People with low levels of lipoprotein cholesterol with low density (LDL-C) in their blood have a lower risk of dementia, including a lower risk of dementia from Alzheimer’s, shows a study published online today in theJournal of Neurology Neurosurgery & Psychiatry.
The use of statins conveyed an extra protective effect for people with low LDL-C, in particular those with blood mirrors less than 1.8 mmol/l (<70 mg/dl), which reduces their risk of dementia even further.
However, reducing LDL-C to very low levels below 0.8 mmol/l (<30 mg/dl) did not further reduce the risk of dementia.
The benefits of low LDL-C levels to protect against cardiovascular events are well recognized, but the relationship between LDL-C levels and dementia has been less clear, in particular the closure of LDL-C, including no further advantage for reducing the risk of cognitive decline.
To tackle this, the authors have gathered access to data by 11 university hospitals about outpatient adults without previous diagnosis of dementia, for at least 180 days after testing LDL-C. They identified 192,213 people with LDL-C levels less than 1.8 mmol/l (<70 mg/dl) en 379,006 patiënten met LDL-C-niveaus van meer dan 3,4 mmol/L (> 130 mg/dl), and matched individuals in each group in 108,980 matched couples.
Analysis of subsequent diagnoses of dementia showed that LDL-C levels under 1.8 mmol/l (<70 mg/dl) geassocieerd waren met een vermindering van 26% in het risico op dementie door alle oorzaken en een reductie van 28% in het risico op de ziekte van Alzheimer, vergeleken met LDL-C-niveaus boven 3,4 mmol/L (> 130mg/dl).
The protective effect against cognitive decline was reduced at lower LDL-C levels and eventually disappeared completely. At LDL-C levels under 1.4 mmol/l (<55 mg/dl) was er een 18% risicoreductie voor zowel alle dementie als Alzheimer-ziektegerelateerde dementie vergeleken met LDL-C-niveaus boven 3,4 mmol/L (> 130 mg/dl), and when LDL-C level below 0.8 mmol/l (<30 mg/dl) has disappeared.
STATINE BUSHING Gifted extra protection against dementia in the presence of low LDL-C levels. Of the people with LDL-C levels under 1.8 mmol/l (<70 mg/dl), statin use was associated with a reduction of 13% in all risk of dementia and a decrease in the risk of 12% in the risk of dementia of Alzheimer's compared to non-users.
This is an observational study and as such, no strong conclusions can be drawn about cause and effect. The authors also acknowledge that the study has some limitations, including the potential for non-measured confusing factors due to the retrospective design, possibly under reporting of dementia cases due to variations in diagnostic accuracy between hospitals, and the focus on baseline LDL-C levels when lipid profiles could change over time.
Nevertheless, the authors conclude: “Low LDL-C levels (<70 mg/dl (<1.8 mmol/l)) are considerably associated with a reduced risk of dementia, including the dementia of Alzheimer's disease, where statin therapy offers additional protective effects."
They add: “These findings underline the crucial role of managing LDL-C when reducing the risk of dementia.”