Validity and Reproducibility of a Food Frequency Questionnaire for Dietary Assessment in Japanese People.

A 76-item food frequency questionnaire (FFQ) was developed to investigate nutritional epidemiology in urban residents in Japan. The authors prepared two food models-a life-size three-dimensional model and a life-size two-dimensional photograph-to assess the FFQ portion size. The validity of the FFQ was verified using the two food models by comparing them with 16-d weighted dietary records (WDRs). Validation was conducted by comparing the FFQ1 findings with those obtained with the WDR, which is regarded as the gold standard, and reproducibility was verified by comparing the findings from FFQ2 and FFQ1. After completion of the WDR, the participants were randomized into two groups. In one group, the FFQ was conducted using life-size three-dimensional models (3D-FFQ) to estimate the portion size. In the other group, the FFQ was administered using life-size photo collection (2D-FFQ). Regarding validity, the median values (range) of Pearson's correlation coefficients for the energy and nutrient intake of the 32 items by the WDR and FFQ1 were r=0.53 (0.30-0.68) in the 3D-FFQ and r=0.57 (0.33-0.87) in the 2D-FFQ. When FFQs with 2D or 3D food models and two different portion sizes were compared with regard to the intake of certain food groups, energy, and nutrients, both the 2D-FFQ and 3D-FFQ provided good correlation coefficients with the WDR.

Effectiveness of diet versus exercise intervention on weight reduction in local Japanese residents.

OBJECTIVE: To evaluate the effect of diet versus exercise intervention on weight reduction. METHODS: Participants were randomly divided by gender, age, and living area into four groups: group DE (diet and exercise, n = 16), group D (diet only, n = 15), group E (exercise only, n = 15), and group C (control, n = 16). This study ultimately aimed to help participants reduce their body mass index (BMI) by 7% of baseline value. Subjects were 62 residents (men and women ranging in age from 40 to 69 years) of two residential areas in Nara Prefecture, Japan, who participated in annual health checkups in 2006. BMI of the participants was ≥24 and <28 kg/m² at baseline examination. All participants agreed to undergo a 6-month intervention between January 2007 and September 2007. RESULTS: In our intention-to-treat analysis, mean change in BMI from baseline to final examination was as follows: group DE mean BMI decreased 6.6%, group D mean BMI decreased 5.3%, group E mean BMI decreased 2.3%, and group C mean BMI decreased 2.2%. The reduction in BMI from baseline to final examination was significant in all groups (DE, p < 0.001; D, p < 0.001; E, p = 0.009; C, p = 0.019). Further, mean abdominal circumference was significantly reduced in all groups. Blood glucose levels were significantly reduced only in group DE (p = 0.047). CONCLUSION: Combined intervention with diet and exercise proved to be effective in weight reduction, whereas exercise intervention alone was not found to be effective.

Reproducibility and validity of the food frequency questionnaire for estimating habitual dietary intake in children and adolescents.

BACKGROUND: A previous study reported the development a 75-item food frequency questionnaire for Japanese children (CFFQ). The first aim was to examine the reproducibility and validity of the CFFQ in order to assess dietary intake among two groups; 3-11 year old children (YC group) and 12-16 year old children (AD group). The second aim was to use the CFFQ and the FFQ for adults (AFFQ), and to determine which was better suited for assessing the intake of children in each group. METHODS: A total of the 103 children participated in this study. The interval between the first CFFQ and AFFQ and the second CFFQ and AFFQ was one month. Four weighted dietary records (WDRs) were conducted once a week. Pearson's correlation coefficients between the first and second FFQs were calculated to test the reproducibility of each FFQ. Pearson's correlation coefficients between WDRs and the second FFQ were calculated for the unadjusted value and sex-, age-, and energy-adjusted values to determine the validity of each FFQ. RESULTS: The final number of subjects participating in the analysis was 89. The median correlation coefficients between the first and second CFFQs and AFFQs were 0.76 and 0.73, respectively. There was some over/underestimation of nutrients in the CFFQ of the YC group and in the AFFQ of the AD group. The medians of the sex-, age-, and energy-adjusted correlation coefficients were not different between the YC and AD groups for each FFQ. The correlation coefficient in sex-, age-, and energy-adjusted value revealed that the largest number of subject with high (0.50 or more) value was obtained by the CFFQ in the YC group. CONCLUSIONS: This study indicated that the CFFQ might be a useful tool for assessing habitual dietary intake of children in the YC group. Although the CFFQ agreed moderately with habitual intake, it was found to underestimate intake in theAD group. However, for the AFFQ, the ability to rank habitual intake was low. Therefore, it is necessary to develop a new FFQ or modify an existing FFQ to accurately assess the habitual diet of children in the AD group.

Development of a food frequency questionnaire to estimate habitual dietary intake in Japanese children.

BACKGROUND: Food frequency questionnaires (FFQ) are used for epidemiological studies. Because of the wide variations in dietary habits within different populations, a FFQ must be developed to suit the specific group. To date, no FFQ has been developed for Japanese children. In this study, we developed a FFQ to assess the regular dietary intake of Japanese children. The FFQ included questions regarding both individual food items and mixed dishes. METHODS: Children (3-11 years of age, n = 621) were recruited as subjects. Their parents or guardians completed a weighed dietary record (WDR) for each subject in one day. We defined FOOD to be not only as a single food item but also as a mixed dish. The dieticians conceptually grouped similar FOODs as FOOD types. We used a contribution analysis and a multiple regression analysis to select FOOD types. RESULTS: We obtained a total of 586 children's dietary data (297 boys and 289 girls). In addition, we obtained 1,043 FOODs. Dieticians grouped into similar FOODs, yielding 275 FOOD types. A total of 115 FOOD types were chosen using a contribution analysis and a multiple regression analysis, then we excluded overlapping items. FOOD types that were eaten by fewer than 15 subjects were excluded; 74 FOOD types remained. We also added liver-based dishes that provided a high amount of retinol. A total of 75 FOOD types were finally determined for the FFQ. The frequency response formats were classified into four type categories: seven, eight, nine and eleven, according to the general intake frequency of each FOOD type. Information on portion size was obtained from the photographs of each listed FOOD type in real scale size, which was the average amount of the children's portion sizes. CONCLUSIONS: Using both a contribution analysis and a multiple regression analysis, we developed a 75-food item questionnaire from the study involving 586 children. The next step will involve the verification of FFQ reproducibility and validity.

[The impact of sedentary lifestyle on risk factors for cardiovascular disease among Japanese young women].

OBJECTIVE: The purpose of this study was to examine body composition, blood biochemical markers, and dietary intake in 2 groups of young women engaged in different physical activities and to assess the impact of sedentary lifestyle on risk factors for diabetes and cardiovascular disease. METHODS: The subjects were 208 students of a women's university. Of these, 108 majored in nutrition (physically sedentary group, SG) and 100 majored in sports (physically active group, AG). We conducted a survey from mid-June to mid-July in 2004, during which physical examinations, including measurements of body weight and height, evaluation of body composition using dual energy X-ray absorptiometry (DXA), determination of the ankle brachial index (ABI) by measuring the brachial and ankle systolic and assessment of diastolic blood pressure, blood biochemical tests, and examination of 7-day weighted diet records (DRs) were all conducted. The physical and blood biochemical values and the food and nutrient intakes calculated from the DRs were then compared between the groups. RESULTS: We analyzed a total 133 subjects who had completed all the DRs (78 SG subjects and 55 AG subjects). A comparison between the 2 groups revealed mean body mass indices (BMIs) of 20.5 and 21.4 kg/m2 and mean body fat percentages of 29.4% and 22.6% in the SG and AG subjects, respectively. Even though the SG subjects had lower BMIs, they had significantly higher body fat percentages. The ankle systolic blood pressure and ABI were significantly higher in the AG subjects. With regard to blood biochemistry, the HOMA-beta, leptin, and apoprotein-B levels were significantly higher in the SG subjects. The mean energy intakes (kcal/day) of the SG and AG subjects was 1550 and 1853, respectively. The intakes of most nutrients were significantly higher in the AG subjects, and the amount of food consumed by the SG subjects was low. CONCLUSION: The levels of blood biochemical markers such as leptin and apoprotein-B were higher and the ABI was lower in the SG subjects than in the AG subjects. We think that these results are attributable to the accumulation of body fat, including visceral fat. Therefore, it is important for SG subjects to increase their energy expenditure by regular exercise and consume a diet that corresponds to their dietary requirements.

Reduction in estimated vitamin A intake induced by new food composition tables in Japan, where vitamin A is taken mostly from plant foods.

A revised edition of the standard tables of food composition was implemented in Japan in 2005; one of the major revision points is the change of retinol activity equivalents for pro-vitamin A carotenoids. This preliminary analysis was conducted to examine whether the revision affects the estimation of vitamin A intake; and if so, to what extent. Accordingly, a field survey was conducted to collect 24-h duplicates of daily foods of citizens, and 26 adult women volunteered. Application of the procedures in the new and previous standard tables of food composition gave 537 microg retinol activity equivalent and 704 microg retinol equivalence, respectively, for daily vitamin A intake. Thus, the changes in retinol activity equivalents induced substantial reduction (by 24%) in estimation of vitamin A intake among the Japanese population, for whom pro-vitamin A carotenoids in plant foods are the major sources (76%) for vitamin A, and retinol accounts for only 35% (on the retinol activity equivalent basis).

Limited acceptance of globalization in food habits among middle-aged women in Osaka, Japan.

The study was initiated to identify the effects of recent changes in dietary pattern in Japan on nutrient intake. In the large city of Osaka, Japan, 24-h food duplicate samples were collected from 26 middle-aged women, and nutrients in the duplicates were estimated in reference to standard tables of food composition. The subjects took 1844 kcal (7.72 MJ) energy, 67.5 g protein, and 54.5 g lipid (37% from plants) per day. Micro-nutrient intakes were generally sufficient, but NaCl intake tended to be excessive, and the relatively high body mass index (>25 in six cases) suggested a possibility of over-eating. The food composition was rich in rice and fish, being basically of a traditional type. Consumption of bread, an acquired habit, was observed in 65% of the breakfasts but less so in lunch and none in dinner. Thus, the acceptance of bread in place of rice was limited and did not induce substantial alteration in nutrient intakes.