We compared serum levels of coenzyme Q(10) and the coenzyme Q(10)/cholester
ol ratio in 44 patients with Alzheimer's disease (AD), 17 patients with vas
cular dementia (VD), and 21 matched controls. The mean serum coenzyme Q(10)
and cholesterol levels and the coenzyme Q(10)/cholesterol ratio of patient
s with AD or VD did not differ significantly from those of controls. Coenzy
me Q(10) levels and coenzyme Q(10)/cholesterol ratio of AD or VD patients w
ere not correlated with age, age at onset, duration of the disease or score
s of the MiniMental State Examination. These results suggest that these val
ues are not related with the risk for AD or VD.