Reproducibility and validity of a 45 item food-frequency questionnaire for inuit in Greenland.

Since 1993, dietary assessment has been carried out in Greenland as part of recurrent population health surveys. In preparation for the next survey in 2024, 91 participants from the survey in 2018 were selected for a validation study of the Food Frequency Questionnaire (FFQ). The 91 participants were reinterviewed 38-50 months after the first FFQ and invited to complete a food diary. As part of the 2018 survey, blood was analysed for mercury. The food diary was completed by 65 participants. The agreement between the two FFQ interviews was very good for macronutrients and fatty acids ( p  > 0.20), whereas the calculated intake of mercury was 22% higher in the second FFQ ( p  = 0.04) due to a higher intake of whale meat and muktuk (whale skin). The agreement between the second FFQ and the food diary was good for local food, imported meat and cakes/sweets/snacks but fruit and vegetables, dairy products, beverages and added sugar were significantly underreported in the food diary. Food items not included in the FFQ were identified from the food diaries. The correlation between the intake of marine mammals and blood mercury was moderate (Spearman's rho = 0.41-0.50; p  < 0.0001). The results will inspire future dietary studies in the circumpolar North.