Pain characteristics and risk of scale-identified cognitive impairment among middle-aged and older Chinese adults: a longitudinal study from CHARLS

Cognitive impairment and chronic pain have become major public health challenges, adversely affecting the lives of middle-aged and older adults. However, longitudinal evidence on pain characteristics and subsequent cognitive outcomes in Chinese populations remains limited. We examined whether baseline pain characteristics were associated with the risk of developing scale-identified cognitive impairment among middle-aged and older Chinese adults. This longitudinal cohort study included 7,899 CHARLS participants aged 45 years and older who were free of scale-identified cognitive impairment at baseline in 2015 and had follow-up cognitive assessment data in 2020. Pain distribution and location were assessed by self-report. Cognitive function was measured using episodic memory and mental acuity tests, and scale-identified cognitive impairment was defined as a cognitive function score at least 1 SD below the wave-specific mean. Cox regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for sociodemographic characteristics, lifestyle factors, sleep duration, and number of chronic diseases. Over an average follow-up period of 60.1 months, 21.2% of participants developed scale-identified incident cognitive impairment. Compared with the no-pain group, those experiencing multi-site pain exhibited a modestly higher risk of incident cognitive impairment (adjusted HR = 1.18, 95% CI: 1.05 to 1.33). Subgroup analyses revealed that the risk remained significant among females (adjusted HR = 1.26, 95% CI: 1.05 to 1.51) and individuals aged < 60 years (adjusted HR = 1.21, 95% CI: 1.03 to 1.44). Participants with headache-associated pain had a higher risk of scale-identified incident cognitive impairment (adjusted HR = 1.33, 95% CI: 1.15 to 1.53) compared with those without pain. Multi-site pain and headache-associated pain were associated with modestly elevated risks of scale-identified incident cognitive impairment. Considering the scale-identified cognitive outcomes and self-reported pain assessment, these findings should be interpreted cautiously. Future studies with more detailed pain measures and longer follow-up are warranted.