Table 3.

Reproducibility and relative validity of a self-administered dietary history questionnaire for food groups and nutrients⁸

Food groupsb	Reproducibility	Relative validity	Nutrientsc	Reproducibility	Relative validity
	Q1e versus Q2f	24h recall		Q1 versus Q2	24h recall
	n = 105	n = 115		n = 105	n = 115
Potatoes	0.67	0.52	Energy	0.70	0.40
Vegetables	0.64	0.50	Protein	0.69	0.29
Legumes	0.63	0.25	Carbohydrates	0.59	0.42
Fruits	0.59	0.44	Fat	0.73	0.49
Dairy products	0.73	0.67	Alcohold	0.68	0.63
Cereals	0.61	0.56	Cholesterold	0.65	0.46
Meat	0.64	0.43	Dietary fibre	0.59	0.44
Fish	0.51	0.39	Vitamin Cd	0.73	0.55
Eggs	0.57	0.40	Retinold	0.66	0.33
Fats	0.74	0.58	Carotened	0.66	0.63
Sugar and sweets	0.69	0.62	Vitamin Ed	0.54	0.44
Cakes	0.50	0.43	Calcium	0.75	0.38
Non-alcoholic beverages	0.61	0.55	Iron	0.62	0.28
Alcoholic beverages	0.69	0.71	Energy, no alcohol	0.71	0.40
Seasoning and sauces	0.40	0.12	Energy % from		0.78
			alcohol	0.75
Soups	0.67	0.41	protein	0.60	0.66
Mixed dishes	0.62	0.10	carbohydrates	0.69	0.59
			fat	0.62	0.50

^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.

^bFor food groups a Spearman correlation is used.

^cFor nutrients a Pearson correlation is used.

^dLog transformed data.

^eQ1 = first questionnaire.

^fQ2 = second questionnaire.