Comparative Analysis of Biological Aging and Inflammatory Profiles in Adult Spinal Deformity Patients Between Japan and the United States: A Correlative Study.

Abstract

Study designRetrospective matched cohort study.ObjectiveUnderstanding biological aging in adult spinal deformity (ASD) across different populations offers insights into its impact on aging and potential interventions.Summary of background dataASD significantly impacts physiological health and may accelerate biological aging. Understanding biological aging in ASDs across different populations offers insights into ASD's impact on aging and potential interventions.Materials and methodsASDs and norms from Japan (JP) and the U.S. (US) were included. The US norm consisted of 8,751 adults from NHNES 2017-20; the JP norm comprised 10,205 adults from health check-ups between 2020-23. Age- and gender-matched norm cohorts of 6,584 pairs (JP vs. US) were established (age: 55±13 vs. 55±14 y; female: 49 vs. 50%). ASD were age-, race- and gender-matched to norm individuals in JP (159 pairs) and the US (132 pairs). Additionally, 81 pairs of ASDs from JP and US were selected for cross-country comparisons.ResultsThe JP was biologically younger than the US (PhenoAge: mean difference [MD] -6.5±0.3 y; P<0.01). When comparing JP and US Asians, the JP remained biologically younger (MD: -3.1±0.7 y; P<0.01), suggesting lifestyle differences. JP ASDs were biologically older than their norms (MD: 4.2±1.7 y; P=0.02), indicating accelerated aging. However, no significant difference was observed between ASDs and the norms in the US. No significant difference in PhenoAge was found between JP and US ASDs (57.9±18.4 vs. 59.6±17.6 y; P=0.56). ASDs in both countries exhibited higher systemic inflammation, with US ASDs showing particularly elevated CRP levels (US ASD vs. norm: 2.8±8.5 vs. 0.4±0.8 mg/dL; P<0.01; JP: 0.5±1.3 vs. 0.2±0.4 mg/dL; P<0.01).ConclusionsJP are biologically younger than their US counterparts, potentially due to lifestyle factors. JP ASDs exhibit accelerated biological aging compared to the norm cohort, highlighting the impact of ASD on aging. Elevated systemic inflammation in ASDs underscores the importance of managing inflammatory processes.