Validity and reliability of a simplified food frequency questionnaire: A cross sectional study among physical health examination adults in southwest region of China

Abstract

Background: In China, many people are suitable for participating in regular physical examination for prevention. Some simplified food frequency questionnaires have been designed and used. However, the accuracy of questionnaire is absent. This study aimed to examine the reliability and validity of simplified food frequency questionnaire (SFFQ) used among physical examination adults in southwest region of China.Methods: This was a cross-sectional study conducted among physical health examination adults in Southwest region of China. A total of 239 participants aged 20-65 were included from February 2019 to June 2019. The performance of SFFQ was evaluated by means of a three-day 24-hour dietary record (3R24). The relative validity and agreement was assessed by Pearson`s correlation and intra-class correlation coefficients (ICC), respectively. Results: The median energy-adjusted ICC of food groups between SFFQ2 and SFFQ1 was 0.59 (range: 0.49-0.73) and the ICC of nutrients was 0.47(range: 0.39-0.76). The Pearson correlation showed a validity between SFFQ1 and 3R24, which ranged from -0.086 to 0.93 for food and 0.21 to 0.71 for nutrition, respectively. The energy-adjustment slightly increased the correlation coefficients.Conclusions: The reliability and validity of SFFQ was acceptable. It could be an appropriate dietary assessment tool for future epidemiological studies among physical health examination adults in southwest China.Trial registration:CHiCTR, ChiCTR1900020934, Registered 22 January 2019, http://www.chictr.org.cn/edit.aspx?pid=35414&htm=4.