Hidetaka Hamasaki

Objective: To investigate whether self-reported sedentary time is independently associated with circulating sex steroid hormone concentrations in US adults, with analyses stratified by sex and adjusted for handgrip strength. Design: Cross-sectional analysis incorporating the NHANES complex sampling design. Participants: Adults aged 18 years or older from NHANES 2013-2014. Women using oral contraceptives or hormone replacement therapy were excluded. Final sample: 3,358 adults (men: n = 2,480; women: n = 878). Measurements: Sedentary time (PAD680, minutes/day). Serum total testosterone (TT), free testosterone (FT, Vermeulen formula), estradiol, and SHBG were natural log-transformed. Survey-weighted linear regression was performed with four sequential models: unadjusted (Model 1); age and BMI-adjusted (Model 2); adjusted including age, BMI, race/ethnicity, education, smoking, alcohol, sleep, depressive symptoms, and cardiovascular disease history (Model 3); and additionally adjusted for handgrip strength (Model 4). Results: Among men, sedentary time was inversely associated with log-TT in Model 1 (β = −0.014, 95% confidence interval (CI): −0.0231 to −0.005, p = 0.005), Model 2 (β = −0.0095, 95% CI: −0.0182 to −0.0009, p = 0.033), Model 3 (β = −0.0117, 95% CI: −0.0216 to −0.0018, p = 0.024), and Model 4 (β = −0.0114, 95% CI: −0.0211 to −0.0017, p = 0.024). Consistent findings were observed for log-FT (Model 1: β = −0.0132, 95% CI: −0.0206 to −0.0058, p = 0.002; Model 2: β = −0.0091, 95% CI: −0.0157 to −0.0026, p = 0.01; Model 3: β = −0.012, 95% CI: −0.0189 to −0.005, p = 0.002; Model 4: β = −0.0116, 95% CI: −0.0188 to −0.0044, p = 0.004). Analyses in women yielded wide confidence intervals for all outcomes and results should be considered inconclusive given the limited sample size. Conclusions: Sedentary time is inversely associated with TT and FT in men, independent of age, adiposity, and muscular fitness. These results are consistent with sedentary behavior as a potentially modifiable behavioral correlate of male androgenic status; the present analysis extends prior binary testosterone deficiency analyses by using continuous hormone concentrations.

Aims: Sarcopenia and sarcopenic obesity are associated with increased risks of cardiovascular (CV) disease and mortality. This study examined the associations of body composition and daily physical activity with mortality, CV events and cancer in patients with diabetes. Methods: This prospective cohort study included patients with diabetes treated at a specialised clinic in Japan between January 2018 and March 2023. Body composition, including visceral adipose tissue (VAT), was assessed by bioelectrical impedance analysis. Daily physical activity was evaluated using the non-exercise activity thermogenesis (NEAT) questionnaire, and handgrip strength (HGS) was measured by dynamometry. Cox proportional hazards models were used to assess associations with mortality, CV events, and cancer. Results: Among 2,024 patients (mean age 63.0 years, BMI 24.6 kg/m^2, HbA1c 7.8%), NEAT, HGS, and VAT were not independently associated with all-cause mortality. Higher VAT was associated with increased cancer risk (HR 1.485; 95% CI 1.101-2.003; p = 0.009). Higher HGS was inversely associated with CV event risk (HR 0.951; 95% CI 0.919-0.984; p = 0.004). NEAT was not associated with any outcome. Conclusions: Higher VAT was associated with increased cancer risk, whereas higher HGS was protective against CV events. Incorporating body composition and HGS assessments into clinical practice may improve risk stratification and management in patients with diabetes.

Background: Total testosterone (TT) is the most widely studied androgen in mortality research, but estimated free testosterone (FT), the biologically active unbound fraction, may more accurately reflect androgen bioavailability. Whether FT is independently associated with all-cause mortality in men and women from a nationally representative US sample remains uncertain. Methods: We conducted a prospective cohort analysis using NHANES 2013–2014 linked to the National Death Index through December 31, 2019 (maximum follow-up 7.1 years). The analytic sample comprised 3,353 adults (2,477 men; 876 women); women receiving oral contraceptives or hormone replacement therapy were excluded. FT was estimated using the Vermeulen equation. Survey-weighted Cox proportional hazards models were fitted separately by sex, adjusting for age, BMI, race/ethnicity, lifestyle factors, depressive symptoms, and cardiovascular disease history; handgrip strength was added in a final model. Results: During a median follow-up of 5.9 years, 239 all-cause deaths occurred. Each log-unit increase in FT was associated with lower all-cause mortality in both men (HR 0.609, 95% CI 0.458–0.811, p<0.001) and women (HR 0.447, 95% CI 0.284–0.703, p=0.005) after multivariable adjustment, whereas TT was not independently associated with mortality in men after full adjustment (HR 0.840, p=0.201). Neither hormone was independently associated with cardiovascular mortality after multivariable adjustment. Findings were consistent across sensitivity analyses. Conclusions: FT, but not TT, was independently associated with all-cause mortality in men; findings in women were directionally consistent but limited by the small number of events. These findings suggest that FT may provide more prognostic information than TT in mortality research.

The obesity paradox describes a counterintuitive phenomenon where overweight or mildly obese individuals with chronic diseases show better survival compared to those with normal weight. While this paradox has been reported in conditions such as heart failure and type 2 diabetes, its presence in type 1 diabetes (T1D) remains uncertain. This mini review summarizes current evidence from large cohort studies and a meta-analysis examining the association between body mass index (BMI) and clinical outcomes in individuals with T1D. Most findings do not support a protective effect of higher BMI; instead, both underweight and obesity are associated with increased risks of cardiovascular events and all-cause mortality. Notably, some evidence suggests that individuals with advanced diabetic nephropathy or chronic kidney disease (CKD) may show the lowest mortality at mildly elevated BMI levels. However, these observations may reflect the limitations of using BMI alone to evaluate obesity. Given that individuals with T1D often have reduced skeletal muscle mass, and that those with advanced diabetic complications or comorbidities such as CKD or cancer may develop cachexia, body composition analysis is essential. Accurate assessment of fat mass, muscle mass, bone mass, and water content is critical for understanding obesity-related risks. Future research should integrate body composition metrics to improve risk stratification in T1D.

Background: In rapidly aging societies like Japan, socioeconomic status (SES) plays a critical role in shaping older adults’ health behaviors. Disparities in SES influence access to healthcare, engagement in health-promoting activities, and the adoption of digital health technologies. This narrative review synthesizes current evidence on how SES affects health behaviors among older adults and highlights challenges in promoting equitable and sustainable healthcare in aging populations. Methods: A PubMed search was conducted for English-language articles published up to May 2025 using the keywords “socioeconomic status”, “older adults”, and terms related to health behaviors. Studies were included if they focused on individuals aged 65 or older and examined associations between SES and healthcare use, digital health, complementary and alternative medicine (CAM), supplements, or lifestyle behaviors. Results: A total of 24 articles were identified. Higher SES—typically measured by income, education, and occupation—was consistently associated with an increased use of preventive services, digital health tools, CAM, and healthier lifestyle behaviors such as diet, physical activity, and sleep. In contrast, lower SES was linked to healthcare underuse or overuse, digital exclusion, and less healthy behaviors. Structural and regional disparities often reinforce individual-level SES effects. Comorbidity burden and shifting health perceptions with age may also modify these associations. Conclusions: SES is a key determinant of health behavior in older adults. Policies should focus on redistributive support, digital inclusion, and SES-sensitive health system strategies to reduce disparities and promote healthy aging in super-aged societies.

Patient experience is a critical healthcare quality indicator, evolving from Patient Satisfaction (PS) and encompassing patients’ concrete healthcare experiences. It is increasingly vital in aging societies where collaborative efforts among patients, families, and healthcare professionals are essential. Studies suggest that enhanced patient experience leads to better adherence, outcomes, and patient safety. This paper reviews patient experience evaluations in older adults with diabetes through randomized controlled trial (RCT)-based findings. The author searched PubMed/MEDLINE, Embase, AMED, and CINAHL. The review focused on RCTs examining interventions affecting patient experience and PS in T2D/T1D patients aged ≥65. A total of 13 RCTs were eligible for this review. This review highlights studies on diabetes management in older adults, assessing the impact of health education, diabetes management programs, treatments, mHealth, and advanced insulin delivery systems. Early studies showed that education improved self-care but had a limited impact on glycemic control. Key findings include the effectiveness of experience-based education in improving HbA1c, the benefits of insulin therapy for elderly patients, and the value of structured peer-to-peer diabetes management programs in enhancing satisfaction. Patient adherence, satisfaction, and personalized support emerged as critical factors influencing diabetes management across various interventions. More recent trials involving mHealth demonstrated improvements in glycemic control and PS through automated data sharing and app-based support. Closed-loop insulin delivery studies reported reduced mental strain, improved glycemic control, and better quality of life, despite barriers such as device cost and occasional system limitations. These interventions highlight the potential of advanced technologies to enhance diabetes care, particularly for aging populations. Previous RCTs show that education, structured management programs, effective insulin therapies, and advanced digital treatments improve patient experience, though well-designed studies focusing on patient experience as a primary outcome are lacking. Developing patient experience assessment scales for aging diabetes patients and adapting healthcare systems to maximize patient experience amid digitalization trends are essential, warranting further research.