Cerebral blood flow and cerebrovascular resistance across the adult lifespan: A multimodality approach.

Cerebral blood flow (CBF) decreases across the adult lifespan; however, more studies are needed to understand the underlying mechanisms. This study measured CBF and cerebrovascular resistance (CVR) using a multimodality approach in 185 healthy adults (21-80 years). Color-coded duplex ultrasonography and phase-contrast MRI were used to measure CBF, CBF velocity, and vessel diameters of the internal carotid (ICA) and vertebral arteries (VA). MRI arterial spin labeling was used to measure brain perfusion. Transcranial Doppler was used to measure CBF velocity at the middle cerebral artery. Structural MRI was used to measure brain volume. CBF was presented as total blood flow (mL/min) and normalized CBF (nCBF, mL/100g/min). Mean arterial pressure was measured to calculate CVR. Age was associated with decreased CBF by ∼3.5 mL/min/year and nCBF by ∼0.19 mL/100g/min/year across the methods. CVR increased by ∼0.011 mmHg/mL/100g/min/year. Blood flow velocities in ICA and VA decreased with age ranging from 0.07-0.15 cm/s/year, while the vessel diameters remained similar among age groups. These findings suggest that age-related decreases in CBF can be attributed mainly to decreases in blood flow velocity in the large cerebral arteries and that increased CVR likely reflects the presence of cerebral vasoconstrictions in the small cerebral arterioles and/or capillaries.

Aerobic exercise training and neurocognitive function in cognitively normal older adults: A one-year randomized controlled trial.

BACKGROUND: Current evidence is inconsistent on the benefits of aerobic exercise training for preventing or attenuating age-related cognitive decline in older adults. OBJECTIVE: To investigate the effects of a 1-year progressive, moderate-to-high intensity aerobic exercise intervention on cognitive function, brain volume, and cortical thickness in sedentary but otherwise healthy older adults. METHODS: We randomized 73 older adults to a 1-year aerobic exercise or stretching-and-toning (active control) program. The primary outcome was a cognitive composite score calculated from eight neuropsychological tests encompassing inductive reasoning, long-term and working memory, executive function, and processing speed. Secondary outcomes were brain volume and cortical thickness assessed by MRI, and cardiorespiratory fitness measured by peak oxygen uptake (VO2 ). RESULTS: One-year aerobic exercise increased peak VO2 by ∼10% (p < 0.001) while it did not change with stretching (p = 0.241). Cognitive composite scores increased in both the aerobic and stretching groups (p < 0.001 for time effect), although no group difference was observed. Total brain volume (p < 0.001) and mean cortical thickness (p = 0.001) decreased in both groups over time, while the reduction in hippocampal volume was smaller in the stretching group compared with the aerobic group (p = 0.040 for interaction). Across all participants, improvement in peak VO2 was positively correlated with increases in cognitive composite score (r = 0.282, p = 0.042) and regional cortical thickness at the inferior parietal lobe (p = 0.016). CONCLUSIONS: One-year aerobic exercise and stretching interventions improved cognitive performance but did not prevent age-related brain volume loss in sedentary healthy older adults. Cardiorespiratory fitness gain was positively correlated with cognitive performance and regional cortical thickness.

Factors associated with poor asthma control in the outpatient clinic setting.

BACKGROUND/OBJECTIVES: The goal of the study was to assess asthma control using asthma control test (ACT) and to explore the factors that effects asthma control among participants with bronchial asthma in the outpatient clinic setting. METHODS: This cross-sectional descriptive study was conducted in the outpatient primary care clinic at King Abdulaziz Medical City in Riyadh. Adult patients who were diagnosed with bronchial asthma by their primary treating physician were recruited over a 6-month period. Patients completed the ACT and questionnaires, which identified factors that affect asthma control. RESULTS: Four hundred asthmatic patients (n = 400) were enrolled, and 70% of these patients were women. Fifty-four percent of patients inappropriately used the inhaler device. The estimated prevalence of uncontrolled asthma at the time of the study was 39.8%. Inappropriate device use by the patient was more frequently associated with uncontrolled asthma (P-value = 0.001). Active smoking (P-value = 0.007), passive smoking (P-value = 0.019), unsealed mattress (P-value = 0.030), and workplace triggers (P-value = 0.036) were also associated with uncontrolled asthma. However, the extent of asthma control did not appear to be related to the existence of regular follow-ups, bedroom carpets, outpatient clinic visits, age, body mass index (BMI), or duration of asthma. CONCLUSIONS: The present study identified a high prevalence of uncontrolled asthma in the primary outpatient clinic setting and common risk factors that may contribute to poor asthma control.