Publications by authors named "Shigeyuki Nakaji"

The beneficial effects of water-soluble dietary fiber on liver fat and fibrosis involve the gut microbiota; however, few epidemiological studies have investigated this association. This large-scale epidemiological study aimed to determine the effect of water-soluble dietary fiber intake on liver fat and fibrosis via gut microbiota for the general population. We divided low- and high-intake groups by median daily water-soluble dietary fiber intake and matched background factors by propensity score matching for sex and age.

View Article and Find Full Text PDF

Background And Aim: Identifying the factors contributing to the progression of metabolic dysfunction-associated steatotic liver disease (MASLD), a lifestyle-related disease, is crucial for preventing future liver-related deaths. This study aimed to epidemiologically investigate factors, including single-nucleotide polymorphisms (SNPs) associated with alanine aminotransferase (ALT) levels >30 U/L and potential risk factors for liver fibrosis, in a general population cohort of patients with MASLD.

Methods: Among 1059 participants in the health checkup project, 228 who were diagnosed with MASLD were analyzed.

View Article and Find Full Text PDF
Article Synopsis
  • A study investigated the relationship between hemoglobin levels and brain volume in a large group of elderly participants using MRI scans.
  • It involved 2153 participants, mainly aged around 69, and found that lower hemoglobin levels were linked to reduced total white matter volume, especially in younger individuals.
  • The study concluded that low hemoglobin levels can negatively impact white matter volume as people age, but didn't find significant effects on gray matter or hippocampal volumes.
View Article and Find Full Text PDF

The genetic architecture of white matter lesions (WMLs) in Asian populations has not been well-characterized. Here, we performed a genome-wide association study (GWAS) to identify loci associated with the WML volume. Brain MRI and DNA samples were collected from 9479 participants in the Japan Prospective Studies Collaboration for Aging and Dementia (JPSC-AD).

View Article and Find Full Text PDF

The association between visceral fat area (VFA) and locomotive syndrome (LS) has been extensively studied in the older population; however, the association between VFA and early-stage LS (stage 1 [LS1]) remains unclear. In this cross-sectional study, we investigated this association across different age groups. The study involved 1,236 (524 male and 712 female) participants (aged 20-85 years).

View Article and Find Full Text PDF

Objectives: This study examined the impact of the Center of Healthy Aging Program (CHAP) on the cognitive function and economic burden associated with dementia.

Methods: This observational study utilised Iwaki cohort data. We included participants with mini-mental state examination (MMSE) scores and categorised them into pre- and post-CHAP groups based on their year of entry into the cohort (before 2013 or after) (index year).

View Article and Find Full Text PDF

Many factors are associated with the development and progression of metabolic dysfunction-associated steatotic liver disease (MASLD); however, genetics and gut microbiota are representative factors. Recent studies have highlighted the link between host genes and the gut microbiota. Although there have been many studies on the separate effects of single nucleotide polymorphisms (SNPs) and gut bacteria on MASLD, few epidemiological studies have examined how SNPs and gut bacteria interact in the development and progression of MASLD.

View Article and Find Full Text PDF
Article Synopsis
  • - This study examined how the oral environment and psychological factors like stress affect sleep quality, particularly in relation to temporomandibular disorders (TMDs).
  • - Data from 1,032 participants were analyzed using multiple regression to explore connections between TMDs, stress, and sleep quality measured by the Pittsburgh Sleep Quality Index (PSQI).
  • - The results indicated a strong link between TMDs and stress as factors contributing to poor sleep quality, suggesting that mental stress may lead to both sleep issues and TMD symptoms.
View Article and Find Full Text PDF
Article Synopsis
  • This study examined how different Japanese dietary patterns affect metabolic dysfunction-associated steatotic liver disease (MASLD) and liver fibrosis in 727 adults.
  • Participants' diets were categorized into rice, vegetable, seafood, and sweet groups, revealing that those in the vegetable group had lower indicators of liver fibrosis compared to the rice group.
  • The research identified body mass index ≥ 25 kg/m and HOMA-IR ≥ 1.6 as risk factors for liver fibrosis, while a vegetable-based diet, high in α-tocopherol (an antioxidant), was associated with a lower risk of developing liver fibrosis.
View Article and Find Full Text PDF
Article Synopsis
  • * Higher levels of hemoglobin A (HbA) and glycated albumin (GA), along with lower insulin secretion (measured by HOMA-β), were linked to smaller hippocampal volumes.
  • * The results suggest that managing blood sugar levels and insulin can help prevent reductions in hippocampal size, which may be important for reducing the risk of dementia.
View Article and Find Full Text PDF

Introduction: Small fibre neuropathy (SFN) is an early manifestation of diabetic polyneuropathy. Although oxidative stress, inflammation and change of intestinal bacterial population are assumed to be their pathogenesis, the effects of dietary nutrition have not been evaluated. The relationship between dietary nutrition intake and pain sensation was evaluated in the Japanese population.

View Article and Find Full Text PDF

Purpose: Dairy foods are nutritional sources of calcium, phosphorus, protein, and other nutrients that improve bone health. However, the effects of dairy consumption on bone biomarkers in the Japanese population remain unclear. This study explored the association between dairy consumption and bone biomarkers in Japanese adults.

View Article and Find Full Text PDF

Small nerve fibres located in the epidermis sense pain. Dysfunction of these fibres decreases the pain threshold known as small fibre neuropathy. Diabetes mellitus is accompanied by metabolic changes other than glucose, synergistically eliciting small fibre neuropathy.

View Article and Find Full Text PDF

The association between the gut microbiota and muscle strength has garnered attention in the context of mitigating muscle decline. However, many study subjects have been individuals with existing illnesses or the elderly only. This study aims to elucidate the association between the gut microbiota and muscle strength indicators using grip strength/BMI in a large-scale study of community residents.

View Article and Find Full Text PDF

Background: This study evaluates cost reduction in participants of a health awareness program (the Center of Healthy Aging Program, CHAP) in a Japanese rural area, characterized by an annual check-up and personalized interview on health issues and related risks immediately after the check-up.

Methods: This is a cross-sectional study using medical and caregiving costs and Japan-specific health check-up results in Hirosaki residents stored by the local government, which were individually-based linked to the CHAP information collected by Hirosaki University. This is the first study that used anonymized data with individually-based linkages to both a research institute and a local government in Japan under a strict limitation regarding linking to third-party data.

View Article and Find Full Text PDF
Article Synopsis
  • - The Japanese diet is considered healthy and its benefits may stem from the influence it has on oral and gut microbiota, which play a crucial role in health.
  • - A study used a modified Japanese Diet Index (mJDI12) to analyze its association with microbiota in a rural Japanese population, selecting 396 participants based on their dietary habits.
  • - Findings indicated that those with a high mJDI12 had increased levels of beneficial butyric acid-producing bacteria and higher fiber intake, suggesting a positive impact of the Japanese diet on gut microbiota, although some oral microbiota was negatively affected.
View Article and Find Full Text PDF
Article Synopsis
  • The study investigates the relationship between liver fibrosis and reactive oxygen species (ROS) levels produced by neutrophils, focusing on how this varies with age and sex in the general population.
  • It involved 1,000 participants categorized into four groups based on sex and age, using various indices to assess liver fibrosis.
  • Findings indicated positive correlations between liver fibrosis scores and basal ROS levels in younger participants, while in females, higher liver fibrosis scores were associated with lower stimulated ROS levels, suggesting that enhancing neutrophil function could help prevent liver-related diseases.
View Article and Find Full Text PDF

Telomeres, repeated TTAGGG sequences at chromosomal ends, shorten with age and indicate cellular lifespan. Zinc can protect against telomere damage through its anti-oxidative effect. Meanwhile, telomere shortening was correlated with metabolic diseases of hypertension and type 2 diabetes.

View Article and Find Full Text PDF
Article Synopsis
  • Depression is a major global health issue, and its link to gut microbiota has been under-researched, especially in the Japanese population.
  • The study analyzed health data from Iwaki between 2017 and 2019, focusing on 37 gut microbiota genera and their relationship with depression levels measured by a specific depression scale.
  • Nine genera showed significant statistical relevance, with some linked to butyrate production, suggesting that gut bacteria may play a role in influencing depression through this process.
View Article and Find Full Text PDF

Reportedly, a relationship exists between intestinal microflora and obesity-related lifestyle diseases. spp. a major intestinal microbiota, accounts for 3-11% of human intestinal microflora.

View Article and Find Full Text PDF
Article Synopsis
  • * After matching participants based on various health factors, researchers found significant differences in gut microbiota diversity between those with and without liver fibrosis, but no notable differences in oral microbiota.
  • * The results suggest that gut microbiota may play a more significant role in liver fibrosis than oral microbiota, although certain strains didn't independently influence liver fibrosis when adjusting for other health variables.
View Article and Find Full Text PDF

Background: Enlarged perivascular spaces (EPVS) of the brain may be involved in dementia, such as Alzheimer's disease and cerebral small vessel disease (CSVD). Hypertension has been reported to be a risk factor for dementia and CSVD, but the association between blood pressure (BP) and perivascular spaces is still unclear. The aim of this study was to determine the association between BP and EPVS volumes and to examine the interactions of relevant factors.

View Article and Find Full Text PDF
Article Synopsis
  • Decreased gait speed in older adults is linked to higher prevalence of mild cognitive impairment (MCI), but the relationships differ by gender and age.
  • A study of over 8,200 Japanese participants aged 65 and older revealed that males consistently showed higher MCI prevalence than females, and the odds of MCI increased with slower gait speeds.
  • The findings indicate that while gait speed is a potential screening tool for MCI, its implications may vary based on age and gender, emphasizing the need for tailored approaches in clinical assessments.
View Article and Find Full Text PDF
Article Synopsis
  • Social isolation, defined as low frequency of social contact, has been linked to increased risks of dementia and depressive symptoms, prompting researchers to explore its potential effects on brain volume and health in older adults.
  • A study involving 8,896 dementia-free Japanese individuals aged 65 and older utilized brain MRI scans and health examinations to evaluate the relationship between frequency of social contact and various brain region volumes.
  • Results indicated that individuals with less social contact had significantly lower total brain volume and increased white matter lesions, suggesting that social interaction may play a critical role in brain health and that depressive symptoms could mediate this relationship.
View Article and Find Full Text PDF