Abstract
Chronic pain is highly prevalent among the elderly and in cross sectional studies is associated with cognitive deficits upon detailed neuropsychiatric testing. Using a nationally-representative population-based study, we investigated the association between pain at cohort inception and longitudinal measures of memory and dementia probability over the following 12 years.
We studied Health and Retirement Study (HRS) participants who were interviewed in both 1998 and 2000. “Chronic pain” was defined as being often troubled by moderate or severe pain in both the 1998 and 2000 interviews. Based on data from each biennial telephone-based HRS evaluation through 2012, memory z-score and dementia probability were calculated from the validated HRS cognitive battery using published methodology. Linear mixed effects models were used to estimate the effect of chronic pain on the slope of an individual longitudinal cognitive trajectory, adjusted for baseline demographic, economic and health factors.
The 10,065 subjects (mean age 73 in 2000, 60% female) underwent a median of 5 biennial cognitive evaluations. Of these, 1,120 (11%) reported chronic pain. After controlling for other predictors in the model, chronic pain was associated with 7.5% (95% CI 2.8–12.2%) more rapid relative increase in dementia probability, and 10.3% (95% CI 3.9–16.8%) faster memory z-score decline, compared to those with no pain.
We conclude that, at a population level, there is a modest but significant independent association between chronic pain and subsequent accelerated cognitive decline. Chronic pain may place elders at risk of accelerated memory loss and dementia.