The Alzheimer’s Association
Alzheimer’s & Dementia : The Journal of the Alzheimer’s Association
Midlife insulin resistance (IR) has previously been shown to be associated with lower cerebral blood flow (CBF), and is a potentially modifiable risk factor for dementia. The Blood Flow Improvement Trial (BFiT), NCT03117829 , tested a 12 week carbohydrate restricted diet (CRD) and exercise behavioral intervention to reverse IR, and aimed to 1) determine the extent to which improving or normalizing glucose homeostasis improves CBF and cognitive function in individuals with IR, 2) determine whether participants continue to maintain improved or normalized glycemic control for 6 months, and 3) determine changes in the human metabolome as individuals improve or normalize IR and glucose homeostasis through diet and exercise.
Participants were recruited from the Wisconsin Alzheimer’s Disease Research Center and screened for metabolic risk factor eligibility based on the criteria shown in Table 1. The design involved a 12 week diet and exercise intervention focused on self‐monitoring to promote adherence. Exercise was conducted in a supervised group setting 3 days/week for 50 minutes and participants were instructed to exercise on their own an additional 2 days/week. Participants followed a CRD and monitored their own blood glucose with the goal of achieving and maintaining fasting blood glucose/dL. Participants underwent baseline, 12 week, and 6 month procedures including urine and blood labs/metabolomics, cognitive testing, fitness testing, and blood flow imaging via MRI (Table 2).
The enrollment goal was 40 participants. 118 individuals were screened for eligibility, and 72.5% of the target enrollment was met; of those participants, nearly 80% completed the 12 week intervention. Of the 23 participants that completed the intervention, mean attendance was 70% for supervised exercise sessions and 81% for weekly behavioral coaching sessions. Figure 1 summarizes screening, enrollment, and procedure completion.
IR may be a modifiable risk factor for dementia. The BFiT pilot trial was designed to test the feasibility of exercise and CRD to reduce IR and improve brain blood flow in middle‐aged adults. Reasonable enrollment and completion N were achieved. Future analysis will center on barriers to enrollment and adherence, as well as analysis of the primary and secondary outcome measures.
MacAlpine, Maiya F.; Heston, Margo B.; Gaitán, Julian M.; Okonkwo, Ozioma C.; Bendlin, Barbara B.; Gretebeck, Kimberlee A.; and Gretebeck, Randall J., "Blood Flow Improvement Trial: Design and Enrollment Developing Topics" (2020). College of Nursing Faculty Research and Publications. 879.