Table 5

Comparison between biomarker levels and nutrient intakes estimated from the food frequency questionnaire according to quartiles and correlation coefficient between measures

Levels in quartiles on the basis of FFQ

p_trend

Correlation of biomarker with dietary intake^a

Q1

Q2

Q3

Q4

unadjusted r

adjusted ^b r

Cholesterol

Intake from FFQ (mg)

95.3 ± 38.9

179.4 ± 19.9

267.5 ± 30.9

468.9 ± 113.8

< 0.0001

Serum cholesterol (μmol/l)

4.46 ± 1.04

4.63 ± 0.96

4.69 ± 1.09

4.93 ± 1.07

0.020

0.19

0.24

Folate

Intake from FFQ (μg)

427 ± 102

643 ± 52

845 ± 63

1123 ± 138

< 0.0001

Whole blood folate (ng/ml)

92.8 ± 132.1

108.0 ± 120.2

63.5 ± 33.4

94.9 ± 148.7

0.628

0.11 ^ns

0.33

Serum folate (ng/ml)

9.55 ± 5.05

10.95 ± 3.95

11.15 ± 3.74

12.85 ± 5.84

0.009

0.22

0.25

^a With the exception of those indicated with ^ns not significant (p > 0.05), all correlations are significant at p < 0.01.

^b Adjusted for age, energy, BMI, current smoking,.

Jackson et al. Nutrition Journal 2011 10:28   doi:10.1186/1475-2891-10-28