Evaluation of 2 brief instruments and a food-frequency questionnaire to estimate daily number of servings of fruit and vegetables

BACKGROUND: Measurement of fruit and vegetable intake is important in the surveillance of populations and in epidemiologic studies that examine the relations between diet and disease. Some situations require the use of brief dietary assessment tools. OBJECTIVE: Our objective was to evaluate the performance of 2 brief dietary assessment instruments, a 7-item standard screener and a new 16-item screener, and a complete food-frequency questionnaire (FFQ) in measuring total fruit and vegetable consumption. DESIGN: About 800 men and women from the National Institutes of Health-AARP Diet and Health Study completed an FFQ, 1 of the 2 screeners, and two 24-h dietary recalls. Fruit and vegetable intakes as measured by each screener and the FFQ were compared with estimated true usual intake by using a measurement-error model. RESULTS: Median daily servings of fruit and vegetables were underestimated by both screeners. The estimated agreement between true intake and the screener was higher for the new screener than for the standard screener and was higher for women than for men. The estimated agreement between true intake and the FFQ was higher than that for both screeners. Attenuation coefficients for the FFQ and screeners were comparable. CONCLUSIONS: For estimating median intakes of fruit and vegetables and the prevalence of recommended intakes being met, the use of screeners without appropriate adjustment is suboptimal. For estimating relative risks in the relations between fruit and vegetable intake and disease, screeners and this FFQ are similar in performance.     

The reliability of ten-year dietary recall: implications for cancer research

Remote dietary intakes may be more important than recent diet in the etiology of cancer because of the long latency in cancer development. We examined the reliability of remote dietary recall over 10 y. Subjects were 56 adults participating in a cancer prevention trial in Western Australia. All subjects completed a 28-d diet record (DR) in 1991. A food-frequency questionnaire (FFQ) modified to ask respondents about their diet 10 y earlier was sent to each subject for completion in 2001. Remote intakes recalled from 10 y earlier using the FFQ were compared with the DR using the limits of agreement (LOA) method and Pearson correlation coefficients. Mean intakes of most nutrients did not differ between dietary methods. The LOA indicated that the FFQ could under- or overestimate DR estimates by >/=50%. For many nutrients, agreement between methods depended on the magnitude of intake. Pearson's correlation coefficients ranged from 0.02 for retinol to 0.66 for alcohol. These findings are similar to those of other studies that examined the reliability of recent and remote dietary intakes. They also show that using this FFQ, remote diet recalled from 10 y earlier may be as reliable as recent dietary recall.     

Validation of a short food frequency questionnaire in Australian adults

The aim of this article is to report on the validity and internal consistency of a short food frequency questionnaire (FFQ) to measure dietary intake in Australian adults. A total of 407 individuals completed the short FFQ. The Cronbach’s alpha of 0.66 indicated acceptable internal consistency for the FFQ. Content validity was measured using factor analysis showed that 35% of total variance was explained by factor analysis. The FFQ was also validated against 31 3-day food records (FR). No significant difference between average intake of energy, most macronutrients, and some micronutrients between two instruments was identified. An acceptable levels of correlation (0.39–0.69) was observed between the two instruments. Bland and Altman’s plots showed relative agreement in both instruments with potential bias in measuring iron and iodine. The current FFQ can be an acceptable tool to quickly measuring dietary intake in Australian adults.     

Development of a simple food frequency questionnaire to estimate intakes of calcium and other nutrients for the prevention and management of osteoporosis

There have been no simple methods to estimate dietary nutrient intakes for the prevention and management of osteoporosis. The aim of this study was to develop and validate a new, simple food frequency questionnaire (FFQ) for dietary intake of calcium and other nutrients relevant to the bone health of adult Japanese women. We developed a 28-item FFQ. To validate this, 208 and 72 adult women aged between 18 and 69 y were recruited for testing reliability and reproducibility, respectively. In the 208 women, moderate-to-high Spearman's correlation coefficients between our FFQ and the conventional diet record method were found in intakes of calcium (r=0.668), sodium chloride (NaCl) (r=0.475), vitamin A (r=0.501), vitamin D (r=0.413), vitamin K (r=0.649), and energy (r=0.471). In the 72 women, coefficients of variance of the four repeated measurements of intakes throughout a year were 14.1% for calcium, 7.3% for NaCl, 21.2% for vitamin A, 13.6% for vitamin D, 36.8% for vitamin K, and 9.6% for energy. In conclusion, the FFQ we developed is a useful tool to evaluate the intake of dietary calcium of adult Japanese women. Although it can also measure intakes of dietary vitamin A, vitamin D, vitamin K, NaCl, and energy, further improvement is needed to measure intakes of these nutrients and energy.     

The Comparative Validity and Reproducibility of a Diet Quality Index for Adults: The Australian Recommended Food Score

Adult diet quality indices are shown to predict nutritional adequacy of dietary intake as well as all-cause morbidity and mortality. This study describes the reproducibility and validity of a food-based diet quality index, the Australian Recommended Food Score (ARFS). ARFS was developed to reflect alignment with the Australian Dietary Guidelines and is modelled on the US Recommended Food Score. Dietary intakes of 96 adult participants (31 male, 65 female) age 30 to 75 years were assessed in two rounds, five months apart. Diet was assessed using a 120-question semi-quantitative food frequency questionnaire (FFQ). The ARFS diet quality index was derived using a subset of 70 items from the full FFQ. Reproducibility of the ARFS between round one and round two was confirmed by the overall intraclass correlation coefficient of 0.87 (95% CI 0.83, 0.90), which compared favourably to that for the FFQ at 0.85 (95% CI 0.80, 0.89). ARFS was correlated with FFQ nutrient intakes, particularly fiber, vitamin A, beta-carotene and vitamin C (0.53, 95% CI 0.37–0.67), and with mineral intakes, particularly calcium, magnesium and potassium (0.32, 95% CI 0.23–0.40). ARFS is a suitable brief tool to evaluate diet quality in adults and reliably estimates a range of nutrient intakes.     

Production and validation of a food frequency questionnaire to estimate dietary fat intake

A quantitative 92-item food frequency questionnaire (FFQ), using photographs to estimate portion size, was developed from a 180-item FFQ and validated by comparison with weighed dietary records of 80 adults. The main aim of the FFQ was to classify subjects according to their fat intake as a percentage of total energy intake. Correlation coefficients and classification of individuals into thirds for fat (g), percentage energy from fat and total energy, showed good agreement between the FFQ and the diet record. There was significant difference in the mean percentage energy from fat but not in grams of fat or total energy intake estimated by the two methods. Intra-class correlation coefficients indicated a significant relationship between an individuals>> percentage energy from fat estimated by the FFQ and diet records. These results suggest that the FFQ was suitable for classifying individuals into groups based on their percentage energy from fat and for estimating the actual average fat and energy intake of groups, and that the FFQ may be useful for estimating the percentage energy from fat for an individual.     

Dietary fiber intake: assessing the degree of agreement between food frequency questionnaires and 4-day food records

OBJECTIVE: To assess the degree of agreement (comparability) between dietary fiber intakes reported on a food frequency questionnaire (FFQ) with 4-day food records (4DFR) and determine whether demographic, behavioral and biological factors influence comparability. METHODS: At baseline and year one, all participants in the Polyp Prevention Trial (PPT), a multi-center randomized, clinical trial of a low-fat, high fiber, high fruit/vegetable eating plan and recurrence of large bowel adenomatous polyps were instructed in dietary assessment and completed a 106-item FFQ and 4DFR that trained nutritionists reviewed. A random sub-cohort of participants (n = 399) was selected from the intervention and control arms of the PPT for analysis of both FFQ and 4DFR. RESULTS: Baseline crude and energy-adjusted fiber intakes were significantly higher in the 4DFR than the FFQ (P = 0.001). Using Bland-Altman statistics, the mean difference (FFQ-4DFR) was -0.11 g/MJ; while the limits of agreement were -1.45, 1.23 g/MJ. The mean fiber difference increased with increasing average intake (FFQ + 4DFR)/2, (P = 0.004) for men, but not women (P = 0.10), suggesting that fiber intake was under-estimated in the FFQ, relative to the 4-DFR, for men with low fiber intakes and over-estimated for men with high intakes. Smoking and gender significantly influenced the average intake at baseline, whereas other demographic and behavioral factors did not. Education was significantly associated with average difference in fiber intake at baseline, but not at year 1. CONCLUSIONS: This study of clinical trial volunteers revealed differences in the ability to comparably report fiber intake across tools by gender, smoking, and education, however participants' repeated training in dietary assessment improved comparability in reporting over time.     

A comparison of methods of assessment of dietary selenium intakes in Otago, New Zealand

The aims of the present study were (1) to compare three methods of assessment of dietary Se intake, i.e. chemical analysis of duplicate diets, diet records and a food-frequency questionnaire (FFQ) designed specifically for Se, and (2) to determine dietary Se intakes of residents of Otago, New Zealand. The FFQ was completed by 110 free-living adults. Diet records (3 d) and duplicate diet collections were carried out by forty-three of these subjects chosen on the basis of low blood Se concentration, and during a period when consumption of the high-Se foods fish, kidney, liver and Brazil nuts was discouraged. Mean Se intakes were similar for duplicate diet analysis (29 (SD 13) micrograms/d) and diet record assessments (28 (SD 15) micrograms/d). Estimates of intakes from the FFQ for the subgroup of forty-three subjects were higher (51 (SD 26) micrograms/d) than those from duplicate diets and diet records. Values from duplicate diet analysis and diet record assessments were strongly correlated (r 0.7, P = 0.0001), but difference plots indicated a lack of agreement between the two methods. Thus, diet record assessment was not adequate for predicting dietary Se intakes of individuals. Significant correlations were found for relationships between Se intake from duplicate diets (microgram/kg body weight per d) and plasma Se, Se intake from diet records (microgram/d and microgram/kg body weight per d) and plasma Se; and Se intake from the FFQ and whole-blood Se. Se intakes from duplicate diets and diet records were similar to those reported previously for New Zealanders, but lower than the recommended intakes in the USA (National Research Council, 1989), Australia (Truswell et al. 1990) and the UK (Department of Health, 1991) and the World Health Organization/Food and Agriculture Organization/International Atomic Energy Agency (1996) normative requirement.     

Relative validation of a short food frequency questionnaire to assess calcium intake in older adults

OBJECTIVE: To develop and validate a food frequency questionnaire (FFQ) for estimating calcium intake in community-dwelling older adults using a food record as the reference method. METHOD: A validation study involving 102 subjects (67 females) aged > or =65 years and residing independently in Adelaide, Australia, between 2002-06 was performed. Estimates of calcium intake over the last year were calculated from two versions (35 and 15 items) of the FFQ and compared with average intake from four days of non-consecutive food records (4DFR). RESULTS: Mean calcium intake from the 4DFR was 987 mg/day (95% CI 922-1051). The 35 and 15-item questionnaires gave mean intakes of 992 mg/day (95% CI 913-1,071) and 1017 mg/day (95% CI 927-1,106) respectively. Mean difference (95% limits of agreement) between the food record and the 35 and 15-item questionnaires was 5 mg (-739-729) and 28 mg (-936-879) respectively. The 15-item questionnaire demonstrated 82% sensitivity for classifying subjects with calcium intake below the estimated average requirement (EAR, 840 mg for males 51-70 years; 1,100 mg for females >51 years and males >70 years of age) and 46% specificity for classifying subjects with intake above the EAR. CONCLUSION: The FFQ evaluated as part of this study is one of very few that has been tested across both genders and in older adults specifically. The 15-item version has demonstrated a level of sensitivity and specificity comparable with other FFQs for evaluating calcium intake. Implications: The 15-item FFQ can be confidently used for measuring group mean calcium intake in older Australians or as a screening tool to allow health professionals to identify those who are most at risk of inadequate dietary calcium intake.     

Dietary iron, zinc, and calcium and the risk of lung cancer

BACKGROUND: Iron, zinc, and calcium are all involved in the metabolism of reactive oxygen species and may compete with each other for similar binding sites. Dietary intakes of these micronutrients have been associated with altered risks of colorectal, breast, and prostate cancers. METHODS: In this Massachusetts hospital-based case-control study of 923 patients with lung cancer and 1125 healthy controls, we studied the associations between dietary iron, zinc, and calcium intake and the risk of lung cancer. Dietary intake was assessed at the time of recruitment (1992 to 2000) with the use of a 126-item semiquantitative food-frequency questionnaire. We analyzed the data using multiple logistic regression models adjusting for smoking history and other potential risk factors. RESULTS: The adjusted odds ratios of dietary iron, zinc, and calcium from food sources were 1.45 (95% confidence interval=1.03-2.06), 0.71 (0.50-0.99), and 1.64 (1.17-2.29), respectively, for the highest quintile versus the lowest quintile of each micronutrient. Stronger associations between micronutrients and lung cancer risk were found when iron, zinc, and calcium were included together in the same model. The associations between dietary micronutrients intake and lung cancer risk were stronger among current smokers than among former smokers. When we examined intake from supplements as well as diet, associations were similar to those for diet alone. CONCLUSIONS: Dietary iron, zinc, and calcium may play an important role in the development of lung cancer, especially among current smokers. These results need to be confirmed in large prospective studies.     

Impact of season of food frequency questionnaire administration on dietary reporting

PURPOSE: Foods consumed near the time of food frequency questionnaire (FFQ) administration may prime the memory, such that FFQ responses emphasize recently consumed foods. This study investigates the effect of season of FFQ administration, a proxy for the recent diet, on FFQ responses. METHODS: FFQ data from 74,958 Shanghai Women's Health Study (SWHS) subjects were compared with FFQ data from these subjects by season of FFQ administration (i.e., winter, spring, summer, and fall). All analyses were adjusted for age, BMI, and energy intake. Furthermore, quintile categories derived from all study subjects were compared with categories derived from the distribution of subjects recruited in the same season. RESULTS: Compared with the study group as a whole, subjects completing the FFQ in winter reported higher intakes of meat (2.1%), vegetable (3.9%), fish (3.1%), and soy foods (4.1%), but lower fruit (- 3.9%) intake. Subjects completing the FFQ in summer reported lower than average meat (- 2.0%), vegetable (- 3.2%), fish (- 2.3%), and soy food (- 4.6%) intakes, but greater fruit intake (0.9%). Completion of the FFQ in spring and fall usually led to intermediate differences from the group average, although fruit intake was 5.9% higher among subjects completing the FFQ in the fall. Variations across macronutrients and micronutrients by season of FFQ administration were smaller. If seasonal FFQ reporting is ignored, up to 13% of subjects would be classified to a different diet intake exposure category. However, reclassification was always to an adjacent category. CONCLUSIONS: FFQ responses varied with season of FFQ administration, consistent with theory that current diet intake influences reporting of habitual past diet intake. However, season of FFQ administration did not alter dietary exposure category assignments sufficiently to effect interpretation of most epidemiologic studies.     

Assessment of Pre-Pregnancy Dietary Intake with a Food Frequency Questionnaire in Alberta Women

Purpose: Pre-pregnancy is an under-examined and potentially important time to optimize dietary intake to support fetal growth and development as well as maternal health. The purpose of the study was to determine the extent to which dietary intake reported by non-pregnant women is similar to pre-pregnancy dietary intake reported by pregnant women using the same assessment tool. Methods: The self-administered, semi-quantitative food frequency questionnaire (FFQ) was adapted from the Canadian version of the Diet History Questionnaire, originally developed by the National Cancer Institute in the United States. Pregnant women (n = 98) completed the FFQ which assessed dietary intake for the year prior to pregnancy. Non-pregnant women (n = 103) completed the same FFQ which assessed dietary intake for the previous year. Energy, macronutrients, and key micronutrients: long-chain omega-3 fatty acids, folate, vitamin B₆, vitamin B₁₂, calcium, vitamin D and iron were examined. Results: Dietary intake between groups; reported with the FFQ; was similar except for saturated fat; trans fat; calcium; and alcohol. Pregnant women reported significantly higher intakes of saturated fat; trans fat; and calcium and lower intake of alcohol in the year prior to pregnancy compared to non-pregnant women who reported intake in the previous year. Conclusions: Despite limitations; a FFQ may be used to assist with retrospective assessment of pre-pregnancy dietary intake.     

Validation of a food frequency questionnaire in the Hiroshima/Nagasaki Life Span Study

We evaluated the performance of a 22-item food frequency questionnaire (FFQ) administered in 1980-81 to 3,005 members of the Adult Health Study cohort, part of the Life Span Study. The questionnaire was compared with the records of a 24-hour dietary survey that was performed in 1984-85. From the dietary records, food and nutrient intakes were estimated. The association between the two measures of dietary intake was assessed using Mantel-Haenszel chi-square test and the Spearman's rank correlation coefficient. The frequency of food intake as measured by the FFQ was linearly associated with food intake as measured by the 24-hour diary, with the exception of dry fish. The highest correlations were observed for beverages, including coffee (0.51), milk (0.32) and black tea (0.26). Foods such as fruit (0.27), confectionery (0.23), rice (0.34) and bread (0.28) were also moderately correlated. These results show that, with the exception of dry fish, the FFQ is moderately correlated with the 24-hour diary and can be used to assess diet intake in this cohort.     

Evaluating the Validity of a Food Frequency Questionnaire in Comparison with a 7-Day Dietary Record for Measuring Dietary Intake in a Population of Survivors of Colorectal Cancer

BackgroundFood frequency questionnaires (FFQs) are a commonly used method to assess dietary intake in epidemiological studies. It is important to evaluate the validity of FFQs in the population of interest.ObjectiveTo evaluate the validity of an FFQ for measuring dietary intake in survivors of colorectal cancer (CRC), relative to a 7-day dietary record.DesignDietary intake was assessed 1 year after the end of CRC treatment. Participants first completed a 7-day dietary record and 2 weeks later a 253-item FFQ that measured intake in the preceding month.Participants/settingData were used from a subsample of participants (n=100) enrolled in an ongoing prospective study (EnCoRe study) in the Netherlands, from 2015 to 2018.Main outcome measuresEstimated intakes of total energy, 19 nutrients, and 20 food groups as well as scoring adherence to the dietary recommendations of the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) were compared between both dietary assessment methods.Statistical analyses performedMeans and standard deviations, Spearman rank correlations corrected for within-person variation and total energy, and κ agreement between quintiles were assessed.ResultsThe median Spearman correlation corrected for within-person variation for nutrients and total energy was 0.60. Correlations >0.50 were found for 15 of 19 nutrients, with highest agreement for vitamin B-12 (0.74), polysaccharides (0.75), and alcohol (0.91). On average, 73% (range=60% to 84%) of participants were classified into the exact same or adjacent nutrient quintile. The median Spearman correlation corrected for within-person variation for food groups was 0.62. Correlations >0.50 were found for 17 of 20 food groups, with highest agreement for cereals and cereal products (0.96), fish (0.96), and potatoes (0.99). The Spearman correlation between total scores of the WCRF/AICR dietary recommendations was 0.53.ConclusionsRelative to a 7-day dietary record, the validity of an FFQ for measuring dietary intake among survivors of CRC appeared moderate to good for most nutrients and food groups.     

The relative validity of a computerized food frequency questionnaire for estimating intake of dietary iron and its absorption modifiers

OBJECTIVE: To determine the relative validity of an iron food frequency questionnaire (iron FFQ) designed to assess intakes of dietary iron and its absorption modifiers. DESIGN: A computer-administered food frequency questionnaire was designed to estimate intake of total, non-haem, haem and meat iron as well as dietary components which influence iron absorption (vitamin C, phytate, calcium, grammes of meat/fish/poultry, tea and coffee) in women consuming a Western diet. The relative validity of the iron FFQ was assessed by comparing its results with those from weighed diet records collected over 11 days. SETTING: Dunedin, New Zealand. PARTICIPANTS: Forty-nine women aged 19-31 y attending the University of Otago. RESULTS: There was good agreement between the iron FFQ and the weighed diet records for median intakes of total iron, non-haem iron, calcium, tea and coffee. For dietary component intakes, correlations between the two methods ranged from 0.39 (for vitamin C) to 0.87 (for coffee) with 0.52 for total iron, and 0.61 for haem iron. In cross-classification with the weighed diet record, the iron FFQ correctly classified between 22% (for vitamin C) and 51% (for phytate) of participants into the same quartile. Actual values for surrogate categories indicated that the questionnaire can clearly differentiate between low and high intakes of all the dietary components assessed. The questionnaire also showed an acceptable level of agreement between repeat administrations (eg a correlation for total iron of 0.65). CONCLUSIONS: The iron FFQ is appropriate for assessing group intakes of total iron, and iron absorption modifiers, in population studies to assess the aetiology and treatment of iron deficiency states in adult women consuming a Western diet. SPONSORSHIP: This research was supported (in part) by a grant from the Health Research Council of New Zealand.     

Validation of a food frequency questionnaire for assessing dietary nutrients in Brazilian children 5 to 10 years of age

OBJECTIVE: This study aimed to assess the relative validity of a food frequency questionnaire (FFQ), previously validated to measure usual intakes in adults, for measuring dietary intakes in children 5 to 10 y of age. METHODS: Dietary intakes were measured using an FFQ and a 3-d dietary record. Healthy children, 5 to 10 y old (n = 151), were recruited from public schools and asked to answer the questions in the FFQ and to provide non-consecutive 3-d dietary records based on reported estimated portion sizes. Paired sample t tests and Pearson's correlation coefficients were conducted to determine whether the two instruments reported similar values for energy and nutrients. The agreement of quartile categorization between the two instruments was also examined. RESULTS: Estimated energy and nutrient intakes derived from the FFQ were significantly higher than those derived from 3-d dietary records. As expected, Pearson's correlations increased after adjusting for residual measurement error, presumably due to exclusion of the high within-person variability in intake of these nutrients. Moderate to high (r > 0.50) correlation coefficients were verified for some nutrients such as calcium, folate, vitamin B2, vitamin A, and vitamin C. CONCLUSION: This FFQ, originally developed for use in adults, appears to overestimate usual energy and nutrient intakes in children 5 to 10 y of age. Further work is necessary to conduct a calibration study to establish adequate portion sizes before instrument adoption in this population.     

Disagreement of energy and macronutrient intakes estimated from a food frequency questionnaire and 3-day diet record in girls 4 to 9 years of age

BACKGROUND: The Block98 food frequency questionnaire (FFQ) has been validated for dietary assessment of usual intakes in adults, but not in children. OBJECTIVE: To assess the agreement of the Block98 FFQ and 3-day diet records for measuring dietary intakes in young girls. SUBJECTS/SETTING: Healthy 4- to 9-year-old girls (N=61; 6.5+/-1.6 years) were recruited from the Athens/Clarke county area in Georgia. DESIGN: Dietary intakes were measured using the Block98 FFQ and 3-day diet records, with nutrient analysis of the 3-day diet records conducted using the Food Processor computer program (ESHA; version 7.21, 1998, ESHA Research, Salem, OR). The Block98 FFQ was completed by a trained interviewer and parent, with input from the child, if able. Food models and portion size pictures were used to increase reporting accuracy. STATISTICAL ANALYSIS: Paired sample t tests and simple regression were conducted to determine whether the two diet instruments reported similar values for energy and macronutrients. RESULTS: Block98 FFQ overestimated intakes from 3-day diet records for energy (2,180+/-692 vs 1,749+/-328 kcal), protein (68.3+/-25.9 vs 57.9+/-14.8 g/day), carbohydrate (298.7+/-97.0 vs 244.7+/-46.1 g/day) and fat (83.6+/-30.5 vs 62.3+/-14.7 g/day) (P<.05). Furthermore, the nutrients assessed using the two different methods were only moderately correlated (range: r=0.40 to 0.55). APPLICATIONS/CONCLUSIONS: The Block98 FFQ agreed weakly to moderately with the 3-day diet records, and resulted in consistently higher intakes of all nutrients. These findings suggest that additional work is needed to develop a FFQ that reflects young children's energy and macronutrient intakes.     

Validity and Reproducibility of a Food Frequency Questionnaire to Assess Macro and Micro-Nutrient Intake among a Convenience Cohort of Healthy Adult Qataris

This study aimed at developing a valid culture-sensitive quantitative food frequency questionnaire (FFQ) for Qatari adults. A convenient sample of healthy Qataris (n = 107) were recruited from family members of Qatar University students. The Diet History Questionnaire II of the US National Cancer Institute was translated to Arabic language, back-translated to English, pilot tested, and then modified accordingly to be used in Qatari setting. Participants were asked to complete the translated version of the FFQ. This FFQ was then validated against three 24 h diet recall (24 hDR) including a weekend day. Participants were asked to complete the FFQ again after one-month period to measure its repeatability. Dietary data were analyzed using the dietary analysis software ESHA. The validity and reliability of FFQ were assessed by comparing the median intake of nutrients and foods and by calculating the Pearson correlation coefficients. The median nutrient intakes assessed by the second FFQ were higher than that reported in the baseline FFQ1 except for fat. The percentage of increase varies between 1.5% and 96%. Results of the second FFQ indicated an overestimation of intake for most nutrients (macro and micro). Macronutrient intakes assessed by the two FFQ and 24 hDR were strongly correlated. The correlation coefficients for micronutrient intakes between FFQ2 and 24hDR were lower than that of the two FFQs except for calcium (r = 0.55) and sodium (r = 0.643). They ranged from (−0.17) for fluorine to (0.643) for sodium. The agreement rates for classifying macronutrient intakes into same or adjacent quartile were between 79.4% and 100% for the two FFQs and between 71% and 100% for the second FFQ and 24hDR. The reported consumption of food groups estimated by FFQ2 was significantly higher than that reported by FFQ1. In conclusion, the developed FFQ was sufficiently valid to assess energy and macronutrients but not micronutrients. The reliability was adequate for most nutrients.     

Nutrient Database Development: A Historical Perspective from the Framingham Nutrition Studies

Food frequency questionnaires (FFQs) are commonly used in nutritional epidemiology to assess habitual eating habits. Development of an appropriate food and nutrient database is required for translating information derived from FFQs into estimates of nutrient intake, dietary quality, or for absolute or rank-ordered nutritional risk assessment. We discuss the procedures used recently in designing a historical nutrient database to analyze an FFQ administered in 1984-1988 to Framingham Offspring-Spouse Study members. This systematic approach should inform other research in the field. The self-administered 145-item Framingham FFQ is semi-quantitative with seven nonoverlapping response categories to determine annual consumption frequency. The database development process included selection of the US Department of Agriculture's Nutrient Database for Standard Reference as the primary raw data source, expansion of the 145 FFQ line items to code individual foods to assign nutrient values, a selection process to match foods to appropriate nutrition codes for nutrient information, and a statistical model to calculate nutrient intakes. The historical database contains 449 foods and nutrient data for all 29 nutrients available in 1985. The adequacy with which an FFQ can provide reliable diet assessment data depends on the integrity of the underlying database. We outlined a systematic protocol to derive usual dietary intake from an FFQ using a robust nutrient database that is appropriate for the Framingham Offspring-Spouse Study FFQ and its assessment time-frame. The database can be updated to accommodate changes in the food supply and eating behaviors and creates a foundation for future nutrition research.     

Validity of a food frequency questionnaire varied by age and body mass index

BACKGROUND AND OBJECTIVE: The validity of food frequency questionnaires (FFQs) in measuring food consumption and nutrient intake has to be assessed. The objective of this study was to assess the validity of a 128-item FFQ in specific subgroups of Finnish adults. METHODS: The study included 294 subjects (137 men and 157 women). A 3-day food record was used as the reference method. RESULTS: The mean intake of all nutrients except alcohol was higher measured with the FFQ than with the food records. In general, the Pearson correlations for energy adjusted nutrients between the FFQ and the food records were higher in women than in men. The correlations ranged from 0.14 (retinol) to 0.66 (fiber and alcohol) in men, and from 0.20 (long-chain n-3 fatty acids) to 0.70 (alcohol) in women. The results in subgroups showed that measuring nutrient intakes is more difficult among younger (30-50 years) women and overweight men and women than among others. CONCLUSIONS: The study showed that the FFQ is a useful tool in epidemiologic studies in measuring the diet of Finnish adults given that the problems among specific subgroups are taken into account in interpretation.