Long Term Effect of Intensive Lifestyle Intervention on Cerebral Blood Flow

Abstract

OBJECTIVES:To determine whether long-term behavioral intervention targeting weight loss through increased physical activity and reduced caloric intake would alter cerebral blood flow (CBF) in individuals with type 2 diabetes mellitus. DESIGN: Postrandomization assessment of CBF. SETTING: Action for Health in Diabetes multicenter randomized controlled clinical trial. PARTICIPANTS: Individuals with type 2 diabetes mellitus who were overweight or obese and aged 45 to 76 (N = 310). INTERVENTIONS: A multidomain intensive lifestyle intervention (ILI) to induce weight loss and increase physical activity for 8 to 11 years or diabetes support and education (DSE), a control condition. MEASUREMENTS: Participants underwent cognitive assessment and standardized brain magnetic resonance imaging (MRI) (3.0 Tesla) to assess CBF an average of 10.4 years after randomization. RESULTS: Weight changes from baseline to time of MRI averaged À6.2% for ILI and À2.8% for DSE (P < .001), and increases in self-reported moderate or intense physical activity averaged 444.3 kcal/wk for ILI and 114.8 kcal/wk for DSE (P = .03). Overall mean CBF was 6% greater for ILI than DSE (P = .04), with the largest mean differences between ILI and DSE in the limbic region (3.39 mL/100 g per minute, 95% confidence interval (CI) = 0.07-6.70 mL/ 100 g per minute) and occipital lobes (3.52 mL/100 g per minute, 95% CI = 0.20-6.84 mL/100 g per minute). In ILI, greater CBF was associated with greater decreases in weight and greater increases in physical activity. The relationship between CBF and scores on a composite measure of cognitive function varied between intervention groups (P = .02). CONCLUSIONS: Long-term weight loss intervention in overweight and obese adults with type 2 diabetes mellitus is associated with greater CBF. J Am Geriatr Soc 66:120-126, 2018.

Aerobic Exercise Training Improves Cerebral Blood Flow and Executive Function: A Randomized, Controlled Cross-Over Trial in Sedentary Older Men

“…A healthy lifestyle, consisting of a healthy diet combined with increased physical activity has been proposed to protect against cognitive impairment by improving CBF (Gorelick et al, 2011). In fact, CBF was improved following a healthy lifestyle intervention and associated with higher cognitive performance in overweight or obese participants aged between 45 and 76 years (Espeland et al, 2018). Furthermore, cross-sectional studies have observed that lower aerobic fitness in sedentary older individuals was associated with a reduced CBF and decreased cognitive performance (Tarumi and Zhang, 2017).…”

Reduced parenchymal cerebral blood flow is associated with greater progression of brain atrophy: The SMART-MR study

“…Nonetheless, the significant longitudinal relationship between pCBF and BPF in the present study supports a role of cerebral blood flow in the process of neurodegeneration and, from a clinical perspective, strengthens the notion that cerebral blood flow could be a potential target for future prevention strategies of brain atrophy. [17][18][19] In the present study, we chose a bidirectional modelling approach between pCBF and BPF for the following reasons. First, although experimental studies using animal models suggest that reduced cerebral blood flow may be a risk factor for brain tissue loss, 37 some studies hypothesized that smaller brain volumes may lead to reduced metabolic demand, which in turn may lead to a greater decrease in cerebral blood flow over time.…”

Pathways of Prevention: A Scoping Review of Dietary and Exercise Interventions for Neurocognition

“…For example, ILI participants demonstrated a 28% lower white matter hyperintensity volume compared to DSE participants, as well as a 9% lower ventricle volume [221]. Similarly, cerebral blood flow increased among the ILI participants relative to DSE [244]. Most interestingly, these improvements did not associate with changes in neurocognition, and changes in CBF actually demonstrated a divergence in their association with neurocognition between treatment groups, with improved CBF associating positively with neurocognition among ILI participants, but not in DSE participants.…”

“…Results of the ILI on neuroimaging markers revealed a different pattern of findings. Among a subset of participants who underwent structural brain imaging or cerebral perfusion scans, ILI generally demonstrated improvements compared to DSE [221,244]. For example, ILI participants demonstrated a 28% lower white matter hyperintensity volume compared to DSE participants, as well as a 9% lower ventricle volume [221].…”

“…Unfortunately, contemporary causal inference approaches have demonstrated this is often not the case for several reasons: 1) the mediating variable is not normally distributed, 2) the mediator interacts with the treatment variable to differentially modify outcomes (treatment-exposure interaction), or 3) the association underlying changes in the mediator and changes in outcome is confounded by a related but unmeasured confounder [354,370]. One has to look no further than the LOOK-AHEAD trial to find evidence for a treatment-exposure interaction, with the effects of weight loss on neurocognition varying across participants [242], as well as the association between improved CBF and neurocognition showing differential associations across participants [244]. These findings suggest that unmeasured factors likely impacted the mechanistic function of weight loss, perhaps with more metabolically compromised participants experiencing destabilized central metabolism in the presence of weight reduction.…”