Biomedical subjects

Ming-Xin Tang

Publications and source records attributed to Ming-Xin Tang.

At least 19 recordsLinked to original sources

PubMed2007

Relation of higher folate intake to lower risk of Alzheimer disease in the elderly.

BACKGROUND: Higher intake of folate and vitamins B6 (pyridoxine hydrochloride) and B12 (cyanocobalamin) may decrease the risk of Alzheimer disease (AD) through the lowering of homocysteine levels. OBJECTIVE: To relate intake of folate and vitamins B6 and B12 to AD risk. DESIGN AND PATIENTS: We followed up 965 persons 65 years or older without dementia at baseline for a mean +/- SD period of 6.1 +/- 3.3 person-years after the administration of a semiquantitative food frequency questionnaire. Total, dietary, and supplement intake of folate and vitamins B6 and B12 and kilocalorie intake were estimated from the questionnaire responses. We related energy-adjusted intake of folate and vitamins B6 and B12 to incident AD using the Cox proportional hazards regression model. MAIN OUTCOME MEASURE: Incident AD. RESULTS: We found 192 cases of incident AD. The highest quartile of total folate intake was related to a lower risk of AD (hazard ratio, 0.5; 95% confidence interval, 0.3-0.9; P=.02 for trend) after adjustment for age, sex, education, ethnic group, the epsilon4 allele of apolipoprotein E, diabetes mellitus, hypertension, current smoking, heart disease, stroke, and vitamin B6 and B12 levels. Vitamin B6 and B12 levels were not related to the risk of AD. CONCLUSIONS: Higher folate intake may decrease the risk of AD independent of other risk factors and levels of vitamins B6 and B12. These results require confirmation with clinical trials.

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PubMed2006

Relation of plasma homocysteine to plasma amyloid beta levels.

BACKGROUND: Elevated plasma homocysteine and amyloid beta (Abeta) have been associated with Alzheimer's disease (AD). We investigated the cross-sectional association between these biomarkers. METHODS: We used linear regression to relate plasma homocysteine and Abeta adjusting for age, gender, creatinine, APOE-epsilon4, and ethnic group in 327 persons aged 78 +/- 6.6 years. RESULTS: Plasma homocysteine correlated with age, serum creatinine, plasma Abeta40 and Abeta42, and was inversely correlated with serum vitamin B12, and folate. Abeta42, but not Abeta40, was related to later development of dementia. Homocysteine was related to higher Abeta40 levels (coefficient = 2.0; P < 0.0001) and this association was attenuated after adjustment for creatinine (coefficient = 1.0; P < 0.0001). The crude association between homocysteine and Abeta42 was weaker (coefficient = 0.5; P = 0.01) and became non-significant after adjustment for creatinine (coefficient = 0.4; P = 0.06). These associations were unrelated to ethnicity, the presence of APOE-epsilon4 or dementia. Analyses by quartiles of homocysteine showed that these association were driven primarily by the fourth quartile. CONCLUSIONS: Plasma homocysteine is directly related to Abeta40. The association with Abeta42 is not significant. These results seem to indicate that homocysteine is related to aging but not specifically to AD.

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PubMed2006

The progression of cognition, psychiatric symptoms, and functional abilities in dementia with Lewy bodies and Alzheimer disease.

BACKGROUND: Although dementia with Lewy bodies (DLB) may be one of most common forms of dementia, relatively little is known about its cognitive and functional course. OBJECTIVE: To compare change over time in general cognitive status, memory test performance, psychiatric symptoms, neurological signs, and functional abilities in patients with probable DLB and probable Alzheimer disease (AD). DESIGN: Twenty-eight patients who met diagnostic criteria for DLB were recruited into the study from 3 sites. Patients with AD (n = 55) were selected from a larger cohort and matched 2 to 1 to the patients with DLB on age and baseline global cognitive status. Patients were followed up at 6-month intervals for an average of 6.2 visits and assessed at each visit with tests of global cognitive functioning and verbal learning and memory and measures of psychiatric, neurological, and functional status. RESULTS: At the baseline evaluation, patients with DLB performed more poorly on a measure of constructional praxis and all measures of functional status. They also had more severe psychiatric symptoms and neurological signs than the AD group. Despite these initial differences, generalized estimating equations applied to regression analyses with repeated measures determined that the only difference between the 2 groups in change in cognitive test performance was on a measure of recognition memory; patients with AD declined, while patients with DLB remained relatively stable. Patients with DLB had relatively stable behavioral symptoms and visual illusions, whereas patients with AD had a significant increase in these symptoms over time. Neurological and functional changes over time were similar in the 2 groups. CONCLUSIONS: Both baseline and longitudinal differences between patients with DLB and patients with AD were noted; these have implications for clinical diagnosis and treatment.

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PubMed2006

Apolipoprotein E epsilon4 and age at onset of sporadic and familial Alzheimer disease in Caribbean Hispanics.

BACKGROUND: The primary effect of the apolipoprotein E epsilon4 (APOE epsilon4) allele is on the age at onset of Alzheimer disease (AD). OBJECTIVE: To investigate whether the presence of the APOE epsilon4 allele can account for the earlier age at onset of familial AD (FAD) compared with sporadic AD (SAD). DESIGN: Population-based, case series ascertained in a prospective study of aging and dementia in Medicare recipients aged 65 years or older. SETTING: Clinics in northern Manhattan and in the Dominican Republic and Puerto Rico. PARTICIPANTS: There were 680 Caribbean Hispanic subjects: 111 patients with FAD, with at least 1 family member with dementia; 163 patients with SAD; and 406 elderly persons without dementia or other illnesses. Main Outcome Measure Age at onset of dementia was examined in relation to frequency of APOE epsilon4. Sex, education, and medical risk factors for stroke, hypertension, diabetes, and heart disease were examined as effect modifiers. RESULTS: The mean age at onset of AD was significantly lower in FAD than in SAD, and a statistically significant dose effect of the APOE epsilon4 allele was present for age at onset in FAD (P = .001) but not in SAD. The age at onset in patients homozygous for the APOE epsilon4 allele with FAD and SAD was similar. Compared with SAD, the major difference was younger age at onset in patients with FAD who were heterozygous for the APOE epsilon4 allele and those without an APOE epsilon4 allele. CONCLUSIONS: Apolipoprotein E epsilon4 had a consistent lowering effect on age at onset of FAD, but this was attenuated in SAD. This suggests that among individuals with a family history of AD and the APOE epsilon4 allele, additional genetic or environmental factors may accelerate the onset of dementia.

Age of Onset↗

PubMed2006

Stroke and memory performance in elderly persons without dementia.

BACKGROUND: There are conflicting data showing that stroke is associated with a higher risk of dementia and a more severe decline in persons with cognitive impairment. However, it remains unclear if cerebrovascular disease is directly related to cognitive decline in the absence of cognitive impairment or dementia. OBJECTIVE: To examine the association between stroke and changes in cognitive function over time in elderly persons without dementia at baseline. DESIGN: The results of neuropsychological tests from several intervals over a 5-year period were clustered into domains of memory, abstract/visuospatial, and language in 1271 elderly persons without dementia or cognitive decline. Stroke was related to the slope of performance in each cognitive domain using generalized estimating equations. RESULTS: Memory performance declined over time, while abstract/visuospatial and language performance remained stable during the study period. Stroke was associated with a more rapid decline in memory performance, while there was no association between stroke and decline in abstract/visuospatial or language performance. The association between stroke and decline in memory performance was strongest for men and for persons without an APOEepsilon4 allele. A significant association between stroke and decline in abstract/visuospatial performance was also observed for persons without the APOEepsilon4 allele. CONCLUSION: A history of stroke is related to a progressive decline in memory and abstract/visuospatial performance, especially among men and those without an APOEepsilon4 allele.

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PubMed2006

Mediterranean diet and risk for Alzheimer's disease.

OBJECTIVE: Previous research in Alzheimer's disease (AD) has focused on individual dietary components. There is converging evidence that composite dietary patterns such as the Mediterranean diet (MeDi) is related to lower risk for cardiovascular disease, several forms of cancer, and overall mortality. We sought to investigate the association between MeDi and risk for AD. METHODS: A total of 2,258 community-based nondemented individuals in New York were prospectively evaluated every 1.5 years. Adherence to the MeDi (zero- to nine-point scale with higher scores indicating higher adherence) was the main predictor in models that were adjusted for cohort, age, sex, ethnicity, education, apolipoprotein E genotype, caloric intake, smoking, medical comorbidity index, and body mass index. RESULTS: There were 262 incident AD cases during the course of 4 (+/-3.0; range, 0.2-13.9) years of follow-up. Higher adherence to the MeDi was associated with lower risk for AD (hazard ratio, 0.91; 95% confidence interval, 0.83-0.98; p=0.015). Compared with subjects in the lowest MeDi tertile, subjects in the middle MeDi tertile had a hazard ratio of 0.85 (95% confidence interval, 0.63-1.16) and those at the highest tertile had a hazard ratio of 0.60 (95% confidence interval, 0.42-0.87) for AD (p for trend=0.007). INTERPRETATION: We conclude that higher adherence to the MeDi is associated with a reduction in risk for AD.

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PubMed2005

Effect of smoking and time on cognitive function in the elderly without dementia.

OBJECTIVE: To examine the association between smoking and changes in cognitive function over time in elderly persons without dementia. METHODS: The results of neuropsychological tests grouped into domains of memory, abstract-visuospatial, and language, from several intervals over a 5-year period in 791 elderly patients without dementia or cognitive impairment. Smoking history was categorized as never, current, or past smokers and related to the slope of performance in each cognitive domain using generalized estimating equations. RESULTS: Performance in all cognitive domains declined over time. Memory performance declined more rapidly among current smokers aged >75 years than in nonsmokers similar in age, including those who never smoked or had quit smoking. The effect was stronger among those without an APOE-epsilon4 allele. There was no association between smoking and performance in any cognitive domain in persons aged <75 years, and there was no association between past smoking and performance on any of the three cognitive factors at any time interval in either age group. CONCLUSION: Current smokers aged >75 years perform more poorly on cognitive tests and appear to decline in memory more rapidly than their peers who do not smoke, especially if they lack the APOE-epsilon4 allele. Smoking does not affect cognitive performance in those persons aged <75 years.

Age Factors↗

PubMed2005

Disparities in the recording of Parkinson's disease on death certificates.

Although little is known regarding potential socioeconomic or racial bias in the recording of Parkinson's disease (PD) on death certificates, studies of incidence, prevalence, and the etiology of PD frequently rely on this type of data. A national population-based survey was linked to death certificate data to investigate the concordance of PD reported on death certificates for persons reporting PD during life. Logistic regression was used to identify independent factors associated with differential reporting of PD at death. Among decedents with PD reported during life, 54.8% had PD recorded on the death certificate. Nearly 70% of persons in higher income categories had PD recorded at death compared to 35.4% for those earning $10,000 or less. Age and gender adjusted odds of having PD recorded at death was 2.3 (1.1-3.9), for those with an annual income of $35,000 or more. Income differences remain significant in multivariable models after controlling for age, gender, race, census region, family size, rural residence, and number of chronic medical conditions. In conclusion, this study found socioeconomic bias in the reporting of PD at death. This bias is large enough to confound death certificate-based investigations of incidence, prevalence, and risk factors that differ across socioeconomic strata.

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PubMed2005

Relationship between plasma lipids and all-cause mortality in nondemented elderly.

OBJECTIVES: To investigate the relationship between plasma lipids and risk of death from all causes in nondemented elderly. DESIGN: Prospective cohort study. SETTING: Community-based sample of Medicare recipients, aged 65 years and older, residing in northern Manhattan. PARTICIPANTS: Two thousand two hundred seventy-seven nondemented elderly, aged 65 to 98; 672 (29.5%) white/non-Hispanic, 699 (30.7%) black/non-Hispanic, 876 (38.5%) Hispanic, and 30 (1.3%) other. MEASUREMENTS: Anthropometric measures: fasting plasma total cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and non-HDL-C, body mass index, and apolipoprotein E (APOE) genotype. clinical measures: neuropsychological, neurological, medical, and functional assessments; medical history of diabetes mellitus, heart disease, hypertension, stroke, and treatment with lipid-lowering drugs. Vital status measure: National Death Index date of death. Survival methods were used to examine the relationship between plasma lipids and subsequent mortality in younger and older nondemented elderly, adjusting for potential confounders. RESULTS: Nondemented elderly with levels of total cholesterol, non-HDL-C, and LDL-C in the lowest quartile were approximately twice as likely to die as those in the highest quartile (rate ratio (RR)=1.8, 95% confidence interval (CI)=1.3-2.4). These results did not vary when analyses were adjusted for body mass index, APOE genotype, diabetes mellitus, heart disease, hypertension, stroke, diagnosis of cancer, current smoking status, or demographic variables. The association between lipid levels and risk of death was attenuated when subjects with less than 1 year of follow-up were excluded (RR=1.4, 95% CI=1.0-2.1). The relationship between total cholesterol, non-HDL-C, HDL-C, and triglycerides and risk of death did not differ for older (>or=75) and younger participants (>75), whereas the relationship between LDL-C and risk of death was stronger in younger than older participants (RR=2.4, 95% CI=1.2-4.9 vs RR=1.6, 95% CI=1.02-2.6, respectively). Overall, women had higher mean lipid levels than men and lower mortality risk, but the risk of death was comparable for men and women with comparable low lipid levels. CONCLUSION: Low cholesterol level is a robust predictor of mortality in the nondemented elderly and may be a surrogate of frailty or subclinical disease. More research is needed to understand these associations.

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PubMed2004

Hyperinsulinemia and risk of Alzheimer disease.

OBJECTIVE: To explore the association between fasting insulin levels and dementia. METHODS: Fasting insulin levels were measured from frozen sera using solid-phase chemiluminescent enzyme immunoassay in a sample of elderly subjects chosen at random from a cohort of persons aged 65 years and older from northern Manhattan. Dementia was diagnosed using standard methods. Neuropsychiatric testing was available on all subjects at each follow-up interval. RESULTS: A total of 683 subjects without prevalent dementia were followed for 3,691 person-years and 149 persons developed dementia (137 Alzheimer disease [AD], 6 dementia associated with stroke, 6 other). The risk of AD doubled in the 39% of the sample with hyperinsulinemia (HR = 2.1; 95% CI: 1.5, 2.9) and was highest in people without diabetes. The HR relating presence of hyperinsulinemia or diabetes in 50% of our sample to AD was 2.2 (95% CI: 1.5, 3.1). The risk of AD attributable to the presence of hyperinsulinemia or diabetes was 39%. The HR of AD for the highest quartile of insulin compared to the lowest was 1.7 (95% CI: 1.0, 2.7; p for trend = 0.009). Hyperinsulinemia was also related to a significant decline in memory-related cognitive scores, but not to decline in other cognitive domains. CONCLUSIONS: Hyperinsulinemia is associated with a higher risk of AD and decline in memory.

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PubMed2004

Genetic influences on life span and survival among elderly African-Americans, Caribbean Hispanics, and Caucasians.

An investigation of the genetic influences on life span and survival was conducted among elderly African-Americans, Caribbean Hispanics, and Caucasians Medicare recipients (ages 65-104 years). Family history information on 13,161 parents and siblings was obtained. Heritability of life span varied by the age and by ethnic group being lowest for African-Americans. We recalculated the heritability coefficients for life span including only probands and their siblings, but the differences across ethnic groups persisted. In contrast the heritability of survival was more similar across ethnic groups but was similar to that for life span. Heritability coefficients for survival in probands and their siblings revealed little difference between ethnic groups and suggested that as much as 35% of the variation in survival may be genetically influenced. These results indicate that life span and survival are genetically influenced. Comparisons across generations and ethnic groups indicate that changes in environmental hygiene, social welfare, and health care systems are significant contributors to life span and survival, but genetic influences are also important. Identifying the genes associated with life span and survival will provide insight into how the genes interact with environment to influence aging in humans.

Age Factors↗

PubMed2004

Relation of plasma lipids to Alzheimer disease and vascular dementia.

BACKGROUND: The relation between plasma lipid levels and Alzheimer disease (AD) and vascular dementia (VaD), and the impact of drugs to lower lipid levels remains unclear. OBJECTIVE: To investigate the relation between plasma lipid levels and the risk of AD and VaD and the impact of drugs to lower lipid levels on this relationship. DESIGN AND SETTING: Cross-sectional and prospective community-based cohort studies. PARTICIPANTS: Random sample of 4316 Medicare recipients, 65 years and older, residing in northern Manhattan, NY. MAIN OUTCOME MEASURES: Vascular dementia and AD according to standard criteria. RESULTS: Elevated levels of non-high-density lipoprotein (HDL-C) and low-density lipoprotein cholesterol (LDL-C) and decreased levels of HDL-C were weak risk factors for VaD in either cross-sectional or prospective analyses. Higher levels of total cholesterol were associated with a decreased risk of incident AD after adjustment for demographics, apolipoprotein E genotype, and cardiovascular risk factors. Treatment with drugs to lower lipid levels did not change the disease risk of either disorder. CONCLUSIONS: We found a weak relation between non-HDL-C, LDL-C, and HDL-C levels and the risk of VaD. Lipid levels and the use of agents to lower them do not seem to be associated with the risk of AD.

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PubMed2004

Preservation of cognitive and functional ability as markers of longevity.

Longevity is a complex biological process for which the phenotypes have not been established. Preservation of cognitive and physical function may be important and preservation of these functions is, in part, inherited. We investigated the relation between rate of change in cognitive and functional abilities in probands and risk of death in their siblings. Probands were classified as showing no decline, slow, medium, or rapid rate of decline, based on the slope of change in cognitive and physical/functional factors over three or more assessments. Siblings of probands who did not decline on measures of memory, visuospatial/cognitive function or ADL skills were approximately half as likely to die as siblings of probands who had the most rapid decline. The reduction in risk of death in siblings of probands who did not decline in was primarily observed among siblings of probands who were older than 75 years, suggesting that genetic influences on life span may be greater at older ages. There was no association between probands' rate of change in language, IADL skills, upper or lower extremity mobility and risk of death in siblings. The results of the present study identify phenotypes associated with preserved cognitive and functional abilities which may serve as markers for longevity.

Activities of Daily Living↗

PubMed2004

Cancellation test performance in African American, Hispanic, and White elderly.

Shape and letter cancellation test performance was investigated among large samples of African American, Hispanic, and White non-demented elders. Ethnic minority elders took significantly longer to complete both tasks compared to Whites. An index of task efficiency, which simultaneously measures time and accuracy, suggested that slower time by minority elders was not related to a measurable effort to achieve greater accuracy. The frequency of commission errors was greater in our sample than in previous reports, especially among ethnic minority elders. Although significant differences were observed between the ethnic groups when matched for years of education, equating for literacy level eliminated all performance differences between African Americans and Whites on both cancellation tasks.

Black or African American↗

PubMed2004

Alcohol intake and risk of dementia.

OBJECTIVES: To examine the association between intake of alcoholic beverages and risk of Alzheimer's disease (AD) and dementia associated with stroke (DAS) in a cohort of elderly persons from New York City. DESIGN: Cohort study. SETTING: The Washington Heights Inwood-Columbia Aging Project. PARTICIPANTS: Nine hundred eighty community-dwelling individuals aged 65 and older without dementia at baseline and with data on alcohol intake recruited between 1991 and 1996 and followed annually. MEASUREMENTS: Intake of alcohol was measured using a semiquantitative food frequency questionnaire at baseline. Subjects were followed annually, and incident dementia was diagnosed using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria and classified as AD or DAS. RESULTS: After 4 years of follow-up, 260 individuals developed dementia (199 AD, 61 DAS). After adjusting for age, sex, apolipoprotein E (APOE)-epsilon 4 status, education, and other alcoholic beverages, only intake of up to three daily servings of wine was associated with a lower risk of AD (hazard ratio=0.55, 95% confidence interval=0.34-0.89). Intake of liquor, beer, and total alcohol was not associated with a lower risk of AD. Stratified analyses by the APOE-epsilon 4 allele revealed that the association between wine consumption and lower risk of AD was confined to individuals without the APOE-epsilon 4 allele. CONCLUSIONS: Consumption of up to three servings of wine daily is associated with a lower risk of AD in elderly individuals without the APOE epsilon-4 allele.

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PubMed2003

The Saitohin 'Q7R' polymorphism and tau haplotype in multi-ethnic Alzheimer disease and Parkinson's disease cohorts.

In a multi-ethnic cohort we analyzed the Saitohin (STH) gene 'Q7R' polymorphism in 200 late-onset Alzheimer's disease cases (LOAD), 60 Parkinson's disease cases with dementia (PDD), 84 Parkinson's disease cases without dementia and 458 controls. We found no significant differences in genotype or allele frequencies when LOAD or PD cases were compared to controls. Ethnic differences in STH genotype frequencies for cases and controls were observed and these were statistically significant (cases n=344, P<0.03; controls n=458, P<0.001). We also observed a trend in non-Hispanic white PDD cases with the STH 'QQ' (Tau H1/H1) genotype increased (76%) compared to PD cases without dementia (61.7%) and controls (56.6%); however, this difference was not statistically significant (PDD vs. controls OR 2.1; 95% CI: 0.8-5.8, P=0.2).

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PubMed2003

Stroke and the risk of Alzheimer disease.

BACKGROUND: Alzheimer disease (AD) and stroke are common in elderly individuals, but the relation between these 2 disorders remains uncertain. OBJECTIVE: To investigate the association between a clinical history of stroke and subsequent risk of AD. DESIGN: A cohort of 1766 Medicare recipients without dementia participated in a longitudinal follow-up study from 1992 through 1999 in upper Manhattan, New York, NY. History of stroke and presence of cardiovascular risk factors were ascertained at the onset of the study. Incidence rates for AD among those with and without stroke were calculated; proportional hazards ratios were computed using age at onset of the disease as the time-to-event variable. RESULTS: The annual incidence for AD was 5.2% among individuals with stroke vs 4% for those without stroke. The hazards ratio for AD among those with a history of stroke was 1.6 (95% confidence interval, 1.0-2.4) compared with those without stroke. Of the vascular risk factors, hypertension, diabetes, and heart disease, only diabetes related to risk of AD in the absence of stroke. Stroke remained weakly associated with AD in the absence of these factors, but risk significantly increased with the additional factors of hypertension (relative risk, 2.3; 95% confidence interval, 1.4-3.6), diabetes (relative risk, 4.6; 95% confidence interval, 2.2-9.5), or heart disease (relative risk, 2.0; 95% confidence interval, 1.2-3.2). CONCLUSIONS: Stroke is associated with AD among elderly individuals. The relation is strongest in the presence of known vascular risk factors. The observed association between stroke and AD might relate to an underlying systemic vascular disease process, or alternatively, to the additive effects of stroke and AD pathologic features, leading to an earlier age at onset of disease.

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PubMed2003

Antioxidant vitamin intake and risk of Alzheimer disease.

BACKGROUND: The generation of oxygen free radicals is involved in the pathogenesis of Alzheimer disease (AD). OBJECTIVE: To determine whether the intake of antioxidant vitamins decreases the risk of AD. METHODS: We investigated the relationship between AD and the intake of carotenes, vitamin C, and vitamin E in 980 elderly subjects in the Washington Heights-Inwood Columbia Aging Project who were free of dementia at baseline and were followed for a mean time of 4 years. Semiquantitative food frequency questionnaires were administered between baseline and the first follow-up visit. Cox proportional hazards regression models were conducted with quartiles of each vitamin intake as the exposure of interest and incident AD as the outcome, adjusted for age, level of education, sex, APOE epsilon4 status, ethnicity, and smoking. RESULTS: There were 242 incident cases of AD in 4,023 person-years of follow-up (6 per 100 person-years). Intake of carotenes and vitamin C, or vitamin E in supplemental or dietary (nonsupplemental) form or in both forms, was not related to a decreased risk of AD. Trend tests for the association between quartiles of total intake of vitamins C and E also were not significant. CONCLUSION: Neither dietary, supplemental, nor total intake of carotenes and vitamins C and E was associated with a decreased risk of AD in this study.

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