Objectively-measured movement behaviors, systemic low-grade inflammation, and plasma neurofilament light chain in older adults: a population-based study

Abstract

Background Evidence has linked self-reported sedentary behavior (SB) and physical activity (PA) with cognitive impairment; however, the underlying neuropathological mechanisms are poorly understood. We examined the dose-response associations of the accelerometer-measured daily SB and PA time with plasma neurofilament light chain (NfL) among older adults and the role of systemic low-grade inflammation in the associations. Methods This population-based study included 1,029 dementia-free older adults (age ≥ 60 years, 59.48% women) who undertook the ActiGraph substudy (March 2018-December 2020) in MIND-China. Plasma NfL and serum cytokines were measured on SIMOA and MSD platforms, respectively. Movement parameters were assessed with an accelerometer. Data were analyzed using the restricted cubic splines, general linear, and mediation models. Results There were J-shaped associations of daily SB and PA time with plasma NfL concentration, such that more daily SB time or less daily light-intensity physical activity (LPA) and moderate-to-vigorous-intensity physical activity (MVPA) time were significantly associated with increased plasma NfL only when SB time ≥ 8.00 hours/day or LPA time < 5.00 hours/day or MVPA time < 2.00 hours/day. Furthermore, more daily SB time or less daily LPA and MVPA time was significantly associated with higher serum inflammation scores (P < 0.05). Finally, serum biomarkers of low-grade inflammation could account for 15–19% of the associations between movement behaviors and plasma NfL level. Conclusions More daily SB and less PA time are associated with peripheral biomarker for neurodegeneration and systemic low-grade inflammation in older adults. The association of movement behaviors with neurodegeneration is partially mediated by systemic low-grade inflammation.