Objective: To assess the validity and reliability of an omega-3 fatty acid (FA) food frequency questionnaire (FFQ) and the quantity of omega-3 FA intakes in obese, pregnant women.
Study design: Cross-sectional study.
Subjects: 36 obese (Pre-pregnant BMI ≥ 30), pregnant women were recruited between 24 and 26 weeks gestation from the Greater Cincinnati region.
Methods: We adapted the FFQ developed and evaluated by Ritter-Gooder et al. by adding pictures of portion sizes. To determine the validity, the FFQ was administered by study staff in the clinic or via mail to 36 women. To determine the reliability, a second FFQ was collected from 10 of 36 women two weeks later. The reference method was a 24-hour dietary recall using the standardized interview in Nutrition Data System for Research software obtained from 22 of 36 women. Pearson correlation was used to determined agreement for daily intakes of omega-3 FAs collected from the first administration of FFQ and 24-hour dietary recall. Pearson correlation was also used to assess the test-retest reliability of the FFQ using the two administrations of FFQ.
Results: The mean age of the women was 28 ± 4.8 years. Mean intakes of total omega-3 FAs estimated by the first FFQ and 24-hour dietary recall were 0.98 ± 0.70 g/day and 2.35 ± 1.11 g/day, respectively. The correlation of daily omega-3 FA intakes using the first administration of FFQ and 24-hour dietary recall was r = +0.225 (P > 0.05). The test-retest reliability of the two administrations of FFQ was r = +0.97 (P < 0.01). Fats/oils and nuts/seeds were the top two food sources of omega-3 FAs in this population and provided nearly 40% of omega-3 FA intakes. Forty-two food items contributed 90% of omega-3 FA intakes.
Conclusion: The FFQ yielded excellent reliability, but inadequate validity in obese, pregnant women. Further modification of the FFQ should be made to increase its validity. Both the FFQ and 24-hour food recall showed low intakes of omega-3 FAs in obese, pregnant women. Therefore, this population should increase their consumption of foods rich in omega-3 FAs, especially fish, fish oil supplements or fortified foods rich in eicosapentaenoic Acid (EPA) and docosahexaenoic Acid (DHA).