Table 4.

Relative validity of a self-administered dietary history questionnaire; nutrients corrected for attenuation and energy (Pearson correlation)⁸

Nutrients	Correlation recalls versus Q1c	Correlation adjusted for attenuation	Correlation adjusted for energy	Correlation adjusted for energy and attenuation
Energy	0.40	0.43	-	-
Protein	0.29	0.35	0.46	0.56
Carbohydrates	0.42	0.45	0.58	0.64
Fat	0.49	0.55	0.43	0.49
Alcoholb	0.63	0.70	0.65	0.71
Cholesterolb	0.46	0.53	0.54	0.68
Dietary fibre	0.44	0.51	0.61	0.72
Vitamin Cb	0.55	0.63	0.60	0.69
Retinolb	0.33	0.37	0.25	0.29
β-caroteneb	0.63	0.79	0.64	0.81
Vitamin E	0.44	0.49	0.36	0.42
Calcium	0.38	0.42	0.47	0.53
Iron	0.28	0.34	0.49	0.63
Energy %
alcohol	0.78	0.86	-	-
Protein	0.66	0.67	-	-
carbohydrates	0.59	0.74	-	-
Fat	0.50	0.60	-	-

^a95% confidence intervals for N= 110 are: −0.09, 0.28 for r = 0.1; 0.01, 0.37 for r = 0.2; 0.12, 0.46 for r = 0.3; 0.27, 0.54 for r = 0.4; 0.35, 0.63 for r = 0.5; 0.46, 0.71 for r = 0.6; 0.59, 0.79 for r = 0.7; 0.72, 0.86 for r = 0.8; 0.86, 0.93 for r = 0.9.

^bLog transformed data.

^cQ1 = First questionnaire.