Kanako Deguchi

BACKGROUND: Accurate estimation of energy requirements is essential for appropriate nutritional therapy. Resting energy expenditure (REE) predictive equations are derived from specific populations and may therefore contain systematic individual-level biases when applied in different clinical settings. In this pilot exploratory study, we compared REE measured by portable indirect calorimetry with estimates obtained using multiple predictive methods in Japanese adults and characterized their association, absolute agreement, and error structure. METHODS: Thirty-six university staff members and students were enrolled. The association and absolute agreement between REE measured by portable indirect calorimetry and estimates obtained using four predictive methods (Harris-Benedict, DRIs, Cunningham, and Ganpule) were evaluated using Spearman's rank correlation coefficients, ICC(2,1), and Bland-Altman analyses. For equations demonstrating significant proportional bias, multivariate linear regression analyses were additionally performed using residual estimation error, calculated as (predicted REE-measured REE)/measured REE × 100, as the dependent variable. RESULTS: Participants included 16 men and 20 women, with a mean age of 28.9 ± 10.3 years and BMI of 22.1 ± 3.1 kg/m2. Spearman's rho ranged from 0.750 to 0.800, and ICC(2,1) estimates ranged from 0.736 to 0.766. Mean biases (predicted minus measured REE) were 50.7 kcal/day (95% CI, -20.1 to 121.4) for Harris-Benedict, -73.1 kcal/day (95% CI, -148.8 to 2.6) for DRIs, -94.7 kcal/day (95% CI, -161.7 to -27.8) for Cunningham, and -90.6 kcal/day (95% CI, -161.1 to -20.2) for Ganpule. The corresponding proportions of predictions within ±10% of measured REE were 41.7% (95% CI, 27.1-57.8%), 50.0% (95% CI, 34.5-65.5%), 55.6% (95% CI, 39.6-70.5%), and 52.8% (95% CI, 37.0-68.0%), respectively. Multivariate analyses suggested greater underestimation in females and a shift toward overestimation with higher BMI. CONCLUSIONS: Despite moderate-to-strong rank associations with measured REE, Bland-Altman analysis revealed proportional bias in three of the four predictive methods that was not apparent from the correlation coefficients alone. Exploratory analyses suggested that sex and BMI should be considered when interpreting the direction of prediction error. Because the precision of the limits of agreement was restricted by the small sample size, larger studies are needed to estimate individual-level agreement more precisely and to examine these error patterns in older adults and individuals with acute or chronic diseases.

Background: Dietary diversity, commonly assessed using the Shannon index, reflects dietary structure and food-group variety. However, whether dietary diversity is more closely associated with demographic characteristics or lifestyle-related factors remains unclear. Objective: To examine associations between dietary diversity based on 10 food groups and demographic and lifestyle-related factors among Japanese corporate employees. Methods: This cross-sectional study analyzed data from 925 company employees aged 20-59 years. The Shannon index was calculated from 10 food groups. Associations with age, sex, body mass index (BMI), workplace location, occupation, household composition, home cooking, and lunch type were evaluated using analysis of variance, analysis of covariance (ANCOVA), and permutational multivariate analysis of variance (PERMANOVA). Results: Dietary diversity was more closely associated with lifestyle-related factors, particularly household composition and home cooking, than with demographic characteristics. Individuals living alone exhibited lower Shannon index values than those living in multiperson households. Notably, home cooking was associated with greater dietary diversity among participants in multiperson households, whereas no such association was observed among individuals living alone. PERMANOVA analyses also suggested differences in dietary structure according to household composition. Conclusions: Household composition may influence dietary structure and may modify the association between home cooking and dietary diversity. These findings suggest that determinants of dietary diversity may be context-dependent.

Background: Underweight status is common among young women in Japan and has been linked to impaired glucose tolerance, but its long-term association with HbA1c trajectories remains unclear. This study examined whether body size history in the twenties is associated with subsequent HbA1c trajectories across adulthood. Methods: We analyzed health check-up data from Fujita Health University, collected between 2003 and 2025. Participants were classified as normal weight in the twenties (NW20s), underweight at least once in the twenties (UW20s_ever), or overweight at least once in the twenties (OW20s_ever), excluding mixed underweight/overweight histories. Eligible individuals had at least 5 years of follow-up, at least five BMI and HbA1c measurements, and at least one BMI record between ages 20 and 29 years. HbA1c trajectories were evaluated using sex-stratified linear mixed-effects models. Kaplan-Meier and Cox regression analyses were used to assess the risk of first reaching HbA1c ≥ 5.6%. Results: A total of 2923 participants were included in the trajectory analysis. For the time-to-event analysis, 2753 participants were included after exclusion of 170 participants with HbA1c ≥ 5.6% at study entry. Body size history in the twenties was associated with distinct, sex-specific HbA1c trajectories. OW20s_ever showed persistently higher HbA1c levels in both women and men, but the local slope of HbA1c was greater at ages 35 and 45 years in women and at age 25 years in men. In contrast, UW20s_ever showed lower HbA1c levels than NW20s at ages 25 and 35 years only in women. In complementary time-to-event analyses, OW20s_ever was associated with a higher risk of HbA1c ≥ 5.6% in both women and men (women: HR 1.37, 95% CI 1.06-1.76, p = 0.016; men: HR 1.81, 95% CI 1.41-2.32, p < 0.001), whereas UW20s_ever was associated with a lower risk only in women (HR 0.81, 95% CI 0.67-0.98, p = 0.028). Conclusions: Underweight and overweight history in the twenties are not simply mirror-image exposures but rather have sex-dependent and asymmetric associations with later HbA1c regulation.

BACKGROUND: Underweight (BMI < 18.5 kg/m2) remains prevalent among young Japanese women but lacks standardized measurement approaches. We compared four analytical methods and identified discrepancies. METHODS: A retrospective analysis of 883 underweight women aged 20-29 years followed for 6.1 ± 4.2 years was performed. We compared (1) year-to-year transitions, (2) state occupancy, (3) the Aalen-Johansen estimator, and (4) Kaplan-Meier Survival Analysis. We performed bidirectional flow analysis quantifying inflow/outflow rates, BMI distribution analysis, and time-weighted classification. RESULTS: Methods 1 and 4 showed 31-point discrepancies (78.1% vs. 47.1% in women). In bidirectional flow, inflow exceeded outflow at ages 22-27 (35.7%/yr vs. 20.7%/yr, outflow/inflow ratio: 0.58), balanced at ages 27-37 (ratio: 1.02) and showed outflow-dominant pattern at ages 37-47 (ratio: 4.92). BMI clustered at 18.0-19.0 kg/m2 (42.7%); 69.4% crossed the threshold once. Time-weighted classification revealed four phenotypes: persistent (≥75% time underweight; 40.1%, BMI: 17.54 kg/m2), moderate (50-74%; 17.6%, BMI: 18.40 kg/m2), intermittent (25-49%; 17.6%, BMI: 18.97 kg/m2), and transient (<25%; 24.8%, BMI: 19.49 kg/m2). The moderate + intermittent group showed yo-yo phenotypes (35.2%). CONCLUSIONS: Underweight in young Japanese women should be viewed as a heterogeneous dynamic nutritional state. The methodological discrepancy, threshold crossing, and phenotypic classification show that BMI-defined underweight comprises distinct patterns. Cross-sectional data evaluation may lead to incorrect assessments. Future research examining relationships between longitudinal low body weight subgroups and clinical outcomes could identify at-risk populations within the underweight group.

Background: Medical nutrition therapy (MNT) is crucial for diabetes management. This study evaluated a hands-on nutrition education program that incorporated cooking demonstrations for glycemic control, anthropometrics, and dietary behavior over a 2-month period. Methods: Nineteen type 2 diabetes patients (four males and 15 females; 79% female) participated. The median [IQR] age was 70.0 [65.5–73.0] years; the duration of diabetes was 12.0 [8.5–14.0] years; the body mass index (BMI) was 24.3 [21.05–27.90] kg/m2, and the baseline HbA1c level was 6.90 [6.55–7.50%]. Approximately 20–25% of patients used injectable therapies. Pre- and post-treatment comparisons were performed via Wilcoxon signed-rank tests, while effect sizes were quantified via rank–biserial correlation (RBC). Results: In females (n = 15), carbohydrate intake decreased significantly (RBC = −0.583; p = 0.050). The protein levels per 1000 kcal exhibited a strong positive effect (RBC = 0.550; p = 0.065). HbA1c levels improved significantly (overall: RBC = −0.689 and p = 0.009; females: RBC = −0.725 and p = 0.014), and while body fat increased significantly (overall: RBC = 0.979 and p &lt; 0.001; females: RBC = 0.983 and p &lt; 0.001), the skeletal muscle index tended to decrease in females (RBC = −0.333; p = 0.268). Conclusions: Short-term hands-on nutrition education resulted in significant HbA1c improvement and dietary behavior changes but was accompanied by body composition deterioration. The findings of this study clarify the potential risks of nutritional interventions in elderly diabetic patients and provide important insights for improving future programs.