Haemoglobin, magnetic resonance imaging markers and cognition: a subsample of population-based study.

BACKGROUND: Low haemoglobin is highly prevalent among the elderly and has been associated with dementia. However, the mechanisms underlying this association with cognitive dysfunction, either through cerebrovascular disease or neurodegeneration, remain poorly understood. We aimed to examine the association of decreased haemoglobin levels with markers of cerebral small vessel disease (CSVD), neurodegeneration and cognitive impairment in an elderly Asian population. METHODS: A total of 796 Chinese, Malay and Indian participants aged 60 years and older from the Epidemiology of Dementia in Singapore study were included in this study. After providing information on demographics, anthropometry and cardiovascular risk factors, participants underwent 3-T brain magnetic resonance imaging (MRI) to measure markers of CSVD, including cerebral microbleeds, cortical cerebral microinfarcts, lacunes, enlarged perivascular spaces and white matter hyperintensities, as well as neurodegenerative markers, including cortical thickness and subcortical structure volumes quantified using FreeSurfer. Cognition was assessed using a detailed neuropsychological assessment. Logistic and linear regression models were constructed, adjusting for age, gender, education, race, body mass index, smoking, hypertension, hyperlipidaemia, diabetes, glomerular filtration rate and other MRI markers, to test the association between haemoglobin levels and the MRI markers and cognition. RESULTS: Decreased haemoglobin levels were associated with cerebral microbleeds, specifically lobar microbleeds (OR, 1.21; 95% CI, 1.04-1.40; p = 0.015). Decreased haemoglobin levels were also associated with occipital cortical thinning (mean difference, - 0.011; 95% CI, - 0.019, - 0.004; p = 0.003) and smaller accumbens volume (mean difference, - 0.01; 95% CI, - 0.02, 0.00; p = 0.005). A significant association was also observed between decreased haemoglobin levels and poorer global cognitive performance (mean difference, - 0.04; 95% CI, - 0.09, 0.00; p = 0.048). In cognitive domain analysis, associations were again observed between decreased haemoglobin levels and worse performance on attention (mean difference, - 0.05; 95% CI, - 0.10, - 0.01; p = 0.028) and language (mean difference, - 0.06; 95% CI, - 0.12, 0.00; p = 0.048) domains; however, these associations did not survive multiple comparison. CONCLUSIONS: Decreased haemoglobin levels were associated with lobar microbleeds, neurodegenerative markers and cognitive dysfunction. Future studies should ascertain whether iron, folate or vitamin B12 supplementation is able to ameliorate the onset and progression of cognitive impairment and dementia associated with low haemoglobin.

Low levels of plasma omega 3-polyunsaturated fatty acids are associated with cerebral small vessel diseases in acute ischemic stroke patients.

Cerebral small vessel diseases (SVDs) are related to stroke or cognitive dysfunction. n-3-polyunsaturated fatty acids (PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) represent possible disease-modifying factors for cardiovascular disease or dementia. Our hypothesis was that a low proportion of plasma FAs would be associated with cerebral SVDs. We prospectively enrolled 220 patients with a first-episode cerebral infarction within 7 days after symptom onset. The composition of plasma FAs was analyzed by gas chromatography methods. The presence and burden of cerebral microbleeds (CMBs), high-grade white matter changes (HWCs), high-grade perivascular spaces (HPVSs), and asymptomatic lacunar infarctions (ALIs) were investigated. The mean proportion (± SD) was 2.0 ± 0.7 for EPA, 8.9 ± 1.5 for DHA, and 12.0 ± 2.1 for ∑ n-3-PUFAs. In total, 46 (20.9%) patients had CMBs, 64 (29.1 %) had HWCs, 57 (25.9%) had HPVSs, and 65 (29.5%) had ALIs. In univariate analyses, CMBs, HWCs, and HPVSs were each negatively correlated with the proportion of EPA, DHA, and ∑ n-3-PUFAs. In the multivariate analysis, a lower proportion of EPA, DHA and ∑ n-3-PUFAs was associated with the presence of CMBs, HWCs and HPVS, but not ALIs. Total SVDs score was inversely correlated with the proportion of EPA, DHA and ∑ n-3-PUFAs. Overall, we found an association between low proportions of plasma n-3-PUFAs and cerebral SVDs pathologies. Further studies are needed to explore the association and potential therapeutic role of FAs in cerebral SVDs.