Table 2.

Associations of sociodemographic, lifestyle, and sampling factors with plasma 8-OHdG and F2-isoprostanes.

	8-OHdG				F2-isoprostanes
	Univariate		Multivariable		Univariate		Multivariable
	N = 1114		N = 1104		N = 1025		N = 1017
	β	p	β	p	β	p	β	p
Sociodemographics
Age (years)	0.16	<0.001	0.16	<0.001	0.07	0.018	0.07	0.043
Female sex (male is ref.)	−0.16	<0.001	−0.14	<0.001	0.13	<0.001	0.15	<0.001
Education (years)	−0.04	0.154	−0.02	0.558	−0.09	0.002	−0.10	0.001
North-European ancestry (“NO” is ref.)	0.05	0.128	0.05	0.129	0.00	0.915	−0.01	0.738
Lifestyle
Smoking
Ref. nonsmokers	Ref.		Ref.		Ref.		Ref.
<10 cig/day	0.08	0.010	0.05	0.120	0.04	0.191	0.02	0.546
≥10 cig/day	0.11	<0.001	0.05	0.398	0.02	0.497	−0.07	0.098
Plasma cotinine (ng/mL)	0.12	<0.001	0.09	0.034	0.07	0.013	0.09	0.027
Alcohol
ref. < 1 unit/wk	Ref.		Ref.		Ref.		Ref.
♂ ≤ 21/♀ ≤ 14 units/wk	0.04	0.233	0.00	0.921	0.01	0.818	0.06	0.094
♂ > 21/♀ > 14 units/wk	0.03	0.326	−0.02	0.553	0.12	<0.001	0.13	<0.001
Body mass index (kg/m2)	0.04	0.160	−0.02	0.594	0.06	0.053	0.05	0.099
Physical activity (MET-min/wk)	0.00	0.925	0.00	0.926	0.00	0.882	−0.02	0.440
Supplement use (“NON user” is ref.)	0.02	0.456	0.01	0.848	−0.05	0.076	−0.07	0.020
Sampling variables
Season of sample collection
Ref. winter (Dec.–Feb.)	Ref.		Ref.		Ref.		Ref.
Spring (Mar.–May)	0.00	0.997	0.02	0.674	0.10	0.005	0.11	0.002
Summer (Jun.–Aug.)	−0.02	0.606	0.01	0.884	0.05	0.153	0.07	0.043
Autumn (Sep.–Nov.)	−0.01	0.877	0.01	0.729	−0.03	0.493	−0.01	0.776
Fasting prior to sample collection (“NO” is ref.)	−0.08	0.010	−0.06	0.034	−0.06	0.050	−0.07	0.014

8-OHdG and F2-isoprostanes were log transformed for analysis. All analyses are adjusted for research site. Results are reported as standardized regression coefficients. Cig: cigarettes; kg: kilogram; m²: meters squared; MET: metabolic equivalent of task; min: minutes; ref.: reference; Wk: week.