Association of blood pressure and genetic background with white matter lesions in patients with mild cognitive impairment.

Background White matter lesions WMLs may contribute to cognitive deficits in patients with mild cognitive impairment MCI but their pathogenesis is complex Fluctuations of blood pressure BP over 24 hours and genetic predisposition to develop vascular damage have been implicated Methods In 63 MCI patients 65 years old or older BP was measured both clinically and with ambulatory BP monitoring Patients were classified in two groups no very mild n 34 and mild to severe n 29 WMLs based on a visual scale on magnetic resonance mean age 71 8 4 7 vs 74 6 5 1 and female gender 53 vs 66 respectively The volume of WMLs was measured by a semi automatic method separately for periventricular caps and rim periventricular confluent subcortical punctate and subcortical confluent Polymorphisms of cystatin C CST3 and cholesterol 24 hydroxylase CYP46 genes putative risk factors for cerebrovascular disease were determined Results The prevalence of cerebrovascular risk factors was similar in the two MCI groups of different WML severity as well as clinic and ambulatory BP In patients with mild to severe but not in those with no very mild WMLs the volume of periventricular confluent WMLs increased with increasing daytime systolic BP regression coefficient 47 95 confidence interval CI 13 to 71 vs 02 95 CI 32 to 36 p 003 for the difference between slopes The volume of other WML subtypes was not associated with ambulatory BP Participants carrying both CST3 B and CYP46 T alleles were overrepresented in the MCI group with mild to severe WMLs 43 vs 17 p 03 Conclusions BP and gene putative risk factors for cerebrovascular disease are differentially associated with WMLs in two MCI groups of different WML severity WMLs might develop for the convergence of innate with acquired factors