Global pain and aging: A cross-sectional study on age differences in the intensity of chronic pain among middle-aged and older adults in 20 countries

OBJECTIVES: This study aims to examine age differences in the intensity of chronic pain among middle-aged and older adults, where intensity is measured on a scale differentiating between chronic pain that is often troubling and likely requires intervention versus more endurable sensations. We aim to explore whether individual health and national gross domestic product (GDP) explain these differences as well.

METHODS: Cross-nationally harmonized data from 20 countries on self-reported intensity of chronic pain (0=no, 1=mild, 2=moderate, 3=severe) in 104,826 individuals aged 50+ observed in 2012-2013. Two-level hierarchical ordinal linear models with individuals nested within countries were used to isolate estimations from heterogeneity explained by methodological differences across single-country studies.

RESULTS: Overall, mean participant age was 66.9 (SD=9.9), 56.1% were women, and 41.9% of respondents reported any chronic pain. Chronic pain intensity rose sharply with age in some countries (e.g., Korea and Slovenia), but this association waned or reversed in other countries (e.g., the USA and Denmark). Cross-country variation and age differences in chronic pain were partly explained (85.5% and 35.8%, respectively) by individual-level health (especially arthritis), country-level wealth (as indicated by GDP per capita), and demographics.

DISCUSSION: Chronic pain intensity is not an inevitable consequence of chronological age, but the consequence of potential selection effects and lower activity levels combined with individual-level health and country-level wealth. Our findings suggest further investigation of health conditions and country affluence settings as potential targets of medical and policy interventions aiming to prevent, reduce, or manage chronic pain among older patients and aging populations.