Effect of seasonality on the estimated mean value of nutrients and ranking ability of a self-administered diet history questionnaire

Table 5 Pearson correlation coefficients between 16-day DR and DHQ administered in each season for estimated crude energy and energy-adjusted nutrient intake among 92 women

	Women (n = 92)
	Fall^*	Winter^*	Spring^*	Summer^*
Energy	0.30	0.26	0.19	0.28
Protein	0.45	0.37	0.40	0.28
Fat	0.59	0.62	0.30**	0.36*
Saturated fat	0.70	0.68	0.47**	0.46**
Monounsaturated fat	0.55	0.64	0.26**	0.33*
Polyunsaturated fat	0.35	0.41	0.22	0.29
n-3 Polyunsaturated fat	0.23	0.22	0.24	0.19
n-6 Polyunsaturated fat	0.44	0.50	0.27	0.35
Marine-origin n-3 polyunsaturated fat^†	0.39	0.43	0.41	0.31
Eicosapentaenoic acid	0.42	0.45	0.47	0.39
Docosahexaenoic acid	0.36	0.40	0.36	0.27
α-Linolenic acid	0.23	0.29	0.22	0.23
Cholesterol	0.35	0.30	0.34	0.33
Carbohydrate	0.62	0.63	0.43*	0.54
Total dietary fiber	0.69	0.66	0.61	0.60
Soluble dietary fiber	0.62	0.55	0.52	0.54
Insoluble dietary fiber	0.70	0.69	0.62	0.59
Alcohol	0.85	0.89	0.79	0.68***
Retinol	0.43	0.40	0.31	0.41
Vitamin A (retinol equivalent)^‡	0.47	0.35	0.34	0.35
α-carotene	0.47	0.31	0.34	0.40
β-Carotene	0.58	0.43	0.55	0.53
β-Carotene equivalent^§	0.58	0.47	0.57	0.54
Cryptoxanthin	0.47	0.56	0.36	0.33
α-Tocopherol	0.39	0.42	0.40	0.29
Vitamin K	0.47	0.42	0.59	0.47
Thiamin	0.31	0.35	0.14	0.02*
Riboflavin	0.50	0.44	0.42	0.27*
Niacin	0.52	0.39	0.39	0.31*
Vitamin B6	0.60	0.58	0.44	0.42*
Vitamin B12	0.46	0.33	0.33	0.26
Folate	0.54	0.49	0.50	0.42
Pantothenic acid	0.57	0.60	0.60	0.51
Vitamin C	0.51	0.55	0.50	0.41
Sodium	0.38	0.35	0.30	0.36
Potassium	0.49	0.51	0.52	0.49
Calcium	0.50	0.56	0.67**	0.54
Magnesium	0.60	0.59	0.51	0.52
Phosphorus	0.44	0.45	0.52	0.45
Iron	0.63	0.50	0.48	0.36**
Zinc	0.50	0.54	0.42	0.35
Copper	0.67	0.66	0.57	0.50*
Manganese	0.47	0.64*	0.59	0.47

Abbreviations: DR = semi-weighed 16-day dietary records; DHQ = self-administered diet history questionnaire.
All variables were log-transformed before analysis.
^*The periods in which the DHQs were administered in each season were as follows: Fall = November or December 2002, Winter = February 2003, Spring = May 2003, Summer = August or September 2003.
^†Sum of eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid.
^‡Sum of retinol, β-carotene/12, α-carotene/24, and cryptoxanthin/24.
^§Sum of β-carotene, α-carotene/2, and cryptoxanthin/2.
Significant difference between correlation coefficients fall and other seasons: *P < 0.05, **P < 0.01, ***P < 0.001(Meng-Rosenthal-Rubin method).

ISSN: 1475-2891