Cognitive impairment in elderly women: the relative importance of selected genes, lifestyle factors, and comorbidities

Predictors of poor cognitive status among older Malaysian adults: baseline findings from the LRGS TUA cohort study

BACKGROUND

Concepts of successful aging (SA), usual aging (UA), and mild cognitive impairment (MCI) have been developed to identify older adults at high risk of Alzheimer's diseases (AD), however, the predictors have rarely been investigated in a single study. Thus, this study aims to explore the risk factors of MCI as compared to UA and SA among older adults, in a large community based cohort study in Malaysia.

METHOD

1993 subjects from four states in Malaysia were recruited. A comprehensive interview-based questionnaire was administered to determine socio-demographic information, followed by assessments to evaluate cognitive function, functional status, dietary intake, lifestyle and psychosocial status. Risk factors of cognitive impairment were assessed using the ordinal logistic regression (OLR).

RESULT

The prevalence of SA, UA and MCI in this study was 11, 73 and 16 % respectively. OLR indicated that higher fasting blood sugar, hyperlipidemia, disability, lower education level, not regularly involved in technical based activities, limited use of modern technologies, lower intake of fruits and fresh fruit juices and not practicing calorie restriction were among the risk factors of poor cognitive performance in this study.

CONCLUSION

This study will be a stepping stone for future researchers to develop intervention strategies to prevent cognitive decline.

Association of a dopamine beta-hydroxylase gene variant with depression in elderly women possibly reflecting noradrenergic dysfunction

BACKGROUND

Depression has a multifactorial etiology which involves genetic factors and comorbid diseases.

METHODS

A cross-sectional sample of 1371 elderly women (mean age=69.2 years) was examined. Detailed information on their health was obtained. Cognitive functions were assessed by the Short Blessed Test and the Animal Naming Task. A 19 bp insertion/deletion polymorphism in the dopamine beta-hydroxylase (DBH) gene, the apolipoprotein (APOE) epsilon2/epsilon3/epsilon4 variation and 5-HTTLPR in the serotonin transporter gene were genotyped.

RESULTS

Depression was univariately associated with homozygosity for the DBH gene 19 bp deletion allele (odds ratio [OR]=1.96, 95% confidence intervals [95% CI]=1.17-3.29, p=0.01), family history of depression (OR=3.86, 95% CI=1.85-8.06, p=0.0003), a composite measure of cardiovascular diseases (OR=1.96, 95% CI=1.11-3.47, p=0.02), cognitive impairment assessed by the Short Blessed Test (OR=3.88, 95% CI=1.29-11.64, p=0.02) and performance on the Animal Naming Task (OR=0.74, 95% CI=0.59-0.93, p=0.01). The strength of the association of DBH genotype with depression essentially remained unchanged after correction for other variables in a multivariate model. This association may reflect noradrenaline dysfunction in the brain.

Cognitive performance in elderly women: significance of the 19bp insertion/deletion polymorphism in the 5' flank of the dopamine beta-hydroxylase gene, educational level, body fat measures, serum triglyceride, alcohol consumption and age

BACKGROUND

Genetic and environmental factors influence cognitive aging. The gene encoding dopamine beta-hydroxylase (DBH) could be one such factor since this hydroxylase converts dopamine to norepinephrine both of which are involved in cognition regulation.

OBJECTIVE

To assess the effect of the 19bp insertion/deletion polymorphism in the 5' flank of the DBH gene on cognitive performance in elderly women relative to other factors of cognitive aging.

METHODS

We examined a cross-sectional sample of 1371 postmenopausal women. Cognitive abilities were assessed by the 6-item orientation-memory-concentration test. The 19bp insertion/deletion polymorphism of the DBH gene was genotyped and apolipoprotein E (APOE) epsilon4 allele status was determined. In addition blood pressure, body fat mass and blood lipids were measured. Information was also obtained by personal interviews. Data were analyzed by regression analysis.

RESULTS

Cognition was univariately associated with DBH genotype (p = 0.04). A univariate association of borderline significance was observed for APOE epsilon4 allele status (p = 0.07). Exclusion of women with severe cognition impairment did not alter the strength of the association with the DBH gene polymorphism markedly (p = 0.06) but obliterated the weak association between APOE epsilon4 allele status and cognition. The association of the DBH gene polymorphism with cognition persisted after adjustment for other variables (p = 0.03).

CONCLUSIONS

The 19bp insertion/deletion polymorphism of the DBH gene influences cognition in elderly women and might have a stronger effect than APOE epsilon4 allele status on mild cognitive impairment. Both genetic polymorphisms had a significantly smaller impact on cognition than age, education, alcohol consumption and body fat measures.