 12 control subjects. Basal cathepsin L mRNA levels were not significantly different between the study groups. Insulin infusion increased cathepsin L mRNA levels in control subjects from 1.03 +/- 0.30 to 1.90 +/- 0.32 relative units (P = 0.03). Postclamp cathepsin L mRNA levels were lower in diabetic twins but similar in nondiabetic twins compared with control subjects (0.66 +/- 0.22, 1.16 +/- 0.18 vs. 1.38 +/- 0.21 relative units, P < 0.02, NS, respectively). Further, postclamp cathepsin L mRNA levels were correlated with insulin-mediated glucose uptake (r = 0.37, P = 0.03), particularly, with glucose oxidation (r = 0.37, P = 0.03), and fasting glucose concentrations (r = -0.45, P < 0.01) across all three study groups. In conclusion, muscle cathepsin L gene expression is increased in diabetes-prone mice and related to glucose tolerance. In humans, insulin-stimulated cathepsin L expression in skeletal muscle is impaired in diabetic but not in nondiabetic monozygotic twins, suggesting that the changes may be secondary to impaired glucose metabolism.

PGC-1alpha-responsive genes involved in oxidative phosphorylation are coordinately downregulated in human diabetes.

DNA microarrays can be used to identify gene expression changes characteristic of human disease. This is challenging, however, when relevant differences are subtle at the level of individual genes. We introduce an analytical strategy, Gene Set Enrichment Analysis, designed to detect modest but coordinate changes in the expression of groups of functionally related genes. Using this approach, we identify a set of genes involved in oxidative phosphorylation whose expression is coordinately decreased in human diabetic muscle. Expression of these genes is high at sites of insulin-mediated glucose disposal, activated by PGC-1alpha and correlated with total-body aerobic capacity. Our results associate this gene set with clinically important variation in human metabolism and illustrate the value of pathway relationships in the analysis of genomic profiling experiments.

FOXC2 mRNA Expression and a 5' untranslated region polymorphism of the gene are associated with insulin resistance.

The human transcription factor FOXC2 has recently been shown to protect against diet-induced insulin resistance in transgenic mice. We investigated the expression of FOXC2 in fat and muscle and performed a genetic analysis in human subjects. FOXC2 mRNA levels were increased in visceral compared with subcutaneous fat from obese subjects (12 +/- 4-fold; P = 0.0001), and there was a correlation between whole-body insulin sensitivity and FOXC2 mRNA levels in visceral fat (fS-insulin R = -0.64, P = 0.01, and homeostasis model assessment of insulin resistance [HOMA-IR] R = -0.68, P = 0.007) and skeletal muscle (fS-insulin R = -0.57, P = 0.03, and HOMA-IR R = -0.55, P = 0.04). Mutation screening of the FOXC2 gene identified a common polymorphism in the 5' untranslated region (C-512T). The T allele was associated with enhanced insulin sensitivity (HOMA-IR P = 0.007) and lower plasma triglyceride levels in females (P = 0.007). Also, the higher expression of FOXC2 in visceral than in subcutaneous fat was restricted to subjects homozygous for the T allele (P = 0.03 vs. P = 0.7). Our data suggest that increased FOXC2 expression may protect against insulin resistance in human subjects and that genetic variability in the gene may influence features associated with the metabolic syndrome.