Insulin Resistance, Diabetes Mellitus and Low Cerebral Flow Reserve: Fuel to the Fire of the Dementia Epidemic

Body: Objective: Clarify insulin resistance (IR), diabetes mellitus (DM) and low cerebral flow reserve contributions to stroke (S) and dementia (D). Methods: Among 300 patients with cerebral ischemia symptoms, brain SPECT indices of basal metabolism (CMi), stimulated perfusion (CPi) and cerebral flow reserve (FRi = CPi – CMi and FRr = net stimulated/basal counts) used parabolic renal corrections. Same day scans for FRi and FRr correlations had background < 30%. Test Your Memory (TYM) dementia cutoff was < 41/50. Results: In 34 near normal patients age (51.8+-14.6) years, CMi was (57.3+-4.4)%, FRi (10.0+-2.5)% and TYM 47.6+-1.5. For 43 patients with FRr calculations: (20FRi) = 45.83(1.4FRr)+0.87 with r = 0.93. In 128 IR cases, age (52.4+-14.2) years, FRi was -(0.24+-6.71)%, TYM (43.4+-3.6), S 14.1%, D 16.5%; similarly, in 172 DM cases, age (56.5+-12.3) years, FRi was -(0.16+-9.0)%, TYM (43.8+-5.6), S 11.6%, D 19.7%, Age of S+D patients was (56.4+-12.2) years for IR cases and (57.9+-11.7) years for DM cases. For IR patients, males were a similar 25.8% (33/128) of the total and 26.3% (5/19) of D cases; however, males comprised more, 47.7% (82/172) of total and 63.3% (19/30) of D cases among DM patients. Conclusions: Total S and D are similar in IR and DM, hence IR (prevalence > > DM) likely contributes predominantly to overall cognitive impairment. Cost effective blood tests for amyloid fragments (Pesini P, 2012) and focused brain uptakes (Pretorius, 2005) may further clarify if DM predisposes even more to dementia in men than periemenopausal women.