Validity and reproducibility of a computerised tool for assessing the iron, calcium and vitamin C intake of Belgian women

Development and validity of a short web-based semi-quantitative Food Frequency Questionnaire applicable in both clinical and research setting: an evolution over time

Background

Assessing dietary intake is valuable both in clinical practice and in research. In research and in clinical practice, long-term habitual dietary intake is most often of interest. Therefore, a web-based semi-quantitative Food Frequency Questionnaire (FFQ) was developed to measure habitual intake of nutrients and foods.

Aim

This study aimed to assess content validity, convergent validity, and reliability of a 32-item semi-quantitative FFQ for adults.

Methods

A total of three different cohorts of Flemish adults were recruited in the past 10 years. The first cross-sectional validation study took place in 2013, consequently in 2019 and 2021. Content validity was assessed in 2019 through a semi-structured cognitive interview. Convergent validity was assessed by examining mean differences, Wilcoxon signed-rank test, Spearman's correlation coefficients (SCC), and Bland-Altman analysis for energy, nutrient, and food group intake compared with a 3-day food record (FR). Additionally, consumers-only analysis was performed together with cross-classification analysis by assessing the ranking capabilities of the FFQ into quartiles and weighted kappa. Reliability was assessed through the evaluation of SCC and intra-class correlation (ICC) of test-retest assessment of the FFQ.

Results

Spearman's correlation coefficient (SCC) for energy and absolute nutrient intake between the FFQ and the FR ranged from 0.02 to 0.54. Compared with absolute macronutrients, higher SCC was found for the majority of the relative macronutrient intake and most food groups. Bland-Altman plots showed improved agreement and decreasing bias between the FFQ and the FR over time. Misclassification of the FFQ for nutrients was acceptable and decreased over time (7.4, 7.5, and 6.8% in 2013, 2019, and 2021, respectively), but weighted kappa remained mostly fair (κ ≤ 0.20). The reliability of the FFQ was good and improved over time (mean SCC of 0.65 and 0.66 p <0.001 in 2013 and 2019).

Conclusion

The short web-based FFQ is an easy, low-cost, and feasible tool with good reliability, low misclassification, and acceptable validity to compare nutrient densities and food group intake at the population level. The measurement of absolute intake remains debatable.

The Reproducibility and Relative Validity of a Food Frequency Questionnaire for Identifying Iron-Related Dietary Patterns in Pregnant Women

Analyzing pregnant women’s iron intake using dietary patterns would provide information that considers dietary relationships with other nutrients and their sources. The objective of this study was to evaluate the reproducibility and relative validity of a Qualitative Food Frequency Questionnaire to identify iron-related dietary patterns (FeP-FFQ) among Mexican pregnant women. A convenience sample of pregnant women (n = 110) completed two FeP-FFQ (FeP-FFQ1 and FeP-FFQ2) and a 3-day diet record (3DDR). Foods appearing in the 3DDR were classified into the same food groupings as the FeP-FFQ, and most consumed foods were identified. Exploratory factor analysis was used to determine dietary patterns. Scores were compared (FeP-FFQ for reproducibility and FeP-FFQ1 vs. 3DDR for validity) through intraclass correlation coefficients (ICC), cross-classification, Bland−Altman analysis, and weighed Cohen kappa (κw), using dietary patterns scores tertiles. Two dietary patterns were identified: “healthy” and “processed foods and dairy”. ICCs (p < 0.01) for “healthy” pattern and “processed foods and dairy” pattern were 0.76 for and 0.71 for reproducibility, and 0.36 and 0.37 for validity, respectively. Cross-classification and Bland−Altman analysis showed good agreement for reproducibility and validity; κw values showed moderate agreement for reproducibility and low agreement for validity. In conclusion, the FeP-FFQ showed good indicators of reproducibility and validity to identify dietary patterns related to iron intake among pregnant women.

Evaluation of tools used to measure calcium and/or dairy consumption in adults

OBJECTIVE

To identify and critique tools for the assessment of Ca and/or dairy intake in adults, in order to ascertain the most accurate and reliable tools available.

DESIGN

A systematic review of the literature was conducted using defined inclusion and exclusion criteria. Articles reporting on originally developed tools or testing the reliability or validity of existing tools that measure Ca and/or dairy intake in adults were included. Author-defined criteria for reporting reliability and validity properties were applied.

SETTING

Studies conducted in Western countries.

SUBJECTS

Adults.

RESULTS

Thirty papers, utilising thirty-six tools assessing intake of dairy, Ca or both, were identified. Reliability testing was conducted on only two dairy and five Ca tools, with results indicating that only one dairy and two Ca tools were reliable. Validity testing was conducted for all but four Ca-only tools. There was high reliance in validity testing on lower-order tests such as correlation and failure to differentiate between statistical and clinically meaningful differences. Results of the validity testing suggest one dairy and five Ca tools are valid. Thus one tool was considered both reliable and valid for the assessment of dairy intake and only two tools proved reliable and valid for the assessment of Ca intake.

CONCLUSIONS

While several tools are reliable and valid, their application across adult populations is limited by the populations in which they were tested. These results indicate a need for tools that assess Ca and/or dairy intake in adults to be rigorously tested for reliability and validity.

Dietary assessment methods for intakes of iron, calcium, selenium, zinc and iodine

The EURopean micronutrient RECommendations Aligned (EURRECA) Network of Excellence is working towards developing aligned micronutrient recommendations across Europe. The purpose of the present study was to conduct a review of methods used in validation studies carried out in adults assessing dietary intake of EURRECA priority minerals. A search strategy and inclusion criteria were defined and a scoring system was developed to rate the quality of each validation study that produced a quality index with possible scores obtained ranging from 0.5 to 7. A MEDLINE and EMBASE literature review was conducted. Articles/validation studies meeting the inclusion criteria included: 79/88 for Fe; 95/104 for Ca; 13/15 for Se; 29/30 for Zn; 7/9 for iodine. The most frequently used method to ascertain dietary intake was the Food Frequency Questionnaire (FFQ), whereas dietary records (DR) and 24 h recalls were the most used reference methods. The correlation coefficients (CC) between study mineral intakes estimated by FFQ and the reference method were weighted according to the study's quality index and obtained acceptable to good ratings, ranging from 0.36 to 0.60 when the reference method was DR and from 0.41 to 0.58 when the reference was 24 h recalls. A minority of studies (n 9) used biomarkers for validation and among these, five included iodine obtaining a CC of 0.47. The FFQ was seen as a valid method for assessing mineral intake, particularly for Ca and, to a lower extent, for iodine and Zn. Se and Fe showed only acceptable correlations. The present review provides new insights regarding the characteristics that assessment methods for dietary mineral intakes should fulfil.

Dietary assessment methods for micronutrient intake: a systematic review on vitamins

The EURRECA Network of Excellence is working towards the development of aligned micronutrient recommendations across Europe. The purpose of the present study was to define how to identify dietary intake validation studies in adults pertaining to vitamins. After establishing a search strategy, we conducted a MEDLINE and EMBASE literature review. A scoring system was developed to rate the quality of each validation study according to sample size, statistical methods, data collection procedure, seasonality and vitamin supplement use. This produced a quality index with possible scores obtained ranging from 0.5 to 7. Five thousand four-hundred and seventy-six papers were identified. The numbers meeting the inclusion criteria were: for vitamin A, 76; vitamin C, 108; vitamin D, 21; vitamin E, 75; folic acid, 47; vitamin B12, 19; vitamin B6, 21; thiamine, 49; riboflavin, 49; and niacin, 32. The most frequently used method to ascertain dietary intake was the Food Frequency Questionnaire (FFQ), whereas dietary records (DR) and 24-h recalls were the most used reference methods. The correlation coefficients (CC) between vitamin intakes estimated by FFQ and the reference method were weighted according to the study's quality index and ranged from 0.41 to 0.53 when the reference method was the DR and from 0.43 to 0.67 when the reference was 24-h recalls. A minority of studies (n 33) used biomarkers for validation and in these the CC ranged from 0.26 to 0.38. The FFQ is an acceptable method of assessing vitamin intake. The present review provides new insights regarding the characteristics that assessment methods for dietary intake should fulfil.

Feasibility of the Young Children's Nutrition Assessment on the Web

Methods to assess detailed dietary data are cumbersome, expensive, and difficult to implement with large samples. The purpose of the present article was to evaluate the feasibility of collecting data from parents about their child's diet using an online dietary assessment tool. The Young Children's Nutrition Assessment on the Web was developed as part of a longitudinal study of familial influences on food intake of preschool children. A sample of 862 parents from 56 nursery schools completed a paper-and-pencil questionnaire containing sociodemographic variables and a food frequency questionnaire about their child's diet and psychosocial variables. Subsequently, a subset of parents was asked to either complete a paper-and-pencil food diary or the Young Children's Nutrition Assessment on the Web (n=88); those remaining who provided e-mail addresses were asked to complete the Young Children's Nutrition Assessment on the Web (n=467) and a user-acceptability questionnaire. This resulted in 39 useful paper-and-pencil diaries, 217 useful Young Children's Nutrition Assessments on the Web, and 164 user-acceptability questionnaires. Mann-Whitney U tests comparing nutrient (macronutrients, vitamin C, calcium, and fiber) and food group intakes from data collected with the Young Children's Nutrition Assessment on the Web vs paper-and-pencil diaries resulted in no substantial differences except for water. Attrition analyses indicated that dropout for the online assessment was associated with the sex of the respondent (father completing the questionnaire), lower social status, being a smoker, and lower nutrition knowledge. The online measure was well-received by respondents. The majority found it user-friendly (79%), attractive (68%), and clear (93%). The Young Children's Nutrition Assessment on the Web is a promising tool to collect online dietary data in large-scale surveys.

How accurate are adolescents in portion-size estimation using the computer tool Young Adolescents' Nutrition Assessment on Computer (YANA-C)?

Computer-administered questionnaires have received increased attention for large-scale population research on nutrition. In Belgium-Flanders, Young Adolescents' Nutrition Assessment on Computer (YANA-C) has been developed. In this tool, standardised photographs are available to assist in portion-size estimation. The purpose of the present study is to assess how accurate adolescents are in estimating portion sizes of food using YANA-C. A convenience sample, aged 11–17 years, estimated the amounts of ten commonly consumed foods (breakfast cereals, French fries, pasta, rice, apple sauce, carrots and peas, crisps, creamy velouté, red cabbage, and peas). Two procedures were followed: (1) short-term recall: adolescents (n73) self-served their usual portions of the ten foods and estimated the amounts later the same day; (2) real-time perception: adolescents (n128) estimated two sets (different portions) of pre-weighed portions displayed near the computer. Self-served portions were, on average, 8 % underestimated; significant underestimates were found for breakfast cereals, French fries, peas, and carrots and peas. Spearman's correlations between the self-served and estimated weights varied between 0·51 and 0·84, with an average of 0·72. The κ statistics were moderate (>0·4) for all but one item. Pre-weighed portions were, on average, 15 % underestimated, with significant underestimates for fourteen of the twenty portions. Photographs of food items can serve as a good aid in ranking subjects; however, to assess the actual intake at a group level, underestimation must be considered.

Determinants of ferritin and soluble transferrin receptors as iron status parameters in young adult women

Objective

To investigate associations between nutritional and non-nutritional variables and Fe status parameters, i.e. serum ferritin and soluble transferrin receptors (sTfR).

Design

Cross-sectional design. Fe status parameters were determined on a fasting venous blood sample. Nutritional variables were assessed using a 2 d food record and non-nutritional variables by a general questionnaire. A general linear model was used to investigate associations between the variables and Fe status parameters.

Setting

Region of Ghent, Dutch-speaking part of Belgium.

Subjects

Random sample of 788 women (aged 18–39 years).

Results

Median (interquartile range) ferritin and sTfR were 26·3 (15·9, 48·9) ng/ml and 1·11 (0·95, 1·30) mg/l, respectively. BMI and alcohol intake were positively associated and tea intake was negatively associated with serum ferritin. Women who used a non-hormonal intra-uterine device, who gave blood within the past year or who had been pregnant within the past year had lower serum ferritin values than their counterparts. Significant determinants of sTfR were smoking habit and pregnancy, with higher values for non-smokers and women who had been pregnant within the past year.

Conclusions

The present study indicates that contraceptive use, time since last blood donation, time since last pregnancy, BMI, alcohol and tea intake are determinants of Fe stores, whereas smoking habit and time since last pregnancy are determinants of tissue Fe needs. When developing strategies to improve Fe status, special attention should be given to women who use a non-hormonal intra-uterine device, gave blood within the past year and had been pregnant within the past year.

Development of a tool for the assessment of calcium and vitamin D intakes in clinical settings

The study aim was to develop a tool (software and ruler) to assess the dietary calcium and vitamin D intakes in Portugal, and evaluate the usefulness of non-dietary variables as intake predictors. Our findings indicated that is possible to estimate both using three and six food items, respectively, and non-dietary predictors.

INTRODUCTION

The study aim was to develop a tool to assess the dietary calcium and vitamin D intakes in Portugal, and evaluate the usefulness of non-dietary variables as predictors.

METHODS

Trained interviewers collected information of 2,414 adults of Porto, Portugal, using a structured questionnaire and a validated semi-quantitative food frequency questionnaire (FFQ). Food items with the highest contribution to the total intake and non-dietary predictors (gender, age and body mass index (BMI)) were selected for the tool. Different statistical approaches were used to predict the intake. A Bland-Altman plot compared the predictions from the tool and the full FFQ.

RESULTS

The items selected to predict intake were milk (38%), cheese (12%), yogurt (10%) and gender for calcium and oily fish (39%), canned fish (9%), white fish (7%), eggs (5%), red meat (5%), age and BMI for vitamin D. The Bland-Altman plot showed that the mean differences were 0.0 (limits of agreement = [-220.67; 220.77]) mg/day and 0.0 (limits of agreement = [-1.03; 1.05]) microg/day, respectively for calcium and vitamin D.

CONCLUSION

The equations estimated by the best statistical model to predict the calcium and vitamin D intake allowed for the design of a software and a circular ruler useful in clinical settings.

Validity and reproducibility of a self-administered semi-quantitative food-frequency questionnaire for estimating usual daily fat, fibre, alcohol, caffeine and theobromine intakes among Belgian post-menopausal women

A novel food-frequency questionnaire (FFQ) was developed and validated to assess the usual daily fat, saturated, mono-unsaturated and poly-unsaturated fatty acid, fibre, alcohol, caffeine, and theobromine intakes among Belgian post-menopausal women participating in dietary intervention trials with phyto-oestrogens. The relative validity of the FFQ was estimated by comparison with 7 day (d) estimated diet records (EDR, n 64) and its reproducibility was evaluated by repeated administrations 6 weeks apart (n 79). Although the questionnaire underestimated significantly all intakes compared to the 7 d EDR, it had a good ranking ability (r 0.47-0.94; weighted kappa 0.25-0.66) and it could reliably distinguish extreme intakes for all the estimated nutrients, except for saturated fatty acids. Furthermore, the correlation between repeated administrations was high (r 0.71-0.87) with a maximal misclassification of 7% (weighted kappa 0.33-0.80). In conclusion, these results compare favourably with those reported by others and indicate that the FFQ is a satisfactorily reliable and valid instrument for ranking individuals within this study population.

Criterion validity and user acceptability of a CD-ROM-mediated food record for measuring fruit and vegetable consumption among black adolescents

OBJECTIVES

To determine the criterion validity and user acceptability of the Healthy Eating Self-Monitoring Tool (HEST), a CD-ROM-mediated food record for measuring fruit and vegetable consumption among economically disadvantaged black adolescents.

DESIGN

Item intakes, daily intake measures of fruit, vegetables and juices, and daily and total fruit and vegetable intake assessed with the HEST over a 3 d interval were compared with observed intake using Spearman correlations and Wilcoxon signed ranks tests. Mean ratings of participants' interest in, enjoyment of and likelihood of recommending the HEST to peers were compared with an a priori criterion rating for establishing user acceptability of the HEST.

SETTING

Youth services agencies in New York City.

SUBJECTS

Eighty-nine black adolescents aged 11 to 14 years.

RESULTS

Spearman correlations were significant for 67 % of items, for daily intake measures of fruit (days 1 and 3), vegetables and juices (days 1 and 2), and for fruit and vegetable intake (all three days). Wilcoxon signed ranks tests found non-significant intake differences for 78 % of these items, for daily intake measures of fruit and vegetables, and for fruit and vegetable intake (days 2 and 3). HEST-recorded 3 d intake of 14.65 servings was significantly correlated with and did not differ significantly from observed 3 d intake of 15.21 servings. Youths' HEST-recorded intake was accurate to within 0.56 of a serving of their observed intake. Mean ratings of the HEST were above the criterion rating across user acceptability dimensions assessed.

CONCLUSIONS

The HEST is a promising food record approach that is acceptable to youths.

Nutrient intakes of Greek forest workers and researchers do not meet all Reference Dietary Intakes

In heavy work such as forest work, nutrient demand and energy expenditure are high. Therefore, adequate nutrient and energy intake of forest workers is of paramount importance. The objective of this cross-sectional study was to investigate the daily nutrient intake of forest workers and to determine if it meets the Reference Dietary Intakes (RDIs). A total of 21 forest workers and 21 researchers, who served as a control group, were enrolled. Nutrient intake was assessed on the basis of a 24-hour diet recall questionnaire, repeated for 3 consecutive weekdays. Daily nutrient intake was calculated using the NutriBase IV Clinical Edition Software package. Energy, protein, total lipids, saturated fatty acids, cholesterol, phosphorus, and sodium intake of forest workers was higher than the RDIs and significantly higher (P < .05) than that of researchers. Most forest workers (90.47%) and researchers (95.32%) consumed less carbohydrate than the RDIs. Dietary fiber, riboflavin, vitamin E, vitamin D, and minerals intake was less than the RDI in both groups. Especially low was the daily intake of vitamin D and iodine in forest workers in comparison to RDIs and researchers. The results indicate that fundamental changes in daily nutrient intake for both groups are recommended.

Iron intake in relation to diet and iron status of young adult women

AIMS

To determine the iron intake and food sources of iron in young adult women and to compare women with high versus low iron intake on diet and iron status.

METHODS

Iron intake and food sources were assessed by a 2-day estimated food record. Iron status was determined by a fasting venous blood sample. Differences in diet and iron status between women with high versus low iron intake were examined by comparing women of the fourth respectively first quartile of total iron intake (mg/day).

RESULTS

The median total, heme and non-heme iron intake was 10.6, 0.6 and 9.8 mg/day, respectively. The median iron intake was 93 and 131% of the estimated average requirement (EAR) of the UK (11.4 mg/day) and USA (8.1 mg/day), respectively. The most important iron intake contributors were cereals and cereal products (31%), meat and meat products (12%) and vegetables (10%). Women with a high iron intake showed a significantly higher energy-adjusted intake of alcoholic beverages and soups and a lower intake of non-alcoholic beverages than women with a low iron intake. Approximately 5% of the women had anemia, of which 3% had iron deficiency anemia (IDA). Almost 20% was iron-deficient non-anemic. In this regard, no significant differences were found between the iron intake quartiles.

CONCLUSION

The median iron intake in this study population is considerably below the national recommended dietary allowance (20 mg/day). However, based on the approach of the Dietary Guidelines Advisory Committee, iron intake seems to pose no major health problem when using the EAR as a reference. The number of women with IDA was indeed not alarming (3%), although 20% was iron-deficient non-anemic. The question remains whether an increase in iron intake can improve iron status.

Meal-based intake assessment tool: relative validity when determining dietary intake of Fe and Zn and selected absorption modifiers in UK men

A computer-based dietary assessment tool, the meal-based intake assessment tool (MBIAT), is described. In the current study, dietary intakes of Fe and Zn fractions (total Fe, non-haem Fe, haem Fe, meat Fe, total Zn) and dietary components that influence Fe and Zn absorption (vitamin C, phytate, Ca, grams of meat/fish/poultry, black tea equivalents, phytate:Zn molar ratio) were assessed. The relative validity of the MBIAT was determined in forty-eight UK men aged 40 years and over by comparing its results with those from weighed diet records collected over 12 d. There was good agreement between the MBIAT and the weighed diet records for median intakes of total, non-haem, haem and meat Fe, Zn, vitamin C, phytate, grams of meat/fish/poultry and phytate:Zn molar ratio. Correlations between the two methods ranged from 0·32 (for Ca) to 0·80 (for haem Fe), with 0·76 for total Fe and 0·75 for Zn. The percentage of participants classified by the MBIAT into the same/opposite weighed diet record quartiles ranged from 56/0 for Fe and 60/0 for Zn to 33/10 for Ca. The questionnaire also showed an acceptable level of agreement between repeat administrations (e.g. a correlation for total Fe of 0·74). In conclusion, the MBIAT is appropriate for assessing group dietary intakes of total Fe and Zn and their absorption modifiers in UK men aged 40 years and over.

Iron nutrition in the UK: getting the balance right

Fe homeostasis is considered in the context of the UK diet, using information on Fe intake and status from the National Diet and Nutrition Surveys. The importance of assessing Fe availability rather than total Fe intake is discussed. Dietary and host-related factors that determine Fe bioavailability (Fe utilised for Hb production) are reviewed using information from single-meal studies. When adaptive responses are taken into consideration, foods associated with higher Fe status include meat (haem-Fe and the ‘meat factor’) and fruits and fruit juice (vitamin C). Foods that may have a negative impact include dairy products (Ca), high-fibre foods (phytate) and tea and coffee (polyphenols), but the effects are more apparent in groups with marginal Fe deficiency, such as women of childbearing age. Analysis of dietary intake data on a meal-by-meal basis is needed to predict the influence of changing dietary patterns on Fe nutrition in the UK. Current information suggests that in the UK Fe deficiency is a greater problem than Fe overload.

Evaluation of a 2-day food record to determine iron, calcium and vitamin C intake in young Belgian women

OBJECTIVE

Evaluation of a 2-day food record (FR) for the assessment of iron, calcium and vitamin C intake.

DESIGN

In a subsample of a large-scale epidemiological study, iron, calcium and vitamin C intake were estimated using a 2-day FR and compared to the nutrient intakes assessed by an 11-day FR (reference method).

SETTING

City of Ghent, Dutch speaking part of Belgium.

SUBJECTS

A number of 51 non-pregnant women (18-39 years).

RESULTS

Mean iron, calcium and vitamin C intakes were not significantly different between the reference method and 2-day FR. Correlation coefficients of 0.63 (iron) and 0.76 (calcium, vitamin C) were reached. The iron intake of 95% of the individuals assessed by the 2-day FR varied between 5 mg above or below the reference intake. Over 50% of the women were correctly classified and 4% or fewer were extremely misclassified by the 2-day FR. Mean 11-day FR intakes increased progressively over the tertiles defined by the 2-day FR. The 11-day energy intake was under-reported by 28% of the women; no over-reporters were identified.

CONCLUSIONS

The 2-day FR is able to estimate mean iron, calcium and vitamin C intake and to rank individuals along the distribution of intakes.