Analysing food groups and nutrient intake in adults who met and did not meet the daily recommended vegetable intake of 350 g: the 2016 National Health and Nutrition Survey in Japan.

This study aimed to compare the differences in the intake of food groups and nutrients between Japanese adults who consumed the recommended daily vegetable intake (350 g/day) and those who did not. Dietary information was obtained from one-day dietary records collected from the 2016 National Health and Nutrition Survey, which was conducted in 46 prefectures in Japan. The participants aged ≥20 years (n = 21,606; 53.8% women) were classified into the < and ≥350 g/day groups. Inter-group differences for 17 food groups and 27 nutrients were assessed as percentages of consumers (food groups only) and energy-adjusted intake (units/MJ/d or % of total energy intake). Overall, 29% of participants consumed ≥350 g/day of vegetables. The ≥350 g/day group had a higher percentage of consumers and energy-adjusted intakes for all vegetable subgroups than the <350 g/day group. For other food groups, the ≥350 g/day group had higher percentages of consumers for all food groups, except for cereals, eggs, and condiments and seasonings, which showed no significant differences. However, the ≥350 g/day group had a significantly higher energy-adjusted intake for potatoes and other tubers, mushrooms, meats, and condiments and seasonings but a significantly lower value for cereals, eggs, savoury snacks and confectionaries, and beverages. The ≥350 g/day group had a significantly higher intake of almost all (25/27) nutrients, including sodium, than the <350 g/day group. Participants with vegetable intake ≥350 g/day might have a more favourable intake of food groups and nutrients; however, watching for salt intake is necessary when promoting vegetable intake.

Are higher protein intake and distribution of protein intake related to higher appendicular muscle mass among an older Japanese population?: A cross-sectional analysis of the National Health and Nutrition Survey 2017.

AIM: Protein intake is an important component in retaining muscle mass, especially among older people. This study examined the relationship between total protein intake and/or the distribution of protein intake in each meal and appendicular muscle mass, using data from the National Health and Nutrition Survey (NHNS) in Japan. METHODS: Data from the NHNS were re-analyzed in this study. We used data from a one-day dietary record, physical examination, and lifestyle questionnaire completed by 1766 participants aged over 60 years. Appendicular muscle mass was assessed by multiple-frequency bioimpedance measurement. Leucine intake was calculated by the weighted average amino acid content from all 98 food subcategories used in the NHNS, based on amino acid composition data in the 2020 Standard Tables of Food Composition. RESULTS: Participants with higher protein intake showed significantly higher appendicular muscle mass. This relationship was independent of physical activity, including steps taken per day, exercise habit, and physical labor. Frequent intake of ≥0.4 g protein/kg/meal was not related to appendicular muscle mass. The combination of higher total protein intake and higher physical activity seemed to have the largest association with appendicular muscle mass. CONCLUSIONS: Higher protein intake may be related to higher appendicular muscle mass, independent of higher physical activity, among older Japanese people. Geriatr Gerontol Int 2024; ••: ••-••.

Trend of estimated participation rate by regional block, gender, and age group in the 1997-2019: National Health and Nutrition Survey in Japan.

This study aimed to identify the trend of approximate participation rate in Japan's National Health and Nutrition Survey (NHNS_J). The proportion of participants among all residents of surveyed districts (estimated participation rate: EPR) was calculated by 12 regional blocks, gender, and age group, and the trend and annual percent change (APC) were clarified. Based on the 1997-2019 NHNS_J data, we created a database classified by prefecture, gender, and age group; in addition to these, the number of people per household by Population Census or population estimates were obtained from e-Stat and added to the database. All analyses were performed by regional block and gender and EPR for each year was calculated by the age group. Trends of EPR, overall and by the age group, were presented using graphs, illustrating the exponential regression curve. The graphs showed APC, standard error, and statistical significance by age group. The EPRs were declining in all the regional blocks. Additionally, the rates of decline in APC in young people under the age of 50 years were higher than those in the older age groups in 9 of 12 regional blocks. The nationwide APC in the age group <50 years was significantly larger than that in the age group ≥50 years. The declining EPR trend in NHNS_J in all regional blocks (especially among younger people) suggests the need for a strategy to improve participation rates in the future.

A scoping review of dietary assessment questionnaires potentially suitable for assessing habitual dietary intake in the National Health and Nutrition Survey, Japan.

This scoping review aimed to identify questionnaire-based dietary assessment methods for use in the National Health and Nutrition Survey (NHNS) in Japan. The search was conducted in three databases (PubMed, Web of Science, and Ichushi) to identify questionnaire such as food frequency questionnaire and dietary history questionnaire validated against dietary recalls or food records for the intakes of both food groups and nutrients among Japanese adults. Study quality was assessed based on previously developed criteria. We extracted the questionnaire characteristics and the design and results of the validation studies. We identified 11 questionnaires, with the number of food items ranging from 40 to 196, from 32 articles of good quality. In the validation studies, participants were aged 30-76 years and 90% of the articles used ≥3 d dietary records as reference. The number of nutrients and food groups with a group-level intake difference within 20% against the reference method ranged from 1 to 30 and 1 to 11, respectively. The range of mean correlation coefficients between questionnaire and reference methods were 0.35-0.57 for nutrients and 0.28-0.52 for food groups. When selecting a survey instrument in the NHNS from the 11 existing questionnaires identified in this study, it is important to select one with high group-level comparison and correlation coefficient values on the intended assessment items after scrutinizing the design and results of the validation study. This review may serve as a reference for future studies that explore dietary assessment tools used for assessing dietary intake in specific representative populations.

[Corrigendum: How accurate are self-reported anthropometrics among the Japanese? A scoping review].

　Nihon Koshu Eisei Zasshi(JAPANESE JOURNAL OF PUBLIC HEALTH), Vol. 70 (2023) No. 12 pp.817-827.

Factors associated with physical growth status among children aged 12-59 months in the Japanese National Growth Survey on Preschool Children: A retrospective analysis.

This study aimed to examine the factors associated with physical growth status among children aged 12-59 months in Japan. Data from the 2010 National Growth Survey on Preschool Children, a nationwide cross-sectional survey, were used for this analysis (n = 4196). After adjustment for confounding factors, multiple logistic regression analyses showed that boys who were born small-for-gestational-age were more likely to be underweight (adjusted odds ratio [aOR]: 12.55, 95% confidence interval [CI]: [6.76-23.3], p < 0.001), stunted (aOR: 5.78, 95% CI: [3.48-9.60], p < 0.001) and wasted (aOR: 7.02, 95% CI: [3.30-15.0], p < 0.001), while boys who were large-for-gestational-age were less likely to be stunted (aOR: 0.26, 95% CI: [0.11-0.60], p < 0.01). Girls who were born small-for-gestational-age were more likely to be underweight (aOR: 5.42, 95% CI: [2.73-10.7], p < 0.001), stunted (aOR: 4.04, 95% CI: [2.43-6.73], p < 0.001) and wasted (aOR: 6.27, 95% CI: [2.55-15.4], p < 0.001), while girls who were large-for-gestational age were more likely to be overweight (aOR: 5.90, 95% CI: [1.64-21.3], p < 0.001). Moreover, the following factors were associated with the physical growth status in children: maternal prepregnancy body mass index, complications during pregnancy, continuous breastfeeding, initiation age of complementary feeding, smoking status of the father or those living with the mother during pregnancy and birth order. Further research is needed to expand support for high-risk families and to verify their effectiveness.

Time Trends in Income-related Differences in Food Group Intakes: The National Health and Nutrition Survey, Japan in 2010, 2014, and 2018.

BACKGROUND: We aimed to clarify whether differences in food group intake according to household income have changed over the last decade in Japanese people aged 20 years or older. METHODS: This cross-sectional study was based on the 2010, 2014, and 2018 National Health and Nutrition Surveys in Japan. Food intake was assessed using a 1-day semi-weighed household dietary record. The participants were categorized into three groups based on their income. The mean of each food intake according to the income group was estimated by adjusting for age, occupation, and number of participants from the same household. The significance of the interaction terms between income and survey year was evaluated to assess the change in income-related differences in food intake over time. RESULTS: Cereal intake was lower in the middle- and the highest-income groups than in the lowest-income group, regardless of sex, and the interaction between income and year was nonsignificant for cereal intake. In the former two surveys, vegetable intake was higher among the highest-income women, while in the 2018 survey, the vegetable intake decreased in the women in the middle- and the highest-income groups. The interaction between income and year was significant for vegetable intake among the women. For other foods, the differences in intake among the income groups did not significantly change over time. CONCLUSION: The tendency for lower cereal intake in the higher-income groups was consistent over time in both the sexes, and the tendency for higher vegetable intake in the highest income women disappeared over time.

National Nutrition Surveys Applying Dietary Records or 24-h Dietary Recalls with Questionnaires: A Scoping Review.

Development of an accurate and efficient dietary method is required for national nutrition surveys. Some countries conduct dietary surveys and combine 24-h dietary records or 24-h dietary recalls with dietary questionnaires. This scoping review aimed to summarize studies that used results from national surveys that combined detailed dietary surveys (dietary records or 24-h dietary recall) and dietary questionnaires and identify the purpose of combining the two methods. The PubMed database and manual searches were used for the literature review. We extracted 58 articles from 16 national nutrition surveys from 14 countries. Most studies used 24-h dietary recall for detailed dietary surveys and the food frequency questionnaire (FFQ) or food propensity questionnaire (FPQ) for questionnaire surveys. Among 37 studies from eight countries, the purpose of combining the two dietary survey methods was to estimate energy and nutrient intakes from detailed dietary surveys and habitual food intake from questionnaires. These findings are useful as a reference when introducing new dietary survey methods in future national nutrition surveys.

[How accurate are self-reported anthropometrics among the Japanese? A scoping review].

Objectives　Monitoring of obesity and underweight prevalence in general populations is crucial for the implementation of effective public health measures. Self-reported height and weight values are often used to assess the body mass index (BMI) in such epidemiological surveillance. However, it is known that using self-reported height and weight may underestimate the prevalence of obesity (BMI≥25 kg/m2), while its accuracy for underweight (BMI<18.5 kg/m2) prevalence is not well-understood. The aim of this study was to conduct a scoping review on the accuracy of self-reported anthropometrics in the Japanese population, where both obesity and underweight are prevalent.Methods　Using PubMed and CiNii Research, a literature search was conducted for studies published in English or Japanese by 2022 that were conducted in Japan and compared self-reported and measured height, weight, or/and BMI. The study design and mean reported errors (mean of reported values－mean of measured values) were extracted and tabulated, and differences by BMI categories were also considered.Results　A total of 17 studies, with 11 being published in English, were included in this review. These studies were conducted in nationwide cohort studies (n=4), local populations (n=4), workplaces (n=3), and educational institutions (n=6), with diverse age ranges (10-91 years) and sample sizes (<100 to >30,000). Although the degree of mean reporting error varied between studies, most of the studies reported that height was overreported, weight was underreported, and BMI was underestimated. In the three studies that reported mean reporting errors by BMI category, the direction of reporting error for height remained consistent across all body size categories, while weight and BMI were overreported and overestimated only among the underweight. Four studies in adults showed that 14.2-37.6% of actually obese individuals and 11.1-32.3% of underweight individuals were misclassified as 'normal range' (18.5≤BMI<25 kg/m2) based on self-reporting, while 0.8-5.4% and 1.2-4.1% of individuals actually within the normal range were misclassified as 'underweight' and 'obese' based on self-report, respectively.Conclusion　This study suggests that using BMI based on self-reported height and weight can underestimate the prevalence of both obesity and underweight in the Japanese population. These biases should be taken into consideration when using self-reported anthropometrics in epidemiological studies.

Trends in Mean Energy and Nutrient Intakes in Japanese Children and Adolescents: The National Health and Nutrition Survey, 1995-2019.

This study aimed to describe the national trends in mean energy and nutrient intakes in Japanese children and adolescents from 1995 to 2019. We used data obtained from the National Health and Nutrition Survey and included 54,871 participants aged 1-19 years. The dietary intake was estimated using a 1-day, semi-weighed, household-based, dietary record. The trends of mean energy and nutrient intakes were analyzed using the Joinpoint Regression Program. A declining trend in the mean energy intake was observed in toddlers aged 1-6 years, school girls aged 7-14 years, and adolescent girls aged 15-19 years, while the mean energy intake from protein, fat, and carbohydrates changed little over time. The mean salt equivalent showed a decreasing trend in all age groups, although the 2019 mean values were above the tentative dietary goal for preventing lifestyle-related diseases, especially in adolescent boys. Declining trends in mean vitamin (vitamin A, vitamin B12, folate, vitamin D, and vitamin K) and mineral (calcium, iron, and copper) intakes were observed, while trends in the mean vitamin B6 and zinc intakes were unchanged since 2001. Continuous monitoring of dietary intake and further research are required to raise awareness of unhealthy diet habits and to improve the food environment for the healthy growth and development of children and adolescents.

Nutritional Adequacy Assessment of the Japanese Diet Using the Number of Dishes Compared to Existing Dietary Diversity Indices: A Cross-Sectional Analysis from the 2012 National Health and Nutrition Survey, Japan.

The Japanese diet has attracted attention as a factor contributing to the Japanese population's longevity. A typical Japanese meal, traditionally called "ichiju-sansai," is composed of various dishes. This study assessed the nutritional adequacy of the Japanese diet using the number of dishes in all meals (NDAM) compared to existing dietary diversity indices (DDIs). This cross-sectional study used data from the 2012 National Health and Nutrition Survey. A total of 25,976 participants aged ≥20 y were included in this study. NDAM was calculated for whole dishes or single foods (except supplements and beverages) from one-day weighted dietary records. The food variety score (FVS), number of foods, dietary diversity score (DDS), and number of food groups are some of the existing DDIs. NDAM had relatively high positive correlation coefficients with potassium, magnesium, and dietary fiber. The partial correlation coefficients with an indicator of the overall nutrient adequacy of NDAM was 0.42 for men and 0.42 for women. It was almost the same as that of the FVS (men: 0.44, women: 0.42) and DDS (men: 0.44, women: 0.43). On the other hand, NDAM, similar to existing DDIs, was also positively correlated with nutrient restriction in both sexes. These findings indicate that the nutrient adequacy of NDAM is similar to that of the existing DDIs. Because of the higher sodium intake and cholesterol intake in higher NDAM and existing DDIs, the effect of higher NDAM on health outcomes must be investigated in future studies.

Current Findings from the Japan National Health and Nutrition Survey.

In this Special Issue, six articles using the Japan National Health and Nutrition Survey (NHNS) were published [...].

Validation of Dietary Intake Estimated by Web-Based Dietary Assessment Methods and Usability Using Dietary Records or 24-h Dietary Recalls: A Scoping Review.

The goal was to summarize studies comparing the accuracy of web-based dietary assessments with those of conventional face-to-face or paper-based assessments using 24-h dietary recall or dietary record methods in the general population. Using two databases, mean differences and correlation coefficients (CCs) for intakes of energy, macronutrients, sodium, vegetables, and fruits were extracted from each study independently by the authors. We also collected information regarding usability from articles reporting this. From 17 articles included in this review, the mean dietary intake differences in the web-based dietary assessment compared to conventional methods, were -11.5-16.1% for energy, -12.1-14.9% for protein, -16.7-17.6% for fat, -10.8-8.0% for carbohydrates, -11.2-9.6% for sodium, -27.4-3.9% for vegetables, and -5.1-47.6% for fruits. The CC was 0.17-0.88 for energy, protein, fat, carbohydrates, and sodium, and 0.23-0.85 for vegetables and fruits. In three out of four studies reporting usability, more than half of the participants preferred the web-based dietary assessment. In conclusion, % difference and CC of dietary intake were acceptable in both web-based dietary records and 24-h dietary recalls. The findings from this review highlight the possibility of wide-spread application of the web-based dietary assessment in the future.

Diet Quality and Its Relationship with Weight Characteristics in Pregnant Japanese Women: A Single-Center Birth Cohort Study.

Maternal underweight and inadequate gestational weight gain (GWG) are problems in Japan. However, increases in food intake aimed at weight gain alone are not sufficient for mother-child health. This study assessed diet quality based on the 3-day dietary records of pregnant women in an urban area of Japan in order to show the importance of evaluating diet quality, using the Nutrient-Rich Food Index 9.3 (NRF9.3), which is one metric based on nutrition profiling, and the Japanese Food Guide Spinning Top (JFGST). After excluding misreporters of energy intake, we stratified women (n = 91) by pre-pregnancy body mass index (BMI) and determined energy intake, diet quality status, and their relationship with GWG. Intakes of carbohydrate-containing staple foods, vegetable dishes, and fruit were insufficient regardless of BMI. Most of the underweight women with inadequate GWG had insufficient energy intake but high diet quality, as assessed by NRF9.3. In contrast, most women who consumed energy within the recommended range had low diet quality and gained weight at inappropriate levels. These results highlight the importance for pregnant Japanese women to maintain diet quality through a nutrient-dense diet, while simultaneously increasing energy intake after evaluation of their individual diet quality.

Global Comparison of Nutrient Reference Values, Current Intakes, and Intake Assessment Methods for Sodium among the Adult Population.

Excess sodium intake is a risk factor for non-communicable diseases (NCDs), such as cardiovascular diseases and hypertension. Therefore, many countries have set nutrient reference values for sodium, specifically for the prevention of NCDs, and intake is routinely monitored by nutrition surveys. In this review, we aimed to compare the global nutrient reference values and national intakes of sodium, along with the methods of intake assessment used. Data were obtained for Australia, Canada, Ireland, Japan, the UK, the US, and the European Food Safety Authority (EFSA), where information was accessible online in English or Japanese. We collected the following information regarding sodium intake: the term used for reference values to prevent NCDs; year when reference values were established or revised; reference values to prevent NCDs; target NCDs; designation of nutrition survey; method for estimating intake; and average intake. The reference values ranged from 2,000 mg (Australia and EFSA) to 2,953 mg (Japan). Sodium intake ranged from 2,431 mg (Australia) to 3,958 mg (Japan). Out of seven countries/institutions, five used dietary assessment, and two used sodium urinary excretion for estimating dietary sodium intake. Among the dietary assessment methods, the 24-h dietary recall was most frequently used. National sodium intake exceeded the reference values in all countries, and reduction of sodium intake remains a global challenge.

Response to antiviral therapy for chronic hepatitis C and risk of hepatocellular carcinoma occurrence in Japan: a systematic review and meta-analysis of observational studies.

In Japan, hepatocellular carcinoma (HCC) is a leading cause of cancer mortality and hepatitis C virus infection is a major cause of HCC. We conducted a systematic review and meta-analysis of published studies evaluating patient response to antiviral therapy for chronic hepatitis C on the risk of HCC occurrence in Japan. Articles were searched using terms determined a priori through PubMed, screened by title and abstract, and selected by full-text assessment according to criteria determined a priori, including HCC occurrence in response to interferon (IFN)-based or IFN-free therapy, Japanese study, and 2 or more years of follow-up. We excluded studies on HCC recurrence. We calculated the pooled estimate of the crude incidence rate ratio with data from the selected studies using the person-years method with Poisson regression model and pooled estimate of the hazard ratio adjusted for potential confounders reported by the studies using a random effects model. A total of 26 studies were identified, all of which examined only IFN-based therapy as a result of the selection process. The pooled estimate (95% confidence interval [CI]) of 25 studies was 0.37 (0.33-0.43) for sustained virologic response (SVR) and 1.70 (1.61-1.80) for non-SVR for the HCC incidence rate per 100 person-years, and 0.22 (0.19-0.26) for the incidence rate ratio (SVR vs. non-SVR). The pooled estimate of the hazard ratio (95% CI) of HCC incidence adjusted for potential confounders of 8 studies was 0.25 (0.19-0.34). SVR to interferon therapy for chronic hepatitis C reduces the risk of HCC occurrence.

The Relationship between Mental and Physical Minor Health Complaints and the Intake of Dietary Nutrients.

Presenteeism is a problem that needs to be solved urgently, both for individual workers and for society overall. In this report, we propose the concept of MHC, which refers to mild mental and physical complaints subjectively perceived by individuals that are not caused by illness. We also planned to examine what kind of physical and mental disorder MHC is and whether food is effective as a method of self-care for MHC. First, we conducted "the comprehensive survey to establish an integrated database of food, gut microbiome, and health information" (the "Sukoyaka Health Survey") and obtained data on psychosomatic disorders and intakes of dietary nutrients. As a result, through factor analysis and item response theory analysis, we found the following specific examples of MHC: lack of vigor, irritability, fatigue, and somatic complaints. In addition, analysis of the relationship between these four MHC levels and the intake dietary nutrients indicated that they are closely related and that MHC levels can be improved by consuming sufficient amounts of multiple nutrients.

Monitoring the Consumption of Vegetables among OECD Countries, Including Japan.

Increasing intakes of vegetables are associated with risk reduction in various non-communicable diseases, especially cardiovascular disease. In order to compare the proportion of daily vegetable intake among adults from these 30 Organization for Economic Co-operation and Development (OECD) countries as well as Japan, we applied data from the OECD website and the 2017 National Health and Nutrition Survey, Japan (NHNS-J). The figures for Australia, Israel, Korea, New Zealand, and the United States exceeded 80%, where survey questions in these countries asked the amount of intake, instead of the frequency of intake. In Japan, results from the one-day dietary record showed that 99.2% of adults consumed vegetables on the survey day; however, this decreased to 66.3% when assessed by a qualitative question. Proportion of daily vegetable intake as well as average intake amount was higher among those aged 60 y or older. Health policies to increase vegetable intake should target younger age groups to promote health in future generations, in Japan.

Optimal Diet for Achieving Favorable Pregnancy Outcomes in East Asian Women-A Literature Review.

Ensuring nutritional adequacy during pregnancy is one of the necessary factors to achieve favorable pregnancy outcomes. In order to clarify the current optimal diet for achieving favorable pregnancy outcomes among East Asian women, we conducted a systemic literature review. English and Japanese articles were searched using PubMed and Igaku Chuo Zasshi. A total of 167 papers were retrieved, and six papers were finally selected for review. Five studies were conducted prospectively, and one was a case-control study. No significant associations were observed between dietary intakes and infant birthweight, but low intakes of fat and vitamin E were associated with preterm birth risk. Maternal diet with various food groups including vegetables was associated with higher birthweight and lower risk of preterm birth. A balanced diet with a combination of diverse food groups may be effective in achieving favorable pregnancy outcomes.