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

Nutritional considerations in major depressive disorder: current evidence and functional testing for clinical practice

Depression is a multifaceted condition with diverse underlying causes. Several contributing and inter-related factors such as genetic, nutritional, neurological, physiological, gut-brain-axis, metabolic and psychological stress factors play a role in the pathophysiology of depression. This review aims to highlight the role that nutritional factors play in the aetiology of depression. Secondly, we discuss the biomedical and functional pathology tests which measure these factors, and the current evidence supporting their use. Lastly, we make recommendations on how practitioners can incorporate the latest evidence-based research findings into clinical practice. This review highlights that diet and nutrition greatly affect the pathophysiology of depression. Nutrients influence gene expression, with folate and vitamin B12 playing vital roles in methylation reactions and homocysteine regulation. Nutrients are also involved in the tryptophan/kynurenine pathway and the expression of brain-derived neurotrophic factor (BDNF). Additionally, diet influences the hypothalamic-pituitary-adrenal (HPA) response and the composition and diversity of the gut microbiome, both of which have been implicated in depression. A comprehensive dietary assessment, combined with appropriate evaluation of biochemistry and blood pathology, may help uncover contributing factors to depressive symptoms. By employing such an approach, a more targeted and personalised treatment strategy can be devised, ultimately leading to improved patient outcomes.

The Role of Sarcopenia in Heart Failure with Depression

Heart failure (HF) and depression are both major medical health issues in our society. Currently, an increasing number of studies demonstrate an association between HF and depression. The prevalence of depression is higher in patients with HF, and depression also increases the incidence of HF. Currently, depression has been listed as a major risk factor for heart disease. Patients with HF and comorbid depression have significantly higher rates of hospitalization and mortality, and clinical symptoms manifest as decreased activity tolerance and decreased muscle mass. Enhancement of the muscle function improves the prognosis of patients with HF and depression. Sarcopenia is defined as age-related loss of skeletal muscle mass plus loss of muscle strength and/or reduced physical performance, and its pathogenesis involves malnutrition, physical inactivity, endocrine disorders and chronic inflammation, which are also involved in the pathogenesis of HF with comorbid depression. Therefore, it would be intriguing to explore the linkage between HF, depression and sarcopenia. This review presents an overview of HF with comorbid depression and sarcopenia, elucidates the mechanisms involved in these disorders, and finally summarizes the treatment strategies of HF with comorbid depression and sarcopenia.

Visceral Adipose Tissue Influence on Health Problem Development and Its Relationship with Serum Biochemical Parameters in Middle-Aged and Older Adults: A Literature Review

Background

The amount of visceral adipose tissue (VAT) tends to increase with age and is associated with several health problems, such as cardiometabolic diseases, increased infections, and overall mortality.

Objectives

This review provides a general assessment of how visceral adiposity correlates with the development of health problems and changes in serum biochemical parameters in middle-aged and older adults.

Methods

We searched specific terms in the Virtual Health Library (VHL) databases for VAT articles published in the English language between 2009 and 2019 related to older adults.

Results

The search found twenty-three publications in this period, of which nine were excluded. The publications had a population aged between 42 and 83 years and correlated the VAT area ratio with several comorbidities (such as pancreatitis, depression, cancer, and coronary heart disease) and serum biochemical parameters.

Conclusion

Further research on the association between visceral obesity and the emergence of health problems and the relationship between VAT and changes in serum biochemical parameters in older individuals should deepen the understanding of this connection and develop preventive actions.

The correlation between serum resistin and toll-like receptor-4 with insulin resistance in hypertensive subjects with or without type 2 diabetes mellitus

Background: The most chronic disease prevalence in the Iraqi population are type-2 diabetes mellitus (T2DM) and hypertension (HT). One of the important causes of these chronic diseases is obesity. Resistin (RETN) is a major link between obesity and insulin resistance (IR) or T2DM (which induces IR). The action of RETN on IR is mediated by Toll-like receptor-4 (TLR4). TLR4 is a putative RETN receptor that has been suggested to participate in RETN-inducing inflammation and IR. Objectives: To study the association between serum RETN/TLR4 and IR in hypertensive patients with or without T2DM subjects. Methods: This cross-sectional study was conducted on 120 men that classified into four different groups. These groups consist of the following: 30 apparently control group, 30 patients with hypertension, 30 patients with T2DM but without HT and 30 hypertensive patients with T2DM. For all the subjects, serum RETN, TLR4 and serum insulin was estimated by using the ELISA technique. Results: Our results showed that mean levels of the serum RETN and TLR4 were significantly elevated in all patient groups when compared with the control group. Also, a positive correlation between serum RETN and TLR4 was found in hypertensive patients with T2DM patients. Conclusions: Serum RETN and TLR4 were higher in all patient groups when compared with the control group. In addition, a positive correlation between RETN and IR in all study groups was noted. Then, we suggested a close association between RETN and TLR4 and their positive correlations with IR.

Current advances in metabolomic studies on non-motor psychiatric manifestations of Parkinson's disease (Review)

Life expectancy has increased worldwide and, along with it, a greater prevalence of age-dependent disorders, chronic illnesses and comorbidities can be observed. In 2019, in both Europe and the Americas, dementias ranked 3rd among the top 10 causes of death. Parkinson's disease (PD) is the second most frequent type of neurodegenerative disease. In the last decades, globally, the number of people suffering from PD has more than doubled to over 6 million. Of all the neurological disorders, PD increased with the fastest rate. This troubling trend highlights the stringent need for accurate diagnostic biomarkers, especially in the early stages of the disease and to evaluate treatment response. To gain a broad and complex understanding of the recent advances in the '-omics' research fields, electronic databases such as PubMed, Google Academic, and Science Direct were searched for publications regarding metabolomic studies on PD to identify specific biomarkers for PD, and especially PD with associated psychiatric symptomatology. Discoveries in the fields of metagenomics, transcriptomics and proteomics, may lead to an improved comprehension of the metabolic pathways involved in disease etiology and progression and contribute to the discovery of novel therapeutic targets for effective treatment options.

Depressive symptoms in Chinese adults with risk factors for diabetes: the Shanghai High-Risk Diabetic Screen (SHiDS) study

AIMS

To evaluate the relationship between newly diagnosed diabetes or prediabetes and depressive symptoms among individuals with risk factors for diabetes in China. We also investigated the associations of depressive symptoms with pancreatic β-cell function and insulin resistance.

METHODS

We used cross-sectional data from the Shanghai High-Risk Diabetic Screen (SHiDS) project. Between 2014 and 2017, a total of 1728 participants were enrolled in this study and underwent an oral glucose tolerance test to screen for diabetes and prediabetes. Insulin resistance was evaluated using the homeostatic model assessment of insulin resistance and the modified Matsuda index. Pancreatic β-cell function was calculated using the homeostatic model assessment of β-cell function, Stumvoll first- and second-phase indexes. Elevated depressive symptoms were determined using the Patient Health Questionnaire-9 (PHQ-9 score ≥ 10).

RESULTS

The prevalence of elevated depressive symptoms in the total study population was 4.8% (83 of 1728). Compared with the normal glucose tolerance group, individuals with newly diagnosed diabetes were less likely to have elevated depressive symptoms even after controlling for potential confounders [adjusted odds ratio (OR) 0.35, 95% confidence interval (CI) 0.18-0.68; P = 0.002]. However, prediabetes was not associated with depressive symptoms. The odds for elevated depressive symptoms were increased in individuals with higher levels of the Stumvoll first-phase index. No association was observed between depressive symptoms and insulin resistance.

CONCLUSION

Elevated depressive symptoms were less prevalent in Chinese individuals with newly diagnosed diabetes among a high-risk population for diabetes.

The handgrip strength and risk of depressive symptoms: a meta-analysis of prospective cohort studies

PURPOSE

Many studies have investigated the association between handgrip strength (HGS) and depressive symptoms, but the conclusion remain controversial. We performed a meta-analysis to evaluate the longitudinal association between HGS and risk of depressive symptoms.

METHODS

PubMed, PSYCINFO and EMBASE databases were searched for eligible publications up to April 2020. Pooled relative risks (RRs) with 95% confidence intervals were calculated using random-effects model. Publication bias was estimated using Egger's test and the funnel plot. Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of eligible studies.

RESULTS

The present meta-analysis included 8 cohort studies with 30,727 participants. Overall, higher HGS was related to a decreased risk of depressive symptoms: the pooled risk ratio (RR) of 0.74 [95% confidence intervals (CI) 0.65-0.85] with a moderate heterogeneity (I² = 60.5%, P = 0.013). HGS was significantly associated with a reduced risk of depressive symptoms in males (RR = 0.69; 95% CI 0.50-0.94), but not in females.

CONCLUSIONS

Lower HGS was associated with an increased risk of depressive symptoms. Further studies are needed to confirm these findings and to investigate the sex differences.

The association of hyperglycaemia and insulin resistance with incident depressive symptoms over 4 years of follow-up: The Maastricht Study

AIMS/HYPOTHESIS

Depression is twice as common in individuals with type 2 diabetes as in the general population. However, it remains unclear whether hyperglycaemia and insulin resistance are directly involved in the aetiology of depression. Therefore, we investigated the association of markers of hyperglycaemia and insulin resistance, measured as continuous variables, with incident depressive symptoms over 4 years of follow-up.

METHODS

We used data from the longitudinal population-based Maastricht Study (n = 2848; mean age 59.9 ± 8.1 years, 48.8% women, 265 incident depression cases, 10,932 person-years of follow-up). We assessed hyperglycaemia by fasting and 2 h post-load OGTT glucose levels, HbA_1c and skin autofluorescence (reflecting AGEs) at baseline. We used the Matsuda insulin sensitivity index and HOMA-IR to calculate insulin resistance at baseline. Depressive symptoms (nine-item Patient Health Questionnaire score ≥10) were assessed at baseline and annually over 4 years. We used Cox regression analyses, and adjusted for demographic, cardiovascular and lifestyle risk factors.

RESULTS

Fasting plasma glucose, 2 h post-load glucose and HbA_1c levels were associated with an increased risk for incident depressive symptoms after full adjustment (HR 1.20 [95% CI 1.08, 1.33]; HR 1.25 [1.08, 1.44]; and HR 1.22 [1.09, 1.37] per SD, respectively), while skin autofluorescence, insulin sensitivity index and HOMA-IR were not (HR 0.99 [0.86, 1.13]; HR 1.02 [0.85, 1.25]; and HR 0.93 [0.81, 1.08], per SD, respectively).

CONCLUSIONS/INTERPRETATION

The observed temporal association between hyperglycaemia and incident depressive symptoms in this study supports the presence of a mechanistic link between hyperglycaemia and the development of depressive symptoms. Graphical abstract.

Effect of Dietary Silk Peptide on Obesity, Hyperglycemia, and Skeletal Muscle Regeneration in High-Fat Diet-Fed Mice

Obesity is associated with excess body fat accumulation that can cause hyperglycemia and reduce skeletal muscle function and strength, which characterize the development of sarcopenic obesity. In this study, we aimed to determine the mechanism whereby acid-hydrolyzed silk peptide (SP) prevents high-fat diet (HFD)-induced obesity and whether it regulates glucose uptake and muscle differentiation using in vivo and in vitro approaches. Our findings demonstrate that SP inhibits body mass gain and the expression of adipogenic transcription factors in visceral adipose tissue (VAT). SP also had an anti-diabetic effect in VAT and skeletal muscle because it upregulated glucose transporter type 4 (GLUT4) and uncoupling protein 3 (UCP3) expression. Furthermore, SP reduced ubiquitin proteasome and promoted myoblast determination protein 1 (MyoD)/myogenic factor 4 (myogenin) expression, implying that it may have potential for the treatment of obesity-induced hyperglycemia and obesity-associated sarcopenia.

The relationship between visceral adiposity and depressive symptoms in the general Korean population

BACKGROUND

In Korea, depressive symptoms or depression are prevalent. Metabolic syndrome is the representative medical condition associated with depression. This study examined the association between clinically significant depressive symptoms and intra-abdominal fat, measured using abdominal computed tomography, in a large sample of the Korean population who underwent routine health examination.

METHODS

People who underwent routine health examinations at the Seoul National University Hospital Healthcare System, Gangnam Center, from October 2004 to July 2012 were included in the study. There were 11,434 cases of individuals with CT scan data and entries in the Beck Depression Inventory (BDI). Of these, 1156 men and women underwent CT scans more than once. In these cases, we analyzed the first scan.

RESULTS

We analyzed 4945 male and 2293 female participants; 333 participants (171 male, 162 female) were in the clinically depressed group. After controlling for confounding factors, we found that clinically depressive symptoms were associated with visceral adiposity in women. Per 1 cm² of visceral adipose tissue area, the risk of being clinically depressed increased 1.006-fold. Similarly, per 1% increase in the ratio of visceral and total adipose tissue area in women, the risk increased 1.028-fold.

CONCLUSIONS

Our large-sample study showed depressive symptoms are associated with intra-abdominal fat and the ratio of visceral and total adipose area in women, after controlling for confounding factors including BMI, hypertension, and diabetes.

Integrated Analysis Reveals Altered Lipid and Glucose Metabolism and Identifies NOTCH2 as a Biomarker for Parkinson's Disease Related Depression

Depression is a common comorbidity in Parkinson's disease (PD) but is underdiagnosed. We aim to investigate the altered metabolic pathways of Parkinson's disease-related depression (PDD) in plasma and to identify potential biomarkers for clinical diagnosis. Consecutive patients with PD were recruited, clinically assessed, and patients with PDD identified. Fasting plasma samples were collected from 99 patients and differentially expressed metabolites and proteins between patients with PDD and PD were identified using non-targeted liquid chromatography-mass spectrometry (LC-MS)-based metabolomics and tandem mass tag (TMT)-based proteomics analysis, followed by an integrated analysis. Based on the above results, enzyme-linked immune sorbent assay (ELISA) tests were then performed to identify potential biomarkers for PDD. In clinics, patients with PDD suffered less hypertension and had lower serum low-density lipoprotein cholesterol and apolipoprotein B levels when compared to the other patients with PD. A total of 85 differentially expressed metabolites were identified in metabolomics analysis. These metabolites were mainly lipids and lipid-like molecules, involved in lipid and glucose metabolic pathways. According to proteomics analysis, 17 differentially expressed proteins were identified, and 12 metabolic pathways were enriched, which were predominantly related to glucose metabolism. Integrated analysis indicated that altered lipid and glucose metabolism in PDD may induce cellular injury through oxidative stress. Additionally, plasma levels of several proteins were confirmed to be significantly altered and correlated with depressive severity. NOTCH2 may be a potential blood biomarker for PDD, with an optimal cut-off point of 0.91 ng/ml, a sensitivity value of 95.65%, and a specificity value of 81.58%. Depressive symptoms are associated with lipid and glucose metabolism in patients with PD and NOTCH2 may be a potential blood biomarker for the clinical diagnosis of PDD.

Depression and Handgrip Strength Among U.S. Adults Aged 60 Years and Older from NHANES 2011-2014

OBJECTIVES

Sarcopenia is a gradual loss of muscle mass and strength that occurs with aging. This muscle deterioration is linked to increased morbidity, disability, and other adverse outcomes. Although reduced handgrip strength can be considered a marker of sarcopenia and other aging-related decline in the elderly, there is limited research on this physical health problem in at-risk groups with common biopsychosocial conditions such as depression. Our primary objective was to ascertain level of combined handgrip strength and its relationship with depression among adults aged 60 years and older.

DESIGN

Unadjusted and adjusted linear regression models were conducted with a cross-sectional survey dataset.

SETTING

Secondary dataset from the 2011-2014 National Health and Nutrition Examination Survey (NHANES).

PARTICIPANTS

Community-dwelling, non-institutionalized adults ≥60 years old (n=3,421).

MEASUREMENTS

The predictor variables included a positive screen for clinically relevant depression (referent=PHQ-9 score <10). The criterion variable of combined handgrip strength (kg) was determined using a dynamometer.

RESULTS

Mean age and BMI were 69.9 years (51.5% female) and 28.8 kg/m2, respectively. Mean combined handgrip strength in the overall cohort was 73.5 and 46.6 kg in males and females, respectively. Three hundred thirty-six (9.8%) reported symptoms of depression. In unadjusted and fully adjusted models, depression was significantly associated with reduced handgrip strength (B = -0.26±0.79 and B = -0.19±0.08, respectively; p<0.001).

CONCLUSION

Our findings demonstrate handgrip strength has a significant inverse association with depression. Future longitudinal studies should investigate the causal processes and potential moderators and mediators of the relationships between depression and reduced handgrip strength. This information may further encourage the use of depression and handgrip strength assessments and aid in the monitoring and implementation of health care services that address both physical and mental health limitations among older adult populations.

High blood glucose levels are associated with higher risk of colon cancer in men: a cohort study

Background

High levels of blood glucose are thought to be associated with colorectal cancer (CRC) and hyperinsulinemia, an interstage in the development of CRC. The purpose of this study was to examine associations between incident CRC and blood glucose; plasma insulin; and the homeostasis model assessment for insulin resistance (HOMA2-IR), respectively, and to determine whether these associations were dependent on sex and cancer site.

Methods

The Malmö Diet and Cancer cardiovascular cohort comprises 6103 individuals. During 81,781 person-years of follow-up, 145 cases of CRC were identified. The hazard ratio of measured blood glucose and plasma insulin and calculated HOMA2-IR were estimated with Cox proportional hazard regression.

Results

An association was found between high levels of blood glucose and risk of CRC (HR: 1.72 for the highest compared with the lowest quartile; 95% CI: 1.05, 2.84; p_trend = 0.044), and colon cancer (HR: 1.70 for the highest compared with the lowest quartile; 95% CI: 0.87, 3.33; p_trend = 0.032). In men, an association was found between blood glucose and CRC (HR: 2.80 for the highest compared with the lowest quartile; 95% CI: 1.37, 5.70; p_trend = 0.001), and colon cancer (HR: 4.48 for the highest compared with the lowest quartile; 95% CI: 1.27, 15.84; p_trend = 0.007), but this was not found in women. No associations between plasma insulin, or HOMA2-IR, and CRC, were found.

Conclusion

High levels of blood glucose in men are associated with risk of colon cancer. The findings contribute to facilitating to identify those most in need of prevention and screening.

Association between suicidal behaviour and impaired glucose metabolism in depressive disorders

BACKGROUND

Disturbances in lipid metabolism have been linked to suicidal behaviour, but little is known about the association between suicide risk and abnormal glucose metabolism in depression. Hyperglycaemia and hyperinsulinaemia may increase the risk of depression and also the risk for suicide, we therefore studied associations between suicidal behaviour and disturbances in glucose metabolism in depressive patients who had been referred to depression nurse case managers.

METHODS

Patients aged 35 years and older (N = 448, mean age 51 years) who were experiencing a new depressive episode, who were referred to depression nurse case managers in 2008-2009 and who scored ≥10 on the Beck Depression Inventory were enrolled in this study. The study was conducted in municipalities within the Central Finland Hospital District (catchment area of 274 000 inhabitants) as part of the Finnish Depression and Metabolic Syndrome in Adults study. The patients' psychiatric diagnoses and suicidal behaviour were confirmed by the Mini-International Neuropsychiatric Interview. Blood samples, for glucose and lipid determinations, were drawn from participants after 12 h of fasting, which was followed by a 2-hour oral glucose tolerance test (OGTT) when blood was drawn at 0 and 2 h. Insulin resistance was measured by the Quantitative Insulin Sensitivity Check Index (QUICKI) method.

RESULTS

Suicidal ideation (49 %) and previous suicide attempts (16 %) were common in patients with major depressive disorder or dysthymia. Patients with depression and suicidal behaviour had higher blood glucose concentrations at baseline and at 2 hours in the OGTT. Glucose levels associated positively with the prevalence of suicidal behaviour, and the linearity was significant at baseline (p for linearity: 0.012, adjusted for age and sex) and for 2-hour OGTT glucose (p for linearity: 0.004, adjusted for age and sex). QUICKI levels associated with suicidal behavior (p for linearity across tertiles of QUICKI: 0.026). Total and LDL cholesterol and triglyceride levels were also higher in those patients with suicidal behaviour. Multivariate analysis revealed that blood glucose levels, BDI scores and antidepressive medications associated with suicidal behaviour.

CONCLUSION

Insulin resistance and disturbances in glucose and lipid metabolism may be more common in middle-aged depressive patients with suicidal behaviour.

Sarcopenic obesity and risk of new onset depressive symptoms in older adults: English Longitudinal Study of Ageing

Background:

We examined the role of sarcopenic obesity as a risk factor for new-onset depressive symptoms over 6-year follow-up in a large sample of older adults.

Methods:

The sample comprised 3862 community dwelling participants (1779 men, 2083 women; mean age 64.6±8.3 years) without depressive symptoms at baseline, recruited from the English Longitudinal Study of Ageing. At baseline and 4-year follow-up, handgrip strength (kg) of the dominant hand was assessed using a hand-held dynamometer, as a measure of sarcopenia. The outcome was new onset depressive symptoms at 6-year follow-up, defined as a score of ⩾4 on the 8-item Centre of Epidemiological Studies Depression scale. Sarcopenic obesity was defined as obese individuals (body mass index ⩾30 kg m⁻²) in the lowest tertile of sex-specific grip strength (<35.3 kg men; <19.6 kg women).

Results:

Using a multivariable logistic regression model, the risk of depressive symptoms was greatest in obese adults in the lowest tertile of handgrip strength (odds ratio (OR), 1.79, 95% confidence interval (CI), 1.10, 2.89) compared with non-obese individuals with high handgrip strength. Participants who were obese at baseline and had a decrease of more than 1 s.d. in grip strength over 4-year follow-up were at greatest risk of depressive symptoms (OR=1.97, 95% CI, 1.22, 3.17) compared with non-obese with stable grip strength.

Conclusions:

A reduction in grip strength was associated with higher risk of depressive symptoms in obese participants only, suggesting that sarcopenic obesity is a risk factor for depressive symptoms.

Subjective depressive symptoms and metabolic syndrome among the general population

OBJECTIVE

The evidence of the association between depression and metabolic syndrome is increasing, but the existence of sex differences in this association remains controversial. The aim of this study was to investigate the association between subjective depressive symptoms and metabolic syndrome and each of its components by sex in the Korean population.

METHODS

The study sample comprised 15,073 men and 15,034 women who underwent routine health examinations. They completed the Beck Depression Inventory for depressive symptoms, and medical examinations provided data regarding metabolic syndrome. Adjustments for age, marriage, cigarette smoking, alcohol use, exercise, education, cancer, stroke, angina, and thyroid disease were performed. The association between depressive symptoms and metabolic syndrome and each of its components was analyzed by multiple logistic regression.

RESULTS

In women, depressive symptoms were associated with metabolic syndrome (OR=1.35, 95% CI=1.11-1.64, p=0.002) and the high-density lipoprotein cholesterol component (OR=1.26, 95% CI=1.09-1.46, p=0.002) of metabolic syndrome. There was also an association between the severity of depressive symptoms and metabolic syndrome in women (OR=1.046, 95% CI=1.002-1.091, p=0.039). In men, depressive symptoms were inversely associated with the hypertension component of metabolic syndrome (OR=0.73, 95% CI=0.58-0.91, p=0.005).

CONCLUSIONS

Subjective depressive symptoms were associated with metabolic syndrome only in women. Further research should consider sex differences and dyslipidemia.

Depression and type 2 diabetes: a causal association?

There is a controversy regarding whether depression and type 2 diabetes are causally linked. To assess this issue, we review key findings for the association between depression and diabetes, and its underlying mechanisms. Findings from meta-analyses of cohort studies show a modestly sized bidirectional association between depression and type 2 diabetes (ie, depression predicts diabetes onset and diabetes predicts future depression). However, depression-related biological alterations in the hypothalamic-pituitary-adrenal cortex axis and the sympathetic nervous system, and subclinical inflammation, are not consistently linked with increased diabetes risk. The evidence for an association between depression and glycaemic traits (eg, glucose, insulin, insulin sensitivity, and insulin secretion) is also mixed. Diabetes increases the risk of depression to the same extent as do other chronic disorders (eg, cardiac diseases, osteoarthritis, lung disease, and poor hearing). At present, the available evidence suggests that pathophysiological changes preceding the onset of type 2 diabetes might not cause depression, nor might depression directly increase the risk of developing type 2 diabetes. Despite insufficient robust causal evidence, treating physicians should be aware of the co-occurrence of depression and type 2 diabetes.

Mediterranean dietary pattern and depression: the PREDIMED randomized trial

BACKGROUND

A few observational studies have found an inverse association between adherence to a Mediterranean diet and the risk of depression. Randomized trials with an intervention based on this dietary pattern could provide the most definitive answer to the findings reported by observational studies. The aim of this study was to compare in a randomized trial the effects of two Mediterranean diets versus a low-fat diet on depression risk after at least 3 years of intervention.

METHODS

This was a multicenter, randomized, primary prevention field trial of cardiovascular disease (Prevención con Dieta Mediterránea (PREDIMED Study)) based on community-dwelling men aged 55 to 80 years and women aged 60 to 80 years at high risk of cardiovascular disease (51% of them had type 2 diabetes; DM2) attending primary care centers affiliated with 11 Spanish teaching hospitals. Primary analyses were performed on an intention-to-treat basis. Cox regression models were used to assess the relationship between the nutritional intervention groups and the incidence of depression.

RESULTS

We identified 224 new cases of depression during follow-up. There was an inverse association with depression for participants assigned to a Mediterranean diet supplemented with nuts (multivariate hazard ratio (HR) 0.78; 95% confidence interval (CI) 0.55 to 1.10) compared with participants assigned to the control group, although this was not significant. However, when the analysis was restricted to participants with DM2, the magnitude of the effect of the intervention with the Mediterranean diet supplemented with nuts did reach statistical significance (multivariate HR = 0.59; 95% CI 0.36 to 0.98).

CONCLUSIONS

The result suggest that a Mediterranean diet supplemented with nuts could exert a beneficial effect on the risk of depression in patients with DM2.

TRIAL REGISTRATION

This trial has been registered in the Current Controlled Trials with the number ISRCTN 35739639.