Healthy Midlife Heart Lowers Dementia Risk
Protecting the Heart in Middle Age Helps the Brain Decades Later
Jan. 24, 2005 -- The same things that burden a middle-aged heart can push the brain towards dementia decades later. That's all the more reason to quit cigarettes and get cholesterol, diabetes, and blood pressure under control as soon as possible.
Diabetes, high blood pressure, high cholesterol, and smoking are all well-known risk factors for heart disease. They may also boost the risk for dementia later in life.
Middle-aged people with high blood pressure, high cholesterol, and diabetes are 20%-40% more likely to develop dementia in old age, a new study shows. Kaiser Permanente's Rachel Whitmer, PhD, and colleagues report their findings in the January issue of Neurology.
A Generation's Evidence
The researchers followed more than 8,800 participants for an average of 30 years. They wanted to determine the predictive value of cardiovascular risk factors on the development of dementia.
All were Kaiser Permanente members in Northern California. Most (57%) were men.
The study required a little time traveling.
First, the researchers checked participants' medical records from 1964-1973. Lyndon B. Johnson and then Richard M. Nixon were America's presidents. Cable TV, cell phones, and home computers were science fiction, to most people.
At the time, the study's participants were about 42 years old.
Though fairly young, some participants already had health problems. Sixty percent said they had smoked. In addition a few had midlife cardiovascular risk factors: 11% had diabetes, 32% had high cholesterol, and 19% had high blood pressure.
Fast forward 27 years, to between 1994 and 2003. By then, 8% (721) had been diagnosed with dementia. On average, dementia was diagnosed at age 74.
Shared Risk Factors for Dementia
Dementia usually affects older people; the risks of dementia increase with age. But gathering years weren't the only risk factor. Health problems from midlife also had an impact.
Having diabetes had the biggest effect. Middle-aged people with diabetes were 46% more likely to be diagnosed with dementia in old age. A large number of studies have shown that having diabetes in late life increases the risk of dementia, the researchers note.
High cholesterol was also a problem. People with high total cholesterol levels in their midlife were 42% more likely to be diagnosed with dementia as seniors.
Smoking was another danger. A late-life dementia diagnosis was 26% more likely for people who said they had ever smoked by middle age.
Combined Effects Even Worse
Compared with someone without those risk factors during midlife, dementia later in life was 27% more likely for someone with just one of those conditions. Those with more strikes against them were even more vulnerable.
Having two of the four midlife risk factors made a dementia diagnosis 70% more likely later in life. That could be any combination of the risk factors, such as smokers with high cholesterol, or diabetes patients with high blood pressure.
Middle-aged participants with three of four heart disease risk factors were 2.3 times as likely to get a dementia diagnosis later on. Those with all four risk factors at midlife -- smokers with diabetes, high cholesterol, and high blood pressure -- were 2.37 times more likely to be diagnosed with dementia later in life.
Help the Heart, Help the Brain
What's good for the heart might also benefit the brain. "Earlier treatment of heart disease may lower risk of dementia," say the researchers, in a news release.
That knowledge may help future generations save their brains and hearts alike. More studies are needed to understand exactly how heart hazards hurt the brain and what helps most, they say.