Inhibiting tumor necrosis factor-α before amyloidosis prevents synaptic deficits in an Alzheimer's disease model

Deficits in synaptic structure and function are likely to underlie cognitive impairments in Alzheimer's disease. While synaptic deficits are commonly found in animal models of amyloidosis, it is unclear how amyloid pathology may impair synaptic functions. In some amyloid mouse models of Alzheimer's disease, however, synaptic deficits are preceded by hyperexcitability of glutamate synapses. In the amyloid transgenic mouse model TgCRND8, we therefore investigated whether early enhancement of glutamatergic transmission was responsible for development of later synaptic deficits. Hippocampi from 1-month-old TgCRND8 mice revealed increased basal transmission and plasticity of glutamate synapses that was related to increased levels of tumor necrosis factor α (TNFα). Treating these 1-month-old mice for 4 weeks with the TNFα inhibitor XPro1595 prevented synaptic deficits otherwise apparent at the age of 6 months. In this mouse model at least, reversing the hyperexcitability of glutamate synapses via TNFα blockade before the onset of amyloid plaque formation prevented later synaptic deficits.

Test-retest resting-state fMRI in healthy elderly persons with a family history of Alzheimer's disease

We present a test-retest dataset of resting-state fMRI data obtained in 80 cognitively normal elderly volunteers enrolled in the “Pre-symptomatic Evaluation of Novel or Experimental Treatments for Alzheimer's Disease” (PREVENT-AD) Cohort. Subjects with a family history of Alzheimer's disease in first-degree relatives were recruited as part of an on-going double blind randomized clinical trial of Naproxen or placebo. Two pairs of scans were acquired ~3 months apart, allowing the assessment of both intra- and inter-session reliability, with the possible caveat of treatment effects as a source of inter-session variation. Using the NeuroImaging Analysis Kit (NIAK), we report on the standard quality of co-registration and motion parameters of the data, and assess their validity based on the spatial distribution of seed-based connectivity maps as well as intra- and inter-session reliability metrics in the default-mode network. This resource, released publicly as sample UM1 of the Consortium for Reliability and Reproducibility (CoRR), will benefit future studies focusing on the preclinical period preceding the appearance of dementia in Alzheimer's disease.

Alzheimer amyloid peptide aβ42 regulates gene expression of transcription and growth factors

The pathogenesis of Alzheimer's disease (AD) is characterized by the aggregation of amyloid-β (Aβ) peptides leading to deposition of senile plaques and a progressive decline of cognitive functions, which currently remains the main criterion for its diagnosis. Robust biomarkers for AD do not yet exist, although changes in the cerebrospinal fluid levels of tau and Aβ represent promising candidates in addition to brain imaging and genetic risk profiling. Although concentrations of soluble Aβ42 correlate with symptoms of AD, less is known about the biological activities of Aβ peptides which are generated from the amyloid-β protein precursor. An unbiased DNA microarray study showed that Aβ42, at sub-lethal concentrations, specifically increases expression of several genes in neuroblastoma cells, notably the insulin-like growth factor binding proteins 3 and 5 (IGFBP3/5), the transcription regulator inhibitor of DNA binding, and the transcription factor Lim only domain protein 4. Using qRT-PCR, we confirmed that mRNA levels of the identified candidate genes were exclusively increased by the potentially neurotoxic Aβ42 wild-type peptide, as both the less toxic Aβ40 and a non-toxic substitution peptide Aβ42 G33A did not affect mRNA levels. In vivo immunohistochemistry revealed a corresponding increase in both hippocampal and cortical IGFBP5 expression in an AD mouse model. Proteomic analyses of human AD cerebrospinal fluid displayed increased in vivo concentrations of IGFBPs. IGFBPs and transcription factors, as identified here, are modulated by soluble Aβ42 and may represent useful early biomarkers.

Sleep-Wake Cycle Dysfunction in the TgCRND8 Mouse Model of Alzheimer's Disease: From Early to Advanced Pathological Stages

In addition to cognitive decline, individuals affected by Alzheimer’s disease (AD) can experience important neuropsychiatric symptoms including sleep disturbances. We characterized the sleep-wake cycle in the TgCRND8 mouse model of AD, which overexpresses a mutant human form of amyloid precursor protein resulting in high levels of β-amyloid and plaque formation by 3 months of age. Polysomnographic recordings in freely-moving mice were conducted to study sleep-wake cycle architecture at 3, 7 and 11 months of age and corresponding levels of β-amyloid in brain regions regulating sleep-wake states were measured. At all ages, TgCRND8 mice showed increased wakefulness and reduced non-rapid eye movement (NREM) sleep during the resting and active phases. Increased wakefulness in TgCRND8 mice was accompanied by a shift in the waking power spectrum towards fast frequency oscillations in the beta (14-20 Hz) and low gamma range (20-50 Hz). Given the phenotype of hyperarousal observed in TgCRND8 mice, the role of noradrenergic transmission in the promotion of arousal, and previous work reporting an early disruption of the noradrenergic system in TgCRND8, we tested the effects of the alpha-1-adrenoreceptor antagonist, prazosin, on sleep-wake patterns in TgCRND8 and non-transgenic (NTg) mice. We found that a lower dose (2 mg/kg) of prazosin increased NREM sleep in NTg but not in TgCRND8 mice, whereas a higher dose (5 mg/kg) increased NREM sleep in both genotypes, suggesting altered sensitivity to noradrenergic blockade in TgCRND8 mice. Collectively our results demonstrate that amyloidosis in TgCRND8 mice is associated with sleep-wake cycle dysfunction, characterized by hyperarousal, validating this model as a tool towards understanding the relationship between β-amyloid overproduction and disrupted sleep-wake patterns in AD.

Use of diuretics is associated with reduced risk of Alzheimer's disease: the Cache County Study

Although the use of antihypertensive medications has been associated with reduced risk of Alzheimer's disease (AD), it remains unclear which class provides the most benefit. The Cache County Study of Memory Health and Aging is a prospective longitudinal cohort study of dementing illnesses among the elderly population of Cache County, Utah. Using waves I to IV data of the Cache County Study, 3417 participants had a mean of 7.1 years of follow-up. Time-varying use of antihypertensive medications including different class of diuretics, angiotensin converting enzyme inhibitors, β-blockers, and calcium channel blockers was used to predict the incidence of AD using Cox proportional hazards analyses. During follow-up, 325 AD cases were ascertained with a total of 23,590 person-years. Use of any antihypertensive medication was associated with lower incidence of AD (adjusted hazard ratio [aHR], 0.77; 95% confidence interval [CI], 0.61-0.97). Among different classes of antihypertensive medications, thiazide (aHR, 0.7; 95% CI, 0.53-0.93), and potassium-sparing diuretics (aHR, 0.69; 95% CI, 0.48-0.99) were associated with the greatest reduction of AD risk. Thiazide and potassium-sparing diuretics were associated with decreased risk of AD. The inverse association of potassium-sparing diuretics confirms an earlier finding in this cohort, now with longer follow-up, and merits further investigation.

Screening by telephone in the Alzheimer's disease anti-inflammatory prevention trial

Compared with in-person assessment methods, telephone screening for dementia and other cognitive syndromes may improve efficiency of large population studies or prevention trials. We used data from the Alzheimer's Disease Anti-Inflammatory Prevention Trial to compare performance of a four-test Telephone Assessment Battery (TAB) that included the Telephone Interview for Cognitive Status (TICS) to that of a traditional in-person Cognitive Assessment Battery. Among 1,548 elderly participants with valid telephone and in-person screening results obtained within 90 days of each other, 225 persons were referred for a full cognitive diagnostic evaluation that was completed within six months of screening. Drawing on results from this panel of 225 individuals, we used the Capture-Recapture method to estimate population numbers of cognitively impaired participants. The latter estimates enabled us to compare the performance characteristics of the two screening batteries at specified cut-offs for detection of dementia and milder forms of impairment. Although our results provide relatively imprecise estimates of the performance characteristics of the two batteries, a comparison of their relative performance suggests that, at selected cut-off points, the TAB produces results broadly comparable to in-person screening and may be slightly more sensitive in detecting mild impairment. TAB performance characteristics also appeared slightly better than those of the TICS alone. Given its benefits in time and cost when screening for cognitive disorders, telephone screening should be considered for large samples.

Three Cardinal Lessons from ADAPT - 10 Years on

The Alzheimer's Disease Anti-inflammatory Prevention Trial was a placebo-controlled three-arm pharmaco-prevention trial of the non-steroidal anti-inflammatory drugs naproxen sodium and celecoxib for prevention of incident Alzheimer's disease (AD) dementia in older (aged 70 and over) adults. Although subjects were at increased risk of symptoms because of a firstdegree family history, they were meant to be cognitively healthy at enrollment. ADAPT encountered several problems that resulted in the termination of its treatments after only two years on average. Interim results were complex but potentially interesting. In the end, however, the results were null. We describe the complications that prevented ADAPT from achieving conclusive results, and suggest that these could have been avoided if the trial design and execution had been better guided by preliminary data. We believe such data should be available before beginning further ambitious phase III trials of this sort, and we suggest a broad method by which such data can be accumulated with reasonable economy.

A hierarchy of predictors for dementia-free survival in old-age: results of the AgeCoDe study

OBJECTIVE

Progression from cognitive impairment (CI) to dementia is predicted by several factors, but their relative importance and interaction are unclear.

METHOD

We investigated numerous such factors in the AgeCoDe study, a longitudinal study of general practice patients aged 75+. We used recursive partitioning analysis (RPA) to identify hierarchical patterns of baseline covariates that predicted dementia-free survival.

RESULTS

Among 784 non-demented patients with CI, 157 (20.0%) developed dementia over a follow-up interval of 4.5 years. RPA showed that more severe cognitive compromise, revealed by a Mini-Mental State Examination (MMSE) score < 27.47, was the strongest predictor of imminent dementia. Dementia-free survival time was shortest (mean 2.4 years) in such low-scoring patients who also had impaired instrumental activities of daily living (iADL) and subjective memory impairment with related worry (SMI-w). Patients with identical characteristics but without SMI-w had an estimated mean dementia-free survival time of 3.8 years, which was still shorter than in patients who had subthreshold MMSE scores but intact iADL (4.2-5.2 years).

CONCLUSION

Hierarchical patterns of readily available covariates can predict dementia-free survival in older general practice patients with CI. Although less widely appreciated than other variables, iADL impairment appears to be an especially noteworthy predictor of progression to dementia.

Variants in PPP3R1 and MAPT are associated with more rapid functional decline in Alzheimer's disease: the Cache County Dementia Progression Study

BACKGROUND

Single-nucleotide polymorphisms (SNPs) located in the gene encoding the regulatory subunit of the protein phosphatase 2B (PPP3R1, rs1868402) and the microtubule-associated protein tau (MAPT, rs3785883) gene were recently associated with higher cerebrospinal fluid (CSF) tau levels in samples from the Knight Alzheimer's Disease Research Center at Washington University (WU) and Alzheimer's Disease Neuroimaging Initiative (ADNI). In these same samples, these SNPs were also associated with faster functional decline, or progression of Alzheimer's disease (AD) as measured by the Clinical Dementia Rating sum of boxes scores (CDR-sb). We attempted to validate the latter association in an independent, population-based sample of incident AD cases from the Cache County Dementia Progression Study (DPS).

METHODS

All 92 AD cases from the DPS with a global CDR-sb ≤1 (mild) at initial clinical assessment who were later assessed on CDR-sb data on at least two other time points were genotyped at the two SNPs of interest (rs1868402 and rs3785883). We used linear mixed models to estimate associations between these SNPs and CDR-sb trajectory. All analyses were performed using Proc Mixed in SAS.

RESULTS

Although we observed no association between rs3785883 or rs1868402 alone and change in CDR-sb (P > .10), there was a significant association between a combined genotype model and change in CDR-sb: carriers of the high-risk genotypes at both loci progressed >2.9 times faster than noncarriers (P = .015). When data from DPS were combined with previously published data from WU and ADNI, change in CDR-sb was 30% faster for each copy of the high-risk allele at rs3785883 (P = .0082) and carriers of both high-risk genotypes at both loci progressed 6 times faster (P < .0001) than all others combined.

CONCLUSIONS

We replicate a previous report by Cruchaga et al that specific variations in rs3785883 and rs1868402 are associated with accelerated progression of AD. Further characterization of this association will provide a better understanding of how genetic factors influence the rate of progression of AD and could provide novel insights into preventative and therapeutic strategies.

Hormone therapy and Alzheimer disease dementia: new findings from the Cache County Study

OBJECTIVES

Observational studies suggest reduced risk of Alzheimer disease (AD) in users of hormone therapy (HT), but trials show higher risk. We examined whether the association of HT with AD varies with timing or type of HT use.

METHODS

Between 1995 and 2006, the population-based Cache County Study followed 1,768 women who had provided a detailed history on age at menopause and use of HT. During this interval, 176 women developed incident AD. Cox proportional hazard models evaluated the association of HT use with AD, overall and in relation to timing, duration of use, and type (opposed vs unopposed) of HT.

RESULTS

Women who used any type of HT within 5 years of menopause had 30% less risk of AD (95% confidence interval 0.49-0.99), especially if use was for 10 or more years. By contrast, AD risk was not reduced among those who had initiated HT 5 or more years after menopause. Instead, rates were increased among those who began "opposed" estrogen-progestin compounds within the 3 years preceding the Cache County Study baseline (adjusted hazard ratio 1.93; 95% confidence interval 0.94-3.96). This last hazard ratio was similar to the ratio of 2.05 reported in randomized trial participants assigned to opposed HT.

CONCLUSIONS

Association of HT use and risk of AD may depend on timing of use. Although possibly beneficial if taken during a critical window near menopause, HT (especially opposed compounds) initiated in later life may be associated with increased risk. The relation of AD risk to timing and type of HT deserves further study.

Latent class-derived subgroups of depressive symptoms in a community sample of older adults: the Cache County Study

OBJECTIVE

We sought to identify possible subgroups of elders that varied in depressive symptomatology and to examine symptom patterns and health status differences between subgroups.

METHODS

The Cache County memory study is a population-based epidemiological study of dementia with 5092 participants. Depressive symptoms were measured with a modified version of the diagnostic interview schedule-depression. There were 400 nondemented participants who endorsed currently (i.e., in the past 2 weeks) experiencing at least one of the three "gateway" depressive symptoms and then completed a full depression interview. Responses to all nine current depressive symptoms were modeled using the latent class analysis.

RESULTS

Three depression subgroups were identified: a significantly depressed subgroup (62%), with the remainder split evenly between a subgroup with low probability of all symptoms (21%), and a subgroup with primarily psychomotor changes, sleep symptoms, and fatigue (17%). Latent class analysis derived subgroups of depressive symptoms and Diagnostic and statistical manual of mental disorders, fourth edition depression diagnostic group were nonredundant. Age, gender, education, marital status, early or late onset, number of episodes, current episode duration, and functional status were not significant predictors of depression subgroup. The first subgroup was more likely to be recently bereaved and had less physical health problems, whereas the third subgroup were less likely to be using antidepressants compared with the second subgroup.

CONCLUSIONS

There are distinct subgroups of depressed elders, which are not redundant with the Diagnostic and statistical manual of mental disorders, fourth edition classification scheme, offering an alternative diagnostic approach to clinicians and researchers. Future work will examine whether these depressive symptom profiles are predictive of incident dementia and earlier mortality.

Lifestyle behavior pattern is associated with different levels of risk for incident dementia and Alzheimer's disease: the Cache County study

OBJECTIVES

To identify distinct behavioral patterns of diet, exercise, social interaction, church attendance, alcohol consumption, and smoking and to examine their association with subsequent dementia risk.

DESIGN

Longitudinal, population-based dementia study.

SETTING

Rural county in northern Utah, at-home evaluations.

PARTICIPANTS

Two thousand four hundred ninety-one participants without dementia (51% male, average age 73.0 ± 5,7; average education 13.7 ± 4.1 years) initially reported no problems in activities of daily living and no stroke or head injury within the past 5 years.

MEASUREMENTS

Six dichotomized lifestyle behaviors were examined (diet: high ≥ median on the Dietary Approaches to Stop Hypertension scale; exercise: ≥5 h/wk of light activity and at least occasional moderate to vigorous activity; church attendance: attending church services at least weekly; social Interaction: spending time with family and friends at least twice weekly; alcohol: currently drinking alcoholic beverages ≥ 2 times/wk; nonsmoker: no current use or fewer than 100 cigarettes ever). Latent class analysis (LCA) was used to identify patterns among these behaviors. Proportional hazards regression modeled time to dementia onset as a function of behavioral class, age, sex, education, and apolipoprotein E status. Follow-up averaged 6.3 ± 5.3 years, during which 278 cases of incident dementia (200 Alzheimer's disease (AD)) were diagnosed.

RESULTS

LCA identified four distinct lifestyle classes. Unhealthy-religious (UH-R; 11.5%), unhealthy-nonreligious (UH-NR; 10.5%), healthy-moderately religious (H-MR; 38.5%), and healthy-very religious (H-VR; 39.5%). UH-NR (hazard ratio (HR) = 0.54, P = .028), H-MR (HR = 0.56, P = .003), and H-VR (HR = 0.58, P = .005) had significantly lower dementia risk than UH-R. Results were comparable for AD, except that UH-NR was less definitive.

CONCLUSION

Functionally independent older adults appear to cluster into subpopulations with distinct patterns of lifestyle behaviors with different levels of risk for subsequent dementia and AD.

Duke Twins Study of Memory in Aging in the NAS-NRC Twin Registry

The Duke Twins Study of Memory in Aging is an ongoing, longitudinal study of cognitive change and dementia in the population-based National Academy of Sciences-National Research Council (NAS-NRC) Twin Registry of World War II Male Veterans. The primary goal of this study has been to estimate the overall genetic and environmental contributions to dementia with a specific focus on Alzheimer's disease. An additional goal has been to examine specific genetic and environmental antecedents of cognitive decline and dementia. Since 1989, we have completed 4 waves of data collection. Each wave included a 2-phase telephone cognitive screening protocol, followed by an in-home standardized clinical assessment for those with suspected dementia. For many participants, we have obtained postmortem neuro-pathological confirmation of the diagnosis of dementia. In addition to data on cognition, we have also collected information on occupational history, medical history, medications and other lifetime experiences that may influence cognitive function in late life. We provide an overview of the study's methodology and describe the focus of recent research.

Atrial fibrillation and risk of dementia: a prospective cohort study

OBJECTIVES

To determine whether atrial fibrillation (AF) is associated with risk of incident dementia or Alzheimer's disease (AD), beyond its effect on stroke.

DESIGN

Prospective cohort study.

SETTING

An integrated healthcare delivery system.

PARTICIPANTS

A population-based sample of 3,045 community-dwelling adults aged 65 and older without dementia or clinical stroke followed from 1994 to 2008.

MEASUREMENTS

AF was identified from health plan electronic data using International Classification of Diseases, Ninth Revision, codes from inpatient and outpatient encounters. Covariates came from self-report, study measures, and health plan data. Participants were screened every 2 years using the Cognitive Abilities Screening Instrument (range 0-100), with detailed neuropsychological and clinical assessment of those scoring less than 86. A multidisciplinary consensus committee determined diagnoses of all-cause dementia and possible or probable AD using standard research criteria.

RESULTS

AF was present in 132 (4.3%) participants at baseline and was diagnosed in 370 (12.2%) more over a mean of 6.8 years of follow-up; 572 participants (18.8%) developed dementia (449 with AD). The adjusted hazard ratio associated with AF was 1.38 (95% confidence interval (CI)=1.10-1.73) for all-cause dementia and 1.50 (95% CI=1.16-1.94) for possible or probable AD. Results were similar for participants with and without clinically recognized stroke during follow-up and in sensitivity analyses examining only probable AD.

CONCLUSION

AF is associated with higher risk of developing AD and dementia. Future studies should examine whether specific treatments, including optimal anticoagulation, can decrease this risk.

Cognitive stimulation and cognitive and functional decline in Alzheimer's disease: the cache county dementia progression study

OBJECTIVES

To examine the association of engagement in cognitively stimulating activities with cognitive and functional decline in a population-based sample of incident Alzheimer's disease (AD).

METHOD

After diagnosis, 187 participants (65% females) were followed semiannually for a mean 2.7 (SD = 0.4) years. Mean age and education were 84.6 (SD = 5.8) and 13.2 (SD = 2.9) years. Caregivers enumerated cognitively stimulating leisure activities via the Lifestyle Activities Questionnaire. Cognition was assessed using the Mini-Mental State Examination and functional ability via the Clinical Dementia Rating sum of boxes. Linear mixed models tested the association between stimulating activities and change over time in each outcome. Covariates were demographic factors, estimated premorbid IQ, presence/absence of the APOE ε4 allele, duration of dementia, level of physical activity, and general health.

RESULTS

At initial assessment, 87% of participants were engaged in one or more stimulating activities, with mean (SD) activities = 4.0 (3.0). This number declined to 2.4 (2.0) at the final visit. There was a statistical interaction between dementia duration and number of activities in predicting rate of cognitive decline (p = .02) and overall functional ability (p = .006).

DISCUSSION

Active involvement in cognitively stimulating pursuits may be beneficial for persons with AD.

Histamine-2 receptor antagonist use and incident dementia in an older cohort

OBJECTIVES

To examine whether histamine-2 receptor antagonist medications (H2RAs) are associated with a lower incidence of all-cause dementia or Alzheimer's disease (AD), as some studies have suggested.

DESIGN

Prospective population-based cohort

SETTING

Group Health, an integrated health maintenance organization, Seattle, Washington.

PARTICIPANTS

Two thousand nine hundred twenty-three participants aged 65 and older without dementia at baseline, with initial recruitment between 1994 and 1996.

MEASUREMENTS

Follow-up occurred every 2 years to identify incident dementia and AD using standard criteria. Exposure to H2RAs was determined based on automated pharmacy data. Three aspects of exposure (time-varying) were examined based on standard daily dose (SDD): cumulative use, intensity of use (highest SDD in any prior 2-year window), and cumulative use stratified according to recency (1-3 years vs >3 years before).

RESULTS

Over a mean follow-up of 6.7 years, 585 subjects developed dementia (453 developed AD). Total cumulative exposure was not associated with dementia (P=.35; omnibus test) or AD (P=.23). The adjusted hazard ratios for the highest exposure category (>1,080 SDDs) compared with light or no use were 1.28 (95% confidence interval (CI)=0.95-1.72) for dementia and 1.41 (95% CI=1.00-1.97) for AD. Intensity of use was not associated with dementia (P=.39) or AD (P=.63). Examining exposure according to recent and distant cumulative use also showed no association with dementia (P=.11) or AD (P=.30).

CONCLUSION

No association was found between H2RA use and risk of all-cause dementia or AD using more-detailed and -extensive information about past H2RA use than any prior study.

Operationalizing diagnostic criteria for Alzheimer's disease and other age-related cognitive impairment-Part 1

In this article, the challenges faced by several noted population studies for Alzheimer dementia in operationalizing current clinical diagnostic criteria for Alzheimer's disease (AD) have been reviewed. Differences in case ascertainment, methodological biases, cultural and educational influences on test performance, inclusion of special populations such as underrepresented minorities and the oldest old, and detection of the earliest symptomatic stages of underlying AD have been considered. Classification of Alzheimer dementia may be improved by the incorporation of biomarkers for AD if the sensitivity, specificity, and predictive value of the biomarkers are established and if they are appropriate for epidemiological studies, as may occur should a plasma biomarker be developed. Biomarkers for AD could also facilitate studies of the interactions of various forms of neurodegenerative disorders with cerebrovascular disease, resulting in "mixed dementia".

Greater risk of dementia when spouse has dementia? The Cache County study

OBJECTIVES

To examine the effects of caring for a spouse with dementia on the caregiver's risk for incident dementia.

DESIGN

Population-based study of incident dementia in spouses of persons with dementia.

SETTING

Rural county in northern Utah.

PARTICIPANTS

Two thousand four hundred forty-two subjects (1,221 married couples) aged 65 and older.

MEASUREMENTS

Incident dementia was diagnosed in 255 subjects, with onset defined as age when subject met Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised, criteria for dementia. Cox proportional hazards regression tested the effect of time-dependent exposure to dementia in one's spouse, adjusted for potential confounders.

RESULTS

A subject whose spouse experienced incident dementia onset had a six times greater risk for incident dementia as subjects whose spouses were dementia free (hazard rate ratio (HRR)=6.0, 95% confidence interval (CI)=2.2-16.2, P<.001). In sex-specific analyses, husbands had higher risks (HRR=11.9, 95% CI=1.7-85.5, P=.01) than wives (HRR=3.7, 95% CI=1.2-11.6, P=.03).

CONCLUSION

The chronic and often severe stress associated with dementia caregiving may exert substantial risk for the development of dementia in spouse caregivers. Additional (not mutually exclusive) explanations for findings are discussed.

Nonsteroidal anti-inflammatory drugs are associated with increased neuritic plaques

OBJECTIVES

Observational and experimental studies suggest that nonsteroidal anti-inflammatory drugs (NSAIDs) may protect against Alzheimer disease (AD); however, clinical trials and other observational studies, including the Adult Changes in Thought (ACT) study, show no protection or promotion of AD. The objective of this study is to determine the relationship between common dementia-associated pathologies and mid- to late-life NSAID exposure.

METHODS

We examined the association of mid- to late-life NSAID use with neuropathologic findings on 257 autopsies from ACT, a population-based study of brain aging and incident dementia. Cumulative standard daily doses (SDD) of nonselective NSAIDs were determined from ≥10 years of computerized pharmacy dispensing data. Analyses were adjusted for selection bias to broaden generalizability of results to 3,026 eligible participants in the ACT cohort. Seven pathologic indices were evaluated: intermediate or frequent score for neuritic plaques, Braak stages V or VI for neurofibrillary tangles, >2 cerebral microinfarcts, the presence of any neocortical Lewy bodies, any macroscopic infarcts, any amyloid angiopathy, and moderate or severe atherosclerosis.

RESULTS

Of the neuropathologic indices evaluated, only neuritic plaque score was significantly increased in participants with greater use of nonselective NSAIDs (p = 0.065), specifically in those with high levels of cumulative use: 1,000-2,000 SDD (adjusted relative risk [RR] 2.16, 95% confidence interval [CI] 1.02-4.25, compared to light/nonuse [<60 SDD]) and >2,000 SDD (adjusted RR 2.37, 95% CI 1.24-4.67).

CONCLUSIONS

Increased neuritic plaque accumulation may explain the association between heavy use of nonselective NSAIDs and increased risk of dementia among ACT participants.