Alzheimer Disease: Zandi P

Sjögren M, Mielke M, Gustafson D, Zandi P, Skoog I. · Department of Experimental Geriatrics, Neurotec, Karolinska Institute, Huddinge, Sweden. · Mech Ageing Dev. · Pubmed #16332384 No free full text.

Abstract: The predominating theory on the pathophysiology of Alzheimer's disease (AD) concerns the mis-metabolism of amyloid precursor protein (APP). As a result of this mis-metabolism, there is an increased production of the 42 amino acid form of beta-amyloid (Abeta42) that rapidly will form oligomers that initiates a cascade of events leading to the accumulation of amyloid plaques. Commonly recognised as vascular factors, hypertension, hypercholesterolemia and diabetes and the inheritance of the epsilon4 allele of the APOE gene, are also risk factors for AD. These risks have been found to promote the production of Abeta42. An association between cholesterol and the development of AD was suggested in the early 1990s and ever since, an increasing amount of research has confirmed that there is a link between cholesterol and the development of AD. A high cholesterol levels in mid-life is a risk for AD and statins, i.e., cholesterol-lowering drugs, reduce this risk. Statins may not only inhibit enzymes involved in the endogenous synthesis of cholesterol but also affect enzymes involved in Abeta metabolism, i.e., alpha-secretase and beta-secretase. This normalises the breakdown of APP thereby promoting the non-amyloidogenic pathway. In this review, investigations focusing on cholesterol and Alzheimer's disease are presented.

Steinberg M, Corcoran C, Tschanz JT, Huber C, Welsh-Bohmer K, Norton MC, Zandi P, Breitner JC, Steffens DC, Lyketsos CG. · Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. · Int J Geriatr Psychiatry. · Pubmed #16955439 No free full text.

Abstract: OBJECTIVE: To investigate the probability of individual neuropsychiatric symptoms in dementia patients as a function of eight risk factors. METHODS: In the Cache County Study, we administered the Neuropsychiatric Inventory (NPI) to 328 dementia patients at baseline. Approximately 18 months later, we re-administered the NPI to 184 participants available for follow-up. Generalized estimating equation methods were used to model the probability of individual neuropsychiatric symptoms as a function of: gender, age, education, dementia type and severity, APOE status, time of observation, and general medical health. RESULTS: Women showed increased tendency toward anxiety, [odds ratio (OR) 2.22, 95% confidence interval (CI) 1.31-3.76] and delusions (OR 2.15, CI 1.22-3.78), but older persons of both sexes showed less tendency toward anxiety. Dementia severity increased the tendency toward hallucinations and agitation (OR 2.42, CI 1.81-3.23) and decreased risk of depression. Positive APOE epsilon4 status increased the tendency toward aberrant motor behavior (OR 1.84, CI 1.05-3.22). Among dementia diagnoses, those with Alzheimer's disease showed decreased tendency toward agitation (OR 0.58, CI 0.35-0.95), depression (OR 0.56, CI 0.33-0.96) and disinhibition (OR 0.46, CI 0.24-0.88). Later time of observation increased risk of aberrant motor behavior and delusions, and more serious medical comorbidity increased risk of, agitation, irritability, disinhibition, and aberrant motor behavior. CONCLUSIONS: Gender, age, dementia severity, APOE epsilon4, dementia diagnosis, time of observation, and general medical health appear to influence the occurrence of individual neuropsychiatric symptoms.

Avramopoulos D, Zandi P, Gherman A, Fallin MD, Bassett SS. · Department of Psychiatry, The Johns Hopkins University, School of Medicine, Broadway Research Building 509, 733 North Broadway, Baltimore, MD 21205, USA. · Hum Genomics. · Pubmed #16848972 No free full text.

Abstract: Genes for complex disorders have proven hard to find using linkage analysis. The results rarely reach the desired level of significance and researchers often have failed to replicate positive findings. There is, however, a wealth of information from other scientific approaches which enables the formation of hypotheses on groups of genes or genomic regions likely to be enriched in disease loci. Examples include genes belonging to specific pathways or producing proteins interacting with known risk factors, genes that show altered expression levels in patients or even the group of top scoring locations in a linkage study. We show here that this hypothesis of enrichment for disease loci can be tested using genome-wide linkage data, provided that these data are independent from the data used to generate the hypothesis. Our method is based on the fact that non-parametric linkage analyses are expected to show increased scores at each one of the disease loci, although this increase might not rise above the noise of stochastic variation. By using a summary statistic and calculating its empirical significance, we show that enrichment hypotheses can be tested with power higher than the power of the linkage scan data to identify individual loci. Via simulated linkage scans for a number of different models, we gain insight in the interpretation of genome scan results and test the power of our proposed method. We present an application of the method to real data from a late-onset Alzheimer's disease linkage scan as a proof of principle.

Lyketsos CG, Toone L, Tschanz J, Rabins PV, Steinberg M, Onyike CU, Corcoran C, Norton M, Zandi P, Breitner JC, Welsh-Bohmer K, Anthony J, Østbye T, Bigler E, Pieper C, Burke J, Plassman B, Green RC, Steffens DC, Klein L, Leslie C, Townsend JJ, Wyse BW, Munger R, Williams M, Anonymous00077. · Division of Geriatric Psychiatry and Neuropsychiatry, Dept. of Psychiatry and Behavioral Sciences, School of Medicine, The Johns Hopkins University, Johns Hopkins Hospital, Baltimore, MD 21287, USA. · Am J Geriatr Psychiatry. · Pubmed #16085781 No free full text.

Abstract: OBJECTIVE: Authors investigated medical comorbidity in persons with dementia and "Cognitive Impairment, No Dementia" (CIND). METHODS: The Cache County Study is an ongoing population-based study of the epidemiology of dementia, the risk factors for conversion from CIND to dementia, and the progression of dementia. As part of the study's first incidence wave, persons with dementia (N=149), CIND (N=225), or without cognitive impairment (N=321) were identified and studied. Participants received comprehensive clinical evaluations and were rated on the General Medical Health Rating (GMHR), a global measure of seriousness of medical comorbidity. Participants and informants also completed the Mini-Mental State Exam and provided self-report information about comorbid medical conditions and functioning in activities of daily living. RESULTS: There were few differences in number or type of comorbid medical conditions between persons with CIND and dementia, but persons with dementia were prescribed more medications. Stroke was more common in dementia participants, but other illnesses common in old age were not significantly different across cognitive groups. Medical comorbidity was more serious in both dementia and CIND, such that both groups were less likely to have "little to no" comorbidity. Seriousness of medical comorbidity was significantly associated with worse day-to-day functioning and cognition. CONCLUSIONS: Persons with CIND and dementia have more serious medical comorbidity than comparable persons without cognitive impairment. This comorbidity may play a role in the progression of CIND and dementia. Future studies should investigate the role of medical comorbidity and its treatment on dementia onset or progression, as well as the mechanisms mediating its neuropathologic effects.

Tschanz JT, Corcoran C, Skoog I, Khachaturian AS, Herrick J, Hayden KM, Welsh-Bohmer KA, Calvert T, Norton MC, Zandi P, Breitner JC, Anonymous00121. · Center for Epidemiologic Studies, Department of Psychology, Utah State University, Logan 84322-4440, USA. · Neurology. · Pubmed #15079016 No free full text.

Abstract: OBJECTIVE: To examine the relative risk and population attributable risk (PAR) of death with dementia of varying type and severity and other risk factors in a population of exceptional longevity. METHODS: Deaths were monitored over 5 years using vital statistics records and newspaper obituaries in 355 individuals with prevalent dementia and 4,328 without in Cache County, UT. Mean age was 83.3 (SD 7.0) years with dementia and 73.7 (SD 6.8) years without. History of coronary artery disease, hypertension, diabetes, and other life-shortening illness was ascertained from interviews. RESULTS: Death certificates implicated dementia as an important cause of death, but other data suggested a stronger association. Adjusted Cox relative hazard and PAR of death were higher with dementia than with any other illness studied. Relative hazard of death with dementia was highest at ages 65 to 74, but the high prevalence of dementia after age 85 resulted in 27% PAR among the oldest old. Mortality increased substantially with severity of dementia. Alzheimer disease shortened survival time most dramatically in younger participants, but vascular dementia posed a greater mortality risk among the oldest old. CONCLUSION: In this population, dementia was the strongest predictor of mortality, with a risk two to three times those of other life-shortening illnesses.