Use of a food frequency questionnaire to assess diets of Jamaican adults: validation and correlation with biomarkers

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,.

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