Low-density lipoprotein cholesterol and the risk of dementia with stroke

Context Next to Alzheimer disease; vascular dementia is the second most com mon form of dementia in the elderly, yet few specific risk factors have bee n identified. Objective To investigate the relationship of plasma lipids and lipoproteins to dementia with stroke. Design and Setting Prospective longitudinal community-based study over a 7- year period (1991-1998). Participants A total of 1111 nondemented participants (mean [SD] age, 75.0 [5.9] years) were followed up for an average of 2.1 years (range, 1-7.8 yea rs). Main Outcome Measure Incident dementia with stroke according to standardize d criteria, by baseline levels of total plasma cholesterol and triglyceride s, low-density lipoprotein (LDL)cholesterol, LDL levels corrected for lipop rotein(a), high-density lipoprotein cholesterol, lipoprotein(a), and apolip oprotein E genotype. Results Two hundred eighty-six (25.7%) of the 1111 subjects developed demen tia during follow-up; 61 (21.3%) were classified as having dementia with st roke and 225 (78.7%) as having probable Alzheimer disease. Levels of LDC ch olesterol were significantly associated with an increased risk of dementia with stroke. Compared with the lowest quartile, the highest quartile of LDL cholesterol was associated with an approximately 3-fold increase in risk o f dementia with stroke, adjusting for vascular risk factors and demographic variables (relative risk [RR], 3.1; 95% confidence interval [CI], 1.5-6.1) . Levels of LDL corrected for lipoprotein(a) were an even stronger predicto r of dementia with stroke in the adjusted multivariate analysis. Compared w ith the lowest quartile, the RR of dementia with stroke for the highest qua rtile of lipoprotein(a)-corrected LDL cholesterol was 4.1 (95% CI, 1.8-9.6) after adjusting for vascular factors and demographic variables. Lipid or l ipoprotein levels were not associated with the development of Alzheimer dis ease in-our cohort. Conclusions Elevated levels of LDL cholesterol were associated with the ris k of dementia with stroke in elderly patients. Further study is needed to d etermine whether treatment of elevated LDL cholesterol levels will reduce t he risk of dementia with stroke.