The long-term relation between physical activity and executive function in the Rotterdam Study.

BACKGROUND: Research on the association between physical inactivity and cognitive decline and dementia is dominated by studies with short-term follow-up, that might be biased by reverse causality. OBJECTIVE: Investigate the long-term association between physical activity, cognition, and the rate of age-associated cognitive decline. METHODS: We investigated the association between late-life physical activity and executive functioning and rate of decline of executive abilities during follow-up of up to 16 years, in 3553 participants of the prospective Rotterdam Study cohort. Measurement took place in 1997-1999, 2002-2004, 2009-2011, and 2014-2015. RESULTS: At baseline (age ± 72 years), higher levels of physical activity were associated with higher levels of executive functioning (adjusted mean difference = 0.03, 95% CI: 0.00 ; 0.06, p = 0.03). This difference remained intact up to 16 years of follow-up. The level of physical activity at baseline was unrelated to the rate of decline of executive abilities over time, in the whole group (adjusted mean difference in changetime*physical activity = 0.00, 95% CI: -0.00 ; 0.01, p = 0.31). However, stratification by APOE genotype showed that the accelerated decline of executive abilities observed in those with the ApoE-ε4 allele might be attenuated by higher levels of physical activity in late adulthood (ApoE-ε4 carriers: Btime*physical activity = 0.01, 95% CI: 0.00 ; 0.01, p = 0.03). CONCLUSION: Higher levels of physical activity in late adulthood are related to higher levels of executive functioning, up to 16 years of follow-up. Accelerated decline of executive abilities observed in those with the ApoE-ε4 allele might be mitigated by higher levels of physical activity.

The effects of a moderate physical activity intervention on physical fitness and cognition in healthy elderly with low levels of physical activity: a randomized controlled trial.

BACKGROUND: Increasing physical activity is one of the most promising and challenging interventions to delay or prevent cognitive decline and dementia. METHODS: We conducted a randomized controlled trial to assess the effects of a physical activity intervention, aimed at increasing step count, in elderly with low levels of physical activity on measures of strength, balance, aerobic capacity, and cognition. Participants were assigned to 9 months of exercise counseling or active control. RESULTS: The intention-to-treat analyses show that the intervention, compared to control, increases the level of physical activity, but has no significant effect on physical fitness and cognition. Those who increased their physical activity with 35% or more show significant improvements in aerobic capacity, gait speed, verbal memory, executive functioning, and global cognition, compared to those who did not achieve a 35% increase. LIMITATIONS: The number of participants that achieved the intended improvement was lower than expected. CONCLUSION: Responder analyses suggest an improvement of physical fitness and cognition in those who achieved an increase in physical activity of at least 35%. TRIAL REGISTRATION: The trial protocol is registered at the Dutch Trial Register NL5675, August 1, 2016.

Revisiting the Role of Insulin-Like Growth Factor-I Receptor Stimulating Activity and the Apolipoprotein E in Alzheimer's Disease.

Background: Alterations in insulin-like growth factor I (IGF-I) signaling have been associated with dementia and Alzheimer's disease (AD). Studies on the association between IGF-I levels and dementia risk have been inconclusive. We reported earlier that higher levels of IGF-I receptor stimulating activity are associated with a higher prevalence and incidence of dementia. Objective: In the present study, we test the robustness of the association between IGF-I receptor stimulating activity and dementia by extending the follow-up period to 16 years and investigate possible effect modification by apolipoprotein E (ApoE). Methods: At baseline, circulating IGF-I receptor stimulating activity was determined by the IGF-I kinase receptor activation (KIRA) assay in 1,014 elderly from the Rotterdam Study. Dementia was assessed from baseline (1997-1999) to follow-up in January 2015. Associations of IGF-I receptor stimulating activity and incident dementia were assessed with Cox proportional hazards models. Results: During 10,752 person-years of follow-up, 174 people developed dementia. In the extended follow-up we no longer observed a dose-response relationship between IGF-I receptor stimulating activity and risk of dementia [adjusted odds ratio 1.11; 95% confidence interval (CI) 0.97-1.28]. Interestingly, we found evidence of an interaction between ApoE-ε4 and tertiles of IGF-I receptor stimulating activity. IGF-I receptor stimulating activity in the median and top tertiles was related to increased dementia incidence in hetero- and homozygotes of the ApoE-ε4 allele, but did not show any association with dementia risk in people without the ApoE-ε4 allele (adjusted odds ratio medium vs. low IGF-I receptor stimulating activity in ApoE-ε4 carriers: 1.45; 95% CI 1.00-2.12). These findings suggest a threshold effect in ApoE-ε4 carriers. In line with the hypothesis that downregulation of IGF-I signaling is associated with increased dementia risk, ApoE-ε4 homozygotes without prevalent dementia displayed lower levels of IGF-I receptor stimulating activity than heterozygotes and non-carriers. Conclusion: The findings shed new light on the association between IGF-I signaling and the neuropathology of dementia and ask for replication in other cohorts, using measures of IGF-I receptor stimulating activity rather than total serum levels as putative markers of dementia risk.

Olfaction in the autism spectrum.

The autism spectrum (AS) is characterised by enhanced perception in vision and audition, described by the enhanced perceptual functioning (EPF) model. This model predicts enhanced low-level (discrimination of psychophysical dimensions), and mid- and high-level (pattern detection and identification) perception. The EPF model is here tested for olfaction by investigating olfactory function in autistic and Asperger participants. Experiment 1 targeted higher-order olfactory processing by assessing olfactory identification in nine Asperger, ten autistic, and eleven typically developed individuals. Experiment 2 focused on low-level olfactory processing; we assessed odour detection thresholds and odour discrimination in five Asperger, five autistic, and five typically developed males. Olfactory identification was impaired in autistic participants relative to control and Asperger participants. Typical performance in low-level olfactory processing suggests that neural mechanisms involved in the perceptual phenotype of AS do not affect structures implicated in olfactory processing. Reduced olfactory identification is limited to autistic participants who displayed speech delay and may be due to a reduced facility to use verbal labels. The apparent absence of enhanced olfactory perception of AS participants distinguishes the olfactory system from the other sensory modalities and might be caused by the absence of an obligatory thalamic relay.

Typicality and geographical origin markers of protected origin cheese from The Netherlands revealed by PTR-MS.

Volatile fingerprints of 30 cumin cheese samples of artisanal farmers' cheese of Leiden with EU Protected Designation of Origin (PDO) and 29 cumin cheese samples of varying commercial Dutch brands without PDO protection were used to develop authentication models. The headspace concentrations of the volatiles, as measured with high sensitivity proton-transfer mass spectrometry, were subsequently subjected to partial least-squares discriminant analysis (PLS-DA). Farmers' cheese of Leiden showed a distinct volatile profile with 27 and 9 out of the 60 predominant ions showing respectively significantly higher and lower concentrations in the headspace of the cheese in comparison to the other cumin cheeses. The PLS-DA prediction models developed classified in cross-validation 96% of the samples of PDO protected, artisanal farmers' cheese of Leiden correctly, against 100% of commercial cumin cheese samples. The characteristic volatile compounds were tentatively identified by PTR-time-of-flight-MS. A consumer test indicated differences in appreciation, overall flavor intensity, creaminess, and firmness between the two cheese groups. The consumers' appreciation of the cumin cheese tested was not influenced by the presence of a name label or PDO trademark.