Machine learning reveals heterogeneous associations between environmental factors and cardiometabolic diseases across polygenic risk scores.

BACKGROUND: Although polygenic risk scores (PRSs) are expected to be helpful in precision medicine, it remains unclear whether high-PRS groups are more likely to benefit from preventive interventions for diseases. Recent methodological advancements enable us to predict treatment effects at the individual level. METHODS: We employed causal forest to explore the relationship between PRSs and individual risk of diseases associated with certain environmental factors. Following simulations illustrating its performance, we applied our approach to investigate the individual risk of cardiometabolic diseases, including coronary artery diseases (CAD) and type 2 diabetes (T2D), associated with obesity and smoking among individuals from UK Biobank (UKB; n = 369,942) and BioBank Japan (BBJ; n = 149,421). RESULTS: Here we find the heterogeneous association of obesity and smoking with diseases across PRS values, complicated by the multi-dimensional combination of individual characteristics such as age and sex. The highest positive correlations of PRSs and the exposure-related disease risks are observed between obesity and T2D in UKB and between smoking and CAD in BBJ (Spearman's ρ = 0.61 and 0.32, respectively). However, most relationships are weak or negative, suggesting that high-PRS groups will not necessarily benefit most from environmental factor prevention. CONCLUSIONS: Our study highlights the importance of individual-level prediction of disease risks associated with target exposure in precision medicine.

This study aimed to understand if people with a high genetic risk for certain diseases benefit more from preventive strategies. Using a machine-learning-based method, we analyzed data from large groups of people in the UK and Japan. We examined the risk of heart and metabolic diseases in relation to obesity and smoking. The results showed that the link between genetic risk and disease is complex and varies widely among individuals. Our results suggested that those with a high genetic risk for disease may not always benefit more from the prevention of obesity and smoking. This finding suggests that we need to consider more than risk in decisions on how to prevent diseases in individuals.

Machine Learning Approaches to Evaluate Heterogeneous Treatment Effects in Randomized Controlled Trials: A Scoping Review.

BACKGROUND: Estimating heterogeneous treatment effects (HTEs) in randomized controlled trials (RCTs) has received substantial attention recently. This has led to the development of several statistical and machine learning (ML) algorithms to assess HTEs through identifying individualized treatment effects. However, a comprehensive review of these algorithms is lacking. We thus aimed to catalog and outline currently available statistical and ML methods for identifying HTEs via effect modeling using clinical RCT data and summarize how they have been applied in practice. STUDY DESIGN AND SETTING: We performed a scoping review using pre-specified search terms in MEDLINE and Embase, aiming to identify studies that assessed HTEs using advanced statistical and ML methods in RCT data published from 2010 to 2022. RESULTS: Among a total of 32 studies identified in the review, 17 studies applied existing algorithms to RCT data, and 15 extended existing algorithms or proposed new algorithms. Applied algorithms included penalized regression, causal forest, Bayesian causal forest, and other meta-learner frameworks. Of these methods, causal forest was the most frequently used (7 studies) followed by Bayesian causal forest (4 studies). Most applications were in cardiology (6 studies), followed by psychiatry (4 studies). We provide example R codes to illustrate how to implement these algorithms. CONCLUSION: This review identified and outlined various algorithms currently used to identify HTEs and individualized treatment effects in RCT data. Given the increasing availability of new algorithms, analysts should carefully select them after examining model performance and considering how the models will be used in practice.

Understanding the daily life needs of older public assistance recipient subgroups in Japan: A qualitative study.

Transition from individual-level treatment to social-level intervention should be made to improve peoples daily living conditions for reducing health inequality, which is a major global public health concern. Older public assistance recipients in Japan are socially vulnerable and require healthcare, long-term care, daily living, and social care support. Understanding the diverse daily living needs among public assistance recipient subgroups would prompt the development of novel support measures in the welfare sector. Therefore, this study aimed to understand the daily life needs of older recipient subgroups (segments) created quantitatively in our previous study. We interviewed four caseworkers at municipal welfare offices in 2021; the interview data were analyzed using a qualitative descriptive method to describe the daily life needs of the five older recipient segments for each sex. Five themes of daily life needs were demonstrated: i) housing, ii) financial, iii) welfare service, iv) healthcare, and v) no daily life needs. Consequently, we identified the daily life needs of some older recipient segments, indicating the necessity for support interventions. Future research would help interview other professionals from various backgrounds to further understand the daily life needs of older recipient segments.

Community-level social capital and subsequent health and well-being among older adults in Japan: An outcome-wide longitudinal approach.

There is inconsistent evidence on the association between community-level social capital and the health or well-being of older adults. This study examined the association between community-level social capital and multidimensional health and well-being outcomes using an outcome-wide approach. We used data from the Japan Gerontological Evaluation Study, a nationwide cohort study of Japanese older adults (analytic samples: 47,227 for outcomes obtained from the long-term care insurance registry and 34,183 for other outcomes). We assessed three aspects of school-district-level community social capital in 2016 (civic participation, social cohesion, and reciprocity) and 41 subsequent health and well-being outcomes through 2019. We performed either a modified multilevel Poisson regression or a multilevel logistic regression analysis. We adjusted for pre-baseline characteristics, prior outcome values, and individual-level social capital from the 2013 wave. Even after Bonferroni correction, we found that community-level social capital was associated with some subsequent social well-being and physical/cognitive health. For example, community-level reciprocity was associated with a higher prevalence of taking a social role (Prevalence ratio [PR] = 1.03, 95% confidence interval [CI] = 1.02, 1.04) and undergoing health screening (PR = 1.03, 95% CI: 1.01, 1.04). There was modest evidence that community-level civic participation was associated with a higher competency of intellectual activity (PR = 1.01, 95% CI: 1.01, 1.02) and community-level social cohesion was associated with a reduced onset of functional disability (PR = 0.94, 95% CI: 0.90, 0.98). Community-level social capital may promote social well-being and some physical/cognitive health outcomes.

Continuous Support from the Same Public Health Nurse and Parental Perception and Use of Health Care Services: A Retrospective Observational Study.

OBJECTIVE: Continuity is considered essential for high-quality maternal and child health care services, but studies to show this effect on parental well-being are still rare. We studied whether receiving support from the same public health nurse has a beneficial effect on parental perceptions of health care professionals and the use of childcare support services. METHODS: Maternal and child health care services were provided by different nurses in a Japanese municipality until March 2019. From April 2019, all families with infants received continuous support from the same assigned nurse. A questionnaire covering parental perception and the use of services was sent by postal mail to 1,341 families with infants. The data were analyzed using χ2-test, t-test and logistic regression producing odds ratios (OR) with 95% confidence intervals (CI). RESULTS: Parental perceptions of the availability of professionals to discuss children's issues, the degree of understanding about available other childcare support services, the degree of utilizing other services, and satisfaction with health care services were higher in parents who received continuous support from the same assigned nurse compared to those who did not receive continuous support. Continuous support was associated with parental perceptions of the availability of professionals to discuss children's issues (OR = 1.97, 95% CI 1.34-2.91) and the degree of understanding about available other child-care support services (OR = 1.65, 95% CI 1.11-2.44) after adjusting the results for socioeconomic factors. CONCLUSIONS: Continuous support from the same assigned nurse has benefits for parents. This offers a cost-effective way to improve parental well-being.

Neighborhood Environments and Healthy Life Expectancy in Older Adults: A 6-year Longitudinal Cohort Study Based on Data from the Japan Gerontological Evaluation Study.

Introduction: A well-established association exists between health and neighborhood land use patterns, including parks, roads, and other physical environments, also called the built environment. Previous studies have demonstrated that the built environment influences health, particularly among older populations, because the scope of activities in such populations is limited. Herein, we investigated the association between specific neighborhood environments and the healthy life expectancy of older individuals. Methods: Data at two time points (2013 and 2019) from the Japan Gerontological Evaluation Study were used in this study. The study comprised a sample of 8,956 residents aged ≥65 years who were not certified for long-term care. Information on the presence or absence of eight types of neighborhood environments was collected using a questionnaire. A multistate life table analysis was conducted to determine the association between perceived neighborhood environments and healthy life expectancy. Results: Significant differences were observed in the "parks and sidewalks suitable for exercise and walking" category. The group that perceived "parks and sidewalks suitable for exercise and walking" had an approximately 1.2-year longer healthy life expectancy than the group that did not perceive such parks and sidewalks. In addition, individuals who lived within walking distance of a park were more physically active than those who did not. Conclusions: Safe, walkable neighborhoods with excellent parks may encourage physical activity among older adults and extend their healthy lifespan. Future research is warranted to identify the underlying mechanisms.

Incidence and clinical course of femoral localized periosteal thickening and atypical femoral fracture over a 10-year period in patients with autoimmune inflammatory rheumatic disease.

Atypical femoral fracture (AFF) is generally a rare complication of long-term use of bisphosphonate (BP); glucocorticoid (GC) use and Asian race are also risk factors. Femoral localized periosteal thickening (LPT, also termed "beaking") of the lateral cortex often precedes AFF. This cohort study investigated the incidence of LPT and AFF and their clinical courses over 10 yr in patients with autoimmune inflammatory rheumatic diseases (AIRDs) treated with BP and GC. The study population consisted of 121 patients with AIRDs taking BP and GC. LPT was screened by X-ray, and the LPT shape was evaluated. Prednisolone (PSL) dose was 10 (8-12) mg/d at enrollment and 9 (6-10) mg/d at the last observation. LPT was evident in 10 patients at enrollment and increased linearly to 31 patients (26%) at the last observation. AFF occurred in 9 femurs of 5 patients with LPT. All patients with AFF had bilateral LPT, and the prevalence of pointed type and LPT height were higher in the AFF-positive group than in the AFF-negative group. AFF occurred before BP discontinuation in 2 patients, 1 yr after BP discontinuation in 1, after BP discontinuation followed by 7 yr of alfacalcidol use in 1, and after switching from alfacalcidol to denosumab in 1. The prevalence rates of AFF and LPT associated with long-term BP use with concomitant use of GC (mostly PSL ≥ 6 mg/d) in Japanese patients with AIRD increased over time. The selection of long-term osteoporosis treatment for LPT-positive patients is difficult in some cases.

Quantitative evaluation of particle-binder interactions in ceramic slurries via differential centrifugal sedimentation.

In diverse materials science spanning from fine ceramics to lithium-ion batteries and fuel cells, the particle-binder interactions in slurries play a crucial role in governing the ultimate performance. Despite numerous efforts to date, quantitatively elucidating these hidden interactions has remained a longstanding challenge. Here, we demonstrate a dynamic approach to evaluate adsorptive interactions between ceramic particles and polymeric binders entangled in a slurry utilizing differential centrifugal sedimentation (DCS). Particles settling under a centrifugal force field impart significant viscous resistance on the adsorbed binder, leading to its detachment, influenced by particle size and density. This behaviour directly reflects the particle-binder interactions, and detailed DCS spectrum analysis enables the quantitative assessment of nano-Newton-order adsorption forces. An important finding is the strong correlation of these forces with the mechanical properties of the moulded products. Our results provide insight that forming a flexible network structure with appropriate interactions is essential for desirable formability.

Lithium inelastic cross-sections and their impact on micro and nano dosimetry of boron neutron capture.

Objective.To present a new set of lithium-ion cross-sections for (i) ionization and excitation processes down to 700 eV, and (ii) charge-exchange processes down to 1 keV u-1. To evaluate the impact of the use of these cross-sections on micro a nano dosimetric quantities in the context of boron neutron capture (BNC) applications/techniques.Approach.The Classical Trajectory Monte Carlo method was used to calculate Li ion charge-exchange cross sections in the energy range of 1 keV u-1to 10 MeV u-1. Partial Li ion charge states ionization and excitation cross-sections were calculated using a detailed charge screening factor. The cross-sections were implemented in Geant4-DNA v10.07 and simulations and verified using TOPAS-nBio by calculating stopping power and continuous slowing down approximation (CSDA) range against data from ICRU and SRIM. Further microdosimetric and nanodosimetric calculations were performed to quantify differences against other simulation approaches for low energy Li ions. These calculations were: lineal energy spectra (yf(y) andyd(y)), frequency mean lineal energyyF-, dose mean lineal energyyD-and ionization cluster size distribution analysis. Microdosimetric calculations were compared against a previous MC study that neglected charge-exchange and excitation processes. Nanodosimetric results were compared against pure ionization scaled cross-sections calculations.Main results.Calculated stopping power differences between ICRU and Geant4-DNA decreased from 33.78% to 6.9%. The CSDA range difference decreased from 621% to 34% when compared against SRIM calculations. Geant4-DNA/TOPAS calculated dose mean lineal energy differed by 128% from the previous Monte Carlo. Ionization cluster size frequency distributions for Li ions differed by 76%-344.11% for 21 keV and 2 MeV respectively. With a decrease in theN1within 9% at 10 keV and agreeing after the 100 keV. With the new set of cross-sections being able to better simulate low energy behaviors of Li ions.Significance.This work shows an increase in detail gained from the use of a more complete set of low energy cross-sections which include charge exchange processes. Significant differences to previous simulation results were found at the microdosimetric and nanodosimetric scales that suggest that Li ions cause less ionizations per path length traveled but with more energy deposits. Microdosimetry results suggest that the BNC's contribution to cellular death may be mainly due to alpha particle production when boron-based drugs are distributed in the cellular membrane and beyond and by Li when it is at the cell cytoplasm regions.

An interface tool to parametrize treatment plans for the TrueBeam radiotherapy system into TOPAS parameter control files for Monte Carlo simulation.

PURPOSE: The Monte Carlo (MC) method, the gold standard method for radiotherapy dose calculations, is underused in clinical research applications mainly due to computational speed limitations. Another reason is the time-consuming and error prone conversion of treatment plan specifications into MC parameters. To address this issue, we developed an interface tool that creates a set of TOPAS parameter control files (PCF) from information exported from a clinical treatment planning system (TPS) for plans delivered by the TrueBeam radiotherapy system. METHODS: The interface allows the user to input DICOM-RT files, exported from a TPS and containing the plan parameters, and choose different multileaf-collimator models, variance reduction technique parameters, scoring quantities and simulation output formats. Radiation sources are precomputed phase space files obtained from Varian. Based on this information, ready-to-run TOPAS PCF that incorporate the position and angular rotation of the TrueBeam dynamic collimation devices, gantry, couch, and patient according to treatment plan specifications are created. RESULTS: Dose distributions computed using these PCF were compared against predictions from commercial TPS for different clinical treatment plans and techniques (3D-CRT, IMRT step-and-shoot and VMAT) to evaluate the performance of the interface. The agreement between dose distributions from TOPAS and TPS (>98 % pass ratio in the gamma test) confirmed the correct parametrization of treatment plan specifications into MC PCF. CONCLUSIONS: This interface tool is expected to widen the use of MC methods in the clinical medical physics field by facilitating the straightforward transfer of treatment plan parameters from commercial TPS into MC PCF.

Promotive and protective effects of community-related positive childhood experiences on adult health outcomes in the context of adverse childhood experiences: a nationwide cross-sectional survey in Japan.

OBJECTIVE: Although adverse childhood experiences (ACEs) are associated with poor health in adulthood, positive childhood experiences (PCEs) can reduce the risk of negative health outcomes. This study aimed to investigate whether PCEs in the community (CPCEs, ie, trusted adults other than parents, supportive friends, belongingness to school, or community traditions) would have an independent effect on better health outcomes and moderate the association between ACEs and adult illnesses. DESIGN: Cross-sectional survey. SETTING: Data were gathered from a nationwide, cross-sectional internet survey conducted in Japan in 2022. PARTICIPANTS: This study included 28 617 Japanese adults aged 18-82 years (51.1% female; mean age=48.1 years). PRIMARY AND SECONDARY OUTCOME MEASURES: The associations among self-reported ACEs, CPCEs before the age of 18 years and current chronic diseases (eg, cancer and depression) were investigated using multivariable logistic regression models. RESULTS: CPCEs were associated with lower odds of adult diseases (such as stroke, chronic obstructive pulmonary disease (COPD), chronic pain, depression, suicidal ideation and severe psychological distress) after adjusting for ACEs. More CPCEs weakened the association between ACEs and adult diseases. Specifically, among those with ACEs, ≥3 CPCEs (vs 0-2 CPCEs) lowered the adjusted prevalence by ≥50% for stroke (2.4% to 1.2%), COPD (2.2% to 0.7%) and severe psychological distress (16.4% to 7.4%). CONCLUSION: CPCEs could reduce ACE-related risk of poor physical and mental health in later life. Early-life interventions that enhance PCEs in schools and/or neighbourhoods are recommended.

Heterogeneous Effects of Intensive Glycemic and Blood Pressure on Cardiovascular Events Among Diabetes by Living Arrangements.

BACKGROUND: Although living alone versus with others is a key social element for cardiovascular prevention in diabetes, evidence is lacking about whether the benefit of intensive glycemic and blood pressure (BP) control differs by living arrangements. We thus aim to investigate heterogeneity in the joint effect of intensive glycemic and BP control on cardiovascular events by living arrangements among participants with diabetes. METHODS AND RESULTS: This study included 4731 participants with diabetes in the ACCORD-BP (Action to Control Cardiovascular Risk in Diabetes-Blood Pressure) trial. They were randomized into 4 study arms, each with glycated hemoglobin target (intensive, <6.0% versus standard, 7.0-7.9%) and systolic BP target (intensive, <120 mm Hg versus standard <140 mm Hg). Cox proportional hazard models were used to estimate the joint effect of intensive glycemic and BP control on the composite cardiovascular outcome according to living arrangements. At a mean follow-up of 4.7 years, the cardiovascular outcome was observed in 445 (9.4%) participants. Among participants living with others, intensive treatment for both glycemia and BP showed decreased risk of cardiovascular events compared with standard treatment (hazard ratio [HR], 0.68 [95% CI, 0.51-0.92]). However, this association was not found among participants living alone (HR, 0.96 [95% CI, 0.58-1.59]). P for interaction between intensive glycemic and BP control was 0.53 among participants living with others and 0.009 among those living alone (P value for 3-way interaction including living arrangements was 0.049). CONCLUSIONS: We found benefits of combining intensive glycemic and BP control for cardiovascular outcomes among participants living with others but not among those living alone. Our study highlights the critical role of living arrangements in intensive care among patients with diabetes.

Regional Disparities in Hyperacute Treatment and Functional Outcomes after Acute Ischemic Stroke in Japan.

AIM: This study investigated the impact of rurality on acute ischemic stroke (AIS) outcomes, emphasizing the hyperacute phase, in which immediate care is crucial. METHODS: This retrospective cohort study analyzed data from a large Japanese hospital network covering AIS patients from 2013-2021, was analyzed. The focus was on patients admitted within 4.5 h of the onset, using the Rurality Index for Japan (RIJ) to categorize patients into rural or urban groups. This study examined treatment methods (intravenous thrombolysis [IVT] and mechanical thrombectomy [MT]) and functional outcomes measured using the modified Rankin Scale (mRS), where scores of 3-6 indicated poor outcomes. Multilevel logistic regression was used to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for poor outcomes baSed on rurality. The study also evaluated the population-attributable fraction (PAF) to estimate potential outcome improvements in urban settings. RESULTS: Of 27,691 patients, 17,516 were included in the total cohort and 4,954 in the hyperacute cohort. Urban patients constituted 73.7% (12,902), with higher IVT (5.2%) and MT (3.6%) rates than rural patients (4.1% IVT, 2.0% MT). Poor mRS outcomes were more common in rural areas than in urban areas, with adjusted ORs of 1.30 (1.18-1.43) in the total cohort and 1.43 (1.19-1.70) in the hyperacute cohort. The PAF for poor outcomes due to rural residency was 14.8% (0.5%-31.0%). CONCLUSION: This study demonstrated a notable association between rurality and poorer AIS outcomes in Japan, particularly in the hyperacute phase.

Depression Onset After a Spouse's Cardiovascular Event.

Importance: Although cardiovascular disease (CVD) is a known risk factor for depression, evidence is lacking regarding whether and to what extent a spouse's CVD is associated with the subsequent mental health of individuals. Objective: To examine the association between CVD onset in spouses and subsequent depression. Design, Setting, and Participants: This cohort study examined 277 142 matched married couples enrolled in the Japan Health Insurance Association health insurance program between April 2015 and March 2022, covering approximately 40% of the working-age population in Japan. Index individuals (primary insured) whose spouses (dependent) experienced incident CVD between April 2016 and March 2022 were 1:1 matched to controls whose spouses did not experience CVD. Matching was based on age, sex, income, or the onset date of the spouses' CVD. Data analysis was conducted from April 2016 to March 2022. Exposure: Spousal onset of CVD between fiscal years 2016 and 2021. The International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes were used to identify the composite CVD outcomes (stroke, heart failure, and myocardial infarction). Main Outcomes and Measures: Multivariate Cox proportional hazards models were used to investigate the association between spouses' new-onset CVD and individuals' depression, adjusting for sociodemographic characteristics and comorbidities of index individuals (diabetes, hypertension, and CVD) and spouses (diabetes, hypertension, and depression). Subgroup analyses were conducted according to sex, age, income levels, and history of CVD. Results: Among 277 142 matched pairs of married couples, 263 610 (95.1%) had a male index individual; the mean (SD) age of index individuals was 58.2 (10.2) years. A new onset of depression was observed in 4876 individuals (1.8%). In multivariable Cox models, there was an association between the spouse's CVD and the individuals' depression (hazard ratio, 1.13 [95% CI, 1.07-1.20]). The subgroup analysis found no evidence of heterogeneity in sex, age, income level, or CVD history. The results were consistent when additionally adjusted for health behaviors (smoking, alcohol consumption, physical activity, and use of antihypertensive drugs) and objectively measured physical health conditions (body mass index, blood pressure, cholesterol levels, glucose levels, and estimated glomerular filtration rate) (hazard ratio, 1.16 [95% CI, 1.06-1.28]). Conclusions and Relevance: In this nationwide cohort study of matched couples, a spouse's onset of CVD was associated with an increased risk of an individual's depression. These findings highlight the importance of preventive care for mental health disorders in individuals whose spouses experience incident CVD.

Modifiable risk factors of inequalities in hypertension: analysis of 100 million health checkups recipients.

Inequalities in health behaviors are thought to contribute to inequalities in hypertension. This study examined the extent to which modifiable mediating factors explain income inequalities in hypertension. This repeated cross-sectional study used data from National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) from 2009 to 2015. Those aged between 40 and 74 were enrollees in the Specific Health Checkups. Hypertension was defined as systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90, or the use of antihypertensive medication. The mediating effects of exercise, obesity, smoking, and alcohol drinking on the association between income, as an indicator of SES, and hypertension were determined by the Karlson-Holm-Breen (KHB) method. The mean age of the 68,684,025 men and 59,118,221 women was 54.7 (SD = 9.6) and 56.7 (SD = 10.0) years, respectively. Prevalence of hypertension was higher in the lowest income group (48.6% for men, 40.2% for women) than in the highest income group (33.3% for men, 21.5% for women). Inequalities tended to increase over time. Inequalities were larger among those who did not use antihypertensive medication. Modifiable risks explained 10.6% of the association between income and hypertension for men and 15.1% for women. In men, drinking and obesity explained 8.8% and 5.5% of the inequalities in hypertension, respectively. In women, obesity explained 18.8%. Exercise increased the proportion mediated over time. Smoking explained 5.5% among women taking antihypertensive medication. There were health inequalities in hypertension among Japanese adults, and the modifiable risk factors partially explained the inequalities.

Income Level and Impaired Kidney Function Among Working Adults in Japan.

Importance: Chronic kidney disease (CKD) is a major public health issue, affecting 850 million people worldwide. Although previous studies have shown the association between socioeconomic status and CKD, little is known about whether this association exists in countries such as Japan where universal health coverage has been mostly achieved. Objective: To identify any association of income-based disparity with development of impaired kidney function among the working population of Japan. Design, Setting, and Participants: This was a nationwide retrospective cohort study of adults aged 34 to 74 years who were enrolled in the Japan Health Insurance Association insurance program, which covers approximately 40% of the working-age population (30 million enrollees) in Japan. Participants whose estimated glomerular filtration rate (eGFR) had been measured at least twice from 2015 to 2022 were included in the analysis, which was conducted from September 1, 2021, to March 31, 2023. Exposure: Individual income levels (deciles) in the fiscal year 2015. Main Outcomes and Measures: Odds ratios were calculated for rapid CKD progression (defined as an annual eGFR decline of more than 5 mL/min/1.73 m2), and hazard ratios, for the initiation of kidney replacement therapy (dialysis or kidney transplant) by income level deciles in the fiscal year 2015. Results: The study population totaled 5 591 060 individuals (mean [SD] age, 49.2 [9.3] years) of whom 33.4% were female. After adjusting for potential confounders, the lowest income decile (lowest 10th percentile) demonstrated a greater risk of rapid CKD progression (adjusted odds ratio, 1.70; 95% CI, 1.67-1.73) and a greater risk of kidney replacement therapy initiation (adjusted hazard ratio, 1.65; 95% CI, 1.47-1.86) compared with the highest income decile (top 10th percentile). A negative monotonic association was more pronounced among males and individuals without diabetes and was observed in individuals with early (CKD stage 1-2) and advanced (CKD stage 3-5) disease. Conclusions and Relevance: The findings of this retrospective cohort study suggest that, even in countries with universal health coverage, there may be a large income-based disparity in the risk of rapid CKD progression and initiation of kidney replacement therapy. These findings highlight the importance of adapting CKD prevention and management strategies according to an individual's socioeconomic status, even when basic health care services are financially guaranteed.

Exploring social network typologies and their impact on health and mental well-being in older adults: Evidence from JAGES.

BACKGROUND: The types of social networks, their prevalence, and their relationship to health outcomes in older age have been different across countries and cultures. Most of the literature has focused on USA or in European countries and little is known about the social network typologies among older adults from Japan. This study aimed to identify these patterns of social network typologies and examine the differences in sociodemographic and related to health variables. METHODS: 23894 participants from the JAGES project (2019), aged 65 or older (M = 74.74, DT = 6.39) from Japan. Statistical analyses included Latent Profile Analysis (LPA) followed by ANOVAs, Chi square and multinomial logistic regressions tests to compare the profiles. RESULTS: Four profiles were identified: family (66.9%), spouse (16.6%), diverse (14.5%), and neighbor/others (1.9%). The profiles differ statistically (p < 0.001) in all sociodemographic characteristics and in the means of depression, loneliness, self-perceived health, and happiness. Compared with the "family" network, younger men, with fewer chronic illnesses but higher levels of depression and loneliness were more likely to be in the "spouse" profile, older women with lower socioeconomic status, but less lonely and happier in the "diverse" profile and adults who still working, have lower socioeconomic status and are less happy into the "neighbors/others" group. DISCUSSION: We discuss the differences between the profiles found, the potential differences with previous studies and the specific cultural Japanese nuances that may explain the characteristics of the network types founded.

Association between social support and ambulance use among older people in Japan: an empirical cross-sectional study.

BACKGROUND: Ambulance service demand and utilization are increasing worldwide. To address this issue, the factors that affect ambulance use must be identified. Few studies have examined factors that can intervene and thus reduce the frequency of ambulance use. This study aimed to examine the association between social support and ambulance use among older adults in Japan. We hypothesize that social support is associated with reduced ambulance use. METHODS: This cross-sectional study was conducted as part of the Japan Gerontological Evaluation Study. In December 2019 and January 2020, we collaborated with individuals aged 65 years or above with no long-term care needs. A total of 24,581 participants were included in the analysis. The objective and explanatory variables were ambulance use and social support, respectively. Binomial regression analysis was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Social support was associated with ambulance use. People who had no one to listen to their complaints or worries were significantly more likely to use ambulance services than those who did (OR [95% CI] = 1.26 [1.03-1.53]). People with no one to take care of them when they were ill were also significantly more likely to use ambulance services than those who had someone to provide care (1.15 [1.01-1.31]). Moreover, the results of binomial logistic regression analysis indicated that individuals who called an ambulance but were not hospitalized had significantly lower social support compared to those who did not call an ambulance. CONCLUSIONS: The results suggest that the presence and quality of social support play a significant role in ambulance use among older adults in Japan. Our findings can help policymakers to plan and implement strategies for reducing the burden on emergency medical care.

Living in public rental housing is healthier than private rental housing a 9-year cohort study from Japan Gerontological Evaluation Study.

Housing tenure is an important aspect to determine health. However, even though renters tend to have more socioeconomic disadvantages than homeowners, mortality risk between private and public renters compared with homeowners remains unclear. Japanese public rented housing, such as the Urban Renaissance Agency, has been developed for supplying an adequate living environment since 1950s. This study aimed to examine the mortality risk among older Japanese residents living in private and public rented houses compared with those living in owner-occupied houses using 9-year follow-up data. This study drew upon a 9-year follow-up of participants in the Japan Gerontological Evaluation Study, a population-based cohort study of Japanese independent adults aged ≥ 65 years. Mortality from 2010 to 2019 was analyzed for 44,007 respondents. Housing tenure was defined by a questionnaire. Cox regression models were used for calculating the hazard ratio for mortality. Bonferroni correction was used to account for multiple testing between rental houses. Overall, 10,638 deaths occurred during the follow-up period. Compared with housing owners, all rental housing groups had a significantly higher risk of mortality. Among renters, participants who lived in public rental housing had the lowest risk of mortality even after adjusting for sociodemographic characteristics, health status, social status, and environmental status. Multiple testing among renters with Bonferroni correction showed that public renters had 0.80 times (95% CI 0.72-0.89) lower mortality risk than private renters. Although Japanese older adults living in public rental housing had a higher mortality risk than homeowners, this risk was lower than that among private renters. A positive neighborhood environment based on well-planned urban development may have contributed to this result. The results suggest that planned urban development lowers the risk of mortality in older renters in Japan.

Social participation and functional disability trajectories in the last three years of life: The Japan Gerontological Evaluation Study.

BACKGROUND: Functional disability has various patterns from onset until death. Although social participation is a known protective factor against functional disability among older individuals, it is unclear whether social participation is associated with the trajectory patterns of functional disability prior to death. This study assessed the association between social participation, specifically in horizontal and vertical groups, and the trajectories of functional disability prior to death. METHODS: We used survey data from the 2010 Japan Gerontological Evaluation Study for functionally independent older adults combined with public long-term care insurance system data from 2010 to 2016 (n = 4,502). The outcome variables included five previously identified trajectory patterns using group-based trajectory modeling. As the explanatory variable, we used three definitions of social participation: any group, horizontal group (e.g., sports, hobbies), or vertical group (e.g., political, religious), at least once a month. We used a multinomial logistic regression analysis to calculate odds ratios with 95 % confidence intervals for the identified trajectory patterns. RESULTS: Participation in any groups was significantly less likely to belong to "Accelerated disability" (OR=0.74 [95 % CIs 0.60-0.92]), "Persistently mild disability" (0.68 [0.55-0.84]), and "Persistently severe disability" (0.67 [0.50-0.83]) compared to "Minimum disability." Although participation in horizontal groups was similarly associated with trajectories regardless of gender, vertical groups was not associated with trajectories among males. CONCLUSIONS: Social participation among older adults may be associated with an extended period of living without disabilities before death. This association may differ by gender and social participation group and requires further research.