Early neurological and cognitive impairments in subclinical cerebrovascular disease.

BACKGROUND: The subclinical cerebrovascular disease (SCVD) is an important public health problem with demonstrated prognostic significance for stroke, future cognitive decline, and progression to dementia. The earliest possible detection of the silent presence of SCVD in adults at age at risk with normal functioning is very important for both clinical doctors and scientists. MATERIALS AND METHODS: Seventy-seven adult volunteers, recruited during the years 2005-2007, with mean age 58.7 (standard deviation 5.9) years, were assessed by four subtests from the Cambridge Neuropsychological Test Automated Battery (CANTAB)-Eclipse cognitive assessment system. We used a questionnaire survey for the presence of cerebrovascular risk factors (CVRFs) such as arterial hypertension, smoking and dyslipidemia, among others, as well as instrumental (Doppler examination) and neurological magnetic resonance imaging (MRI) procedures. Descriptive statistics, comparison (t-test, Chi-square) and univariate methods were used as followed by multifactor logistic regression and receiver operating characteristics analyses. RESULTS: The risk factor questionnaire revealed nonspecific symptoms in 44 (67.7%) of the subjects. In 42 (64.6%) of all 65 subjects, we found at least one of the conventional CVRFs. Abnormal findings from the extra- and trans-cranial Doppler examination were established in 38 (58.5%) of all studied volunteers. Thirty-four subjects had brain MRI (52.3%), and abnormal findings were found in 12 (35.3%) of them. Two of the four subtests of CANTAB tool appeared to be potentially promising predictors of the outcome, as found at the univariate analysis (spatial working memory 1 [SWM1] total errors; intra-extra dimensional set 1 [IED1] total errors [adjusted]; IED2 total trials [adjusted]). We established that the best accuracy of 82.5% was achieved by a multifactor interaction logistic regression model, with the role CVRF and combined CANTAB predictor "IED total ratio (errors/trials) × SWM1 total errors" (P = 0.006). CONCLUSIONS: Our results have contributed to the hypothesis that it is possible to identify, by noninvasive methods, subjects at age at risk who have mild degree of cognitive impairment and to establish the significant relationship of this impairment with existing CVRFs, nonspecific symptoms and subclinical abnormal brain Doppler/MRI findings. We created a combined neuropsychological predictor that was able to clearly distinguish between the presence and absence of abnormal Doppler/MRI findings. This pilot prognostic model showed a relatively high accuracy of >80%; therefore, the predictors may serve as biomarkers for SCVD in subjects at age at risk (51-65 years).

Contribution of Components of Metabolic Syndrome to Cognitive Performance in Middle-Aged Adults.

INTRODUCTION: Metabolic syndrome (MetS) has been associated with impaired cognition in different cognitive domains. This study investigated the association between MetS and cognitive functioning in middle-aged Bulgarians across different definitions of MetS severity. MATERIAL AND METHODS: Our cross-sectional sample included 112 participants (67 free of MetS and 45 with MetS) with a mean age of 50.04 ± 3.31 years. The following MetS variables were considered-presence of MetS, continuously measured MetS components, dichotomized MetS components, number of MetS components present, and Metabolic Syndrome Severity Score (MSSS). Participants' cognitive performance was assessed using the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Battery (CERAD-NB). We employed multivariate regression models to investigate the associations between different measures of MetS severity and CERAD-NB total and subtest scores. RESULTS: Bivariate analyses showed that the CERAD-NB total score was significantly higher in women, participants with a university degree, those with normal blood pressure, normal waist circumference, and low triglyceride levels, compared with their counterparts. MetS participants had lower CERAD-NB total score (78.87 ± 6.89 vs. 84.97 ± 7.84) and specifically performed poorer on the subtest Word List Recall (7.16 ± 1.52 vs. 7.99 ± 1.52). These findings persisted after controlling for age, gender, and education. Next, generalized linear regression indicated that the CERAD-NB total score was lower in participants with MetS (ß = -4.86; 95% confidence interval [CI]: -7.60, -2.11), those with more MetS components (ß = -8.31; 95% CI: -14.13, -2.50 for fours vs. 0 components) and with an increase in MSSS (ß = -3.19; 95% CI: -4.67, -1.71). Hypertension independently contributed to lower CERAD-NB total score (ß = -4.00; 95% CI: -6.81, -1.19). CONCLUSIONS: Across several definitions, MetS was associated with lower cognitive functioning, and MetS severity appeared to be a better predictor than most MetS components. Recognizing and reducing severity of MetS components might be helpful in supporting cognitive functioning. Further longitudinal research is needed to shed more light on the relationship between MetS and cognitive functioning across the life span.

A feasibility study on the association between residential greenness and neurocognitive function in middle-aged Bulgarians.

Recent research has indicated that exposure to residential vegetation ("greenness") may be protective against cognitive decline and may support the integrity of the corresponding brain structures. However, not much is known about these effects, especially in less affluent countries and in middle-aged populations. In this study, we investigated the associations between greenness and neurocognitive function. We used a convenience sample of 112 middle-aged Bulgarians and two cognitive tests: the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Battery (CERAD-NB) and the Montreal Cognitive Assessment (MoCA). In addition, structural brain imaging data were available for 25 participants. Participants' home address was used to link cognition scores to the normalised difference vegetation index (NDVI), a measure of overall neighbourhood vegetation level (radii from 100 to 1,000 m). Results indicated that higher NDVI was consistently associated with higher CERAD-NB and MoCA scores across radial buffers and adjustment scenarios. Lower waist circumference mediated the effect of NDVI on CERAD-NB. NDVI100-m was positively associated with average cortical thickness across both hemispheres, but these correlations turned marginally significant (P<0.1) after correction for false discovery rate due to multiple comparisons. In conclusion, living in a greener neighbourhood might be associated with better cognitive function in middle-aged Bulgarians, with lower central adiposity partially accounting for this effect. Tentative evidence suggests that greenness might also contribute to structural integrity in the brain regions regulating cognitive functions. Future research should build upon our findings and investigate larger and more representative population groups.

Vascular Risk Factors in Bulgarian Volunteers in Middle Adulthood.

The present study in Bulgarian volunteers aged 45-55 years focuses on the type and frequency of some vascular risk factors (VRF); it analyzes physical data and results of instrumental investigations (ophthalmoscopy, electrocardiography, Doppler sonography) as well as magnetic resonance imaging (MRI). The study participants have neither subjective memory complaints nor previous cerebrovascular and cardiovascular incidents. The neurological examination and the mental status is normal and VRF are not considered to aff ect their normal daily living. The arterial hypertension (I degree), dyslipidemia and increased LDL-cholesterol correlate with the pathological findings from Doppler/MRI. The regression model explains 35% of the dispersion in statistics and correctly classifies 76.8% of the observations as independent prognostic factors for the presence of abnormal findings from Doppler/MRI at the age from 45 to 55 years, which corresponds to subclinical cerebrovascular disease.

Cortisol Correlates with Structural Magnetic Resonance Imaging Parameters in Middle Aged Bulgarian Patients with Metabolic Syndrome: A Pilot Study.

BACKGROUND: There is a dose-dependent relationship between chronically increased cortisol levels and the number of metabolic syndrome (MetS) components. Both cortisol and MetS are linked to various brain abnormalities. AIM: To investigate an association of MetS components and salivary cortisol levels with cortical thickness in middle-aged Bulgarian patients with MetS. MATERIALS AND METHODS: We examined 26 healthy volunteers (mean age 50, 16±3.1 yrs) divided into two groups depending on whether or not they were diagnosed with MetS. Salivary cortisol was sampled and tested at two time points -morning and evening. Cortical thickness measures were obtained from structural T1-images using FreeSurfer software. We performed vertex-wise analysis across entire cortex and for preselected brain regions in frontal, temporal and cingulate cortex partial correlation analysis, accounting for gender. RESULTS: The control group consisted of 12 women; in the MetS group there were 6 men and 8 women. The whole brain analysis showed that waist circumference (WC) was negatively correlated with cortical thickness in rostro-lateral area in left frontal lobe and the right lateral orbito-frontal cortex. Morning cortisol levels, accounting for sex and WC, correlated negatively with thickness in left superior temporal area (r = -0.477, p = 0.039) and entorhinal area (r = -0.465, p = 0.045) and left mediotemporal cortex (r = -0.477, p = 0.038). CONCLUSION: Our pilot study confirmed that WC is associated with brain atrophic changes mainly in the frontal lobe. Our finding that cortisol levels negatively correlate with thinning of the cortex in temporal lobe should be further explored in subsequent study.

Metabolic syndrome severity score: range and associations with cardiovascular risk factors.

INTRODUCTION: Metabolic Syndrome Severity Score (MSSS) is a new clinical prediction rule (CPR) for diagnostic and therapeutic decisions and employs available components (sex, age, race, systolic blood pressure, waistline circumference, high-density lipoprotein, triglycerides and fasting blood glucose). The aim of our work was to perform cross-sectional pilot trial on middle-aged healthy volunteers and patients with metabolic syndrome (MetS) with and without type 2 diabetes mellitus (T2DM) for studying feasibility and implementation of MSSS and its associations with cardiovascular risk factors. MATERIAL AND METHODS: We approached 64 eligible participants from Bulgaria. The MSSS values, together with demographic, anthropometric, medical history, laboratory findings, CVD risk factors, QRISK2 score for 10-year cardiovascular risk and predicted heart age, were analysed. Descriptive statistics with tests for comparison (e.g., t-test, χ2) between groups as well as ANOVA and logistic regression were applied. RESULTS: We analysed data from 56 participants (aged 50.11 ±3.43 years). The MSSS was higher in MetS patients (including 6 T2DM patients) than in controls (n = 29; 51.8%) presented as percentiles (69.97% and 34.41%, respectively) and z-scores (0.60 and -0.45, respectively) (p < 0.05). The logistic regression model of MSSS indicated a positive association with MetS/T2DM cases (correctness > 85%, p < 0.01). For further validation purposes, positive correlations of MSSS with CVD risk factor as diastolic blood pressure (Rho = 0.399; p < 0.003) and QRISK2 score (Rho = 0.524; p < 0.001) or predicted heart age (Rho = 0.368; p < 0.007) were also found. CONCLUSIONS: The pilot study of MSSS in Bulgaria indicated feasibility and consistency of its implementation among patients with metabolic syndrome and/or T2DM and healthy volunteers.