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

Table 4 Pearson correlation coefficients between the 16-day DR and DHQ administered in each season for estimated crude energy and energy-adjusted nutrient intake among 92 men

	Men (n = 92)
	Fall^*	Winter^*	Spring^*	Summer^*
Energy	0.40	0.40	0.31	0.36
Protein	0.34	0.47	0.46	0.40
Fat	0.53	0.59	0.27*	0.43
Saturated fat	0.56	0.68	0.40	0.47
Monounsaturated fat	0.58	0.61	0.25**	0.44
Polyunsaturated fat	0.48	0.43	0.21**	0.33
n-3 Polyunsaturated fat	0.32	0.17	0.19	0.28
n-6 Polyunsaturated fat	0.50	0.49	0.24**	0.35
Marine-origin n-3 polyunsaturated fat^†	0.36	0.34	0.40	0.36
Eicosapentaenoic acid	0.36	0.34	0.41	0.38
Docosahexaenoic acid	0.36	0.33	0.37	0.33
α-Linolenic acid	0.39	0.37	0.11*	0.30
Cholesterol	0.46	0.55	0.19*	0.41
Carbohydrate	0.64	0.63	0.52	0.58
Total dietary fiber	0.72	0.73	0.69	0.60
Soluble dietary fiber	0.64	0.66	0.64	0.60
Insoluble dietary fiber	0.72	0.73	0.68	0.59*
Alcohol	0.82	0.87	0.65***	0.66**
Retinol	0.19	0.32	0.23	0.18
Vitamin A(retinol equivalent)^‡	0.20	0.30	0.25	0.25
α-Carotene	0.10	0.24	0.18	0.30
β-Carotene	0.36	0.47	0.49	0.52
β-Carotene equivalent^§	0.38	0.48	0.46	0.51
Cryptoxanthin	0.54	0.46	0.35	0.21**
α-Tocopherol	0.42	0.37	0.29	0.27
Vitamin K	0.46	0.52	0.67**	0.54
Thiamin	0.36	0.31	0.20	0.21
Riboflavin	0.38	0.39	0.49	0.48
Niacin	0.43	0.45	0.40	0.44
Vitamin B6	0.54	0.51	0.35	0.40
Vitamin B12	0.38	0.38	0.32	0.36
Folate	0.35	0.46	0.39	0.27
Pantothenic acid	0.57	0.64	0.58	0.49
Vitamin C	0.49	0.52	0.44	0.47
Sodium	0.33	0.36	0.32	0.32
Potassium	0.53	0.56	0.62	0.57
Calcium	0.66	0.67	0.72	0.69
Magnesium	0.57	0.48	0.56	0.51
Phosphorus	0.53	0.51	0.59	0.55
Iron	0.49	0.56	0.50	0.37
Zinc	0.33	0.51*	0.40	0.35
Copper	0.59	0.63	0.46	0.46
Manganese	0.49	0.48	0.53	0.40

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