Relative validity of a food frequency questionnaire among tin miners in China: 1992/93 and 1995/96 diet validation studies

Reproducibility and Validity of a Food Frequency Questionnaire for Assessing Dietary Consumption via the Dietary Pattern Method in a Chinese Rural Population

Objective

This study was conducted to assess the reproducibility and validity of a food frequency questionnaire (FFQ) that was developed to assess the overall dietary consumption via dietary pattern method in a rural population in southwest China.

Methods

A total of 179 participants aged between 40 and 70 years old were included in this study. Participants administered FFQ at baseline (FFQ1) and one year later (FFQ2) to assess the reproducibility. Six 3-day 24-hour recalls (24HRs) were completed between the administrations of two FFQs to determine the validity. Dietary patterns from three separate dietary sources were derived by using principle component factor analysis. Comparisons between dietary pattern scores were made by using Pearson or intraclass correlation coefficient, cross-classification analysis, weighted kappa (κ) statistic and Bland-Altman analysis. The de-attenuated method was adopted to correct the monthly and seasonally variation and the partial correlation analysis was used correct the influence by total energy intake.

Results

Two major dietary factors, labeled as prudent pattern and processed food pattern, were identified. The prudent pattern was characterized by higher factor loadings of wheat, rice, fresh vegetables, bean products, nuts, red meat, white meat and fresh eggs; and the processed food pattern was characterized by higher factor loadings of pickled vegetables, preserved vegetables and salted meat. Between Two FFQs, intraclass correlation coefficients were 0.57 for prudent pattern and 0.55 for processed food pattern, partial Pearson correlation coefficients were 0.51 for the prudent pattern and 0.56 for the processed food pattern; weighted κ statistic ranged from 0.45 (for the prudent pattern) to 0.56 (for the processed food pattern). Between FFQs and 24HRs, de-attenuated correlation coefficients ranged from 0.54 to 0.78 for the prudent pattern and from 0.55 to 0.61 for the processed food pattern; partial Pearson correlation coefficients ranged from 0.41 to 0.56 for the prudent pattern and from 0.42 to 0.44 for the processed food pattern; weighted κ statistic ranged from 0.42 to 0.46 for prudent pattern and from 0.43 to 0.60 for processed food pattern. The Bland-Altman plots and limits of agreement indicated that the deviation/divergence was not obvious for both of the patterns between FFQ1 and FFQ2 and between FFQs and 24HRs.

Conclusion

The study suggests that the FFQ is reasonably reproducible and valid to assess the overall dietary consumption via dietary pattern methods in the Chinese rural population.

Food-frequency questionnaires: a review of their design, validation and utilisation

A review of the literature concerning the design, utilisation and validation of food-frequency questionnaires (FFQ) has been carried out using a semi-systematic approach to obtaining, reviewing and extracting data from articles. Databases were searched from 1980 to 1999. The present review identified 227 validation (from 1980 to September 1999) and 164 utilisation (for 1998 only) studies. A number of design issues have been evaluated through the present review. These include: the need to consider how portion sizes have been described, self-defined giving higher mean correlations; how an FFQ was administered, interviewer-administered giving higher mean correlations for some nutrients; how many items to include on an FFQ, those with the largest number of items having higher correlations. Validation techniques were described. Most validation studies involved comparing an FFQ against another dietary assessment method; only 19 % compared an FFQ to a biomarker. Measurement differences were most commonly assessed by correlation coefficients as opposed to other more appropriate methods. Mean correlation coefficients were highest for Ca and fat, and lowest for vitamin A and vegetables. The utilisation studies showed that FFQ were most commonly used in cross-sectional surveys, with ninety-three of the FFQ being designed to be disease-specific. The present review results were presented to a group of experts and a consensus arrived at concerning the development, validation and use of FFQ. Recommendations derived from the consensus arising from the literature review are presented as an appendix to the present paper.

Assessing the intake of obesity-related foods and beverages in young children: comparison of a simple population survey with 24 hr-recall

Background

With an increasing focus on obesity prevention there is a need for simple, valid tools to assess dietary indicators that may be the targets of intervention programs. The objective of this study was to determine the relative validity of previous day dietary intake using a newly developed parent-proxy questionnaire (EPAQ) for two to five year old children.

Methods

A convenience sample of participants (n = 90) recruited through preschools and the community in Geelong, Australia provided dietary data for their child via EPAQ and interviewer-administered 24-hour dietary recall (24 hr-recall). Comparison of mean food and beverage group servings between the EPAQ and 24 hr-recall was conducted and Spearman rank correlations were computed to examine the association between the two methods.

Results

Mean servings of food/beverage groups were comparable between methods for all groups except water, and significant correlations were found between the servings of food and beverages using the EPAQ and 24-hr recall methods (ranging from 0.57 to 0.88).

Conclusion

The EPAQ is a simple and useful population-level tool for estimating the intake of obesity-related foods and beverages in children aged two to five years. When compared with 24-hour recall data, the EPAQ produced an acceptable level of relative validity and this short survey has application for population monitoring and the evaluation of population-based obesity prevention interventions for young children.

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

BACKGROUND AND OBJECTIVE

The validity of food frequency questionnaires (FFQs) in measuring food consumption and nutrient intake has to be assessed. The objective of this study was to assess the validity of a 128-item FFQ in specific subgroups of Finnish adults.

METHODS

The study included 294 subjects (137 men and 157 women). A 3-day food record was used as the reference method.

RESULTS

The mean intake of all nutrients except alcohol was higher measured with the FFQ than with the food records. In general, the Pearson correlations for energy adjusted nutrients between the FFQ and the food records were higher in women than in men. The correlations ranged from 0.14 (retinol) to 0.66 (fiber and alcohol) in men, and from 0.20 (long-chain n-3 fatty acids) to 0.70 (alcohol) in women. The results in subgroups showed that measuring nutrient intakes is more difficult among younger (30-50 years) women and overweight men and women than among others.

CONCLUSIONS

The study showed that the FFQ is a useful tool in epidemiologic studies in measuring the diet of Finnish adults given that the problems among specific subgroups are taken into account in interpretation.

Relative validity of food intake estimates using a food frequency questionnaire is associated with sex, age, and other personal characteristics

We investigated the validity of food intake estimates obtained by a self-administered FFQ relative to weighed food records (WFR) and the extent to which demographic, anthropometric, and social characteristics explain differences between these methods. A community-based sample of 96 Australian adults completed a FFQ and 12 d of WFR over 12 mo. The FFQ was adapted to the Australian setting from the questionnaire used in the US Nurses' Health Study. Spearman rank correlation coefficients ranged from 0.08 for "other vegetables" to 0.88 for tea. Exact agreement by quartiles of intake ranged from 27% (eggs) to 63% (tea). Differences between FFQ and WFR regressed on personal characteristics were significantly associated with at least 1 characteristic for 20 of the 37 foods. Sex was significantly associated with differences for 17 food groups, including 5 specific vegetable groups and 2 "total" fruit and vegetable groups. Use of dietary supplements and the presence of a medical condition were associated with differences for 5 foods; age, school leaving age, and occupation were associated with differences for 1-3 foods. BMI was not associated with differences for any foods. Regression models explained from 3% (whole-meal bread) to 37% (for all cereals and products) of variation in differences between methods. We conclude that the relative validity of intake estimates obtained by FFQ is different for men and women for a large number of foods. These results highlight the need for appropriate adjustment of diet-disease relations for factors affecting the validity of food intake estimates.

The National Cancer Institute diet history questionnaire: validation of pyramid food servings

The performance of the National Cancer Institute's food frequency questionnaire, the Diet History Questionnaire (DHQ), in estimating servings of 30 US Department of Agriculture Food Guide Pyramid food groups was evaluated in the Eating at America's Table Study (1997-1998), a nationally representative sample of men and women aged 20-79 years. Participants who completed four nonconsecutive, telephone-administered 24-hour dietary recalls (n = 1,301) were mailed a DHQ; 965 respondents completed both the 24-hour dietary recalls and the DHQ. The US Department of Agriculture's Pyramid Servings Database was used to estimate intakes of pyramid servings for both diet assessment tools. The correlation (rho) between DHQ-reported intake and true intake and the attenuation factor (lambda) were estimated using a measurement error model with repeat 24-hour dietary recalls as the reference instrument. Correlations for energy-adjusted pyramid servings of foods ranged from 0.43 (other starchy vegetables) to 0.84 (milk) among women and from 0.42 (eggs) to 0.80 (total dairy food) among men. The mean rho and lambda after energy adjustment were 0.62 and 0.60 for women and 0.63 and 0.66 for men, respectively. This food frequency questionnaire validation study of foods measured in pyramid servings allowed for a measure of food intake consistent with national dietary guidance.

A quantitative food frequency questionnaire for women in southeast China: development and reproducibility

This study describes the development and reproducibility of a 128-item quantitative food frequency questionnaire (FFQ) to measure usual food consumption for women in southeast China. The FFQ was pre-tested using 51 Chinese women who recently migrated to Australia. Cronbach's alpha coefficient was 0.81 for internal consistency. The reliability of the FFQ was then assessed by another test-retest study. A sample of 41 women residing in southeast China was interviewed twice within 12 weeks. Intraclass correlation coefficients were moderate to high for mean food group consumption (0.43-0.96) and mean daily nutrient intakes (0.47-0.89). Kappa statistics for eating habits ranged from 0.27 to 0.89 in the test-retest. The mean ratio of energy intake to basal metabolic rate was 1.73 (S.D. 0.39) in both test and retest samples. The study confirmed that the FFQ method using standard containers is appropriate to assess dietary intake for women in southeast China.

Relative Validity and Reliability of a Food Frequency Questionnaire for a Triethnic Population of 1-Year-Old to 3-Year-Old Children from Low-Income Families

OBJECTIVE

To develop and validate a food frequency questionnaire (FFQ) for low-income, 1- to 3-year-old Hispanic, African-American, and white children.

DESIGN

A convenience sample of low-income mothers provided dietary data for their child via FFQs and 3-day diet records.

SUBJECTS/SETTING

Participants (N=77) were recruited from Special Supplemental Program for Women, Infants, and Children clinics and public health clinics. All subjects were Hispanic, African-American, or white mothers of children 1 to 3 years old, 18 years of age or older, income less than 200% of the federal poverty level, and were literate in English. Statistical analyses performed Wilcoxon signed-ranks tests were used for comparisons of food group servings on time 1 and time 2 FFQs and to examine differences in food group servings between the FFQ and diet records. Spearman correlations were calculated to assess test-retest reliability and the relative validity. Contingency tables were used to determine the degree of association between the FFQ and diet records.

RESULTS

Reliability correlations were significant for all nine food categories ( =0.69), ranging from 0.53 (soups) to 0.84 (nonstarchy vegetables). Validity correlations were significant for all food groups ( =0.41) except starchy vegetables. Thirty-six percent of children were classified into the same quartile of food group intake and 78% into the same or within one quartile.

CONCLUSIONS

The FFQ yielded excellent reliability and acceptable validity and can be used to assess food choices in a triethnic sample of low-income 1- to 3-year-old children.

Validation of a semi-quantitative food-frequency questionnaire for use among adults in Guatemala

OBJECTIVE

The purpose of the study was to assess the validity of a 52-item semi-quantitative food-frequency questionnaire (FFQ) by comparing it with multiple 24-hour dietary recalls.

DESIGN

Three non-consecutive 24-hour dietary recalls and one FFQ were administered over a one-month period.

SETTING

Four communities of El Progreso, Guatemala.

SUBJECTS

Seventy-three individuals aged 22-55 years.

RESULTS

: Intakes of energy and other nutrients as measured by the FFQ were higher than intakes measured by 24-hour recalls. Energy was overestimated by 361 kcal, and nutrient overestimates were particularly great for vitamin C and iron. Pearson correlation coefficients for crude energy and nutrients intakes ranged from 0.64 for energy to 0.12 for vitamin C. Exact agreement for both methods (measured by the concordance correlation coefficient) ranged from 0.59 (fat) to 0.06 (vitamin C). Pearson correlation coefficients for energy-adjusted nutrients ranged from 0.59 (carbohydrates) to 0.11 (thiamin). Pearson correlation coefficients for the proportion of total energy derived from specific foods ranged from 0.59 (tortillas) to 0.01 (sugared beverages). Cross-classification of quartiles of crude nutrient intakes for both methods indicated that <11% were grossly misclassified; after adjusting for energy intake, <13% were grossly misclassified.

CONCLUSIONS

This FFQ provides good measures of energy and macronutrient intakes and a reasonably reliable measure of micronutrient intake, indicating its suitability for comparing exposures within a study population in reference to heath-related endpoints. Our results highlight the need to adapt any FFQ to specific cultural needs - in this case, the Guatemalan 'core foods' (tortilla, bread and beans), for which inter-individual variability in intake is high.