Cohort Profile: The Rugao Longevity and Ageing Study (RuLAS)

Gut microbial features and circulating metabolomic signatures of frailty in older adults

Frailty, a multidimensional indicator of suboptimal aging, reflects cumulative declines across multiple physiological systems. Although age-related changes have been reported in gut microbiota, their role in healthy aging remains unclear. In this study, we calculated frailty index (FI) from 33 health-related items to reflect the overall health status of 1,821 older adults (62-96 years, 55% female) and conducted multi-omics analysis using gut metagenomic sequencing data and plasma metabolomic data. We identified 18 microbial species and 17 metabolites shifted along with frailty severity, with stronger links observed in females. The associations of nine species, including various Clostridium species and Faecalibacterium prausnitzii, with FI were reproducible in two external populations. Plasma glycerol levels, white blood cell count and kidney function partially mediated these associations. A composite microbial score derived from FI significantly predicted 2-year mortality (adjusted hazard ratio across extreme quartiles, 2.86; 95% confidence interval, 1.38-5.93), highlighting the potential of microbiota-based strategies for risk stratification in older adults.

Association between Perceived Stress and Motoric Cognitive Risk Syndrome in an Elderly Population: Rugao Longevity and Aging Study

INTRODUCTION

Previous studies have indicated a correlation between perceived stress and cognitive decline. However, it remains unknown whether high levels of perceived stress can result in motoric cognitive risk (MCR) syndrome. This study investigated the relationship between perceived stress and MCR in a community-based population.

METHODS

The study cohort comprised 852 elderly individuals from the Rugao Longitudinal Aging Cohort. Perceived stress was assessed using the 10-item Perceived Stress Scale (PSS-10), while MCR was defined as the coexistence of subjective memory complaints (SMCs) and slow gait speed.

RESULTS

The average age of the study participants is 79.84 ± 4.34 years. The mean score of PSS-10 among participants is 10.32 (range = 0-33; [SD] = 5.71), with a median score of 10.00 (6.00, 14.00). The prevalence of MCR is 9.3%. In the logistic regression analysis, for each 1-SD (5.71) increase in the global PSS-10 score, the risk of MCR increased by 40% (95% CI 1.09-1.80). Additionally, in the aspect of two components of MCR, with a 1-SD increase (5.71) in the global PSS-10 score, there was a 50% (95% CI 1.29-1.75) increase in the risk of SMCs and a 27% (95% CI 1.04-1.55) increase in the risk of slow gait speed. In terms of specific walking speed, there was a reverse correlation between the global PSS-10 score and walking speed (r = -0.14, p < 0.001).

CONCLUSIONS

This study provided preliminary evidence that high levels of perceived stress were associated with the risk of MCR in a community-dwelling population.

Intrinsic capacity and 5-year late-life functional ability trajectories of Chinese older population using ICOPE tool: the Rugao Longevity and Ageing Study

BACKGROUND AND AIMS

Knowledge of how intrinsic capacity (IC) shape functional ability (FA) trajectories in later life remains unclear. We investigated the changes in IC and their impact on 5-years FA trajectories in the Chinese older population.

METHODS

A total of 1640 older adults from the Rugao Longitudinal Ageing Study were included and analyzed. FA was assessed by The Lawton Instrumental Activities of Daily Living Scale (IADLs). We used cognition, psychology, locomotion, sensory capacity, and vitality to capture the multiple domains of IC according to the ICOPE method. The IC was derived retrospectively from variables collected before this was described by WHO.

RESULTS

At baseline, a higher IC was associated with higher IADLs (β = 0.98, 95% CI 0.90, 1.06, P < 0.001). Individuals with declines in IC between wave1 and wave2 experienced a faster decline in IADLs over time (β = - 0.28, 95% CI - 0.40, - 0.16, P < 0.001) after considering covariates. One or more impairment IC scores at baseline strongly predicted death (HR = 1.20, 95% CI 1.11, 1.30, P < 0.001). In addition, according to the IC scores at baseline, we stratify IC in low, middle, and high, compared with those in the high IC score, those in the low were associated with a 2.56-fold (95% CI 1.64, 4.01, P < 0.001) higher risk of mortality, after adjustment for variables.

CONCLUSION

Changes in IC shape FA trajectories. IC impairment is associated with an increased risk of death. Assessing intrinsic capacity would facilitate early identification of older adults at high risk of adverse outcomes and prompt targeted interventions.

Glomerular filtration rate by different measures and albuminuria are associated with risk of frailty: the Rugao Longitudinal Ageing Study

BACKGROUND AND AIM

A decreased estimated glomerular filtration rate (eGFR) is associated with frailty, but the association between kidney function and frailty using multidimensional assessments has not been entirely examined. We aimed to investigate whether albuminuria and the eGFR using different biomarkers were associated with frailty.

METHODS

A total of 1830 older adults were included. Kidney function was assessed by the eGFR (based on combined creatinine-cystatin C [eGFR_cr-cys]) and β₂-microglobulin [eGFR_B2M]) and urine albumin-creatinine ratio (UACR). Frailty was measured by the Fried phenotype (FP) and frailty index (FI). Logistic regression models were used to investigate cross-sectional and longitudinal associations of baseline kidney measures with prevalent and incident frailty.

RESULTS

At baseline, kidney function was associated with prevalent frailty. During the 2-year follow-up, a decreased eGFR (per 10 units) was associated with an increased risk of incident frailty using the FP (eGFR_cr-cys: OR 1.18, 95% CI 1.03-1.35; eGFR_B2M: OR 1.14, 95% CI 1.02-1.29, respectively) and FI (eGFR_B2M: OR 1.18, 95% CI 1.04-1.65). An increased logUACR was associated with a higher risk of incident frailty using the FP (OR 1.18, 95% CI 1.03-1.35). Additionally, individuals with chronic kidney disease (CKD) had a higher risk of incident frailty using the FP (eGFR_cr-cys: OR 2.13, 95% CI 1.28-3.47; eGFR_B2M: OR 1.58, 95% CI 1.10-2.29, respectively) and FI (eGFR_cr-cys: OR 1.97, 95% CI 1.15-3.32; eGFR_B2M: OR 1.51, 95% CI 1.03-2.24, respectively).

CONCLUSION

Kidney function decline and CKD were associated with an increased risk of prevalent and incident frailty in older adults. Physicians should pay more attention to monitoring frailty status in older adults with CKD, even in those with kidney function decline.

Effects of Variability in Glycemic Indices on Longevity in Chinese Centenarians

Background

Large fluctuations in blood glucose levels greatly impact the health and life span of elderly individuals. This study describes the characteristics of variability in glycemic indices in centenarians with the aim of emphasizing the importance of glycemic variability in elderly people.

Methods

We recruited individuals from Rugao City, Jiangsu Province, China from April 2020 to May 2021. The study cohort included 60 centenarians and 60 first-generation offspring, as well as 20 randomly selected non-cohabitant control individuals aged 60–80 years. A FreeStyle Libre H (hospital version) continuous glucose monitoring (CGM) device (Abbott Ireland UK) was used to measure glycemic variability. The indices measured included the time in target glucose range (TIR), time below target glucose range (TBR), time above target glucose range (TAR), mean amplitude of glycemic excursions (MAGE), mean of daily differences (MODD), coefficient of variation (CV), standard deviation of blood glucose (SDBG), continuous overlapping net glycemic action (CONGA), glucose management indicator (GMI) and estimated glycated hemoglobin (eHbA1c). Logistic regression was used to analyze the association between glycemic variability and longevity.

Results

Mean blood glucose (MBG), eHbA1c, GMI, mean fasting plasma glucose (M-FPG) and CONGA were lower in the centenarian group (p all < 0.05). PPGE-2 was higher in the control group than that measured in the centenarian and first-generation offspring groups (p < 0.05). There were no differences between the groups in MAGE, MODD, MAG, or TIR (p > 0.05). The risk of not achieving longevity increased with each one unit increase in MBG by 126% [2.26 (1.05–4.91)], eHbA1c by 67% [1.67 (1.03–2.72)], GMI by 568% [6.68 (1.11–40.30)], M-FPG by 365% [4.65 (1.57–13.75)], M-PPG1h by 98% [1.98 (1.18–3.31)], CONGA1 by 102% [2.02 (1.01–4.06)], Li by 200% [3.00 (1.04–8.61)], and PPGE-2 by 150% [2.50 (1.39–4.50)]. However, the risk of achieving longevity decreased with each unit increase of LBGI by 53% [0.47 (0.28–0.80)], ADRR by 60% [0.40 (0.18–0.86)], and TBR by 11% [0.89 (0.80–0.98)].

Conclusion

Fluctuation in blood glucose levels in centenarians is relatively small. Maintaining an average blood glucose level and keeping blood glucose fluctuations in the normal range is conducive to longevity.

Plasma homocysteine and macular thickness in older adults-the Rugao Longevity and Aging Study

OBJECTIVES

To determine the association of plasma homocysteine levels with retinal layer thickness in a large community cohort of older adults.

METHODS

The Rugao Longevity and Ageing Study is an observational, prospective and community-based cohort study. A total of 989 older adults who underwent spectral-domain optical coherence tomography (SD-OCT) were included and analyzed. Foveal, macular retinal nerve fibre layer (mRNFL) and ganglion cell layer plus inner plexiform layer (GC-IPL) thicknesses were measured by SD-OCT. Plasma homocysteine levels were measured using chemiluminescence immunoassay. Linear regression analyses were performed to evaluate the relationship between plasma homocysteine and retinal layer thickness while controlling for confounding factors.

RESULTS

Of the 989 participants, 500 (50.56%) were men. The mean age was 78.26 (4.58) years, and the mean plasma homocysteine level was 16.38 (8.05) μmol/L. In multivariable analyses, each unit increase in plasma homocysteine was associated with an 8.84 × 10^-2 (95% CI: -16.54 × 10^-2 to -1.15 × 10^-2, p = 0.032) μm decrease in the average inner thickness of the GC-IPL after controlling for confounding factors. The association remained significant even in participants without major cardiovascular disease or diabetes (β = -10.33 × 10^-2, 95% CI: -18.49 × 10^-2 to -2.18 × 10^-2, p = 0.013). No significant associations of plasma homocysteine levels with macular thickness or mRNFL were found in primary and sensitivity analyses (p > 0.05).

CONCLUSIONS

Increased plasma homocysteine levels are associated with a thinner GC-IPL. Plasma homocysteine may be a risk factor for thinner retinas in older adults.

Plasma folate levels in relation to cognitive impairment: a community-based cohort of older adults in China

PURPOSE

Lower plasma level of folate has been associated with an increased risk of age-related cognitive impairment. However, studies that examined this relation have yielded mixed results. We aimed to examine the prospective association of plasma folate level with risk of cognitive impairment in a community-based prospective cohort of older adults in China.

METHODS

This study included 615 participants (mean age: 76.3 years) without baseline cognitive impairment from the Rugao Longevity and Ageing Study (RuLAS). We used logistic regression to examine the prospective association between baseline plasma folate and risk of cognitive impairment in the next two years. Fasting blood samples were collected and assayed for plasma folate level at baseline. Cognitive impairment was defined as Hasegawa Dementia Scale (HDS) score ≤ 21.5 points.

RESULTS

During two years' follow-up, 20.7% of the participants developed cognitive impairment. After controlled for age, gender, and plasma homocysteine, a higher level of plasma folate was associated with lower odds of cognitive impairment. The corresponding odds ratio (OR) with 95% confidence interval was 0.41 (0.19-0.89) comparing participants at extreme quintiles of plasma folate (median level 17.2 vs. 6.3 nmol/L). The associations were similar after further adjustment for major demographic and lifestyle factors (OR = 0.42, 0.18-0.98). Moreover, the inverse association was particularly stronger among males (OR = 0.12, 0.03-0.52) but was non-significant among females.

CONCLUSION

Our findings support a potential beneficial role of higher plasma folate levels in cognitive function in older Chinese adults, particularly among males. Future studies with larger sample size and longer follow-up are warranted to confirm these findings and to identify the optimal plasma folate level for cognitive function.

Development and Validation of a New Simple Functional Score in the Older Chinese Population

Background

Existing aging metrics incorporating cognitive and physical function are often not feasible for application in research and clinical practice. Therefore, this study aimed to develop and validate a new simple functional score based on self-reported cognitive and physical function in the older Chinese population.

Methods

The development sample included 3,929 older adults aged 60–95 years from the China Health and Retirement Longitudinal Study (CHARLS). The validation sample included 1,345 older adults aged 60–87 years from the Rugao Longitudinal Aging study (RLAS). Logistic regression models and receiver operating characteristic curves were used to examine the associations of the new functional score with all-cause mortality risk.

Results

Six items were selected to construct the new functional score in CHARLS. This functional score was associated with all-cause mortality risk, with an adjusted odds ratio of 1.10 (95% confidence interval = 1.07, 1.13). This functional score presented additional predictive utility beyond age and sex, as demonstrated by the significantly increased C-statistic, integrated discrimination improvement (IDI), and continuous net reclassification improvement (NRI) (all P < 0.001). Furthermore, this functional score was further validated in RLAS, such that adding the new functional score to a model of age and sex improved all-cause mortality risk discrimination (IDI = 0.036, P < 0.001; NRI = 0.485, P < 0.001). To facilitate the quick screening of the older population with deteriorations in cognitive and physical function, we introduced a publicly available online tool designed for this new functional score.

Conclusions

A new functional score based on six self-reported items was developed and validated in the older Chinese population, and was demonstrated to be a simple and practical tool to assess functional deterioration, showing good feasibility, and performance.

BMI, Blood Pressure, and Plasma Lipids among Centenarians and Their Offspring

Background

The burden of cardiovascular diseases (CVDs) is increasing substantially due to population growth and aging. Determining effective prevention and understanding the underlying mechanisms remain desirable pursuits for increasing the quality of life. As centenarians and their offspring may have genetic advantages, they may present with healthier cardiovascular-related profiles.

Methods

We launched a cross-sectional household-based survey of centenarian families, including 253 centenarians, 217 centenarian offspring, and 116 offspring spouses without centenarian parents from county-level Chinese longevity city Rugao. Among offspring and offspring spouses were the following arrangements: 101 paired offspring and offspring spouses who lived together, 116 unpaired offspring, and 16 unpaired spouses. We investigated their cardiovascular-related health status including waist circumference, body mass index (BMI), blood pressure, and plasma lipids and compared results among centenarians, centenarian offspring, and offspring spouses.

Results

Centenarians ranged from 99 to 109 years with a median age of 100 years. Centenarian offspring, with a median age of 70 years, and offspring spouses, with a median age of 69 years, shared similar age. Results of blood pressure, plasma lipid levels, and BMI displayed no significant difference between centenarian offspring and offspring spouses. However, centenarians appeared to have lower waist circumference, BMI, TC, LDL-C, TG, and diastolic blood pressure but higher levels of systolic blood pressure (p < 0.05). Multivariate analysis showed the prevalence of obesity, hypertension, and dyslipidemia was similar between centenarian offspring and offspring spouses, while centenarians appeared to have a lower prevalence of obesity and a higher prevalence of hypertension (p < 0.05).

Conclusions

Centenarians and centenarian offspring did not present healthier BMI, blood pressure, or plasma lipids than offspring spouses. Further research on longevity and cardiovascular diseases are desirable.

Association of immunity markers with the risk of incident frailty: the Rugao longitudinal aging study

BACKGROUND

The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and systemic immune-inflammation index (SII) are readily available circulatory immunity markers that are associated with components of frailty. However, few studies have investigated the relationship between these immunity markers and frailty, and it remains unknown whether they are predictive of incident frailty in older adults in general. Hence, we aimed to examine the association of these immunity markers with the risk of incident frailty.

RESULTS

Overall, 1822 older adults (mean age was 78.03 ± 4.46 years) were included in the Rugao Longitudinal Aging Study. NLR, PLR and SII were calculated from blood cell counts. The frailty definition was based on the Fried phenotype. At baseline, 200 (10.98%) individuals were defined as frailty, and no significant associations of NLR, PLR and SII with frailty were found. During the 2-year follow-up, 180 (15.67%) individuals were new-onset frailty. After adjustment, an increased logNLR (odds ratio [OR] 2.92, 95% confidence interval [CI] 1.20-7.18), logPLR (OR 2.54, 95% CI: 1.01-6.53) and logSII (OR 2.34, 95% CI: 1.16-4.78) were significantly associated with a higher risk of incident frailty in all individuals. Additionally, the associations of logNLR (OR 4.21, 95% CI 1.54-11.62 logPLR (OR 3.38, 95% CI: 1.17-9.91) and logSII (OR 2.56, 95% CI: 1.15-5.72) with incident frailty were remained after excluding individuals with comorbidities. In further analyzed, individuals with higher levels of NLR and SII had higher risk of incident frailty when we stratified individuals by quartiles of these immunity markers.

CONCLUSION

NLR and SII are easily obtained immunity markers that could be used to predict incident frailty in clinical practice.

Phenotype correlations reveal the relationships of physiological systems underlying human ageing

Ageing is characterized by degeneration and loss of function across multiple physiological systems. To study the mechanisms and consequences of ageing, several metrics have been proposed in a hierarchical model, including biological, phenotypic and functional ageing. In particular, phenotypic ageing and interconnected changes in multiple physiological systems occur in all ageing individuals over time. Recently, phenotypic age, a new ageing measure, was proposed to capture morbidity and mortality risk across diverse subpopulations in US cohort studies. Although phenotypic age has been widely used, it may overlook the complex relationships among phenotypic biomarkers. Considering the correlation structure of these phenotypic biomarkers, we proposed a composite phenotype analysis (CPA) strategy to analyse 71 biomarkers from 2074 individuals in the Rugao Longitudinal Ageing Study. CPA grouped these biomarkers into 18 composite phenotypes according to their internal correlation, and these composite phenotypes were mostly consistent with prior findings. In addition, compared with prior findings, this strategy exhibited some different yet important implications. For example, the indicators of kidney and cardiovascular functions were tightly connected, implying internal interactions. The composite phenotypes were further verified through associations with functional metrics of ageing, including disability, depression, cognitive function and frailty. Compared to age alone, these composite phenotypes had better predictive performances for functional metrics of ageing. In summary, CPA could reveal the hidden relationships of physiological systems and identify the links between physiological systems and functional ageing metrics, thereby providing novel insights into potential mechanisms underlying human ageing.

Cognitive frailty predicting death and disability in Chinese elderly

OBJECTIVE

Cognitive frailty (CF) is associated with adverse health outcomes, but different CF models have been proposed in the literature. We explored whether cognitive impairment (CoI) assessed by the Revised Hasegawa dementia scale (HDS-R) and physical frailty (PF) assessed by the modified Frailty Phenotype can be combined to predict risks of adverse outcomes in elderly Chinese subjects.

METHODS

The data collected in the Rugao Longevity and Aging Study were used. PF was assessed by the modified Frailty phenotype. CoI was defined as the lowest 20% of the HDS-R score. CF was defined as the co-existence of physical frailty and CoI, excluding those with severe CoI(HDR-S ≤ 10). The date and cause of death were acquired from the Death registry of Rugao's Civil Affairs Bureau. Disability was measured using the activities of daily living (ADL) scale.

RESULTS

The prevalence of CF was 2.9% at baseline. During 3-year follow-up, 130 (8.1%) of the 1607 elderly subjects died. The highest mortality risk was observed among subjects with CF (hazard ratio [HR] = 2.94, 95% confidence interval [CI] = 1.28-6.78). Fully adjusted survival plots showed that CF was associated with the highest risk for 3-year mortality. The incidence of ADL disability was 6.0% after 3 years. Compared with the robust and non-CoI elderly, CF was associated with a 10.48-fold (95% CI 2.98-36.80) higher risk of ADL disability.

CONCLUSIONS

The CF model defined as a combination of HDS-R and Frail Phenotypes showed predictive validity for all-cause death and new-onset ADL disability 3 years later.

Prevalence, Causes, and Factors Associated with Visual Impairment in a Chinese Elderly Population: The Rugao Longevity and Aging Study

Purpose

This study aimed to explore the current prevalence, causes, and factors associated with visual impairment in a Chinese elderly population.

Methods

A random sample of 2164 candidates aged ≥70 years was selected. Among them, 1914 participants (response rate: 88.4%) underwent comprehensive eye examinations. The prevalence and causes of visual impairment were estimated, and the associated factors were identified.

Results

The standardized prevalence of mild visual impairment (<6/12 to ≥6/18), moderate to severe visual impairment (MSVI) (<6/18 to ≥3/60), and blindness (<3/60) in the better eye were 20.5%, 25.8%, and 3.4%, respectively. The leading cause of visual impairment was cataract (49.7%), followed by uncorrected refractive error (26.5%), myopic maculopathy (5.8%), and posterior capsular opacification (5.5%). Optical coherence tomography revealed that vitreoretinal interface abnormalities were the third most common cause of monocular mild visual impairment (2.2%) and MSVI (4.4%) in the elderly population. A large number of patients with visual impairment (81.7%) were amenable to undergo the interventions. Visual impairment was associated with advanced age (odds ratio [OR], 1.09 per year; p<0.001), female sex (OR, 1.59; p=0.003), self-reported visual impairment (OR, 1.91; p<0.001), cognitive impairment (OR, 1.40, p=0.005), and high educational level (OR, 0.75; primary, p=0.045; and OR, 0.53, secondary or higher; p<0.001).

Conclusion

Visual impairment was common in the Chinese elderly population and a severe health and social problem. Practicable policies are urgently needed to popularize eye health knowledge and promote treatments for visual impairment in elderly people in rural China.

The Modified Healthy Ageing Index Is Associated with Mortality and Disability: The Rugao Longevity and Ageing Study

INTRODUCTION

The Healthy Ageing Index (HAI) has been shown not only to have wider applicability and predictive ability but also to adequately predict mortality in Western populations. There is still a lack of studies validating the applicability of the HAI in China.

OBJECTIVE

To evaluate the applicability of the HAI and validate whether the HAI is suitable for monitoring ageing in the elderly population in China.

METHODS

Data were obtained from the Rugao Longevity and Ageing Study. The modified HAI was constructed based on systolic blood pressure, chronic pulmonary diseases, cognitive function, fasting glucose, and kidney function. It was calculated in 1719 individuals aged 70-84 years at baseline. The adverse outcomes were mortality and disability. Demographic, physiologic, and clinical data were collected. Cox proportional hazards and logistic regression models were used to analyze the relationship between the modified HAI and adverse outcomes.

RESULTS

A total of 1,719 older adults were analyzed in our study. A total of 793 (46.13%) males were recruited. The mean age was 75.69 ± 3.93 years. At the 5-year follow-up, there were 266 deaths and 275 individuals with disabilities. In the multivariable models, the modified HAI was associated with mortality (hazard ratio = 1.11, 95% confidence interval [CI]: 1.03-1.20) and disability (odds ratio = 1.11, 95% CI: 1.05-1.18). In the sensitivity analyses, similar associations remained after imputing missing data using multiple imputation and excluding participants with major cardiovascular disease at baseline.

CONCLUSION

The modified HAI was a robust and independent predictor of adverse outcomes. It is a valid and feasible tool for monitoring ageing in older adults.

The Reciprocal Relationship between Frailty and Depressive Symptoms among Older Adults in Rural China: A Cross-Lag Analysis

(1) Objective: This study aimed to investigate the reciprocal relationship between frailty and depressive symptoms using longitudinal data among older adults in China. (2) Methods: Data derived from 2014 and 2017 waves of a longitudinal study of 1367 older adults aged 70–84 years, living in rural areas of Jiangsu Province, China. Cross-lagged panel model and a multiple group model were used to examine the temporal effect of frailty on depressive symptoms and vice versa. (3) Results: Frailty was associated with subsequent increase in depressive symptoms, such that participants with higher levels of frailty increase the risks of depressive symptoms (b = 0.090, p < 0.01). Depressive symptoms were significant predictors of increased frailty (b = −0.262, p <0.001). However, older men and older women had no significant differences in the reciprocal relationship between frailty and depressive symptoms. (4) Conclusions: In conclusion, we find a significant bi-directional relationship between frailty and depressive symptoms. This finding confirms the dyadic model of frailty and depression. Implications for interventions and policy to help frail and depressive older adults are discussed.

Sleep Disturbances Are Associated With Depressive Symptoms in a Chinese Population: The Rugao Longevity and Aging Cohort

Objective: To investigate the cross-sectional and longitudinal relationships between sleep disturbances and depressive symptoms in older Chinese adults. Methods: This study included baseline and 3.5-year follow-up data of 1,631 Chinese men and women aged 70 years or older from the aging arm of the Rugao Longevity and Aging Study. Depressive symptoms were assessed by the 15-item Geriatric Depression Scale (GDS). Sleep disturbances were assessed by using the Pittsburgh Sleep Quality Index (PSQI). Logistic regression models were used to estimate the odds ratios (ORs) of the associations. Results: In the cross-sectional analysis, individuals with greater total PSQI scores exhibited significantly higher risk of "depressive symptoms" (OR: 1.31, 95% CI: 1.21-1.41) and "some depressive symptoms" (OR: 1.22, 95% CI: 1.17-1.28). Specifically, higher scores on the sleep efficiency PSQI subscale were associated with greater odds for "depressive symptoms" (OR: 1.54, 95% CI: 1.30-1.84) and "some depressive symptoms" (OR: 1.42, 95% CI: 1.29-1.57). Our longitudinal analyses indicated an association between greater PSQI total scores at baseline and greater odds of having "some depressive symptoms" at follow-up (OR: 1.07, 95% CI: 1.00-1.14). Additionally, higher scores on the sleep efficiency PSQI subscale had an association with higher odds for "some depressive symptoms" (OR: 1.21, 95% CI: 1.04-1.41). Conclusions: Poor self-reported global sleep quality and sleep efficiency PSQI subscale scores were associated with levels of depressive symptoms in an older Chinese population, indicating that global sleep quality and sleep efficiency may be risk factors for depression and can possibly predict the levels of depressive symptoms.

Mitochondrial DNA Haplogroup M7 Confers Disability in a Chinese Aging Population

Mitochondrial DNA (mtDNA) haplogroups have been associated with functional impairments (i.e., decreased gait speed and grip strength, frailty), which are risk factors of disability. However, the association between mtDNA haplogroups and ADL disability is still unclear. In this study, we conducted an investigation of 25 mtSNPs defining 17 major mtDNA haplogroups for ADL disability in an aging Chinese population. We found that mtDNA haplogroup M7 was associated with an increased risk of disability (OR = 3.18 [95% CI = 1.29-7.83], P = 0.012). The survival rate of the M7 haplogroup group (6.1%) was lower than that of the non-M7 haplogroup group (9.5%) after a 6-year follow-up. In cellular studies, cytoplasmic hybrid (cybrid) cells with the M7 haplogroup showed distinct mitochondrial functions from the M8 haplogroup. Specifically, the respiratory chain complex capacity was significantly lower in M7 haplogroup cybrids than in M8 haplogroup cybrids. Furthermore, an obvious decreased mitochondrial membrane potential and 40% reduced ATP-linked oxygen consumption were found in M7 haplogroup cybrids compared to M8 haplogroup cybrids. Notably, M7 haplogroup cybrids generated more reactive oxygen species (ROS) than M8 haplogroup cybrids. Therefore, the M7 haplogroup may contribute to the risk of disability via altering mitochondrial function to some extent, leading to decreased oxygen consumption, but increased ROS production, which may activate mitochondrial retrograde signaling pathways to impair cellular and tissue function.

Frailty index is associated with increased risk of elevated BNP in an elderly population: the Rugao Longevity and Ageing Study

BACKGROUND AND AIMS

To explore whether frailty, defined by frailty index (FI), is associated with the risk of elevated B-type natriuretic peptide (BNP), a surrogate endpoint of cardiovascular events.

METHODS

Data of 1382 community-dwelling elders who had no documented cardiovascular diseases aged 70-84 years from the ageing arm of the Rugao Longevity and Ageing Study was used. Traditional risk factor index (TI) was constructed using eight established cardiovascular-related risk factors. FI was constructed using 36 health deficits. Elevated BNP was defined as BNP ≥ 100pg/mL. Cardiovascular events include incident major cardiovascular events and cardiovascular death.

RESULTS

During a 3-year follow-up period, 97 participants had cardiovascular events. TI was not associated with the risk of elevated BNP, but was associated with cardiovascular events (HR = 1.16, 95% CI 1.01-1.34). Frailty index was not only associated with cardiovascular events (HR = 1.32, 95% CI 1.06-1.64), but also associated with elevated BNP with an OR of 1.22 (95% CI 1.02-1.47) for each 0.1 increment. Further, both frailty (OR = 1.93, 95% CI 1.67-3.17) and pre-frailty (OR = 1.54, 95% CI 1.06-2.25) were associated with increased risk of elevated BNP.

CONCLUSION

FI is associated with increased risks of both cardiovascular events and surrogated endpoint of cardiovascular disease-elevated BNP. Frailty may be a non-traditional risk factor of cardiovascular diseases and frailty index may be a measurement for early identifying high risk elderly individuals of cardiovascular abnormities.

Associations of sleep quality and sleep duration with frailty and pre-frailty in an elderly population Rugao longevity and ageing study

BACKGROUND

Previous studies suggest that poor sleep quality or abnormal sleep duration may be associated with frailty. Here we test the associations of sleep disturbances with both frailty and pre-frailty in an elderly population.

METHODS

Participants included 1726 community-dwelling elders aged 70-87 years. Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep disturbances. Frailty was defined using phenotype criteria. Logistic regression models were used to estimate odds ratio of the associations.

RESULTS

The average PSQI score was 5.4 (SD, 3.1). Overall 43.6% of the participants had poor sleep quality (PSQI> 5), 8.2% had night sleep time ≤ 5 h, and 27.8% had night sleep time ≥ 9 h. The prevalence of frailty and pre-frailty was 9.2 and 52.8%, respectively. The proportions of PSQI> 5 increased with the severity of frailty status (robust: pre-frail: frail, 34.5%: 48%: 56.1%, P < 0.001). After adjustment for multiple potential confounders, poor sleep quality (PSQI> 5) was associated with higher odds of frailty (OR = 1.78, 95% CI 1.19-2.66) and pre-frailty (OR = 1.51, 95% CI 1.20-1.90). Sleep latency, sleep disturbance, and daytime dysfunction components of PSQI measurements were also associated with frailty and pre-frailty. In addition, sleep time 9 h/night was associated with higher odds of frailty and pre-frailty.

CONCLUSIONS

We provided preliminary evidences that poor sleep quality and prolonged sleep duration were associated with being frailty and pre-frailty in an elderly population aged 70-87 years. The associations need to be validated in other elderly populations.

Genetic Variants of Homocysteine Metabolism, Homocysteine, and Frailty - Rugao Longevity and Ageing Study

OBJECTIVES

Recently, elevated homocysteine was reported to be associated with frailty in cross-sectional studies. However, whether homocysteine is causally associated with frailty is unknown. Here, we explore the inter-relationships between five non-synonymous genetic variants of homocysteine metabolic four genes, plasma homocysteine levels, and frailty.

METHOD

Data of 1480 individuals aged 70-87 years from the ageing arm of Rugao Longevity and Ageing Study were used. Five variants of the four homocysteine metabolic enzyme genes were genotyped. Frailty was defined using Fried's phenotype criteria.

RESULTS

The percentage of high homocysteine (>15μmol/L) is 33.3%. Two functional variants that decrease methylenetetrahydrofolate reductase (MTHFR) activities, C677T (Ala222Val, rs1801133) and A1298C (Glu429Ala, rs1801131), were significantly associated with increased homocysteine levels (β=-1.16, p=0.01; and β=1.46, p<0.001, respectively). In addition, homocysteine increase gradually from CC-CC, CC-AC, CT-AC, CT-AA, CC-AA, to TT-AA genotypes of the C677T-A1298C combinations. The five polymorphisms in the homocysteine metabolic gene was not associated with frailty. However, homocysteine was significantly associated with frailty with an OR of 2.27 (95% 1.36-3.78) for high homocysteine after adjusting for multiple confounding factors.

CONCLUSION

Elevated homocysteine is not a causal factor but a biomarker that manifests greater possibility of frailty in high risk elderly individuals for prevention.

Waist-Calf Circumference Ratio Is an Independent Risk Factor of HRQoL in Centenarians

PURPOSE

To analyze the associations between waist circumference (WC), body mass index (BMI), waist-hip ratio (WHR), waist-height ratio (WHtR), calf circumference, waist-calf circumference ratio (WCR), and quality of life in Hainan centenarians.

PATIENTS AND METHODS

A total of 1002 centenarians in Hainan were selected by a full sample survey. The EQ-5D visual analogue scale (EQ-5D-VAS) was used to investigate the quality of life. Restricted cubic splines were used to analyze and visualize the linear relationships.

RESULTS

After adjustment, the standard β values for BMI, WC, WHR, WHtR, calf circumference, and WCR associated with EQ-5D score were 0.101, 0.126, -0.018, 0.100, 0.302, and -0.219, respectively; all associations except for WHR were significant (P < 0.01). With increasing BMI, WC, and calf circumference, the risk of EQ-5D score <1 decreased (odds ratios [ORs] 0.91 [95% confidence interval (CI): 0.86-0.97), 0.97 [95% CI: 0.95-0.99], and 0.87 [95% CI: 0.82-0.92] after adjustment, respectively). With increasing WCR, the risk also increased (OR 2.70 [95% CI: 1.54-4.75]).

CONCLUSION

After excluding nutritional and muscle retention factors, fat central distribution negatively impacted the health-related quality of life of the oldest old population.

Associations of TNF-α -308 G>A and TNF-β 252 A>G with Physical Function and BNP-Rugao Longevity and Ageing Study

OBJECTIVES

To explore the associations of TNF-α -308 G>A (rs1800629) and TNF-β 252 A>G (rs909253) with physical function and plasma B-type natriuretic peptide (BNP).

METHODS

Data of 1747 community-dwelling elders from the ageing arm of the Rugao Longevity and Ageing Study was used. Physical function was measured by handgrip strength, Timed Up and Go (TUG) test and 5-meter walking test (5MWT).

RESULTS

AA genotype of the TNF-α -308 G>A was associated with higher mean time of TUG test and 5MWT (multivariable adjusted β=5.75 and 5.70, respectively, p<0.05), compared with GG genotype. For the TNF-β 252 A>G polymorphism, GG genotype was associated with higher mean time of TUG test and 5MWT (multivariable adjusted β=1.55 and 0.83, respectively, p<0.05) and lower handgrip strength (multivariable adjusted β=-0.69, p<0.05), compared with AA genotype. Further, GG was associated with greater odds of low handgrip strength (OR=1.47, 95% CI=1.06-2.04), low speed of TUG test (OR=1.87, 95% CI=1.20-2.01) and elevated BNP (OR=1.30, 95% CI=1.08-1.84). GG also interacted with elevated BNP to be associated with greater odds of low handgrip strength and 5MWT.

CONCLUSIONS

TNF-β 252 A>G was associated with physical function measurements, plasma BNP level, and odds of elevated BNP in an elderly population. TNF-β 252 A>G also interacted with elevated BNP to be associated with greater odds of physical function measurements.

Association between a frailty index based on common laboratory tests and QTc prolongation in older adults: the Rugao Longevity and Ageing Study

BACKGROUND

Risk factors for heart rate-corrected QT interval (QTc) proglongation should be explored to stratify high-risk individuals to aid the prevention of incident cardiovascular events and mortality. The diversity of risk factors for QTc prolongation suggests that use of the frailty index (FI), indicating general health deficits, may be an effective approach, especially in the elderly, to identify the risk of QTc prolongation.

METHODS

We used the data of 1,780 individuals aged 70-87 years from the Rugao Longevity and Ageing Study (RuLAS), a community-based longitudinal study. The FI was constructed using 20 routine laboratory tests, plus the body mass index and measures of systolic and diastolic blood pressures (FI-Lab).

RESULTS

The mean FI-Lab value was 0.24±0.09. The mean heart rate-corrected QT interval (QTc) was 407±38 ms. The prevalence of QTc prolongation was 5.2% in elderly community populations aged 70-87 years. A higher FI-Lab value was associated with a higher risk for QTc prolongation. Each 10% increase in the FI-Lab value increased the odds ratio (OR) by 33% (OR: 1.33; 95% CI: 1.07-1.64). Compared with the lowest quartile, the top quartile FI-Lab score was associated with a 2.50-fold QTc prolongation risk in elderly individuals (95% CI: 1.21-5.19).

CONCLUSION

An FI based on routine laboratory data can identify older adults at increased risk for QTc prolongation. The FI approach may therefore be useful for the risk stratification of QTc prolongation.

Association between serum β2-microglobulin levels and frailty in an elderly Chinese population: results from RuLAS

OBJECTIVE

To examine the association between serum β2-microglobulin (B2M) levels and frailty in an elderly Chinese population.

DESIGN

A population-based cohort study.

SETTING AND PARTICIPANTS

We used data on 1,663 elderly participants (aged 70-84 years) from the aging arm of the Rugao Longevity and Ageing study, a population-based observational two-arm cohort study conducted in Rugao, China.

MEASUREMENTS

The serum B2M was measured with chemiluminescence immunoassay by a technician in the biochemistry laboratory of the Rugao People's Hospital. Information on the frailty index and phenotype was collected.

RESULTS

The mean B2M levels and frailty index were 1.8 mg/L and 0.16, respectively; 188 (11.3%) participants were classified as frail (frailty phenotype). For a standard deviation increase in B2M, the adjusted odds ratio for frailty phenotype was 1.20 (95% CI: 1.05, 1.39; P=0.009) and the standardized coefficient for frailty index was 0.07 (95% CI: 0.02, 0.11; P=0.004). Relative to the lowest quartile, the highest B2M quartile had a greater risk of prevalent frailty with adjusted odds ratios of 1.68 (95% CI: 1.04, 2.71; P=0.034) for frailty phenotype and 1.51 (95% CI: 1.01, 2.27; P=0.044) for frailty index (≥0.25). In addition, estimated glomerular filtration rate (based on B2M) or chronic kidney disease (estimated glomerular filtration rate <60 mL/min/1.73 m²) was significantly associated with frailty phenotype and index.

CONCLUSION

B2M was significantly associated with both frailty phenotype and index in elderly Chinese population. The findings underscore the promising kidney relevant biomarkers for identifying vulnerable elderly Chinese population.

The KSR2-rs7973260 Polymorphism is Associated with Metabolic Phenotypes, but Not Psychological Phenotypes, in Chinese Elders

OBJECTIVE

To examine the associations between genetic variants of KSR2 (kinase suppressor of RAS)-rs7973260, RAPGEF6 (guanine nucleotide exchange factor 6)-rs3756290, LOC105377703-rs4481363, and subjective well-being (SWB) and depressive symptoms (DSs) in Chinese elders, which were recently associated in a genome-wide association study conducted in Caucasians. The pleiotropic effects of KSR2-rs7973260 on metabolic phenotypes were also explored.

MATERIALS AND METHODS

We used data from 1788 older individuals aged 70-84 years from the aging arm of the Rugao Longevity and Aging Study, a population-based cohort study conducted in the Jiangsu province of China.

RESULTS

No significant distributions of genotype frequencies were observed between life-satisfied and -unsatisfied groups across those with the three polymorphisms. The level of SWB components (positive affect, negative affect, and affect balance) and DSs did not differ among genotypes of the three variants. However, the presence of GA+AA of KSR2-rs7973260 was significantly higher in the metabolic syndrome (MetS), severe hypertriglyceridemia (HTG), and diabetes groups than in control groups (43.7% vs. 37.6%, 46.4% vs. 37.6%, 45.8% vs. 37.9%, respectively). The A allele of rs7973260 was associated with increased risk of MetS, severe HTG, and diabetes with an odds ratios (95% confidence intervals) of 1.289 (1.002-1.658), 1.438 (1.076-1.921), and 1.384 (1.022-1.875), which remained significant after multiple adjustments.

CONCLUSION

Rs7973260, rs3756290, and rs4481363 were not associated with SWB and DSs in Chinese elders. However, the KSR2-rs7973260 A allele exhibited pleiotropic effects on some metabolic phenotypes in Chinese elders. These effects should be validated in future studies.

Body mass index, waist circumference and waist-hip ratio are associated with depressive symptoms in older Chinese women: results from the Rugao Longevity and Ageing Study (RuLAS)

OBJECTIVE

The objective was to determine whether obesity is associated with depressive symptoms among older Chinese.

METHODS

Data from the cross-sectional Rugao Longevity and Ageing Study were used including anthropometric measurements (body mass index (BMI), waist circumference (WC) and waist-hip ratio (WHR)), socio-demographic characteristics, living habits, physical health and cognitive impairment. Depressive symptoms were assessed by the 15-item Geriatric Depression Scale (GDS-15). Chi-square tests and multivariate logistic regression analyses were performed to investigate the association between obesity and depressive symptoms.

RESULTS

Among 1732 elderly Chinese aged 70-84 years, the prevalence of depressive symptoms was 6.7% (5.0%-8.5%) in men and 12.5% (10.4%-14.6%) in women. A negative linear trend was found between depressive symptoms and BMI in women (P_{for trend} < 0.05). Women with BMI ≥ 28.0 kg/m² had lower chances (OR = 0.41 (0.20-0.84), p = 0.01) to have elevated depressive symptoms compared with their normal weight counterparts. Furthermore, consistent trends were observed with lower depression prevalence rates in higher WC and WHR categories in women. However, no such associations were apparent in men.

CONCLUSION

Higher BMI, WC and WHR categories were all associated with a lower risk of depressive symptoms in older women.

Associations of triglyceride levels with longevity and frailty: A Mendelian randomization analysis

Observational studies suggest associations of triglyceride levels with longevity and frailty. This study aimed to test whether the associations are causal. We used data from the Rugao Longevity and Ageing Study, a population-based cohort study performed in Rugao, China. A variant in the APOA5 gene region (rs662799) was used as the genetic instrument. Mendelian randomization (MR) analyses were performed to examine the associations of genetically predicted triglycerides with two ageing phenotypes – longevity ( ≥95 years) and frailty (modified Fried frailty phenotype and Rockwood frailty index). C allele of rs662799 was robustly associated with higher triglyceride levels in the comparison group (β = 0.301 mmol/L per allele, p < 0.001), with an F statistic of 95.3 and R² = 0.040. However MR analysis did not provide strong evidence for an association between genetically predicted triglyceride levels and probability of longevity (OR: 0.61; 95% CI: 0.35, 1.07 per 1 mmol/L increase in triglycerides). In the ageing arm (70–84 years), genetically predicted triglyceride levels were not associated with the frailty index (β = 0.008; 95% CI: −0.013, 0.029) or the frailty phenotype (OR: 1.91; 95% CI: 0.84, 4.37). In conclusion, there is currently a lack of sufficient evidence to support causal associations of triglyceride levels with longevity and frailty in elderly populations.

Association of CRP gene polymorphisms with CRP levels, frailty and co-morbidity in an elderly Chinese population: results from RuLAS

OBJECTIVES

to examine the associations of two common CRP gene polymorphisms with CRP levels, frailty and co-morbidity in an elderly Chinese population.

DESIGN

a population-based cohort study.

SETTING AND PARTICIPANTS

we obtained data on 1,723 elderly participants aged 70-84 from the ageing arm of the Rugao Longevity and Ageing study (RuLAS), a population-based observational cohort study conducted in Rugao, Jiangsu province, China.

MEASUREMENTS

the genotyping of two common CRP gene polymorphisms (rs1205 and rs3093059) was performed. Items concerning the frailty index and co-morbidity were collected.

RESULTS

the mean age of the study population was 75.3 ± 3.9 years, and 53.5% (n = 922) were women. The minor allele frequencies of rs1205 and rs3093059 were 42.4% (C allele) and 16.9% (C allele), respectively. The polymorphisms rs1205 and rs3093059 were significantly associated with CRP levels (β = 0.113 and 0.222, all P < 0.001). Non-significant association between rs1205 and rs3093059 and frailty, as well as between rs3093059 and co-morbidity was observed. However, SNP rs1205 CC genotype had an increased odds of co-morbidity compared with the TT genotype (odds ratio (OR):1.53; 95% confidence interval (CI): 1.16-2.02). Each additional copy of the C allele of SNP rs1205 was associated with 1.23 times (95% CI: 1.07-1.41) odds of co-morbidity. The significance remained after controlling for covariates such as education level, etc.

CONCLUSIONS

among elderly Chinese individuals, two CRP gene polymorphisms were significantly associated with CRP levels. However, none of them was associated with frailty. The preliminary findings warrant further validations.

Associations of sleep duration and sleep quality with life satisfaction in elderly Chinese: The mediating role of depression

This study investigated whether sleep duration and quality were related to life satisfaction (LS) among older Chinese adults and whether depression mediated those relationships. Cross-sectional data from the aging arm of the Rugao Longevity and Aging Study were used. Sleep duration, sleep quality, depression, LS and covariates were analyzed using logistic regressions. To assess the potential mediation of depression on the association between sleep duration and quality and LS, Aroian tests were used. Of 1756 older Chinese adults aged 70-84 years, 90.7% of the men and 83.3% of the women reported being satisfied with their lives. After adjusting for covariates, older adults who slept ≤6h per night were more likely to suffer from life dissatisfaction compared with those who slept 7-8h (OR=2.67, 95% CI 1.86-3.79), and individuals who slept poorly were almost 2 times (OR=2.91, 95% CI 2.16-3.91) more likely to have life dissatisfaction. The Aroian tests confirmed that these relationships were partially mediated by depression (p<0.001). Between short sleep and LS, the mediating effect of depression accounted for 13.9% of the total effects. Moreover, the mediating effect of depression on the association between sleep quality and LS was 13.3%. Short sleep duration and poor sleep quality were inversely associated with LS, and the relationships were partially mediated by depression. Our study suggests that both sleep and depression status are important factors for LS among the elderly.

C-reactive protein, frailty and overnight hospital admission in elderly individuals: A population-based study

BACKGROUND

C-reactive protein (CRP), an important inflammatory biomarker, has been linked to various diseases (e.g., cardiovascular disease). Here, we aimed to investigate the associations of high sensitivity C-reactive protein (hsCRP) with frailty and overnight hospital admission in an elderly Chinese population.

METHODS

We used cross-sectional data from 1478 participants (aged 70-84 years) who were randomly recruited from 31 villages in Jiang'an township, Rugao city, China. Frailty status was defined using a modified frailty phenotype. The number of overnight hospital admissions was ascertained.

RESULTS

The sample mean age was 75.3 years, and 53.0% of participants were female (n=784). The mean level of hsCRP was 3.6 mg/L. From the low (hsCRP≤1.00 mg/L) to high hsCRP (hsCRP≥3.0mg/L) group, the proportion of overnight hospital admission increased linearly (8.7%, 10.6%, vs. 15.5%; P for trend=0.007). For frailty, the age- and sex-adjusted odds ratios (ORs) were 1.21 (95% CI: 0.89, 1.64) for participants in the intermediate hsCRP group and 1.49 (95% CI: 1.05, 2.09) for participants in the high hsCRP group compared with those in the low hsCRP group. For overnight hospital admission, the corresponding ORs were 1.26 (95% CI: 0.72, 2.19) and 1.94 (95% CI: 1.08, 3.48), respectively. After adjustment for other covariates, the significance of these associations remained.

CONCLUSIONS

Elevated levels of hsCRP were associated with increased risks of frailty and overnight hospital admission among elderly individuals in Rugao. More public health concerns about inflammation and subsequent outcomes are needed to improve the quality of life in elderly populations.