Metabolic Syndrome, Executive Dysfunction, and Late-Onset Depression: Just a Matter of White Matter?

Associations among inflammation, mental health, and quality of life in adults with metabolic syndrome

BACKGROUND

Metabolic syndrome (MetS), a pro-inflammatory state, has become increasingly common worldwide and is a major risk factor for type 2 diabetes mellitus and cardiovascular disease. Recently, studies on the relationships among inflammation, mental health, quality of life, and other diseases have been conducted.

METHODS

We investigated the relationship between serum high-sensitivity C-reactive protein (hs-CRP) levels, as an indicator of inflammation, and the quality of life and psychiatric symptoms of Korean adults with MetS. The analysis used data from the Korean National Health and Nutrition Examination Survey, a cross-sectional survey of Korean civilians conducted from January to December 2015. Data from 1600 participants were analyzed in this study. Quality of life was assessed using the EuroQol 5-dimension (EQ-5D) instrument.

RESULTS

Serum hs-CRP levels showed a significant inverse correlation with the EQ-5D index of the overall quality of life. High serum hs-CRP levels were positively associated with mobility problems and suicidal ideation in adults with MetS (multivariate-adjusted odds ratio [OR] 1.66, 95% confidence interval [CI] 1.03-2.66, p = 0.036; and multivariate-adjusted OR 2.48, 95% CI 1.23-4.99, p = 0.011).

CONCLUSIONS

These findings suggest that the elevated inflammatory status in MetS is associated with decreased quality of life and mental health problems. Further prospective studies are needed to confirm the impact of inflammation on the quality of life and mental health of adults with MetS.

Effect of Metabolic Syndrome on Late-Life Depression: Associations with Disease Severity and Treatment Resistance

BACKGROUND/OBJECTIVES

Metabolic syndrome (MetS) is the co-occurrence of obesity and metabolic derangements. Prior research implicates MetS in prolongation of the course of depression in older adults, but its effect on antidepressant response is unknown in this population. The objective was to determine whether MetS and related metabolic dyscrasias are associated with decreased rate of remission from depression in older adults treated pharmacologically for depression.

DESIGN

Secondary analysis of a randomized controlled trial.

SETTING

Three academic medical centers in North America.

PARTICIPANTS

Adults aged 60 and older (mean age 69.1) with major depressive disorder (MDD) (N = 435).

INTERVENTION

Open-label, protocolized treatment with extended-release venlafaxine for 12 or more weeks.

MEASUREMENTS

Time to remission from depression, with remission defined as a Montgomery-Åsberg Depression Rating Scale (MADRS) score of 10 or less at last two visits.

RESULTS

Two hundred twenty-two participants (51%) met criteria for MetS at baseline; MetS was associated with greater severity (MADRS score) and chronicity of depression at baseline. Remission was achieved in 182 participants (42%). In the unadjusted analysis, MetS was associated with prolonged time to remission (hazard ratio for remission = 0.71, 95% confidence interval = 0.52-0.95), but this relationship was not significant in the adjusted model; greater number of MetS components and lower high-density lipoprotein cholesterol had similar effects. Only diastolic blood pressure (DBP) was a significant predictor of time to remission before and after adjustment, with higher DBP predicting longer time to remission. Insulin sensitivity did not predict time to remission.

CONCLUSION

The presence of MetS in older adults with depression was associated with greater symptom severity and chronicity of depression, which appears to have accounted for the poorer antidepressant response observed in those with MetS. Additionally, our preliminary finding of an association between higher DBP and poorer antidepressant response bears further examination and replication.

Reduced muscle mass in middle-aged depressed patients is associated with male gender and chronicity

OBJECTIVE

Reduced muscle mass is a characteristic finding in sarcopenia, the central element of physical frailty syndrome, and a major cause of physical function decay, morbidity and mortality in the elderly. Studies so far demonstrated reduced muscle mass in depressed patients with an average age over 60years. An open question is whether muscle mass reduction is already observed earlier. Therefore, muscle mass was assessed in middle-aged male and female depressive patients, and the findings were related to indicators of hypothalamus-pituitary adrenal axis activation, lifestyle factors, endocrine and immune measures.

METHODS

Sixty-seven depressed patients (mean age 38.6y; 58.2% female) and 26 healthy volunteers (mean age 40.5y; 61.5% female) were included. Muscle mass, adrenal gland volume, and intra-abdominal adipose tissue were assessed by magnetic resonance tomography. Laboratory parameters included fasting cortisol, pro-inflammatory cytokines, factors constituting the metabolic syndrome, and relative insulin resistance according to the homeostasis model assessment (HOMA-IR).

RESULTS

We found significant effects of depression (F=4.2; P=0.043) and gender (F=182; P<0.001) on muscle mass. Muscle mass was reduced in depressed men compared to healthy men (F=3.4; P=0.044), particularly in those with chronic depression. In contrast, no such association was observed in depressed females. Adrenal gland volume and intra-abdominal fat was increased in depressed men and women, although not significantly. Correlations were observed for muscle mass with the amount of self-reported exercise and depression severity, and for depression severity with self-reported exercise. Further findings comprised lower self-reported activity and higher cortisol concentrations in depressed male and female compared to healthy probands.

CONCLUSIONS

Muscle mass is reduced in middle-aged depressed men, particularly those with chronic disease course. This association is not observed in depressed females, possibly pointing to the role of female sex steroids in maintaining muscle mass. The increase of adrenal gland volume in depressed patients may point to the role of a dysregulated hypothalamus-pituitary-adrenal system. The inverse association of exercise with muscle mass demonstrates the importance of physical activity. Looking at the long term consequences of reduced muscle mass, interventions to preserve and rebuild muscle mass in depression - such as structured exercise interventions - should be recommended.

SIGNIFICANT OUTCOMES

Muscle mass is decreased in male patients with major depressive disorder, particular those with chronic disease course. This difference was not observed in female depressed patients. The extent of muscle mass reduction is correlated to depression severity and inversely to physical activity, pointing to the role of depression associated inactivity. Low muscle mass is a risk factor for physical frailty, therefore interventions aiming at improving physical fitness may be recommended.

LIMITATIONS

Sex steroids were not assessed in the study groups.

Structural and Functional Connectivity of Default Mode Network underlying the Cognitive Impairment in Late-onset Depression

To identify the association between the functional and structural changes of default mode network (DMN) underlying the cognitive impairment in Late-onset depression (LOD), 32 LOD patients and 39 normal controls were recruited and underwent resting-state fMRI, DTI scans, and cognitive assessments. Seed-based correlation analysis was conducted to explore the functional connectivity (FC) of the DMN. Deterministic tractography between FC-impaired regions was performed to examine the structural connectivity (SC). Partial correlation analyses were employed to evaluate the cognitive association of those altered FC and SC. Compared with controls, LOD patients showed decreased FC between DMN and the cingulo-opercular network (CON), as well as the thalamus. Decreased FA and increased RD of these fiber tracts connecting DMN with CON were found in LOD patient. The DMN-CON FC and the FA, RD of the fiber tracts were both significantly correlated with the cognitive performance. Therefore, the cognitive impairment in LOD might be associated with the decreased FC between the DMN and the CON, which probably resulted from the demyelination of the white matter.

Association Between Falls and Brain Subvolumes: Results from a Cross-Sectional Analysis in Healthy Older Adults

Falls are a consequence of gait instability. Cortical and subcortical abnormalities have been associated with gait instability but not yet with falls. This study aims to compare the global and regional brain subvolumes between healthy older fallers and non-fallers. A total of 77 healthy older individuals (23 fallers and 54 non-fallers, 69.8 ± 3.5 years; 45.5 % female) were included in this study using a cross-sectional design. Based on an a priori hypothesis, the following brain subvolumes were quantified from three-dimensional T₁-weighted MRI using FreeSurfer software: total white matter abnormalities, total white matter, total cortical and subcortical gray matter, hippocampus, motor cortex, somatosensory cortex, premotor cortex, prefrontal cortex and parietal cortex volumes. Gait performances were also recorded. Age, sex, body mass index, comorbidities, use of psychoactive drugs, far-distance visual acuity, lower-limb proprioception, depressive symptoms and cognitive scores (Mini-Mental State Examination, Frontal Assessment Battery) were used as covariates. Fallers have more frequently depressive symptoms (P = 0.048), a lower far distance visual acuity (P = 0.026) and a higher coefficient of variation of stride time (P = 0.008) compared to non-fallers. There was a trend to greater subvolumes for the somatosensory cortex (P = 0.093) and the hippocampus (P = 0.060) in the falls group. Multiple logistic regressions showed that subvolumes of the somatosensory cortex and the hippocampus (P < 0.042) were increased in fallers compared to non-fallers, even after adjustment for clinical and brain characteristics. The greater subvolumes of the somatosensory cortex and hippocampus reported in fallers compared to non-fallers suggests a possible brain compensatory mechanism involving spatial navigation and integration of sensory information.

Executive dysfunction assessed by Clock-Drawing Test in older non-demented subjects with metabolic syndrome is not mediated by white matter lesions

AIMS

Metabolic syndrome (MetS) has been associated with greater occurrence of white matter hyperintensities (WMH). It remains uncertain whether MetS as a construct is associated with poorer cognitive performances. This study explores whether MetS is associated with poorer performances in global and domain-specific cognitive tests in older non-demented subjects independently of its individual components, WMH severity and other variables.

METHODS

MetS was diagnosed according to the National Cholesterol Education Program Adult Treatment Panel III definition. Brain magnetic resonance studies (1.5T) were performed. Deep and periventricular WMH were graded using the Fazekas scale. Subjects underwent the Mini-Mental State Examination, the Babcock Short Story Recall test and the Clock-Drawing Test (CDT).

RESULTS

Eighty community-dwellers aged 67-91 years were studied. Subjects with MetS (n = 35) had more severe WMH, and poorer performances on the CDT (P = 0.003) and the Babcock Short Story Recall test (P = 0.027). After multiple adjustment, MetS was inversely associated with CDT scores (B = -1.285; 95% confidence interval = -1.996--0.575; P = 0.001) but not with episodic memory. Results were not affected by WMH severity. Interestingly, none of the individual components of MetS predicted poorer cognitive performances.

CONCLUSIONS

Impairment in executive functions assessed by CDT may represent an early and specific sign of cognitive decline in older individuals with MetS. Future longitudinal studies are needed to better establish the predictive role of MetS on dementia and to demonstrate the possibility of dementia prevention by targeting MetS.