Validation of a short food frequency questionnaire to assess folate intake

A short quantitative food frequency questionnaire (FFQ) to assess folate intake was developed and validated against a 7-d weighed food intake record (7d-WR) and biochemical indices of folate status. Thirty-six men and women completed the self-administered FFQ on two occasions a month apart, kept a 7d-WR and gave two fasting blood samples at the beginning and end of the study for measuring serum and erythrocyte folate, respectively. Mean folate intakes were similar by repeat FFQ and correlated strongly (r 077 and r 072, P<0.001, for men and women, respectively). All other comparisons were done using the results of the FFQ administered on the first occasion. Men reported similar folate intakes on the FFQ and 7d-WR, but women reported greater intakes on the FFQ compared with the 7d-WR (P<0.05). There was a statistically significant correlation (partial, controlling for gender) between folate intakes reported by FFQ and 7d-WR (r 0.53, P<0.01). Folate intakes estimated by FFQ correlated significantly with serum (r 0.47, P<0.01), but not erythrocyte folate (r 0.25, P>0.05), the strength of the association was greater in men than in women. Validity coefficients estimated using the method of triads were higher for the FFQ than for the 7d-WR when serum folate was used as the biomarker. Overall, these results suggest that this short FFQ is a useful method for assessing folate intake, particularly in men.     

Validation of a food frequency questionnaire to assess macro- and micro-nutrient intake among South Asians in the United Kingdom

Summary.Background: The South Asian population is one of the largest minority ethnic groups in the United Kingdom (UK), forming 2.7% of the UK population. Risk of diseases such as CHD, NIDDM is high in South Asians and risk of cancer low in this population compared both to the native UK population and other migrant groups. It is useful to investigate the experience of disease and dietary exposures for aetiological clues in South Asians. The FFQ was designed for a population-based case-control study of diet and breast cancer.Aims: To validate a food frequency questionnaire (FFQ) to assess macro- and micronutrient intake among South Asians in the United Kingdom (UK).Methods: A one-year long study of current diet was conducted using monthly telephone 24-hour recalls followed by administration of an interviewer-administered FFQ to ascertain usual diet during this period. General practices in the Thames and West Midlands regions, England were used to sequentially recruit 100 women from a larger random sample of South Asian migrants from general practitioners patient lists participating as controls in a case-control study of diet and breast cancer.Results: A total of 133 women were invited to achieve the final sample of 100 (76% response rate). The proportion of individuals classified by the two dietary assessment methods into the same or adjacent quartiles was high ranging from 65% (vitamin A) to 96% (protein). Misclassification into opposite quartiles was very low (0 % to 5 %), except for vitamin A (10 %). Energyadjusted Spearman correlation coefficients were reasonable for almost all nutrients being highest for protein (0.76), NSP (0.71), folate (0.70) and cholesterol (0.69). Correction for within-person variation in monthly 24-hour recalls had little effect on the magnitude of the nutrient correlations between the FFQ and the 24-hour recalls. Calibration coefficients to correct relative risks for nutrient-disease associations were above 0.50 for most nutrients indicating that the degree of attenuation introduced by the FFQ would be acceptable.Conclusions: This FFQ was specifically designed for South Asian women in the UK. Despite the diversity of diets, the FFQ had reasonable validity. The role of diet in breast cancer disease aetiology in this population is being assessed with this instrument.Sponsorship: The study was supported by Cancer Research UK.     

Relative validity of a food frequency questionnaire used to assess food intake during a dietary intervention study

To develop a cost-effective alternative for evaluating dietary intake in large-scale intervention trials of cancer and cardiovascular disease outcomes, we designed and validated a semiquantitative food frequency questionnaire (FFQ). We collected 6 to 8 of the 24-hr dietary recalls from 87 adults (ages 30-72 yr) who were randomly assigned to a walnut-supplemented diet or a control diet in a 6-mo dietary intervention trial. Relative validity of a 171-item FFQ in assessing intake of selected foods and the prescribed intervention (intake > or =25 g/day or intake < 2 g of walnuts) was determined using 24-h dietary recalls as the reference. De-attenuated correlations between FFQ and dietary recalls were .82 for walnuts, .80 for fruits, .79 for grains, .77 for vegetables, .63 for water, .44 for sweets, and .36 for dairy/eggs. High within-person variation did not allow de-attenuation for the remaining foods, but uncorrected correlations were high (> .7) for the beverage variables. The FFQ correctly classified 86 out of 87 subjects in the 2 prescribed intervention groups. The FFQ can provide an accurate measure of a food-based intervention (i.e., walnut supplementation) in a trial setting and can also accurately estimate a number of other food groups consumed during the trial.     

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.     

Validation of a food frequency questionnaire by direct measurement of habitual ad libitum food intake

Food frequency questionnaires are commonly used to assess habitual food intake. Although food frequency questionnaires are known to produce measurement error, the amount of error and effectiveness of correction methods are poorly understood. Twelve men from the Baltimore, MD/Washington, DC, area consumed an ad libitum diet for 16 weeks during the spring of 2001. At the end of the study period, subjects reported their food intakes with a food frequency questionnaire (Block 98). During weeks 8 and 16, subjects were dosed with doubly labeled water and maintained physical activity logs. Absolute and relative macronutrient intakes were poorly predicted by the food frequency questionnaire. The application of a single, group mean energy adjustment (using doubly labeled water or physical activity) reduced the variance of carbohydrate intake and increased the variance of fat and protein intakes, but none significantly (p>0.05). Subject-specific energy adjustments reduced the variance for carbohydrate and protein intakes (p<0.05). Including a body weight adjustment reduced the variance in fat intake (p<0.05) when doubly labeled water was used to first correct energy intake. The application of correction methods based on energy expenditure and body weight can be used to reduce measurement error, improving the ability of the food frequency questionnaire to measure food intake.     

Validation of a questionnaire assessing food frequency and nutritional intake in Greek adolescents

The aim of the study was to develop and validate a specific semi-quantitative food frequency questionnaire to assess nutritional intake of Greek adolescents. The sample of the study consisted of 250 pupils (15.3 +/- 0.7 years), who completed the Youth Adolescent Food Frequency Questionnaire enriched with 22 Greek foods and recipes to include ethnic and racial diversity. A 3-day weighed food recall was used as the criterion to test the validity of the questionnaire. The analysis of correlation revealed significant correlations between the two methods for almost all variables. The Pearson's coefficients ranged from 0.83 for energy intake to 0.34 for folate intake. Non-significant correlations were found for selenium and vitamin D intakes. The findings of the study provide evidence for the validity of the scale and its utility in assessing nutritional intake of Greek adolescents.     

Validation of three food frequency questionnaires to assess dietary calcium intake in adults

OBJECTIVE: To assess the accuracy of three self-administered food frequency questionnaires (FFQs) to measure dietary calcium intake in healthy adults. DESIGN: Estimates of dietary calcium intake from one previously validated and two recently developed FFQs were compared with those from 7-day food records. SUBJECTS/SETTING: Healthy adults enrolled in an outpatient study of calcium supplementation completed the 36-page Dietary History Questionnaire (DHQ), a 3-page Calcium Questionnaire, and a 1-page Short Calcium Questionnaire. Subjects then completed a 7-day food record. MAIN OUTCOME MEASURES: Differences between calcium intake reported on FFQs and calcium intake from food records were compared. STATISTICAL ANALYSES: Spearman correlations were used to measure associations among variables; Bland-Altman pairwise comparisons were conducted to assess systematic and magnitude biases. RESULTS: We studied 341 subjects, 74.5% female, mean (+/-standard deviation) age of 38+/-11 years and body mass index (calculated as kg/m(2)) of 31.8+/-7.1. Mean (+/-standard deviation) food record calcium intake was 896+/-380 mg/day; data from all three FFQs were positively related to food record calcium intake, but accounted for <40% of the variance in food record dietary calcium intake (DHQ: r(2)=0.21; Calcium Questionnaire: r(2)=0.33; Short Calcium Questionnaire: r(2)=0.37; all P<0.001). The DHQ underestimated daily calcium intake (systematic bias: -94 mg/day, P<0.001; magnitude bias r=-0.40; P<0.001), whereas the Calcium Questionnaire overestimated calcium intake (systematic bias +177 mg/day, P<0.001), but had no significant magnitude bias (r=-0.09; P=0.11). The Short Calcium Questionnaire showed minimal systematic bias (+34 mg/day, P=0.09), but had magnitude bias (r=-0.33; P<0.001). CONCLUSIONS: All three FFQs performed reasonably well at estimating dietary calcium intake compared to food records; each may be appropriate for use in select clinical and research settings.     

Validation of a questionnaire assessing food frequency and nutritional intake in Greek adolescents

The aim of the study was to develop and validate a specific semi-quantitative food frequency questionnaire to assess nutritional intake of Greek adolescents. The sample of the study consisted of 250 pupils (15.3±0.7 years), who completed the Youth Adolescent Food Frequency Questionnaire enriched with 22 Greek foods and recipes to include ethnic and racial diversity. A 3-day weighed food recall was used as the criterion to test the validity of the questionnaire. The analysis of correlation revealed significant correlations between the two methods for almost all variables. The Pearson's coefficients ranged from 0.83 for energy intake to 0.34 for folate intake. Non-significant correlations were found for selenium and vitamin D intakes. The findings of the study provide evidence for the validity of the scale and its utility in assessing nutritional intake of Greek adolescents.     

Validation of a semiquantitative food frequency questionnaire to assess energy and macronutrient intakes of Cuban Americans

OBJECTIVE: To assess the validity of a 131-item semiquantative food frequency questionnaire (FFQ) by comparison with multiple food records in Cuban Americans. DESIGN: The Willet FFQ was administered and food consumptions of three random days (two weekdays and one weekend day) were collected. SETTING: Cuban Americans residing in Miami. PARTICIPANTS: Twenty adult Cuban American volunteers who participated in a larger epidemiological study to evaluate the dietary risk of type 2 diabetes and cardiovascular disease. RESULTS: There were no significant differences in the mean intakes of energy, macronutrients, cholesterol and alcohol estimated by the Willett FFQ and the 3-day food records. For most of the macronutrients the correlation coefficients ranged from 0.14 to 0.71. The correlation coefficient was highest for polyunsaturated fatty acid (r = 0.71, P<0.001) and lowest for protein (r = 0.14, P=0.56). Correlation coefficients for carbohydrate (r = 0.42) and monounsaturated fatty acid (r = 0.43) were only marginally significant (P=0.06). CONCLUSION: Compared with 3-day food records, the Willett FFQ is a reasonable instrument to assess the intakes of most macronutrients and alcohol among Cuban Americans. Further studies should be conducted to validate the usefulness of the Willett FFQ in Cuban Americans for other nutrients.     

Development of a semiquantitative food frequency questionnaire to assess food, energy and nutrient intake in Denmark.

Foods to be included in a Danish self-administered semiquantitative food frequency questionnaire were identified from food tables developed, together with data collected, for the survey 'Dietary habits in Denmark, 1985'. The questionnaire was to be used in a prospective study on diet, cancer and health, and the aim was to rank individuals with regard to intake of 19 different nutrients considered of prime importance in human carcinogenesis. The questionnaire for the dietary survey included 247 foods and recipes. From stepwise multiple regression analyses with the intake of each of the 19 nutrients as the dependent variable and the intake of the 247 foods and recipes as independent variables, the foods in the models explaining 90% of the between-person variability were considered for the final questionnaire. All relevant analyses were performed for the study group as a whole, for men and women separately, and in each gender for subgroups of energy intake. Taken together, the models explaining 90% of the between-person variability identified a total of 74 foods or recipes, which were important predictors of the intake of one or more of the nutrients considered. A few foods were excluded and a few foods were added to the final questionnaire based on common biological background information, and on information on foods providing important amounts of given nutrients, but which failed to contribute to regression analyses. The 92 foods and recipes, which were included in the final questionnaire provided altogether 81% of the average total supply of the nutrients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Validation of an Australian electronic food frequency questionnaire to measure polyunsaturated fatty acid intake

Objective

To develop and validate a simple non-invasive method that estimates the intakes of omega-3 and omega-6 polyunsaturated fatty acids (PUFA) in a healthy adult population.

Methods

A new electronic PUFA food frequency questionnaire (FFQ) was validated by comparison with a 3-d weighed food record and blood biomarkers (erythrocytes and plasma) using the method of triads model and tested for reproducibility. Healthy subjects were recruited from the local Illawarra Region, New South Wales, Australia.

Results

The PUFA FFQ adequately estimated intakes for eicosapentaenoic acid, docosahexaenoic acid, total long chain omega-3 PUFA, linoleic acid, total omega-6 PUFA, and total PUFA, which were comparable with results from the 3-d food record. Eicosapentaenoic acid, docosahexaenoic acid, and total long chain omega-3 showed high validity coefficients for erythrocytes (and plasma) 0.92 (0.87), 0.69 (0.64), and 0.78 (0.73) (P < 0.05), respectively. Spearman’s rank correlation coefficients ranged from 0.48 to 0.76 when the PUFA FFQ was tested for reproducibility (P < 0.05).

Conclusion

The electronic PUFA questionnaire was found to be reproducible and is a valid tool to assess PUFA intakes in a healthy adult population.     

Validation of a food frequency questionnaire to assess intake of n-3 polyunsaturated fatty acids in subjects with and without major depressive disorder

The role of n-3 polyunsaturated fatty acids (PUFAs) in psychiatric illness is a topic of public health importance. This report describes development and biomarker validation of a 21-item, self-report food frequency questionnaire (FFQ) intended for use in psychiatric research to assess intake of α-linolenic acid (18:3n-3 [ALA]), docosahexaenoic acid (22:6n-3 [DHA]), and eicosapentaenoic acid (20:5n-3 [EPA]). In a cross-sectional study conducted from September 2006 to September 2008, sixty-one ethnically diverse adult participants with (n=34) and without (n=27) major depressive disorder completed this n-3 PUFA FFQ and provided a plasma sample. Plasma levels of n-3 PUFAs EPA and DHA, and n-6 PUFA arachidonic acid (20:4n-6 [AA]) were quantified by gas chromatography. Using Spearman's ρ, FFQ-estimated intake correlated with plasma levels of DHA (r=0.50; P<0.0001) and EPA (r=0.38; P=0.002), but not with ALA levels (r=0.22; P=0.086). Participants were classified into quartiles by FFQ-estimated intake and plasma PUFA concentrations. Efficacy of the FFQ to rank individuals into same or adjacent plasma quartiles was 83% for DHA, 78.1% for EPA, and 70.6% for ALA; misclassification into extreme quartiles was 4.9% for DHA, 6.5% for EPA, and 8.2% for ALA. FFQ-estimated EPA intake and plasma EPA were superior to plasma AA levels as predictors of the plasma AA to EPA ratio. This brief FFQ can provide researchers and clinicians with valuable information concerning dietary intake of DHA and EPA.     

Validation of a food frequency questionnaire for nutritional calcium intake assessment in Italian women

OBJECTIVE: To evaluate a food frequency questionnaire assessing calcium intake in women. DESIGN:: Estimates of calcium intake from the food frequency questionnaire were compared with those from 14 day records from 206 Caucasian women aged 25-75 y in Siena, Italy. SUBJECTS: Subjects were randomly recruited from the residents list of the city of Siena, Italy. Of the 250 initially recruited, 39 did not meet the inclusion criteria or failed to complete the diet record and five outliers were excluded before the statistical analysis on the basis that their diet record was unlikely to represent habitual intake. RESULTS: Mean dietary calcium intakes were 829+/-255 (s.d.) mg/day from the questionnaire and 818+/-260 (s.d.) mg/day from the diet record. The mean difference in intake by the two methods (-11.3+/-116.4 mg/day) did not differ significantly from zero. Specificity in classifying women consuming less than 800 mg/day calcium was 86.6%, and sensibility in classifying women consuming more than 800 mg/day calcium was 89.4%. CONCLUSIONS: The food frequency questionnaire could be used in epidemiological studies to assess calcium intake in young to elderly women. The specificity in identifying low calcium intake subjects makes it useful also as an educational tool in diet counselling and for prescribing calcium supplementation.     

Development and validation of food frequency questionnaire to assess calcium intake in postmenopausal Vietnamese women

This study was done to develop a Food Frequency Questionnaire (FFQ) for assessing calcium intake in Vietnamese based on data from the National Nutrition Survey in 2000. From the data, a total of 36 calcium-rich food items were selected for the FFQ by ranking food items according to their contribution to the population intake of nutrients. The FFQ was validated in 140 postmenopausal women by comparing estimates of calcium intake from the FFQ with those from multi-pass 24 h recalls. The results showed that the Pearson correlation coefficient between the 2 methods was 0.84 (p<0.001), and that the weighted kappa value was 0.44. Cross-classification analysis indicated that 82.1% of subjects were classified into the same or adjacent quartile by both methods. No subject was grossly misclassified by the FFQ. There is no significant difference of calcium intake between the 2 methods (by paired t test, p>0.05). A reproducibility study also presented good correlation between 2 administrations of the FFQ, with Pearson correlation coefficient being 0.93 (p<0.001) and weighted kappa value being 0.67. In conclusion, this FFQ is useful and reliable for estimating calcium intake in population-based epidemiological studies in postmenopausal Vietnamese women.     

Calibration of the food list and portion sizes of a food frequency questionnaire applied to free-living elderly people

ObjectiveTo calibrate the food list and relative portion sizes of a food frequency questionnaire (FFQ) for application to a free-living, healthy, elderly population.MethodsCross-sectional study. One hundred free-living, healthy participants, aged from 60 to 75 y, randomly selected from among individuals in the area served by the Family Health Program, School of Medicine of Ribeirao Preto, University of São Paulo. A Food Frequency Questionnaire (FFQ) and a Diet History Questionnaire (DH) were applied by trained dietitians. Each food item of the FFQ had its portion size recalculated according to the percentiles referenced by the volunteers in the DH (25th = small, 50th = medium, and 75th = large). The list of foods and portion sizes of the original FFQ and those obtained by the application of the DH were compared. The percent contribution of energy, protein, fat, carbohydrate, folic acid, vitamin C, calcium, and fiber of each food item mentioned in the FFQ was determined from the data obtained by the application of the DH.ResultsFFQ, as compared with the DH, provided good estimation of the intake of protein, calcium, folic acid, and fiber (paired t test P < 0.05). Portion sizes of the FFQ differed from those obtained by the application of the DH (?23% to 300%).ConclusionsAdjustments to the FFQ in particular, new portion sizes and a reduction of the food list were found to be appropriate for application to healthy, urban, free-living elderly people in Ribeirao Preto, Brazil.