To evaluate the performance of an FFQ for estimating dietary contributions of NOVA groups to individuals’ diets with a specific focus on ultra-processed foods (UPF) compared with a single 24-h dietary recall (24HR).

All consumed foods and beverages assess with both a 109-item FFQ and a single 24HR were classified into one of four NOVA groups: natural or minimally processed foods (MPF), processed culinary ingredients (PCI), processed foods (PF) and UPF. The contributions of each NOVA group to daily intakes of energy, protein, fat, saturated fat, carbohydrate, fibre and Na were expressed as crude intake, energy-adjusted intake and percentage intake. Mean differences, correlation coefficients and joint classification were calculated for intakes of energy and nutrients from each NOVA group between the FFQ and the 24HR.

The Korea National Health and Nutrition Examination Survey 2016.

Adults aged 19–64 years (n 3189).

The smallest group-mean differences between the two methods were observed in UPF (2–40 %). The greatest average Pearson’s correlation coefficients between the FFQ and 24HR were shown in dietary contributions of UPF (r = 0·22–0·25 for MPF; r = 0·02–0·05 for PCI; r = 0·11–0·18 for PF; r = 0·26–0·30 for UPF). The greatest agreement in quartile classification between the FFQ and the 24HR was observed in dietary contributions of UPF (70·0–71·5 % for MPF; 64·2–68·8 % for PCI; 66·9–69·2 % for PF; 71·8–73·9 % for UPF).

The use of the FFQ for estimating absolute intake of UPF may not be encouraged in its current form, but it still may be used for relative comparisons such as quantile categorisation.

Dietary questionnaires for assessing dietary intakes among populations of individuals aged 80 years or older (the very old) are very limited. We examined the relative validity of forty-three nutrients and twenty-seven food groups estimated by a brief-type self-administered diet history questionnaire (BDHQ) targeting very old Japanese, using semi-weighed dietary records (DR) as a reference.

Between June and August 2012 and between June 2015 and February 2016, a three-day non-consecutive DR (at two-week intervals) and a BDHQ were completed.

Tokyo, the capital prefecture of Japan.

Eighty very old Japanese (thirty-six men and forty-four women) aged 82–94 years.

The median intakes of 40–70 % of the crude and energy-adjusted nutrients estimated by the BDHQ were significantly different from those estimated by the DR. The median Spearman’s correlation coefficient of nutrient intakes between the BDHQ and the DR was 0·39–0·46. About half (48–56 %) of the food groups were significantly different in terms of the median intakes estimated by the BDHQ and the DR in crude and energy-adjusted values. The median Spearman’s correlation coefficient between the BDHQ and the DR was 0·45–0·48.

Acceptable Spearman’s correlations (≥0·3) were obtained for many dietary intakes among the very old Japanese population. The BDHQ is a good candidate for epidemiological studies among very old Japanese, although, for some nutrients and food groups, the difficulty of estimating accurate median intakes is one of the limitations for the tool. Further efforts to enhance the validity of the BDHQ for very old populations are needed.

To assess the relative validity of a new, web-based, self-administered 24 h dietary recall, the R24W, for assessment of energy and nutrient intakes among French Canadians.

Each participant completed a 3d food record (FR) and the R24W on three occasions over a 4-week period. Intakes of energy and of twenty-four selected nutrients assessed by both methods were compared.

Québec City metropolitan area.

Fifty-seven women and fifty men (mean (sd) age: 47·2 (13·3) years).

Equivalent proportions of under-reporters were found with the R24W (15·0%) and the FR (23·4%). Mean (sd) energy intake from the R24W was 7·2% higher than that from the FR (10 857 (3184) kJ/d (2595 (761) kcal/d) v. 10 075 (2971) kJ/d (2408 (710) kcal/d); P<0·01). Significant differences in mean nutrient intakes between the R24W and the FR ranged from –54·8% (i.e. lower value with R24W) for niacin to +40·0% (i.e. higher value with R24W) for alcohol. Sex- and energy-adjusted deattenuated correlations between the two methods were significant for all nutrients except Zn (range: 0·35–0·72; P<0·01). Cross-classification demonstrated that 40·0% of participants were classified in the same quartile with both methods, while 40·0% were classified in the adjacent quartile and only 3·6% were grossly misclassified (1st v. 4th quartile). Analysis of Bland–Altman plots revealed proportional bias between the two assessment methods for 8/24 nutrients.

These data suggest that the R24W presents an acceptable relative validity as compared with the FR for estimating usual dietary intakes in a cohort of French Canadians.

For dietary assessment, mobile devices with a camera can be used as an alternative to hand-written paper records. The Nutritional Tracking Information Smartphone (Nutris-Phone) study aimed to examine relative validity and feasibility of a photo-based dietary record in everyday life.

Parallel to the photo-based technique, a weighed record was performed. Participant satisfaction was assessed by questionnaire. A trained nutrition scientist evaluated portion sizes and nutrient content was calculated (DGExpert). Spearman correlation and Bland–Altman analyses were applied.

Healthy, non-pregnant volunteers (≥18 years) without intent to lose weight recruited at Ulm University, Germany.

Sixty-six participants (36 % males, median age 22·0 (interquartile range 20·0–25·0) years) took pictures of foods and beverages consumed with a commercially available mobile phone.

Significant correlation between the photo-based and weighed record was observed: energy (r=0·991), carbohydrate (r=0·980), fat (r=0·972), protein (r=0·988), fibre (r=0·941). Bland–Altman analyses indicated comparable means and acceptable 95 % limits of agreement (energy: −345·2 to 302·9 kJ (−82·5 to 72·4 kcal); carbohydrate: −15·2 to 13·1 g; fat: −6·4 to 6·4 g; protein: −5·9 to 5·6 g; fibre: −2·7 to 2·5 g). However, with increasing intake level, underestimation by the digital method was present (except for fat, all P<0·01). Over 80 % of participants were satisfied with the photo-based record. In nearly 90 %, technical implementation was without major problems.

Compared with a weighed record, the photo-based dietary record seems to be valid, feasible and user-friendly to estimate energy, macronutrient and fibre intakes, although a systematic bias with increasing levels of intake should be kept in mind.

To assess the relative validity and reproducibility of the semi-quantitative FFQ (SFFQ) applied in the evaluation of a community intervention study, SoL-Bornholm, for estimating food intakes.

The reference measure was a 4 d estimated food record. The SFFQ was completed two times separated by a 1-month period in order to test reproducibility.

The Capital Region and the Regional Municipality of Bornholm, Denmark.

A total of fifty-four children aged 3–9 years were enrolled in the study.

In terms of validity, the SFFQ generally overestimated intakes compared with the food records, especially for vegetables. For most intakes, the mean difference increased with increasing intake. Gross misclassification was on average higher for energy and nutrients (17 %) than for foods (8 %). Spearman correlation coefficients were significant for twelve out of fourteen intakes, ranging from 0·29 to 0·63 for foods and from 0·12 to 0·48 for energy and nutrients. Comparing the repeated SFFQ administrations, the intakes of the first SFFQ were slightly higher than those of the second SFFQ. Gross misclassification was low for most intakes; on average 6 % for foods and 8 % for energy and nutrients. Intra-class correlations were significant for all intakes, ranging from 0·30 to 0·82 for foods and from 0·46 to 0·81 for energy and nutrients.

The results indicate that the SFFQ gives reproducible estimates. The relative validity of the SFFQ was low to moderate for most intakes but comparable to other studies among children.

To assess the relative validity of a semi-quantitative, web-based FFQ completed by female pregnancy planners in the Danish ‘Snart Forældre’ study.

We validated a web-based FFQ based on the FFQ used in the Danish National Birth Cohort against a 4 d food diary (FD) and assessed the relative validity of intakes of foods and nutrients. We compared means and medians of intakes, and calculated Pearson correlation coefficients and de-attenuated coefficients to assess agreement between the two methods. We also calculated the proportion correctly classified based on the same or adjacent quintile of intake and the proportion of grossly misclassified (extreme quintiles).

Participants (n 128) in the ‘Snart Forældre’ study who had completed the web-based FFQ were invited to participate in the validation study.

Participants in the ‘Snart Forældre’ study, in total ninety-seven women aged 20–42 years.

Reported intakes of dairy products, vegetables and potatoes were higher in the FFQ compared with the FD, whereas reported intakes of fruit, meat, sugar and beverages were lower in the FFQ than in the FD. Overall the de-attenuated correlation coefficients were acceptable, ranging from 0·33 for energy to 0·93 for vitamin D. The majority of the women were classified in the same or adjacent quintile and few women were misclassified (extreme quintiles).

The web-based FFQ performs well for ranking women of reproductive age according to high or low intake of foods and nutrients and, thus, provides a solid basis for investigating associations between diet and fertility.

To assess the relative validity and repeatability of a sixty-four-item FFQ for estimating dietary intake of Zn and its absorption modifiers in Saudi adults. In addition, we used the FFQ to investigate the effect of age and gender on these intakes.

To assess validity, all participants completed the FFQ (FFQ1) and a 3 d food record. After 1 month, the FFQ was administered for a second time (FFQ2) to assess repeatability.

Jeddah, Saudi Arabia.

One hundred males and females aged 20–30 years and 60–70 years participated.

Mean intakes of Zn and protein from FFQ1 were significantly higher than those from the food record while there were no detectable differences between tools for measurement of phytic acid intake. Estimated intakes of Zn, protein and phytate by both approaches were strongly correlated (P<0·001). Bland–Altman analysis showed for protein that the difference in intake as measured by the two methods was similar across the range of intakes while for Zn and phytic acid, the difference increased with increasing mean intake. Zn and protein intakes from FFQ1 and FFQ2 were highly correlated (r>0·68, P<0·001) but were significantly lower at the second measurement (FFQ2). Older adults consumed less Zn and protein compared with young adults. Intakes of all dietary components were lower in females than in males.

The FFQ developed and tested in the current study demonstrated reasonable relative validity and high repeatability and was capable of detecting differences in intakes between age and gender groups.

To evaluate the reliability and relative validity of a semi-quantitative FFQ for assessing the habitual intake of multiple nutrients in New Zealand (NZ) adults over the past 12 months.

A 154-item FFQ was developed. After initial pre-testing, reliability was assessed using intra-class correlations. Relative validity was assessed by comparing nutrient intakes derived from the FFQ v. those from an 8 d diet record (8dWDR) collected over 12 months and selected blood biomarkers, using Spearman correlations. Supplementary cross-classification and Bland–Altman analyses were performed to assess validity of the FFQ v. the 8dWDR.

Dunedin, NZ.

One hundred and thirty-two males and females aged 30–59 years who completed all FFQ and 8dWDR and provided a blood sample.

Reliability coefficients ranged from 0·47 for Ca to 0·83 for alcohol, with most values falling between 0·60 and 0·80. The highest validity coefficients for energy-adjusted data were observed for alcohol (0·74), cholesterol (0·65) and β-carotene (0·58), and the lowest for Zn (0·24) and Ca (0·28). For all energy-adjusted nutrients mean percentage correct classification was 77·9 % and gross misclassification was 4·5 %. Results of Bland–Altman analyses showed wide limits of agreement for all micronutrients but high agreement was observed for most macronutrients (99 % for protein, 103 % for total fat). When compared with biomarkers, energy-adjusted coefficients were 0·34 for β-carotene and 0·33 for vitamin C.

The FFQ provides highly repeatable measurements and good validity in ranking individuals’ intake, suggesting that it will be a useful tool to assess nutrient intake of NZ adults in future research.

To determine the relative validity of the pre-coded food diary applied in the Danish National Survey of Dietary Habits and Physical Activity.

A cross-over study among seventy-two adults (aged 20 to 69 years) recording diet by means of a pre-coded food diary over 4 d and a 4 d weighed food record. Intakes of foods and drinks were estimated, and nutrient intakes were calculated. Means and medians of intake were compared, and cross-classification of individuals according to intake was performed. To assess agreement between the two methods, Pearson and Spearman's correlation coefficients and weighted kappa coefficients were calculated.

Validation study of the pre-coded food diary against a 4 d weighed food record.

Seventy-two volunteer, healthy free-living adults (thirty-five males, thirty-seven females).

Intakes of cereals and vegetables were higher, and intakes of fruit, coffee and tea were lower, in the weighed food record compared with the food diary. Intakes of nutrients were grossly the same in the two methods, except for protein, where a higher intake was recorded in the weighed record. In general, moderate agreement between the two methods was found.

Participants were classified moderately correct according to food and nutrient intakes assessed in the pre-coded food diary; however values of absolute food intakes should be used and interpreted with caution. Improvement of the methods to estimate portion size may increase the accuracy of the dietary intake estimates.

To compare the relative validity of food group intakes derived from a comprehensive self-administered diet history questionnaire (DHQ) and a brief-type DHQ (BDHQ) developed for the assessment of Japanese diets during the previous month using semi-weighed dietary records (DR) as a reference method.

Between November 2002 and September 2003, a 4 d DR (covering four non-consecutive days), a DHQ (150-item semi-quantitative questionnaire) and a BDHQ (fifty-eight-item fixed-portion-type questionnaire) were completed four times (once per season) at 3-month intervals.

Three areas in Japan: Osaka, Nagano and Tottori.

Ninety-two Japanese women aged 31–69 years and ninety-two Japanese men aged 32–76 years.

Median food group intakes were estimated well for approximately half of the food groups. No statistically significant differences were noted between a 16 d DR and the first DHQ (DHQ1) or between the DR and the first BDHQ (BDHQ1) in fifteen (44 %) and fifteen (52 %) food items for women and in fourteen (41 %) and sixteen (55 %) food items for men, respectively, indicating that both questionnaires estimated median values reasonably well. Median Spearman's correlation coefficients with the DR were 0·43 (range: −0·09 to 0·77) for DHQ1 and 0·44 (range: 0·14 to 0·82) for BDHQ1 in women, with respective values of 0·44 (range: 0·08 to 0·87) and 0·48 (range: 0·22 to 0·83) in men, indicating reasonable ranking ability. Similar results were observed for mean values of the four DHQ and BDHQ.

In terms of food intake estimates, both the DHQ and the BDHQ showed reasonable validity.

Although dietary pattern approaches derived from dietary assessment questionnaires are widely used, only a few studies in Western countries have reported the validity of this approach. We examined the relative validity of dietary patterns derived from a self-administered diet history questionnaire (DHQ) among Japanese adults.

The DHQ, assessing diet during the preceding month, and 4 d dietary records (DR) were collected in each season over one year. To derive dietary patterns, 145 food items in the DHQ and 1259 in the DR were classified into thirty-three predefined food groups, and entered into a factor analysis.

Three areas in Japan; Osaka (urban), Nagano (rural inland) and Tottori (rural coastal).

A total of ninety-two Japanese women and ninety-two Japanese men aged 31–76 years.

We identified three dietary patterns (‘healthy’, ‘Western’ and ‘Japanese traditional’) in women and two (‘healthy’ and ‘Western’) in men, which showed a relatively similar direction and magnitude of factor loadings of food groups across the first and mean of four DHQ (DHQ1 and mDHQ, respectively) and 16 d DR. The Pearson correlation coefficients between DHQ1 and 16 d DR for the healthy, Western and Japanese traditional patterns in women were 0·57, 0·36 and 0·44, and for the healthy and Western patterns in men were 0·62 and 0·56, respectively. When mDHQ was examined, the correlation coefficients improved for women (0·45–0·69).

Dietary patterns derived from the DHQ could be used for epidemiological studies as surrogates of those derived from DR.

To compare different statistical methods for assessing the relative validity of a self-administered, 150-item, semi-quantitative food-frequency questionnaire (FFQ) with 4-day weighed diet records (WR).

Subjects completed the Scottish Collaborative Group FFQ and carried out a 4-day WR. Relative agreement between the FFQ and WR for energy-adjusted nutrient intakes was assessed by Pearson and Spearman rank correlation coefficients, the percentages of subjects classified into the same and opposite thirds of intake, and Cohen's weighted kappa.

Forty-one men, mean age 36 (range 21-56) years, and 40 women, mean age 33 (range 19-58) years, recruited from different locations in Aberdeen, Scotland.

Spearman correlation coefficients tended to be lower than Pearson correlation coefficients, and were above 0.5 for 10 of the 27 nutrients in men and 17 of the 27 nutrients in women. For nutrients with Spearman correlation coefficients above 0.5, the percentage of subjects correctly classified into thirds ranged from 39 to 78%, and weighted kappa values ranged from 0.23 to 0.66.

Both Spearman correlation coefficients and weighted kappa values are useful in assessing the relative validity of estimates of nutrient intake by FFQs. Spearman correlation coefficients above 0.5, more than 50% of subjects correctly classified and less than 10% of subjects grossly misclassified into thirds, and weighted kappa values above 0.4 are recommended for nutrients of interest in epidemiological studies.

To assess validity of the Nambour food-frequency questionnaire (FFQ) relative to weighed food records (WFRs), and the extent to which selected demographic, anthropometric and social characteristics explain differences between the two dietary methods.

Inter-method validity study; 129-item FFQ vs. 12 days of WFR over 12 months.

Community-based Nambour Skin Cancer Prevention Trial.

One hundred and fifteen of 168 randomly selected participants in the trial (68% acceptance rate) aged 25–75 years.

Spearman correlations between intakes from the two methods ranged from 0.18 to 0.71 for energy-adjusted values. Differences between FFQ and WFR regressed on personal characteristics were significantly associated with at least one characteristic for 16 of the 21 nutrients. Sex was significantly associated with differences for nine nutrients; body mass index (BMI), presence of any medical condition and age were each significantly associated with differences for three to six nutrients; use of dietary supplements and occupation were associated with differences for one nutrient each. There was no consistency in the direction of the significant associations. Regression models explained from 7% (riboflavin) to 27% (saturated fat) of variation in differences in intakes.

The relative validity of FFQ estimates for many nutrients is quite different for males than for females. Age, BMI, medical condition and level of intake were also associated with relative validity for some nutrients, resulting in the need to adjust intakes estimates for these in modelling diet-disease relationships. Estimates for cholesterol, β-carotene equivalents, retinol equivalents, thiamine, riboflavin and calcium would not benefit from this.

To apply structural equation modelling (SEM) and estimation of variance components to the relative validation data obtained from the quantitative food frequency questionnaire (QFFQ) used in the Transition, Health and Urbanisation in South Africa (THUSA) study.

A cross-sectional study.

A community-based field study in an African population conducted during 1996.

Residents of the North West Province, South Africa, aged between 15 and 65 years.

Relative validity of the QFFQ was tested against 7-day weighed food records, 24-hour urinary nitrogen (UN) excretion and estimated basal metabolic rate (BMR). SEM and estimation of variance components were applied to the log-transformed energy, protein, fat, calcium, iron, vitamin A and vitamin C intakes. UN excretion was used as a biomarker in the application of the SEM to protein and estimated BMR to energy intakes.

Constant bias (αQ) derived by the SEM varied from 0.85 (vitamin C) to 5.8 (energy). There was significant proportional bias for all nutrients except vitamin C. Validation coefficients (ρ(Q, T )) varied from 0.3 (fat, calcium, iron) to 0.7 (vitamin C). The inclusion of estimated BMR in the SEM for energy increased ρ(Q, T ) from 0.38 to 0.42. The estimation of variance components gave slightly lower correlations for the relationship between intakes from the QFFQ and the unknown true intake.

Robust statistical methods were successfully applied in a relative validation study for a QFFQ in an African population. Estimated BMR as a biomarker for energy intake produced more meaningful results than UN excretion as a biomarker for protein intake.