Depressive symptoms and insulin resistance in young adult males: results from the Northern Finland 1966 birth cohort

The association between insulin resistance and depressive symptoms - A national representative cross-sectional study

OBJECTIVE

Increasing evidence suggests a positive association between insulin resistance (IR) and depression. However, whether sex-or body mass index-specific differences exist remains controversial, and only few studies have analyzed specific symptom domains. Thus, the present study aimed to analyze the association between IR and depressive symptom domains and to clarify the effects of sex and body mass index.

METHODS

The study sample comprised 4007 participants, aged 19-79, from the Korea National Health and Nutrition Examination Study 2020. Participants completed health interviews and examinations, providing data on circulating insulin and glucose levels, the Patient Health Questionnaire-9 (PHQ-9), and related covariates. IR was calculated using the homeostasis model assessment of insulin resistance. Associations between IR and PHQ-9 were analyzed using negative binomial regression with adjustments for the complex survey design.

RESULTS

The association between log-transformed IR and PHQ-9 total scores was statistically significant (incidence rate ratio [IRR] = 1.17, 95% confidence interval [CI] = 1.07-1.29, p = 0.001). Only body mass index specific differences were statistically significant, as the association was only significant in those without obesity (IRR = 1.21, 95% CI = 1.06-1.38, p = 0.005). IR was associated with cognitive/affective (IRR = 1.23, 95% CI = 1.08-1.41, p = 0.002) and somatic (IRR = 1.14, 95% CI = 1.04-1.25, p = 0.005) depressive symptom domains. Sensitivity analyses revealed similar results.

CONCLUSIONS

IR was positively associated with cognitive/affective and somatic depressive symptoms in non-obese individuals.

Significance of Brain Glucose Hypometabolism, Altered Insulin Signal Transduction, and Insulin Resistance in Several Neurological Diseases

Several neurological diseases share pathological alterations, even though they differ in their etiology. Neuroinflammation, altered brain glucose metabolism, oxidative stress, mitochondrial dysfunction and amyloidosis are biological events found in those neurological disorders. Altered insulin-mediated signaling and brain glucose hypometabolism are characteristic signs observed in the brains of patients with certain neurological diseases, but also others such as type 2 diabetes mellitus and vascular diseases. Thus, significant reductions in insulin receptor autophosphorylation and Akt kinase activity, and increased GSK-3 activity and insulin resistance, have been reported in these neurological diseases as contributing to the decline in cognitive function. Supporting this relationship is the fact that nasal and hippocampal insulin administration has been found to improve cognitive function. Additionally, brain glucose hypometabolism precedes the unmistakable clinical manifestations of some of these diseases by years, which may become a useful early biomarker. Deficiencies in the major pathways of oxidative energy metabolism have been reported in patients with several of these neurological diseases, which supports the hypothesis of their metabolic background. This review remarks on the significance of insulin and brain glucose metabolism alterations as keystone common pathogenic substrates for certain neurological diseases, highlighting new potential targets.

Cardiovascular risk factors and major depressive disorder: a cross-sectional study in São Paulo, Brazil

BACKGROUND

Cardiovascular risk factors can mediate the association between depression and cardiovascular diseases.

OBJECTIVE

To evaluate cardiovascular risk factors in adult individuals with and without histories of major depression in the metropolitan region of São Paulo, Brazil.

DESIGN AND SETTING

Cross-sectional study in São Paulo (SP), Brazil.

METHODS

This study evaluated 423 individuals without any lifetime diagnosis of major depression and 203 individuals with a previous diagnosis of major depression (n = 626). The participants underwent a psychiatric evaluation using a structured clinical interview (SCID-1), an anthropometric evaluation and a clinical evaluation that included blood pressure measurement and assessment of fasting blood glucose, lipid profile and physical activity levels.

RESULTS

Individuals with histories of major depression were more likely to be female (P < 0.0001). Individuals with lifetime diagnoses of major depression were more likely to be current smokers (odds ratio, OR 1.61; 95% confidence interval, CI 1.01-2.59) and to have diabetes (OR 1.79; 95% CI 1.01-3.21); and less likely to be obese (OR 0.58; 95% CI 0.35-0.94).

CONCLUSION

Individuals with major depression had higher odds of presenting tobacco smoking and diabetes, and lower odds of being obese. Healthcare professionals need to be aware of this, so as to increase the rates of diagnosis and treatment in this population.

Longitudinal Trends in Childhood Insulin Levels and Body Mass Index and Associations With Risks of Psychosis and Depression in Young Adults

IMPORTANCE

Cardiometabolic disorders often occur concomitantly with psychosis and depression, contribute to high mortality rates, and are detectable from the onset of the psychiatric disorders. However, it is unclear whether longitudinal trends in cardiometabolic traits from childhood are associated with risks for adult psychosis and depression.

OBJECTIVE

To examine whether specific developmental trajectories of fasting insulin (FI) levels and body mass index (BMI) from early childhood were longitudinally associated with psychosis and depression in young adults.

DESIGN, SETTING, AND PARTICIPANTS

A cohort study from the Avon Longitudinal Study of Parents and Children, a prospective study including a population-representative British cohort of 14 975 individuals, was conducted using data from participants aged 1 to 24 years. Body mass index and FI level data were used for growth mixture modeling to delineate developmental trajectories, and associations with psychosis and depression were assessed. The study was conducted between July 15, 2019, and March 24, 2020.

EXPOSURES

Fasting insulin levels were measured at 9, 15, 18, and 24 years, and BMI was measured at 1, 2, 3, 4, 7, 9, 10, 11, 12, 15, 18, and 24 years. Data on sex, race/ethnicity, paternal social class, childhood emotional and behavioral problems, and cumulative scores of sleep problems, average calorie intake, physical activity, smoking, and alcohol and substance use in childhood and adolescence were examined as potential confounders.

MAIN OUTCOMES AND MEASURES

Psychosis risk (definite psychotic experiences, psychotic disorder, at-risk mental state status, and negative symptom score) depression risk (measured using the computerized Clinical Interview Schedule-Revised) were assessed at 24 years.

RESULTS

From data available on 5790 participants (3132 [54.1%] female) for FI levels and data available on 10 463 participants (5336 [51.0%] female) for BMI, 3 distinct trajectories for FI levels and 5 distinct trajectories for BMI were noted, all of which were differentiated by mid-childhood. The persistently high FI level trajectory was associated with a psychosis at-risk mental state (adjusted odds ratio [aOR], 5.01; 95% CI, 1.76-13.19) and psychotic disorder (aOR, 3.22; 95% CI, 1.29-8.02) but not depression (aOR, 1.38; 95% CI, 0.75-2.54). A puberty-onset major increase in BMI was associated with depression (aOR, 4.46; 95% CI, 2.38-9.87) but not psychosis (aOR, 1.98; 95% CI, 0.56-7.79).

CONCLUSIONS AND RELEVANCE

The cardiometabolic comorbidity of psychosis and depression may have distinct, disorder-specific early-life origins. Disrupted insulin sensitivity could be a shared risk factor for comorbid cardiometabolic disorders and psychosis. A puberty-onset major increase in BMI could be a risk factor or risk indicator for adult depression. These markers may represent targets for prevention and treatment of cardiometabolic disorders in individuals with psychosis and depression.

Oridonin ameliorates insulin resistance partially through inhibition of inflammatory response in rats subjected to chronic unpredictable mild stress

BACKGROUND

Oridonin (Ori) has multiple biological properties, especially anti-inflammatory. However, its effects on chronic unpredictable mild stress (CUMS)-induced insulin resistance are still unclear. In this study, we explored the regulatory role of Ori in CUMS-triggered insulin resistance, and the underlying molecular mechanisms; Methods: SD rats were subjected to CUMS for 4 weeks, some of which were injected with Ori or fluoxetine (FLX) in durations of CUMS. After CUMS procedure, the behavioral and metabolic tests were performed. Elisa, immunofluorescence and western blotting were used to determine the inflammatory response and NLRP3 inflammasome activation. We investigated the interaction between NLRP3 and NEK7 using immunoprecipitation. Finally, we detected the proinflammatory cytokines in Lipopolysaccharide (LPS)-activated RAW264.7 cells treated with Ori; RESULTS: In this study, we found that chronic stress resulted in depressive-like behavior comorbid with insulin resistance. Ori was discovered to ameliorate insulin resistance as well as insulin signaling disturbance in the hippocampus. In addition, CUMS caused the infiltration of macrophages into the islets. And IL-1β, IL-18 and caspase-1 were elevated in pancreases of CUMS rats, which could also be reversed by Ori treatment via reducing the interaction between NLRP3 and NEK7. Furthermore, Ori dose-dependently inhibited the levels of IL-1β and IL-18 in LPS-activated RAW264.7 cells; CONCLUSIONS: All these results supported our hypothesis that Ori possesses potent anti-insulin resistant actions, which is partially correlated with inhibiting infiltration of macrophages into the islets and NLRP3 activation induced by CUMS. Therefore, our results highlighted the protective role of Ori against CUMS-elicited insulin resistance.

Cardiometabolic risk in young adults with depression and evidence of inflammation: A birth cohort study

BACKGROUND

Young adults with depression and evidence of inflammation may represent a high-risk group for cardiometabolic disorders, but studies of cardiometabolic risk in this population are scarce. We aimed to examine: (1) the prevalence of low-grade inflammation in young-adults with depression; (2) cross-sectional and longitudinal associations between cardiometabolic risk factors and depression with or without evidence of inflammation.

METHOD

The ALSPAC birth cohort participants were assessed for depression and serum high-sensitivity C-Reactive Protein (CRP) levels at age 18, alongside cardiometabolic measures (fasting insulin, fasting plasma glucose, low-density lipoprotein, high-density lipoprotein, triglycerides, smoking, alcohol intake) at age 18 years, and body mass index at ages 9, 13 and 18 years. Low-grade inflammation was defined as CRP>3 mg/L. Multinomial regression was used to examine associations of cardiometabolic markers with depression cases with and without evidence of inflammation. Sensitivity analyses were conducted to examine for interactions between depression, inflammation and cardiometabolic traits.

RESULTS

Out of 2932 participants, 215 met ICD-10 criteria for depressive episode at age 18 years; 23 (10.7 %) had CRP>3 mg/L and 57 (26.5 %) had CRP 1-3 mg/L. Depressive episode with raised CRP (>3 mg/L) was associated with higher triglycerides (adjusted OR = 2.09; 95 % C.I., 1.35-3.24), higher BMI (adjusted OR = 1.13; 95 % C.I., 1.05-1.22) and insulin insensitivity (adjusted OR = 1.12; 95 % C.I., 1.01-1.26), and longitudinally with higher BMI at ages 9 (adjusted OR = 1.27; 95 % C.I., 1.10-1.48) and 13 (adjusted OR = 1.23; 95 % C.I., 1.09-1.38). There was evidence for interaction between BMI and CRP for the risk of depression at age 18 (adjusted OR for the interaction term = 1.56; 95 % C.I. 0.98-2.02) and between CRP and depressive symptoms for the risk of increased BMI at age 18 (adjusted β for the interaction term = 0.05; 95 % C.I. 0.00-0.12).

CONCLUSIONS

A notable proportion of young adults with depression have evidence of inflammation. These individuals are at increased risk of cardiometabolic disorders. Management of cardiometabolic risk in depressed individuals with evidence of inflammation should form part of routine clinical practice.

Insulin resistance and obesity, and their association with depression in relatively young people: findings from a large UK birth cohort

BACKGROUND

Depression frequently co-occurs with disorders of glucose and insulin homeostasis (DGIH) and obesity. Low-grade systemic inflammation and lifestyle factors in childhood may predispose to DGIH, obesity and depression. We aim to investigate the cross-sectional and longitudinal associations among DGIH, obesity and depression, and to examine the effect of demographics, lifestyle factors and antecedent low-grade inflammation on such associations in young people.

METHODS

Using the Avon Longitudinal Study of Parents and Children birth cohort, we used regression analyses to examine: (1) cross-sectional and (2) longitudinal associations between measures of DGIH [insulin resistance (IR); impaired glucose tolerance] and body mass index (BMI) at ages 9 and 18 years, and depression (depressive symptoms and depressive episode) at age 18 years and (3) whether sociodemographics, lifestyle factors or inflammation [interleukin-6 (IL-6) at age 9 years] confounded any such associations.

RESULTS

We included 3208 participants. At age 18 years, IR and BMI were positively associated with depression. These associations may be explained by sociodemographic and lifestyle factors. There were no longitudinal associations between DGIH/BMI and depression, and adjustment for IL-6 and C-reactive protein did not attenuate associations between IR/BMI and depression; however, the longitudinal analyses may have been underpowered.

CONCLUSIONS

Young people with depression show evidence of DGIH and raised BMI, which may be related to sociodemographic and lifestyle effects such as deprivation, smoking, ethnicity and gender. In future, studies with larger samples are required to confirm this. Preventative strategies for the poorer physical health outcomes associated with depression should focus on malleable lifestyle factors.

Variants in the Upstream Region of the Insulin Receptor Substrate-1 Gene Is Associated with Major Depressive Disorder in the Han Chinese Population

INTRODUCTION

Major depressive disorder (MDD) is one of the most prevalent and disabling mental disorders, although its underlying genetic mechanism remains unknown. Insulin receptor substrate-1 (IRS-1) is one of the critical downstream molecules in the insulin resistance signaling pathway, linking depression and diabetes. Therefore, we hypothesized that IRS-1 would be a susceptible gene for MDD, and we aimed to examine the genetic association between IRS-1 and MDD.

METHODS

This case-control study included 583 patients with MDD and 564 controls, and the genotypic and allelic distributions of the IRS-1 gene's four single nucleotide polymorphisms (SNPs) were detected by TaqMan SNP genotyping technology. Of the 583 patients, 191 underwent a further detailed interview about symptom severity and family history of mental illness. The chi-square or t test was used to analyze the data, and analyses were performed using SPSS19.0 software.

RESULTS

A haplotype in the 5'-upstream region of IRS-1 consisting of rs13411764 and rs3820926 was a risk factor of MDD. Patients with a family history of mental illness were more likely to have a GG genotype in rs13411764 and a G-T haplotype containing rs13411714-rs3820926.

DISCUSSION

The findings imply that the haplotype consisting of rs13411764 and rs3820926 in the upstream of IRS-1 is a risk factor for MDD. This haplotype could affect IRS-1 expression levels, and it is mostly inherited from parents. Thus, the presence of variants in the upstream region of IRS-1 is a risk factor of MDD, and this study could serve as a convincing reference for further studies.

The Finnish psychiatric birth cohort consortium (PSYCOHORTS) - content, plans and perspectives

Background: Psychiatric disorders tend to be developmental, and longitudinal settings are required to examine predictors of psychiatric phenomena. Replicating and combining data and results from different birth cohorts, which are a source of reliable data, can make research even more valuable. The Finnish Psychiatric Birth Cohort Consortium (PSYCOHORTS) project combines birth cohorts in Finland. Aim: The aim of this paper is to introduce content, plans and perspectives of the PSYCOHORTS project that brings together researchers from Finland. In addition, we illustrate an example of data harmonization using available data on causes of death. Content: PSYCOHORTS includes eight Finnish birth cohorts. The project has several plans: to harmonize different data from birth cohorts, to incorporate biobanks into psychiatric birth cohort research, to apply multigenerational perspectives, to integrate longitudinal patterns of marginalization and inequality in mental health, and to utilize data in health economics research. Data on causes of death, originally obtained from Finnish Cause of Death register, were harmonized across the six birth cohorts using SAS macro facility. Results: Harmonization of the cause of death data resulted in a total of 21,993 observations from 1965 to 2015. For example, the percentage of deaths due to suicide and the sequelae of intentional self-harm was 14% and alcohol-related diseases, including accidental poisoning by alcohol, was 13%. Conclusions: PSYCOHORTS lays the foundation for complex examinations of psychiatric disorders that is based on compatible datasets, use of biobanks and multigenerational approach to risk factors, and extensive data on marginalization and inequality.

Are plasma 25-hydroxyvitamin D and retinol levels and one-carbon metabolism related to metabolic syndrome in patients with a severe mental disorder?

There is a scarcity of studies assessing the influence of biomarkers in metabolic syndrome in psychiatric patients. Our aim was to correlate serum or plasma levels of 25-hydroxyvitamin D (25-OH-VD), retinol, vitamin B12 (VB12), folate and homocysteine (Hcy), with the metabolic status, in a sample of 289 outpatients with Schizophrenia or Bipolar Disorder. Logistic regression and multiple linear regressions were performed to assess the ability of biomarkers to predict the presence of MetS, the number of risk factors for MetS, and insulin resistance indexes (HOMA and QUICKI). Regarding the association between biomarkers and the QUICKI index, the model explained 6.8% of the variance, with folate and 25-OH-VD levels contributing significantly to the model. The model predicting the number of MetS risk factors was significant and explained 21.7% of the variance, being 25-OH-VD and retinol the statistically significant factors. As for the impact of biomarkers on MetS, the model was statistically significant, being 25-OH-VD and retinol levels the significant factors.  We report for the first time an association between MetS and both low 25-OH-VD and high retinol concentrations. Inflammation-related biomarkers may help identify patients with a high risk of MetS who might benefit from healthy lifestyle counselling and early intervention.

Melatonin receptor 1B gene rs10830963 polymorphism, depressive symptoms and glycaemic traits

BACKGROUND

The association between depression and type 2 diabetes is bidirectional. Underlying biological determinants remain elusive. We examined whether a common melatonin receptor 1B gene diabetes risk variant rs10830963 influenced the associations between depressive symptoms and glycaemic traits.

MATERIALS

The Prevalence, Prediction and Prevention of Diabetes-Botnia Study participants (n = 4,455) with no diabetes who underwent an oral glucose tolerance test were genotyped for rs10830963 and completed the Mental Health Inventory on depressive symptoms.

RESULTS

The rs10830963 did not influence significantly the associations between depressive symptoms and glycaemic traits. Yet, the addition of each copy of the minor G allele of the rs1080963 and higher depressive symptoms were both, independent of each other, associated significantly with higher glucose response (glucose area under the curve), higher insulin resistance (Insulin Sensitivity Index) and lower insulin secretion (Disposition Index). Depressive symptoms, but not rs1080963, were also significantly associated with higher fasting insulin, insulin area under the curve and insulin resistance (Homeostasis Model Assessment, Homeostasis Model Assessment-2); rs1080963, but not depressive symptoms, was significantly associated with higher fasting glucose and lower Corrected Insulin Response.

CONCLUSIONS

Our study shows that the diabetes risk variant rs10830963 does not contribute to the known comorbidity between depression and type 2 diabetes. Key messages The association between depression and type 2 diabetes is bidirectional. We tested whether a common variant rs10830963 in the gene encoding Melatonin Receptor 1B influences the known association between depressive symptoms and glycaemic traits in a population-based sample from Western Finland. The MTNR1B genetic diabetes risk variant rs10830963 does not contribute to the known comorbidity between depression and type 2 diabetes. Depressive symptoms and rs10830963 are associated with a worse glycaemic profile independently of each other.

Bivariate Genome-Wide Association Study of Depressive Symptoms With Type 2 Diabetes and Quantitative Glycemic Traits

OBJECTIVE

Shared genetic background may explain phenotypic associations between depression and Type 2 diabetes (T2D). We aimed to study, on a genome-wide level, if genetic correlation and pleiotropic loci exist between depressive symptoms and T2D or glycemic traits.

METHODS

We estimated single-nucleotide polymorphism (SNP)-based heritability and analyzed genetic correlation between depressive symptoms and T2D and glycemic traits with the linkage disequilibrium score regression by combining summary statistics of previously conducted meta-analyses for depressive symptoms by CHARGE consortium (N = 51,258), T2D by DIAGRAM consortium (N = 34,840 patients and 114,981 controls), fasting glucose, fasting insulin, and homeostatic model assessment of β-cell function and insulin resistance by MAGIC consortium (N = 58,074). Finally, we investigated pleiotropic loci using a bivariate genome-wide association study approach with summary statistics from genome-wide association study meta-analyses and reported loci with genome-wide significant bivariate association p value (p < 5 × 10). Biological annotation and function of significant pleiotropic SNPs were assessed in several databases.

RESULTS

The SNP-based heritability ranged from 0.04 to 0.10 in each individual trait. In the linkage disequilibrium score regression analyses, depressive symptoms showed no significant genetic correlation with T2D or glycemic traits (p > 0.37). However, we identified pleiotropic genetic variations for depressive symptoms and T2D (in the IGF2BP2, CDKAL1, CDKN2B-AS, and PLEKHA1 genes), and fasting glucose (in the MADD, CDKN2B-AS, PEX16, and MTNR1B genes).

CONCLUSIONS

We found no significant overall genetic correlations between depressive symptoms, T2D, or glycemic traits suggesting major differences in underlying biology of these traits. However, several potential pleiotropic loci were identified between depressive symptoms, T2D, and fasting glucose, suggesting that previously established phenotypic associations may be partly explained by genetic variation in these specific loci.

Curcumin reverses the depressive-like behavior and insulin resistance induced by chronic mild stress

Increasing evidence has demonstrated that patients with depression have a higher risk of developing type 2 diabetes. Insulin resistance has been identified as the key mechanism linking depression and diabetes. The present study established a rat model of depression complicated by insulin resistance using a 12-week exposure to chronic mild stress (CMS) and investigated the therapeutic effects of curcumin. Sucrose intake tests were used to evaluate depressive-like behaviors, and oral glucose tolerance tests (OGTT) and intraperitoneal insulin tolerance tests (IPITT) were performed to evaluate insulin sensitivity. Serum parameters were detected using commercial kits. Real-time quantitative PCR was used to examine mRNA expression. CMS rats exhibited reduced sucrose consumption, increased serum glucose, insulin, triglyceride (TG), low density lipoprotein-cholesterol (LDL-C), non-esterified fatty acid (NEFA), glucagon, leptin, and corticosterone levels, as well as impaired insulin sensitivity. Curcumin upregulated the phosphorylation of insulin receptor substrate (IRS)-1 and protein kinase B (Akt) in the liver, enhanced insulin sensitivity, and reversed the metabolic abnormalities and depressive-like behaviors mentioned above. Moreover, curcumin increased the hepatic glycogen content by inhibiting glycogen synthase kinase (GSK)-3β and prevented gluconeogenesis by inhibiting phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (G6Pase). These results suggest that curcumin not only exerted antidepressant-like effects, but also reversed the insulin resistance and metabolic abnormalities induced by CMS. These data may provide evidence to support the potential use of curcumin against depression and/or metabolic disorders.

Major Depressive Disorder and Bipolar Disorder Predispose Youth to Accelerated Atherosclerosis and Early Cardiovascular Disease: A Scientific Statement From the American Heart Association

In the 2011 "Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents," several medical conditions among youth were identified that predispose to accelerated atherosclerosis and early cardiovascular disease (CVD), and risk stratification and management strategies for youth with these conditions were elaborated. Major depressive disorder (MDD) and bipolar disorder (BD) among youth satisfy the criteria set for, and therefore merit inclusion among, Expert Panel tier II moderate-risk conditions. The combined prevalence of MDD and BD among adolescents in the United States is ≈10%, at least 10 times greater than the prevalence of the existing moderate-risk conditions combined. The high prevalence of MDD and BD underscores the importance of positioning these diseases alongside other pediatric diseases previously identified as moderate risk for CVD. The overall objective of this statement is to increase awareness and recognition of MDD and BD among youth as moderate-risk conditions for early CVD. To achieve this objective, the primary specific aims of this statement are to (1) summarize evidence that MDD and BD are tier II moderate-risk conditions associated with accelerated atherosclerosis and early CVD and (2) position MDD and BD as tier II moderate-risk conditions that require the application of risk stratification and management strategies in accordance with Expert Panel recommendations. In this scientific statement, there is an integration of the various factors that putatively underlie the association of MDD and BD with CVD, including pathophysiological mechanisms, traditional CVD risk factors, behavioral and environmental factors, and psychiatric medications.

PPAR-γ agonism as a modulator of mood: proof-of-concept for pioglitazone in bipolar depression

BACKGROUND

Insulin resistance and other cardio-metabolic risk factors predict increased risk of depression and decreased response to antidepressant and mood stabilizer treatments. This proof-of-concept study tested whether administration of an insulin-sensitizing peroxisome proliferator-activated receptor (PPAR)-γ agonist could reduce bipolar depression symptom severity. A secondary objective was to determine whether levels of highly sensitive C-reactive protein and interleukin (IL)-6 predicted treatment outcome.

METHODS

Patients (n = 34) with bipolar disorder (I, II, or not otherwise specified) and metabolic syndrome/insulin resistance who were currently depressed (Quick Inventory of Depressive Symptoms [QIDS] total score ≥11) despite an adequate trial of a mood stabilizer received open-label, adjunctive treatment with the PPAR-γ agonist pioglitazone (15-30 mg/day) for 8 weeks. The majority of participants (76 %, n = 26) were experiencing treatment-resistant bipolar depression, having already failed two mood stabilizers or the combination of a mood stabilizer and a conventional antidepressant.

RESULTS

Supporting an association between insulin sensitization and depression severity, pioglitazone treatment was associated with a decrease in the total Inventory of Depressive Symptomatology (IDS-C30) score from 38.7 ± 8.2 at baseline to 21.2 ± 9.2 at week 8 (p < 0.001). Self-reported depressive symptom severity and clinician-rated anxiety symptom severity significantly improved over 8 weeks as measured by the QIDS (p < 0.001) and Structured Interview Guide for the Hamilton Anxiety Scale (p < 0.001), respectively. Functional improvement also occurred as measured by the change in total score on the Sheehan Disability Scale (-17.9 ± 3.6; p < 0.001). Insulin sensitivity increased from baseline to week 8 as measured by the Insulin Sensitivity Index derived from an oral glucose tolerance test (0.98 ± 0.3; p < 0.001). Higher baseline levels of IL-6 were associated with greater decrease in depression severity (parameter estimate β = -3.89, standard error [SE] = 1.47, p = 0.015). A positive correlation was observed between improvement in IDS-C30 score and change in IL-6 (r = 0.44, p < 0.01).

CONCLUSIONS

Open-label administration of the PPAR-γ agonist pioglitazone was associated with improvement in depressive symptoms and reduced cardio-metabolic risk. Reduction in inflammation may represent a novel mechanism by which pioglitazone modulates mood. (ClinicalTrials.gov Identifier: NCT00835120).

Relationship between major depression and insulin resistance: does it vary by gender or race/ethnicity among young adults aged 20-39 years?

BACKGROUND

To examine the relationship between major depression and insulin resistance by gender and race/ethnicity among young adults without diabetes mellitus.

METHODS

Secondary analyses of cross-sectional data from the National Health and Nutrition Examination Survey 1999-2008 were performed (n = 2265). Major depression was measured by the Composite International Diagnostic Interview and the Patient Health Questionnaire 9. Insulin resistance was measured by the homeostasis model assessment of insulin resistance. Multivariate logistic regression analyses adjusted for risk factors of insulin resistance were conducted.

RESULTS

There was a significant negative association between major depression and insulin resistance among men. For women, no significant association was found. There was no significant interaction between race/ethnicity and major depression on insulin resistance (Wald χ(2) = 4.2927, P = 0.2315). Body mass index (BMI) and waist circumference (WC) were significantly associated with insulin resistance among both men (odds ratio [OR] 1.255, 95% confidence interval [CI] 1.195-1.318 for BMI; OR 1.095, 95% CI 1.076-1.115 for WC) and women (OR 1.220, 95% CI 1.182-1.260 for BMI; OR 1.084, 95% CI 1.064-1.105 for WC).

CONCLUSIONS

There are gender differences in the relationship between major depression and insulin resistance among adults aged 20-39 years. No evidence was found to support the role of race/ethnicity in this relationship. Health care professionals should be aware of risk factors for insulin resistance and develop interventions to help prevent the progression of insulin resistance to type 2 diabetes mellitus.

Association of depression with accelerated cognitive decline among patients with type 2 diabetes in the ACCORD-MIND trial

IMPORTANCE

Depression has been identified as a risk factor for dementia among patients with type 2 diabetes mellitus but the cognitive domains and patient groups most affected have not been identified.

OBJECTIVE

To determine whether comorbid depression in patients with type 2 diabetes accelerates cognitive decline.

DESIGN

A 40-month cohort study of participants in the Action to Control Cardiovascular Risk in Diabetes-Memory in Diabetes (ACCORD-MIND) trial.

SETTING

Fifty-two clinics organized into 6 clinical networks across the United States and Canada.

PARTICIPANTS

Two thousand nine hundred seventy-seven participants with type 2 diabetes at high risk for cardiovascular events.

INTERVENTION

The Digit Symbol Substitution Test, Rey Auditory Verbal Learning Test, and the modified Stroop test were used to assess cognition. The 9-item Patient Health Questionnaire was used to assess depression.

MAIN OUTCOMES AND MEASURES

Mixed-effects statistical models were used to analyze cognitive test outcomes incorporating depression as a time-dependent covariate.

RESULTS

Participants with scores indicative of depression (9-item Patient Health Questionnaire, ≥10) showed greater cognitive decline during 40-month follow-up on all tests, with the following differences in estimated least squares means: Digit Symbol Substitution Test, 0.72 (95% CI, 0.25 to 1.19; P = .003), Rey Auditory Verbal Learning Test, 0.18 (95% CI, 0.07 to 0.29; P = .001), and Stroop interference, -1.06 (95% CI, -1.93 to -0.18; P = .02). This effect of depression on risk of cognitive decline did not differ according to previous cardiovascular disease; baseline cognition or age; or intensive vs standard glucose-lowering treatment, blood pressure treatment, lipid treatment, or insulin treatment. Addition of demographic and clinical covariates to models did not significantly change the cognitive decline associated with depression.

CONCLUSIONS AND RELEVANCE

Depression in patients with type 2 diabetes was associated with greater cognitive decline in all domains, across all treatment arms, and in all participant subgroups assessed. Future randomized trials will be necessary to determine if depression treatment can lower the risk of cognitive decline in patients with diabetes.

Cardiovascular and metabolic risk profile in young people at familial risk of depression

BACKGROUND

Depression is associated with increased risk of several general medical conditions, including diabetes and cardiovascular disease. The nature of the association is complex and may involve bidirectional causation or a common pathophysiology.

AIMS

To determine whether young people without depression but at increased familial risk have altered metabolic and blood pressure markers relative to matched controls.

METHOD

We studied young people (n = 85), who had a parent with depression but no personal history of depressive illness (FH+) and healthy controls (n = 69). Cardiovascular risk profile was assessed by a fasting blood sample to measure insulin, glucose, lipids and high-sensitivity C-reactive protein (CRP) and blood pressure was measured centrally and peripherally. Arterial stiffness and waking cortisol concentration were also measured.

RESULTS

Compared with controls, the FH+ group demonstrated increased peripheral and central systolic blood pressure, increased arterial stiffness and diminished insulin sensitivity but they did not differ from controls in measures of lipids, CRP or waking cortisol.

CONCLUSIONS

Our data suggest that young people at increased familial risk of depression show evidence of altered cardiovascular risk profile in young adulthood even in the absence of depressive symptoms. It is possible therefore that vulnerability to conditions such as hypertension and diabetes may precede the onset of major depression and may share common risk factors.

Hypothalamic orexin prevents hepatic insulin resistance induced by social defeat stress in mice

Depression is associated with insulin resistance and type 2 diabetes, although the molecular mechanism behind the pathological link remains unclear. Orexin, a hypothalamic neuropeptide regulating energy and glucose homeostasis, has been implicated in the endogenous antidepressant mechanism. To clarify whether orexin is involved in the coordination between mental and metabolic functions, we investigated the influence of orexin deficiency on social interaction behavior and glucose metabolism in mice subjected to chronic social defeat stress. Chronic stress-induced glucose intolerance and systemic insulin resistance as well as social avoidance were ameliorated by calorie restriction in an orexin-dependent manner. Moreover, orexin-deficient mice maintained under ad libitum-fed conditions after defeat stress exhibited hyperinsulinemia and elevated HOMA-IR (homeostasis model assessment for insulin resistance), despite normal fasting blood glucose levels. In a pyruvate tolerance test to evaluate hepatic insulin sensitivity, chronic stress-induced abnormal glucose elevation was observed in orexin-deficient but not wild-type mice, although both types of mice were susceptible to chronic stress. In addition, insulin-induced phosphorylation of Akt in the liver was impaired in orexin-deficient but not wild-type mice after chronic stress. These results demonstrate that the central physiological actions of orexin under ad libitum-fed conditions are required for the adaptive response to chronic defeat stress, which can prevent the development of hepatic insulin resistance but not social avoidance behavior. Moreover, calorie restriction, a paradigm to strongly activate orexin neurons, appears to prevent the persistence of depression-like behavior per se, leading to the amelioration of impaired glucose metabolism after chronic stress; therefore, we suggest that hypothalamic orexin system is the key for inhibiting the exacerbating link between depression and type 2 diabetes.

Association between vitamin b12 levels and melancholic depressive symptoms: a Finnish population-based study

BACKGROUND

An association between vitamin B12 levels and depressive symptoms (DS) has been reported in several epidemiological studies. The purpose of this study was to evaluate vitamin B12 levels in population-based samples with melancholic or non-melancholic DS as the relationship between vitamin B12 levels and different subtypes of DS has not been evaluated in previous studies.

METHODS

Subjects without previously known type 2 diabetes, aged 45-74 years were randomly selected from the National Population Register as a part of the Finnish diabetes prevention programme (FIN-D2D). The study population (N = 2806, participation rate 62%) consisted of 1328 men and 1478 women. The health examinations were carried out between October and December 2007 according to the WHO MONICA protocol. The assessment of DS was based on the Beck Depression Inventory (BDI, cut-off ≥10 points). A DSM-IV- criteria based summary score of melancholic items in the BDI was used in dividing the participants with DS (N = 429) into melancholic (N = 138) and non-melancholic DS (N = 291) subgroups. In the statistical analysis we used chi-squared test, t-test, permutation test, analysis of covariance, multivariate logistic regression analysis and multinomial regression model.

RESULTS

The mean vitamin B12 level was 331±176 pmol/L in those without DS while the subjects with non-melancholic DS had a mean vitamin B12 level of 324 ± 135 pmol/L, and those with melancholic DS had the lowest mean vitamin B12 level of 292±112 pmol/L (p < 0.001 after adjusted for age, sex, use of antidepressive medication and chronic diseases sum index). The adjusted difference of vitamin B12 levels between the non-melancholic and the melancholic group was 33 pmol/L (95%CI 8 to 57, p = 0.008). Melancholic DS and vitamin B12 levels showed an independent linearly inverse association. The relative risk ratio (RRR) for melancholic DS was 2.75 (95%CI 1.66 to 4.56) in the lowest vitamin B12 level tertile versus the highest (p for linearity <0.001) when those without DS formed the reference group. The RRR in the non-melancholic subgroup was nonsignificant.

CONCLUSIONS

The vitamin B12 level was associated with melancholic DS but not with non-melancholic DS.

Glycemia, insulin resistance, insulin secretion, and risk of depressive symptoms in middle age

OBJECTIVE

The extent to which abnormal glucose metabolism increases the risk of depression remains unclear. In this study, we investigated prospective associations of levels of fasting glucose and fasting insulin and indices of insulin resistance and secretion with subsequent new-onset depressive symptoms (DepS).

RESEARCH DESIGN AND METHODS

In this prospective cohort study of 3,145 adults from the Whitehall II Study (23.5% women, aged 60.6 ± 5.9 years), baseline examination included fasting glucose and insulin level, the homeostasis model assessment of insulin resistance (HOMA2-%IR), and the homeostasis model assessment of β-cell insulin secretion (HOMA2-%B). DepS (Center for Epidemiologic Studies Depression Scale ≥16 or use of antidepressive drugs) were assessed at baseline and at 5-year follow-up.

RESULTS

Over the 5-year follow-up, DepS developed in 142 men and 84 women. Women in the lowest quintile of insulin secretion (HOMA2-%B ≤55.3%) had 2.18 (95% CI 1.25-3.78) times higher odds of developing DepS than those with higher insulin secretion. This association was not accounted for by inflammatory markers, cortisol secretion, or menopausal status and hormone replacement therapy. Fasting insulin measures were not associated with DepS in men, and fasting glucose measures were not associated with new-onset DepS in either sex.

CONCLUSIONS

Low insulin secretion appears to be a risk factor for DepS in middle-aged women, although further work is required to confirm this finding.

Psychosocial factors associated with depressive mood in Israeli obese adolescents

This study aimed to compare levels of depressive symptoms between normal-weight and obese Israeli adolescents and to identify sociodemographic factors that may explain differences in depression between these groups. Thirty normal-weight and 49 obese patients aged 12–18 years participated in this study. The obese group had a significantly higher depression score. On linear regression analysis, obesity, lower parental income, and lower self-esteem were significantly associated with a higher depression score. This model explained 32.4 percent of the variance. The results indicate that psychosocial assessment and identification of depressive signs should be considered integral components in the management of adolescent obesity.

A systematic review and meta-analysis of the association between depression and insulin resistance

OBJECTIVE

Depression is associated with the onset of type 2 diabetes. A systematic review and meta-analysis of observational studies, controlled trials, and unpublished data was conducted to examine the association between depression and insulin resistance (IR).

RESEARCH DESIGN AND METHODS

Medline, EMBASE, and PsycINFO were searched for studies published up to September 2011. Two independent reviewers assessed the eligibility of each report based on predefined inclusion criteria (study design and measure of depression and IR, excluding prevalent cases of diabetes). Individual effect sizes were standardized, and a meta-analysis was performed to calculate a pooled effect size using random effects. Subgroup analyses and meta-regression were conducted to explore any potential source of heterogeneity between studies.

RESULTS

Of 967 abstracts reviewed, 21 studies met the inclusion criteria of which 18 studies had appropriate data for the meta-analysis (n = 25,847). The pooled effect size (95% CI) was 0.19 (0.11-0.27) with marked heterogeneity (I(2) = 82.2%) using the random-effects model. Heterogeneity between studies was not explained by age or sex, but could be partly explained by the methods of depression and IR assessments.

CONCLUSIONS

A small but significant cross-sectional association was observed between depression and IR, despite heterogeneity between studies. The pathophysiology mechanisms and direction of this association need further study using a purposively designed prospective or intervention study in samples at high risk for diabetes.

Brain insulin dysregulation: implication for neurological and neuropsychiatric disorders

Arduous efforts have been made in the last three decades to elucidate the role of insulin in the brain. A growing number of evidences show that insulin is involved in several physiological function of the brain such as food intake and weight control, reproduction, learning and memory, neuromodulation and neuroprotection. In addition, it is now clear that insulin and insulin disturbances particularly diabetes mellitus may contribute or in some cases play the main role in development and progression of neurodegenerative and neuropsychiatric disorders. Focusing on the molecular mechanisms, this review summarizes the recent findings on the involvement of insulin dysfunction in neurological disorders like Alzheimer's disease, Parkinson's disease and Huntington's disease and also mental disorders like depression and psychosis sharing features of neuroinflammation and neurodegeneration.

Association between folate intake and melancholic depressive symptoms. A Finnish population-based study

BACKGROUND

An association between low blood folate levels and depressive symptoms (DS) has been reported in several epidemiological studies, but no studies have examined folate intake in melancholic or non-melancholic DS in population-based samples.

METHODS

The aim of the study was to evaluate folate intake in DS with or without melancholic characteristics as a part of the Finnish diabetes prevention program (FIN-D2D). Altogether, 4500 randomly selected subjects aged 45-74 years were selected from the National Population Register. The study population (N=2806, participation rate 62%) consisted of 1328 men and 1478 women. The health examinations were carried out in 2007 according to the WHO MONICA project. The assessment of DS was based on the Beck Depression Inventory (BDI, cut-off≥10 points). A summary score of melancholic items in the BDI was used in dividing the participants with DS (N=429) into melancholic (N=138) and non-melancholic DS (N=291) subgroups. Folate intake was assessed using a validated food frequency questionnaire (FFQ).

RESULTS

DS associated linearly with gender specific tertiles of folate intake (p for linearity=0.003). The OR for melancholic DS was 0.55 (95%CI 0.34 to 0.90) for the high tertile of folate intake versus the low (p for linearity=0.018), while the ORs for non-melancholic DS were nonsignificant.

LIMITATIONS

Assessment of DS was based on a self-rating scale, and the population was in advanced middle-aged.

CONCLUSIONS

A low folate intake was associated with DS through its effect on melancholic DS.

A review of the association between depression and insulin resistance: pitfalls of secondary analyses or a promising new approach to prevention of type 2 diabetes?

We review the validity of the evidence for an association between depression and the risk of insulin resistance (IR). We describe the potentially plausible biological and behavioral mechanisms that explain how depression increases the risk of IR and consequent overt diabetes. We have identified gaps in the literature to guide future research. Evidence for bidirectional associations between depression and IR is inconsistent. Results showing positive associations between depression and IR are derived from cross-sectional studies, whereas negative findings are typically reported in cohort studies. On the other hand, tentative trial evidence suggests that the effective treatment of depression can improve IR, and that lifestyle programs improve IR and reduce depressive symptoms. These emerging themes could lead to potential new multidisciplinary approaches to preventing diabetes.

Prevalence of metabolic syndrome in subjects with melancholic and non-melancholic depressive symptoms. A Finnish population-based study

BACKGROUND

We aimed to evaluate the prevalence of the metabolic syndrome (MetS) and its components in subjects with predominantly melancholic or non-melancholic depressive symptoms (DS) in a population-based study evaluating the efficacy of the Finnish diabetes prevention program (FIN-D2D).

METHODS

Altogether, 4500 randomly-selected Finnish men and women aged 45-74 years were initially enrolled from the National Population Register: 2820 (63%) attended a health examination. Diagnosis of MetS was based on the criteria of the National Cholesterol Education Program (NCEP-ATPIII), and DS on the 21-item Beck Depression Inventory (BDI-21, ≥10 points). A summary score of the melancholic items in the BDI was used to divide the subjects with DS (N=432) into melancholic and a non-melancholic sub-groups.

RESULTS

The prevalence of MetS was higher among subjects with non-melancholic DS compared to those with melancholic DS (69 % versus 55%, p 0.004). The prevalence of MetS among subjects without DS was 51%. The sex- and age-adjusted odd ratio (OR) for MetS was 2.10 (95%CI 1.62 to 2.73, p<0.001) when comparing the non-melancholic and non-depressed groups, 1.15 (95%CI 0.81 to 1.61, p=0.44) for the melancholic and non-depressed groups, and 1.84 (95%CI 1.20 to 2.80, p=0.005) for the non-melancholic and melancholic groups.

LIMITATIONS

DS were based on a self-rating scale, and due to the cross-sectional design of our study, we cannot make inferences of causality.

CONCLUSIONS

Compared to subjects without DS and those with melancholic DS, persons with non-melancholic DS may more frequently suffer from MetS.

Association of depression with increased risk of dementia in patients with type 2 diabetes: the Diabetes and Aging Study

CONTEXT

Although depression is a risk factor for dementia in the general population, its association with dementia among patients with diabetes mellitus has not been well studied.

OBJECTIVE

To determine whether comorbid depression in patients with type 2 diabetes increases the risk of development of dementia.

DESIGN

The Diabetes and Aging Study was a cohort investigation that surveyed a racially/ethnically stratified random sample of patients with type 2 diabetes.

SETTING

A large, integrated, nonprofit managed care setting in Northern California.

PARTICIPANTS

A sample of 19,239 diabetes registry members 30 to 75 years of age.

MAIN OUTCOME MEASURES

The Patient Health Questionnaire 8, International Classification of Diseases, Ninth Revision (ICD-9) diagnoses of depression, and/or antidepressant prescriptions in the 12 months prior to baseline were used to identify prevalent cases of depression. Clinically recognized dementia was identified among subjects with no prior ICD-9 Clinical Modification (ICD-9-CM) diagnoses of dementia. To exclude the possibility that depression was a prodrome of dementia, dementia diagnoses were only based on ICD-9-CM diagnoses identified in years 3 to 5 postbaseline. The risk of dementia for patients with depression and diabetes relative to patients with diabetes alone was estimated using Cox proportional hazard regression models that adjusted for sociodemographic, clinical, and health risk factors and health use.

RESULTS

During the 3- to 5-year period, 80 of 3766 patients (2.1%) with comorbid depression and diabetes (incidence rate of 5.5 per 1000 person-years) vs 158 of 15,473 patients (1.0%) with diabetes alone (incidence rate of 2.6 per 1000 person-years) had 1 or more ICD-9-CM diagnoses of dementia. Patients with comorbid depression had a 100% increased risk of dementia during the 3 to 5 years postbaseline (adjusted hazard ratio, 2.02; 95% confidence interval, 1.73-2.35).

CONCLUSION

Depression in patients with diabetes was associated with a substantively increased risk for development of dementia compared with those with diabetes alone.

Depressive symptoms, antidepressant medication use, and insulin resistance: the PPP-Botnia Study

OBJECTIVE

Although insulin resistance (IR) may underlie associations between depressive symptoms and diabetes, previous findings have been contradictory. We examined whether depressive symptoms associate with IR and insulin secretion, and, additionally, whether antidepressant medication use may modulate such associations.

RESEARCH DESIGN AND METHODS

A total of 4,419 individuals underwent an oral glucose tolerance test (OGTT). Participants with previously or newly diagnosed diabetes are excluded from this sample. The homeostasis model assessment of IR (HOMA-IR) and corrected insulin response (CIR) were calculated. Depressive symptoms and antidepressant medication use were self-reported.

RESULTS

After controlling for confounding factors, depressive symptoms were associated with higher fasting and 30-min insulin during the OGTT and higher HOMA-IR but not CIR. Antidepressant medication use failed to modify these associations.

CONCLUSIONS

Depressive symptoms are associated with IR but not with changes in insulin response when corrected for IR in individuals without previously or newly diagnosed diabetes.

Functional biomarkers of depression: diagnosis, treatment, and pathophysiology

Major depressive disorder (MDD) is a heterogeneous illness for which there are currently no effective methods to objectively assess severity, endophenotypes, or response to treatment. Increasing evidence suggests that circulating levels of peripheral/serum growth factors and cytokines are altered in patients with MDD, and that antidepressant treatments reverse or normalize these effects. Furthermore, there is a large body of literature demonstrating that MDD is associated with changes in endocrine and metabolic factors. Here we provide a brief overview of the evidence that peripheral growth factors, pro-inflammatory cytokines, endocrine factors, and metabolic markers contribute to the pathophysiology of MDD and antidepressant response. Recent preclinical studies demonstrating that peripheral growth factors and cytokines influence brain function and behavior are also discussed along with their implications for diagnosing and treating patients with MDD. Together, these studies highlight the need to develop a biomarker panel for depression that aims to profile diverse peripheral factors that together provide a biological signature of MDD subtypes as well as treatment response.

Epidemiology and treatment of depression in patients with chronic medical illness

There is a bidirectional relationship between depression and chronic medical disorders. The adverse health risk behaviors and psychobiological changes associated with depression increase the risk for chronic medical disorders, and biological changes and complications associated with chronic medical disorders may precipitate depressive episodes. Comorbid depression is associated with increased medical symptom burden, functional impairment, medical costs, poor adherence to self-care regimens, and increased risk of morbidity and mortality in patients with chronic medical disorders. Depression may worsen the course of medical disorders because of its effect on proinflammatory factors, hypothalamic-pituitary axis, autonomic nervous system, and metabolic factors, in addition to being associated with a higher risk of obesity, sedentary lifestyle, smoking, and poor adherence to medical regimens. Both evidence-based psychotherapies and antidepressant medication are efficacious treatments for depression. Collaborative depression care has been shown to be an effective way to deliver these treatments to large primary care populations with depression and chronic medical illness.

The effect of a 4-week treatment with reboxetine on metabolic parameters of depressed inpatients

In the present study, we examined several metabolic parameters in a group of 19 acutely depressed inpatients with major depression (DSM-IV) at baseline and investigated their development after 4 weeks of antidepressant treatment with reboxetine (8-12 mg per day). We performed oral glucose tolerance tests and additionally assessed free saliva cortisol and post-dexamethasone cortisol levels, as well as whole cholesterol, HDL- and LDL-cholesterol, triglycerides, free fatty acids, waist and hip circumference, heart rate, systolic and diastolic blood pressure. Furthermore, we evaluated the incidence of a metabolic syndrome and investigated the metabolic changes in depressed patients with and without a metabolic syndrome. We found 42.1% of patients to fulfil the criteria for a metabolic syndrome. Overall, reboxetine was well tolerated with essentially no side effects during the observation period. A 4-week treatment with reboxetine showed a beneficial effect on several metabolic parameters that was independent from treatment outcome and could therefore theoretically be attributed to the pharmacological profile of the drug. Due to the preliminary character of the present investigation, no conclusions about the clinical efficacy of reboxetine can be drawn.

Major depressive disorder and insulin resistance in nondiabetic young adults in the United States: the National Health and Nutrition Examination Survey, 1999-2002

OBJECTIVE

The association between depression and insulin resistance has been evaluated in previous studies with conflicting results. This study aimed to explore the relationship between major depressive disorder (MDD) and insulin resistance among nondiabetic young adult men and women in the United States.

METHOD

Analyses of cross-sectional data from the National Health and Nutrition Examination Survey (NHANES), 1999-2002, were conducted. The nationally representative sample consisted of 279 men and 358 women aged 20-39 years. MDD was determined by the WHO Composite International Diagnostic Interview (CIDI). Insulin resistance was measured by the homeostasis model assessment for insulin resistance.

RESULTS

Of 637 subjects, 16 men and 18 women had MDD (weighted percentage = 6.6%, SE = 1.2). Using logistic regression, no significant association was found between MDD and insulin resistance among the nondiabetic young adults in bivariate analysis (β = -0.01, OR = 0.99, 95% CI = [0.38, 2.57], p = .98). A significant interaction effect between gender and MDD was observed. For men, MDD was negatively associated with insulin resistance after adjusting for age, race/ethnicity, waist circumference, smoking status, systolic blood pressure and triglyceride level (β = -2.12, OR = 0.12, 95% CI = [0.02, 0.62], p = .01). No significant association between MDD and insulin resistance among women was found (β = 0.61, OR = 1.84, 95% CI = [0.47, 7.14], p = .38).

CONCLUSIONS

Overall findings suggest there is no significant association between MDD and insulin resistance among nondiabetic young adults aged 20-39 years. However, gender differences in this relationship were noted.

Depression and insulin resistance: cross-sectional associations in young adults

OBJECTIVE

To examine the association between depressive disorder and insulin resistance in a sample of young adults using the Composite International Diagnostic Interview to ascertain depression status.

RESEARCH DESIGN AND METHODS

Cross-sectional data were collected from 1,732 participants aged between 26 and 36 years. Insulin resistance was derived from blood chemistry measures of fasting insulin and glucose using the homeostasis model assessment method. Those identified with mild, moderate, or severe depression were classified as having depressive disorder.

RESULTS

The 12-month prevalence of depressive disorder was 5.4% among men and 11.7% among women. In unadjusted models mean insulin resistance was 17.2% (95% CI 0.7-36.0%, P = 0.04) higher in men and 11.4% (1.5-22.0%, P = 0.02) higher in women with depressive disorder. After adjustment for behavioral and dietary factors, the increased level of insulin resistance associated with depressive disorder was 13.2% (-3.1 to 32.3%, P = 0.12) in men and 6.1% (-4.1 to 17.4%, P = 0.25) in women. Waist circumference was identified as a mediator in the relationship between depression and insulin resistance, reducing the beta coefficient in the fully adjusted models in men by 38% and in women by 42%.

CONCLUSIONS

A positive association was found between depressive disorder and insulin resistance in this population-based sample of young adult men and women. The association seemed to be mediated partially by waist circumference.

Role of orexin in the regulation of glucose homeostasis

Orexin-A (hypocretin-1) and orexin-B (hypocretin-2) are hypothalamic neuropeptides that play key roles in the regulation of wakefulness, feeding, reward, autonomic functions and energy homeostasis. To control these functions indispensable for survival, orexin-expressing neurones integrate peripheral metabolic signals, interact with many types of neurones in the brain and modulate their activities via the activation of orexin-1 receptor or orexin-2 receptor. In addition, a new functional role of orexin is emerging in the regulation of insulin and leptin sensitivities responsible for whole-body glucose metabolism. Recent evidence indicates that orexin efficiently protects against the development of peripheral insulin resistance induced by ageing or high-fat feeding in mice. In particular, the orexin receptor-2 signalling appears to confer resistance to diet-induced obesity and insulin insensitivity by improving leptin sensitivity. In fact, the expression of orexin gene is known to be down-regulated by hyperglycaemia in the rodent model of diabetes, such as ob/ob and db/db mice. Moreover, the levels of orexin receptor-2 mRNA have been shown to decline in the brain of mice along with ageing. These suggest that hyperglycaemia due to insulin insensitivity during ageing or by habitual consumption of a high-fat diet leads to the reduction in orexin expression in the hypothalamus, thereby further exacerbating peripheral insulin resistance. Therefore, orexin receptor controlling hypothalamic insulin/leptin actions may be a new target for possible future treatment of hyperglycaemia in patients with type 2 diabetes.

Depression, depression treatment, and insulin sensitivity in adults at risk for type 2 diabetes

AIMS

To compare insulin sensitivity (Si) in adults at risk for type 2 diabetes (T2DM) who were categorized as non-depressed, treated for depression and untreated depression after controlling for physical activity (PA).

METHODS

Baseline data was analyzed from individuals enrolled in a diabetes prevention program (n=56). Si was calculated using the whole-body insulin sensitivity method. The Centers for Epidemiologic Studies Depression Scale (CESD) was used to assess depressive symptoms and depressed cases were identified using a cutoff of >or=16. Depression treatment was identified using a self-report form validated by medical chart review. The PA subscale of the Health Promoting Lifestyle Profile was used to determine PA levels.

RESULTS

One third of participants had elevated depressive symptoms; 19% were taking antidepressant medication. Mean Si was 3.1 (+/-1.9). In ANOVA, depressed individuals showed significantly lower Si (M=1.8+/-0.9) than non-depressed individuals (M=3.4+/-1.8). However, individuals taking antidepressant medications had Si similar to non-depressed individuals (M=3.7+/-2.3: p=.63). In ANCOVA this association remained after controlling for PA.

CONCLUSIONS

These data suggest that in adults at high risk for T2DM, depression treatment may improve insulin resistance observed in depression. Healthcare practitioners are encouraged to screen, treat, or refer their patients with depression for treatment.

Depressive symptoms predispose females to metabolic syndrome: a 7-year follow-up study

OBJECTIVE

To evaluate the risk for developing metabolic syndrome when having depressive symptoms.

METHOD

The prevalence of depressive symptoms and metabolic syndrome at baseline, and after a 7-year follow-up as measured with Beck depression inventory (BDI), and using the modified National Cholesterol Education Program--Adult Treatment Panel III criteria for metabolic syndrome (MetS) were studied in a middle-aged population-based sample (n = 1294).

RESULTS

The logistic regression analysis showed a 2.5-fold risk (95% CI: 1.2-5.2) for the females with depressive symptoms (BDI >or=10) at baseline to have MetS at the end of the follow-up. The risk was highest in the subgroup with more melancholic symptoms evaluated with a summary score of the melancholic items in BDI (OR 6.81, 95% CI: 2.09-22.20). In men, there was no risk difference.

CONCLUSION

The higher risks for MetS in females with depressive symptoms at baseline suggest that depression may be an important predisposing factor for the development of MetS.

Insulin resistance and depressive symptoms in middle-aged and elderly Chinese: findings from the Nutrition and Health of Aging Population in China Study

BACKGROUND

Depression is associated with an increased risk of incident diabetes, and insulin resistance is thought to be the underlying link between them. Nevertheless, only a few studies have explored the association between insulin resistance and depression with contradictory results, and none have been conducted in Chinese populations.

METHODS

We aimed to determine the association between insulin resistance and depressive symptoms among middle-aged and elderly Chinese using data from the Nutrition and Health of Aging Population in China Study, a population-based cross-sectional study conducted in 2005 in China. Participants included 3285 community residents aged 50-70 years. Depressive symptoms were defined as a Center for Epidemiological Studies of Depression Scale (CES-D) score of 16 or higher. Insulin resistance was calculated using the updated homeostasis model assessment (HOMA2-IR) methods.

RESULTS

Value of HOMA2-IR was significantly higher in participants with depressive symptoms (0.284 vs. 0.261, P=0.008), even after adjustment for various confounding factors in the regression model (0.311 vs. 0.291, P=0.026). Logistical regression analyses showed that participants with depressive symptoms had a higher risk of having insulin resistance (defined as in the top quartile of HOMA2-IR values, odds ratio=1.54, 95% confidence intervals=1.17-2.04).

LIMITATIONS

Due to the cross-sectional study design, causal relation remains unknown.

CONCLUSIONS

The present study found positive associations between depressive symptoms and insulin resistance among Chinese populations. Further prospective studies are needed to validate the results and find the temporal and causal relation between them.

Insulin sensitivity, proinflammatory markers and adiponectin in young males with different subtypes of depressive disorder

OBJECTIVE

This study was designed to evaluate insulin sensitivity, proinflammatory markers and adiponectin concentration in young males with different subtypes of depressive disorder.

METHODS

Nonobese young males with depressive disorder (ages between 18 years and 30 years; body mass index, BMI < or = 25 kg/m(2)) were recruited and divided into reactive depression (RD, N = 14), major depression (MD, N = 21) and bipolar depression (BD, N = 15) based on clinical course and symptom changes in Hamilton rating scale for depression (HAM-D). Fourteen age- and BMI-matched healthy males were enrolled as controls. All of the participants received a 75-g oral glucose tolerance test (OGTT). Insulin sensitivity and beta-cell function were calculated by minimal model method from the frequently sampled intravenous glucose tolerance test. Plasma C-reactive protein (CRP), adiponectin, tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) were determined.

RESULTS

Compared to the controls, insulin sensitivity (S(I)) were significantly lower in MD and BD (0.78 +/- 0.09 min(-1)/pmol and 0.75 +/- 0.09 min(-1)/pmol vs. 1.09 +/- 0.08 x 10(-5) min(-1)/pmol, P < 0.05, respectively). Acute insulin response (AIR) to intravenous glucose was elevated in BD as compared to control and RD groups (6079.9 +/- 841.8 pmol vs. 3339.8 +/- 356.4 pmol and 3494.8 +/- 337.7 pmol, P < 0.05, respectively). Plasma adiponectin level was diminished in BD group as compared to the control and RD groups (7.41 +/- 0.45 microg/ml vs. 9.07 +/- 0.54 microg/ml and 9.38 +/- 0.46 microg/ml; P < 0.05 and P < 0.01, respectively). By regression analysis, a significantly negative correlation between HAM-D score and S(I) was found in MD (r = -0.60, P = 0.005) and BD groups (r = -0.57, P = 0.04).

CONCLUSIONS

The results suggest that there is an inverse relationship between both major and bipolar depression and insulin resistance in nonobese young males.

Insulin resistance and depressive symptoms in young adult males: findings from Finnish military conscripts

OBJECTIVE

To investigate whether the association between insulin resistance (IR) and depressive symptoms is present already in young adult males. The association between IR and depression has been poorly studied, although the existence of a connection of Type II diabetes with depression is well established. We previously demonstrated at epidemiological level in two groups of men aged 31 years and 61 to 63 years that IR is linked with depressive symptoms.

METHODS

In a cross-sectional study, involving 1054 healthy Finnish male military conscripts of about 19 years of age, IR was defined through homeostasis model assessment (HOMA-IR). The severity of the depressive symptoms was evaluated through a Finnish modification of the 13-item Beck Depression Inventory (R-BDI). Moderate-to-severe depressive symptoms were said to be present, if the R-BDI score was > or = 8, and mild depressive symptoms were present if the R-BDI score was 5 to 7.

RESULTS

After adjusting for confounders, moderate-to-severe depressive symptoms increased the risk for IR, as defined by the highest decile of the HOMA-IR, up to 2.8-fold (odds ratio = 2.8; 1.2-6.5). Mild depressive symptoms were not significantly associated with IR.

CONCLUSIONS

In young adult males, co-occurring strictly defined IR seems to be positively associated with current moderate-to-severe depressive symptoms.