Cognitive function in very old men does not correlate to biomarkers of Alzheimer's disease

Background

The Alzheimer’s disease (AD) brain displays atrophy with amyloid-β (Aβ) and tau deposition, whereas decreased Aβ42 and increased tau are measured in cerebrospinal fluid (CSF). The aim of this study was to relate cognitive performance to the degree of brain atrophy, CSF biomarker levels and neuropathology in a cohort of aged men.

Methods

Fifty-eight 86–92-year-old men from the Uppsala Longitudinal Study of Adult Men (ULSAM) cohort underwent cognitive testing, brain computed tomography and lumbar puncture. Atrophy was graded with established scales. Concentrations of CSF Aβ42, t-tau and p-tau were measured by ELISA. Thirteen brains were examined post mortem.

Results

Forty-six of the individuals were considered non-demented, whereas twelve were diagnosed with dementia, either at baseline (n = 4) or during follow-up (n = 8). When comparing subjects with and without dementia, there were no differences in the degree of atrophy, although the mini mental state examination (MMSE) scoring correlated weakly with the degree of medial temporal atrophy (MTA) (p = 0.04). Moreover, the CSF biomarker levels did not differ significantly between healthy (n = 27) and demented (n = 8) subjects (median values 715 vs 472 pg/ml for Aβ42, 414 vs 427 pg/ml for t-tau and 63 vs 60 pg/ml for p-tau). Similarly, there were no differences in the biomarker levels between individuals with mild (n = 24) and severe (n = 11) MTA (median values 643 vs 715 pg/ml for Aβ42, 441 vs 401 pg/ml for t-tau and 64 vs 53 pg/ml for p-tau). Finally, the neuropathological changes did not correlate with any of the other measures.

Conclusion

In this cohort of aged men only a weak correlation could be seen between cognitive performance and MTA, whereas the various neuroradiological, biochemical and neuropathological measures did not correlate with each other. Thus, AD biomarkers seem to be less informative in subjects of an advanced age.

High tau levels in cerebrospinal fluid predict rapid decline and increased dementia mortality in Alzheimer's disease

OBJECTIVE

Cerebrospinal fluid (CSF) amyloid β42 (Aβ42), total tau (t-tau) and phosphorylated tau (p-tau) are useful as predictors of conversion from mild cognitive impairment (MCI) to Alzheimer's disease (AD) dementia. However, results are contradictory as to whether these biomarkers reflect the future rate of clinical decline.

METHODS

This is a retrospective study on 196 patients with AD [mild/moderate AD (n = 72) or AD-MCI (n = 124) at baseline] with a follow-up period of 2-9 years' duration (median 6 years). Lumbar punctures were performed at baseline as a part of the diagnostic procedure.

RESULTS

We found an increased risk of rapid cognitive decline defined as a drop in the Mini-Mental State Examination score of ≥ 4 points/year in patients with CSF t-tau concentrations above the median (OR 3.31, 95% CI 1.53-7.16) and CSF p-tau above the median (OR 2.53, 95% CI 1.21-5.26). Patients with CSF t-tau in the highest quartile had a higher risk of dying in severe dementia (HR 4.67, 95% CI 1.16-18.82).

CONCLUSIONS

In this large AD cohort, we found an association between high levels of CSF t-tau and p-tau and a more aggressive course of the disease, measured as a rapid cognitive decline and a higher risk of dying in severe dementia.

Re-evaluation of clinical dementia diagnoses with pittsburgh compound B positron emission tomography

Objectives

There is an overlap regarding Pittsburgh compound B (PIB) retention in patients clinically diagnosed as Alzheimer's disease (AD) and non-AD dementia. The aim of the present study was to investigate whether there are any differences between PIB-positive and PIB-negative patients in a mixed cohort of patients with neurodegenerative dementia of mild severity regarding neuropsychological test performance and regional cerebral glucose metabolism measured with [¹⁸F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET).

Methods

Eighteen patients clinically diagnosed as probable AD or frontotemporal dementia were examined with PIB PET, FDG PET and neuropsychological tests and followed for 5-9 years in a clinical setting.

Results

The PIB-positive patients (7 out of 18) had slower psychomotor speed and more impaired visual episodic memory than the PIB-negative patients; otherwise performance did not differ between the groups. The initial clinical diagnoses were changed in one third of the patients (6 out of 18) during follow-up.

Conclusions

The subtle differences in neuropsychological performance, the overlap of hypometabolic patterns and clinical features between AD and non-AD dementia highlight the need for amyloid biomarkers and a readiness to re-evaluate the initial diagnosis.

Late-life obesity is associated with smaller global and regional gray matter volumes: a voxel-based morphometric study

OBJECTIVE:

Obesity adversely affects frontal lobe brain structure and function. Here we sought to show that people who are obese versus those who are of normal weight over a 5-year period have differential global and regional brain volumes.

DESIGN:

Using voxel-based morphometry, contrasts were done between those who were recorded as being either obese or of normal weight over two time points in the 5 years prior to the brain scan. In a post-hoc preliminary analysis, we compared scores for obese and normal weight people who completed the trail-making task.

SUBJECTS:

A total of 292 subjects were examined following exclusions (for example, owing to dementia, stroke and cortical infarcts) from the Prospective Investigation of the Vasculature in Uppsala Seniors cohort with a body mass index of normal weight (<25 kg m⁻²) or obese (⩾30 kg m⁻²).

RESULTS:

People who were obese had significantly smaller total brain volumes and specifically, significantly reduced total gray matter (GM) volume (GMV) (with no difference in white matter or cerebrospinal fluid). Initial exploratory whole brain uncorrected analysis revealed that people who were obese had significantly smaller GMV in the bilateral supplementary motor area, bilateral dorsolateral prefrontal cortex (DLPFC), left inferior frontal gyrus and left postcentral gyrus. Secondary more stringent corrected analyses revealed a surviving cluster of GMV difference in the left DLPFC. Finally, post-hoc contrasts of scores on the trail-making task, which is linked to DLPFC function, revealed that obese people were significantly slower than those of normal weight.

CONCLUSION:

These findings suggest that in comparison with normal weight, people who are obese have smaller GMV, particularly in the left DLPFC. Our results may provide evidence for a potential working memory mechanism for the cognitive suppression of appetite that may lower the risk of developing obesity in later life.

Pittsburgh compound-B and Alzheimer's disease biomarkers in CSF, plasma and urine: An exploratory study

BACKGROUND

The positron emission tomography (PET) radiotracer Pittsburgh Compound-B (PIB) is an in vivo ligand for measuring beta-amyloid (Abeta) load. Associations between PET PIB and cerebrospinal fluid (CSF) Abeta1-42 and apolipoprotein E epsilon4 (APOE epsilon4) have been observed in several studies, but the relations between PIB uptake and other biomarkers of Alzheimer's disease (AD) are less investigated.

METHOD

PET PIB, PET 18Fluoro-2-deoxy-D-glucose and different AD biomarkers were measured twice in CSF, plasma and urine 12 months apart in 10 patients with a clinical diagnosis of mild to moderate AD.

RESULTS

PIB retention was constant over 1 year, inversely related to low CSF Abeta1-42 (p = 0.01) and correlated positively to the numbers of the APOE epsilon4 allele (0, 1 or 2) (p = 0.02). There was a relation between mean PIB retention and CSF ApoE protein (r = -0.59, p = 0.07), and plasma cystatin C (r = -0.56, p = 0.09).

CONCLUSION

PIB retention is strongly related to CSF Abeta1-42, and to the numbers of the APOE epsilon4 allele.

Glucose metabolism and the risk of Alzheimer's disease and dementia: a population-based 12 year follow-up study in 71-year-old men

AIMS/HYPOTHESIS

Accumulating evidence suggests that diabetes increases the risk of dementia, but few studies have addressed possible mechanisms underlying this relationship. The aim of our study was to investigate the longitudinal association of glucose metabolism, insulin secretion and insulin action with the development of Alzheimer's disease and vascular dementia.

METHODS

The Uppsala Longitudinal Study of Adult Men is an ongoing observational study in Sweden in which 1,125 men aged 71 years and free from dementia underwent an OGTT and a euglycaemic insulin clamp between 1990 and 1995. During a median follow-up of 12 years, 257 persons developed dementia or cognitive impairment, of whom 81 had Alzheimer's disease and 26 vascular dementia. Associations were analysed with the Cox proportional hazards method.

RESULTS

Low early insulin response to oral glucose challenge, but not low insulin sensitivity, was associated with a higher risk of Alzheimer's disease (HR for 1 SD decrease 1.32; 95% CI 1.02, 1.69) after adjustment for diabetes, blood pressure, body mass index, cholesterol, smoking and educational level. Low insulin sensitivity was associated with a higher risk of vascular dementia (HR for 1 SD decrease 1.55; 95% CI 1.02, 2.35), but not after multiple adjustments. Diabetes increased the risk of any dementia and cognitive impairment by 63%.

CONCLUSIONS/INTERPRETATION

In this community-based study, low early insulin response was associated with increased risk of subsequent Alzheimer's disease, whereas low insulin sensitivity was not. Vascular dementia was not related to early insulin response. We suggest that glucometabolic disturbances are linked differentially to the pathogenesis of these two main dementia subtypes.

Serum cystatin C and the risk of Alzheimer disease in elderly men

BACKGROUND

Multiple lines of research suggest that increased cystatin C activity in the brain protects against the development of Alzheimer disease (AD).

METHODS

Serum cystatin C levels were analyzed at two examinations of the Uppsala Longitudinal Study of Adult Men, a longitudinal, community-based study of elderly men (age 70 years, n = 1,153 and age 77 years, n = 761, a subset of the age 70 examination). Cox regressions were used to examine associations between serum cystatin C and incident AD. AD cases were identified by cognitive screening and comprehensive medical chart review in all subjects.

RESULTS

On follow-up (median 11.3 years), 82 subjects developed AD. At age 70 years, lower cystatin C was associated with higher risk of AD independently of age, APOE4 genotype, glomerular filtration rate, diabetes, hypertension, stroke, cholesterol, body mass index, smoking, education level, and plasma amyloid-beta protein 40 and 42 levels (hazard ratio [HR] for lowest [<1.12 micromol/L] vs highest [>1.30 micromol/L] tertile = 2.67, 95% CI 1.22-5.83, p < 0.02). The results were similar at age 77 years (43 participants developed AD during follow-up). Furthermore, a 0.1-mumol/L decrease of cystatin C between ages 70 and 77 years was associated with a 29% higher risk of incident AD (HR 1.29, 95% CI 1.03-1.63, p < 0.03).

CONCLUSIONS

Low levels of serum cystatin C precede clinically manifest Alzheimer disease (AD) in elderly men free of dementia at baseline and may be a marker of future risk of AD. These findings strengthen the evidence for a role for cystatin C in the development of clinical AD.

Impaired insulin secretion increases the risk of Alzheimer disease

OBJECTIVE

Subjects with diabetes are reported to have an increased risk of dementia and cognitive impairment. However, the underlying causes remain unknown. We investigated the longitudinal associations between midlife insulin secretion, glucose metabolism, and the subsequent development of Alzheimer disease (AD) and dementia.

METHODS

The population-based Uppsala Longitudinal Study of Adult Men started 1970 when the 2,322 participants were 50 years old. Investigation at baseline included determinations of acute insulin response and glucose tolerance using the IV glucose tolerance test and Homeostasis Model Assessment insulin resistance index. During a median follow up of 32 years, 102 participants were diagnosed with AD, 57 with vascular dementia, and 394 with any dementia or cognitive impairment. Associations were analyzed using Cox proportional hazard models.

RESULTS

A low insulin response at baseline was associated with a higher cumulative risk of AD (hazard ratio for 1 SD decrease, 1.31; 95% CI, 1.10-1.56) also after adjustment for age, systolic blood pressure, body mass index, serum cholesterol, smoking, education level, and insulin resistance. This association was stronger in subjects without the APOE epsilon4 allele. Impaired glucose tolerance increased the risk of vascular dementia (hazard ratio for 1 SD decrease, 1.45; 95% CI, 1.05-2.00) but not AD. Impaired insulin secretion, glucose intolerance, and estimates of insulin resistance were all associated with higher risk of any dementia and cognitive impairment.

CONCLUSIONS

In this longitudinal study, impaired acute insulin response at midlife was associated with an increased risk of Alzheimer disease (AD) up to 35 years later suggesting a causal link between insulin metabolism and the pathogenesis of AD.

Reduction of phosphorylated tau during memantine treatment of Alzheimer's disease

BACKGROUND

Memantine is a moderate affinity N-methyl-D-aspartate receptor antagonist approved for treatment of Alzheimer's disease (AD). In AD, tau is abnormally hyperphosphorylated. However, no significant changes of phosphorylated tau levels in CSF are found at follow-up in studies with AD patients. It has been shown in vitro that memantine reverse induced abnormal hyperphosphorylation of tau in hippocampal neurons of rats.

METHODS

Eleven AD patients were examined with cognitive tests and interviews of relatives. CSF analyses were performed before starting treatment with memantine as well as after 1 year.

RESULTS

A statistically significant reduction of CSF phosphorylated tau at the 1-year follow-up was seen, from median 126 (interquartile range 107-153) to 108 (88-133) ng/l (p = 0.018). No statistically significant differences of total tau or Abeta42 were found.

CONCLUSION

The results may reflect effects of memantine on a key pathological feature in AD in line with previous in vitro findings.

Tacrine and rate of progression in Alzheimer's disease--relation to ApoE allele genotype

Today, cognitive impairment can be successfully treated with acetylcholine esterase inhibitors (AChE-I) in many, but not all, patients with Alzheimer's disease (AD). To investigate the relation between tacrine treatment, inheritance of ApoE epsilon4 alleles, and rate of progression, the differences in MMSE and CIBIC scores (efficacy parameters) after 6 and 12 months of tacrine (an AChE-I) treatment were investigated in 145 AD patients. Of these, 84 were ApoE epsilon4-positive (ApoE4) and 61 were ApoE epsilon4-negative (ApoE2-3). No differences were found after 6 months of treatment, but after 12 months the CIBIC scores revealed that the ApoE4 patients had declined more than the ApoE2-3 patients (p < 0.05). No differences were found for the last 6 months of treatment. The results primarily suggest a faster rate of decline in the ApoE4 AD compared to the ApoE2-3, but may also reflect that ApoE epsilon4 genotype inheritance is a negative predictor of treatment effect of tacrine in AD patients.

Education, lifestyle factors and mortality from cardiovascular disease and cancer. A 25-year follow-up of Swedish 50-year-old men

BACKGROUND

There is a well-established inverse relation between education and mortality from cardiovascular disease and cancer. The reasons for this are still in part unclear. We aimed to investigate whether differences in traditional vascular risk factors, adult height, physical activity, and biomarkers of fatty acid and antioxidant intake, could explain this association.

METHODS

In all, 2301 50-year-old men in Uppsala, Sweden (82% of the background population) were examined with regard to educational level, blood pressure, blood glucose, body mass index, serum lipids, smoking, body height, physical activity, serum beta carotene, alpha tocopherol, selenium, and serum fatty acids in cholesterol esters. Cause-specific mortality was registered 25 years later.

RESULTS

Low education was associated with a higher rate of mortality from cardiovascular disease (crude relative risk [RR] = 1.67, 95% CI : 1.17-2.39), and from cancer (crude RR = 1.94, 95% CI : 1.21-3.10), compared to high educational attainment. Men with high education had an overall more beneficial risk factor profile concerning traditional cardiovascular risk factors, physical activity, and biomarkers of dietary intake of antioxidants and fat. After adjustment for all examined risk factors, the inverse gradient between education and cardiovascular mortality disappeared (RR in low education = 1.01. 95% CI : 0.67-1.52). Controlling for smoking, physical activity and dietary biomarkers explained less than half of the excess cancer mortality in the lower educational groups. Smoking (adjusted RR = 1.89, 95% CI : 1.37-2.61), and high proportions of palmitoleic acid in serum cholesterol esters (adjusted RR per 1 SD = 1.39, 95% CI : 1.07-1.82) predicted cancer mortality, independently of all other factors. There were no independent relations between serum antioxidants and mortality.

CONCLUSIONS

These data indicate that modifiable lifestyle factors mediate the inverse gradient between education and death from cerebro- and cardiovascular disease. Smoking, physical activity and dietary factors explained half of the excess cancer mortality in lower educated groups. Further studies are needed to explore the proposed association between palmitoleic acid, a marker of high intake of animal and dairy fat, and cancer.

[Harmonization of dementia diagnoses--a necessary quality assurance]

Classification and registration of diseases is necessary in order to monitor the proliferation of diseases in a population. Despite the presence of an international framework for classification of diseases (ICD 10) which has been approved by the Swedish authorities, the guidelines provided are not observed in the area of dementia diseases. Different diagnoses can be used to describe the same condition, and "dementia unspecified" is sometimes employed when a specified diagnosis could have been used. In order to refine consensus regarding the use of different diagnoses in the dementia field, representatives for the Swedish University hospitals and medical faculties propose a unified description of a limited number of dementia diagnoses.

The association between low diastolic blood pressure in middle age and cognitive function in old age. A population-based study

BACKGROUND

previous longitudinal studies have shown an inverse relation between blood pressure and cognitive function.

OBJECTIVE

to determine the association between mid-life blood pressure and performance in different areas of cognitive function in late life.

SUBJECTS AND METHODS

we recruited 502 men, aged 69-74 years, from a population-based cohort in Uppsala, Sweden. Blood pressure had been measured at age 50 and we examined performance in 13 psychometric tests about 20 years later.

RESULTS

after the 39 men with a previous stroke had been excluded, there was an inverse relation between diastolic blood pressure at age 50 and performance 20 years later in the digit span test, the trail-making tests and in verbal fluency. The relationships were significant, independently of age, education and previous occupational level. Men within the lowest category of diastolic blood pressure (< or = 70 mmHg, n = 59) showed the best results. Baseline blood pressure levels were not linked to performance in tasks on vocabulary, verbal learning and memory or figure copying.

CONCLUSIONS

low blood pressure in mid-life indicates a low long-term cerebrovascular risk and is associated with higher late-life performance in cognitive tests that mainly assess subcortico-frontal cognitive functions.

Epidemiological and clinical studies on insulin resistance and diabetes

In Uppsala, extensive epidemiological and clinical studies on insulin resistance and diabetes have been ongoing for the past 30 years. A prospective cohort study of men born 1920-24, living in Uppsala County, was initiated during 1969-74 (the Uppsala Longitudinal Study of Adult Men, ULSAM). Risk factors for cardiovascular disease were examined in 2,322 men, and re-examinations have been performed every 10 years. At the first follow-up, when the men were 60 years old, insulin resistance was found to be a risk factor for development of hypertension and diabetes. In addition, treatment with antihypertensive medication was an independent risk factor for development of diabetes. These findings resulted in a series of clinical studies on metabolic effects of antihypertensive agents. At the second follow-up, when the men were 70 years old, the development of hypertension and diabetes was once again in focus, but at this time, cross-sectional and prospective studies of other cardiovascular determinants, such as circadian blood pressure pattern, left ventricular geometry and function, muscle morphology, ion status, fibrinolysis and cognitive function, were also performed. The cohort has furthermore been linked to the Swedish census and hospital discharge and cause of death registries, it has been used for studies on relationships between birth weight and cardiovascular disease, and genetic analyses have been performed, taking advantage of the long observation time obtained in this cohort. The cohort is currently being re-examined for the third time, and will hopefully continue to provide valuable information on the epidemiology of diabetes and cardiovascular disease in the future.

Atrial fibrillation is an independent determinant of low cognitive function: a cross-sectional study in elderly men

BACKGROUND AND PURPOSE

Cerebrovascular disease is increasingly recognized as a cause of dementia and cognitive decline. We have previously reported an association between hypertension and diabetes and low cognitive function in the elderly. Atrial fibrillation is another main risk factor for cerebrovascular disease. The aim of this study was to investigate whether atrial fibrillation is associated with low cognitive function in elderly men with and without previous manifest stroke.

METHODS

This was a cross-sectional study based on a cohort of 952 community-living men, aged 69 to 75 years, in Uppsala, Sweden. Cognitive functions were assessed by the Mini-Mental State Examination and the Trail Making Tests, and a composite z score was calculated. The relation between atrial fibrillation and cognitive z score was analyzed, with stroke and other vascular risk factors taken into account.

RESULTS

All analyses were adjusted for age, education, and occupational level. Men with atrial fibrillation (n=44) had lower mean adjusted cognitive z scores (-0.26+/-0.11) than men without atrial fibrillation (+0.14+/-0.03; P=0.0003). The exclusion of stroke patients did not alter this relationship; the mean cognitive z score was -0.24+/-0.12 in the 36 men with atrial fibrillation and +0.17+/-0.03 in those without atrial fibrillation (P=0.0004), corresponding to a difference of 0.4 SDs between groups. Adjustments for 24-hour diastolic blood pressure and heart rate, diabetes, and ejection fraction did not change this relationship. Men with atrial fibrillation who were treated with digoxin (n=27) performed markedly better (-0.05+/-0.21) than those without treatment (n=9; -1.14+/-0.34; adjusted P=0.0005). Previous myocardial infarction was not associated with impaired cognitive results.

CONCLUSIONS

In these community-living elderly men, we found an association between atrial fibrillation and low cognitive function independent of stroke, high blood pressure, and diabetes. Interventional studies are needed to answer the question of whether optimal treatment of atrial fibrillation may prevent or postpone cognitive decline and dementia.

Hypertension is related to cognitive impairment: a 20-year follow-up of 999 men

Recent findings of a linkage between high blood pressure (BP) and later development of dementia have given new prospects on cerebral target-organ damage in hypertension and have added substance to the concept of "preventable senility." The aim of this study was to analyze the impact of hypertension, circadian BP profile, and disturbed glucose metabolism on cognitive function. The study population consisted of 999 seventy-year-old men from a population-based cohort study in Uppsala, Sweden, followed with respect to cardiovascular risk factors since the age of 50 years. At the age of 70, 24-hour ambulatory BP was monitored together with measurements of insulin sensitivity, glucose tolerance, serum lipids, and lipoproteins. Cognitive function was assessed by the Mini-Mental State Examination and the Trail-Making Test. High diastolic BP at baseline predicted later impaired cognitive performance, even after excluding men with a previous stroke (n = 70). Cross-sectional measurements at age 70 showed that high 24-hour BP, nondipping, insulin resistance, and diabetes all were related to low cognitive function. The relationships between hypertension and cognitive impairment were strongest in untreated men. These data from a general population of healthy elderly men indicate that hypertension and associated metabolic disturbances might be susceptibility factors for cognitive disorders. The findings add support to possibilities of intervention in early stages in cognitive decline, ie, before manifest dementia.

How do we treat, or not treat, high blood pressure in the oldest old? A practice study in Swedish geriatricians

No clear guidelines exist for the treatment of hypertension in the oldest old (age 80+). While on the one hand the benefits of antihypertensive treatment in stroke prevention are greatest in very old people, on the other hand the adverse effects of treatment are more frequent in these frail, elderly patients. What is optimum blood pressure (BP) in healthy old patients, and in old patients with stroke or dementia? This study aimed to describe physicians opinions regarding BP treatment in geriatric patients. Of 462 Swedish geriatricians sent a postal questionnaire, 350 responded. In answer to the question what stage they would initiate treatment in a healthy, 82-year-old female patient, more than half responded that they would start treatment at higher BP levels (systolic BP >180 mmHg or diastolic BP >100 mmHg) than is recommended for younger elderly. Opinion varied on ideal BP in the case of a recent minor stroke, or dementia. Findings from epidemiological studies concerning the relations between BP and stroke and dementia are discussed. We conclude that further research is needed in this area.

Cognitive function, vascular risk factors and education. A cross-sectional study based on a cohort of 70-year-old men

OBJECTIVES

A low level of education is associated with an increased risk of developing a dementia disorder, as well as with a higher risk of cardiovascular disease. The aim of this study was to investigate the association between education and cardiovascular risk factors, and to study the relation between these factors and cognitive function in elderly men.

DESIGN

Cross-sectional population-based study.

SETTING

Uppsala, Sweden.

SUBJECTS

504 men aged 69-74 years, participants in a longitudinal health survey concerning cardiovascular risk factors.

MAIN OUTCOME MEASURE

Cognitive function as measured by a composite score of 13 standard psychometric tests.

RESULTS

A low level of education was associated with poorer cognitive performance, as well as with obesity, smoking, diabetes, high concentrations of serum triglycerides and plasma fibrinogen. In the entire cohort, subjects with obesity, smoking, diabetes or hypertriglyceridaemia showed impaired cognitive test results, independent of socio-economic factors. When stroke cases were excluded, obesity and smoking were still related to impaired cognitive function.

CONCLUSIONS

Smoking and obesity with associated metabolic disturbances are inversely related both to educational level and to cognitive function. Cognitive decline of vascular origin is potentially preventable by treatment of risk factors. The question of whether the increased vascular risk contributes to the higher prevalence of cognitive disorders in individuals with low socio-economic status, needs to be further evaluated in longitudinal population-based studies.

Peripheral glucose metabolism and insulin sensitivity in Alzheimer's disease

Twenty-four patients with Alzheimer's disease and matched controls were examined with reference to metabolic parameters such as peripheral insulin and glucose metabolism, serum lipid concentrations and blood pressure levels. Blood glucose levels and insulin response were measured during an intravenous glucose tolerance test and peripheral insulin sensitivity was estimated with the hyperinsulinemic euglycemic clamp technique. There were no differences recorded between the two groups in glucose metabolism, triglyceride, cholesterol or HDL-cholesterol levels. The patients with Alzheimer's disease had significantly lower blood pressure levels, which partly could be explained by ongoing treatment with neuroleptics and antidepressives. Previous findings of higher insulin levels in Alzheimer's disease could not be verified.