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.     

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 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 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.     

Assessing the validity of a food frequency questionnaire among low-income women in São Paulo, southeastern Brazil

This study describes the validity of a food frequency questionnaire (FFQ) in 93 low-income women (20-65 years), participating in a case-control study in S?o Paulo, Brazil. Two FFQ (FFQ1 and FFQ2, 12 months apart) and three 24-hour dietary recalls (24hR) were conducted between 2003 and 2004 to estimate dietary intake during the past year. The Pearson correlation coefficients (crude, energy-adjusted and de-attenuated) were used for comparisons between FFQ and 24hR. The agreement between the methods was further examined by the Bland-Altman analysis. For the assessment of long-term reliability, the energy-adjusted intra-class correlation coefficients were mostly around 0.40, but higher for vitamin A and folate (0.50-0.56). Energy-adjusted, attenuation-corrected Pearson validity correlations between FFQ and DR ranged from 0.30-0.54 for macronutrients to 0.20-0.48 for micronutrients, with higher value for calcium (0.75). There were small proportions of grossly misclassified nutrient intakes, while Bland-Altman plots indicated that the FFQ is accurate in assessing nutrient intake at a group level.     

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.     

Relative Validity and Reproducibility of a Brief-Type Self-Administered Diet History Questionnaire for Japanese Children Aged 3–6 Years: Application of a Questionnaire Established for Adults in Preschool Children

Background

Dietary intake assessment and subsequent dietary education or intervention in young children is important in decreasing prevalence of various noncontagious diseases in adulthood. Validation of diet assessment questionnaires for preschool children has just started in Japan. In this study, we rearranged the brief-type self-administered diet history questionnaire (BDHQ), a convenient diet assessment questionnaire that is widely used in a range of situations for adults, for use in children aged 3–6 years (BDHQ3y) and then validated the BDHQ3y in Japanese children.

Methods

The guardians of 61 children aged 3–4 years completed the BDHQ3y twice at an interval of 1 month, along with a 3-nonconsecutive-day diet record (DR) between the two administrations of the BDHQ3y. Dietary intakes for energy and 42 selected nutrients were estimated using both the DR and the BDHQ3y. Mean intakes estimated by the two methods were compared, and correlation coefficients were calculated. Reproducibility of the BDHQ3y estimates was investigated using intra-class correlation coefficients (ICCs).

Results

No significant differences in mean intakes estimated by the DR and the BDHQ3y were observed for one- to two-thirds of energy and examined nutrients. The median of Pearson correlation coefficients between intakes energy-adjusted by the residual method was 0.31 (interquartile range, 0.24 to 0.38). The median ICC was 0.72 (interquartile range, 0.63 to 0.76) for the crude nutrient intakes.

Conclusions

Although the BDHQ3y might be a good candidate for dietary intake assessment in Japanese preschool children, its validity is currently moderate to low. Shortcomings should be overcome by obtaining and utilizing more information about children’s dietary habits.Key words: validity, reproducibility, diet history questionnaire, Japanese, preschool children     

Relative validity of a short food frequency questionnaire for assessing nutrient intake versus three-day weighed diet records in middle-aged Japanese

BACKGROUND: Validation studies on brief food frequency questionnaires (FFQs) for measuring consumption of macro- and micro-nutrients for the general populace are not fully executed in Japan. METHODS: Two hundred and two middle-aged Japanese (73 males and 129 females) in Aichi Prefecture, Japan completed an FFQ and 3day-weighed diet records (3d-WDRs) in February 2004. We compared intakes of energy and 26 nutrients computed with the FFQ against those with the 3d-WDRs as a reference. RESULTS: Mean daily intakes of selected nutrients determined with the FFQ were generally less than those with 3d-WDRs. The ratios assessed with the FFQ vs. 3d-WDRs (minimum-median-maximum) were distributed from 0.57-0.79-1.09 for males, and 0.61-0.86-1.04 for females. De-attenuated, log-transformed and energy-adjusted Pearson's correlation coefficients between intakes of selected nutrients quantified with both devices were distributed from 0.12-0.45-0.86 and energy-adjusted Spearman's rank correlation coefficients were from 0.13-0.35-0.76, for males. The respective values for females were 0.10-0.38-0.66, and 0.11-0.34-0.47. Median percentages for exact agreement, agreement within adjacent categories, and disagreement according to quartile classification of the energy-adjusted nutrient intakes measured with both methods were 33, 74, and 5 for males, and 35, 76, and 7 for females, respectively. CONCLUSION: Satisfactorily high relative validity indices of most nutrient intakes computed with the FFQ were attained against those with the 3d-WDRs. The questionnaire therefore appears applicable for categorizing individuals according to consumption of energy and selected nutrients in dietary studies of middle-aged Japanese.     

Relative validity of the geisinger rural aging study food frequency questionnaire

Objective: To determine the relative validity of a population specific food frequency questionnaire (FFQ) and evaluate the effectiveness of the instrument for assessing nutritional risk in older adults. Design: A cross-over design with participants completing two different dietary assessment instruments in random order. Setting: The Geisinger Rural Aging Study (GRAS), a longitudinal study of over 20,000 adults living in the central, northern and eastern counties of Pennsylvania. Participants: A subset of GRAS consisting of 245 older adults (60% women) ranging in age from 70 to 95 years. Measurements: Energy and nutrient intakes were assessed from two instruments: a population specific food frequency questionnaire (FFQ) and four 24-hour dietary recalls conducted over a two week period. Results: Pearson correlation coefficients between the FFQ and dietary recalls for most nutrients were 0.5 or higher which suggests that the FFQ provided relatively valid estimates of macro and micronutrient intakes examined. Bland-Altman plots were generated to examine the agreement between instruments. Data are shown for energy, folate and zinc with close agreement at lower intakes indicative of risk for folate and zinc. Sensitivity results also showed that the FFQ was able to correctly classify individuals adequately at risk for most nutrients examined. Conclusion: This population specific FFQ appears to be a valid instrument for use in in evaluating risk for many nutrients that are of particular concern in older adults residing throughout many predominately rural counties in Pennsylvania.     

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 an interviewer-administered food frequency questionnaire in Austrian adults at risk of or with overt diabetes mellitus

Food frequency questionnaires (FFQs) provide an inexpensive tool for dietary assessment. Given the scarcity of data on their validity for nutritional analysis in persons with overt diabetes mellitus or with increased risk of diabetes (relatives of patients with diabetes), this study tests the hypothesis that an FFQ, adapted to local dietary habits, yields a reliable estimate of nutrient intake when compared with 7-day food record (7DR) in healthy, prediabetes, and diabetes cohorts. One hundred three volunteers (50 persons with overt diabetes mellitus, 24 relatives of patients with diabetes, and 29 nondiabetic individuals without a family history of diabetes) completed both FFQ and 7DR. A second FFQ was completed by 100 of these volunteers after 3 months to evaluate its reproducibility. Data were compared by correlation and Bland-Altman analyses. Across the entire group, estimates for gram intakes of nutrients and total energy were associated with wide limits of agreement between FFQ and 7DR (correlation coefficients, 0.23-0.72; P < .02). Compared with 7DR, the FFQ overestimated intakes of saturated fat in the entire group (+6.6 ± 14 g; P < .001) and in persons with overt diabetes mellitus (+7.6 ± 15 g; P < .001) but underestimated protein intake in relatives of patients with diabetes (−16.36 ± 31 g; P = .01). The repeated FFQ revealed variable agreement (correlation coefficients, 0.34-0.72; P < .001) and underestimated (P < .01) macronutrient and total energy intakes, with slightly better performance in persons with overt diabetes mellitus and relatives of patients with diabetes than in nondiabetic individuals without a family history of diabetes. Hence, the FFQ allows measuring intakes of total energy and macronutrients in prediabetes and diabetes cohorts but reveals limitations when assessing dietary composition.     

Relative validity of a food-frequency questionnaire developed to assess food intake of schoolchildren living in the Brazilian Western Amazon

This study aimed to assess the relative validity of a food frequency questionnaire (FFQ) developed to assess food intake of schoolchildren from the Brazilian Western Amazon. The dietary intakes of 61 schoolchildren, aged between six and nine 9 years, were measured using two 24-hour dietary recalls and one FFQ, conducted with the children's, mother or guardians. Validity of the FFQ compared to the mean of the two dietary recalls was assessed using Pearson's correlation coefficient adjusted for attenuation and energy intake, Bland & Altman plots and evaluation of agreement levels between the two assessment methods. Energy-adjusted and deattenuated correlation coefficients ranged from -0.03 for vitamin C, to 0.93 for calcium. The mean coefficient was 0.46. The mean proportion of subjects classified within one quintile by the two methods was 66%. The Bland & Altman plots indicated good agreement for almost all nutrients, with a mean limit of agreement of 108%. These results indicate that, although there was a lack of accuracy for certain nutrients, such as vitamins A and C, the FFQ ensures reliable estimates of intake of most nutrients.     

Comparison of dietary assessment methods in a low-fat dietary intervention program

The food frequency questionnaire (FFQ) is commonly utilized for assessment of dietary fat intake, but its validity among individuals following a low-fat diet is unclear. We evaluated the agreement of nutrient estimates derived from FFQ, 24-h recall, and 3-day food records obtained from 104 participants in a randomized trial of a low-fat dietary intervention for women at elevated breast cancer risk. Comparisons were made for total calories, percent calories from fat, and total fat after 1 yr. Correlation was assessed using standard methods based on a null hypothesis of no agreement between instruments as well as by a methodology based on a null hypothesis that the instruments should be in agreement. With the use of standard methods, FFQ estimates for women on the low-fat diet were significantly correlated to records only for percent calories from fat (r = 0.39), whereas recall and record estimates were significantly correlated for all three dietary variables. Using the new method, we found no significant correlation between FFQ and either recalls or records for women following a low-fat diet but significant correlation between recall and record estimates for total calories (r = 0.67). Traditional correlation testing may overestimate the extent of agreement in dietary instruments among women on a low-fat diet. We found empirical support for the nontraditional method.     

Fitting portion sizes in a self-administered food frequency questionnaire

For epidemiological studies, a simple semiquantitative FFQ was developed to assess the frequency of intake of food items demonstrated with graphically displayed portion sizes. As a validation study, a random sample of 393 participants in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study completed 2 unannounced 24-h dietary recalls (24HDR) and the FFQ during 1 y. To calculate food and nutrient intakes, we compared the use of fitted portion sizes with the use of predefined portion sizes. Fitted portion sizes were calculated by summing food intakes over the 2 24HDR and dividing the sum by the frequency of intake reported in the FFQ for each FFQ food item, leading to similar mean intakes for FFQ and 24HDR. As predefined portion sizes, amounts that had been used in previous dietary assessments in EPIC-Potsdam were used. Mean intake of 12 food groups was 102% for men or women with fitted portion sizes and 79% for men and 95% for women with predefined portion sizes of intake measured with 2 24HDR. However, deattenuated, energy-adjusted correlation coefficients between FFQ and 24HDR were not better for 19 nutrients by the use of fitted portion sizes, with a mean correlation coefficient of 0.53 for men and 0.56 for women. Mean correlation coefficients for food groups also were similar for fitted and predefined portion sizes. Fitting portion sizes using recent reference data from a random sample of study participants improved the quantitative assessment of food and nutrient intake, but not ranking of study participants, compared with predefining portion sizes based on prior knowledge.     

Validation of a Short Food Frequency Questionnaire to Measure Dietary Intake of a Selection of Micronutrients in Oncology Patients Undergoing Systemic Therapy

Dietary intake, specifically consumption of anti-inflammatory micronutrients, can play a role in both cancer initiation as well as the treatment-related outcomes experienced by patients receiving systemic cancer therapy. Increasing research is being conducted to determine whether micronutrient supplementation can aid in altering the tumor microenvironment (TME), reducing inflammatory side effects and immune-related adverse events (irAEs). However, further research pertaining to the adequacy of dietary micronutrient intake is indicated in the oncology cohort. Currently, no tool measuring dietary intakes of various micronutrients exists in the oncology population. In this study, a 21-item food frequency questionnaire (FFQ) measuring intakes of 14 different micronutrients was validated using diet history as the reference method in 112 oncology patients. Bland Altman plot and Passing Bablok regression analysis were conducted to determine agreement between the two methods. The results showed adequate agreement between FFQ and diet history for 12 nutrients including copper, iron, vitamins A, E, and D, alpha linolenic acid (ALA), long-chain omega 3 fatty acids (LC n3-FA), arginine, glutamic acid, isoleucine, leucine, and valine. This 21-item FFQ, which takes an average of 10 min to complete, can be utilized as a quick screening tool to determine adequacy for 12 different micronutrients in place of a diet history.     

Dietary assessment instruments for preschool children: reliability of parental responses to the 24-hour recall and a food frequency questionnaire

Nutrient intakes of preschool-age children were assessed with a 24-hour dietary recall and a 3-month food frequency questionnaire (FFQ). Parents of 55 preschoolers (mean age = 4.25 +/- 0.59 years) completed the recall and FFQ on two occasions 1 week apart. The recalls and FFQs were analyzed for energy, cholesterol, protein, total carbohydrate, calcium, sodium, potassium, and saturated, polyunsaturated, and monounsaturated fats; each nutrient was expressed as raw value, value per kg body weight, and value per 1,000 kcal. Test-retest reliability estimates for the 24-hour recall indicated significant variability in reported total energy intake, but stable reports of intake were observed for one or all units of expression for polyunsaturated fats, cholesterol, protein, total carbohydrate, calcium, and potassium. The FFQ showed significant positive test-retest reliability estimates for all nutrients for all units of expression. Comparison of the recall and FFQ data showed similar percentages of intakes of energy from fat, carbohydrate, and protein and significant correlations for reported intakes of cholesterol, protein, calcium, and potassium. Comparison of the recall and FFQ data with recall data from a comparable cohort showed lower reported intakes for our sample, with the exception of protein, carbohydrate, calcium, and potassium. If validation studies are successful, the FFQ may be useful in epidemiological studies of preschoolers' intakes over extended periods. The recall may prove to be a useful tool in the assessment of day-to-day variations in macronutrient intakes.     

Relative validity of adolescent dietary patterns: a comparison of a FFQ and 3 d food record

Interest in empirically derived dietary patterns has increased over the past decade. However, relatively few studies have evaluated dietary patterns using different dietary methods, or in young populations. We quantitatively compared dietary patterns from a FFQ with those from a 3?d food record (FR) in a cohort of adolescents. Subjects from the Western Australian Pregnancy Cohort (Raine) Study completed a semi-quantitative FFQ and a 3?d FR at 14 years of age (n 783). Major dietary patterns were identified using exploratory factor analysis on thirty-eight food groups. Dietary pattern z-scores were compared using 95?% limits of agreement (LOA) and Spearman's r. Two major dietary patterns were identified in the FFQ and FR: a 'Healthy' pattern, which was high in fresh fruit, vegetables, whole grains and grilled or canned fish, and a 'Western' pattern, which was high in take-away foods, confectionery, soft drinks, crisps and fried potato. The nutrient profiles of these dietary patterns were similar when estimated by the FFQ and FR. The LOA between dietary pattern scores from the FFQ and FR were -?1·69 to 1·75 ('Healthy') and -?1·89 to 1·82 ('Western'). Minor differences in agreement were observed when boys and girls were analysed separately. Spearman's correlation coefficients between the FFQ and the FR were r 0·45 ('Healthy') and r 0·36 ('Western'). Comparable dietary patterns may be obtained from the FFQ and FR using exploratory factor analysis. This supports the use of major dietary patterns identified using the FFQ in this adolescent cohort.     

Validity and reproducibility of a self-administered food-frequency questionnaire to assess isoflavone intake in a japanese population in comparison with dietary records and blood and urine isoflavones

Valid food-frequency questionnaires (FFQ) need to be developed to assess isoflavone intake in investigations of its possible association with the lower incidence of breast and prostate cancer in Asian countries. We investigated the validity and reproducibility of isoflavone (daidzein and genistein) intakes from self-administered semiquantitative FFQ used in the JPHC Study (Japan Public Health Center-based Prospective Study on Cancer and Cardiovascular Diseases). We also investigated the number of food items that would be sufficient to ensure validity and reproducibility. We collected FFQ, dietary records (DR), blood and urine samples from 215 subjects among JPHC Study participants, estimated isoflavone intakes from FFQ and DR, and measured serum isoflavone concentration and urine isoflavone excretion. For daidzein, mean intakes estimated from FFQ and DR, serum concentration and urine excretion were 18.3 mg/d, 14.5 mg/d, 119.9 nmol/L and 17.0 micromol/d and for genistein, 31.4 mg/d, 23.4 mg/d, 475.3 nmol/L and 14.2 micromol/d, respectively. Results were similar when analyzed by sex. Spearman correlation coefficients for daidzein of energy-adjusted intakes from FFQ with those from DR, serum concentration and creatinine-adjusted urinary excretion were 0.64, 0.31 and 0.43, respectively. Correlations between two FFQ estimates with a 1-y interval were 0.76. Results were similar for genistein. The shorter version of the FFQ with three items (natto, miso and tofu for miso soup) showed a similar correlation. The original FFQ and the shorter versions have sufficient validity and reproducibility to be used in epidemiologic studies.     

Validation and reproducibility of food frequency questionnaire for Korean genome epidemiologic study

OBJECTIVE: To evaluate validity and reliability of the food-frequency questionnaire (FFQ) developed for the Korean Genome Epidemiologic Study (KoGES). METHODS: FFQ was administered twice at 1-year interval (first FFQ (FFQ1) at the beginning and second FFQ (FFQ2) at the end of the study) and diet records (DRs) were collected for 3 days during each of the four seasons from December 2002 to May 2004 for those who attended the health examination center. At the end of the study period, we collected the 12-day DRs of 124 participants. The nutrient intakes from the DRs were compared with both FFQ1 and FFQ2. RESULTS: The intakes of energy and some nutrients estimated from FFQ1 and FFQ2 were different from those assessed by the DRs. Especially, the consumption of carbohydrates was higher in FFQ1 and FFQ2 than in the DRs. The de-attenuated, age, sex and energy intake adjusted correlation coefficients between the FFQ2 and the 12-day DRs in Korean population ranged between 0.23 (Vitamin A) and 0.64 (carbohydrate). The median for all nutrients was 0.39. The correlations were similar when we compared nutrient densities of both methods. Joint classification of calorie-adjusted nutrient intakes assessed by FFQ2 and 12-day DRs by quartile ranged from 25.8% (vitamin A) to 39.5% (carbohydrate, iron) for exact concordance. Except vitamin A, the proportion of subjects classified into distant quartile was less than 7% in all nutrients. The median of correlations between the two FFQs 1 year apart were 0.45 for all nutrient intakes and 0.39 for nutrient densities. CONCLUSIONS: We conclude that the FFQ we have developed appears to be an acceptable tool for assessing the nutrient intakes in this population. Further studies for calibration of the FFQ collected from multicenters participating in the KoGES are needed. SPONSORSHIP: This study was supported by the budget of the National Genome Research Institute, Korea National Institute of Health (2002-347-6111-221).     

基于在校大学生在线24小时膳食问卷调查数据有效性研究

目的 在接受高等教育的人群中验证在线24h膳食调查问卷(ODQ)相较于面对面24h膳食调查(FDR)膳食数据的有效性。方法 采用整群随机抽样的方法,抽取四川大学142名在校大学生,在同一天之内分别进行ODQ及FDR调查。通过计算ODQ与FDR间膳食摄入的个体平均差异、Spearman相关系数、交叉表一致性检验,Bland-Altman图等方法,评价两种方法之间膳食能量及常见营养素摄入量的相关性和一致性。结果 ODQ法估计的膳食能量及营养素摄入量均低于FDR(P<0.05)。 两方法各膳食摄入量间的秩相关系数在0.54~0.74之间(P<0.05),两方法间膳食能量及营养素摄入被分类到相同或相邻的四分位数组的比例从维生素A的82.4%到维生素PP的93%,而被错误分类的比例均在5%以下,加权kappa系数分布在0.41~0.64间,呈现中度到高度的一致性。Bland-Altman图表明两方法间膳食能量及各营养素摄入呈现良好的一致性。结论 本研究表明在线24h膳食问卷在群体水平上调查大学生膳食能量和营养素摄入时具有良好的有效性。