Associations between pain and cognitive impairment in older adults: findings from the birjand longitudinal aging study

BACKGROUND: Chronic pain is highly prevalent among older adults and has been shown to be associated with differences in cognitive function. While pain intensity reflects the severity of pain, pain interference assesses the extent to which pain disrupts daily activities. Distinguishing between these dimensions of pain and their associations with cognitive function may improve understanding of how pain relates to cognitive health in older populations. METHODS: This cross-sectional study was conducted using baseline data from the Birjand Longitudinal Aging Study (BLAS). Pain was assessed using the Brief Pain Inventory (BPI), with pain severity defined as the mean of items 3-6 and pain interference assessed using item 9. Cognitive impairment was determined based on the combination results of the Six Item Cognitive Impairment Test (6-CIT), the Abbreviated Mental Test Score (AMTS), and the Category Fluency Test (CFT). Multiple logistic regression models were employed to examine associations between pain measures and cognitive impairment, adjusting for potential confounders. RESULTS: Among 1,343 participants (mean age: 69.73 ± 7.53 years; 51.82% female), 59.64% were classified as cognitively impaired. In analyses adjusted for covariates selected based on the DAG-informed model, both pain severity and pain interference were significantly associated with cognitive impairment (pain severity: OR = 1.09, 95% CI: 1.02-1.15, p = 0.005; pain interference: OR = 1.13, 95% CI: 1.04-1.22, p = 0.003). Sensitivity analyses showed consistent findings, with significant associations observed for both pain severity (OR = 1.12, 95% CI: 1.03-1.21, p = 0.004) and pain interference (OR = 1.16, 95% CI: 1.05-1.28, p = 0.002). CONCLUSION: Both pain severity and pain interference were significantly associated with cognitive impairment after adjustment for key confounders. These findings highlight the importance of addressing pain's impact on daily functioning to mitigate cognitive decline in this population.