Development of a 20-item food frequency questionnaire to assess a 'prudent' dietary pattern among young women in Southampton.

OBJECTIVE: To develop a short food frequency questionnaire (FFQ) that can be used among young women in Southampton to assess compliance with a prudent dietary pattern characterized by high consumption of wholemeal bread, fruit and vegetables, and low consumption of sugar, white bread, and red and processed meat. METHODS: Diet was assessed using a 100-item interviewer-administered FFQ in 6129 non-pregnant women aged 20-34 years. In total, 94 of these women were re-interviewed 2 years later using the same FFQ. Subsequently, diet was assessed in 378 women attending SureStart Children's Centres in the Nutrition and Well-being Study (NWS) using a 20-item FFQ. The 20 foods included were those that characterized the prudent dietary pattern. RESULTS: The 20-item prudent diet score was highly correlated with the full 100-item score (r=0.94) in the Southampton Women's Survey (SWS). Both scores were correlated with red blood cell folate (r=0.28 for the 100-item score and r=0.25 for the 20-item score). Among the women re-interviewed after 2 years, the change in prudent diet score was correlated with change in red cell folate for both the 20-item (r(S)=0.31) and 100-item scores (r(S)=0.32). In the NWS a strong association between the 20-item prudent diet score and educational attainment (r=0.41) was observed, similar to that seen in the SWS (r=0.47). CONCLUSIONS: The prudent diet pattern describes a robust axis of variation in diet. A 20-item FFQ based on the foods that characterize the prudent diet pattern has clear advantages in terms of time and resources, and is a helpful tool to characterize the diets of young women in Southampton.