TABLE 2.

Cognitive z-scores and 95% confidence intervals (CIs) by quartile of serum cotinine level.

	Quartile 1 ≤0.01 ng/ml	Quartile 2 0.01 < cotinine ≤ 0.02 ng/ml	Quartile 3 0.02 < cotinine ≤ 0.04 ng/ml	Quartile 4 >0.04 ng/ml
CERAD W-L immediate recall	0.09 (−1.85, 2.03)	−0.03 (−2.07, 2.01)	0.00 (−1.92, 1.91)	−0.09 (−2.10, 1.92)
CERAD W-L delayed recall	0.10 (−1.85, 2.05)	−0.08 (−2.20, 2.04)	0.03 (−1.92, 1.97)	−0.05 (−1.98, 1.88)
Animal fluency test	0.13 (−1.81, 2.08)	0.04 (−2.08, 2.16)	−0.01 (−1.81, 1.79)	−0.18 (−2.07, 1.71)
Digit symbol substitution test	0.21 (−1.75, 2.17)	0.03 (−1.94, 1.99)	0.02 (−2.02, 2.06)	−0.19 (−2.03, 1.66)
Global cognition	0.13 (−1.82, 2.07)	−0.04 (−2.12, 2.04)	−0.03 (−1.93, 1.88)	−0.21 (−2.07, 1.65)