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Table 6 Intraclass correlation coefficients for food frequency questionnaires completed at the beginning and end of 12 months

From: Use of a food frequency questionnaire to assess diets of Jamaican adults: validation and correlation with biomarkers

  FFQ 1 vs. FFQ 2
  Unadjusted
r(CI)
Energy adjusted
r(CI)
Total Energy (kcal) 0.87 (0.78, 0.92)  
Total Carbohydrate 0.85 (0.76, 0.91) 0.76 (0.61, 0.85)
Protein 0.83 (0.73, 0.90) 0.79 (0.66, 0.87)
Total Fat 0.85 (0.75, 0.90) 0.74 (0.57, 0.84)
   Total Saturated Fat 0.78 (0.65, 0.87) 0.50 (0.18, 0.69)
   Total MUFA 0.82 (0.71, 0.89) 0.79 (0.66, 0.87)
   Total PUFA 0.75 (0.60, 0.80) 0.54 (0.24, 0.71)
Linoleic acid 0.75 (0.59, 0.85) 0.68 (0.48, 0.80)
Linolenic acid 0.73 (0.55, 0.83) 0.55 (0.26, 0.72)
Cholesterol 0.80 (0.67, 0.87) 0.80 (0.67, 0.87)
Calcium 0.85 (0.75, 0.91) 0.79 (0.66, 0.87)
Iron 0.90 (0.84, 0.94) 0.68 (0.47, 0.80)
Retinol 0.73 (0.56, 0.83) 0.74 (0.57, 0.84)
Beta-carotene (ug) 0.71 (0.53, 0.82) 0.75 (0.59, 0.85)
Vitamin E 0.77 (0.56, 0.82) 0.78 (0.58, 0.85)
Folate 0.88 (0.80, 0.92) 0.77 (0.62, 0.86)
Vitamin K 0.72 (0.54, 0.83) 0.72 (0.54, 0.83)
Zinc 0.79 (0.65, 0.87) 0.79 (0.66, 0.87)
Total dietary fiber 0.82 (0.70, 0.90) 0.84 (0.68, 0.90)
Alcohol 0.76 (0.45, 0.89) 0.68 (0.27, 0.86)
  1. a Energy-adjusted correlations between dietary methods as suggested by Willett (1)
  2. b All variables were log-transformed before analysis.