Use of anticholinergics and the risk of cognitive impairment in an African American population

BACKGROUND

Anticholinergic properties of certain medications often go unrecognized, and are frequently used by the elderly population. Few studies have yet defined the long-term impact of these medications on the incidence of cognitive impairment.

METHODS

We report a 6-year longitudinal, observational study, evaluating 1,652 community-dwelling African American subjects over the age of 70 years who were enrolled in the Indianapolis-Ibadan Dementia Project between 2001 and 2007 and who had normal cognitive function at baseline. The exposure group included those who reported the baseline use of possible or definite anticholinergics as determined by the Anticholinergic Cognitive Burden scale. Our main outcome measure was the incidence of cognitive impairment, defined as either dementia or cognitive impairment not dementia, or poor performance on a dementia screening instrument during the follow-up period.

RESULTS

At baseline, 53% of the population used a possible anticholinergic, and 11% used a definite anticholinergic. After adjusting for age, gender, educational level, and baseline cognitive performance, the number of definite anticholinergics was associated with an increased risk of cognitive impairment (odds ratio [OR] 1.46, 95% confidence interval [CI] 1.07-1.99; p = 0.02), whereas the number of possible anticholinergics at baseline did not increase the risk (OR 0.96, 95% CI 0.85-1.09; p = 0.55). The risk of cognitive impairment among definite anticholinergic users was increased if they were not carriers of the APOE epsilon4 allele (OR 1.77, 95% CI 1.03-3.05; p = 0.04).

CONCLUSIONS

Limiting the clinical use of definite anticholinergics may reduce the incidence of cognitive impairment among African Americans.

A comparison of cardiovascular disease risk factor biomarkers in African Americans and Yoruba Nigerians

OBJECTIVE

Classical risk factors for coronary artery disease are changing in the developing world while rates of cardiovascular disease are increasing in these populations. Newer risk factors have been identified for cardiovascular disease, but these have been rarely examined in elderly populations and not those of developing countries.

METHODS

This study was a cross-sectional comparison from a longitudinal, observational, epidemiologic study in which participants are interviewed at three-year intervals. The sample included 1510 African Americans from Indianapolis, Indiana, and 1254 Yoruba from Ibadan, Nigeria. We compared anthropomorphic measurements; biomarkers of endothelial dysfunction (plasminogen activator inhibitor type 1 [PAI-1 and E-selectin), inflammation (C-reactive protein), and lipid oxidation (8-isoprostane); and levels of lipids, homocysteine, folate, and vitamin B12.

RESULTS

Cholesterol, triglycerides, and low-density lipoprotein cholesterol levels were higher in African Americans. For markers of endothelial dysfunction, E-selectin and homocysteine differed between men, and PAI-1 was higher in the Yoruba. C-reactive protein differed only in women, but 8-isoprostane was higher in the Yoruba.

CONCLUSION

Higher lipid levels in African Americans are consistent with their Western diet and lifestyle. Oxidative stress appears to be higher in the Yoruba than in African Americans, which may be secondary to dietary differences. Whether these differences in classical and emerging risk factors account for the different rates of cardiovascular disease, dementia, or other morbidities in these two populations remains to be determined.

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-Alzheimer's Disease and Related Disorders Association criteria.

RESULTS

Logistic regression models showed interaction after adjusting for age and gender between APOE-epsilon4 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-epsilon4 allele, but not in those with APOE-epsilon4. There was no significant association between levels of triglycerides and AD risk in those without APOE-epsilon4.

CONCLUSIONS

There was a significant interaction between cholesterol, APOE-epsilon4, 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.

Transthyretin isoleucine-122 mutation in African and American blacks

The gene frequency of the transthyretin (TTR) mutation (Val122Ile) was studied in African and African-American populations. The African populations analyzed included the Zulu and Xhosa of South Africa, and Yorubas from the city of Ibadan, Nigeria. The African-American population included patients at the Veterans Affairs (VA) Medical Center, Indianapolis, and newborns from a local hospital in Indianapolis. The Val122Ile TTR mutation was identified in 1 of 55 Zulu, 0 of 34 Xhosa, 0 of 9 Nigerian subjects, 5 of 51 Veteran patients, and 3 of 103 newborns. Assuming the 2.91% prevalence in newborns to be the norm, there is a significant increased prevalence in the VA patient population.

Effect of oxidative stress on DNA damage and beta-amyloid precursor proteins in lymphoblastoid cell lines from a Nigerian population

The epsilon 4 allele of apolipoprotein E (APOE) is strongly associated with late-onset Alzheimer's disease (AD) in Caucasian populations, but our studies suggest that APOE epsilon 4 is not a risk factor for AD in Nigerian blacks and is a weak risk factor in African-Americans. The prevalence of AD is lower in Nigerians than in African-Americans. Increased oxidative damage to macromolecules in brain tissue by reactive oxygen species (ROS) has been reported in AD. Here we examined the effects of endogenous and induced oxidative stress on total (nuclear and mitochondrial) DNA damage in lymphoblastoid cell lines (5 probable AD and 3 controls) from Ibadan, Nigeria. Cells were exposed to 200 microM t-butyl peroxide (a generator of ROS) for 4 hours. Total DNA was isolated and digested with nuclease P1 and alkaline phosphatase. DNA fragments were separated by HPLC and the levels of 8-hydroxy-2'-deoxyguanosine (OH8dG, an indicator of DNA damage) and deoxyguanosine (dG) determined. We did not detect a significant difference in the OH8dG/dG ratio in untreated or treated cell lines in the two groups, and this was independent of APOE genotype. We also examined, by Western blotting, the level of beta-amyloid precursor protein (APP) which is involved in AD. The level of the heat shock protein (HSP-70) was examined as a control. There was a slight decrease in levels of APP and HSP-70 following treatment. Studies in cell lines from Caucasian subjects have shown an increase in mitochondrial DNA damage following oxidative challenge. Our preliminary results suggest that African populations are less vulnerable to chemical-induced oxidative DNA damage.

Serum cholesterol, APOE genotype, and the risk of Alzheimer's disease: a population-based study of African Americans

A significant interaction among total serum cholesterol (TC), APOE genotype, and AD risk was found in a population-based study of elderly African Americans. Increasing TC was associated with increased AD risk in the group with no epsilon4 alleles, whereas TC was not associated with increased AD risk in the group with one or more epsilon4 alleles. Further study of the relationship between cholesterol and APOE genotype is needed to confirm this association, but the results suggest that cholesterol may be a potentially modifiable environmental risk factor for AD.

Alcohol related dementia: proposed clinical criteria

Current diagnostic criteria for Alcohol Related Dementia (ARD) are based almost exclusively on clinical judgment. Moreover, there are no guidelines available to assist the clinician or the researcher in distinguishing Alcohol Related Dementia from other causes of dementia such as Alzheimer's Disease (AD). However, this distinction may have implications for the prognosis and treatment of patients. In this article, provisional diagnostic criteria for establishing a diagnosis of Alcohol Related Dementia are proposed for further study. The criteria are based on the available literature on the relationship between alcohol consumption and dementia and were modeled after existing diagnostic criteria for AD and Vascular Dementia. Validity of these criteria for distinguishing AD from ARD will require further study.

Polymorphisms in the human apolipoprotein-J/clusterin gene: ethnic variation and distribution in Alzheimer's disease

Apolipoprotein-J/clusterin (APOJ/CLI) shares many biological properties with apolipoprotein-E (APOE) including, but not limited to, avid binding with beta-amyloid peptide. Thus, APOJ/CLI warrants scrutiny as a candidate Alzheimer's disease (AD) susceptibility gene. We identified seven nucleotide sequence polymorphisms in APOJ/ CLI, two of which, in exon 7, after the predicted amino acid sequence. The JVIIB variant is an asparagine-to-histidine substitution, which deletes a glycosylation signal at amino acid 317; the JVIIC variant is an aspartate-to-asparagine substitution, which forms a new glycosylation signal at position 328. Both of these coding variants, as well as two neutral polymorphisms in exon 2, were more frequent in African-Americans than Hispanics and were rare in Caucasians. However, no individual coding or noncoding variant was consistently associated with AD. At the population level, APOJ/CLI polymorphisms are frequent among persons of African descent, but probably do not alter susceptibility to AD.

Neuropsychological subgroups of dementia of the Alzheimer's type

Neuropsychological aspects of Dementia of the Alzheimer's Type (DAT) was considered using the scores from the Cambridge Cognitive Examination (CAMCOG) portion of the Cambridge Index of Mental Disorders in the Elderly (CAMDEX). CAMCOG scores for 51 DAT patients and 79 normal subjects were cluster analyzed. Results showed that the CAMCOG was effective in separating normal from demented subjects. The four subgroups of DAT patients differed more in "level" of impairment than for specific neuropsychological function. However, each level was characterized by losses in specific neuropsychological functions. Higher functioning groups exhibited greatest losses in memory skills, while the lowest functioning group showed greater loss of language skills.

CAMDEX. A standardised instrument for the diagnosis of mental disorder in the elderly with special reference to the early detection of dementia

A new interview schedule for the diagnosis and measurement of dementia in the elderly is described. The schedule named the Cambridge Mental Disorders of the Elderly Examination (CAMDEX), consists of three main sections: A structured clinical interview with the patient to obtain systematic information about the present state, past history and family history; a range of objective cognitive tests which constitute a mini-neuropsychological battery; a structured interview with a relative or other informant to obtain independent information about the respondent's present state, past history and family history. The CAMDEX is acceptable to patients, has a high inter-rater reliability and the cognitive section has been shown to have high sensitivity and specificity.

A two-year clinical experience with lithium

A two year clinical experience with lithium has been described. Our results can be summarized as follows:

Effect on active mania

Over seventy per cent of the manic patients in this study were controllable with lithium alone.

An additional twenty per cent with severe mania had to be stabilized by haloperidol, but were maintained by lithium once the acute phase subsided.

When a patient maintained on lithium shows prodromal symptoms of hypomania an increase in the dose of lithium is often, and for some patients regularly, an effective control for the incipient manic attack.

Some patients required periodic treatment for residual depression. Decreasing the dose of lithium, and adding an anti-depressant has been found to be effective, even in some cases where an antidepressant alone had previously failed to prevent repeated depressions. Merely decreasing the dose of lithium was not found to be effective.

Those who relapsed completely tended to be more hostile and suspicious, and in the authors' experience, ultimately showed schizophrenic features.

One relapse, especially when subsequent to the patient's discontinuing his own medication, does not mean that the patient cannot thereafter, be stabilized on lithium. One relapse should not be taken to mean ultimate failure, when a decrease in severity or frequency of attacks would be a worthwhile goal.