Skip to main content

Table 3 Reproducibility study: Median daily food intakes, correlation coefficients and the agreement between FFQ1and FFQ2 in 112 lactating mothers

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

Food groups Intake value
Median (P25, P75)
p –valuec Correlation coefficient Agreement
Percentage classified in
FFQ1a FFQ2b rsd rie Same quartile Same or adjacent quartile Extreme quartile
Cereals and cereal products (g/day) 145 (108,185) 153 (126,192) 0.10 0.41** 0.48** 22.1 55.7 30.1
Potatoes (g/day) 15 (1.5,35.5) 20 (1.5,40) 0.56 0.38** 0.57** 31.0 70.8 10.6
Coarse cereals (g/day) 15 (1,32.5) 15 (3,26) 0.47 0.38** 0.59** 27.4 64.6 10.6
Vegetables (g/day) 310 (201,416) 295 (207,434) 0.92 0.47** 0.64** 30.1 60.2 13.3
Fruits (g/day) 310 (205,430) 305 (227,391) 0.79 0.45** 0.64** 26.5 64.6 15.0
Meat (g/day) 100 (63,140) 80 (57,108) 0.008 0.50** 0.61** 21.2 63.7 9.7
Poultry (g/day) 60 (40,80) 60 (40,79) 0.83 0.68** 0.87** 20.4 67.3 10.6
Aquatic products (g/day) 45 (30,93) 40 (27,73) 0.25 0.42** 0.50** 27.4 66.3 13.3
Eggs (g/day) 60 (49,72) 58 (50,77) 0.59 0.61** 0.69** 11.5 50.4 17.7
Beans and legume products (g/day) 9 (3,17) 10 (5,20) 0.26 0.43** 0.65** 23.0 60.2 9.7
Milk and milk products (g/day) 134 (0,234) 167 (42,201) 0.94 0.39** 0.55** 23.9 65.5 15.0
Nuts (g/day) 8 (0,20) 10 (0,20) 0.39 0.34** 0.57** 27.4 61.9 15.0
  1. a FFQ1: the first food frequency questionnaire which was conducted at 60–65 days postpartum
  2. b FFQ2: the second food frequency questionnaire which was conducted at 5 weeks later during follow-ups
  3. c p-value: Wilcoxon signed rank test
  4. d rs: Spearman rank correlation coefficients
  5. e ri: Intra-class correlation coefficients
  6. *p < 0.05, **p < 0.01