Table 3.

Results of the cross-sectional mediation model examining the mediating role of sleep health on the link between the history of rheumatoid arthritis and the risks of elevated C-reactive protein (CRP) and Interleukin-6 (IL-6)

	M: Sleep Health (0 to 5=poorer)			Y1: Risk of Elevated CRP			Y2: Risk of Elevated IL-6
	B		95% CI	Exp(B)		95% CI	Exp(B)		95% CI
Intercept	−0.16	***	[−0.21, −0.10]	0.32	***	[0.28, 0.36]	0.96		[0.86, 1.07]
X: Rheumatoid Arthritis (Having RA vs. Never had RA)	0.10		[−0.44, 0.64]	5.10	**	[1.84, 14.03]	5.81	*	[1.29, 26.12]
M: Sleep Health (0 to 5=poorer)	--		--	1.15	***	[1.07, 1.25]	1.12	**	[1.04, 1.20]
Age (in years)	0.02	***	[0.02, 0.03]	1.01		[0.99, 1.03]	1.08	***	[1.06, 1.10]
Have any diagnosed sleep disorders (Yes vs. No)	0.41	***	[0.25, 0.57]	0.99		[0.72, 1.38]	1.01		[0.75, 1.36]
BMI (kg/m2)	0.07	***	[0.05, 0.08]	1.08	***	[1.06, 1.11]	1.11	***	[1.08, 1.13]
Smoking status (Yes vs. No)	0.49	**	[0.17, 0.81]	2.69	***	[1.51, 4.79]	2.56	**	[1.40, 4.71]
Antidepressants (Using vs. Not using)	0.27	**	[0.10, 0.44]	1.16		[0.83, 1.63]	1.04		[0.76, 1.42]
Benzodiazepines (Using vs. Not using)	0.13		[−0.11, 0.36]	1.99	**	[1.28, 3.11]	1.12		[0.73, 1.71]
Sedatives/hypnotics (Using vs. Not using)	0.21		[−0.13, 0.54]	0.87		[0.41, 1.82]	0.73		[0.39, 1.36]
Sleep medications (Using vs. Not using)	0.27	**	[0.10, 0.43]	0.69	*	[0.48, 0.98]	0.95		[0.70, 1.29]
NSAIDs1 (Using vs. Not using)	0.14	*	[0.03, 0.25]	0.93		[0.75, 1.16]	0.82	†	[0.67, 1.00]
Corticosteroids (Using vs. Not using)	0.11		[−0.05, 0.27]	1.38	*	[1.02, 1.86]	1.80	***	[1.35, 2.43]
Co-morbidities2 (Yes vs. No)	0.04		[−0.07, 0.16]	1.11		[0.88, 1.40]	1.06		[0.86, 1.31]
	R2 = 0.09			-2LL = 2827.24			-2LL = 3337.99
	F= 20.41***			Model LL = 108.25			Model LL = 212.31

Note. N=2562 older men; 2561 and 2560 observations were used in the models predicting CRP and IL-6, respectively, due to missing values in the variables.

X: predictor, M: mediator, Y: outcome.

¹Nonsteroidal anti-inflammatory drugs.

²Co-morbidities were defined by having two or more diseases in 19 conditions including osteoarthritis and rheumatoid arthritis.

^†p < .10,

^*p < .05,

^**p < .01,

^***p < .001.