Arterial stiffness and age moderate the association between physical activity and global cognition in the older adults

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The Merck Sharp & Dohme Corp Program of the Faculty of Medicine of the Université de Montréal The Canadian Institutes of Health Research (CIHR)

Background

The growing concern on the impact of higher arterial stiffness on cognitive decline in older adults, leads to the question of whether non-pharmacological interventions like physical activity should be introduced to correct or diminish the progression of arterial stiffness.

Purpose

The goal of this study is to elaborate a model for arterial stiffness as a moderator for the physical activity and global cognition relationship in function of age. 

Methods

One hundred ten healthy older adults aged 60 to 75 years old (46 men and 64 women) were examined for arterial stiffness (carotid-femoral Pulse Wave Velocity (cf-PWV)), global cognition (Montreal Cognitive Assessment and Mini Mental State Examination) and self-reported physical activity (PACED diary). The double moderation analysis used PROCESS macro for SPSS, where physical activity was included as the independent variable (X), global cognition as the dependent variable (Y), arterial stiffness as moderator 1 (W), and age moderator 2 (Z). This study used a cf-PWV cutoff of 8.5 m/s to identify micro-structural damage in the brain related to arterial stiffness.

Results

Results found that the arterial stiffness x age interaction moderated the effect of physical activity on global cognition (β = -.89, SE = .42, p = .037) (Model: R2 = .15, p = .018). Physical activity had a positive effect on cognition in younger-older adults (aged 60 to 68.5 years) with high arterial stiffness i.e. cf-PWV > 8.5 m/s (β = .57, SE = .222, p = .011, 95% CI .133 to 1.014), and in older-older adults (aged 68.6 to 75 years) with low arterial stiffness i.e. cf-PWV < 8.5 m/s (β = .49, SE = .190, p = .010, 95% CI = .116 to .869). 

Conclusions

These results support targeted physical activity interventions based on age and degree of arterial stiffness, furthering the notion that even daily life physical activity could play an important role in older adults’ cognitive performances.

Physical activity on global cognition Conditional effects of physical activity on global cognition Moderators cf-PWV Age Effect SE p CI < 8.5 m/s < 68.5 years .171 .245 .487 -.315 to .657 < 8.5 m/s > = 68.5 years .574 .222 .011* .133 to 1.014 > = 8.5 m/s < 68.5 years .492 .190 .010* .116 to .868 > = 8.5 m/s > = 68.5 years .002 .180 .990 -.355 to .359 Physical activity conditional effects on global cognition at determined values of arterial stiffness and age. SE: Standard Error, CI: Confidence Interval, cf-PWV: carotid-femoral Pulse Wave Velocity, *p-value<.05.

Acute toxicity of locust insecticides to two indigenous invertebrates from Sahelian temporary ponds

During desert locust plagues large amounts of insecticides are used for control operations. Drift from these treatments and accidental overspraying may contaminate small surface waters such as temporary ponds. The present study describes methods for static acute toxicity tests with two abundant organisms that occur in temporary ponds in the African Sahel region: the fairy shrimp Streptocephalus sudanicus Daday (Branchiopoda, Anostraca, Streptocephalidae) and the backswimmer Anisops sardeus Herrich-Schåffer (Hemiptera, Notonectidae). The organisms were captured in the field and 48-h static toxicity tests were conducted in the laboratory. The assays were used to screen the toxicity of 11 formulated synthetic insecticides used in desert locust control and of spores of the mycopesticide Metarhizium anisopliae var. acridum. Most of the synthetic insecticides tested were highly toxic to both organisms (LC50 or EC50<1 mg/L). Exceptions were the toxicity of diflubenzuron to A. sardeus (moderately toxic: 1<LC50<10 mg/L), and that of fenitrothion (moderately toxic) and malathion (slightly toxic: 10<EC50<100 mg/L) to S. sudanicus. M. anisopliae var. acridum was moderately toxic to S. sudanicus and only slightly toxic to A. sardeus. EC50 values of the insecticides for S. sudanicus were not significantly correlated with L(E)C50 values for Daphnia magna collected from the literature. For A. sardeus a significant correlation with D. magna was found, but even in this data set the two species had widely differing sensitivities to some insecticides.

The Dielmo project: a longitudinal study of natural malaria infection and the mechanisms of protective immunity in a community living in a holoendemic area of Senegal

The Dielmo project, initiated in 1990, consisted of long-term investigations on host-parasite relationships and the mechanisms of protective immunity in the 247 residents of a Senegalese village in which malaria is holoendemic. Anopheles gambiae s.l. and An. funestus constituted more than 98% of 11,685 anophelines collected and were present all year round. Inoculation rates of Plasmodium falciparum, P. malariae, and P. ovale averaged respectively 0.51, 0.10, and 0.04 infective bites per person per night. During a four-month period of intensive parasitologic and clinical monitoring, Plasmodium falciparum, P. malariae, and P. ovale were observed in 72.0%, 21.1% and 6.0%, respectively, of the 8,539 thick smears examined. Individual longitudinal data revealed that 98.6% of the villagers harbored trophozoites of P. falciparum at least once during the period of the study. Infections by P. malariae and P. ovale were both observed in individuals of all age groups and their cumulative prevalences reached 50.5% and 40.3%, respectively. Malaria was responsible for 162 (60.9%) of 266 febrile episodes; 159 of these attacks were due to P. falciparum, three to P. ovale, and none to P. malariae. The incidence of malaria attacks was 40 times higher in children 0-4 years of age than in adults more than 40 years old. Our findings suggest that sterile immunity and clinical protection are never fully achieved in humans continuously exposed since birth to intense transmission.