EFFECTS OF VARIOUS BIOMECHANICAL ERRORS ON COMPUTED JOINT KINETICS VALUES

Inverse dynamics analysis has been widely used to evaluate the joint kinetics during various human movements. Several investigators have reported that the joint kinetic computations could be considerably affected by diverse biomechanical errors. Kim et al (2007) clarified the influence of measurement errors of Center of Pressure (CoP) location of force platform on calculated three-dimensional (3D) lower limb joint moment during walking. However, it is not yet clear how biomechanical errors, such as errors in CoP, Body Segment Parameters (BSP) and Joint Center Location (JCL) data, affect the calculated joint kinetics values. The purpose of this study was to clarify the influences of the alterations of anthropometric, kinematic, and kinetic variables on the magnitude and time-series curve patterns of the 3D ankle joint moment during human running

Prevalence of Dementia and Mild Cognitive Impairment in the Rural Island Town of Ama-cho, Japan

Aims: In order to determine the prevalence of dementia and mild cognitive impairment (MCI), we conducted a population-based study in Japan. Methods: Participants included 924 subjects aged 65 years or older who resided in the town of Ama-cho. In phase 1 of the study, the Mini-Mental State Examination and Clinical Dementia Rating were administered for screening purposes. In phase 2 of the study, the subjects who screened positive were further examined by neurologists. Dementia and MCI were diagnosed by means of DSM-IV and International Working Group on MCI criteria, respectively. Results: By the prevalence date of June 1, 2010, 24 subjects had deceased or lived outside the town. In total, 723 of the remaining 900 subjects received a phase 1 test. In phase 2, 98 subjects were diagnosed with amnestic MCI, 113 subjects with non-amnestic MCI, and 82 subjects with dementia. Of the subjects who did not receive the phase 1 test, 66 subjects were diagnosed as having dementia according to data from their town medical card or the Long-term Care Insurance System. The crude prevalence of amnestic MCI, non-amnestic MCI, and dementia were 10.9, 12.6, and 16.4%, respectively. Conclusion: Consistent with the striking increase in the number of elderly individuals, we report higher prevalence of MCI and dementia in Japan than previously described

The effect of modifiable healthy practices on higher-level functional capacity decline among Japanese community dwellers

This study aimed to clarify the effects of the accumulation of 8 modifiable practices related to health, including smoking, alcohol drinking, physical activity, sleeping hours, body mass index, dietary diversity, ikigai (life worth living), and health checkup status, on higher-level functional capacity decline among Japanese community dwellers. Data were derived from the National Institute for Longevity Sciences - Longitudinal Study of Aging. Subjects comprised 1269 men and women aged 40 to 79 years at baseline (1997–2000) who participated in a follow-up postal survey (2013). Higher-level functional capacity was measured using the Tokyo Metropolitan Institute of Gerontology Index of Competence (total score and 3 subscales: instrumental self-maintenance, intellectual activity, and social role). The odds ratio (OR) and 95% confidence interval (CI) for a decline in higher-level functional capacity in the follow-up study according to the total number of healthy practices were analyzed using the lowest category as a reference. Multivariate adjusted ORs (95% CIs) for the total score of higher-level functional capacity, which declined according to the total number of healthy practices (0–4, 5–6, 7–8 groups) were 1.00 (reference), 0.63 (0.44–0.92), and 0.54 (0.31–0.94). For the score of social role decline, multivariate adjusted ORs (95% CIs) were 1.00 (reference), 0.62 (0.40–0.97), and 0.46 (0.23–0.90), respectively (P for trend = 0.04). Having more modifiable healthy practices, especially in social roles, may protect against a decline in higher-level functional capacity among middle-aged and elderly community dwellers in Japan

Smaller Hippocampal Volume and Degraded Peripheral Hearing Among Japanese Community Dwellers

A growing body of literature has demonstrated that dementia and hearing loss are interrelated. Recent interest in dementia research has expanded to brain imaging analyses with auditory function. The aim of this study was to investigate the link between hearing ability, which was assessed using pure-tone audiometry, and the volume of brain regions, specifically the hippocampus, entorhinal cortex, Heschl’s gyrus, and total gray matter, using Freesurfer software and T1-weighted brain magnetic resonance imaging. The data for 2082 samples (age range = 40–89 years) were extracted from a population-based cohort of community dwellers. Hearing-impaired individuals showed significantly smaller hippocampal volumes compared with their non-hearing-impaired counterparts for all auditory frequency ranges. In addition, a correlational analysis showed a significant dose-response relationship for hearing ability and hippocampal volume after adjusting for potential confounding factors so that the more degraded the peripheral hearing was, the smaller the hippocampal volume was. This association was consistent through the auditory frequency range. The volume of the entorhinal cortex, right Heschl’s gyrus and total gray matter did not correlate with hearing level at any frequency. The volume of the left Heschl’s gyrus showed a significant relationship with the hearing levels for some auditory frequencies. The current results suggested that the presence of hearing loss after middle age could be a modifier of hippocampal atrophy

No Appreciable Effect of Education on Aging-Associated Declines in Cognition: A 20-Year Follow-Up Study

Education has been claimed to reduce aging-associated declines in cognitive function. Given its societal relevance, considerable resources have been devoted to this research. However, because of the difficulty of detecting modest rates of change, findings have been mixed. These discrepancies may stem from methodological shortcomings such as short time spans, few waves, and small samples. The present study overcame these limitations (N = 1,892, nine waves over a period of 20 years). We tested the effect of education level on baseline performance (intercept) and the rate of change (slope) in crystallized and fluid cognitive abilities (gc and gf, respectively) in a sample of Japanese adults. Albeit positively related to both intercepts, education had no impact on either the gc or the gf slope. Furthermore, neither intercept exhibited any appreciable correlation with either slope. These results thus suggest that education has no substantial role (direct or mediated) in aging-related changes in cognition

The Associations Between Smoking Habits and Serum Triglyceride or Hemoglobin A1c Levels Differ According to Visceral Fat Accumulation

Background: Whether smokers and former smokers have worse lipid profiles or glucose levels than non-smokers remains unclear.Methods: The subjects were 1152 Japanese males aged 42 to 81 years. The subjects were divided according to their smoking habits (nonsmokers, former smokers, and current smokers) and their visceral fat area (VFA) (<100 cm2 and ≥100 cm2).Results: The serum triglyceride (TG) levels of 835 males were assessed. In the VFA ≥100 cm2 group, a significantly greater proportion of current smokers (47.3%) exhibited TG levels of ≥150 mg/dL compared with former smokers (36.4%) and non-smokers (18.8%). The difference in TG level distribution between former smokers and non-smokers was also significant. However, among the subjects with VFA of <100 cm2, the TG levels of the three smoking habit groups did not differ. The serum hemoglobin A1c (HbA1c) levels of 877 males were also assessed. In the VFA <100 cm2 group, significantly higher proportions of current smokers (17.9%) and former smokers (14.9%) demonstrated HbA1c levels of ≥5.6% compared with non-smokers (6.3%). In contrast, in the VFA ≥100 cm2 group, significantly fewer former smokers displayed HbA1c levels of ≥5.6% compared with non-smokers and current smokers. Furthermore, the interaction between smoking habits and VFA was associated with the subjects’ TG and HbA1c concentrations, and the associations of TG and HbA1c concentrations and smoking habits varied according to VFA.Conclusions: Both smoking habits and VFA exhibited associations with TG and HbA1c concentrations. The associations between smoking habits and these parameters differed according to VFA

食生活の多様性とうつ病および自殺の有病率との関連 ―26年間の国際比較研究―

Purpose: This study aimed to determine the associations of dietary diversity with depression and suicide rates by an ecological analysis using 26-years worldwide statistics.Methods: Average food supply and energy supply by country, excluding loss between production and household, were obtained from the Food and Agriculture Organization of the United Nations Statistics Division database (FAOSTAT). Dietary diversity scores were calculated from food group classifications. Age-standardized depression prevalence and suicide rates per 100,000 people by country were obtained from the Global Burden of Disease (GBD) 2017 database. The association between food diversity scores and depression prevalence and suicide rates was analyzed by a mixed effects model controlling for covariates in 137 countries with populations of 1 million or greater.Results: A significant negative association was found in the analysis of the relationship between dietary diversity and the prevalence of major depression in the model controlled for all covariates [β (se) = –225.6 (61.9), p < 0.001]. In addition, a significant negative association between dietary diversity and the suicide rate was also found in the model controlled for all covariates [β (se) = –3.08 (1.50), p < 0.05].Conclusion: Dietary diversity was significantly negatively associated with the rates of major depression and suicide. Diets rich in foods may reduce the prevalence of depression and suicide rate.【目的】本研究は、26年間の世界的な統計を用いた生態学的分析により、食生活の多様性とうつ病や自殺率との関連を明らかにすることを目的とした。【方法】生産と家庭間の喪失を除く国別平均食料供給量とエネルギー供給量を国連食糧農業機関統計局データベース（FAOSTAT）から入手した。食物群分類から食事多様性スコアを算出した。年齢標準化された国別の人口10万人当たりのうつ病有病率と自殺率は、Global Burden of Disease（GBD）2017データベースから取得した。人口100万人以上の137カ国を対象に、食品多様性スコアとうつ病有病率および自殺率との関連を、共変量を制御した混合効果モデルで解析した。【結果】食生活の多様性とうつ病の有病率との関係を分析したところ、すべての共変量を調整したモデルにおいて、有意な負の関連が認められた［β（se）＝－225.6（61.9）、p < 0.001］。さらに、食生活の多様性と自殺率との間の有意な負の関連も、すべての共変量を調整したモデルで認められた［β（se）= －3.08（1.50）、p < 0.05］。【結論】食生活の多様性は、うつ病および自殺の発生率と有意に負の関連があった。食物を豊富に含む食事は、うつ病や自殺を減少させる可能性がある

Hearing impairment risk and interaction of folate metabolism related gene polymorphisms in an aging study

<p>Abstract</p> <p>Background</p> <p>Recent investigations demonstrated many genetic contributions to the development of human age-related hearing impairment (ARHI), however, reports of factors associated with a reduction in the ARHI risk are rare. Folate metabolism is essential for cellular functioning. Despite the extensive investigations regarding the roles of folate metabolism related gene polymorphisms in the pathophysiology of complex diseases, such as cancer, cardio-cerebrovascular disease, and atherosclerosis, little is known about the association with ARHI. The aim of this study is to investigate the effects of the methionine synthase (MTR) A2756G and methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphisms on the risk of hearing impairment in middle-aged and elderly Japanese.</p> <p>Methods</p> <p>Data were collected from community-dwelling Japanese adults aged 40-84 years who participated in the Longitudinal Study of Aging biennially between 1997 and 2008. We analyzed cumulative data (5,167 samples in accumulated total) using generalized estimating equations.</p> <p>Results</p> <p>The MTHFR 677T allele was significantly associated with a reduced risk of hearing impairment only when the subjects were wild-type homozygotes for MTR A2756G. The per-T allele odds ratio of MTHFR for the risk of developing hearing impairment was 0.7609 (95% CI: 0.6178-0.9372) in the MTR AA genotype. In addition, a subgroup analysis demonstrated that the favorable effect of the MTHFR 677T allele on the risk of developing hearing impairment was independent of folate and homocysteine level, whereas plasma total homocysteine level was independently associated with an increased risk of developing hearing impairment. The interactive effect of gene polymorphisms associated with folate metabolism may modify the risk of developing hearing impairment after middle age. These results contribute to the elucidation of the causes of ARHI.</p> <p>Conclusions</p> <p>The present study has found that the MTHFR 677T allele has a favorable effect on a risk of hearing impairment in the middle-aged and elderly population, only when the individuals were wild-type homozygotes for MTR A2756G.</p