An estimation of periconceptional under-reporting of dietary energy intake

Background The purpose of this cross-sectional study was to examine periconceptional misreporting of energy intake (EI) using the Willet food frequency questionnaire (WFFQ). Methods Women were recruited in the first trimester. Women completed a semi-quantitative WFFQ. Maternal body composition was measured using eight-electrode bioelectrical impedance analysis. Under-reporters were those whose ratio of EI to their calculated basal metabolic rate fell below the calculated plausible threshold for their physical activity category. Results The mean age was 30.1+5.3 years (n 524). The mean body mass index (BMI) was 25.4+5.6 kg/m2, and 16.6%were obese (BMI 30.0 kg/m2). Under-reported EI was observed in 122 women (23.3%) with no over-reporters in the sample. Under-reporters were younger (P, 0.001), less likely to have a normal BMI (P 0.002) and more likely to be obese (P, 0.001) than plausible reporters. Under-reporters had higher percentage of body-fat and lower percentage of body fat-free mass (P, 0.001), were more likely to be at risk of relative deprivation (P 0.001) and reported a higher percentage of EI from carbohydrate (P 0.02) than plausible reporters. Conclusions Observed differences between under-reporters and plausible reporters suggest that the exclusion of these under-reporters represents an important potential source of bias in obesity research among women in the periconceptional period