Ribeka Takachi

Background/Objectives: Existing methods for assessing the intake of vegetables and fruits have limitations. This study aims to investigate the number of measurements required to screen individuals with insufficient usual vegetable intake or total fruit and vegetable intake using urinary potassium excretion estimated from spot urine samples, a non-invasive and simple biomarker. Methods: A total of 97 women aged 18–24 years provided a 12-day dietary survey, four 24 h urine collections, and three timed spot urine samples per day, collected in a duration of 4 days. Using the dietary surveys as a reference, we evaluated the number of spot urine samples required and their screening performance for identifying individuals whose vegetable intake or total fruit and vegetable intake was below the study population mean. Screening performance was assessed by receiver operating characteristic analysis and the area under the curve (AUC). Results: For vegetable intake, the AUCs were >0.70 when either a single spot urine sample was collected at the second urine void after waking or ≥2 spot urine samples were collected at arbitrary time points. For total fruit and vegetable intake, AUCs were >0.70 when using a single spot urine sample collected at the second void after waking up. Conclusions: These findings suggest that a time-specific single spot urine sample (i.e., the second urine void after waking) or ≥2 spot urine samples collected at arbitrary time points may help in screening individuals with habitually insufficient vegetable intake.

Background: More research is needed to clarify the health effects of dietary carotenoid intakes, and this requires the use of high-quality assessments of habitual dietary intake. Cohort studies from the Tohoku Medical Megabank Organization included a self-administered food frequency questionnaire (TMM-FFQ) for community-dwelling adults. This study evaluated the validity of carotenoid intakes derived from the TMM-FFQ using serum carotenoid concentrations as the gold standard.Methods: In Miyagi Prefecture, 88 men and 124 women aged ≥20 years voluntarily agreed to participate in the study and provided completed TMM-FFQs and blood samples in 2019 and 2021. Carotenoids examined included α-carotene, β-carotene, β-cryptoxanthin, and lycopene. Intraclass correlation coefficients (ICCs) were calculated to assess correlations between serum concentrations in 2019 and 2021. Spearman’s rank correlation coefficients were calculated to evaluate the correlations between energy-adjusted dietary carotenoid intakes from the TMM-FFQ in 2021 and the average serum carotenoid concentrations in 2019 and 2021, with correction for the attenuating effect of random within-individual variation.Results: The ICCs between serum concentrations over the 2 years were >0.50 for all carotenoids. Among men, correlation coefficients were 0.33 for α-carotene, 0.42 for β-carotene, 0.50 for β-cryptoxanthin, and −0.09 for lycopene. Among women, the coefficients were lower than those for men, except for lycopene: 0.11 for α-carotene, 0.23 for β-carotene, 0.21 for β-cryptoxanthin, and 0.28 for lycopene.Conclusions: The TMM-FFQ demonstrated reasonable validity for assessing intakes of α-carotene, β-carotene, and β-cryptoxanthin among men, but not among women, in the TMM cohort studies when using serum concentrations as the gold standard.

Background: One of the factors for not achieving a reduced salt diet may be the difficulties in screening individuals according to their quantitative salt consumption. Accordingly, we examined the performance of the simplified salt check sheet (13 items) as a quantitative tool for screening excessive salt intake by comparing with the salt intake amount measured by 24-hour urinary sodium (salt equivalent g/day) excretion.Methods: One hundred fifty-four participants (57 males and 97 females) from Kanagawa, Tokyo, and Nara prefectures in Japan were included. In this study, which the design is a cross-sectional validation study, the salt intake amount was used as a diagnostic criterion, and corresponding receiver operating characteristic (ROC) curves were prepared based on the sensitivity and specificity of each score of the salt check sheet.Results: The average salt intake were 13.5 and 10.2 g/day for males and females, respectively. When using the total score, among males, the area under the ROC curve (AUC) was moderate (0.702 [95% CI, 0.543-0.862]), confirming its value as a diagnostic tool for salt intake of ≥10 g/day. In females, the AUCs were low for any criteria. When score calculation item was limited to three that contributed to the higher salt intake in this population, the AUC for ≥10 g salt/day was moderate (0.700 [95% CI, 0.595-0.805]).Conclusions: The salt check sheet was found to be useful in screening for excessive salt intake only in males. For females, it was suggested that it could be used only when three specific items are used.

Background: Evidence on factors influencing the association between physical activity (PA) and knee osteoarthritis (KOA) is scarce. The present study aimed to examine this association and explore interactions of PA with sex and age in relation to KOA in Japanese adults.Methods: This 11-year cohort study included 10,876 community-dwelling individuals aged 40–74 years in Murakami City (Niigata Prefecture, Japan). Data were collected using a self-administered questionnaire (2011–2013). Exposures were self-reported PA levels, and the outcome was clinically diagnosed KOA. Covariates included demographic factors, body size, lifestyle habits, and disease history. Cox proportional hazards models were used to estimate hazard ratios (HRs).Results: The mean age of participants was 58.0 years. Over a mean follow-up period of 11.1 years, 840 cases of KOA were observed. High total PA levels were associated with a greater KOA risk (P for trend <0.0001), with the highest quartile showing a higher hazard (HR=1.52, 95%CI:1.23–1.87) than the lowest (reference). This association was observed in both males (HR=2.01, 95%CI:1.39–2.93) and females (HR=1.30, 95%CI:1.01–1.66), with a P for interaction of 0.0219. In addition, the association was more pronounced in younger participants (<55 years; HR=2.07, 95%CI:1.25–3.43) and attenuated in older age groups, with a P for interaction of 0.0278. Non-leisure-time PA showed a similar association with KOA as total PA, whereas leisure-time PA did not.Conclusion: High total and non-leisure-time PA levels were associated with increased KOA risk, and these associations interacted with sex and age in middle-aged Japanese adults.

Background: Physical activity (PA) levels are inversely associated with hip fracture risk, but whether this is the case for other types of fractures, especially vertebral fractures, is unclear. The present study aimed to examine whether PA levels are associated with osteoporotic fracture risk in community-dwelling people.Methods: This cohort study analyzed 13,558 Japanese people aged 40–74 years (6,756 women and 6,802 men). Information on demographic characteristics, body size, lifestyle, and disease history was obtained by a self-administered questionnaire conducted in the 2011–2013 baseline survey. Levels of total PA excluding sleep, sitting, and other sedentary activities (TPA) were estimated by the metabolic equivalents score (MET-h/d). Incident limb fractures (distal radius, humeral neck, and hip) and vertebral fractures were identified in medical records. A Cox proportional hazards model was used to calculate hazard ratios (HRs).Results: During a mean follow-up period of 12.1 years, 966 fractures occurred (725 in women and 241 in men). Higher TPA levels were associated with a lower hazard of limb fracture (P for trend=0.0244), with the highest quintile having a lower HR (HR=0.67; 95%CI, 0.49–0.90) than the reference (lowest quintile). Higher LTPA levels were associated with a lower hazard of limb fracture (P for trend=0.0077), with the highest level having a lower HR (HR=0.73; 95%CI, 0.58–0.92) than the reference. No PA measures were associated with vertebral fracture.Conclusion: Higher levels of PA of any type are associated with a low risk of limb fracture, but not clinical vertebral fracture, in Japanese adults.

Although folate is essential for preconception care and reproductive health, non-invasive and valid methods for screening inadequate dietary folate intake are lacking. Urinary potassium excretion, a recovery biomarker of potassium intake, can be used as a proxy for dietary folate intake if the main sources of dietary folate and potassium are the same. This study examined the accuracy of screening using urinary potassium excretion as a proxy for inadequate dietary folate intake. Participants comprised 104 female university students who completed 3-d weighed food records (3dWFR) and 24-h urine collection on the third day of 3dWFR in April–July between 2019 and 2022. The major sources of dietary folate and potassium were identified, and the correlation coefficients between their intake and urinary potassium excretion were calculated. The area under the curve (AUC) and 95% confidence interval (CI) were calculated using receiver operating characteristic analysis. Vegetables were the food groups that contributed the most to dietary folate intake (42.7%) and potassium intake (28.9%). The correlation coefficient (r=0.57, p0.5 lower limit of 95% CI). These findings indicate that urinary potassium excretion can be used as a proxy indicator to screen for individuals with inadequate dietary folate intake.

Background: The Tohoku Medical Megabank Project has initiated the Birth and Three-Generation Cohort Study (TMM BirThree Cohort Study) including genomic and omics investigations, and conducted a self-administered food frequency questionnaire with the response option “constitutionally unable to eat or drink it” for individual food items (TMM-FFQ) for pregnant women. This study evaluated the validity of the TMM-FFQ among pregnant women.Methods: Participants comprised 122 pregnant women aged ≥20 years residing in Miyagi Prefecture who completed weighed food records (WFRs) for 3 days as reference intake and the TMM-FFQ during mid-pregnancy. Correlations between nutrient or food group intakes based on the WFR and the TMM-FFQ were calculated using Spearman’s rank correlation coefficients (CCs), adjusting for energy intake and correcting for random within-individual variation of WFR. Cross-classification was also conducted according to quintiles using the WFR and TMM-FFQ data.Results: The percentages of participants who chose the “constitutionally unable to eat or drink it” option were >3% for seven food and drink items. CCs were >0.30 for 31 nutrients; the median across energy and 44 nutrients was 0.41. CCs were >0.30 for 14 food groups; the median across 20 food groups was 0.35. The median percentages of cross-classification into exact plus adjacent quintiles and extreme quintiles were 63.1% and 3.3% for energy and nutrients and 61.9% and 4.1% for food groups, respectively.Conclusions: The validity of the TMM-FFQ compared with the WFR was reasonable for certain nutrients and food groups among pregnant women in the TMM BirThree Cohort Study.

Repeating food frequency questionnaires (FFQs) within the same population was reported to improve the validity of correlation coefficient (CC). However, the enhancement of validity in ranking agreement remains underreported. Herein, we assessed the validity of energy and nutrient intake es-timates using single and multiple FFQs and their ability to rank individuals. 213 men and women aged ≥20 years were recruited from the residents participating in the Tohoku Medical Mega-bank Project (TMM) cohort studies; three FFQs were conducted in November each year from 2019 to 2021, with 12-day weighted food records (WFRs) as the reference method. Spearman's rank CCs were calculated between single or multiple FFQs estimates and those obtained through the 12-day WFR. Additionally, the ranking agreement was compared based on cross-classification. CCs between intake estimated using a single FFQ and 12-day WFR were moderate for several nutrients, with median CCs of 0.52 for men and 0.48 for women. CCs for multiple FFQs were slightly higher than that of single FFQ, with median CCs of 0.59 for men and 0.56 for women. Regardless of the number of FFQs, the proportion of subjects classified into the opposite extreme category was ≤5% for most nutrients. A single FFQ used for adults in the TMM cohort studies showed moderate validity. Estimates from multiple FFQs improved the accuracy slightly; nevertheless, this indicates that relying on a single FFQ is unlikely to result in a serious misclassifica-tion compared to using intake data from multiple FFQs over a relatively short period.