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Table 4 Reproducibility study: Median daily energy and nutrient intakes, correlation coefficients and 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

Energy and nutrients 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
Energy (kcal/day) 2006.2 (1632.9, 2229.3) 2009.4 (1635.7, 2231.4) 0.91 0.59** 0.70** 65.5 84.1 6.2
Protein (g/day) 85.4 (69.1, 103.9) 84.5 (68.1, 99.5) 0.68 0.61** 0.55** 46.9 82.3 5.3
Fat (g/day) 88.3 (73.1, 98.7) 83.0 (70.9, 95.5) 0.19 0.44** 0.34** 43.4 83.2 7.1
Total Fatty acid (g/d) 68.6 (47.7, 86.5) 61.5 (43.9, 82.7) 0.17 0.43** 0.45** 43.7 82.2 7.2
SFA (g/d) f 14.5 (8.0, 22.7) 11.6 (7.2, 17.6) 0.06 0.41** 0.33* 48.2 80.4 8.1
MUFA (g/d) g 25.3 (15.0, 36.2) 21.9 (13.4, 31.9) 0.11 0.39** 0.38** 44.6 81.3 8.1
PUFA (g/d) h 11.9 (7.0, 17.7) 10.4 (6.6, 17.0) 0.73 0.43** 0.41** 46.4 83.2 6.3
n-3 PUFA (g/d) i 0.06 (0.04, 0.10) 0.06 (0.04, 0.09) 0.14 0.35** 0.28* 41.9 76.9 8.1
n-6 PUFA (g/d) j 0.80 (0.50, 1.14) 0.76 (0.50, 1.01) 0.17 0.29** 0.33* 51.8 78.8 10.8
Carbohydrate (g/d) 212.5 (171.6, 250.8) 216.4 (170.4, 260.4) 0.41 0.50** 0.55** 45.1 83.2 5.3
Dietary fiber (g/d) 15.0 (10.7, 20.5) 14.8 (10.9, 19.8) 0.85 0.33** 0.36** 43.6 77.9 8.8
Vitamin A (μgRAE/day) k 857.2 (597.3, 1330.3) 721.5 (559.2, 976.9) 0.04 0.25** 0.27* 41.6 73.5 10.6
Thiamin (mg/day) 0.9 (0.7, 1.1) 0.9 (0.7, 1.1) 0.69 0.53** 0.47** 51.3 84.9 4.4
Riboflavin (mg/day) 1.3 (1.1, 1.7) 1.3 (1.1, 1.5) 0.17 0.42** 0.29** 46.0 74.3 8.0
Niacin (mg/day) 20.3 (15.9, 26.9) 20.0 (15.3, 24.5) 0.21 0.57** 0.50** 50.4 82.3 2.7
Vitamin C (mg/day) 135.4 (78.6, 194.1) 139.6 (96.6, 194.0) 0.67 0.31** 0.43** 38.9 75.2 8.0
Vitamin E (mg/day) 34.0 (30.3, 40.6) 35.9 (30.9, 41.9) 0.38 0.30** 0.32** 46.0 77.9 8.0
Calcium (mg/day) 625.4 (501.3, 789.9) 706.0 (542.2, 845.7) 0.13 0.39** 0.53** 38.9 77.0 6.2
Phosphorus (mg/day) 1261.1 (1041.8, 1495.3) 1304.6 (1056.1, 1500.3) 0.68 0.59** 0.52** 45.1 88.5 2.7
Potassium (mg/day) 2555.9 (2105.9, 3258.7) 2568.9 (2126.1, 3298.8) 0.93 0.47** 0.59** 52.2 80.5 3.5
Magnesium (mg/day) 356.5 (286.1, 431.9) 362.5 (289.2, 446.3) 0.59 0.44** 0.50** 43.4 78.8 8.0
Iron (mg/day) 25.1 (20.0, 31.8) 24.9 (20.5, 31.2) 0.77 0.45** 0.32** 51.3 80.5 8.0
Zinc (mg/day) 12.9 (10.6, 15.8) 13.1 (10.5, 15.7) 0.92 0.58** 0.66** 52.2 87.6 4.4
Selenium (μg/day) 58.5 (50.7, 73.2) 58.7 (47.7, 69.9) 0.59 0.26** 0.29* 38.9 75.2 9.7
Copper (mg/day) 2.4 (1.8, 3.0) 2.5 (2.0, 3.1) 0.71 0.48** 0.44** 49.6 78.8 4.4
Manganese (mg/day) 4.9 (4.0, 6.1) 5.2 (4.0, 6.7) 0.23 0.44** 0.48** 46.9 81.4 5.3
  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. f SFA: saturated fatty acid
  7. g MUFA: monounsaturated fatty acid
  8. h PUFA: polyunsaturated fatty acid
  9. I n-3 PUFA: n-3 polyunsaturated fatty acid
  10. j n-6 PUFA: n-6 polyunsaturated fatty acid
  11. k RAE: retinol activity equivalent
  12. *p < 0.05, **p < 0.01