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White blood cell count and psychomotor cognitive performance in the elderly
Author(s) -
Kao TungWei,
Chang YawWen,
Chou ChihChieh,
Hu Jung,
Yu YauHua,
Kuo HsuKo
Publication year - 2011
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.2010.02438.x
Subject(s) - quartile , digit symbol substitution test , national health and nutrition examination survey , white blood cell , psychomotor learning , medicine , multilevel model , linear regression , cognition , confidence interval , pathology , statistics , mathematics , psychiatry , population , alternative medicine , environmental health , placebo
Eur J Clin Invest 2011; 41 (5): 513–520 Abstract Background White blood cell (WBC) count is associated with many inflammatory diseases such as cardiovascular disease, diabetes and hypertension. Research on the relationship of WBC count and cognition in the elderly is relatively sparse. This study examined the association between WBC count and cognitive performance in older adults. Methods Data from the National Health and Nutrition Examination Survey (1999–2002) containing 1670 older adults were analysed. Every subject completed a household interview, examination of digit symbol substitution test (DSST) scores, WBC count measurement and a questionnaire regarding personal health. WBC count was restricted to the normal range and divided into quartiles, using a multiple hierarchical regression model to estimate the relationship between WBC counts and DSST scores. Quartile‐based analysis with an extended‐model approach was used for further covariates adjustment. Trends test examining the associations across increasing quartiles of WBC counts and DSST scores were also conducted. Results In the multiple hierarchical regression model, the β coefficient, representing the change of DSST scores for each 1000 cells uL −1 increase in WBC count, was −0·097 ( R 2 = 0·343, P < 0·001). After additional competent covariates adjustment, the negative correlation remained (all P < 0·001). In quartile‐based multiple linear regression, the negative trends between DSST scores and WBC count quartiles in the stratified comparison with extended‐model approach were all statistically significant ( P for trends <0·001). Conclusions Higher WBC counts, even within the normal range, were associated with poor psychomotor cognitive performance in the elderly.