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. Author manuscript; available in PMC: 2016 Jul 1.
Published in final edited form as: Environ Res. 2015 Apr 4;140:127–135. doi: 10.1016/j.envres.2015.03.001

Table 2.

Association between BLL, intakes of vitamin C, zinc and oxidative stress measures1

Models Oxidative stress measures
Isoprostane (ng/ml) 8-OH-dG (ng/ml)
Unadjusted β [95% CI]2 Adjusted β [95% CI]3,4 Unadjusted β [95% CI]2 Adjusted β [95% CI]3,4
Model 1- BLL
BLL, μg/dL 0.08 [−0.001, 0.16]* 0.09 [−0.01, 0.19]* −0.15 [−2.42, 2.11] 1.16 [−1.64, 3.62]
Model 2- vitamin C and zinc intake5
Vitamin C, mg/d
 1st tertile Ref Ref Ref Ref
 2nd tertile 0.02 [−0.42, 0.46] −0.26 [−0.74, 0.21] 7.90 [−4.91, 20.71] −0.79 [−14.36, 12.77]
 3rd tertile −0.15 [−0.59, 0.28] −0.23[−0.69, 0.23] −1.44 [−14.04, 11.15] 0.67 [−12.68, 14.02]
Zinc, mg/d
 1st tertile Ref Ref Ref Ref
 2nd tertile −0.09 [−0.53, 0.34] −0.12 [−0.61, 0.37] −3.85 [−17.16, 9.46] −2.54 [−15.92, 10.84]
 3rd tertile −0.11 [−0.55, 0.33] −0.21 [−0.71, 0.29] −16.39 [−29.21, − 3.58]*** −13.51 [−27.18, 1.88]*
Model 3- main effects: BLL & vitamin C6
BLL 0.09 [0.01, 0.18]** 0.10 [0.01, 0.19]** 0.24 [−2.54, 2.06] 0.37 [−2.26, 3.01]
Vitamin C
 1st tertile Ref Ref Ref Ref
 2nd tertile −0.06 [−0.50, 0.37] −0.27[−0.73, 0.19] 3.85 [−8.47, 6.18] 2.25 [−7.85, 9.33]
 3rd tertile −0.25 [−0.68, 0.19] −0.32[−0.77, 0.12] 0.45 [−11.63, 2.45] 3.16 [−4.27, 14.42]
Model 4- main effects: BLL & zinc7
BLL 0.09 [0.01, 0.17]** 0.09 [0.01, 0.18]** −0.16 [−2.43, 2.11] 0.26 [−2.33, 2.86]
Zinc
 1st tertile Ref Ref Ref Ref
 2nd tertile 0.01 [−0.43, 0.44] 0.20 [−0.27, 0.66] −2.80 [−15.22, 9.61] −2.37 [−13.24, 11.26]
 3rd tertile −0.02 [−0.46, 0.41] 0.10 [−0.37, 0.56] −17.12 [−29.31, − 4.90]*** −14.15 [−23.31, − 0.67]**
1

complete-case analysis

2

results from univariate regression models. Model 1: n= 173 (isoprostane), n= 175 (8-OH-dG); Models 2–4: n= 164 (isoprostane), n= 166 (8-OH-dG)

3

results from multivariate regression models. Model 1: n= 139 (isoprostane), n= 141 (8-OH-dG). Models 2–4: n= 133 (isoprostane), n= 135 (8-OH-dG)

4

models adjusted for family possession of luxury items (≤8 vs >8 items), parental involvement of jobs with potential for metal exposure (not involved vs involved), crowding at home (no. of people/room), mother’s smoking (no vs yes), BMI (kg/m2) and CRP-adjusted ferritin concentration (ng/mL)

5

values adjusted for total energy intake by residual method (Willett et a., 1997)

6

interactions between BLL and vit C were not significant. Models were rerun to test the main effects of BLL and vit C

7

interactions between BLL and zinc were not significant. Models were rerun to test the main effects of BLL and zinc

***

p< 0.01

**

p< 0.05

*

p< 0.1