Reproducibility and validity of a Chinese food frequency questionnaire used in Taiwan

A 64-item Chinese food frequency questionnaire (FFQ) combined with open questions on types of staples and cooking oil most frequently consumed was designed for a prospective study in Taiwan to appraise participants' usual intake. We examined its reproducibility and validity. The form was administered three times at three-month intervals by face-to-face interview to 83 senior college students majoring in nutrition, in order to recall their usual dietary intake over the past six months. They also completed five-day (includes both weekends) diet records (DR) after each interview. Averaged intake levels of most nutrients assessed by the three FFQs were slightly higher than those of 15-day DR. Intraclass correlation coefficients for nutrient intakes assessed by three FFQs three months apart ranged from 0.37 for saturated fat to 0.82 for alcohol (average: 0.52). Averaged Pearson correlation coefficients between the unadjusted and energy-adjusted nutrient intakes measured by DR and by the third FFQ (which asked about diet during the six months encompassing the diet records) were 0.40 and 0.35, respectively, not including vitamins A and C. These correlations were higher (average: 0.47) after adjusting for the daily variation of the diet records. On average, 50% subjects were correctly classified into the same tertiles by both methods; 11% of the subjects were misclassified to extreme categories. These data indicate that this FFQ for Chinese-speaking people in Taiwan is reproducible and provides a useful measure of intake for many nutrients over a six-month period.     

Validity and reproducibility of the food frequency questionnaire used in the Shanghai Women's Health Study

To evaluate the validity and reliability of the food frequency questionnaire (FFQ) used in the Shanghai Women's Health Study (SWHS), 200 SWHS participants were recruited for a dietary calibration study. Study participants completed an FFQ at baseline and 24-h dietary recalls (24-HDR) twice per month consecutively for 12 months. At the end of the study, a second FFQ was administered. Of the 200 study participants, 196 completed 24 or more days of 24-h dietary recalls, 191 completed two FFQs from whom the results of this report were based. The FFQ included the foods that accounted for 86% of the foods recorded in the 24-HDR surveys. Validity of the FFQ was evaluated by comparing intake levels of major nutrients and foods obtained from the second FFQ with those derived from the multiple 24-HDR. The median intake for major nutrients, rice, poultry and meat derived from the second FFQ and the 24-HDR was similar, with the differences ranging from 1.3 to 12.1%. The FFQ tended to overestimate the intake level of total vegetables and total fruits, and the differences were explained mainly by over-reporting seasonal vegetables and fruits consumption in the FFQ. Nutrient and food intake assessed by the FFQ and the multiple 24-HDR correlated very well, with the correlation coefficients being 0.59-0.66 for macronutrients, 0.41-0.59 for micronutrients, and 0.41-0.66 for major food groups. The reliability of the FFQ was assessed by comparing the correlation and median intake of nutrients and food groups obtained from the two FFQs that were administered approximately 2 y apart. The median intake levels for selected nutrients and food groups derived from the two FFQs were similar with differences below 10%. At the individual level, the intake levels of these dietary variables obtained from two FFQs also correlated well. When nutrient and food group intakes were categorized into quartiles, FFQ and 24-HDR produced exact agreement rates between 33 and 50%. Misclassification to adjacent quartile was common, ranging from 34-48%, while misclassification to an extreme quartile was rare (1-6%). These data indicate that the SWHS FFQ can reliably and accurately measure usual intake of major nutrients and food groups among women in Shanghai.     

Validity and reproducibility of a semi-quantitative food frequency questionnaire for use among pregnant women in rural China

A longitudinal study was conducted to validate a 68-item semi-quantitative food-frequency questionnaire (FFQ) for assessing nutrient intake among pregnant women in rural China. The interview administrated FFQs were conducted at the start of the third trimester (FFQ1) and repeated three months later prior to delivery (FFQ2), and compared with six repeated 24-hour recalls collected between the FFQs. From June to September 2004, 125 women at 23 to 26 weeks of gestation were recruited into the study in two rural counties in Shaanxi province, China. Pearson correlation coefficients for crude nutrients assessed by FFQ1 and FFQ2 had a mean of 0.46, and ranged from 0.31 for thiamin to 0.61 for fat. Pearson correlation coefficients estimated by FFQ2 and 24-hour recalls had a mean of 0.62 for all nutrients, and ranged from 0.53 for cholesterol and carotene to 0.70 for alpha-vitamin E and potassium. De-attenuated coefficients had a mean of 0.69 for all nutrients, and ranged from 0.58 for cholesterol to 0.77 for alpha- vitamin E. Bland-Altman plots revealed significant relationships between the difference and the average of the two methods with larger differences at higher average intakes. On average, 74% of participants were classified into the same or adjacent nutrient intake quintiles, while 1% were grossly misclassified to opposite quintiles. In conclusion, this FFQ has adequate reproducibility and validity for most nutrients but would benefit from the addition of wheat porridge to ensure it is suitable for assessing dietary intake in pregnant women in rural China.     

A Review of Food Frequency Questionnaires Developed ?and Validated in Japan

Background

The food frequency questionnaire (FFQ) has been used throughout the world for epidemiological purposes. Because dietary habits vary greatly, the FFQ must be tailored for use with specific populations. The usefulness of FFQs in Japan was assessed by reviewing questionnaires developed and validated in that country.

Methods

A literature search was conducted to identify articles on the development and/or validation of FFQs for Japanese populations. For each FFQ identified, validation studies were used to abstract its characteristics and information. The correlation coefficients between diet records (DRs) and FFQ estimates and those between the same FFQs completed twice were used to evaluate validity and reproducibility, respectively, of the questionnaires.

Results

Twenty-one eligible FFQs were identified. They were found to be reasonably valid and reproducible. The median of correlation coefficients between DRs and FFQs ranged from 0.31 to 0.56 for target nutrients, and that between the same FFQs completed twice within a period of 9 months to 1 year ranged from 0.50 to 0.72. Relatively poor validity was found for FFQ estimates on consumption of potatoes, seaweed, sodium, niacin, and polyunsaturated fatty acids. For the purpose of analysis, FFQs were divided into long FFQs (97 or more food items) and short FFQs (<70 items); the former had slightly higher validity.

Conclusion

FFQs are useful for assessing dietary intake in Japan, although careful consideration is required for the food groups and nutrients for which FFQs had low validity.Key words: food frequency questionnaire, validity, reproducibility, nutrient, food group     

Validity and Calibration of Food Frequency Questionnaires Used with African-American Adults in the Jackson Heart Study

Objective

To examine the relative validity of two food frequency questionnaires (FFQs) developed for use in investigating diet and disease relationships within the adult African-American population in the southern United States.

Design

Cross-sectional analyses of dietary nutrient intake data, comparing four 24-hour dietary recalls with an FFQ developed by the Lower Mississippi Delta Nutrition Intervention Research Initiative, and its shorter version adapted for use in the Jackson Heart Study.

Subjects

A representative subset of participants (n=499, aged 35 to 81 years) from the baseline Jackson Heart Study cohort (N=5,302) was selected for this study. Data collection took place between winter 2000 and spring 2004.

Statistical analyses

Pearson's correlation coefficients (energy adjusted and de-attenuated) for 26 nutrients estimates from each of the FFQs, comparing them with the mean of four 24-hour dietary recalls. The ability of the FFQs to rank individuals based on nutrient intakes was compared to that of the mean of four 24-hour dietary recalls and attenuation coefficients were also calculated.

Results

Median nutrient intake estimates tended to be higher on the long and lower on the short FFQ compared to the median for the mean of four 24-hour dietary recalls. Energy adjusted and deattenuated correlations of FFQ intake estimates with recalls ranged from 0.20 for sodium to 0.70 for carbohydrate for the short FFQ and from 0.23 for polyunsaturated fat to 0.75 for dietary fiber and magnesium for the long. Attenuation coefficients for men on average were 0.42 for the short and 0.49 for the long FFQ. For women, these were 0.31 for the short and 0.42 for the long FFQ.

Conclusions

Both FFQs appear to be reasonably valid for assessment of dietary intake of adult African Americans in the South. The Lower Mississippi Delta Nutrition Intervention Research Initiative FFQ exhibited higher intake estimates and stronger correlations with recalls than the Jackson Heart Study FFQ for most nutrients analyzed, more so for women than men.     

A 7-item versus 31-item food frequency questionnaire for measuring fruit, juice, and vegetable intake among a predominantly African-American population

OBJECTIVE: This study sought to determine which of 2 fruit and vegetable food frequency questionnaires (FFQs) most closely approximated intake measured by the average of four 24-hour dietary recalls. DESIGN: Participants completed either a 31-item FFQ (n = 70) or 7-item FFQ (n = 76) on 2 occasions approximately 2 weeks apart. During the interval between FFQs1 participants provided four 24-hour dietary recalls via telephone interview. SUBJECTS/SETTING: Participants were 146 persons with food preparation responsibilities in families of students in grades 3 through 5. Respondents were predominantly African-American women in Atlanta, Ga. STATISTICAL ANALYSIS: Pearson correlation coefficients of log-transformed values estimated the reliability of each FFQ and compared FFQ estimates to reference values. The intraclass correlation coefficient evaluated consistency across 24-hour recalls. RESULTS: The first FFQs overestimated intake approximately twofold. The 31-item FFQ estimates exceeded 7-item FFQ estimates by approximately 30% . Correlations with recall estimates were high for the 7-item FFQ and moderate to low for the 31-item FFQ. The second FFQ estimates were more highly correlated to reference values. From the first to the second administration, 7-item FFQ estimates dropped from 5.2 to 2.7 servings, and 31-item FFQ estimates dropped from 6.7 to 3.5 servings. Neither FFQ produced highly reliable estimates. CONCLUSIONS: Mean total fruit and vegetable consumption was closer to reference estimates for the first 7-item FFQ and the second 31-item FFQ. The 7-item FFQ correlated more highly with reference estimates than did the 31-item FFQ. Therefore, we conclude that for African-American adults, a 1-time-administered FFQ using 7 broad food categories correlates more highly with reference values than a FFQ using 31 individual fruit and vegetable items.     

Validity and reproducibility of a food frequency questionnaire for pregnant Finnish women

The authors developed a self-administered 181-item food frequency questionnaire (FFQ) to assess dietary intake during pregnancy for Finnish women from August 1995 to July 1996. In the validation study (n = 113), the data that were collected by using two 5-day food records completed during the eighth month of pregnancy were compared with FFQ data. The intake of foods and nutrients was higher as determined by FFQ than that assessed using food records. Pearson correlation coefficients for nutrients, after adjustment for energy, ranged from 0.19 (vitamin E) to 0.70 (thiamin) and, for foods, from 0.03 (high-fat milk) to 0.84 (low-fat milk). Energy adjustment improved the correlations for nutrients. Correction for attenuation improved correlations for both foods and nutrients. On average, 70% of the foods and 69% of the nutrients fell into the same or adjacent quintiles, according to the FFQ and the food record. In the reproducibility study, 111 women completed the FFQs twice at a 1-month interval. The intraclass correlation coefficients for nutrients ranged from 0.42 (ethanol) to 0.72 (sucrose, riboflavin, and calcium), and for foods, they ranged from 0.44 (ice cream) to 0.91 (coffee). The authors conclude that the FFQ has an acceptable reproducibility and represents a useful tool for categorizing pregnant women according to their dietary intake.     

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.     

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.     

Development and evaluation of a short instrument to estimate usual dietary intake of percentage energy from fat

OBJECTIVE: To describe the data-based development of a short dietary assessment instrument, a 16-item screener; and to evaluate the performance of the screener, comparing its performance with a complete 120-item food frequency questionnaire (FFQ) in assessing percentage energy from fat intake. DESIGN: A subsample (n=404) of participants in the National Institutes of Health-AARP Diet and Health Study, who had completed an FFQ and two 24-hour dietary recalls, also completed the fat screener. Percentage energy from fat from the screener and from the FFQ were compared with estimated true usual intake using a measurement error model. RESULTS: For men, the mean percentage energy from fat estimates for the different methods were: recalls, 30.1%, screener, 29.9%; FFQ, 30.4%. For women, the results were: recalls, 31.3%, screener, 28.4%, FFQ, 30.0%. Estimated correlations between true intake and screener were 0.64 and 0.58 for men and women, respectively, and between true intake and FFQ were 0.67 for men and 0.72 for women. Estimated attenuation coefficients for the screener were 1.29 (men) and 0.98 (women) and for the FFQ were 0.56 (men) and 0.57 (women). CONCLUSIONS: The percentage energy from fat screener, when used in conjunction with external reference data, may be useful to compare mean intakes of fat for different population subgroups, and to examine relationships between fat intake and other factors.     

Relative Validity and Reproducibility of a Food Frequency Questionnaire to Assess Food Group Intake in Pregnant Jordanian Women

BackgroundResearch on the relationship between maternal diet and pregnancy outcomes requires valid dietary assessment tools in pregnancy.ObjectiveThis study aimed to develop and examine the relative validity and reproducibility of a quantitative food frequency questionnaire (FFQ) to estimate food group intake in a sample of pregnant Jordanian women.DesignIn this validation study, food group intake from a culturally sensitive quantitative FFQ was compared with food group intake from three 24-hour dietary recalls.Participants and settingThe validation study was conducted from 2015 to 2017 at the maternity clinics in Jordan University Hospital among 131 healthy singleton pregnant Jordanian women. Of these women, 30 also took part in the reproducibility phase, which involved repeated completion of the FFQ in a time frame of 1 month. Pregnant women who had gestational diabetes, preeclampsia, and chronic diseases were excluded.Main outcome measuresRelative validity and reproducibility of a 117-item quantitative FFQ used to estimate usual food intake over a period of 1 month.Statistical analyses performedIntraclass correlation coefficients and weighted κ statistics were calculated to test the reproducibility between the two administrations of the FFQ. Pearson correlations were estimated to validate the FFQ against 24-hour dietary recalls. Cross-classification and Bland-Altman plots were used to examine the agreement between the two dietary assessment methods.ResultsThe intraclass correlation coefficients between the two FFQs ranged from 0.24 for legumes to 0.93 for processed meats. A moderate level of agreement was observed between two FFQs. De-attenuated and energy-adjusted correlations ranged from 0.08 for sweets and sugar to 0.93 for sugary drinks. On average, 50.9% and 45.2% of participants were classified by the FFQ and the 24-hour dietary recalls into the same quartile based on their crude and energy-adjusted food group intake, respectively. Bland-Altman plots showed satisfactory agreement between two methods for most food groups.ConclusionsThe FFQ showed moderate reproducibility and good relative validity for most food groups.     

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.     

The Anti Cancer Council of Victoria FFQ: relative validity of nutrient intakes compared with weighed food records in young to middle-aged women in a study of iron supplementation

OBJECTIVE: To assess the validity of the Anti Cancer Council of Victoria food frequency questionnaire (ACCVFFQ) relative to seven-day weighed food records (WFRs) in 63 women of child-bearing age. METHOD: 63 women completed WFRs to assess iron intake as part of a study on iron deficiency. These women also completed the ACCVFFQ. Nutrient intakes were computed independently for the WFRs and FFQs. Intakes were compared as group means, by correlation and by quintile classification, adjusting for day-to-day variation in intakes, and for energy intake. Individual differences in results were also examined. RESULTS: The strongest associations between WFR and FFQ results were energy-adjusted, log-transformed and adjusted for day-to-day variability in intake. Correlation coefficients ranged from 0.28 for vitamin A to 0.78 for carbohydrate. Mean intakes from the WFRs and FFQs were within +/- 20% for 21 of 27 nutrients. Poor agreement between FFQs and WFRs for retinol intake was due to the inclusion of liver in two WFRs, an item which is not included in the FFQ. CONCLUSION: The ACCVFFQ performs as well as other FFQs for which validation data are available. The relatively poor measurement of retinol is consistent with other data, and with the limited number of foods in which this nutrient is abundant. IMPLICATIONS: The availability of an optically scannable valid instrument for assessing dietary intake will facilitate epidemiological studies of diet and disease, an area of current research priority.     

Measurement characteristics of the Women's Health Initiative food frequency questionnaire

PURPOSE: The Women's Health Initiative (WHI) is the largest research program ever initiated in the United States with a focus on diet and health. Therefore, it is important to understand and document the measurement characteristics of the key dietary assessment instrument: the WHI food frequency questionnaire (FFQ). METHODS: Data are from 113 women screened for participation in the WHI in 1995. We assessed bias and precision of the FFQ by comparing the intake of 30 nutrients estimated from the FFQ with means from four 24-hour dietary recalls and a 4-day food record. RESULTS: For most nutrients, means estimated by the FFQ were within 10% of the records or recalls. Precision, defined as the correlation between the FFQ and the records and recalls, was similar to other FFQs. Energy adjusted correlation coefficients ranged from 0.2 (vitamin B12) to 0.7 (magnesium) with a mean of 0.5. The correlation for percentage energy from fat (a key measure in WHI) was 0.6. Vitamin supplement use was common. For example, almost half of total vitamin E intake was obtained from supplements. Including supplemental vitamins and minerals increased micronutrient correlation coefficients, which ranged from 0.2 (thiamin) to 0.8 (vitamin E) with a mean of 0.6. CONCLUSIONS: The WHI FFQ produced nutrient estimate, that were similar to those obtained from short-term dietary recall and recording methods. Comparison of WHI FFQ nutrient intake measures to independent and unbiased measures, such as doubly labeled water estimates of energy expenditure, are needed to help address the validity of the FFQ in this population.     

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.     

Evaluation of a Quantitative Food Frequency Questionnaire for 5-Year-Old Children in an Asian Population

BackgroundFood frequency questionnaires (FFQs) are often used to assess dietary intakes due to their ability to assess intake over extended periods, their low respondent burden, and their cost-effectiveness. A quantitative FFQ that includes locally appropriate food items for 5-year-old children in a multiethnic Asian population was developed, but its validity has not previously been evaluated.ObjectiveTo evaluate the relative validity of a newly developed FFQ as a dietary assessment tool for 5-year-old children in a multiethnic Asian population.DesignThe 112 –food item FFQ was administered by trained interviewers to caregivers of children. Frequency of food items consumed in the previous month and portion size information were collected. The FFQs were evaluated against 3-day nonweighed diet records (DRs) completed by caregivers.Participants/settingThe dietary data of 361 children aged 5 years from the Growing Up in Singapore Towards Healthy Outcomes mother-offspring cohort were collected in 2015-2016.Main outcome measuresNutrients of interest included energy, macronutrients, fiber, cholesterol, vitamin A, beta carotene, calcium, and iron, calculated from the FFQs and DRs.Statistical analyses performedNutrient intakes according to FFQs in relation to DRs were assessed using Pearson’s correlation, Lin’s concordance, Bland-Altman plots, quintile joint classification, and Cohen’s κ statistics.ResultsThe highest energy-adjusted correlation (Pearson’s r=0.71) and concordance (Lin’s concordance=0.69) were observed for calcium. Fiber, saturated fat, polyunsaturated fatty acids (PUFA), cholesterol, and iron also showed correlation coefficients and concordance of at least 0.40. Bland-Altman plots suggested no substantial bias across ranges of intakes for the nutrients with correlations and concordance of 0.40 or above. Quintiles joint classification showed substantial agreement for calcium (κ=0.66), and moderate agreement for iron, fiber, saturated fat, polyunsaturated fat, and beta carotene (κ=0.59, 0.54, 0.49, 0.44, 0.43, respectively).ConclusionsThe newly developed FFQ is in reasonable agreement with DR for estimating intakes of calcium, fiber, saturated fat, PUFA, cholesterol, and iron. In addition, the FFQ is able to classify children according to quintiles of nutrient intakes, with moderate to substantial quintile agreements between FFQ and DR for calcium, iron, fiber, saturated fat, PUFA, and beta carotene. To assess the remaining nutrients, DR method is recommended instead of the FFQ.     

The 72-Item Semi-Quantitative Food Frequency Questionnaire (72-Item SQ-FFQ) for Polish Young Adults: Reproducibility and Relative Validity

The food frequency questionnaires (FFQs) are the most common tools used in dietary research. Each newly developed, modified, or adapted FFQ should be validated in the target population. The aim of this study was to assess the reproducibility and relative validity of the 72-item semi-quantitative food frequency questionnaire (72-item SQ-FFQ) for Polish adults. The 72-item SQ-FFQ was developed based on a non-quantitative FFQ covering 62 food items (62-item FFQ-6®). The study was conducted among 186 university students aged 19–26 years (47.8% of females). The FFQ was administered on two occasions (FFQcrude and FFQretest) to assess the test–retest reproducibility, and the FFQcrude was compared with the estimated food record (FRcrude) to evaluate the relative validity of the FFQ in assessing the intake of energy, 38 nutrients, and alcohol. The energy intake obtained with both methods was standardized to 2000 kcal/day (FFQstand, FRstand). The dietary intake obtained with FFQcrude was adjusted using linear regression analysis (FFQreg). The reproducibility and relative validity of the FFQ were assessed by comparing the mean values of energy and nutrient intake and using Spearman’s correlation coefficient, the cross-classification analysis, and the Bland–Altman method. Spearman’s correlation coefficient between both administrations of the FFQ ranged from 0.631 to 0.878 (the intraclass correlation coefficient: 0.583–0.935), for FFQcrude and FRcrude ranged from −0.025 to 0.390, for FFQstand and FRstand ranged from 0.021 to 0.546, and for FFQreg and FRcrude ranged from 0.028 to 0.391. The percentage of respondents classified into the same or adjacent quartiles of nutrient intake obtained from two administrations of the FFQ ranged from 84.9% to 97.8%, for FFQcrude and FRcrude ranged from 61.3% to 76.9%, for FFQstand and FRstand ranged from 63.4% to 83.9%, and for FFQreg and FRcrude ranged from 60.2% to 76.9%. In conclusion, our findings showed good reproducibility and acceptable relative validity of the 72-item SQ-FFQ. This tool can be recommended for assessing dietary intake among Polish young adults. However, the intake of certain nutrients should be interpreted with caution.     

Validation of three food frequency questionnaires and 24-hour recalls with serum carotenoid levels in a sample of African-American adults

The validity of self-reported fruit and vegetable intake in minority populations has not been adequately established. In this study, the authors examined the association of three food frequency questionnaires (FFQs) and 24-hour dietary recalls with serum carotenoid levels. Approximately 1,000 African-American adults recruited from 15 churches in Atlanta, Georgia (1997-1998) completed three fruit and vegetable FFQs: a seven-item instrument assessing intake during the past month; a two-item measure assessing usual intake; and a 36-item measure adapted from the Health Habits and History Questionnaire. A total of 414 participants received a 24-hour recall by telephone, and 105 of them received two additional recalls. Serum levels of lycopene, lutein, cryptoxanthin, alpha-carotene, and beta-carotene were assessed in 813 participants and used as the validity criterion. The correlations of fruit and vegetable servings with specific and total serum carotenoid levels were generally higher for the 36-item FFQ than for the two-item and seven-item instruments. The strongest correlation of fruit and vegetable servings with total carotenoid levels was observed for the three recalls (r = 0.42), with the 36-item FFQ and the single 24-hour recall yielding comparable correlations (r = 0.35 and r = 0.37, respectively). The validity of the 36-item fruit and vegetable FFQ was generally as strong as the validity of both 1 and 3 days of recalls. Given the lower cost and time needed for administration relative to recalls, it appears that the 36-item FFQ has merit for evaluating fruit and vegetable health interventions.     

Design characteristics of food frequency questionnaires in relation to their validity

The authors investigated the role of food frequency questionnaire (FFQ) design, including length, use of portion-size questions, and FFQ origin, in ranking subjects according to their nutrient intake. They also studied the ability of the FFQ to detect differences in energy intake between subgroups and to assess energy and protein intake. In a meta-analysis of 40 validation studies, FFQs with longer food lists (200 items) were better than shorter FFQs at ranking subjects for most nutrients; results were statistically significant for protein, energy-adjusted total fat, and energy-adjusted vitamin C. The authors found that FFQs that included standard portions had higher correlation coefficients for energy-adjusted vitamin C (0.80 vs. 0.60, p < 0.0001) and protein (0.69 vs. 0.61, p = 0.03) than FFQs with portion-size questions. However, it remained difficult from this review to analyze the effects of using portion-size questions. FFQs slightly underestimated gender differences in energy intake, although level of energy intake was underreported by 23% and level of protein intake by 17%. The authors concluded that FFQs with more items are better able to rank people according to their intake and that they are able to distinguish between subpopulations, even though they underestimated the magnitude of these differences.     

Reproducibility and Validity of a Food Frequency Questionnaire (FFQ) Developed for Middle-Aged and Older Adults in Semarang,Indonesia

We assessed the reproducibility and validity of a food frequency questionnaire (FFQ) among middle-aged and older adults in Semarang, Indonesia. A total of 259 subjects aged 40–80 years completed two FFQs (nine-month apart) and nine 24 h dietary recalls (24HDRs, as a reference method). The reproducibility of the FFQ was analyzed using correlation coefficient, intra-class correlation coefficient (ICC), weighted kappa statistics and misclassification analysis. The validity was estimated by comparing the data acquired from FFQ1 and 24HDRs. The crude Pearson’s correlation coefficients and ICC for total energy and nutrients between FFQ1 and FFQ2 ranged from 0.50 to 0.81 and 0.44 to 0.78, respectively. Energy adjustment decreased the correlation coefficients for most nutrients. The crude, energy-adjusted and de-attenuated correlation coefficients for FFQ1 and 24HDRs ranged from 0.41 to 0.70, 0.31 to 0.89 and 0.54 to 0.82, respectively. The agreement rates for the same or adjacent quartile classifications were 81.1–94.6% for two FFQs and 80.7–89.6% for FFQ1 and 24HDRs. The weighted kappa values were 0.21 to 0.42 for two FFQs and 0.20 to 0.34 for FFQ1 and 24HDRs. A positive mean difference was found in the Bland–Altman analyses for energy and macronutrients. The FFQ could be acceptable for nutritional epidemiology study among Indonesians.