Long Term Effect of Intensive Lifestyle Intervention on Cerebral Blood Flow.

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 -6.2% for ILI and -2.8% 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.