Researchers from the US have reported findings from a study of 399,979 people with high cholesterol aged over 65 showing that statin use is associated with a reduced incidence of Alzheimer’s, but that this varies between sexes and ethnic groups. The results are published today in JAMA Neurology.
The researchers used data collected by Medicare, a national health insurance provider in the US. The study included 399,979 people aged 65 or over in January 2006, who used statins to treat their high cholesterol but did not have an Alzheimer’s diagnosis before 2009. Participants were placed into different groups based on their sex and ethnicity, with 310,240 non-Hispanic white people, 32,658 Hispanic people, 32,278 non-Hispanic black people, and 24,803 people of Asian, native American or unknown race/ethnicity involved in the study.
In the total study group, between 2009 and 2013, 1.72% of women an 1.32% of men were diagnosed with Alzheimer’s disease annually. The incidence of Alzheimer’s was higher among Hispanic (2.29%) and black women (2.11%) than white women (1.64%), with white men having the lowest incidence of Alzheimer’s (1.23%). The researchers found that statin use was higher in white people, with 282 and 284 days per year of statin use in white women and men, respectively. This compared with 254 days per year for black men and Hispanic men and women, and 255 days per year for black women.
Overall, the researchers observed a lower proportion of new diagnoses of Alzheimer’s disease in statin users compared to non-users, with those having regular statin prescriptions between 2006-2008 showing a lower incidence of the disease than those who took statins more infrequently.
The researchers then looked at how different statins were associated with Alzheimer’s risk, as simvastatin and atorvastatin work differently to pravastatin and rosuvastatin, and are known to enter the brain more readily. They found that simvastatin was associated with a lower Alzheimer’s risk in white, Hispanic and black women, and that high exposure to simvastatin was linked with a reduced Alzheimer’s risk in white and Hispanic men. Pravastatin and rosuvastatin were only associated with reduced Alzheimer’s risk for white women. No statins were associated with a reduction in Alzheimer’s risk for black men.
Dr Rosa Sancho, Head of Research at Alzheimer’s Research UK, said:
“Although this study highlights a link between statin use and a lower risk of Alzheimer’s, we can’t say from this research that statins can prevent the disease. These types of studies identify important trends, but cannot allow researchers to conclude a causal relationship between statin use and Alzheimer’s risk. This research differs from previous studies in the general population, as it focused on people who already have raised cholesterol, which is itself a known risk factor for Alzheimer’s disease.
“The reasons why sex and ethnicity may influence trends in Alzheimer’s risk are very important to understand, as these factors must be taken into consideration in studies of Alzheimer’s risk. Until there is firm evidence from clinical trials, we would not recommend people take statins for the purpose of preventing Alzheimer’s disease. Cardiovascular risk factors can be associated with poor brain health, so keeping cholesterol in check is important for maintaining a healthy brain as we age. Other ways to keep the brain healthy include regular exercise, eating a balanced diet, maintaining a healthy weight, not smoking and controlling high blood pressure. Those concerned about their cholesterol should talk to their doctor.”