O. Gureje

Prevalence of cognitive impairment Data from the Indianapolis Study of Health and Aging

Background: The epidemiology and natural history of cognitive impairment that is not dementia is important to the understanding of normal aging and dementia. Objective: To determine the prevalence and outcome of cognitive impairment that is not dementia in an elderly African American population. Method: A two-phase, longitudinal study of aging and dementia. A total of 2212 community-dwelling African American residents of Indianapolis, IN, aged 65 and older were screened, and a subset (n = 351) received full clinical assessment and diagnosis. Subsets of the clinically assessed were seen again for clinical assessment and rediagnosis at 18 and 48 months. Weighted logistic regression was used to generate age-specific prevalence estimates. Results: The overall rate of cognitive impairment among community-dwelling elderly was 23.4%. Age-specific rates indicate increasing prevalence with increasing age: 19.2% for ages 65 to 74 years, 27.6% for ages 75 to 84 years, and 38.0% for ages 85+ years. The most frequent cause of cognitive impairment was medically unexplained memory loss with a community prevalence of 12.5%, followed by medical illness–associated cognitive impairment (4.0% prevalence), stroke (3.6% prevalence), and alcohol abuse (1.5% prevalence). At 18-month follow-up, 26% (17/66) of the subjects had become demented. Conclusions: Cognitive impairment short of dementia affects nearly one in four community-dwelling elders and is a major risk factor for later development of dementia.

Cholesterol, APOE genotype, and Alzheimer disease: An epidemiologic study of Nigerian Yoruba

Objective: To examine the relationship between cholesterol and other lipids, APOE genotype, and risk of Alzheimer disease (AD) in a population-based study of elderly Yoruba living in Ibadan, Nigeria. Methods: Blood samples and clinical data were collected from Yoruba study participants aged 70 years and older (N = 1,075) as part of the Indianapolis-Ibadan Dementia Project, a longitudinal epidemiologic study of AD. Cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglyceride levels were measured in fasting blood samples. DNA was extracted and APOE was genotyped. Diagnoses of AD were made by consensus using National Institute of Neurologic Disorders/Stroke-Alzheimers Disease and Related Disorders Association criteria. Results: Logistic regression models showed interaction after adjusting for age and gender between APOE-ε4 genotype and biomarkers in the risk of AD cholesterol*genotype (p = 0.022), LDL*genotype (p= 0.018), and triglyceride*genotype (p = 0.036). Increasing levels of cholesterol and LDL were associated with increased risk of AD in individuals without the APOE-ε4 allele, but not in those with APOE-ε4. There was no significant association between levels of triglycerides and AD risk in those without APOE-ε4. Conclusions: There was a significant interaction between cholesterol, APOE-ε4, and the risk of Alzheimer disease (AD) in the Yoruba, a population that has lower cholesterol levels and lower incidence rates of AD compared to African Americans. APOE status needs to be considered when assessing the relationship between lipid levels and AD risk in population studies.

Epidemiology of dementia in Nigeria: results from the Indianapolis-Ibadan study.

We determined the prevalence of dementia in a cohort of 2494 elderly Nigerians residents in Idikan Community, Ibadan, Nigeria. We utilized the Community Screening Instrument for Dementia to select subjects for clinical assessment in the second stage. The findings were compared with those of 2212 African Americans living in Indianapolis, studied simultaneously using similar methodology. The overall age‐adjusted prevalence rates of dementia and Alzheimers disease in Ibadan were 2.29% and 1.41%, respectively. These rates were much lower than the respective values of 8.24% and 6.24% obtained for African Americans. In Ibadan, Alzheimers disease accounted for 64.3% of the cases, with old age and female gender being the significant risk factors, whilst ‘living with others’ appeared to be protective (P < 0.05). Amongst African Americans, on the other hand, old age, rural living below the age of 19 years, low educational attainment and family history of dementia were the risk factors. There was a lack of association between Alzheimers disease and possession of the apolipoprotein E ε4 allele in the Nigerian sample, unlike the finding in African Americans, where significant association was shown. In addition, the frequencies of the vascular risk factors investigated were lower in Nigerians.

Behavioral and Caregiver Reaction of Dementia as Measured by the Neuropsychiatric Inventory in Nigerian Community Residents

BACKGROUND The Neuropsychiatric Inventory (NPI) has been used to assess behavioral symptoms of dementia in the United States, Taiwan, Japan, and Italy. METHOD This report evaluates the use of the NPI to assess behavioral symptoms of dementia in a population of Yoruba, Nigerians aged 65 years and older who are subjects in the Indianapolis-Ibadan Dementia Project. In this study, the NPI, Blessed Dementia Scale, and Mini-Mental State Examination (MMSE) were used to assess Nigerian subjects with dementia. For this study the NPI was translated, back translated, and harmonized into Yoruba. RESULTS The harmonized version of the NPI showed good interrater and test-retest reliability. The Cronbach alpha on 40 subjects was .80 for total severity score, .73 for frequency, and .73 for distress, indicating good internal consistency. The MMSE correlated with the NPI total score and severity scores of delusion, hallucination, and agitation, whereas the Blessed correlated with the NPI total score and severity scores of depression, anxiety, and nighttime behavior. CONCLUSIONS The NPI was found to be a reliable tool to assess behavioral symptoms and caregiver distress of dementia in the Yoruba. Behavioral disturbances were as common in the Yoruba patients with dementia as in studies in other countries that have used the NPI, but the pattern of behavioral disturbances and caregiver response varied among the countries.

The development of a semi-structured home interview (CHIF) to directly assess function in cognitively impaired elderly people in two cultures.

BACKGROUND Assessing function is a crucial element in the diagnosis of dementia. This information is usually obtained from key informants. However, reliable informants are not always available. METHODS A 10-item semi-structured home interview (the CHIF, or Clinician Home-based Interview to assess Function) to assess function primarily by measuring instrumental activities of daily living directly was developed and tested for inter-rater reliability and validity as part of the Indianapolis-Ibadan dementia project. The primary validity measurements were correlations between scores on the CHIF and independently gathered scores on the Blessed Dementia Scale (from informants) and the Mini-mental State Examination (MMSE). Sensitivities and specificities of scores on the CHIF and receiver operator characteristic (ROC) curves were constructed with dementia as the dependent variable. RESULTS Inter-rater reliability for the CHIF was high (Pearsons correlation coefficient 0.99 in Indianapolis and 0.87 in Ibadan). Internal consistency, in both samples, was good (Cronbachs alpha 0.95 in Indianapolis and 0.83 in Ibadan). Scores on the CHIF correlated well with the Blessed Dementia scores at both sites (-0.71, p < 0.0001 for Indianapolis and -0.56, p < 0.0001 for Ibadan) and with the MMSE (0.75, p < 0.0001 for Indianapolis and 0.44, p < 0.0001 for Ibadan). For all items at both sites, the subjects without dementia performed significantly better than those with dementia. The area under the ROC curve for dementia diagnosis was 0.965 for Indianapolis and 0.925 for Ibadan. CONCLUSION The CHIF is a useful instrument to assess function directly in elderly participants in international studies, particularly in the absence of reliable informants.

Cognitive impairment in community-dwelling older Nigerians: Clinical correlates and stability of diagnosis

To determine correlates and outcome of cognitive impairment without dementia in community‐dwelling elderly Nigerians. A total of 2487 community residents aged 65 years and over were screened using the Community Screening Interview for Dementia. A subset of 423 individuals received diagnostic clinical evaluation. Participants were diagnosed normal, demented, or cognitive impairment no dementia (CIND). Follow‐up clinical diagnostic evaluation was conducted on CIND subjects approximately 2 years later. One hundred and fifty‐two persons were diagnosed CIND. Eighty‐seven CIND subjects were seen at follow‐up assessment, 14 (16.1%) had converted to dementia, 22 (25.3%) reverted to normal, and 51 (58.6%) remained CIND. No baseline factors predicted later development of dementia amongst the CIND subjects. CIND subjects who reverted to normal tended to be male and to have higher baseline cognitive scores. Apolipoprotein status was not related to diagnosis at follow‐up. CIND is common in community‐dwelling Nigerians. Although the outcome is variable, it does represent a high‐risk group for subsequent dementia.

Weight loss and incident dementia in elderly Yoruba Nigerians: a 10-year follow up study

BACKGROUND The relationship between weight and dementia risk has not been investigated in populations with relatively low body mass index (BMI) such as the Yoruba. This study set out to achieve this objective using a prospective observational design. METHODS The setting was Idikan Ward in Ibadan City, Nigeria. The participants were all aged 65 years or older and were enrolled in the Indianapolis-Ibadan Dementia Project. Repeated cognitive assessments and clinical evaluations were conducted to identify participants with dementia or MCI during 10 years of follow-up (mean duration: 5.97 years). BMI measures, information on alcohol, smoking history, cancer, hypertension, diabetes, heart attack, stroke and depression were collected at each follow-up evaluation. Mixed effect models adjusted for covariates were used to examine the differences in BMI among participants who developed dementia or MCI and those who remained cognitively normal during the follow-up. RESULTS This analysis included 1559 participants who had no dementia at their first BMI measurements. There were 136 subjects with incident dementia, 255 with MCI and 1168 with normal cognition by the end of the study. The mean BMI at baseline was higher for female participants (22.31; SD = 4.39) than for male (21.09; SD = 3.61, p < 0.001). A significantly greater decline in BMI was found in those with either incident dementia (p < 0.001) or incident MCI (p < 0.001) compared to normal subjects. CONCLUSION Decline in BMI is associated with incident MCI and dementia in elderly Yoruba. This observation calls for close monitoring of weight loss in elderly individuals which may indicate future cognitive impairment for timely detection and tailored interventions.