Development, reproducibility and validity of the food frequency questionnaire in the Poland arm of the Prospective Urban and Rural Epidemiological (PURE) study

A food frequency questionnaire (FFQ) is the most commonly used method in large epidemiological studies. The validation of an FFQ is essential for specific populations because foods are culture-dependent. The present study aimed to develop an FFQ and evaluate its validity and reproducibility in estimating the intake of nutrients in urban and rural areas of Poland.Adult participants (n = 146) in the Polish arm of the ongoing Prospective Urban and...