Validity and reproducibility of a food frequency questionnaire for pregnant Finnish women

The authors developed a self-administered 181-item food frequency questionn aire (FFQ) to assess dietary intake during pregnancy for Finnish women from August 1995 to July 1996. In the validation study (n=113), the data that w ere collected by using two 5-day food records completed during the eighth m onth of pregnancy were compared with FFQ data. The intake of foods and nutr ients was higher as determined by FFQ than that assessed using food records . Pearson correlation coefficients for nutrients, after adjustment for ener gy, ranged from 0.19 (vitamin E) to 0.70 (thiamin) and, for foods, from 0.0 3 (high-fat milk) to 0.84 (low-fat milk). Energy adjustment improved the co rrelations for nutrients. Correction for attenuation improved correlations for both foods and nutrients. On average, 70% of the foods and 69% of the n utrients fell into the same or adjacent quintiles, according to the FFQ and the food record. In the reproducibility study, 111 women completed the FFQ s twice at a 1-month interval. The intraclass correlation coefficients for nutrients ranged from 0.42 (ethanol) to 0.72 (sucrose, riboflavin, and calc ium), and for foods, they ranged from 0.44 (ice cream) to 0.91 (coffee). Th e authors conclude that the FFQ has an acceptable reproducibility and repre sents a useful tool for categorizing pregnant women according to their diet ary intake.