Association of leisure-time physical activity with cognition by apolipoprotein-E genotype in persons aged 60 years and over: the National Health and Nutrition Examination Survey (NHANES-III)

Steatotic liver disease-associated all-cause/cause-specific mortality in the United States

BACKGROUND

Recently, a panel of multi-society experts proposed steatotic liver disease (SLD) as an alternative terminology for metabolic dysfunction-associated fatty liver disease (MAFLD) or nonalcoholic fatty liver disease (NAFLD).

AIMS

We compared the impact of SLD, subtype of SLD, MAFLD and NAFLD on all-cause and cause-specific mortality.

METHODS

A total of 7811 individuals in the third National Health and Nutrition Examination Survey and linked mortality through 2019 were analysed. SLD was defined based on ultrasonographic hepatic steatosis. SLD, subtype of SLD and MAFLD were defined using the proposed definitions. The Cox proportional hazard model assessed all-cause/cause-specific mortality.

RESULTS

During a median follow-up of 27.1 years, individuals with SLD and MAFLD experienced approximately 13%-23% higher risk of all-cause mortality (hazard ratio [HR]: 1.15, 95% confidence interval [CI]: 1.02-1.29 for SLD; HR: 1.23, 95% CI: 1.09-1.38 for MAFLD; HR: 1.13, 95% CI: 1.01-1.27 for metabolic dysfunction-associated steatotic liver disease [MASLD]). Individuals with MetALD demonstrated a higher risk of all-cause (HR: 1.68, 95% CI: 1.10-2.57) and cancer-related mortality (HR: 2.40, 95% CI: 1.23-4.66). MASLD with advanced fibrosis had an increased risk of all-cause mortality compared to MASLD without advanced fibrosis.

CONCLUSIONS

SLD, especially MASLD and MetALD, is associated with increased all-cause mortality among adults in the US. Given this significant association between SLD or subtype of SLD (MASLD and MetALD) and all-cause mortality, adopting the proposed SLD criteria may help identify a sub-group of individuals with SLD who are at an increased risk for all-cause mortality.

Lower alanine aminotransferase levels are associated with increased all-cause and cardiovascular mortality in nonalcoholic fatty liver patients

BACKGROUND

Serum alanine aminotransferase (ALT) levels are often considered a marker to evaluate liver disease and its severity.

AIM

To investigate the association between ALT levels and all-cause and cause-specific mortality in patients with nonalcoholic fatty liver disease (NAFLD).

METHODS

The Third National Health and Nutrition Examination Survey (NHANES-III) from 1988 to 1994 and NHANES-III-related mortality data from 2019 onward were used to obtain the necessary data for the study. NAFLD was defined as hepatic steatosis, as diagnosed by ultrasound, with no other liver diseases. ALT levels were categorized into four groups according to the different recommended upper limits of normal (ULN) in men and women: < 0.5 ULN, 0.5-1 ULN, 1-2 ULN, and ≥ 2 ULN. The hazard ratios for all-cause mortality and cause-specific mortality were analyzed using the Cox proportional hazard model.

RESULTS

Multivariate logistic regression analysis demonstrated that the odds ratio of NAFLD correlated positively with increased serum ALT levels. In patients with NAFLD, all-cause mortality and cardiovascular mortality were the highest when ALT was < 0.5 ULN, yet cancer-related mortality was the highest when ALT was ≥ 2 ULN. The same results could be found in both men and women. Univariate analysis showed that severe NAFLD with normal ALT levels had the highest all-cause and cause-specific mortality, but the difference was not statistically significant after adjustment for age and multivariate factors.

CONCLUSION

The risk of NAFLD was positively correlated with ALT level, but all-cause and cardiovascular mortality were the highest when ALT was < 0.5 ULN. Regardless of the severity of NAFLD, normal or lower ALT levels were associated with higher mortality than elevated ALT levels. Clinicians should be aware that high ALT levels indicate liver injury, but low ALT levels are associated with a higher risk of death.

Impact of Thyroid Function on the Prevalence and Mortality of Metabolic Dysfunction-Associated Fatty Liver Disease

CONTEXT

Thyroid function variation within the thyroxine reference range has negative metabolic effects. Metabolic dysfunction-associated fatty liver disease (MAFLD) is a recently proposed definition.

OBJECTIVE

We aim to explore the effects of thyroid function status on prevalence and mortality of MAFLD.

METHODS

Data of 10 666 participants from the Third National Health and Nutrition Examination Survey (NHANES III) were used. MAFLD was diagnosed based on the new definition. Thyroid function variation within the thyroxine reference range was defined based on thyroid-stimulating hormone (TSH) levels: subclinical hyperthyroidism, <0.39 mIU/L; strict-normal thyroid function, 0.39-2.5 mIU/L; and low thyroid function, >2.5 mIU/L, which comprised low-normal thyroid function (2.5-4.5 mIU/L) and subclinical hypothyroidism (> 4.5 mIU/L). Logistic and Cox regression were used in multivariate analysis.

RESULTS

Low thyroid function is independently associated with MAFLD (odds ratio: 1.27). Compared with strict-normal thyroid function, subclinical hypothyroidism was significantly associated with increased risk for all-cause and cardiovascular mortality in the total population (hazard ratio [HR] for all-cause: 1.23; cardiovascular: 1.65) and MAFLD population (HR for all-cause: 1.32; cardiovascular: 1.99); meanwhile, in the low-normal thyroid function group, an increasing trend in mortality risk was observed. Furthermore, low thyroid function also showed significant negative impact on mortality in the total and MAFLD population. Among thyroid function spectrum, mild subclinical hypothyroidism showed the highest HRs on mortality.

CONCLUSIONS

Low thyroid function is independent risk factor of MAFLD and is associated with increased risk for all-cause and cardiovascular mortality in the MAFLD population. Reevaluation of TSH reference range should be considered.

Gallstone Disease and Its Association With Nonalcoholic Fatty Liver Disease, All-Cause and Cause-Specific Mortality

BACKGROUND & AIMS

Presence of gallstone disease may influence outcomes in patients with nonalcoholic fatty liver disease (NAFLD). We studied the impact of gallstone disease on mortality in individuals with and without NAFLD.

METHODS

Prospective cohort study used the Third National Health and Nutrition Examination Survey (1988-1994) with mortality data through 2015. Gallstone disease was defined as ultrasonographic evidence of gallstones or absence of the gallbladder (prior cholecystectomy). NAFLD was defined using standardized ultrasonographic criteria.

RESULTS

Gallstone disease and cholecystectomy were independently associated with NAFLD (odds ratio [OR], 1.75; 95% confidence interval [CI], 1.43-2.15 for gallstone disease and OR, 2.77; 95% CI, 2.01-3.83 for cholecystectomy compared with no gallstone disease). During the median follow-up of 23 years, gallstone disease was associated with a higher risk of all-cause mortality (hazard ratio [HR], 1.19; 95% CI, 1.05-1.37) and cause-specific mortality. Gallstone disease was associated with a higher risk of all-cause mortality in non-NAFLD sub-cohort (HR, 1.42; 95% CI, 1.23-1.64) but not in NAFLD (HR, 1.03; 95% CI, 0.87-1.22). Gallstone disease was associated with a higher risk of cardiovascular-related (HR, 1.40; 95% CI, 1.10-1.78) and cancer-related (HR, 1.71; 95% CI, 1.18-2.48) mortality in non-NAFLD sub-cohort. Gallstone disease was associated with increased cardiovascular mortality (HR, 1.36; 95% CI, 1.05-1.77) in NAFLD.

CONCLUSIONS

Gallstone disease is an independent risk factor for NAFLD, but gallstone disease is not associated with all-cause mortality in individuals with NAFLD. Screening for gallstone disease in individuals at risk for developing NAFLD may help with risk stratification for all-cause mortality related to gallstone disease.

Association of fall rate and functional status by APOE genotype in cancer survivors after exercise intervention

PURPOSE/OBJECTIVES

Cancer treatment survivors often report impaired functioning and increased falls. Not all survivors experience the same symptom burden, suggesting individual susceptibilities. APOE genotype is a potential genetic risk factor for cancer treatment related side effects. Lifestyle factors such as physical activity can mitigate the effect of APOE genotype on measures of clinical interest in individuals without a history of cancer. We tested the hypothesis that APOE genotype influences cancer treatment related side effects and symptoms as well as response to exercise intervention.

MATERIALS AND METHODS

Data from a subsample of a study of fall prevention exercise in post-treatment female cancer survivors aged 50-75 years old (https://clinicaltrials.gov NCT01635413) were used to conduct a secondary data analysis. ApoE genotype was determined by serum sampling. Physical functioning, frequency of falls, and symptom burden were assessed using survey instruments.

RESULTS

Data from 126 female cancer survivors a median of 49 months out from cancer diagnosis were analyzed. ApoE4 carriers trended toward a higher fall rate at baseline (p = 0.059), but after exercise intervention had a fall rate lower than E4 non-carriers both immediately after structured intervention (p = 0.013) and after 6 months of follow up (p = 0.002). E2 carriers did not show improved measures of depressive symptoms and self-report disability after exercise intervention. E3 homozygotes showed increased self report physical activity after the 6 month exercise intervention, but E4 and E2 carriers did not.

CONCLUSIONS

APOE genotype may modulate cancer treatment related side effects and symptoms and response to exercise intervention.

Apolipoprotein E Genotype Moderation of the Association Between Physical Activity and Brain Health. A Systematic Review and Meta-Analysis

Introduction

Possession of one or two e4 alleles of the apolipoprotein E (APOE) gene is associated with cognitive decline and dementia risk. Some evidence suggests that physical activity may benefit carriers of the e4 allele differently.

Method

We conducted a systematic review and meta-analysis of studies which assessed APOE differences in the association between physical activity and: lipid profile, Alzheimer's disease pathology, brain structure and brain function in healthy adults. Searches were carried out in PubMed, SCOPUS, Web of Science and PsycInfo.

Results

Thirty studies were included from 4,896 papers screened. Carriers of the e4 allele gained the same benefit from physical activity as non-carriers on most outcomes. For brain activation, e4 carriers appeared to gain a greater benefit from physical activity on task-related and resting-state activation and resting-state functional connectivity compared to non-carriers. Post-hoc analysis identified possible compensatory mechanisms allowing e4 carriers to maintain cognitive function.

Discussion

Though there is evidence suggesting physical activity may benefit e4 carriers differently compared to non-carriers, this may vary by the specific brain health outcome, perhaps limited to brain activation. Further research is required to confirm these findings and elucidate the mechanisms.

Cognitive Aging and the Promise of Physical Activity

Is the field of cognitive aging irretrievably concerned with decline and deficits, or is it shifting to emphasize the hope of preservation and enhancement of cognitive function in late life? A fragment of an answer comes from research attempting to understand the reasons for individual variability in the extent and rate of cognitive decline. This body of work has created a sense of optimism based on evidence that there are some health behaviors that amplify cognitive performance or mitigate the rate of age-related cognitive decline. In this context, we discuss the role of physical activity on neurocognitive function in late adulthood and summarize how it can be conceptualized as a constructive approach both for the maintenance of cognitive function and as a therapeutic for enhancing or optimizing cognitive function in late life. In this way, physical activity research can be used to shape perceptions of cognitive aging. Expected final online publication date for the Annual Review of Clinical Psychology, Volume 18 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Metabolic dysfunction-associated fatty liver disease is associated with increased all-cause mortality in the United States

BACKGROUND & AIMS

Recently, international experts proposed redefining non-alcoholic fatty liver disease (NAFLD) as metabolic dysfunction-associated fatty liver disease (MAFLD), based on modified criteria. It is suspected that outcomes such as mortality may differ for these clinical entities. We studied the impact of MAFLD and NAFLD on all-cause and cause-specific mortality in US adults.

METHODS

We analyzed data from 7,761 participants in the Third National Health and Nutrition Examination Survey and their linked mortality through 2015. NAFLD was diagnosed by ultrasonographic evidence of hepatic steatosis without other known liver diseases. MAFLD was defined based on the criteria proposed by an international expert panel. The Cox proportional hazard model was used to study all-cause mortality and cause-specific mortality between MAFLD and NAFLD, with adjustments for known risk factors.

RESULTS

During a median follow-up of 23 years, individuals with MAFLD had a 17% higher risk of all-cause mortality (hazard ratio [HR] 1.17; 95% CI 1.04-1.32). Furthermore, MAFLD was associated with a higher risk of cardiovascular mortality. NAFLD per se did not increase the risk of all-cause mortality. Individuals who met both definitions had a higher risk of all-cause mortality (HR 1.13, 95% CI 1.00-1.26), while individuals who met the definition for MAFLD but not NAFLD had a 1.7-fold higher risk of all-cause mortality (HR 1.66, 95% CI 1.19-2.32). Estimates for all-cause mortality were higher for those with advanced fibrosis and MAFLD than for those with advanced fibrosis and NAFLD.

CONCLUSIONS

In this US population-based study, MAFLD was associated with an increased risk of all-cause mortality, while NAFLD demonstrated no association with all-cause mortality after adjusting for metabolic risk factors.

LAY SUMMARY

Our findings provide further support for the idea that non-alcoholic fatty liver disease (NAFLD) is a part of a broader multi-system disease that also includes obesity, diabetes, high blood pressure, and high cholesterol. Therefore, re-defining NAFLD as metabolic dysfunction-associated fatty liver disease (MAFLD) may help improve our understanding of predictors that increase the risk of death.

Longitudinal Effects of Physical Activity Change on Hippocampal Volumes over up to 12 Years in Middle and Older Age Community-Dwelling Individuals

The objectives of this study were to investigate the long-term associations between changes in physical activity levels and hippocampal volumes over time, while considering the influence of age, sex, and APOE-ε4 genotype. We investigated the effects of change in physical activity on hippocampal volumes in 411 middle age (mean age = 47.2 years) and 375 older age (mean age = 63.1 years) adults followed up to 12 years. An annual volume decrease was observed in the left (middle age: 0.46%; older age: 0.51%) but not in the right hippocampus. Each additional 10 metabolic equivalents (METs, ~2 h of moderate exercise) increase in weekly physical activity was associated with 0.33% larger hippocampal volume in middle age (equivalent to ~1 year of typical aging). In older age, each additional MET was associated with 0.05% larger hippocampal volume; however, the effects declined with time by 0.005% per year. For older age APOE-ε4 carriers, each additional MET was associated with a 0.10% increase in hippocampal volume. No sex effects of physical activity change were found. Increasing physical activity has long-term positive effects on hippocampal volumes and appears especially beneficial for older APOE-ε4 carriers. To optimize healthy brain aging, physical activity programs should focus on creating long-term exercise habits.

Sarcopenia in nonalcoholic fatty liver disease and all-cause and cause-specific mortality in the United States

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD) has been associated with sarcopenia. However, mortality in the setting of NAFLD-related sarcopenia remains undefined. We aim to determine the all-cause and cause-specific mortality from sarcopenia among adults with NAFLD in the USA.

METHODS

11 065 individuals in the Third National Health and Nutrition Examination Survey were studied and linked mortality through 2015 was analysed. NAFLD was diagnosed based on presence of ultrasonographic hepatic steatosis without other known liver diseases. Sarcopenia was defined as skeletal muscle index determined by bioelectrical impedance analysis. The Cox proportional hazard model was used to assess all-cause mortality and cause-specific mortality, and hazard ratio (HR) adjusted for known risk factors.

RESULTS

During a median follow-up of 23 years or more, sarcopenia was associated with increased all-cause mortality (HR 1.27, 95% confidence interval [CI] 1.11-1.44). Only in individuals with NAFLD, sarcopenia was associated with a higher risk for all-cause mortality, while this association was absent in those without NAFLD. Individuals with both sarcopenia and NAFLD had a higher risk for all-cause mortality (HR 1.28 95% CI 1.06-1.55) compared with those without sarcopenia and NAFLD. Furthermore, sarcopenia was associated with a higher risk for cancer- and diabetes-related mortality among those with NAFLD. This association was not noted in those without NAFLD.

CONCLUSION

In this nationally representative sample of US adults, sarcopenia was associated with a higher risk for all-cause, cancer- and diabetes-related mortality in individuals with NAFLD.

Hippocampal maintenance after a 12-month physical activity intervention in older adults: The REACT MRI study

BACKGROUND

Physical activity interventions have had varying results on modifying hippocampal volume.

METHODS

The Retirement in Action (REACT) study conducted a randomised-controlled trial of a 12-month physical activity and behaviour maintenance intervention in older adults at risk of mobility impairments. The physical activity sessions were delivered twice weekly for the first twelve weeks, and then reduced to once weekly, to groups of 15 participants. Activities included cardiovascular, strength, balance and flexibility exercises. A sub-sample of participants in the physical activity (N = 54) and control arms (N = 48) underwent a 3 T MRI brain scan and cognitive assessments at baseline, 6- and 12-months (mean age = 76.6 years, 6.8 SD). It was hypothesised that the intervention would lead to a reduced rate of decline in hippocampal volume. Group differences in changes in cognition were also examined.

RESULTS

As hypothesised, we found a maintenance in left hippocampal volume in the intervention arm, in comparison with the control arm after 12 months (p = 0.027). In a secondary analysis, this effect was attenuated after including age, sex and education level as covariates (p = 0.057). There was no significant between-group difference in the right hippocampus (p = 0.405). Contrary to our hypothesis, we did not find a beneficial effect of the intervention on cognitive outcomes.

CONCLUSIONS

Our findings suggest that a community-based physical activity intervention can significantly ward-off hippocampal atrophy in older adults. While the lack of effects on cognition may limit the interpretability of our results, our findings of hippocampal maintenance are promising given the potential clinical relevance of protecting the hippocampus from age-related decline.

The influence of a 16-week exercise program, APOE status, and age on executive function task performance: A randomized trial

Previous research has shown beneficial cognitive changes following exercise training in older adults. However, the work on the potential moderating effects of Apoliprotein E (APOE) ε4 carrier status has been mixed, and the role of exercise intensity remains largely unexplored. The present study sought to examine the influence of APOE ε4 status and exercise intensity on measures of cognitive performance in a group of older adults. Cross-sectional comparisons between a group of younger inactive adults (n = 44, age = 28.86 ± 0.473 SD, 60.5% female) and a group of older inactive adults (n = 142, age = 67.8 ± 5.4, 62.7% female) were made on baseline measurements of APOE ε4 status, VO₂peak, and cognitive performance in the domain of executive functioning. The older adults also participated in a randomized controlled exercise trial, exercising three times per week for 16-weeks in either a low-intensity continuous training (LICT) group or a moderate-intensity continuous training plus interval training (MICT+IT) group at the Center for Health and Neuroscience, Genes, and Environment (CUChange) Exercise Laboratory. Follow-up measurements of VO₂peak and cognitive performance were collected on the older adults after the exercise intervention. Cross-sectional comparisons between the older and younger adults demonstrated significant impairments among older adults in Stroop effect on error and time, Category Switch mixing effects, and Keep Track task. This impairment was not moderated by APOE ε4 carrier status. Improvements from pre- to post-exercise intervention were observed in both exercise groups in Stroop effect on error ([F (1, 256) = 9.381, p < 0.01, η² = 0.031]) and Category Switch switching effect reaction time ([F(1, 274) = 4.442, p < 0.05, η² = 0.020]), with no difference between exercise groups. The moderating effects of APOE ε4 carrier status were mixed. Exercise did not improve the Stroop effect on error among ε4 carriers assigned to MICT+IT when improvements were seen in all other groups. Further research is needed to examine the mechanisms of action by which exercise impacts cognitive task performance, and possible moderators such as genetic variability and exercise intensity.

Physical fitness mediates the association between age and cognition in healthy adults

BACKGROUND

Physical fitness is an important contributor to healthy aging that improves cognition. Older adults who engage in cardiorespiratory fitness activities show less cognitive decline.

AIMS

To examine whether physical fitness acts as a potential protective mechanism shielding against the negative associations between age and cognition. Specifically, we examined whether physical fitness mediates the relationship between age and processing speed.

METHODS

114 (M = 63.80, SD = 10.63) senior executives completed a computerized cognitive battery composed of four processing speed tasks. Level of physical fitness was assessed on a treadmill stress test and reported in metabolic equivalents (METs).

RESULTS

Older age was associated with slower processing speed (r = 0.25, p = 0.007), whereas greater physical fitness was associated with faster processing speed (r = -0.30, p = 0.001). Path analysis indicated that the association between age and processing speed was fully mediated by the level of physical fitness (Indirect effect: β = 0.10, p = 0.008; Direct effect: β = 0.16, p = 0.20).

CONCLUSIONS AND DISCUSSION

The findings indicate that physical fitness is a strong mediator of the relationship between age and processing speed and imply that physical fitness makes a major contribution to cognitive reserve during the aging process. The results may suggest that the decrease in physical fitness during aging may partially account for slower cognitive processing.

Low Thyroid Function in Nonalcoholic Fatty Liver Disease Is an Independent Predictor of All-Cause and Cardiovascular Mortality

INTRODUCTION

Higher levels of thyroid-stimulating hormone (TSH) in the euthyroid state can negatively affect the metabolic health, including nonalcoholic fatty liver disease (NAFLD). We studied the effect of TSH levels in the setting of normal levels of thyroid hormone on all-cause and cause-specific mortality stratified by NAFLD status.

METHODS

The National Health and Nutrition Examination Survey (NHANES) III from 1988 to 1994 and NHANES III-linked mortality data through 2015 were used. NAFLD was defined as ultrasonographically diagnosed hepatic steatosis without coexisting liver diseases. Subclinical hypothyroidism was defined as a TSH level over 4.5 mIU/L and "low-normal" thyroid function as higher TSH level (2.5-4.5 mIU/L) within the euthyroid reference range. The Cox proportional hazard model analyzed the all-cause mortality and cause-specific mortality.

RESULTS

In a multivariate logistic regression analysis, individuals with low thyroid function demonstrated an association with NAFLD in a dose-dependent manner. During a median follow-up of 23 years, low thyroid function was associated with increased all-cause mortality only in the univariate model. Low thyroid function was associated with a higher risk for all-cause mortality in individuals with NAFLD and not in those without NAFLD. Furthermore, low thyroid function was associated with a higher risk for cardiovascular mortality in the entire population and among those with NAFLD but demonstrated no association with the non-NAFLD group.

DISCUSSION

In this large nationally representative sample of American adults, low thyroid function was associated with NAFLD and a predictor of higher risk for all-cause and cardiovascular mortality in individuals with NAFLD.

Diet quality and its association with nonalcoholic fatty liver disease and all-cause and cause-specific mortality

BACKGROUND & AIMS

Healthy diet has been recommended for nonalcoholic fatty liver disease (NAFLD), although it is not clear whether improving diet quality can prevent mortality. We aim to assess the impact of quality of diet on NAFLD and mortality in subjects with and without NAFLD.

METHODS

We performed cohort study using the Third National Health and Nutrition Examination Survey from 1988 to 1994 and linked mortality data through 2015. We used the Healthy Eating Index (HEI) scores to define diet quality, with higher HEI scores (Q4) indicating better adherence to dietary recommendations. NAFLD was defined as ultrasonographic hepatic steatosis.

RESULTS

Multivariate analysis showed that subjects with higher diet quality were inversely associated with NAFLD in a dose-dependent manner. During the median follow-up of 23 years, having a higher diet quality was associated with reduction in risk of all-cause mortality in the age, sex, Race/ethnicity-adjusted hazard ratio (HR) (Q4, HR: 0.60, 95% CI: 0.52-0.68) and the multivariate model (Q4, HR: 0.81, 95% CI: 0.71-0.92). Higher diet quality was associated with a lower risk for all-cause mortality in subjects without NAFLD; however, this protective association with diet quality was not noted in those with NAFLD. Furthermore, a high diet quality was associated with a lower risk for cancer-related mortality in the total population and among those without NAFLD. This association was not noted in those with NAFLD.

CONCLUSIONS

High diet quality was inversely associated with NAFLD and was positively associated with a lower risk for cancer-related and all-cause mortality in those without NAFLD.

ApoE Genotype, Lipid Profile, Exercise, and the Associations With Cardiovascular Morbidity and 18-Year Mortality

Background

Studies of longevity examined apolipoprotein E (ApoE), a gene involved in lipoprotein metabolism, which interacts with susceptibility to age-related diseases, and with mortality. We evaluated the association of ApoE isoforms with cardiovascular disease (CVD) and all-cause mortality.

Methods

A prospective cohort of 949 survivors of the Israel Study of Glucose Intolerance, Obesity, and Hypertension, examined during 1999–2004, mean age 72 years, was followed for mortality until 2017. Participants were interviewed for lifestyle habits and medical history. Anthropometrics and biochemical markers were taken. Logistic regression was used to assess CVD morbidity and Cox proportional hazard model for mortality.

Results

The most common genotype in the cohort was ApoE E3 (76.3%), with the other two almost equally distributed (ApoE E2 11.2% and ApoE E4 12.5%). In men only, ApoE E4 associated with CVD (adjusted odds ratio = 1.46, 95% confidence interval [CI] 0.76, 2.80) and with 18-year mortality (adjusted hazard ratio = 1.47, 95% CI 0.95, 2.26), adjusting for age, ethnicity, physical activity, hypertension, diabetes, low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol, triglycerides and lipid-lowering medications. Low levels of HDL cholesterol, adjusted for ApoE and the above-mentioned variables, associated with higher prevalence of CVD (adjusted odds ratio = 1.35, 95% CI 1.00, 1.83) and all-cause mortality (adjusted hazard ratio = 1.42, 95% CI 1.14, 1.78). ApoE E3 and E2 conferred a lower 18-year mortality risk in the physically active individuals, compared to the sedentary (adjusted hazard ratio = 0.57, 95% CI 0.44, 0.74, and adjusted hazard ratio = 0.53, 95% CI 0.78, 1.02, respectively).

Conclusions

In community-dwelling older adults, sociodemographic characteristics and physical activity, blood pressure and HDL-cholesterol levels, may outweigh the impact of ApoE polymorphisms on CVD morbidity and all-cause mortality.

Associations between sarcopenia and nonalcoholic fatty liver disease and advanced fibrosis in the USA

BACKGROUND AND AIM

Nonalcoholic fatty liver disease (NAFLD) may be associated with sarcopenia. This study aims to determine whether sarcopenia is independently associated with NAFLD and advanced fibrosis.

PARTICIPANTS AND METHODS

Cross-sectional data from 11 325 participants in the third National Health and Nutrition Examination Survey were analyzed. NAFLD was defined as the presence of hepatic steatosis from the ultrasound. Sarcopenia was defined as the skeletal muscle index.

RESULTS

NAFLD was more common in participants with sarcopenia than in those without (46.7 vs. 27.5%). Univariate analysis showed that sarcopenia was associated with NAFLD [odds ratio (OR): 2.31; 95% confidence interval (CI): 2.01-2.64], which remained significant after adjustment for age, sex, ethnicity, metabolic risk factors (OR: 1.24; 95% CI: 1.03-1.48). This finding persisted after adjustment for C-reactive protein as a marker of chronic inflammation. NAFLD-associated advanced fibrosis was more common in participants with sarcopenia than in those without (7.8 vs. 1.6%). Sarcopenia was associated with NAFLD-associated advanced fibrosis independent of metabolic risk factors (OR: 1.79; 95% CI: 1.18-2.72).

CONCLUSION

Sarcopenia was independently associated with increased odds of NAFLD and NAFLD-associated advanced fibrosis independent of well-defined risk factors. Interventions to strengthen muscle mass may reduce the burden of NAFLD and advanced fibrosis.

The interaction of nonalcoholic fatty liver disease and smoking on mortality among adults in the United States

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD) has become the most common liver disease in Western countries. Smoking and diabetes mellitus (DM) have been shown to increase mortality; however, whether NAFLD adds to the detrimental effect of smoking in DM and non-DM patients is unknown. We evaluated the possible interactive effect of NAFLD and smoking on mortality risk in a US population-based sample.

METHODS

Cross-sectional data from 11 205 participants in the third National Health and Nutrition Examination Survey were analysed. NAFLD was defined as ultrasonographic hepatic steatosis without evidence of other liver diseases. Proportional hazards regression modelling was used to test for the multiplicative interaction of NAFLD and smoking on overall mortality, controlling for DM.

RESULTS

36.5% of the participants had NAFLD of whom 21.1% were current smokers, while among non-NAFLD subjects, 26.2% reported current smoking. Smoking was associated with a hazard ratio (HR) of 2.23 (95% confidence interval (CI): 1.87-2.65) among non-NAFLD subjects, and 2.31 (95% CI: 1.33-2.92, P < 0.01) among NAFLD patients. In contrast, the HR for NAFLD was 1.01 (95% CI: 0.78-1.31, P = 0.96) among smokers and 0.98 (95% CI: 0.87-1.10, P = 0.73) among non-smokers. There was no evidence of interaction between NAFLD and smoking (HR = 1.01, 95% CI: 0.74-1.38, P = 0.94) in the combined model.

CONCLUSION

We found that smoking increased mortality by two-fold among the US population. Although the magnitude of the increase in mortality did not differ from that in non-NAFLD subjects, smoking represents a modifiable determinant of long-term outcomes in NAFLD patients.

The Impact of Multiple Dimensions of Socioeconomic Status on Physical Functioning Across the Life Course

Objective: We used the Physical Performance Across the LifeSpan Study to investigate the relationships of multiple indicators of socioeconomic status (SES), both in early life and late life, with physical function. Method: We examined associations between multiple early and late life SES indicators with physical function measured by aerobic endurance, gait speed, and lower body strength. Results: Higher participant education and household income were associated with increased physical function. In our age-stratified analysis, we observed widening SES disparities with increasing age among those in the two younger strata with lower SES associated with worse physical function. Finally, we observed an association between socioeconomic trend and gait speed, aerobic endurance, and lower body strength. There was also an association between lower aerobic endurance and being in a downward socioeconomic trend. Discussion: These findings highlight the significance of considering multiple dimensions of the social environment as important correlates of physical functioning across the life course.

RNA-Sequencing Reveals Unique Transcriptional Signatures of Running and Running-Independent Environmental Enrichment in the Adult Mouse Dentate Gyrus

Environmental enrichment (EE) is a powerful stimulus of brain plasticity and is among the most accessible treatment options for brain disease. In rodents, EE is modeled using multi-factorial environments that include running, social interactions, and/or complex surroundings. Here, we show that running and running-independent EE differentially affect the hippocampal dentate gyrus (DG), a brain region critical for learning and memory. Outbred male CD1 mice housed individually with a voluntary running disk showed improved spatial memory in the radial arm maze compared to individually- or socially-housed mice with a locked disk. We therefore used RNA sequencing to perform an unbiased interrogation of DG gene expression in mice exposed to either a voluntary running disk (RUN), a locked disk (LD), or a locked disk plus social enrichment and tunnels [i.e., a running-independent complex environment (CE)]. RNA sequencing revealed that RUN and CE mice showed distinct, non-overlapping patterns of transcriptomic changes versus the LD control. Bio-informatics uncovered that the RUN and CE environments modulate separate transcriptional networks, biological processes, cellular compartments and molecular pathways, with RUN preferentially regulating synaptic and growth-related pathways and CE altering extracellular matrix-related functions. Within the RUN group, high-distance runners also showed selective stress pathway alterations that correlated with a drastic decline in overall transcriptional changes, suggesting that excess running causes a stress-induced suppression of running’s genetic effects. Our findings reveal stimulus-dependent transcriptional signatures of EE on the DG, and provide a resource for generating unbiased, data-driven hypotheses for novel mediators of EE-induced cognitive changes.

A randomized controlled trial of physical activity with individual goal-setting and volunteer mentors to overcome sedentary lifestyle in older adults at risk of cognitive decline: the INDIGO trial protocol

BACKGROUND

Increasing physical activity (PA) effectively in those who are inactive is challenging. For those who have subjective memory complaints (SMC) or mild cognitive impairment (MCI) this is a greater challenge necessitating the need for more engaging and innovative approaches. The primary aim of this trial is to determine whether a home-based 6-month PA intervention with individual goal-setting and peer mentors (GM-PA) can significantly increase PA levels in insufficiently active older adults at increased risk of developing Alzheimer's disease (AD).

METHODS

Community living 60-80 year olds with SMC or MCI who do not engage in more than 60 min per week of moderate intensity PA will be recruited from memory clinics and the community via media advertisements to participate in this randomized, single-blind controlled trial. All participants will receive an individually tailored home-based PA program of 150 min of moderate intensity walking/week for 6 months. The intervention group will undertake individual goal-setting and behavioral education workshops with mentor support via telephone (GM-PA). Those randomized to the control group will have standard education workshops and Physical Activity Liaison (PAL) contact via telephone (CO-PA). Increase in PA is the primary outcome, fitness, cognitive, personality, demographic and clinical parameters will be measured and a health economic analysis performed. A saliva sample will be collected for APOE e4 genotyping. All participants will have a goal-setting interview to determine their PA goals. Active volunteers aged 50-85 years will be recruited from the community randomized and trained to provide peer support as mentors (intervention group) or PALS (control group) for the 6-month intervention. Mentors and PALS will have PA, exercise self-efficacy and mentoring self-efficacy measured. Participants in both groups are asked to attend 3 workshops in 6 months. At the first workshop, they will meet their allocated Mentor or PAL who will deliver their respective programs and support via 6 telephone calls during the intervention.

DISCUSSION

If the GM-PA program is successful in increasing the PA levels of the target group it will potentially provide another strategy and community resource that can be translated into practice.

TRIAL REGISTRATION

Australia New Zealand Clinical Trials Registry ACTRN12613001181796 . (29/10/2013) retrospectively registered.

The effect of an interactive cycling training on cognitive functioning in older adults with mild dementia: study protocol for a randomized controlled trial

BACKGROUND

To date there is no cure or an effective disease-modifying drug to treat dementia. Available acetylcholine-esterase inhibiting drugs or memantine only produce small benefits on cognitive and behavioural functioning and their clinical relevance remains controversial. Combined cognitive-aerobic interventions are an appealing alternative or add-on to current pharmacological treatments. The primary aim of this study is to investigate the efficacy of a combined cognitive-aerobic training and a single aerobic training compared to an active control group in older adults with mild dementia. We expect to find a beneficial effect on executive functioning in both training regimes, compared to the control intervention, with the largest effect in the combined cognitive-aerobic group. Secondary, intervention effects on cognitive functioning in other domains, physical functioning, physical activity levels, activities of daily living, frailty and quality of life are studied.

METHODS

The design is a single-blind, randomized controlled trial (RCT) with three groups: a combined cognitive-aerobic bicycle training (interactive cycling), a single aerobic bicycle training and a control intervention, which consists of stretching and toning exercises. Older adults with mild dementia follow a 12-week training program consisting of three training sessions of 30-40 min per week. The primary study outcome is objective executive functioning measured with a neuropsychological assessment. Secondary measures are objective cognitive functioning in other domains, physical functioning, physical activity levels, activities of daily living, frailty, mood and quality of life. The three groups are compared at baseline, after 6 and 12 weeks of training, and at 24-week follow-up.

DISCUSSION

This study will provide novel information on the effects of an interactive cycling training on executive function in older adults with mild dementia. Furthermore, since this study has both a combined cognitive-aerobic training and a single aerobic training group the effectiveness of the different components of the intervention can be identified. The results of this study may be used for physical and mental activity recommendations in older adults with dementia.

TRIAL REGISTRATION

The Netherlands National Trial Register NTR5581 . Registered 14 February 2016.

ApoE and SNAP-25 Polymorphisms Predict the Outcome of Multidimensional Stimulation Therapy Rehabilitation in Alzheimer’s Disease

Background. Alzheimer’s disease (AD) is a highly prevalent neurodegenerative disorder. Rate of decline and functional restoration in AD greatly depend on the capacity for neural plasticity within residual neural tissues; this is at least partially influenced by polymorphisms in genes that determine neural plasticity, including Apolipoprotein E4 ( ApoE4) and synaptosomal-associated protein of 25 kDa ( SNAP-25). Objective. We investigated whether correlations could be detected between polymorphisms of ApoE4 and SNAP-25 and the outcome of a multidimensional rehabilitative approach, based on cognitive stimulation, behavioral, and functional therapy (multidimensional stimulation therapy [MST]). Methods. Fifty-eight individuals with mild-to-moderate AD underwent MST for 10 weeks. Neuro-psychological functional and behavioral evaluations were performed blindly by a neuropsychologist at baseline and after 10 weeks of therapy using Mini-Mental State Examination (MMSE), Functional Living Skill Assessment (FLSA), and Neuropsychiatric Inventory (NPI) scales. Molecular genotyping of ApoE4 and SNAP-25 rs363050, rs363039, rs363043 was performed. Results were correlated with ΔMMSE, ΔNPI and ΔFLSA scores by multinomial logistic regression analysis. Results. Polymorphisms in both genes correlated with the outcome of MST for MMSE and NPI scores. Thus, higher overall MMSE scores after rehabilitation were detected in ApoE4 negative compared to ApoE4 positive patients, whereas the SNAP-25 rs363050(G) and rs363039(A) alleles correlated with significant improvements in behavioural parameters. Conclusions. Polymorphisms in genes known to modulate neural plasticity might predict the outcome of a multistructured rehabilitation protocol in patients with AD. These data, although needing confirmation on larger case studies, could help optimizing the clinical management of individuals with AD, for example defining a more intensive treatment in those subjects with a lower likelihood of success.

Biomarkers of Exposure to Polycyclic Aromatic Hydrocarbons and Cognitive Function among Elderly in the United States (National Health and Nutrition Examination Survey: 2001-2002)

Recent studies report a link between common environmental exposures, such as particulate matter air pollution and tobacco smoke, and decline in cognitive function. The purpose of this study was to assess the association between exposure to polycyclic aromatic hydrocarbons (PAHs), a selected group of chemicals present in particulate matter and tobacco smoke, and measures of cognitive performance among elderly in the general population. This cross-sectional analysis involved data from 454 individuals aged 60 years and older from the 2001–2002 National Health and Nutrition Examination Survey. The association between PAH exposures (as measured by urinary biomarkers) and cognitive function (digit symbol substitution test (DSST)) was assessed using multiple linear regression analyses. After adjusting for age, socio-economic status and diabetes we observed a negative association between urinary 1-hydroxypyrene, the gold standard of PAH exposure biomarkers, and DSST score. A one percent increase in urinary 1-hydroxypyrene resulted in approximately a 1.8 percent poorer performance on the digit symbol substitution test. Our findings are consistent with previous publications and further suggest that PAHs, at least in part may be responsible for the adverse cognitive effects linked to tobacco smoke and particulate matter air pollution.

Association Between Objectively Measured Physical Activity and Cognitive Function in Older Adults-The Reasons for Geographic and Racial Differences in Stroke Study

OBJECTIVES

To examine the relationship between objectively measured physical activity (PA) and cognitive function in white and black older adults.

DESIGN

Cross-sectional.

SETTING

REasons for Geographic and Racial Differences in Stroke (REGARDS) study.

PARTICIPANTS

Older adults who provided valid data from accelerometer and cognitive function tests (N = 7,098).

MEASUREMENTS

Accelerometers provided estimates of PA variables for 4 to 7 consecutive days. PA cut-points of 50 counts per minute (cpm) and 1,065 cpm were applied to differentiate between being sedentary and light PA and between light and moderate to vigorous PA (MVPA), respectively. Prevalence of cognitive impairment was defined using the Six-Item Screener (<4/6). Letter fluency, animal fluency, word list learning, and Montreal Cognitive Assessment (orientation and recall) were used to assess memory and executive function.

RESULTS

Of 7,098 participants (aged 70.1 ± 8.5, 54.2% female, 31.5% black), 359 (5.1%) had impaired cognition within ±12 months of PA measurement. The average proportion of time spent in MVPA (MVPA%) was 1.4 ± 1.9%. Participants in the highest quartile of MVPA% (~258.3 min/wk) were less likely to be cognitively impaired than those in the lowest quartile (odds ratio = 0.65, 95% confidence interval = 0.43-0.97). MVPA% was also significantly associated with executive function and memory z-scores (P < .001). Similar analyses of proportion of time spent in light PA (LPA%) and sedentary time (ST%) showed no significant associations with cognitive function.

CONCLUSION

Higher levels of objectively measured MVPA%, rather than LPA% or ST%, were associated with lower prevalence of cognitive impairment and better performance in memory and executive function in aging people. The amount of MVPA associated with lower prevalence of cognitive impairment is consistent with meeting PA guidelines.

Cardiorespiratory fitness and accelerated cognitive decline with aging

BACKGROUND

Growing evidence suggests that self-reported physical activity accounts for variability in cognitive function among older adults, and aerobic intervention may improve cognitive function in this population. However, much less is known about the longitudinal association between direct measures of cardiorespiratory fitness and cognitive function across the life span. The present study examined the prospective association between symptom-limited maximal oxygen consumption (VO2max) and longitudinal performance on a comprehensive neuropsychological battery.

METHODS

Up to 1,400 participants aged 19-94 years underwent initial VO2max assessment and completed subsequent tests of memory, attention, perceptuomotor speed, language, and executive function, in addition to cognitive screening measures, on up to six occasions (mean, M = 2; standard deviation, SD = 1) for up to 18 years (M = 7, SD = 3). Mixed-effects regression models were adjusted for demographic, biomedical, and behavioral confounders.

RESULTS

Analyses revealed significant longitudinal associations between baseline VO2max and trajectory of performance on multiple measures of verbal and visual memory, as well as on a cognitive screening test (all ps < .05). Individuals with lower VO2max demonstrated accelerated trajectories of cognitive decline over time.

CONCLUSIONS

Baseline cardiorespiratory fitness is related to longitudinal neuropsychological performance, and memory appears to be a particularly vulnerable domain. Evidence that aerobic fitness is associated with accelerated cognitive decline emphasizes the possible importance of behavioral interventions to optimize cognitive aging over time.

Multiple effects of physical activity on molecular and cognitive signs of brain aging: can exercise slow neurodegeneration and delay Alzheimer's disease?

Western countries are experiencing aging populations and increased longevity; thus, the incidence of dementia and Alzheimer's disease (AD) in these countries is projected to soar. In the absence of a therapeutic drug, non-pharmacological preventative approaches are being investigated. One of these approaches is regular participation in physical activity or exercise. This paper reviews studies that have explored the relationship between physical activity and cognitive function, cognitive decline, AD/dementia risk and AD-associated biomarkers and processes. There is now strong evidence that links regular physical activity or exercise to higher cognitive function, decreased cognitive decline and reduced risk of AD or dementia. Nevertheless, these associations require further investigation, more specifically with interventional studies that include long follow-up periods. In particular, relatively little is known about the underlying mechanism(s) of the associations between physical activity and AD neuropathology; clearly this is an area in need of further research, particularly in human populations. Although benefits of physical activity or exercise are clearly recognised, there is a need to clarify how much physical activity provides the greatest benefit and also whether people of different genotypes require tailored exercise regimes.