Table 1.

Models Predicting Each Smoking Phenotype Within European Americans in the ARIC Dataset

Exposures	Demographics only	Demographics plus genetic ancestry and PRS
	OR [95% CI]	OR [95% CI]
Ever smoking
Age	1.00 [0.99, 1.01]	1.00 [0.99, 1.01]
Sex—female	0.39 [0.35, 0.42]	0.37 [0.34, 0.41]
PRS—ever smoking		1.37 [1.31, 1.43]
Model prediction	Pseudo R2 = 0.068	Pseudo R2 = 0.107a
Early age of smoking initiation (<18 years)
Age	0.99 [0.98, 1.00]	0.99 [0.98, 1.00]
Sex—female	0.42 [0.38, 0.48]	0.42 [0.37, 0.47]
PRS—age of smoking initiation		0.87 [0.82, 0.92]
Model prediction	Pseudo R2 = 0.056	Pseudo R2 = 0.067b
Heavier smoking (≥21 cigarettes smoked per day)
Age	0.97 [0.96, 0.98]	0.97 [0.96, 0.98]
Sex—female	0.43 [0.38, 0.48]	0.42 [0.37, 0.47]
PRS—cigarettes smoked per day		1.17 [1.11, 1.25]
Model prediction	Pseudo R2 = 0.056	Pseudo R2 = 0.066c
Smoking cessation
Age	0.97 [0.96, 0.98]	0.97 [0.96, 0.98]
Sex—female	2.00 [1.79, 2.24]	2.01 [1.79, 2.25]
PRS—smoking cessation		1.24 [1.17, 1.32]
Model prediction	Pseudo R2 = 0.047	Pseudo R2 = 0.069d

ARIC = Atherosclerosis Risk in Communities, CI = confidence interval, OR = odds ratio, PRS = polygenic risk score. The reference for sex is male. The PRSs are in z-scores. The reference group for each PRS is a z-score of 0. Each OR represents a 1 standard deviation increase in PRS z-score.

^aThe Χ² statistic from the likelihood ratio test when comparing to the demographics only model is 264.80 with 11 degrees of freedom and a corresponding p value of <0.0001.

^bThe Χ² statistic from the likelihood ratio test when comparing to the demographics only model is 44.19 with 11 degrees of freedom and a corresponding p value of <0.0001.

^cThe Χ² statistic from the likelihood ratio test when comparing to the demographics only model is 38.11 with 11 degrees of freedom and a corresponding p value of 0.0001.

^dThe Χ² statistic from the likelihood ratio test when comparing to the demographics only model is 85.21 with 11 degrees of freedom and a corresponding p value of <0.0001.