Despite longstanding scientific evidence supporting a link between high cholesterol levels in middle-aged women and Alzheimer’s in later life, new Johns Hopkins research finds just the opposite.
In fact, the results show that when women’s cholesterol levels drop between middle age and old age, they are at 2.5 times greater risk for developing Alzheimer’s than those whose cholesterol remained steady or increased during this time.
“Our research refutes the notion that high cholesterol in midlife is a risk factor for Alzheimer’s disease, at least among women,” says Michelle M. Mielke, Ph.D., the study’s lead author and assistant professor of psychiatry at the Johns Hopkins University School of Medicine.
Although the study found no association between dementia risk and high middle-age cholesterol levels, Mielke still believes that people should keep an eye on their cholesterol since high levels are linked to cardiovascular and other diseases.
For the study, Mielke and her team analyzed data from the Prospective Population Study of Women—a health study which followed 1,462 Swedish women (ages 38 to 60) beginning in 1968. Four intermittent follow-ups were conducted throughout the decades, with the most recent examinations ending in 2001.
As part of the research, the participants received physical exams, heart tests, blood tests and chest x-rays. Body mass index (BMI), a measurement of weight-per-height, and blood pressure were taken as well. The women were also asked about their smoking habits, alcohol and medication use, medical history and education.
The group was assessed for dementia between 1968 and 2001. In 2001, 161 of the original participants had been diagnosed with Alzheimer’s or another form of dementia, but the youngest group was just reaching age 70.
The biggest known risk factor for neurodegenerative diseases is old age, despite advances in biomarker and other dementia research.
In fact, Mielke says that in later stages of life, women with slightly higher body mass index, higher levels of cholesterol and higher blood pressure seem to be healthier overall than those whose cholesterol, weight and blood pressure are too low.
But it remains undetermined if “too low” cholesterol, BMI and blood pressure are simply risk factors for dementia or if they could be signs that dementia is starting, Mielke says. For example, involuntary weight loss often precedes dementia, she says, but the exact cause is unknown.
The study is published online in the journal Neurology.
Source: Johns Hopkins Medicine