Community‐Based Comprehensive Geriatric Assessment of Short‐ and Long‐Term Predictors of Cognitive Decline in Elderly Adults

Abstract

To the Editor: Only little is known regarding successful approaches to primary or secondary prevention of most dementia. There is a need for detecting and modifying specific risk factors assessable in the community. From a combined global and local viewpoint, a community-based comprehensive geriatric assessment (CGA) of older adults in a rural Japanese town was performed to investigate its association with cognitive status. Recent investigations have shown that physical performance is an important predictor of change in cognitive function1-3 and that blood pressure (BP) is associated with cognitive performance.4-6 How changes in cognitive function may relate to changes in physical assessments, brachial and central systolic BP and other cardiovascular and clinical endpoints was investigated after 3 and 5 years of follow-up. Annual community-based CGA of elderly adults living in Tosa (Kochi prefecture) has been performed since 2004. Of health check participants aged 75 to 99 in 2005 (reference; second year of project), 133 (94 women, 39 men, mean 2005 age 80.1) were followed up in 2008 and 108 (77 women, 31 men, mean 2005 age 79.9) again in 2010. Left brachial BP and right radial arterial pulse waves were noninvasively measured using oscillometry and tonometry (HEM-9000AI, Omron Healthcare Co., Ltd., Kyoto, Japan).7 SBP2 (radial augmentation index (AI) × (brachial SBP–brachial DBP) + brachial DBP) and AI were determined using pulse wave analysis.8 Because central SBP by direct measurement is reportedly closely associated with radial SBP2,8 radial SBP2 was used as the derived central aortic pressure. Subjects grouped in terms of declining, unchanged, or improving cognitive function were compared using one-way analysis of variance or chi-square tests, complemented by Student t-tests. P < .05 was considered statistically significant. In 2005, mean Mini–Mental State Examination (MMSE) score was 27.5 (range 24–30), mean Hasegawa Dementia Rating Scale—Revised (HDS-R) score was 26.8 (range 19–30), mean modified Kohs’ block design test score was 21.7 (range 2–46), and mean Clock Drawing Test (CDT) score was 8.5 (range 1–10) (Table 1). Improvement (or decline) in cognitive function was defined as an increase (or decrease) of three points on the MMSE. In 2008 (3-year follow-up), men were more likely to have declined than women (P = .04), CDT was larger (P = .01), Timed Up and Go was faster (P = .02), and serum creatinine was higher in the improved than in the unchanged group (P = .04). In 2010 (5-year follow-up), central systolic BP was higher in the declined than in the unchanged group (P = .02), and hemoglobin was higher in the improved than in the unchanged group (P = .002) (Table 1). Anemia in older adults is reportedly associated with greater risk of dementia in the next 11 years,9 perhaps related to chronic brain hypoxia. In the current study, central systolic BP was a predictor of cognitive decline at 5-year follow-up, and physical activity assessed according to the Timed Up and Go test was a short-term predictor of cognitive function. Slow gait was also a strong and early risk factor for cognitive decline in a study of 767 participants aged 70 and older studied over 36.5 months (dementia hazard ratio = 3.27, 95% confidence interval (CI) = 1.55–6.90).2 Other investigations also suggest that high BP in midlife increases the risk of dementia and Alzheimer's disease in older age. High systolic BP was a risk factor for dementia in younger elderly adults (<75) but not in older adults in a less-than-10-year prospective community-based cohort study.4 In a transverse investigation, central BP, but not brachial BP, was a sensitive indicator of cognitive function.6 This is in keeping with the current investigation confirming in older adults that central systolic BP, but not brachial systolic BP, was a statistically significant predictor of cognitive decline at five but not 3 years. Central hemodynamic variables are independently associated with organ damage and incident cardiovascular disease, suggesting that central BP may be different from BP measured on the arm.6, 10 It may thus be more relevant to the study of cognitive function, given that blood is delivered to the brain through the large central arteries. In conclusion, central BP is a long-term predictor of cognitive decline in older adults, whereas preserved physical activity, represented by the Timed Up and Go test is a short-term predictor of cognitive improvement. We would like to extend our thanks to all participants of this study. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. Author Contributions: Kikuchi: data analysis and writing of the manuscript. Sasaki, Oinuma, Yamanaka G., Okajima, Yamanaka T., Okumiya: data collection. Cornelissen, Matsubayashi, Otsuka: study concept. Sponsor's Role: None.