Number of pain points and multisite pain in people 80 years and older in Thailand.

Introduction/Objectives: The factors influencing the number of pain sites (NPS) and multisite pain (MSP) in adults 80 years and older have not been thoroughly examined in many research. The purpose of this study was to estimate these drivers using Thailand's 3-wave national longitudinal data. Methods: We used data of people 80 years and older (analytic sample: n = 2450 observations) from the 2015, 2017, and 2022 Health, Aging, and Retirement in Thailand survey. Number of pain sites and multisite pain were measured using established metrics. The time-variant causes and outcomes were evaluated using fixed-effects regression. Results: The average NPS was 2.4 (SD = 3.1); the proportion of MSP was 46.1% and 31.4% for having ≥2 and ≥3 pain sites, respectively; and 42.8% reported moderate or severe pain on at least 1 pain site. Fixed-effects (FE) regressions showed that increasing age, subjective economic status, and work status decreased the NPS. Transitioning to live alone, past smoking, and an increase in depressive symptoms increased the NPS. Regarding FE regressions with MSP (≥2 and ≥3 pain sites), age and subjective economic status decreased the odds of MSP, transitioning to live alone, past smoking, depressive symptoms, and the number of chronic conditions increased the odds of MSP. Conclusions: Decreasing age, decreasing subjective economic status, not working, living alone, past smoking, depressive symptoms, and chronic conditions were associated with the NPS and/or MSP.