Table 2. Interactions of Physical Activity With Time by NfL Concentration^a.

Interaction	Low NfLb				High NfLc
	Participants, No.	Observations, No.	β (SE)	P value	Participants, No.	Observations, No.	β (SE)	P value
Global cognition
Medium physical activity × timed	619	1976	0.020 (0.010)	.04	541	1533	0.009 (0.014)	.51
High physical activity × timee			0.014 (0.010)	.15			0.027 (0.015)	.08
Episodic memory
Medium physical activity × timed	616	1957	0.013 (0.013)	.32	535	1503	−0.002 (0.017)	.90
High physical activity × timee			0.007 (0.013)	.58			0.039 (0.018)	.03
Perceptual speed
Medium physical activity × timed	611	1937	0.024 (0.011)	.03	510	1436	0.017 (0.013)	.21
High physical activity × timee			0.022 (0.011)	.05			0.027 (0.014)	.06
MMSE score
Medium physical activity × timed	619	1975	0.027 (0.011)	.02	542	1534	0.026 (0.018)	.15
High physical activity × timee			0.020 (0.011)	.07			0.015 (0.019)	.45

Abbreviations: MMSE, Mini-Mental State Examination; NfL, neurofilament light chain.

^a All regression models were adjusted for age, race, sex, educational level, chronic conditions, and presence of the apolipoprotein E ε4 allele.

^b Serum NfL concentration of 25.5 pg/mL or less.

^c Serum NfL concentration greater than 25.5 pg/mL.

^d Less than 150 minutes per week.

^e At least 150 minutes per week.