Functional constipation is associated with a decline in word recognition 2 years later in community-dwelling older adults: The Korean Frailty and Aging Cohort Study

Background: Constipation is one of the most common health problems among the elderly, and cognitive impairment is also a major health problem among the elderly. Identifying risk factors for cognitive impairment is important to prevent many cognitive disorders. Though studies on cognitive decline in patients with Parkinson’s disease are available, no study has explored the predictive effect of functional constipation on cognitive decline in non-Parkinson’s elderly individuals. This study aimed to determine the association between constipation and cognitive decline in community-dwelling older adults. Methods: : This is a 2-year longitudinal analysis of cohort study data, including 851 community-dwellers as participants at the baseline survey who took part in the Korean Frailty and Aging Cohort Study and completed a follow-up survey. A neuropsychological test (CERAD-K, the Consortium to Establish a Registry for Alzheimer's Disease Assessment Battery) and the Korean version of the Frontal Assessment Battery were used to evaluate comprehensive cognitive function. Functional constipation was defined according to the ROME IV criteria. Analysis of covariance was used to identify the association between functional constipation and cognitive decline statistically. Results: : Among the 851 participants, 8.9% had functional constipation. The mean age of the functional constipation group (78.6 ± 3.9) was higher than that of the non-constipation group (77.5 ± 3.8). Patients in the functional constipation group were more likely to have low physical activity (15.8% vs. 8.8%), polypharmacy (61.8% vs. 45.5%), and depression (30.3% vs. 17.4%). After adjusting for potential confounding factors, including age, low physical activity, polypharmacy, type 2 diabetes mellitus, depressive disorder, and baseline cognitive function test score, the mean changes in word recognition test scores from 2018 to 2020 were -0.071 and -0.524 in the no-constipation and constipation groups, respectively (P=0.009). Changes in other cognitive function tests showed a tendency to be lower in the constipation group (memory -0.138 vs. -0.489, recall -0.296 vs. -0.407, digit span -0.248 vs. -0.379, frontal assessment battery 0.281 vs. 0.12, trail making test 0.143 vs. 5.38), but were not significantly different. Conclusions: : Functional constipation at baseline was associated with a decline in word recognition after two years.