A study of nearly 58,000 patients found that high-potency statins had the strongest protective effects against dementia.
Researchers studied if statin use was linked to new diagnoses of dementia. They used a random sample of one million patients covered by Taiwan's National Health Insurance.
They identified 57,669 patients aged over 65 who had no history of dementia in 1997 and 1998.
The analysis included pre-senile and senile dementia, but excluded vascular dementia.
There were 5516 new diagnoses of dementia during around 4.5 years of follow-up.
The remaining 52,153 patients aged over 65 formed the control group.
Dr Tin-Tse Lin, who presented the findings at the European Society of Cardiology Congress in Amsterdam, said: "The adjusted risks for dementia were significantly inversely associated with increased total or daily equivalent statin dosage."