Association between urinary flow rate and cognition in the elderly: A cross-sectional study

Background Age-related lower urinary tract symptoms (LUTS) is a common disease in the elderly. The reduction of urinary flow rate (UFR) as an assessment of LUTS is associated with cognitive impairment. The association between UFR and cognitive performance has not been studied to date. Methods We used data from the 2011 to 2014 U.S. National Health and Nutrition Examination Survey (NHANES). Finally, 2,724 participants aged 65-80 with available data on UFR and cognitive assessments were included. The cognitive function assessment used the digit symbol substitution test (DSST), Animal Fluency Test (AFT) and the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) immediate recall test. Multivariate logistic regressions were used to assess the association between UFR (exposure) and cognitive performance (outcome). Additionally, to ensure the reliability of data analysis, we converted UFR into categorical variables through tertile and then calculated the P for trend. Results Among 2,724 participants, the mean (SD) age was 69.26 (6.65) years, and 54.56% were women. After adjusting for covariates, UFR showed a positive correlation with DSST score (β = 2.00, [95%Cl:1.20-2.80], P<0.0001), AFT score (β = 0.57,[95%Cl:0.28-0.87], P=0.0001), CERAD immediate score(β = 0.24, [95%Cl:0.01-0.47], P=0.0435). In addition, we found a similar linear trend when UFR was regarded as a categorical variable (tertile) (P for trend <0.0001(both in AFT and DSST); P for trend =0.0403 in CERAD immediate test). Conclusions The decrease of UFR is related to cognitive decline in the elderly, which may suggest that UFR may be a clinical marker of predicting cognitive decline.