Interactions between social/ behavioral factors and ADRB2 genotypes may be associated with health at advanced ages in China

Creatinine index as a predictive marker of sarcopenia in patients under hemodialysis

PURPOSE

Sarcopenia is a clinical condition that comprises declined skeletal muscle (SM) mass and SM strength, and is a risk factor for physical disability, impaired quality of life, and advanced morbidity and mortality in patients on hemodialysis (HD). The existing difficulty in evaluating SM mass and consequently of sarcopenia, with affordable and practical methods in clinical practice, is well established. The purpose of this study is to examine the creatinine index (CrI), a surrogate of SM mass, as a potential predictive marker of sarcopenia.

METHODS

In this cross-sectional study, we included 130 patients on HD with a mean age of 66.17 ± 12.47 years. SM mass and SM strength were evaluated with CrI and hand grip strength, respectively. Anthropometric, adiposity, nutritional, and biochemical assessments were also performed. Partial correlation and multivariate regression analyses were applied to investigate the association between CrI and SM strength.

RESULTS

Correlation analysis showed that mid-arm circumference, calf circumference, Geriatric nutritional index, and albumin-to-total protein ratio were positively associated with SM strength. Multivariate model indicated that CrI (β = 2.05, p < 0.001) and dialysis duration (β =- 0.53, p = 0.001) were independently related to SM strength. The significant positive correlation between CrI and SM strength remained unaffected even after adjusting for potential confounders.

CONCLUSIONS

Creatinine Index was significantly associated with SM strength highlighting its value as a new emerging practical in clinical setting sarcopenia predictive marker in HD patients.

Strategies and cognitive reserve to preserve lexical production in aging

In the absence of any neuropsychiatric condition, older adults may show declining performance in several cognitive processes and among them, in retrieving and producing words, reflected in slower responses and even reduced accuracy compared to younger adults. To overcome this difficulty, healthy older adults implement compensatory strategies, which are the focus of this paper. We provide a review of mainstream findings on deficient mechanisms and possible neurocognitive strategies used by older adults to overcome the deleterious effects of age on lexical production. Moreover, we present findings on genetic and lifestyle factors that might either be protective or risk factors of cognitive impairment in advanced age. We propose that "aging-modulating factors" (AMF) can be modified, offering prevention opportunities against aging effects. Based on our review and this proposition, we introduce an integrative neurocognitive model of mechanisms and compensatory strategies for lexical production in older adults (entitled Lexical Access and Retrieval in Aging, LARA). The main hypothesis defended in LARA is that cognitive aging evolves heterogeneously and involves complementary domain-general and domain-specific mechanisms, with substantial inter-individual variability, reflected at behavioral, cognitive, and brain levels. Furthermore, we argue that the ability to compensate for the effect of cognitive aging depends on the amount of reserve specific to each individual which is, in turn, modulated by the AMF. Our conclusion is that a variety of mechanisms and compensatory strategies coexist in the same individual to oppose the effect of age. The role of reserve is pivotal for a successful coping with age-related changes and future research should continue to explore the modulating role of AMF.

Allelic distribution of ABO gene in Chinese centenarians

Objective

Human ABO blood groups are determined by the alleles A, B, and O (O01 and O02) of the ABO gene and have been linked to the risks for cardiovascular diseases and cancers that affect lifespan.

We examined the genetic associations of the ABO gene and blood groups with longevity.

Methods

We inspected the frequencies of the A, B, O, and O02 alleles in a large Chinese centenarian population (n = 2201) and in middle‐aged controls (n = 2330). The single nucleotide polymorphisms were selected as allele A (rs507666), B (rs8176743, rs8176746, and rs8176749), O (rs687289), and O02 (rs688976, rs549446, and rs512770).

Results

Supported by allelic and genotypic association studies, the frequencies of blood types A, B, O, and AB in centenarian versus control participants were not statistically different: 0.2821 versus 0.2781 (χ² = 0.09, P = 0.76), 0.2867 versus 0.3060 (χ² = 2.03, P = 0.15), 0.3380 versus 0.3159 (χ² = 2.52, P = 0.11), and 0.0859 versus 0.0910 (χ² = 0.37, P = 0.54), respectively. Sex had little effect on these distributions.

Conclusion

Integrated with other previous reports, we conclude from this large Chinese cohort that genetic variants of the ABO gene and blood groups are not associated with longevity.

Association between exercise and the risk of dementia: results from a nationwide longitudinal study in China

OBJECTIVE

This study was conducted to examine the causal association between exercise and the risk of dementia among older Chinese adults.

DESIGN

Longitudinal population-based study with a follow-up duration of 9 years.

SETTING

Data for the Chinese Longitudinal Healthy Longevity Survey waves occurring from 2002 to 2011-2012 were extracted from the survey database.

PARTICIPANTS

In total, 7501 dementia-free subjects who were older than 65 years were included at baseline. Dementia was defined as a self-reported or proxy-reported physician's diagnosis of the disease.

OUTCOME MEASURES AND METHODS

Regular exercise and potential confounding variables were obtained via a self-report questionnaire. We generated longitudinal logistic regression models based on time-lagged generalised estimating equation to examine the causal association between exercise and dementia risk.

RESULTS

Of the 7501 older Chinese people included in this study, 338 developed dementia during the 9-year follow-up period after excluding those who were lost to follow-up or deceased. People who regularly exercised had lower odds of developing dementia (OR=0.53, 95% CI 0.33 to 0.85) than those who did not exercise regularly.

CONCLUSION

Regular exercise was associated with decreased risk of dementia. Policy-makers should develop effective public health programmes and build exercise-friendly environments for the general public.

Associations Between Neurotransmitter Genes and Fatigue and Energy Levels in Women After Breast Cancer Surgery

CONTEXT

Fatigue is a common problem in oncology patients. Less is known about decrements in energy levels and the mechanisms that underlie both fatigue and energy.

OBJECTIVES

In patients with breast cancer, variations in neurotransmitter genes between lower and higher fatigue latent classes and between the higher and lower energy latent classes were evaluated.

METHODS

Patients completed assessments before and monthly for six months after surgery. Growth mixture modeling was used to identify distinct latent classes for fatigue severity and energy levels. Thirty candidate genes involved in various aspects of neurotransmission were evaluated.

RESULTS

Eleven single-nucleotide polymorphisms or haplotypes (i.e., ADRB2 rs1042718, BDNF rs6265, COMT rs9332377, CYP3A4 rs4646437, GALR1 rs949060, GCH1 rs3783642, NOS1 rs9658498, NOS1 rs2293052, NPY1R Haplotype A04, SLC6A2 rs17841327, and 5HTTLPR + rs25531 in SLC6A4) were associated with latent class membership for fatigue. Seven single-nucleotide polymorphisms or haplotypes (i.e., NOS1 rs471871, SLC6A1 rs2675163, SLC6A1 Haplotype D01, SLC6A2 rs36027, SLC6A3 rs37022, SLC6A4 rs2020942, and TAC1 rs2072100) were associated with latent class membership for energy. Three of 13 genes (i.e., NOS1, SLC6A2, and SLC6A4) were associated with latent class membership for both fatigue and energy.

CONCLUSIONS

Molecular findings support the hypothesis that fatigue and energy are distinct, yet related symptoms. Results suggest that a large number of neurotransmitters play a role in the development and maintenance of fatigue and energy levels in breast cancer patients.

Demographics, phenotypic health characteristics and genetic analysis of centenarians in China

After a brief introduction to the background, significance and unique features of the centenarian population in China, we describe the Chinese Longitudinal Healthy Longevity Study (CLHLS), which is the world's largest study of centenarians, nonagenarians, octogenarians, and compatible young-old aged 65-79. Based on the CLHLS data and other relevant studies, we summarize demographic and socioeconomic characteristics as well as self-reported and objectively-tested health indicators of centenarians in China, with an emphasis on gender differences and rural/urban disparities. We then compare five-year-age-specific trajectories of physical and cognitive functions, self-reported health, and life satisfactions from ages 65-69 to 100+, concluding that good psychological resilience and optimism are keys to the exceptional longevity enjoyed by centenarians. We discuss recent findings of novel loci and pathways that are significantly associated with longevity based on the genome-wide association study (GWAS) of the CLHLS centenarian sample, which is 2.7 times as large as prior GWAS of longevity. We also highlight colleagues' and our own studies on longevity candidate genes and gene-environment interaction analyses. Finally, we discuss limitations inherent in our studies of centenarians in China and further research perspectives.

Novel loci and pathways significantly associated with longevity

Only two genome-wide significant loci associated with longevity have been identified so far, probably because of insufficient sample sizes of centenarians, whose genomes may harbor genetic variants associated with health and longevity. Here we report a genome-wide association study (GWAS) of Han Chinese with a sample size 2.7 times the largest previously published GWAS on centenarians. We identified 11 independent loci associated with longevity replicated in Southern-Northern regions of China, including two novel loci (rs2069837-IL6; rs2440012-ANKRD20A9P) with genome-wide significance and the rest with suggestive significance (P < 3.65 × 10(-5)). Eight independent SNPs overlapped across Han Chinese, European and U.S. populations, and APOE and 5q33.3 were replicated as longevity loci. Integrated analysis indicates four pathways (starch, sucrose and xenobiotic metabolism; immune response and inflammation; MAPK; calcium signaling) highly associated with longevity (P ≤ 0.006) in Han Chinese. The association with longevity of three of these four pathways (MAPK; immunity; calcium signaling) is supported by findings in other human cohorts. Our novel finding on the association of starch, sucrose and xenobiotic metabolism pathway with longevity is consistent with the previous results from Drosophilia. This study suggests protective mechanisms including immunity and nutrient metabolism and their interactions with environmental stress play key roles in human longevity.

Interaction Between the FOXO1A-209 Genotype and Tea Drinking Is Significantly Associated with Reduced Mortality at Advanced Ages

On the basis of the genotypic/phenotypic data from Chinese Longitudinal Healthy Longevity Survey (CLHLS) and Cox proportional hazard model, the present study demonstrates that interactions between carrying FOXO1A-209 genotypes and tea drinking are significantly associated with lower risk of mortality at advanced ages. Such a significant association is replicated in two independent Han Chinese CLHLS cohorts (p = 0.028-0.048 in the discovery and replication cohorts, and p = 0.003-0.016 in the combined dataset). We found the associations between tea drinking and reduced mortality are much stronger among carriers of the FOXO1A-209 genotype compared to non-carriers, and drinking tea is associated with a reversal of the negative effects of carrying FOXO1A-209 minor alleles, that is, from a substantially increased mortality risk to substantially reduced mortality risk at advanced ages. The impacts are considerably stronger among those who carry two copies of the FOXO1A minor allele than those who carry one copy. On the basis of previously reported experiments on human cell models concerning FOXO1A-by-tea-compounds interactions, we speculate that results in the present study indicate that tea drinking may inhibit FOXO1A-209 gene expression and its biological functions, which reduces the negative impacts of FOXO1A-209 gene on longevity (as reported in the literature) and offers protection against mortality risk at oldest-old ages. Our empirical findings imply that the health outcomes of particular nutritional interventions, including tea drinking, may, in part, depend upon individual genetic profiles, and the research on the effects of nutrigenomics interactions could potentially be useful for rejuvenation therapies in the clinic or associated healthy aging intervention programs.

Prevalence and correlates of successful ageing: a comparative study between China and South Korea

Successful ageing is often defined as a later life with less disease and disease-related disability, high level of cognitive and physical functions, and an active life style. Few studies have compared successful ageing across different societies in a non-Western social context. This study aims to compare prevalence and correlates of successful ageing between China and South Korea. The data come from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) and the Korean Longitudinal Study of Ageing (KLoSA). A total of 19,346 community-dwelling elders over 65 years were included, 15,191 from China and 4,155 from Korea. A multidimensional construct of successful ageing was used, with the criteria of no major comorbidity, being free of disability, good mental health, engaging in social or productive activity, and satisfaction on life. Correlates of successful ageing included demographics (gender, age, and rural/urban residence), socioeconomic features (financial status, education, and spouse accompany), and health behaviours (smoking, alcohol-drinking, and exercising). The results showed that 18.6 % of the older adults in China was successful agers, which was less than 25.2 % in Korea. When gender and age were adjusted, older adults were 51 % less likely to be successful agers in China than Korea (p < 0.001). The association patterns between successful ageing and its correlates are similar between China and Korea. However, before the socioeconomic variables are under control, rural residence was negatively related to successful ageing in China, whereas this is not the case in Korea. And the gender gap of successful ageing was mostly explained by socioeconomic features and health behaviours in Korea, but not in China. In both countries, good financial condition was highly associated with successful ageing. The study suggests that advancement of public health system could better control progression of non-communicable diseases among old people and thus promote successful ageing.