The Risk of a High Cholesterol Level in Middle Age

Even a slightly raised cholesterol level in mid-life may increase the likelihood that someone develops dementia in later life, according to a study published in the journal Dementia & Geriatric Cognitive Disorders.

Data for the study came from the Kaiser Permanente Northern California Medical Group (a healthcare delivery organization). People aged 40 to 45 were recruited between 1964 and 1973; 9,844 of them were followed for up to 40 years. During this time 598 of them developed Alzheimer’s disease or vascular dementia, determined from medical records between 1994 and 2007.

Total cholesterol levels of 220 mg/dL or above in samples taken at enrollment raised the risk of subsequent Alzheimer’s disease in a “dose-dependent” fashion. (Data on low-density lipoprotein [LDL] cholesterol levels were not available at the time of sampling.)

After adjustment for variations in age, gender, education, race/ethnicity, midlife BMI, diabetes, high blood pressure, and late-life stroke, the following hazard ratios or odds were obtained for Alzheimer’s, using the “below 198 mg/dL” risk as the 1.0, or the reference level:

198–220 mg/dL  1.25

221–248 mg/dL  1.31

249–500 mg/dL  1.58

Vascular dementia risks didn’t display this “dose-response” effect with cholesterol levels, although the 221-248 mg/dL group had a high hazard ratio – 1.50.

This study didn’t explore whether controlling high cholesterol levels with drugs or a healthy lifestyle could reduce the risk of developing Alzheimer’s. However, other studies have suggested that this is the case. Most important is the recognition of the long time-lag between the recorded raised cholesterol level and the onset of the disease. If you have a high cholesterol in your forties, get busy; you can probably reach normal values with a little effort, and spare yourself an increased risk of Alzheimer’s disease or vascular dementia.