Table 4.

Associations of smoking status and the methylation-based smoking index with the frailty index in the validation panel, with and without mutual adjustment for the 2 smoking indicators^a.

		Model including smoking status only			Model including smoking index only				Model including both smoking indicators
Smoking indicators		Estimate	SEb	P-value	Estimate	SE b	P-value	Estimate		SE b	P-value
Smoking status	Never smoker	Ref						Ref
	Former smoker	0.019	0.018	0.293				−0.010		0.019	0.610
	Current smoker	0.037	0.015	0.013				0.023		0.015	0.116
Smoking index	1st Quartile				Ref			Ref
	2nd Quartile				0.033	0.017	0.048	0.034		0.017	0.043
	3rd Quartile				0.062	0.018	0.0008	0.060		0.019	0.0016
	4th Quartile				0.075	0.019	< 0.0001	0.078		0.020	0.0001

^aAll model controlling for age (years), sex (male/female), and alcohol consumption (abstainer/ low/ intermediate/ high). The models including the smoking index were additionally adjusted for the leucocyte distribution estimated by Houseman algorithm.

^bSE = standard error.