Silent brain infarcts : frequency, risk factors, and prognosis

Silent- i.e. asymptomatic -brain infarcts are frequently seen on cerebral magnetic resonance imaging (MRl) scans in patients admitted to the hospital with their first stroke. With the increasing use and improvement of imaging techniques, these silent lesions are more often found in people without stroke-like symptoms.' In contrast to symptomatic brain infarcts, the relevance of these so-called silent brain infarcts is not known. Because knowledge of the consequences of silent infarcts is lacking, special treatment regimens have not been developed yet for patients with these lesions. In selected patient groups however, silent brain infarcts seem to increase the risk of stroke and death? Furthermore, hospital-based studies found that they are more frequently present in elderly patients with dementia and depression than in other patients.3 • 4 Prospective longitudinal research in which large groups of asymptomatic people undergo brain imaging is needed to examine the clinical relevance of silent brain infarcts in the general population. In this thesis the following questions are investigated: 1. How frequent are silent brain infarcts in the general population? 2. What are the risk factors for silent brain infarcts? 3. What are the clinical consequences of silent brain infarcts? To answer these questions, data was used from the Rotterdam Scan Study, a large cohort study among elderly people from the general population who underwent MRl scanning of the brain. The presence of (silent) brain infarcts was scored on MRI, as were other brain abnormalities including white matter lesions and global brain atrophy. Both are thought to have a vascular pathogenesis and frequently coexist in ischaemic brains.5·6 In chapter 2, the prevalence and incidence of silent brain infarcts is presented. Furthermore, this chapter describes studies on the risk factors for silent brain infarcts, in which a comparison with the classical risk factors for symptomatic infarcts is made. The investigation of the relationship with one of the relative new risk factors, the potentially modifiable homocysteine, is also reported here. For studies described in chapter 3, this cohort is followed over time and monitored for mortality and major morbidity. This chapter describes the relationship between silent brain infarcts and the risk of three frequent and disabling disorders in elderly people, namely stroke, dementia, and depression. In chapter 4, I discuss and review all findings and make suggestions for further researc

Silent brain infarcts and the risk of dementia and cognitive decline

BACKGROUND: Silent brain infarcts are frequently seen on magnetic resonance imaging (MRI) in healthy elderly people and may be associated with dementia and cognitive decline. METHODS: We studied the association between silent brain infarcts and the risk of dementia and cognitive decline in 1015 participants of the prospective, population-based Rotterdam Scan Study, who were 60 to 90 years of age and free of dementia and stroke at base line. Participants underwent neuropsychological testing and cerebral MRI at base line in 1995 to 1996 and again in 1999 to 2000 and were monitored for dementia throughout the study period. We performed Cox proportional-hazards and multiple linear-regression analyses, adjusted for age, sex, and level of education and for the presence or absence of subcortical atrophy and white-matter lesions. RESULTS: During 3697 person-years of follow-up (mean per person, 3.6 years), dementia developed in 30 of the 1015 participants. The presence of silent brain infarcts at base line more than doubled the risk of dementia (hazard ratio, 2.26; 95 percent confidence interval, 1.09 to 4.70). The presence of silent brain infarcts on the base-line MRI was associated with worse performance on neuropsychological tests and a steeper decline in global cognitive function. Silent thalamic infarcts were associated with a decline in memory performance, and nonthalamic infarcts with a decline in psychomotor speed. When participants with silent brain infarcts at base line were subdivided into those with and those without additional infarcts at follow-up, the decline in cognitive function was restricted to those with additional silent infarcts. CONCLUSIONS: Elderly people with silent brain infarcts have an increased risk of dementia and a steeper decline in cognitive function than those without such lesions

The role of menaquinones (vitamin K2) in human health

Recent reports have attributed the potential health benefits of vitamin K beyond its function to activate hepatic coagulation factors. Moreover, several studies have suggested that menaquinones, also known as vitamin K2, may be more effective in activating extra-hepatic vitamin K-dependent proteins than phylloquinone, also known as vitamin K1. Nevertheless, present dietary reference values (DRV) for vitamin K are exclusively based on phylloquinone, and its function in coagulation. The present review describes the current knowledge on menaquinones based on the following criteria for setting DRV: optimal dietary intake; nutrient amount required to prevent deficiency, maintain optimal body stores and/or prevent chronic disease; factors influencing requirements such as absorption, metabolism, age and sex. Dietary intake of menaquinones accounts for up to 25% of total vitamin K intake and contributes to the biological functions of vitamin K. However, menaquinones are different from phylloquinone with respect to their chemical structure and pharmacokinetics, which affects bioavailability, metabolism and perhaps impact on health outcomes. There are significant gaps in the current knowledge on menaquinones based on the criteria for setting DRV. Therefore, we conclude that further investigations are needed to establish how differences among the vitamin K forms may influence tissue specificities and their role in human health. However, there is merit for considering both menaquinones and phylloquinone when developing future recommendations for vitamin K intak

Homocysteine and brain atrophy on MRI of non-demented elderly

Patients with Alzheimer's disease have higher plasma homocysteine levels than controls, but it is uncertain whether higher plasma homocysteine levels are involved in the early pathogenesis of the disease. Hippocampal, amygdalar and global brain atrophy on brain MRI have been proposed as early markers of Alzheimer's disease. In the Rotterdam Scan Study, a population-based study of age-related brain changes in 1077 non-demented people aged 60-90 years, we investigated the association between plasma homocysteine levels and severity of hippocampal, amygdalar and global brain atrophy on MRI. We used axial T(1)-weighted MRIs to visualize global cortical brain atrophy (measured semi-quantitatively; range 0-15) and a 3D HASTE (half-Fourier acquisition single-shot turbo spin echo) sequence in 511 participants to measure hippocampal and amygdalar volumes. We had non-fasting plasma homocysteine levels in 1031 of the participants and in 505 of the participants with hippocampal and amygdalar volumes. Individuals with higher plasma homocysteine levels had, on average, more cortical atrophy [0.23 units (95% CI 0.07-0.38 units) per standard deviation increase in plasma homocysteine levels] and more hippocampal atrophy [difference in left hippocampal volume -0.05 ml (95% CI -0.09 to -0.01) and in right hippocampal volume -0.03 ml (95% CI -0.07 to 0.01) per standard deviation increase in plasma homocysteine levels]. No association was observed between plasma homocysteine levels and amygdalar atrophy. These results support the hypothesis that higher plasma homocysteine levels are associated with more atrophy of the hippocampus and cortical regions in elderly at risk of Alzheimer's disease

Discordance between the predictors of clinical and imaging remission in patients with early rheumatoid arthritis in clinical practice: implications for the use of ultrasound within a treatment to target strategy

Objective: To assess the prevalence, relationship between and predictors of clinical and imaging remission in early rheumatoid arthritis (RA), achieved with treat-to-target management in clinical practice. Methods: A prospective observational study was conducted in patients with new-onset RA. The treatment target was remission by disease activity score (DAS28-CRP<2.6). Twelve month outcomes included DAS28-CRP remission, DAS44-CRP remission, ACR/EULAR Boolean remission (BR) and absent or absent/minimal power Doppler activity (PDA) on ultrasound (US) of 26 joints (total PDA score=0 or ≤1, respectively). Logistic regression was conducted to identify baseline predictors of these outcomes. Results: Of 105 patients with complete 12-month data, the rate of DAS28-CRP remission was 43%, DAS44-CRP remission was 39%, BR was 14%, absent PDA was 40% and absent/minimal PDA was 57%. Amongst patients achieving clinical remission defined by DAS28-CRP, DAS44-CRP or BR, absence of PDA was observed in 42%, 44% and 40%, respectively; absent/minimal PDA was detected in 62%, 66% and 67%, respectively. On multivariable analysis, shorter symptom duration, male gender, fewer tender joints and lower disability were associated with the clinical remission definitions. Lack of osteoarthritis predicted absence of PDA and lower total baseline PDA predicted absent/minimal PDA. Conclusion: DAS28-CRP remission and absence of PDA were observed in almost half of patients, but less than a quarter achieved both. Achievement of BR was rare. The low agreement between any of the clinical and imaging outcomes and differences in their predictors highlight the complex interaction between symptoms and synovitis, with implications for treat-to-target management. Long-term follow-up should determine the most appropriate target

Vitamin K Status and Lower Extremity Function in Older Adults: The Health Aging and Body Composition Study

While low vitamin K status has been associated with several chronic diseases that can lead to lower extremity disability, it is not known if low vitamin K status is associated with worse lower extremity function