Brain tissue volumes and small vessel disease in relation to the risk of mortality

Mediation analysis of brain magnetic resonance imaging variables with all-cause and cardiovascular disease-specific mortalities in persons with type 2 diabetes

AIM

Glucose variation (GV) has emerged as a predictor of morbidity and mortality in persons with diabetes. However, no study has examined whether brain magnetic resonance imaging (MRI) variables mediated the association between mortality and GV.

MATERIALS AND METHODS

This study was a retrospective cohort comprising 3,961 individuals with type 2 diabetes (T2D), whose electronic medical records were retrieved from a medical center between January 2001 and October 2021. GV was quantified using coefficient of variation of fasting plasma glucose (FPG-CV) and glycated hemoglobin (HbA1c). The MRI variables included the presence or absence of cerebrovascular abnormality and white matter hyperintensity (WMH). All deaths and deaths resulting from expanded cardiovascular disease (CVD) were identified through annual record linkage with National Death Datasets. Cox proportional hazards models were applied to evaluate associations of MRI variable or GV with mortality. Mediation analyses were performed to assess the relative contributions of MRI variables for GV on mortality.

RESULTS

Among 3,961 patients, 2,114 patients (53.4%) had cerebrovascular abnormality and 1,888 patients (47.7%) had WMH. The results showed cerebrovascular abnormality and WMHs were significantly associated with all-cause and expanded CVD mortality after considering GV. The largest mediated effects of GV on all-cause and expanded CVD mortality were observed by cerebrovascular abnormality (5.26% and 8.49%, respectively).

CONCLUSIONS

Our study suggests cerebrovascular abnormality and WMHs are important predictors of mortality in patients with T2D after considering GV. In addition, MRI variables of cerebrovascular abnormality expressed weak but significant mediation effect on the associations between GV and mortality.

Baseline and Longitudinal MRI Markers Associated With 16-Year Mortality in Patients With Cerebral Small Vessel Disease

BACKGROUND AND OBJECTIVES

Information on whether small vessel disease (SVD) reduces life expectancy is limited. Moreover, the excess mortality risk attributed specifically to SVD compared with controls from the general population has not been evaluated. This study aimed to investigate the baseline and progression of MRI markers of SVD associated with mortality in a 16-year follow-up cohort study and to determine the excess long-term mortality risk of patients with SVD.

METHODS

Participants with SVD from the Radboud University Nijmegen Diffusion Tensor and Magnetic Resonance Imaging Cohort (RUN DMC) study (with MRI assessments in 2006, 2011, 2015, and 2020) were followed until their death or December 1, 2021. Adjusted Cox regression analyses and linear mixed-effect regression models were used to investigate the association between MRI markers of SVD and mortality. The excess mortality risk of SVD was calculated by comparing mortality data of the RUN DMC study with the general population matched by sex, age, and calendar year.

RESULTS

200 of 503 (39.9%) participants died during a follow-up period of 15.9 years. Cause of death was available for 182 (91%) participants. Baseline white matter hyperintensity volume (HR 1.3 per 1-SD increase [95% CI 1.1-1.5], p = 0.010), presence of lacunes (1.5 [95% CI 1.1-2.0], p = 0.008), mean diffusivity (HR 1.1 per 1-SD increase [95% CI 1.1-1.2], p = 0.001), and total brain volume (HR 1.5 per 1-SD decrease [95% CI 1.3-1.9], p < 0.001) were associated with all-cause mortality after adjusting for age, sex, and vascular risk factors. Total brain volume decrease over time was associated with all-cause mortality after adjusting for age, sex, and vascular risk factors (HR 1.3 per 1-SD decrease [95% CI 1.1-1.7], p = 0.035), and gray matter volume decrease remained significant after additionally adjusting for its baseline volume (1.3 per 1-SD decrease [1.1-1.6], p = 0.019). Participants with a Fazekas score of 3, presence of lacunes, or lower microstructural integrity had an excess long-term mortality risk (21.8, 15.7, 10.1 per 1,000 person-years, respectively) compared with the general population.

DISCUSSION

Excess long-term mortality risk only exists in patients with severe SVD (Fazekas score of 3, presence of lacunes, or lower microstructural integrity). This could help in assisting clinicians to predict the clinical outcomes of patients with SVD by severity.

Mortality Outcomes in a Large Population with and without Covert Cerebrovascular Disease

Covert cerebrovascular disease (CCD) is frequently reported on neuroimaging and associates with increased dementia and stroke risk. We aimed to determine how incidentally-discovered CCD during clinical neuroimaging in a large population associates with mortality. We screened CT and MRI reports of adults aged ≥50 in the Kaiser Permanente Southern California health system who underwent neuroimaging for a non-stroke clinical indication from 2009-2019. Natural language processing identified incidental covert brain infarcts (CBI) and/or white matter hyperintensities (WMH), grading WMH as mild/moderate/severe. Models adjusted for age, sex, ethnicity, multimorbidity, vascular risks, depression, exercise, and imaging modality. Of n=241,028, the mean age was 64.9 (SD=10.4); mean follow-up 4.46 years; 178,554 (74.1%) had CT; 62,474 (25.9%) had MRI; 11,328 (4.7%) had CBI; and 69,927 (29.0%) had WMH. The mortality rate per 1,000 person-years with CBI was 59.0 (95%CI 57.0-61.1); with WMH=46.5 (45.7-47.2); with neither=17.4 (17.1-17.7). In adjusted models, mortality risk associated with CBI was modified by age, e.g. HR 1.34 [1.21-1.48] at age 56.1 years vs HR 1.22 [1.17-1.28] at age 72 years. Mortality associated with WMH was modified by both age and imaging modality e.g., WMH on MRI at age 56.1 HR = 1.26 [1.18-1.35]; WMH on MRI at age 72 HR 1.15 [1.09-1.21]; WMH on CT at age 56.1 HR 1.41 [1.33-1.50]; WMH on CT at age 72 HR 1.28 [1.24-1.32], vs. patients without CBI or without WMH, respectively. Increasing WMH severity associated with higher mortality, e.g. mild WMH on MRI had adjusted HR=1.13 [1.06-1.20] while severe WMH on CT had HR=1.45 [1.33-1.59]. Incidentally-detected CBI and WMH on population-based clinical neuroimaging can predict higher mortality rates. We need treatments and healthcare planning for individuals with CCD.

Development and validation of a predictive model for white matter lesions in young- and middle-aged people

BACKGROUND

White matter lesion (WML) is an age-related disorder associated with stroke and cognitive impairment. This study aimed to investigate the risk factors and build a predictive model of WML in young- and middle-aged people.

METHODS

We performed a second analysis of the data from the Dryad Digital Repository. We selected those people who are <60 years old and randomly divided them into the training group and the validation group. We investigated the risk factors of WML in the training group with logistic regression analysis and built a prediction nomogram based on multivariate logistic regression analysis; finally, the performance of the prediction nomogram was evaluated for discrimination, accuracy, and clinical utility.

RESULTS

There were 308 people in the training group and 723 people in the validation group. Multivariate regression analysis showed that the age (OR = 1.49, 95% CI: 1.31-1.70), diastolic blood pressure (OR = 1.02, 95% CI: 1.00-1.03), carotid plaque score (OR = 1.31, 95% CI: 1.14-1.50), female gender (OR = 2.27, 95% CI: 1.56-3.30), and metabolic syndrome (OR = 2.12, 95% CI: 1.22-3.70) were significantly associated with white matter lesions. The area under the curve value (AUC) of the receiver operating curve (ROC) was 0.734 for the training group and 0.642 for the validation group. The calibration curve and clinical impact curve showed that the prediction nomogram has good accuracy and clinical application value.

CONCLUSION

Age, diastolic blood pressure, carotid plaque score, female gender, and metabolic syndrome were risk factors in young- and middle-aged people <60 years old with WML, and the nomogram based on these risk factors showed good discrimination, accuracy, and clinical utility.

Small vessel disease is associated with later onset of major adverse cardiovascular events after acute cervicocerebral artery dissection

BACKGROUND

Cerebral small vessel disease (CSVD) is common among the elderly and has been associated with an increased risk of major adverse cardiac events (MACE) and increased risk of long-term disability. Little is known whether CSVD affects outcomes after cervicocerebral artery dissection (CAD), which predominantly affects younger patients. Specifically, there is a paucity as to whether CSVD increases the risk of MACE after CAD and whether this risk is different for early versus late events.

METHODS

We retrospectively analyzed 140 consecutive patients with acute CAD. We determined CSVD on MRI using the STRIVE criteria and calculated the CSVD sum score based on the individual CSVD components. For statistical analysis the CSVD burden was dichotomized to mild (score 0-1) versus severe (score 2-4). The primary outcome of interest was the 6-month MACE risk. Secondary outcomes of interest were early versus late MACE, stroke at presentation, and good 90-day outcome (modified Rankin Scale score 0-2).

RESULTS

There was no difference in overall MACE between subjects when stratified by CSVD burden (10.1% versus 9.8%, Log-rank P = 0.953). We found that patients with severe CSVD had significantly more late MACE as compared to mild CSVD (9.8% versus 1.1%, P = 0.024). There was no significant difference in the prevalence of stroke at the time of CAD diagnosis (50.6% versus 47.1%, P = 0.690) and the 90-day disability-free survival in subjects with mild versus severe CSVD (93.7% versus 91.7%, P = 0.729).

CONCLUSION

Severe CSVD burden was associated with a significantly greater risk of late MACE. CSVD assessment in CAD patients may aid risk stratification and treatment optimization.

Targeting cerebral small vessel disease to promote healthy aging: Preserving physical and cognitive functions in the elderly

Cerebral small vessel disease (SVD), which is highly age-related, is the most common neuroimaging finding in community-dwelling elderly individuals. In addition to increasing the risk of dementia and stroke, SVD is associated with cognitive and physical (particularly gait speed) functional impairments in the elderly. Here, we provide evidence suggesting covert SVD, e.g. without clinically evident stroke or dementia, as a critical target to preserve the functional ability that enables well-being in older age. First, we discuss the relationship between covert SVD and geriatric syndrome. SVD lesions found in non-demented, stroke-free elderly are actually not "silent" but are associated with accelerated age-related functional decline. We also review the brain structural and functional abnormalities associated with covert SVD and the possible mechanisms underlying their contributions to SVD-related cognitive and physical functional impairments. Finally, we reveal current data, though limited, on the management of elderly patients with covert SVD to prevent SVD lesion progression and functional decline. Although it is important in aging health, covert SVD is still under-recognized or misjudged by physicians in both neurological and geriatric professions. Improving the acknowledgment, detection, interpretation, and understanding of SVD would be a multidisciplinary priority to maintain cognitive and physical functions in the elderly. The dilemmas and future directions of clinical practice and research for the elderly with covert SVD are also included in the present review.

Associations of Life's Simple 7 with cerebral white matter hyperintensities and microstructural integrity: UK Biobank cohort study

BACKGROUND AND PURPOSE

The American Heart Association Life's Simple 7 (LS7) metric was used to define optimal cardiovascular and brain health, but the associations with macrostructural hyperintensities and microstructural white matter damage are unclear. The objective was to determine the association of LS7 ideal cardiovascular health factors with macrostructural and microstructural integrity.

METHOD

A total of 37,140 participants with available LS7 and imaging data from UK Biobank were included in this study. Linear associations were implemented to examine the associations of LS7 score and subscores with white matter hyperintensity load (WMH) (WMH volume normalized by total white matter volume and logit-transformed) and diffusion imaging indices (fractional anisotropy [FA], mean diffusivity, orientation dispersion index [OD], intracellular volume fraction, isotropic volume fraction [ISOVF]).

RESULTS

In individuals (mean age 54.76 years; 19,697 females, 52.4%), higher LS7 score and subscores were strongly associated with lower WMH and microstructural white matter injury, including OD, ISOVF, FA. Both interaction analyses and stratified analyses of LS7 score and subscores with age and sex showed a strong association with microstructural damage markers, with remarkable age and sex differences. The association of OD was pronounced in females and populations younger than 50 years and FA, mean diffusivity and ISOVF were pronounced in males and populations older than 50 years.

CONCLUSION

These findings suggest that healthier LS7 profiles are associated with better profiles of both macrostructural and microstructural markers of brain health, and indicate that ideal cardiovascular health is associated with improved brain health.

Regional Cerebral Small Vessel Disease (rCSVD) Score: A clinical MRI grading system validated in a stroke cohort

BACKGROUND

Current methods for quantitative assessment of cerebral small vessel disease (CSVD) ignore critical aspects of the disease, namely lesion type and regionality. We developed and tested a new scoring system for CSVD, "regional Cerebral Small Vessel Disease" (rCSVD) based on regional assessment of magnetic resonance imaging (MRI) features.

METHODS

141 patients were retrospectively included with a derivation cohort of 46 consecutive brain MRI exams and a validation cohort of 95 patients with known cerebrovascular disease. We compared the predictive value of rCSVD against existing scoring methods. We determined the predictive value of rCSVD score for all-cause mortality and recurrent strokes.

RESULTS

46 (44 male) veteran patients (age: 66-93 years), were included for derivation of the rCSVD score. A non-overlapping validation cohort consisted of 95 patients (89 male; age: 34-91 years) with known cerebrovascular disease were enrolled. Based on ROC analysis with comparison of AUC (Area Under the Curve), "rCSVD" score performed better compared to "total SVD score" and Fazekas score for predicting all-cause mortality (0.75 vs 0.68 vs 0.69; p = 0.046). "rCSVD" and total SVD scores were predictive of recurrent strokes in our validation cohort (p-values 0.004 and 0.001). At a median of 5.1 years (range 2-17 years) follow-up, Kaplan-Meier survival analysis demonstrated an rCSVD score of 2 to be a significant predictor of all-cause-mortality.

CONCLUSION

"rCSVD" score can be derived from routine brain MRI, has value in risk stratification of patients at risk of CSVD, and has potential in clinical trials once fully validated in a larger patient cohort.

Association of Ischemic Imaging Phenotype With Progression of Brain Atrophy and Cerebrovascular Lesions on MRI: The SMART-MR Study

OBJECTIVE

To investigate the association of silent vascular lesions, imaging negative ischemia, and symptomatic cerebrovascular disease with long-term progression of brain atrophy and cerebrovascular lesions in patients with arterial disease.

METHODS

Within the SMART-MR study, stroke status of participants at baseline was classified as no cerebrovascular disease (reference group, n=829), symptomatic cerebrovascular disease (n=206), silent vascular lesion (n=157), and imaging negative ischemia (n=90) based upon clinical and MRI findings. Using linear mixed models, changes in brain and white matter hyperintensity (WMH) volumes at baseline and during 12 years of follow-up were studied in stroke classifications. Relative risks were estimated for new infarcts during follow-up associated with stroke classifications. Analyses were adjusted for age, sex, cardiovascular risk factors, and medications.

RESULTS

Symptomatic cerebrovascular disease associated with 0.35 SDs (95%CI 0.24-0.47) smaller brain volume and 0.61 SDs (95%CI 0.48-0.74) larger WMH volume at baseline, and increased risk for new infarcts during follow-up (risk ratio (RR) 2.89; 95%CI 2.00-4.16). Silent vascular lesions associated with 0.15 SDs (95%CI 0.01-0.88) smaller brain volume, 0.02 SDs (95%CI 0.01-0.03) steeper brain atrophy slope, and 0.48 SDs (95%CI 0.32-0.64) larger WMH volume at baseline, in addition to increased risk for lacunes (RR 2.08; 95%CI 1.48-2.94). Individuals with imaging negative ischemia had increased risk for cortical infarcts (RR=2.88; 95%CI 2.17-3.82).

CONCLUSIONS

Patients with symptomatic cerebrovascular disease, silent vascular lesions, or imaging negative ischemia have different course of brain volume loss and cerebrovascular lesions development. These findings may have implications for future stroke risk and dementia and need further investigation.

Association Between Brain Volumes and Patterns of Physical Activity in Community-Dwelling Older Adults

BACKGROUND

Larger brain volumes are often associated with more free-living physical activity (PA) in cognitively normal older adults. Yet, whether greater brain volumes are associated with more favorable (less fragmented) PA patterns, and whether this association is stronger than with total PA, remains unknown.

METHODS

Brain magnetic resonance imaging and wrist-worn accelerometer data were collected in 301 participants (mean age = 77 [SD = 7] years, 59% women) enrolled in the Baltimore Longitudinal Study of Aging. Linear regression models were fit to examine whether brain volumes (cc) were cross-sectionally associated with: (a) total daily PA minutes and (b) activity fragmentation (mean number of PA bouts / total PA minutes × 100). Sensitivity analyses were conducted by adjusting for counterpart PA variables (eg, fragmentation covariate included in the PA minutes model).

RESULTS

Greater white matter volumes in the parietal and temporal lobes were associated with higher daily PA minutes (2.6 [SE = 1.0] and 3.8 [0.9] min/day, respectively; p < .009 for both) after adjusting for demographics, behavioral factors, medical conditions, gait speed, apolipoprotein E e4 status, and intracranial volume. Greater temporal white matter volume was associated with lower fragmentation (-0.16% [0.05], p = .003). In sensitivity analyses, observed associations between brain volumes and daily PA minutes remained significant while associations with fragmentation no longer remained significant.

CONCLUSIONS

Our results suggest white matter brain structure in cognitively normal older adults is associated with the total amount of PA and, to a lesser extent, the PA accumulation patterns. More work is needed to elucidate the longitudinal relationship between brain structure and function and PA patterns with aging.

Does vascular stiffness predict white matter hyperintensity burden in ischemic heart disease with preserved ejection fraction?

The survival rate of patients with ischemic heart disease (IHD) is increasing. However, survivors experience increased risk for neurological complications. The mechanisms for this increased risk are unknown. We tested the hypothesis that patients with IHD have greater carotid and cerebrovascular stiffness, and these indexes predict white matter small vessel disease. Fifty participants (age, 40-78 yr), 30 with IHD with preserved ejection fraction and 20 healthy age-matched controls, were studied using ultrasound imaging of the common carotid artery (CCA) and middle cerebral artery (MCA), as well as magnetic resonance imaging (T1, T2-FLAIR), to measure white matter lesion volume (WMLv). Carotid β-stiffness provided the primary measure of peripheral vascular stiffness. Carotid-cerebral pulse wave transit time (ccPWTT) provided a marker of cerebrovascular stiffness. Pulsatility index (PI) and resistive index (RI) of the MCA were calculated as measures of downstream cerebrovascular resistance. When compared with controls, patients with IHD exhibited greater β-stiffness [8.5 ± 3.3 vs. 6.8 ± 2.2 arbitrary units (AU); P = 0.04], MCA PI (1.1 ± 0.20 vs. 0.98 ± 0.18 AU; P = 0.02), and MCA RI (0.66 ± 0.06 vs. 0.62 ± 0.07 AU; P = 0.04). There was no difference in WMLv between IHD and control groups (0.95 ± 1.2 vs. 0.86 ± 1.4 mL; P = 0.81). In pooled patient data, WMLv correlated with both β-stiffness (R = 0.34, P = 0.02) and cerebrovascular ccPWTT (R = -0.43, P = 0.02); however, β-stiffness and ccPWTT were not associated (P = 0.13). In multivariate analysis, WMLv remained independently associated with ccPWTT (P = 0.02) and carotid β-stiffness (P = 0.04). Patients with IHD expressed greater β-stiffness and cerebral microvascular resistance. However, IHD did not increase risk of WMLv or cerebrovascular stiffness. Nonetheless, pooled data indicate that both carotid and cerebrovascular stiffness are independently associated with WMLv.NEW & NOTEWORTHY This study found that patients with ischemic heart disease (IHD) with preserved ejection fraction and normal blood pressures exhibit greater carotid β-stiffness, as well as middle cerebral artery pulsatility and resistive indexes, than controls. White matter lesion volume (WMLv) was not different between vascular pathology groups. Cerebrovascular pulse wave transit time (ccPWTT) and carotid β-stiffness independently associate with WMLv in pooled participant data, suggesting that regardless of heart disease history, ccPWTT and β-stiffness are associated with structural white matter damage.

White matter hyperintensities mediate the association of nocturnal blood pressure with cognition

OBJECTIVE

To test the hypotheses that hypertension and nocturnal blood pressure are related to white matter hyperintensity (WMH) volume, an MRI marker of small vessel cerebrovascular disease, and that WMH burden statistically mediates the association of hypertension and dipping status with memory functioning, we examined the relationship of hypertension and dipping status on WMH volume and neuropsychological test scores in middle-aged and older adults.

METHODS

Participants from the community-based Maracaibo Aging Study received ambulatory 24-hour blood pressure monitoring, structural MRI, and neuropsychological assessment. Four hundred thirty-five participants (mean ± SD age 59 ± 13 years, 71% women) with available ambulatory blood pressure, MRI, and neuropsychological data were included in the analyses. Ambulatory blood pressure was used to define hypertension and dipping status (i.e., dipper, nondipper, and reverse dipper based on night/day blood pressure ratio <0.9, 0.9-1, and >1, respectively). Outcome measures included regional WMH and memory functioning derived from a neuropsychological test battery.

RESULTS

The majority of the participants (59%) were hypertensive. Ten percent were reverse dippers, and 40% were nondippers. Reverse dipping in the presence of hypertension was associated with particularly elevated periventricular WMH volume (F 2,423 = 3.78, p = 0.024) and with lowered memory scores (F 2,423 = 3.911, p = 0.021). Periventricular WMH volume mediated the effect of dipping status and hypertension on memory (β = -4.1, 95% confidence interval -8.7 to -0.2, p < 0.05).

CONCLUSION

Reverse dipping in the presence of hypertension is associated with small vessel cerebrovascular disease, which, in turn, mediates memory functioning. These results point toward reverse dipping as a marker of poor nocturnal blood pressure control, particularly among hypertensive individuals, with potentially pernicious effects on cerebrovascular health and associated cognitive function.

Brain atrophy in cerebral small vessel diseases: Extent, consequences, technical limitations and perspectives: The HARNESS initiative

Brain atrophy is increasingly evaluated in cerebral small vessel diseases. We aim at systematically reviewing the available data regarding its extent, correlates and cognitive consequences. Given that in this context, brain atrophy measures might be biased, the first part of the review focuses on technical aspects. Thereafter, data from the literature are analyzed in light of these potential limitations, to better understand the relationships between brain atrophy and other MRI markers of cerebral small vessel diseases. In the last part, we review the links between brain atrophy and cognitive alterations in patients with cerebral small vessel diseases.

MRI phenotypes of the brain are related to future stroke and mortality in patients with manifest arterial disease: The SMART-MR study

Neurodegenerative and neurovascular diseases lead to heterogeneous brain abnormalities. A combined analysis of these abnormalities by phenotypes of the brain might give a more accurate representation of the underlying aetiology. We aimed to identify different MRI phenotypes of the brain and assessed the risk of future stroke and mortality within these subgroups. In 1003 patients (59 ± 10 years) from the Second Manifestations of ARTerial disease-Magnetic Resonance (SMART-MR) study, different quantitative 1.5T brain MRI markers were used in a hierarchical clustering analysis to identify 11 distinct subgroups with a different distribution in brain MRI markers and cardiovascular risk factors, and a different risk of stroke (Cox regression: from no increased risk compared to the reference group with relatively few brain abnormalities to HR = 10.34; 95% CI 3.80↔28.12 for the multi-burden subgroup) and mortality (from no increased risk compared to the reference group to HR = 4.00; 95% CI 2.50↔6.40 for the multi-burden subgroup). In conclusion, within a group of patients with manifest arterial disease, we showed that different MRI phenotypes of the brain can be identified and that these were associated with different risks of future stroke and mortality. These MRI phenotypes can possibly classify individual patients and assess their risk of future stroke and mortality.

Cognitive Function in Dementia-Free Subjects and Survival in Old Age: The PROSPER Study

BACKGROUND

Impairment in domain-specific cognitive function is associated with the increased risk of mortality. We prospectively evaluated the association of executive function and memory with the risk of long-term mortality in dementia-free older subjects. Moreover, we investigated the role of structural brain abnormalities in this association.

METHODS

We included 547 dementia-free participants (mean age 78 years, 56.5% male) from the nested magnetic resonance imaging sub-study of the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER). Cox proportional hazard models were used to model 10-year risk of all-cause, cardiovascular, and noncardiovascular mortality in relation to performance in executive function and memory. Moreover, we evaluated the role of total brain parenchymal volume, cerebral blood flow, white matter hyperintensity, and the presence of microbleeds and infarcts in the link between cognitive function and mortality.

RESULTS

In the multivariable model, lower performance in executive function was associated with greater risk of all-cause (hazard ratio [HR] 1.49; 95% confidence interval [CI], 1.31-1.70), cardiovascular (HR 1.69; 95% CI, 1.36-2.11), and noncardiovascular (HR 1.36; 95% CI, 1.15-1.62) mortality. Similarly, poorer performance in memory tests associated with higher risk of all-cause (HR 1.47; 95% CI, 1.29-1.68), cardiovascular (HR 1.45; 95% CI, 1.15-1.83), and noncardiovascular (HR 1.49; 95% CI, 1.27-1.76) mortality. The associations were similar in subjects with various levels of brain structural abnormalities and cerebral blood flow (all P for interaction ≫ .05).

CONCLUSIONS

Poorer performance in both executive function and memory tests associates with all-cause, cardiovascular, and noncardiovascular mortality in elderly individuals. This association is independent of cardiovascular risk factors and diseases, brain structural abnormalities, and cerebral blood flow.

Clinical Significance of Magnetic Resonance Imaging Markers of Vascular Brain Injury: A Systematic Review and Meta-analysis

Importance

Covert vascular brain injury (VBI) is highly prevalent in community-dwelling older persons, but its clinical and therapeutic implications are debated.

Objective

To better understand the clinical significance of VBI to optimize prevention strategies for the most common age-related neurological diseases, stroke and dementia.

Data Source

We searched for articles in PubMed between 1966 and December 22, 2017, studying the association of 4 magnetic resonance imaging (MRI) markers of covert VBI (white matter hyperintensities [WMHs] of presumed vascular origin, MRI-defined covert brain infarcts [BIs], cerebral microbleeds [CMBs], and perivascular spaces [PVSs]) with incident stroke, dementia, or death.

Study Selection

Data were taken from prospective, longitudinal cohort studies including 50 or more adults.

Data Extraction and Synthesis

We performed inverse variance-weighted meta-analyses with random effects and z score-based meta-analyses for WMH burden. The significance threshold was P < .003 (17 independent tests). We complied with the Meta-analyses of Observational Studies in Epidemiology guidelines.

Main Outcomes and Measures

Stroke (hemorrhagic and ischemic), dementia (all and Alzheimer disease), and death.

Results

Of 2846 articles identified, 94 studies were eligible, with up to 14 529 participants for WMH, 16 012 participants for BI, 15 693 participants for CMB, and 4587 participants for PVS. Extensive WMH burden was associated with higher risk of incident stroke (hazard ratio [HR], 2.45; 95% CI, 1.93-3.12; P < .001), ischemic stroke (HR, 2.39; 95% CI, 1.65-3.47; P < .001), intracerebral hemorrhage (HR, 3.17; 95% CI, 1.54-6.52; P = .002), dementia (HR, 1.84; 95% CI, 1.40-2.43; P < .001), Alzheimer disease (HR, 1.50; 95% CI, 1.22-1.84; P < .001), and death (HR, 2.00; 95% CI, 1.69-2.36; P < .001). Presence of MRI-defined BIs was associated with higher risk of incident stroke (HR, 2.38; 95% CI, 1.87-3.04; P < .001), ischemic stroke (HR, 2.18; 95% CI, 1.67-2.85; P < .001), intracerebral hemorrhage (HR, 3.81; 95% CI, 1.75-8.27; P < .001), and death (HR, 1.64; 95% CI, 1.40-1.91; P < .001). Presence of CMBs was associated with increased risk of stroke (HR, 1.98; 95% CI, 1.55-2.53; P < .001), ischemic stroke (HR, 1.92; 95% CI, 1.40-2.63; P < .001), intracerebral hemorrhage (HR, 3.82; 95% CI, 2.15-6.80; P < .001), and death (HR, 1.53; 95% CI, 1.31-1.80; P < .001). Data on PVS were limited and insufficient to conduct meta-analyses but suggested an association of high PVS burden with increased risk of stroke, dementia, and death; this requires confirmation.

Conclusions and Relevance

We report evidence that MRI markers of VBI have major clinical significance. This research prompts careful evaluation of the benefit-risk ratio for available prevention strategies in individuals with covert VBI.

Cerebral Small Vessel Disease Burden and All-Cause Mortality: Mayo Clinic Florida Familial Cerebrovascular Diseases Registry

GOAL

Cerebral small vessel disease (CSVD) leads to cognitive decline, gait disturbances, mood changes, and an increased risk of stroke. The goal of this study is to describe the relationship between a composite radiographic CSVD score and all-cause mortality.

MATERIALS AND METHODS

Data were collected from a prospective registry of patients with and without cerebrovascular disease from November 2010 through April 2018. The radiographic Total CSVD Score (tSVD) ranges from 0 (minimal disease) to 4 (severe disease), based on detection of lacunar infarcts, cerebral microbleeds, perivascular spaces, and subcortical or periventricular white matter hyperintensities. All-cause mortality served as the primary endpoint. The independent relationship between CSVD burden and all-cause mortality was assessed using Cox regression models with significance being P < .05.

FINDINGS

Four hundred and forty-nine patients were included (mean age, 63 years; 50.1% [225 of 449] women). The hazard ratio for mortality significantly increased with advancing score (1.92, P = .014 score 1; 2.92, P < .001 score 2; 4.23, P < .001 combined scores 3 and 4). Significance remained despite adjustment for coexistent cerebrovascular risk factors aside from age.

CONCLUSIONS

The clinically practical tSVD score may serve as a predictor for all-cause mortality in populations with high disease prevalence. Continued investigations are needed to better understand the effects of risk factor modification on mortality and pathogenesis with the goal of developing disease modifying therapies.

Asymptomatic Cerebral Small Vessel Disease: Insights from Population-Based Studies

Cerebral small vessel disease (CSVD) is a common group of neurological conditions that confer a significant burden of morbidity and mortality worldwide. In most cases, CSVD is only recognized in its advanced stages once its symptomatic sequelae develop. However, its significance in asymptomatic healthy populations remains poorly defined. In population-based studies of presumed healthy elderly individuals, CSVD neuroimaging markers including white matter hyperintensities, lacunes, cerebral microbleeds, enlarged perivascular spaces, cortical superficial siderosis, and cerebral microinfarcts are frequently detected. While the presence of these imaging markers may reflect unique mechanisms at play, there are likely shared pathways underlying CSVD. Herein, we aim to assess the etiology and significance of these individual biomarkers by focusing in asymptomatic populations at an epidemiological level. By primarily examining population-based studies, we explore the risk factors that are involved in the formation and progression of these biomarkers. Through a critical semi-systematic review, we aim to characterize “asymptomatic” CSVD, review screening modalities, and draw associations from observational studies in clinical populations. Lastly, we highlight areas of research (including therapeutic approaches) in which further investigation is needed to better understand asymptomatic CSVD.

Perivascular spaces contribute to cognition beyond other small vessel disease markers

OBJECTIVE

To cross-sectionally relate multiple small vessel disease (SVD) neuroimaging markers to cognition among older adults.

METHODS

Vanderbilt Memory & Aging Project participants free of clinical dementia and stroke (n = 327, age 73 ± 7 years, 59% male, 40% with mild cognitive impairment) completed neuropsychological assessment and 3T MRI to measure white matter hyperintensities (WMH), perivascular spaces (PVS), cerebral microbleeds (CMBs), and lacunes. Linear regressions related each SVD marker to neuropsychological performances and adjusted for age, sex, race/ethnicity, education, cognitive diagnosis, APOE ε4 presence, Framingham Stroke Risk Profile, and intracranial volume.

RESULTS

WMH related to the most neuropsychological measures, including the Boston Naming Test, Animal Naming, Coding, Number Sequencing, Executive Function Composite, and Hooper Visual Organization Test performances (p ≤ 0.01). PVS related to multiple information processing and executive function performances (p ≤ 0.02). Lacunes and CMBs related to fewer measures than expected. Combined models simultaneously testing multiple statistically significant SVD predictors suggested that WMH, PVS, and CMBs each independently related to information processing and executive function performances; however, compared to other SVD markers, PVS remained statistically significant in models related to information processing and executive functioning performances.

CONCLUSIONS

As expected, increased WMH corresponded to poorer performances across multiple cognitive domains. PVS, previously considered a benign neuroimaging feature in older adults, may have important clinical implications because PVS was related to information processing and executive function performances even in combined models. On the basis of models with multiple SVD predictors, WMH, PVS, and CMBs may each reflect a separate pathway of small vessel injury.

The consequence of cerebral small vessel disease: Linking brain atrophy to motor impairment in the elderly

In the elderly, brain structural deficits and gait disturbances due to cerebral small vessel disease (CSVD) have been well demonstrated. The relationships among CSVD, brain atrophy, and motor impairment, however, are far from conclusive. Particularly, the effect of CSVD on subcortical nuclear atrophy, motor performance of upper extremities, and associating patterns between brain atrophy and motor impairment remains largely unknown. To address these gaps, this study recruited 770 community-dwelling subjects (35-82 years of age), including both CSVD and non-CSVD individuals. For each subject, four motor tests involving upper and lower extremities were completed. High-resolution structural MRI was applied to extract gray matter (GM) volume, white matter volume, cortical thickness, surface area, and subcortical nuclear (caudate, putamen, pallidum, and thalamus) volumes. The results showed worse motor performance of lower extremities but relatively preserved performance of upper extremities in the CSVD group. Intriguingly, there was a significant association between the worse performance of upper extremities and atrophy of whole-brain GM and pallidum in the CSVD group but not in the non-CSVD group. In addition, mediation analysis confirmed a functional CSVD-to-"brain atrophy"-to-"motor impairment" pathway, that is, a mediating role of thalamic atrophy in the CSVD effect on walking speed in the elderly, indicating that CSVD impairs walking performance through damaging the integrity of the thalamus in aging populations. These findings provide important insight into the functional consequences of CSVD and highlight the importance of evaluating upper extremities functions and exploring their brain mechanisms in CSVD populations during aging.

Brain age predicts mortality

Age-associated disease and disability are placing a growing burden on society. However, ageing does not affect people uniformly. Hence, markers of the underlying biological ageing process are needed to help identify people at increased risk of age-associated physical and cognitive impairments and ultimately, death. Here, we present such a biomarker, 'brain-predicted age', derived using structural neuroimaging. Brain-predicted age was calculated using machine-learning analysis, trained on neuroimaging data from a large healthy reference sample (N=2001), then tested in the Lothian Birth Cohort 1936 (N=669), to determine relationships with age-associated functional measures and mortality. Having a brain-predicted age indicative of an older-appearing brain was associated with: weaker grip strength, poorer lung function, slower walking speed, lower fluid intelligence, higher allostatic load and increased mortality risk. Furthermore, while combining brain-predicted age with grey matter and cerebrospinal fluid volumes (themselves strong predictors) not did improve mortality risk prediction, the combination of brain-predicted age and DNA-methylation-predicted age did. This indicates that neuroimaging and epigenetics measures of ageing can provide complementary data regarding health outcomes. Our study introduces a clinically-relevant neuroimaging ageing biomarker and demonstrates that combining distinct measurements of biological ageing further helps to determine risk of age-related deterioration and death.

Recent Advances in Leukoaraiosis: White Matter Structural Integrity and Functional Outcomes after Acute Ischemic Stroke

Leukoaraiosis, a radiographic marker of cerebral small vessel disease detected on T2-weighted brain magnetic resonance imaging (MRI) as white matter hyperintensity (WMH), is a key contributor to the risk and severity of acute cerebral ischemia. Prior investigations have emphasized the pathophysiology of WMH development and progression; however, more recently, an association between WMH burden and functional outcomes after stroke has emerged. There is growing evidence that WMH represents macroscopic injury to the white matter and that the extent of WMH burden on MRI influences functional recovery in multiple domains following acute ischemic stroke (AIS). In this review, we discuss the current understanding of WMH pathogenesis and its impact on AIS and functional recovery.

Whole blood gene expression and white matter Hyperintensities

Background

White matter hyperintensities (WMH) are an important biomarker of cumulative vascular brain injury and have been associated with cognitive decline and an increased risk of dementia, stroke, depression, and gait impairments. The pathogenesis of white matter lesions however, remains uncertain. The characterization of gene expression profiles associated with WMH might help uncover molecular mechanisms underlying WMH.

Methods

We performed a transcriptome-wide association study of gene expression profiles with WMH in 3248 participants from the Framingham Heart Study using the Affymetrix Human Exon 1.0 ST Array.

Results

We identified 13 genes that were significantly associated with WMH (FDR < 0.05) after adjusting for age, sex and blood cell components. Many of these genes are involved in inflammation-related pathways.

Conclusion

Thirteen genes were significantly associated with WMH. Our study confirms the hypothesis that inflammation might be an important factor contributing to white matter lesions. Future work is needed to explore if these gene products might serve as potential therapeutic targets.

Electronic supplementary material

The online version of this article (10.1186/s13024-017-0209-5) contains supplementary material, which is available to authorized users.

Subclinical Cerebrovascular Disease Increases the Risk of Incident Stroke and Mortality: The Northern Manhattan Study

BACKGROUND

The effects of white matter hyperintensity volume and subclinical brain infarcts on the risk of incident stroke, its ischemic subtypes, and mortality require further study in diverse samples.

METHODS AND RESULTS

Stroke-free participants in the Northern Manhattan Study underwent magnetic resonance imaging (N=1287; mean age 71±9 years, 60% women, 15% non-Hispanic white, 17% non-Hispanic black, 68% Hispanic) and were followed for a median of 8 years (interquartile range: 6-9 years). Cox models estimated proportional hazards of incident stroke of all types, ischemic stroke (and its subtypes), and mortality and stratified by race/ethnicity. In total 72 participants (6%) had incident strokes and 244 died (19%). In fully adjusted models, those with larger white matter hyperintensity volume had greater risk of all stroke types (hazard ratio [HR]: 1.4; 95% CI, 1.1-1.9), ischemic stroke (HR: 1.3; 95% CI, 1.0-1.8), and cryptogenic stroke (HR: 2.2; 95% CI, 1.1-4.4). White and black but not Hispanic participants had increased stroke risk (P<0.05 for heterogeneity for all and ischemic stroke). Those with subclinical brain infarct had greater risk for all stroke types (HR: 1.9; 95% CI, 1.1-3.3), ischemic stroke (HR: 2.2; 95% CI, 1.3-3.8), lacunar (HR: 4.0; 95% CI, 1.3-12.3), and cryptogenic stroke (HR: 3.6; 95% CI, 1.0-12.7), without significant heterogeneity across race/ethnic groups. Greater white matter hyperintensity volume increased both vascular (HR: 1.3; 95% CI, 1.1-1.7) and nonvascular (HR: 1.2; 95% CI, 1.0-1.5) mortality among Hispanic and white but not black participants (P=0.040 for heterogeneity). Subclinical brain infarct was associated with increased vascular mortality among Hispanic participants only (HR: 2.9; 95% CI, 1.4-5.8).

CONCLUSIONS

In this urban US sample, subclinical cerebrovascular lesions increased the risk of clinical stroke and vascular mortality and varied by race/ethnicity and lesion type.

Prediction of Functional Outcome in Ischemic Stroke Patients: An Observational Study on Egyptian Population

Introduction Determining the prognosis of ischemic stroke is important for neurologists and patients. The aim is to study the predictors of three months clinical outcome in ischemic stroke patients. Materials and methods A total of 397 patients were classified according to three months modified Rankin Scale score (mRS score) into two groups, favorable and unfavorable outcome. Favorable outcome was assumed if the score was zero or one, or unchanged if the score was ≥ 1 before the onset of the most recent event. Results The variables associated with unfavorable outcome were old age (P <0.001), presence of cardiac disease (P <0.001), low ejection fraction (P=0.008), low levels of total cholesterol and low-density lipoproteins (P <0.001), large artery atherosclerosis stroke (P <0.001), early confluent (P=0.005), high National Institute of Health stroke scale (NIHSS) score on admission (P <0.001), mRS score before admission (P <0.001), mRS score on discharge (P <0.001). Lacunar stroke was associated with favorable outcome (P <0.001). The regression analysis showed mRS score on discharge (P <0.001) and the presence of cardiac diseases (P=0.077) as independent predictors of unfavorable outcome. Conclusion High mRS score on discharge and presence of the cardiac disease independently could predict the unfavorable outcome and mRS score on discharge had a high sensitivity and negative predictive value in predicting the unfavorable outcome. Abbreviations MRS: score modified Rankin scale score, NIHSS: National Institutes of Health Stroke Scale, MRI: Magnetic resonance imaging, LDL: Low-density lipoprotein, MRA: Magnetic resonance of arteries.

Structural brain changes and all-cause mortality in the elderly population-the mediating role of inflammation

While MRI brain changes have been related to mortality during ageing, the role of inflammation in this relationship remains poorly understood. Hence, this study aimed to investigate the impact of MRI changes on all-cause mortality and the mediating role of cytokines. All-cause mortality was evaluated in 268 community dwelling elderly (age 65-83 years) in the MEMO study (Memory and Morbidity in Augsburg elderly). MRI markers of brain atrophy and cerebral small vessel disease (SVD), C-reactive protein (CRP) and a panel of cytokines in serum were assessed. Cox proportional hazard models were used to estimate the association of MRI changes with survival over 9 years. Regression models were used to assess the hypothesis that inflammation is mediating the relationship between MRI-brain changes and mortality. In total, 77 (29 %) deaths occurred during a mean follow up of 9 years. After adjusting for confounders, the degree of global cortical atrophy and the level of the cytokines CRP, TNF-α and IL-8 were of higher significance in study participants who had died at follow-up in comparison to survivors. In Cox proportional hazard models, higher degrees of global cortical atrophy (HR 1.56, p = 0.003) and regional atrophy of the temporal lobe (HR 1.38, p = 0.011) were associated with a significantly increased risk of mortality. Mediation analyses revealed a partial mediation by IL-6 and IL-8 of the effects of global cortical atrophy on mortality. Global cortical brain atrophy is a significant indicator of survival in the elderly. Our study supports a possible role for inflammation in the atrophy pathogenesis. If replicated in other samples, IL-6 and IL-8 level assessment may improve risk prognosis for mortality.

The Rotterdam Scan Study: design update 2016 and main findings

Imaging plays an essential role in research on neurological diseases in the elderly. The Rotterdam Scan Study was initiated as part of the ongoing Rotterdam Study with the aim to elucidate the causes of neurological disease by performing imaging of the brain in a prospective population-based setting. Initially, in 1995 and 1999, random subsamples of participants from the Rotterdam Study underwent neuroimaging, whereas from 2005 onwards MRI has been implemented into the core protocol of the Rotterdam Study. In this paper, we discuss the background and rationale of the Rotterdam Scan Study. Moreover, we describe the imaging protocol, image post-processing techniques, and the main findings to date. Finally, we provide recommendations for future research, which will also be topics of investigation in the Rotterdam Scan Study.

The bidirectional association between reduced cerebral blood flow and brain atrophy in the general population

The question remains whether reduced cerebral blood flow (CBF) leads to brain atrophy or vice versa. We studied the longitudinal relation between CBF and brain volume in a community-dwelling population. In the Rotterdam Study, 3011 participants (mean age 59.6 years (s.d. 8.0)) underwent repeat brain magnetic resonance imaging to quantify brain volume and CBF at two time points. Adjusted linear regression models were used to investigate the bidirectional relation between CBF and brain volume. We found that smaller brain volume at baseline was associated with a steeper decrease in CBF in the whole population (standardized change per s.d. increase of total brain volume (TBV)=0.296 (95% confidence interval (CI) 0.200; 0.393)). Only in persons aged ⩾65 years, a lower CBF at baseline was associated with steeper decline of TBV (standardized change per s.d. increase of CBF=0.003 (95% CI -0.004; 0.010) in the whole population and 0.020 (95% CI 0.004; 0.036) in those aged ⩾65 years of age). Our results indicate that brain atrophy causes CBF to decrease over time, rather than vice versa. Only in persons aged >65 years of age did we find lower CBF to also relate to brain atrophy.

The Rotterdam Study: 2016 objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, otolaryngological, locomotor, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in over 1200 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy ). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

Methadone use in a male with the FMRI premutation and FXTAS

The fragile X-associated tremor ataxia syndrome (FXTAS) is caused by the premutation in FMR1 gene. Recent reports of environmental toxins appear to worsen the progression of FXTAS. Here we present a case of male adult with FXTAS and a long history of methadone use. The patient shows a faster progression in both symptoms of disease and MRI changes compared to what is typically seen in FXTAS. There has been no research regarding the role of narcotics in onset, progression, and severity of FXTAS symptoms. However, research has shown that narcotics can have a negative impact on several neurodegenerative diseases, and we hypothesize that in this particular case, methadone may have contributed to a faster progression of FXTAS as well as exacerbating white matter disease through RNA toxicity seen in premutation carriers.

Early cerebral small vessel disease and brain volume, cognition, and gait

Objective

Decline in cognitive function begins by the 40s, and may be related to future dementia risk. We used data from a community-representative study to determine whether there are age-related differences in simple cognitive and gait tests by the 40s, and whether these differences were associated with covert cerebrovascular disease on magnetic resonance imaging (MRI).

Methods

Between 2010 and 2012, 803 participants aged 40 to 75 years in the Prospective Urban Rural Epidemiological (PURE) study, recruited from prespecified postal code regions centered on 4 Canadian cities, underwent brain MRI and simple tests of cognition and gait as part of a substudy (PURE-MIND).

Results

Mean age was 58 ± 8 years. Linear decreases in performance on the Montreal Cognitive Assessment, Digit Symbol Substitution Test (DSST), and Timed Up and Go test of gait were seen with each age decade from the 40s to the 70s. Silent brain infarcts were observed in 3% of 40- to 49-year-olds, with increasing prevalence up to 18.9% in 70-year-olds. Silent brain infarcts were associated with slower timed gait and lower volume of supratentorial white matter. Higher volume of supratentorial MRI white matter hyperintensity was associated with slower timed gait and worse performance on DSST, and lower volumes of the supratentorial cortex and white matter, and cerebellum.

Interpretation

Covert cerebrovascular disease and its consequences on cognitive and gait performance and brain atrophy are manifest in some clinically asymptomatic persons as early as the 5th decade of life. Ann Neurol 2015;77:251–261

Brain Volume as an Integrated Marker for the Risk of Death in a Community-Based Sample: Age Gene/Environment Susceptibility--Reykjavik Study

BACKGROUND

Total brain volume is an integrated measure of health and may be an independent indicator of mortality risk independent of any one clinical or subclinical disease state. We investigate the association of brain volume to total and cause-specific mortality in a large nondemented stroke-free community-based cohort.

METHODS

The analysis includes 3,543 men and women (born 1907-1935) participating in the Age, Gene, Environment Susceptibility-Reykjavik Study. Participants with a known brain-related high risk for mortality (cognitive impairment or stroke) were excluded from these analyses. Quantitative estimates of total brain volume, white matter, white matter lesions, total gray matter (GM; cortical GM and subcortical GM separately), and focal cerebral vascular disease were generated from brain magnetic resonance imaging. Brain atrophy was expressed as brain tissue volume divided by total intracranial volume, yielding a percentage. Mean follow-up duration was 7.2 (0-10) years, with 647 deaths. Cox regression was used to analyze the association of mortality to brain atrophy, adjusting for demographics, cardiovascular risk factors, and cerebral vascular disease.

RESULTS

Reduced risk of mortality was significantly associated with higher total brain volume (hazard ratio, 95% confidence interval = 0.71, 0.65-0.78), white matter (0.85, 0.78-0.93), total GM (0.74, 0.68-0.81), and cortical GM (0.78, 0.70-0.87). Overall, the associations were similar for cardiovascular and noncardiovascular-related deaths.

CONCLUSIONS

Independent of multiple risk factors and cerebral vascular damage, global brain volume predicts mortality in a large nondemented stroke-free community-dwelling older cohort. Total brain volume may be an integrated measure reflecting a range of health and with further investigation could be a useful clinical tool when assessing risk for mortality.

Brain volumes and risk of cardiovascular events and mortality. The SMART-MR study

Brain atrophy is a strong predictor for cognitive decline and dementia, and these are, in turn, associated with increased mortality in the general population. Patients with cardiovascular disease have more brain atrophy and a higher morbidity and mortality. We investigated if brain volumes on magnetic resonance imaging were associated with the risk of cardiovascular events and mortality in patients with manifest arterial disease (n = 1215; mean age 58 years). Automated brain segmentation was used to quantify intracranial volume, and volumes of total brain, sulcal cerebrospinal fluid, and ventricles. After a median follow-up of 8.3 years, 184 patients died, 49 patients had an ischemic stroke, and 100 patients had an ischemic cardiac complication. Smaller relative brain volumes increased the risk of all-cause death (hazard ratio [HR] per standard deviation decrease in total brain volume: 1.58, 95% confidence interval [95% CI]: 1.33-1.88), vascular death (HR 1.69, 95% CI: 1.35-2.13), and ischemic stroke (HR 1.96, 95% CI: 1.43-2.69), independent of cardiovascular risk factors. These results suggest that brain volumes are an important determinant of poor outcome in patients with high cardiovascular risk.

White matter disease as a biomarker for long-term cerebrovascular disease and dementia

OPINION STATEMENT

White matter disease is commonly detected on brain MRI of aging individuals as white matter hyperintensities (WMH), or 'leukoaraiosis." Over the years, it has become increasingly clear that the presence and extent of WMH is a radiographic marker of small cerebral vessel disease and an important predictor of the lifelong risk of stroke, cognitive impairment, and functional disability. A number of large population-based studies have outlined the significance of WMH as a biomarker for long-term cerebrovascular disease and dementia. In this review, we describe the conceptual framework and methodology that support this association and link the existing knowledge to future lines of investigation in the field.

Do cardiovascular risk factors explain the link between white matter hyperintensities and brain volumes in old age? A population-based study

BACKGROUND AND PURPOSE

White matter hyperintensities (WMHs) and brain atrophy frequently coexist in older people. However, it is unclear whether the association between these two brain lesions is dependent on the aging process, a vascular mechanism or genetic susceptibility. It was therefore investigated whether the association between load of WMHs and brain atrophy measures is related to age, vascular risk factors (VRFs) or the APOE-ε4 allele.

METHODS

This population-based study included 492 participants (age ≥60 years, 59.6% women) free of dementia and stroke. Data on demographics, VRFs and APOE genotypes were collected through interviews, clinical examination and laboratory tests. WMHs on magnetic resonance images were assessed using manual visual rating and automatic volumetric segmentation. Hippocampal and ventricular volumes were manually delineated, whereas total gray matter (GM) volume was measured by automatic segmentation. Data were analyzed with multivariate linear regression models.

RESULTS

More global WMHs, assessed using either a visual rating scale or a volumetric approach, were significantly associated with lower GM volume and higher ventricular volume; the associations remained significant after adjusting for age, VRFs and the APOE-ε4 allele. In contrast, the association between global WMHs and hippocampal volume was no longer significant after adjusting for age, whereas adjustment for VRFs and APOE-ε4 had no influential effect.

CONCLUSION

The association of global WMHs with lower GM volume and higher ventricular volume is independent of age, VRFs and APOE-ε4 allele, suggesting that the process of cerebral microvascular disease and neurodegeneration are associated independently of the normal aging process, vascular mechanisms or genetic susceptibility.

The Rotterdam Study: 2014 objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, oncological, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in over a 1,000 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy ). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

Association of walking speed in late midlife with mortality: results from the Whitehall II cohort study

Slow walking speed is associated with increased mortality in the elderly, but it is unknown whether a similar association is present in late midlife. Our aim was to examine walking speed in late midlife as a predictor of mortality, as well as factors that may explain this association. Data are drawn from the Whitehall II longitudinal cohort study of British civil servants. The analyses are based on 6,266 participants (29% women; mean age = 61 years, SD = 6) for whom "walking speed at usual pace" was measured over 8 ft (2.44 m) at baseline. Participants were followed for all-cause and cause-specific mortalities during a mean of 6.4 (SD = 0.8) years. During this period, 227 participants died. Participants in the bottom sex-specific third of walking speed (men, <1.26 m/s; women, <1.09 m/s) had an increased risk of death compared to those in the middle and top thirds (age- and sex-adjusted hazard ratio = 1.89, 95% confidence interval (CI) = 1.45-2.46), with no evidence of effect modification by age or sex (interactions, P ≥ 0.40). The association between walking speed and mortality was partially explained by baseline inflammatory markers (percentage reduction of the association 22.8%), height and body mass index (16.6%), chronic diseases (14.0%), and health behaviors (13.4%). Together these and other baseline factors (socioeconomic status, cardiovascular risk factors, cognitive function) explained 48.5% of the association (adjusted hazard ratio = 1.39, 95% CI = 1.04-1.84). In conclusion, walking speed measured in late midlife seems to be an important marker of mortality risk; multiple factors, in particular inflammatory markers, partially explain this association.

Lower susceptibility to cerebral small vessel disease in human familial longevity: the Leiden Longevity Study

BACKGROUND AND PURPOSE

On MRI, cerebral white matter lesions, lacunar infarcts, and cerebral microbleeds are common imaging correlates of cerebral small vessel damage in apparently healthy elderly individuals. We investigated whether middle-aged to elderly offspring of nonagenarian siblings, who are predisposed to become long-lived as well, have a lower prevalence of white matter lesions, lacunar infarcts, and cerebral microbleeds than control subjects.

METHODS

All subjects were from the Leiden Longevity Study. In this study, middle-aged to elderly offspring of nonagenarian siblings, who are predisposed to become long-lived as well, were contrasted to their spouses. Cerebral small vessel disease was assessed using 3-T MRI.

RESULTS

Offspring were less likely to have severe periventricular frontal caps (odds ratio [OR], 0.3; 95% confidence interval [CI], 0.1-1.1; P trend=0.01) and severe periventricular bands (OR, 0.4; 95% CI, 0.2-0.8; P trend=0.02). Moreover, offspring were less likely to have frontal (OR, 0.4; 95% CI, 0.2-0.9; P trend=0.05), parietal (OR, 0.4; 95% CI, 0.1-0.9; P trend=0.001), temporal (OR, 0.3; 95% CI, 0.1-0.8]; P trend=0.004), and occipital subcortical white matter lesions (OR, 0.3; 95% CI, 0.1-0.6; P trend=0.001). Prevalence of lacunar infarcts also was lower in offspring (OR, 0.3; 95% CI, 0.1-1.1; P=0.07). Prevalence of microbleeds was not significantly different in offspring and control subjects.

CONCLUSIONS

Exceptional familial longevity is associated with a lower susceptibility to white matter lesions and lacunar infarcts, but not cerebral microbleeds.

Age- and sex-specific rates of leukoaraiosis in TIA and stroke patients: population-based study

OBJECTIVE

To determine any sex differences in age-specific prevalence or severity of leukoaraiosis, a marker of white matter ischemia, in population-based and clinic cohorts of TIA/stroke and in a systematic review of the literature.

METHODS

Age-specific sex differences were calculated for both CT and MRI in the Oxford Vascular Study (OXVASC) and in an MRI-based clinic cohort. We pooled odds ratios (ORs) for leukoaraiosis in women vs men from published studies by fixed-effect meta-analysis, stratified by patient characteristics (stroke vs nonstroke) and CT vs MRI.

RESULTS

Among 10 stroke studies (all CT-based), leukoaraiosis was most frequent in women (OR = 1.42, 95% confidence interval [CI] 1.27-1.57, p < 0.0001), with little heterogeneity between studies (p = 0.28). However, no such excess was seen in 10 reports of nonstroke cohorts (0.91, 0.67-1.24, p = 0.56). Moreover, excess leukoaraiosis in women on CT-imaging in OXVASC (1.38, 1.15-1.67, p = 0.001) was explained by their older age (age-adjusted OR = 1.01, 0.82-1.25, p = 0.90). Leukoaraiosis was more severe in older (≥ 75) women (CT-1.50, 1.14-1.97, p = 0.004 in OXVASC; MRI-1.70, 1.17-2.48, p = 0.006 in OXVASC and clinic cohort). However, leukoaraiosis was independently associated with early mortality (hazard ratio = 1.46, 1.23-1.73, p < 0.0001), suggesting that comparisons in older age groups will be biased by prior premature death of men with leukoaraiosis. Sex differences in severity of leukoaraiosis were not addressed in previous studies.

CONCLUSIONS

Previously reported excess leukoaraiosis in women with TIA/stroke is likely to be confounded by age and apparently greater severity in older women is likely to be biased by premature death in men with leukoaraiosis.

Mood problems increase the risk of mortality in patients with lacunar infarcts: the SMART-MR study

OBJECTIVE

A relationship between depression and mortality has been well established, but underlying mechanisms remain unclear. We investigated the influence of cerebral small vessel disease (CSVD), characterized by white matter lesions (WMLs) and lacunar infarcts, on the relationship between mood mortality during 6 years follow-up.

METHODS

Mood problems were assessed with the mental component summary of the 36-item Short-Form Medical Outcomes Study in 1110 patients with symptomatic atherosclerotic disease (mean age 59 years). Volumetric WML estimates were obtained with 1.5-T magnetic resonance imaging; lacunar infarcts were scored visually. Cox regression models were adjusted for age, sex, vascular risk, physical functioning, antidepressants and infarcts. We adjusted for CSVD to examine whether it may be an intermediate or confounding factor. Second, we added interaction terms to investigate whether associations differed between patients with CSVD (absent/present).

RESULTS

Patients in the lowest quartile of mental functioning, representing most severe mood problems, were at higher, although not significant, risk of death (hazard ratio [HR] = 1.47, 95% confidence interval [CI] = 0.94-2.30) compared with patients in higher quartiles. Adjustment for CSVD did not change this association. Lacunar infarcts, not WML, modified the association of mood problems with mortality (p value for interaction = .01); mood problems strongly increased the risk of mortality in patients with lacunar infarcts (HR = 2.75, 95% CI = 1.41-5.38) but not in those without it (HR = 0.78, 95% CI = 0.39-1.57).

CONCLUSIONS

Patients with lacunar infarcts may be especially vulnerable for the effect of mood problems on mortality.

Brain aging, cognition in youth and old age and vascular disease in the Lothian Birth Cohort 1936: rationale, design and methodology of the imaging protocol

RATIONALE

As the population of the world ages, age-related cognitive decline is becoming an ever-increasing problem. However, the changes in brain structure that accompany normal aging, and the role they play in cognitive decline, remain to be fully elucidated.

AIMS

This study aims to characterize changes in brain structure in old age, and to investigate relationships between brain aging and cognitive decline using the Lothian Birth Cohort 1936. Here, we report the rationale, design and methodology of the brain and neurovascular imaging protocol developed to study this cohort.

DESIGN

An observational, longitudinal study of the Lothian Birth Cohort 1936, which comprises 1091 relatively healthy individuals now in their 70s and living in the Edinburgh area. They are surviving participants of the Scottish Mental Survey 1947, which involved a test of general intelligence taken at age 11 years. At age 70 years, the Lothian Birth Cohort 1936 undertook detailed cognitive, medical and genetic testing, and provided social, family, nutritional, quality of life and physical activity information. At mean age 73 years they underwent detailed brain MRI and neurovascular ultrasound imaging, repeat cognitive and other testing. The MRI protocol is designed to provide qualitative and quantitative measures of gray and white matter atrophy, severity and location of white matter lesions, enlarged perivascular spaces, brain mineral deposits, microbleeds and integrity of major white matter tracts. The neurovascular ultrasound imaging provides velocity, stenosis and intima-media thickness measurements of the carotid and vertebral arteries.

STUDY

This valuable imaging dataset will be used to determine which changes in brain structural parameters have the largest effects on cognitive aging. Analysis will include multimodal image analysis and multivariate techniques, such as factor analysis and structural equation modelling. Especially valuable is the ability within this sample to examine the influence that early life intelligence has on brain structural parameters in old age, and the role of genetic, vascular, educational and lifestyle factors.

OUTCOMES

Final outcomes include associations between early and late life cognition and integrity of key white matter tracts, volume of gray and white matter, myelination, brain water content, and visible abnormalities such as white matter lesions and mineral deposits; and influences of vascular risk factors, diet, environment, social metrics, education and genetics on healthy brain aging. It is intended that this information will help to inform and develop strategies for successful cognitive aging.

Neuroimaging predictors of death and dementia in a cohort of older stroke survivors

BACKGROUND

Stroke is a risk factor for subsequent death and dementia. Being able to identify subjects at particular risk would be beneficial to inform treatment and patient management.

METHODS SUBJECTS

aged over 75 years with incident stroke were recruited. Subjects had a cognitive assessment at 3 months post stroke to exclude dementia, and had an MRI scan (n=106) at that time. Subjects were then followed longitudinally for incident dementia and/or death.

RESULTS

Independent neuroimaging predictors of survival to dementia were medial temporal atrophy (MTA; p=0.013) and the presence of thalamic infarcts (p=0.002). After inclusion of cognitive score in the model, the significance of MTA (p=0.049) and thalamic infarcts (p=0.04) was reduced, with survival being best predicted by baseline cognitive score (p=0.004). The only independent significant predictor of survival to death was MTA. Apart from thalamic infarcts, the NINDS/AIREN neuroimaging criteria did not independently predict survival to death or dementia.

CONCLUSIONS

MTA was associated with shorter time to dementia, suggesting a role for Alzheimer pathology in the development of post stroke dementia.

Medial temporal lobe is vulnerable to vascular risk factors in men: a population-based study

BACKGROUND AND PURPOSE

Vascular risk factors (VRFs) are known to cause cerebral microvascular disease, but evidence supporting an effect of VRFs on regional brain atrophy is mixed. We investigate whether an aggregation of VRFs is associated with volume of hippocampus and entorhinal cortex in elderly people living in the community.

METHODS

This cross-sectional study consists of 523 participants (age ≥60 years, 59.3% women) of the SNAC-K Study in central Stockholm, Sweden, who were free of clinical stroke and cognitive impairment. We collected data on VRFs through interviews, clinical examination and inpatient register system. Hippocampal and entorhinal cortex volume was manually measured on magnetic resonance images. Data were analysed with general linear regression models controlling for demographics and total intracranial volume.

RESULTS

  In men, high total cholesterol and diabetes were significantly or marginally associated with smaller hippocampus and entorhinal cortex; when current smoking, binge alcohol drinking, high cholesterol and diabetes were aggregated, an increasing number of VRFs were significantly associated with decreasing volume of hippocampus and entorhinal cortex (P for linear trend <0.01). In women, none of individual VRFs or their aggregation was significantly associated with the volume of these brain regions, except former smoking that was significantly associated with a larger volume of these regions.

CONCLUSIONS

Aggregation of VRFs is associated with reduced hippocampal and entorhinal cortex volume in apparently healthy elderly men, but not in women. This implies that in men, the medial temporal lobe is vulnerable to cardiovascular risk factors.