Table 3.

Multivariable-adjusted^* mean difference in global cognitive performance^† (1995–2001) by quartiles of plasma carotenoids and tocopherol levels (1989–1990):effect modification by smoking status and multivitamin use

Effect modification with smoking^‡		Mean Difference in Global Score (95% Confidence Interval)

	Cigarette Smoking	1^st Quartile	2^nd Quartile	3^rd Quartile	4^th Quartile

Plasma Carotenoids	None (49%)	0 (REF)	0.14 (−0.05, 0.34)	0.10 (−0.09, 0.29)	0.04 (−0.15, 0.23)
	Ever smoked (51%)	0.06 (−0.12, 0.24)	0.10 (−0.09, 0.29)	0.09 (−0.10, 0.28)	−0.10 (−0.30, 0.10)
					p-interaction=0.23

		1^st Quartile	2^nd Quartile	3^rd Quartile	4^th Quartile

Plasma Tocopherols	None (49%)	0 (REF)	0.00 (−0.19, 0.18)	0.00 (−0.19, 0.20)	0.06 (−0.15, 0.26)
	Ever smoked (51%)	0.01 (−0.17, 0.19) 0.19)	−0.03 (−0.22, 0.15)	−0.08 (−0.28, 0.12)	0.03 (−0.16, 0.22)
					p-interaction=0.84

Effect modification with supplement use at blood draw^‡		Mean Difference in Global Score (95% Confidence Interval)

	Supplement Use	1^st Quartile	2^nd Quartile	3^rd Quartile	4^th Quartile

Plasma Carotenoids	No (50%)	0 (REF)	0.09 (−0.13, 0.32)	0.20 (−0.01, 0.42)	0.10 (−0.13, 0.33)
	Yes (50%)	0.12 (−0.11, 0.34)	0.17 (−0.06, 0.41)	0.14 (−0.10, 0.38)	−0.08 (−0.29, 0.14)
					p-interaction=0.04

		1^st Quartile	2^nd Quartile	3^rd Quartile	4^th Quartile

Plasma Tocopherols	No (50%)	0 (REF)	−0.01 (−0.21, 0.18)	−0.08 (−0.30, 0.14)	−0.05 (−0.33, 0.23)
	Yes (50%)	−0.09 (−0.35, 0.17)	−0.08 (−0.30, 0.15)	−0.16 (−0.38, 0.05)	0.02 (−0.18, 0.21)
					p-interaction=0.27

Adjusted for the same covariates in the footnotes to Table 2

^†

Global score is an average of the z-scores of six tests: TICS, East Boston Immediate recall, East Boston Delayed recall, 10 words list Delayed recall, verbal / category function, digit backwards

^‡

Current use of multivitamins, vitamin E or vitamin A as of the biennial questionnaires immediately prior to blood draw