The association between Alzheimer's disease and thyroid disease in Rochester, Minnesota

Uncontrolled Thyroid during Pregnancy Alters the Circulative and Exerted Metabolome

Normal levels of thyroid hormones (THs) are essential for a normal pregnancy outcome, fetal growth and the normal function of the central nervous system. Hypothyroidism, a common endocrine disorder during pregnancy, is a significant metabolic factor leading to cognitive impairments. It is essential to investigate whether patients with thyroid dysfunction may present an altered circulative and excreted metabolic profile, even after receiving treatment with thyroxine supplements. NMR metabolomics was employed to analyze 90 serum and corresponding colostrum samples. Parallel analyses of the two biological specimens provided a snapshot of the maternal metabolism through the excretive and circulating characteristics of mothers. The metabolomics data were analyzed by performing multivariate statistical, biomarker and pathway analyses. Our results highlight the impact of hypothyroidism on metabolites’ composition during pregnancy and lactation. Thyroid disorder causing metabolite fluctuations may lead to impaired lipid and glucose metabolic pathways as well as aberrant prenatal neurodevelopment, thus posing a background for the occurrence of metabolic syndrome or neurogenerative diseases later in life. This risk applies to not only untreated but also hypothyroid women under replacement therapy since our findings in both biofluids framed a different metabolic phenotype for the latter group, thus emphasizing the need to monitor women adequately after treatment initiation.

The Association Between Thyroid Diseases and Alzheimer's Disease in a National Health Screening Cohort in Korea

Objectives

Thyroid dysfunction is linked to an increased risk of cognitive impairment. However, studies on the relationships between thyroid diseases and Alzheimer's disease (AD) have reported conflicting results. We investigated the associations between several thyroid diseases and AD in a nested case-control study.

Methods

A total of 1,977 participants with AD were identified by claims data from 2002-2015 among a random sample of half a million people in the Korean National Health Insurance database. We recruited 16,473 age- and sex-matched (1:4 ratio) control participants and applied conditional logistic regression to estimate the relationships between thyroid diseases and AD, with adjustments for potential confounders, such as basic demographics, lifestyle factors, and various medical conditions or comorbidities.

Results

The prevalence rates of hypothyroidism (odds ratio [OR]=1.14, 95% confidence interval [CI]=1.00-1.30), thyroiditis (OR=1.22, 95% CI=1.05-1.40), and hyperthyroidism (OR=1.13, 95% CI=1.01-1.28) were significantly higher in participants with AD than in control participants after adjustment for confounders.

Conclusion

In this large national sample, we found significant relationships between several thyroid diseases and AD. Despite of the need for further investigation, these findings could better support to appreciate the pathophysiology of AD.

Thyroid gland and brain: Enigma of Hashimoto's encephalopathy

The versatile clinical manifestations of the Hashimoto's chronic autoimmune thyroiditis often include psycho-neurological disorders. Although hypothyroidism disturbs significantly the ontogenesis and functions of central nervous system, causing in severe cases of myxedema profound impairment of cognitive abilities and even psychosis, the behavioral, motor and other psychoneurological disorders accompany euthyroid and slightly hypothyroid cases and periods of Hashimoto's disease as well, thus constituting the picture of so called "Hashimoto's encephalopathy". The entity, although discussed and explored for more than 50 years since its initial descriptions, remains an enigma of thyroidology and psychiatry, because its etiology and pathogenesis are obscure. The paper describes the development of current views on the role of thyroid in ontogeny and functions of brain, as well as classical and newest ideas on the etiology and pathogenesis of Hashimot's encephalopathy. The synopsis of the world case reports and research literature on this disorder is added with authors' own results obtained by study of 17 cases of Hashimoto's thyroiditis with schizophrenia-like clinical manifestations. The relation of the disease to adjuvant-like etiological factors is discussed. Three major mechanistic concepts of Hashimoto's encephalopathy are detailed, namely cerebral vasculitis theory, hormone dysregulation theory and concept, explaining the disease via direct action of the autoantibodies against various thyroid (thyroperoxidase, thyroglobulin, and TSH-receptor) and several extrathyroid antigens (alpha-enolase and other enzymes, gangliosides and MOG-protein, onconeuronal antigens) - all of them expressed in the brain. The article demonstrates that all above mentioned concepts intermingle and prone to unification, suggesting the unified scheme of pathogenesis for the Hashimoto's encephalopathy. The clinical manifestations, criteria, forms, course, treatment and prognosis of Hashimoto's encephalopathy and its comorbidity to other diseases - are also discussed in brief. The relation between Hashimoto's encephalopathy and non-vasculitis autoimmune encephalomyelitides of paraneoplastic and non-paraneoplastic origin is emphasized [1 figure, bibliography - 200 references].

Candidate SNP Markers of Familial and Sporadic Alzheimer's Diseases Are Predicted by a Significant Change in the Affinity of TATA-Binding Protein for Human Gene Promoters

While year after year, conditions, quality, and duration of human lives have been improving due to the progress in science, technology, education, and medicine, only eight diseases have been increasing in prevalence and shortening human lives because of premature deaths according to the retrospective official review on the state of US health, 1990-2010. These diseases are kidney cancer, chronic kidney diseases, liver cancer, diabetes, drug addiction, poisoning cases, consequences of falls, and Alzheimer's disease (AD) as one of the leading pathologies. There are familial AD of hereditary nature (~4% of cases) and sporadic AD of unclear etiology (remaining ~96% of cases; i.e., non-familial AD). Therefore, sporadic AD is no longer a purely medical problem, but rather a social challenge when someone asks oneself: “What can I do in my own adulthood to reduce the risk of sporadic AD at my old age to save the years of my lifespan from the destruction caused by it?” Here, we combine two computational approaches for regulatory SNPs: Web service SNP_TATA_Comparator for sequence analysis and a PubMed-based keyword search for articles on the biochemical markers of diseases. Our purpose was to try to find answers to the question: “What can be done in adulthood to reduce the risk of sporadic AD in old age to prevent the lifespan reduction caused by it?” As a result, we found 89 candidate SNP markers of familial and sporadic AD (e.g., rs562962093 is associated with sporadic AD in the elderly as a complication of stroke in adulthood, where natural marine diets can reduce risks of both diseases in case of the minor allele of this SNP). In addition, rs768454929, and rs761695685 correlate with sporadic AD as a comorbidity of short stature, where maximizing stature in childhood and adolescence as an integral indicator of health can minimize (or even eliminate) the risk of sporadic AD in the elderly. After validation by clinical protocols, these candidate SNP markers may become interesting to the general population [may help to choose a lifestyle (in childhood, adolescence, and adulthood) that can reduce the risks of sporadic AD, its comorbidities, and complications in the elderly].

Correlation of thyroid dysfunction and cognitive impairments induced by subcortical ischemic vascular disease

BACKGROUND

To date, the relationship between thyroid dysfunction and subcortical ischemic vascular disease (SIVD)-induced cognitive impairments still remains elusive.

METHODS

Cognitive performances were examined in 215 participants, including 54 healthy participants, 52 SIVD patients with no dementia (SIVDND), 55 patients with mild cognitive impairment (SVMCI), and 54 patients with vascular dementia (VD). Serum thyroid-stimulating hormone (TSH), total triiodothyronine (TT3), free triiodothyronine (FT3), total thyroxine (TT4) and free thyroxine (FT4), thyroglobulin antibody (TGA), and antithyroid peroxidase antibody (TPO-Abs) were quantified by radioimmunoassay or ELISA.

RESULTS

A close correlation between thyroid status and cognitive dysfunction in SIVD was observed. Serum TT3 and FT3 levels decreased, whereas serum TSH level increased, with the decline in cognitive functions. Furthermore, TT3 levels showed a positive correlation, whereas TSH level showed a negative correlation, with the Mini-Mental State Examination (MMSE) scores. Our results suggested that thyroid function was associated with cognitive impairments induced by SIVD. Also, thyroid function and thyroid hormone level could be a risk factor in the development of SIVD. Serum TT3 and TSH levels might also be used as biomarkers for cognitive dysfunction.

CONCLUSIONS

These findings might contribute to a more accurate clinical diagnosis and differentiation among normal controls, SIVDND, SVMCI, and VD patients, in order to develop appropriate intervention approaches for SIVD therapeutic treatment.

The role of thyroid hormones as inductors of oxidative stress and neurodegeneration

Reactive oxygen species (ROS) are oxidizing agents amply implicated in tissue damage. ROS production is inevitably linked to ATP synthesis in most cells, and the rate of production is related to the rate of cell respiration. Multiple antioxidant mechanisms limit ROS dispersion and interaction with cell components, but, when the balance between ROS production and scavenging is lost, oxidative damage develops. Many traits of aging are related to oxidative damage by ROS, including neurodegenerative diseases. Thyroid hormones (THs) are a major factor controlling metabolic and respiratory rates in virtually all cell types in mammals. The general metabolic effect of THs is a relative acceleration of the basal metabolism that includes an increase of the rate of both catabolic and anabolic reactions. THs are related to oxidative stress not only by their stimulation of metabolism but also by their effects on antioxidant mechanisms. Thyroid dysfunction increases with age, so changes in THs levels in the elderly could be a factor affecting the development of neurodegenerative diseases. However, the relationship is not always clear. In this review, we analyze the participation of thyroid hormones on ROS production and oxidative stress, and the way the changes in thyroid status in aging are involved in neurodegenerative diseases.

A cross-sectional study on thyroid status in North Indian elderly outpatients with dementia

BACKGROUND

Several population based studies have demonstrated an association between hypo-or hyperthyroidism and dementia in last two decades. As a consequence, thyroid stimulating hormone has become part of the screening laboratory test for dementia.

AIM

The aim of the present study was to evaluate the association between thyroid function and Alzheimer's disease (AD) and vascular dementia (VaD) and to determine the risk of AD and VaD in clinically euthyroid patients.

MATERIALS AND METHODS

A cross-sectional hospital based study was carried out in subjects diagnosed with AD/VaD and were assessed for thyroid status as routine screening test.

RESULTS

Free T3, free T4 and TSH were studied in 114 AD patients (mean age: 65 years), 35 VaD patients (mean age: 62 years) and 105 control subjects (mean age: 62 years). In AD group, TSH levels were significantly lower than controls (P = 0.00) and for each unit increase in TSH level, the odds of having dementia decreased by 37.1%. No such relation was seen in VaD.

CONCLUSION

The results suggest a consistent association of subclinical hyperthyroidism and AD.

Thyroid medication use and subsequent development of dementia of the Alzheimer type

Associations between medication use and the development of Alzheimer disease have been investigated since the late 1900s. Thyroid hormone supplementation is rarely a studied medication class in this area of research. We examined data from participants enrolled in longitudinal studies at the Washington University Alzheimer's Disease Research Center for associations between thyroid disease, thyroid hormone supplementation therapy, and subsequent development of dementia of the Alzheimer type (DAT). Data collected between April 1992 and June 2008 from 499 participants, 184 men and 315 women, were analyzed. Mean age was 76.9 years (SD = 9.2). At baseline, 61 participants reported thyroid medication use and 87 were identified as having a history of thyroid dysfunction. These participants progressed to a DAT diagnosis more rapidly than individuals not taking thyroid medication (hazard ratios [HR]: 1.67, 95% CI: 0.99-2.78, P = .054). Although an interesting trend was seen, baseline thyroid disease was not significantly (P = .093) associated with time to DAT diagnosis. Our findings suggest that utilization of thyroid medication may be associated with the development of DAT.

The thyroid-brain interaction in thyroid disorders and mood disorders

Thyroid hormones play a critical role in the metabolic activity of the adult brain, and neuropsychiatric manifestations of thyroid disease have long been recognised. However, it is only recently that methodology such as functional neuroimaging has been available to facilitate investigation of thyroid hormone metabolism. Although the role of thyroid hormones in the adult brain is not yet specified, it is clear that without optimal thyroid function, mood disturbance, cognitive impairment and other psychiatric symptoms can emerge. Additionally, laboratory measurements of peripheral thyroid function may not adequately characterise central thyroid metabolism. Here, we review the relationship between thyroid hormone and neuropsychiatric symptoms in patients with primary thyroid disease and primary mood disorders.

Thyroid function, the risk of dementia and neuropathologic changes: the Honolulu-Asia aging study

Thyroid dysfunction is associated with cognitive impairment and dementia, including Alzheimer's disease (AD). It remains unclear whether thyroid dysfunction results from, or contributes to, Alzheimer pathology. We determined whether thyroid function is associated with dementia, specifically AD, and Alzheimer-type neuropathology in a prospective population-based cohort of Japanese-American men. Thyrotropin, total and free thyroxine were available in 665 men aged 71-93 years and dementia-free at baseline (1991), including 143 men who participated in an autopsy sub-study. During a mean follow-up of 4.7 (S.D.: 1.8) years, 106 men developed dementia of whom 74 had AD. Higher total and free thyroxine levels were associated with an increased risk of dementia and AD (age and sex adjusted hazard ratio (95% confidence interval) per S.D. increase in free thyroxine: 1.21 (1.04; 1.40) and 1.31 (1.14; 1.51), respectively). In the autopsied sub-sample, higher total thyroxine was associated with higher number of neocortical neuritic plaques and neurofibrillary tangles. No associations were found for thyrotropin. Our findings suggest that higher thyroxine levels are present with Alzheimer clinical disease and neuropathology.

Thyroid hormone regulates endogenous amyloid-beta precursor protein gene expression and processing in both in vitro and in vivo models

Thyroid hormone negatively regulates the amyloid-beta precursor protein (APP) gene in thyroid hormone receptor (TR)-transfected neuroblastoma cells. A negative thyroid hormone response element (nTRE) that mediates this regulation has been identified in the first exon of the APP gene. We demonstrate in an in vivo system that expression of APP mRNA, APP protein, and APP secretase cleavage products in mouse brain is influenced by thyroid status. Adult female mice were made hyperthyroid or hypothyroid for 3 weeks and compared to euthyroid mice. APP gene product expression was increased in hypothyroid mouse brain and reduced in hyperthyroid mouse brain, when compared to euthyroid controls. We observed similar effects of thyroid hormone on endogenous APP gene expression in human neuroblastoma cells. The incidence of hypothyroidism increases with age, and localized hypothyroidism of central nervous system has been reported in some patients with Alzheimer's disease (AD). Reduced action of thyroid hormone on the APP gene may contribute to AD pathology by increasing APP expression and the levels of processed APP products. These findings may be an underlying mechanism contributing to the association of hypothyroidism with AD in the elderly, as well as identifying a potential therapeutic target. Pharmacologic supplementation of thyroid hormone, or its analogs, may reduce APP gene expression and beta amyloid peptide accumulation.

Thyroid Function in Patients With Alzheimer Disease: Implications on Response to Anticholinesterase Treatment

Increasing evidence supports an extensive interrelationship between thyroid hormones and the cholinergic system, which is selectively and early affected in Alzheimer disease (AD). The aim of the present study was to explore thyroid function in patients with AD before and after acetylcholinesterase inhibition treatment to possibly identify variances in response. Thyroid function tests were evaluated in 28 AD patients and 24 age and sex-matched controls. Nineteen of the patients were reevaluated after (4 mo) treatment with donepezil. Serum thyrotropin (TSH), triiodothyronine (T3), thyroxine (T4), the free fractions (fT3, fT4) and thyroid autoantibodies were determined using standard methods. All subjects were clinically euthyroid. Patients presented with higher fT4 and anti-thyroperoxidase levels, as compared with the controls. Significant reduction in T4, fT3, fT4, and anti-thyroperoxidase levels were observed 4 months after treatment. Responders had higher T4 and fT4, than nonresponders, followed by significant reductions after treatment. The above, within the normal range alterations, may represent a direct effect on hormone release from the thyroid gland and/or increased conversion of T4 to T3 within the brain. Higher T4 and fT4 levels before treatment might predict a favorable response to donepezil treatment.

Thyroid hormones, dementia, and atrophy of the medial temporal lobe

CONTEXT

Thyroid function has been related to Alzheimer disease (AD), but it remains unclear whether thyroid dysfunction results from or contributes to developing AD.

OBJECTIVE

The objective of the study was to determine the association between thyroid function and both medial temporal lobe atrophy on brain magnetic resonance imaging (MRI) as putative early sign of AD and risk of dementia.

DESIGN AND PARTICIPANTS

This was a population-based cohort study among 1077 elderly subjects aged 60-90 yr and dementia free at baseline (1995-1996).

MAIN OUTCOME MEASURES

Nonfasting serum levels of TSH, free T(4) (fT(4)), T(3), and rT(3) were available in 1025 subjects followed up for incident dementia until 2005. In a subset of 489 nondemented elderly, we assessed volumes of the hippocampus and amygdala on brain MRI. Subjects using thyroid medication were excluded.

RESULTS

During 5657 person-years of follow-up (mean 5.5 yr), 63 subjects were diagnosed with dementia (46 with AD). TSH and thyroid hormones were not associated with risk of dementia or AD. TSH and T(3) were also not related to brain atrophy, whereas nondemented subjects with higher fT(4) levels had more hippocampal and amygdalar atrophy on MRI. Similar associations were found for rT(3). Excluding subjects with thyroid disorders or incipient AD did not change the results.

CONCLUSION

In our study, TSH was related neither to risk of AD nor with early MRI markers thereof, arguing against an important role of thyroid function in the development of AD. Whether the association of higher fT(4) and rT(3) levels with brain atrophy on MRI has functional significance remains to be elucidated.

Barriers to remember: brain-targeting chemical delivery systems and Alzheimer's disease

Brain-targeted chemical delivery systems (CDSs) represent rational drug design attempts not only to deliver but also to target drugs to their site of action. Using a sequential metabolism approach, the special bidirectional properties of the blood-brain barrier can be exploited to smuggle the precursors of therapeutic compounds across the barrier and lock them inside the brain ready for sustained release of the active drugs. Many potential therapeutic applications can be envisioned for such CDSs; here, the potential of brain-targeted estradiol for the prevention and treatment of Alzheimer's disease is reviewed in detail.

Hyperthyroid dementia: clinicoradiological findings and response to treatment

Dementia associated with hyperthyroidism is less well documented than is hypothyroid dementia. Therapeutic response of hyperthyroid dementia and associated cerebral circulatory and/or metabolic abnormalities has not been elucidated. We described a patient with hyperthyroid dementia and clinicoradiological response to treatment. Single photon emission computed tomographic (SPECT) study was repeated and analyzed semiquantitatively. A 67-year-old man experienced progressive impairments of attention, memory, constructive skills and behavior as well as hand tremor and weight loss of two-year duration. Laboratory findings were compatible with Graves' disease. The initial SPECT showed diffuse tracer uptake defect with an accentuation in the bilateral temporoparietal regions. Clinical and SPECT findings both suggested concurrent "possible" Alzheimer's disease. However, initial treatment with a beta-blocker improved behavior and attention-related cognitive functions as well as tracer uptake in the frontal lobes. Subsequent treatment with additional methimazole then improved memory and constructive abilities when a euthyroid state was established. Uptake defect in the temporoparietal regions also responded gradually to the medication. We suggest that the present patient represent hyperthyroid dementia, which responds favorably to treatment with regard to clinical symptoms and SPECT findings. We also suggest that thyroid function be measured in patients with "possible" Alzheimer's disease because treatable hyperthyroid dementia may not be identified.

Subclinical hyperthyroidism and the risk of dementia. The Rotterdam study

AIMS AND SUBJECTS: We investigated the prospective relationship between thyroid status and the risk of dementia and Alzheimer's disease among a random sample of 1843 participants, aged 55 years and over, from the population-based prospective Rotterdam Study.

METHODS

Thyroid status was measured at baseline (1990-93), through assessment of serum antibodies to thyroid peroxidase (TPO-Abs, positive: >10 IU/ml), serum TSH levels, and when TSH was abnormal (<0.4 or >4.0 mU/l), serum thyroxin levels (T4). At baseline and at follow up, after on average 2 years, participants were screened for dementia. Diagnoses were based on international criteria.

RESULTS

Persons with reduced TSH levels at baseline had a more than threefold increased risk of dementia (RR = 3.5, 95%CI: 1.2-10.0) and of Alzheimer's disease (RR = 3.5, 95%CI: 1.1-11.5), after adjustment for age and sex. Among persons with reduced TSH levels, T4 levels appeared to be positively related to the risk of dementia (RR per SD increase = 2.9, 95%CI: 0.7-12.2), although none of those who became demented had a T4 level above the normal range (>140 nmol/l). The risk of dementia was especially increased in subjects with low TSH who were positive for TPO-Abs (RR = 23.7, 95%CI: 4.0-140).

CONCLUSIONS

This is the first prospective study to suggest that subclinical hyperthyroidism in the elderly increases the risk of dementia and Alzheimer's disease.

Thyroid autoimmunity and aging

Aging is associated with the appearance of several serum autoantibodies, including thyroid autoantibodies. The biological and clinical significance of this phenomenon is still unknown, because, with the exception of primary myxedema, the prevalence of clinically overt thyroid autoimmune diseases is not increased in the elderly. The peculiar link between autoimmune thyroid failure and aging is also underscored by the high prevalence of subclinical hypothyroidism in elderly subjects with positive serum thyroid autoantibodies, and could be the consequence of preferential age-dependent expression of destructive effector mechanisms and/or increased target gland susceptibility. Thyroid autoimmunity and subclinical hypothyroidism have been also implicated in the pathogenesis of other age-associated disorders, in particular coronary heart disease. Interestingly, recent data from our laboratories showed that thyroid autoantibodies are rare in healthy centenarians and in other highly selected aged populations, while they are frequently observed in unselected or hospitalized elderly. Taken together, these data suggest that thyroid autoimmune phenomena are not the consequence of the aging process itself, but rather might be related to age-associated disease.

Association between dementia and elevated TSH: a community-based study

We report on 194 individuals (96 men and 98 women), aged 65 and over, who had dementia assessments and basal TSH measurements as part of an ongoing epidemiological study of dementing disorders in a larger population. Dementia was diagnosed according to DSM-III-R and measured by the Clinical Dementia Rating scale; CDR scores of 0, 0.5, and > or = 1, represent individuals with no dementia (n = 122), possible dementia (n = 29), and definite dementia (n = 43), respectively. The odds ratio for the association of elevated TSH with definite dementia (CDR > or = 1) was 3.8 (95% confidence interval = 1.6, 9.1) and with possible and/or definite dementia (CDR > or = 0.5) was 3.8 (95% confidence interval = 1.6, 9.2), after adjusting for the effects of age, gender, and level of education. This is the first community-based study to report an association between TSH elevation and dementia. Our findings are consistent with recent evidence that subclinical hypothyroidism is associated with cognitive impairment, and that thyroidal state may influence cerebral metabolism.

Prevalence of thyroid hormone abnormalities in elderly patients with symptoms of organic brain disease

Analysis of the serum concentrations of free thyroid hormones (fT3, fT4) and thyrotropin (TSH) in 173 psychogeriatric patients (94 females and 79 males, mean age 79 +/- 8 years) disclosed that the hormone levels were related to sex, psychiatric diagnosis, medication and the presence of nonthyroid illness (NTI). Subnormal concentrations of thyroid hormones and/or TSH were found in 25% of the patients. In addition, fT3 and fT4 concentrations were significantly lower (p < 0.05 and p < 0.001, respectively) in demented males compared with demented females although the levels were within the reference limits. Strongly negative correlations between fT3 and age (p < 0.001), and between fT3 and the sedimentation rate (SR) (p < 0.01) were found in demented but not in non-demented patients. These correlations were most pronounced in (age) or restricted to (SR) demented males. In addition, the correlation between fT3 and Hb was strongly positive (p < 0.001) in demented as well as in nondemented patients, particularly in males. The concentration of fT4 was positively correlated to Hb in demented males (p < 0.001), whereas TSH concentration was positively correlated to Hb in demented females (p < 0.05). The results show that TSH is not sufficient as the sole screening assay for evaluation of possible thyroid dysfunction in psychogeriatric patients. In addition, central (hypothalamic?) hypothyroidism may be present in a substantial amount of psychogeriatric patients, as we found an adequate TSH response to exogenous thyrotropin-releasing hormone (TRH) also in patients with decreased fT3/fT4 and no signs of non thyroid diseases. Furthermore, there was an apparent lack of correlation between thyroid hormone levels and dementia (or subgroups of dementia), even though thyroid hormone abnormalities seemed to be rather common in frontotemporal dementia (38%) and non specified dementia (36%).

Epidemiology of dementia in Rochester, Minnesota

OBJECTIVE

To present the results of several retrospective epidemiologic studies of dementia in Rochester, Minnesota.

MATERIAL AND METHODS

These studies were done by using the medical records-linkage resources of the Rochester Epidemiology Project.

RESULTS

The incidence and prevalence of dementia increase sharply with advancing age. No difference is noted in overall age-adjusted incidence rates by gender. Rochester studies provide the only 25-year time trend analyses of the incidence of dementia in the United States. Time trends over three prevalence dates indicate an increase in prevalence in this community. Survival is decreased among patients with dementing illness. Case-control studies of Alzheimer's disease (AD) show that general medical conditions, previous head injury, thyroid disease, exposure to therapeutic radiation, anesthesia, and blood transfusion are generally not risk factors for AD. Patients with depression may have an increased risk for the development of AD. Sociodemographic factors such as education, occupation, marital status, and type of dwelling were not significantly different among patients with AD and their age-and gender-matched control subjects.

CONCLUSION

The Rochester Epidemiology Project has proved to be an excellent resource for the study of the incidence, prevalence, and risk factors for dementia.

Risk factors for late-onset Alzheimer's disease: a population-based, case-control study

Our current knowledge of risk factors for Alzheimer's disease is limited and primarily addresses early-onset disease. This study aimed to determine the risk factors for late-onset Alzheimer's disease using a case-control approach. Ninety-eight cases and 216 controls were gathered from an ongoing population survey on aging and dementia in Stockholm (the Kungsholmen Project). We found a high relative risk (3.2; 95% confidence interval, 1.8-5.7) with the presence of at least one first-degree relative affected by dementia. Among all the other risk factors, alcohol abuse (relative risk, 4.4; 95% confidence interval, 1.4-13.8) and manual work (relative risk for men of 5.3; 95% confidence interval, 1.1-25.5) emerged as positively associated. No clear association was found with a family history of Parkinson disease, advanced parental age at index delivery, season of birth, or previous head trauma. In conclusion, our data suggest that the main risk factor for late-onset Alzheimer's disease is a family history of dementia, as has been previously reported for early-onset disease. Moreover, alcohol abuse and occupational exposure might play a specific role for this form of the disease.