Associations of microalbuminuria with brain atrophy and white matter hyperintensities in hypertensive sibships.
BACKGROUND
Because of similarities between brain and kidney microvascular disease, there may be a relationship between measures of renal microvascular disease and brain structural changes in middle aged or elderly individuals.


OBJECTIVE
To determine whether the urine albumin/creatinine ratio (UACR), a measure of renal microvascular disease, is associated with brain atrophy and white matter hyperintensities.


METHODS
As part of a larger study of the genetics of hypertension, we performed brain imaging and assessed microalbuminuria and other vascular risk factors including diabetes, hypertension, hyperlipidemia and hyperhomocysteinemia in 1253 individuals from hypertensive sibships (age mean 63.8 years, range 50 to 91; 65% women; 49% African-American; 78% hypertensive). Semi-automated quantitative measurements of brain atrophy (BA) ventricular volume, and white matter hyperintensities (WMH) were carried out on the brain MR scans.


RESULTS
In logistic regression models, elevated UACR was associated with greater BA (odds ratio (OR)=1.70 (95% CI 1.14, 2.54) and burden of WMH (OR=2.06 (95% CI 1.37, 3.10) after controlling for demographic factors, blood glucose, hypertension severity, duration of smoking and serum homocysteine. In contrast to elevated UACR, the associations with elevated creatinine or reduced glomerular filtration rate and WMH were not significant in the fully adjusted models.


CONCLUSIONS
In this cohort with an overrepresentation of hypertensives, elevated UACR was independently associated with both brain atrophy and white matter hyperintensities. Brain volume loss and WMH burden might represent expressions of microvascular disease that share common mechanisms with nephrosclerosis.
Knopman
David S
DS
Division of Behavioral Neurology, Department of Neurology, Mayo Clinic College of Medicine, Rochester, MN 55905, United States. knopman@mayo.edu
Mosley
Thomas H
TH
Bailey
Kent R
KR
Jack
Clifford R
CR
Schwartz
Gary L
GL
Turner
Stephen T
ST
D001741:Black or African American; D000368:Aged; D000369:Aged, 80 and over; D000419:Albuminuria / Q000150:complications* / Q000473:pathology*; D001284:Atrophy / Q000150:complications; D001921:Brain / Q000473:pathology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000473:pathology*; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D044465:White People