Mapping the human gut mycobiome in middle-aged and elderly adults: multiomics insights and implications for host metabolic health

ObjectiveThe human gut fungal community, known as the mycobiome, plays a fundamental role in the gut ecosystem and health. Here we aimed to investigate the determinants and long-term stability of gut mycobiome among middle-aged and elderly adults. We further explored the interplay between gut fungi and bacteria on metabolic health.DesignThe present study included 1244 participants from the Guangzhou Nutrition and Health Study. We characterised the long-term stability and determinants of the human gut mycobiome, especially long-term habitual dietary consumption. The comprehensive multiomics analyses were performed to investigate the ecological links between gut bacteria, fungi and faecal metabolome. Finally, we examined whether the interaction between gut bacteria and fungi could modulate the metabolic risk.ResultsThe gut fungal composition was temporally stable and mainly determined by age, long-term habitual diet and host physiological states. Specifically, compared with middle-aged individuals, Blastobotrys and Agaricomycetes spp were depleted, while Malassezia was enriched in the elderly. Dairy consumption was positively associated with Saccharomyces but inversely associated with Candida. Notably, Saccharomycetales spp interacted with gut bacterial diversity to influence insulin resistance. Bidirectional mediation analyses indicated that bacterial function or faecal histidine might causally mediate an impact of Pichia on blood cholesterol.ConclusionWe depict the sociodemographic and dietary determinants of human gut mycobiome in middle-aged and elderly individuals, and further reveal that the gut mycobiome may be closely associated with the host metabolic health through regulating gut bacterial functions and metabolites.

Characteristics of Tip of the Tongue Phenomenon on the Task of Naming Celebrities in Healthy Elderly Adults

Objectives: In general, the incidence of Tip of the tongue (TOT) phenomenon increases with age, but studies on the difference in the incidence of TOT phenomenon according to the age of healthy elderly adults are limited. The purpose of this study was to investigate the incidence and resolution rate of the TOT, and to find out the change in performance according to the syllabic clues.Methods: Ninety-six healthy elderly people whose age range was between 65 and 84 years old participated in the study. Participants were divided into three groups: 55-64 years old, 65-74 years old, and 75-84 years old age range groups. The TOT task used 30 questions about celebrity naming organized by period and category.Results: First, there was a significant difference of the TOT rate by age group, and as the age increased, the TOT rate due to partial retrieval failure and total retrieval failure increased. Second, the rate of TOT response type that explained the celebrity’s occupation was the highest in all groups. Third, there were significant differences between groups in both the voluntary TOT resolution rate and the TOT resolution rate after providing the syllabic clue. The recovery rate after the syllabic clues decreased with increasing age.Conclusion: This study observed the difference in characteristics of TOT phenomenon in elderly adults according to age group and the importance of phonological clues in TOT phenomenon resolution.

The Association of Sleep Duration With Vision Impairment in Middle-Aged and Elderly Adults: Evidence From the China Health and Retirement Longitudinal Study

Objective: This study aims to investigate the association of sleep duration with vision impairment (VI) in middle-aged and elderly adults.Methods: This cross-sectional study used the data from the baseline survey of the China Health and Retirement Longitudinal Study (CHARLS) 2011–2012, a national survey of adults aged 45 years or older. Weighted multilevel logistic regression models were used to evaluate the association between self-reported sleep duration and VI.Results: Of the 13,959 survey respondents, a total of 4,776 (34.2%) reported VI. The prevalence of short (≤6 h/night) and long (>8 h/night) sleep durations was higher among respondents with VI than those without VI (P < 0.001). Multilevel logistic regression models showed that compared with a sleep duration of 6–8 h/night, a sleep duration of ≤6 h/night was associated with a 1.45-fold [95% confidence interval (CI) = 1.34–1.56] higher VI risk, and a sleep duration of >8 h/night was associated with a 1.18-fold (95% CI = 1.03–1.34) higher VI risk, after adjusting for sociodemographic data, lifestyle factors, and health conditions. Vision impairment was associated with short sleep duration in respondents from all age or gender categories. However, VI was associated with long sleep duration in respondents from the elderly or female categories. The association between VI and long sleep duration disappeared in respondents of middle-aged or male categories.Conclusions: The potential impact of sleep on the risk of visual functions requires further attention. A more comprehensive and integrated health care and rehabilitation system covering vision and sleep is also needed.

The Impact of Cycling Specialization on Successful Aging and the Mediating Role of Loneliness

Recent studies have provided some evidence supporting that cycling specialization (CS) may be positively related to successful aging (SA) among elderly adults. However, there is a gap regarding the examination of the role of loneliness in the relationship between CS and SA. A hypothetical model was proposed to test the relationship between CS, SA, and loneliness. For this purpose, this study randomly conducted a questionnaire survey among 395 cycling participants over the age of 60 in China. The results showed that behavior, cognition, and affect had negative effects on loneliness. Behavior, cognition, and affect were positively associated with SA. Loneliness was negatively related to SA. Furthermore, behavior, cognition, and affect had positive and indirect effects on SA through loneliness. These results offered some new insights for understanding the relationship between CS and SA, especially considering the indirect effect of loneliness. The limitations and implications of the findings were discussed.

Association between Benton Visual Retention Test scores and PET imaging in elderly adults

Background: The Benton Visual Retention Test (BVRT) is a well-validated and reliable test for assessing visual memory and visuospatial function. However, the association between the BVRT score and imaging biomarker of Alzheimer’s disease (AD) remains unclear. Objective: This study examined whether the BVRT score is associated with brain amyloid burden and cortical glucose metabolism in elderly adults without dementia. Methods: A total of 69 elderly adults without dementia, including 45 subjects with amnestic mild cognitive impairment and 24 cognitively healthy adults, underwent the BVRT and 11C-Pittsburgh compound B (PiB) and 18F-fluorodeoxyglucose (FDG) positron emission tomography. The correct scores in the BVRT were used for analyses. A multiple linear regression analysis was conducted to investigate the relationship between BVRT scores and PiB or FDG uptake. Moreover, a voxel-wise linear regression analysis of the association between BVRT scores and PiB or FDG uptake was conducted using Statistical Parametric Mapping. Results: After adjusting for age, sex, education, and ApoE4 status, the BVRT scores were inversely correlated with the mean PiB uptake (β = −0.35, P = 0.003), whereas they were positively correlated with FDG uptake (β = 0.266, P = 0.038). Moreover, the BVRT scores were inversely correlated with amyloid burden in the right superior temporal and superior frontal gyri and the left parietal lobe, whereas they were positively correlated with cortical glucose metabolism in the right posterior cingulate and milled temporal gyri, left temporoparietal lobe, and right superior frontal gyrus. Conclusion: BVRT scores are correlated with brain amyloid burden and cortical glucose metabolism, mainly in regions commonly affected in AD.