Validity and reproducibility of a semi‐quantitative food frequency questionnaire for Iranian adults

Aim To validate a semi‐quantitative food frequency questionnaire (SFFQ) and assess the dietary intake of Iranian adults. Methods This study was conducted among 113 healthy adults in Iran. We administered twelve 24‐hour dietary recalls (24DRs) during a year as a reference method. The 165‐item SFFQ was administered twice, along with the first and last 24DRs. To examine validity and reproducibility of SFFQ, the correlation coefficients (r) and de‐attenuated correlation coefficients and intra‐class correlation coefficient (ICC) between 24DRs and SFFQ were calculated. The Bland‐Altman method was used to assess agreement between the two methods. Results De‐attenuated correlations varied from 0.42 (polyunsaturated fatty acids) to 0.62 (energy) (all P