Can a dietary quality score derived from a short-form FFQ assess dietary quality in UK adult population surveys?

Objective: To devise a measure of diet quality from a short-form FFQ (SFFFQ) for population surveys. To validate the SFFFQ against an extensive FFQ and a 24 h diet recall. Design: Population-based cross-sectional survey. Setting: East Leeds and Bolton in Northern England. Subjects: Adults (n 1999) were randomly selected from lists of those registered with a general practitioner in the study areas, contacted by mail and asked to complete the SFFFQ. Responders were sent a longer FFQ to complete and asked if they would take part in a telephone-based 24 h diet recall. Results: Results from 826 people completing the SFFFQ, 705 completing the FFQ and forty-seven completing the diet recall were included in the analyses. The dietary quality score (DQS), based on fruit, vegetable, oily fish, non-milk extrinsic sugar and fat intakes, showed significant agreement between the SFFFQ and the FFQ (kappa = 0.38, P < 0.001). The DQS for the SFFFQ and the diet recall did not show significant agreement (kappa = 0.04, P = 0.312). A number of single items on the SFFFQ predicted a 'healthy' DQS when calculated from the FFQ. The odds of having a healthy diet were increased by 27% (95% CI 9, 49%, P < 0.001) for an increase in fruit of 1 portion/d and decreased by 67% (95% CI 47, 79 %, P< 0.001) for an increase in crisps of 1 portion/d. Conclusions: The SFFFQ has been shown to be an effective method of assessing diet quality. It provides an important method for determining variations in diet quality within and across different populations.