Table 2.

Association of baseline NFL with clinical assessment scores over 10 years, in patients with PD categorized into tertiles of NFL

Clinical assessments	Main effecta β (95% CI)	P	Interaction with timea β (95% CI)	P
MMSEb
Overall NFLc	−0.05 (−3.17 to 3.08)	0.977	−0.77 (−1.36 to −0.19)	0.010
Tertiles of NFL
Lowest NFL	Ref		Ref
Middle NFL	−0.98 (−6.69 to 4.74)	0.738	−1.01 (−2.19 to 0.16)	0.091
Highest NFL	−0.88 (−7.50 to 5.75)	0.795	−1.42 (−2.64 to 0.21)	0.022
UPDRS
Overall NFLc	2.25 (0.00 to 4.50)	0.050	0.21 (−0.19 to 0.61)	0.296

Bold values are statistically significant p < 0.05. Models are adjusted for age at baseline and sex. Education was included as a covariate for the MMSE model. NFL cut-offs for tertile categorization: Lowest < 13.1 pg/mL; Middle 13.1–20.5 pg/mL; Highest > 20.5 pg/mL.

MMSE mini-mental state examination, NFL neurofilament light chain, UPDRS III Unified Parkinson Disease Rating Scale Part III, CI confidence interval, Ref reference.

^aMain effect indicates the effect of NFL levels on the intercept and the interaction with time indicates the effect of NFL levels on slope (annual change per year) of the model.

^bMMSE and NFL were transformed as described in the “Methods” section.

^cOverall NFL indicates that NFL was included in the model as a continuous variable.