Browsing by Author "Purnell, Christianna"

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    APOE ε4 and the risk for Alzheimer disease and cognitive decline in African Americans and Yoruba
    (Cambridge University Press, 2014-06) Hendrie, Hugh C.; Murrell, Jill; Baiyewu, Olusegun; Lane, Kathleen A.; Purnell, Christianna; Ogunniyi, Adesola; Unverzagt, Frederick W.; Hall, Kathleen; Callahan, Christopher M.; Saykin, Andrew J.; Gureje, Oye; Hake, Ann; Foroud, Tatiana; Gao, Sujuan; Department of Psychiatry, IU School of Medicine
    Background There is little information on the association of the APOEe4 allele and AD risk in African populations. In previous analyses from the Indianapolis-Ibadan dementia project, we have reported that APOE ε4 increased the risk for Alzheimer’s disease (AD) in African Americans but not in Yoruba. This study represents a replication of this earlier work using enriched cohorts and extending the analysis to include cognitive decline. Methods In this longitudinal study of two community dwelling cohorts of elderly Yoruba and African Americans, APOE genotyping was conducted from blood samples taken on or before 2001 (1,871 African Americans & 2,200 Yoruba). Mean follow up time was 8.5 years for African Americans and 8.8 years for Yoruba. The effects of heterozygosity or homozygosity of ε4 and of the possession of e4 on time to incident AD and on cognitive decline were determined using Cox’s proportional hazards regression and mixed effects models. Results After adjusting for covariates, one or two copies of the APOE ε4 allele were significant risk factors for incident AD (p < 0.0001) and cognitive decline in the African-American population (p < 0001). In the Yoruba, only homozygosity for APOE ε4 was a significant risk factor for AD (p = 0.0002) but not for cognitive decline (p = 0.2346), however, possession of an e4 allele was significant for both incident AD (p = 0.0489) and cognitive decline (p = 0.0425). Conclusions In this large longitudinal comparative study, APOE ε4 had a significant, but weaker, effect on incident AD and on cognitive decline in Yoruba than in African Americans. The reasons for these differences remain unclear.
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    The Association of Early Life Factors and Declining Incidence Rates of Dementia in an Elderly Population of African Americans
    (Oxford University Press, 2018-04-16) Hendrie, Hugh C.; Smith-Gamble, Valerie; Lane, Kathleen A.; Purnell, Christianna; Clark, Daniel O.; Gao, Sujuan; Psychiatry, School of Medicine
    Objectives: To explore the possible association of childhood residence, education levels, and occupation with declining incidence rates of dementia in 2 cohorts of elderly African Americans. Methods: African Americans residing in Indianapolis without dementia were enrolled in 1992 and 2001 and evaluated every 2-3 years. The cohorts consist of 1,440 participants in 1992 and 1,835 participants in 2001 aged 70 years and older. Cox proportional hazard regression models were used to compare cohort differences in dementia and Alzheimer's disease (AD) risk. Results: The 2001 cohort had significantly decreased risk of both incident dementia and AD (hazard ratio [HR]: 0.62/0.57 for dementia/AD). Years of education was associated with decreased risk of dementia (HR = 0.93; p = .0011). A significant interaction (p = .0477) between education and childhood rural residence was found for the risk of AD that higher education level is significantly associated with reduced AD risk (HR = 0.87) in participants with childhood rural residence, but no association in those with urban upbringing. The cohort difference for dementia rates were attenuated by adjusting for the 3 risk factors but remained significant (HR = 0.75; p = .04). Discussion: These results emphasize the importance of early life factors including rural residence and education for the risk for dementia later in life.
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    Changes of glucose levels precede dementia in African Americans with diabetes but not in Caucasians
    (Elsevier, 2018-12) Hendrie, Hugh C.; Zheng, Mengjie; Lane, Kathleen A.; Ambuehl, Roberta; Purnell, Christianna; Li, Shanshan; Unverzagt, Frederick W.; Murray, Michael D.; Balasubramanyam, Ashok; Callahan, Chris M.; Gao, Sujuan; Psychiatry, School of Medicine
    INTRODUCTION Changes in glucose levels may represent a powerful metabolic indicator for dementia in African Americans with diabetes. It is unclear whether these changes also occur in Caucasians. METHODS A secondary data analysis using electronic medical records from 5228 African Americans and Caucasians 65 years and older. Mixed effects models with repeated serum glucose measurements were used to compare changes in glucose levels between African Americans and Caucasian patients with and without incident dementia. RESULTS African Americans and Caucasians with diabetes had significantly different changes in glucose levels by dementia status (p<0.0001). African Americans experienced a significant decline in glucose levels before the dementia diagnosis (estimated glucose decline 1.3421 mg/dL per year, p<0.0001) than those who did not develop dementia. Caucasians with and without dementia showed stable glucose levels over time (p=0.3071). DISCUSSION Significant changes in glucose levels precede dementia in African American patients with diabetes but not in Caucasians.
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    Comorbidity Profile and Health Care Utilization in Elderly Patients with Serious Mental Illnesses
    (Elsevier, 2013-12) Hendrie, Hugh C.; Hay, Don; Lane, Kathleen A.; Gao, Sujuan; Purnell, Christianna; Munger, Stephanie; Smith, Faye; Dickens, Jeanne; Boustani, Malaz A.; Callahan, Christopher M.; Department of Psychiatry, IU School of Medicine
    Objectives Patients with serious mental illness are living longer. Yet there remain few studies that focus on health care utilization and its relationship to comorbidities in these elderly mentally ill patients. Design Comparative study. Information on demographics, comorbidities and health care utilization were taken from an electronic medical record system. Setting Wishard Health Services senior care and community mental health clinics. Participants Patients age 65 years and over-255 patients with serious mental illness (schizophrenia, major recurrent depression and bipolar illness) attending a mental health clinic and a representative sample of 533 non-demented patients without serious mental illness attending primary care clinics. Results Patients having serious mental illness had significantly higher rates of medical emergency room visits (p=0.0027) and significantly longer lengths of medical hospitalizations (p<0.0001) than did the primary care control group. The frequency of medical comorbidities such as diabetes, coronary artery disease, congestive heart failure, chronic obstructive pulmonary disease, thyroid disease, and cancer were not significantly different between the groups. Hypertension was lower in the mentally ill group (p<0.0001). Reported falls (p<0.0001), diagnoses of substance abuse (p=0.02), and alcoholism (p=0.0016) were higher in the seriously mentally ill. The differences in health care utilization between the groups remained significant after adjusting for comorbidity levels, lifestyle factors, and attending primary care. Conclusions Our findings of higher rates of emergency care, longer hospitalizations, and increased frequency of falls, substance abuse, and alcoholism suggest the elderly seriously mentally ill remain a vulnerable population requiring an integrated model of health care.
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    Glucose level decline precedes dementia in elderly African Americans with diabetes
    (Elsevier, 2017-02) Hendrie, Hugh C.; Zheng, Mengjie; Li, Wei; Lane, Kathleen; Ambuehl, Roberta; Purnell, Christianna; Unverzagt, Frederick W.; Torke, Alexia; Balasubramanyam, Ashok; Callahan, Chris M.; Gao, Sujuan; Psychiatry, School of Medicine
    INTRODUCTION: High blood glucose levels may be responsible for the increased risk for dementia in diabetic patients. METHODS: A secondary data analysis merging electronic medical records (EMRs) with data collected from the Indianapolis-Ibadan Dementia project (IIDP). Of the enrolled 4105 African Americans, 3778 were identified in the EMR. Study endpoints were dementia, mild cognitive impairment (MCI), or normal cognition. Repeated serum glucose measurements were used as the outcome variables. RESULTS: Diabetic participants who developed incident dementia had a significant decrease in serum glucose levels in the years preceding the diagnosis compared to the participants with normal cognition (P = .0002). They also had significantly higher glucose levels up to 9 years before the dementia diagnosis (P = .0367). DISCUSSION: High glucose levels followed by a decline occurring years before diagnosis in African American participants with diabetes may represent a powerful presymptomatic metabolic indicator of dementia.
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    Statin Use, Incident Dementia and Alzheimer Disease in Elderly African Americans
    (International Society on Hypertension in Blacks, 2015) Hendrie, Hugh C.; Hake, Ann; Lane, Kathleen; Purnell, Christianna; Unverzagt, Frederick; Smith-Gamble, Valerie; Murrell, Jill; Ogunniyi, Adesola; Baiyewu, Olusegun; Callahan, Chris; Saykin, Andrew J.; Taylor, Stanley; Hall, Kathleen; Gao, Su; Department of Neurology, IU School of Medicine
    OBJECTIVE: To investigate the association between statin use, incident dementia, and Alzheimer disease (AD) in a prospective elderly African American cohort. DESIGN: Two stage design with a screening interview followed by a comprehensive in-home assessment conducted over an eight-year period. Diagnoses of incident AD and dementia were made by consensus. Statin use was collected at each evaluation. Measurements of low-density lipoprotein cholesterol (LDL), C-reactive protein (CRP) and APOE genotype were obtained from baseline blood samples. Logistic regression models were used to test the association of statin use on incident dementia and AD and its possible association with lipid and CRP levels. SETTING: Indianapolis, Indiana. PARTICIPANTS: From an original cohort of 2629 participants, a subsample of 974 African Americans aged >70 years with normal cognition, at least one follow up evaluation, complete statin information, and biomarker availability were included. MAIN OUTCOME MEASURES: Incident dementia and incident AD. RESULTS: After controlling for age at diagnosis, sex, education level, presence of the APOE ε4 allele and history of stroke for the incident dementia model, baseline use of statins was associated with a significantly decreased risk of incident dementia (OR=.44, P=.029) and incident AD (OR=.40, P=.029). The significant effect of statin use on reduced AD risk and trend for dementia risk was found only for those participants who reported consistent use over the observational period (incident AD: P=.034; incident dementia: P=.061). Additional models found no significant interaction between baseline statin use, baseline LDL, or CRP level and incident dementia/AD. CONCLUSIONS: Consistent use of statin medications during eight years of follow-up resulted in significantly reduced risk for incident AD and a trend toward reduced risk for incident dementia.