Table 7. Comparison of reproducibility of self-administered food frequency questionnaires developed for epidemiologic studies in Japan: results expressed by correlation coefficients for energy and 8 selected nutrients.

Study	Shimizu et al.		Egami et al.	Imaeda et al.	Present study
Type of correlation	IC	IC	PC	SC	SC	SC
Sex	Men	Women	Both	Women	Men	Women
n	58	59	86	84	101	108
Crude intakes
Energy	0.53	0.30	0.58	0.78	0.52	0.67
Protein	0.54	0.33	0.52	0.74	0.59	0.69
Fat	0.65	0.45	0.58	0.71	0.53	0.67
Carbohydrate	0.45	0.24	0.58	0.73	0.66	0.66
Calcium	0.67	0.50	0.76	0.73	0.63	0.67
Carotene	0.49	0.60	0.53	0.62	0.64	0.73
Vitamin C	0.51	0.18	0.66	0.65	0.51	0.56
Sodium	0.55	0.32	---	---	0.70	0.58
Cholesterol	0.67	0.48	0.41	0.80	0.56	0.69
Median	0.54	0.33	0.58	0.73	0.59	0.67
Energy-adjusted intakes*
Protein	0.52	0.50	0.65	0.56	0.47	0.32
Fat	0.61	0.57	0.74	0.52	0.47	0.52
Carbohydrate	0.65	0.49	0.53	0.51	0.45	0.50
Calcium	0.78	0.67	0.82	0.70	0.49	0.56
Carotene	0.62	0.58	0.48	0.58	0.49	0.63
Vitamin C	0.64	0.13	0.68	0.56	0.40	0.46
Sodium	0.55	0.48	---	---	0.67	0.49
Cholesterol	0.55	0.36	0.51	0.46	0.51	0.54
Median	0.62	0.50	0.65	0.56	0.48	0.51

Abbreviations: IC=intraclass correlation; PC=Pearson correlation; SC=Spearman correlation.

*Residual method