All dietary assessment methods inevitably introduce measurement errors, which should ideally be considered during data analysis and interpretation. Methodological studies should be conducted to address how well a given assessment method captures dietary intake and to highlight the extent and direction of the measurement error. Within a subgroup of the Hordaland Health Study (HUSK3), we examined the relative validity of a web-based food frequency questionnaire (WebFFQ) by comparing its estimates of mean daily intake of nutrients and foods with estimated mean daily intakes from repeated administrations of 24-hour dietary recall interviews (24-HDRs). Men and women born between 1950 and 1951 were recruited from HUSK3. The participants (n = 67) completed a WebFFQ and three non-consecutive 24-HDRs over the course of a year. Relative validity was assessed using Spearman's rank correlation, crosstab analysis and Bland–Altman plots. Linear regression models were used to compute the calibration coefficients. The estimated correlation coefficients were acceptable or strong for all nutrients and foods except iodine (rs = 0⋅19). The highest correlation coefficient was found for juice (rs = 0⋅71), whereas the lowest correlation coefficient was found for iodine (rs = 0⋅19). Cross-classification by quartiles categorised more than 72 % of the participants into the same or adjacent quartiles using the two methods. Few data points fell outside the limits of agreement in the Bland–Altman plots. Calibration coefficients ranged from 0⋅10 (wholegrain) to 0⋅81 (alcohol). Our findings suggest that the WebFFQ has reasonable ranking abilities for all the included nutrients and foods, except for iodine.

Mild-to-moderate iodine deficiency remains a problem worldwide, including in Norway. Of particular, concern is fertile, pregnant and lactating women. The Norwegian Dairy Council developed a digital iodine-specific dietary screener (I-screener) for the assessment of iodine intake levels but has yet to be validated. The aim was thus to investigate the relative validity of the I-screener by comparing estimates of iodine intake from the I-screener against a single 24-hour recall (24HR) and urinary iodine concentration (UIC) in fertile women. Healthy females were recruited in Bergen in August–December 2021. Six spot-urine samples from six consecutive days were collected into a pooled sample to assess UIC. Each participant completed a single administration of the I-screener and the 24HR. The estimated daily iodine intake from the I-screener was compared with the estimations from the 24HR and UIC. Seventy-two women aged 19–39 completed the study. The median UIC was 76 μg/l. Compared with the 24HR, the I-screener placed 83 % of the participants in the same/adjacent tertial, with a slight agreement between the methods (Cohen's kappa = 0⋅187). The present study shows an acceptable correlation between the I-screener and the 24HR (r = 0⋅318), but not between the I-screener and UIC (r = 0⋅122). Despite its varying iodine estimate abilities, the I-screener may be used as an initial screening tool to rank fertile women on an individual level into deficient inadequate, and sufficient iodine intake. However, due to the relatively high risk of misclassification, further assessment of iodine status should follow.

Purpose The single nutrient approach in nutrition research lacks the ability to account for synergistic relationships between dietary components. Current evidence suggests that diet quality, reflecting overall dietary intake, may influence muscle health. In a community-based observational study in Western Norway, we examined dietary patterns in relation to muscle mass and strength at age 67–70. Methods The current analysis was conducted in men and women of The Hordaland Health Study (HUSK), who participated in both the second (HUSK2) and third study wave (HUSK3). Dietary patterns were extracted by principal component analysis (PCA) on food frequency questionnaire (FFQ) data. Individual dietary pattern scores (DPS) for HUSK2 (age 46–49) and HUSK3 (age 67–70), and overall DPS (oDPS) were calculated. Outcome variables were appendicular skeletal muscle mass (ASMM) and handgrip strength (HGS) measured in HUSK3. The relationships of HUSK3 DPS and oDPS with ASMM and HGS were assessed by multivariate linear regression analysis adjusted for potential confounding factors. Results We identified three distinct dietary patterns, labelled ‘Western’, ‘Healthy’, and ‘Sweets-focused’. A significant positive association was observed between the oDPS for the ‘Healthy’ dietary pattern and ASMM in both men and women at age 67–70. No significant associations were found between HUSK3 DPS or oDPS for any of the identified dietary patterns and HGS in our population. Conclusion Higher oDPS on a dietary pattern predominantly rich in fish, vegetables, nuts and seeds, fruit and berries, and eggs was associated with better ASMM at age 67–70. To establish the influence of diet quality on muscle health, further long-term studies with repeated dietary assessments are warranted.