Reproducibility and relative validity of a semi-quantitative food frequency questionnaire for the Chinese lactating mothers

Table 5 Relative validity study: Median daily food intakes, correlation coefficients and agreement between FFQ and 3DR in 112 lactating mothers

Food groups	Intake value Median (P25, P75)		p -value ^c	Correlation coefficient			Agreement
	Intake value Median (P25, P75)			Correlation coefficient			Percentage classified in
	FFQ ^a	3DR ^b		r ^d	r _e-adj ^e	r _de-att ^f	Same quartile	Same or adjacent quartile	Extreme quartile
Cereals and cereal products (g/day)	153 (120, 191)	192 (140, 217)	< 0.01	0.56^**	0.55^**	0.67^**	25.7	62.3	13.3
Potatoes (g/day)	17 (9, 32.5)	15 (1.7, 41)	0.328	0.51^**	0.52^**	0.48^**	19.5	62.9	6.2
Coarse cereals (g/day)	17.5 (6, 28)	13 (2, 39)	0.134	0.40^**	0.37^**	0.38^**	23.9	61.2	8.0
Vegetables (g/day)	303 (215, 421)	294 (207, 410)	< 0.01	0.45^**	0.45^**	0.44^**	31.9	71.7	8.8
Fruits (g/day)	306 (228, 411)	228 (118, 356)	< 0.01	0.38^**	0.37^**	0.42^**	25.7	62.0	15.9
Meat (g/day)	95 (68, 130)	116 (73, 163)	< 0.01	0.41^**	0.39^**	0.50^**	27.5	62.0	8.8
Poultry (g/day)	53 (40, 78)	60 (40, 80)	0.58	0.52^**	0.53^**	0.51^**	26.5	63.7	11.5
Aquatic products (g/day)	52 (34, 79)	43 (25, 69)	0.47	0.41^**	0.32^**	0.47^**	41.6	79.7	9.7
Eggs (g/day)	60 (50, 73)	68 (50, 90)	0.068	0.50^*	0.42^**	0.49^**	43.4	83.2	3.5
Beans and legume products (g/day)	10 (5, 19)	6 (0, 16)	0.214	0.54^*	0.54^**	0.47^**	42.5	83.2	4.4
Milk and milk products (g/day)	130 (69, 201)	83 (0, 194)	0.007	0.43^**	0.42^**	0.34^*	45.1	74.3	8.0
Nuts (g/day)	10 (5, 20)	0 (0, 7.5)	< 0.01	0.32^**	0.26^**	0.36^**	26.5	62.0	12.4

^a FFQ: average of the FFQ1 and the FFQ2
^b 3DR: 3-day dietary records which was completed one week after the FFQ1, including two weekdays and one weekend
^c p -value: Wilcoxon signed rank test
^d r: Spearman rank correlation coefficients
^e r _e-adj: Energy-adjusted correlation coefficient
^f r _de-att: de-attenuated correlation coefficients
^*p < 0.05, ^**p < 0.01

ISSN: 1475-2891