The thing about Alzheimer’s is that it’s all relatives
Risk of developing the disease rises by almost 50% if your distant relatives had it, researchers have found
The risk of developing Alzheimer’s rises by almost 50% if people have distant relatives with the disease, a new study has shown.
Although it was known that having a parent with dementia raises the risk, new research shows that even distant cousins, great-uncles or great-grandparents with the condition should be treated as a warning sign.
Researchers made the link by studying more than 270,000 people from the Utah Population Database, which includes information about Utah pioneers and their descendants dating to the 1800s.
The database includes death records for all four grandparents and at least six of eight great-grandparents.
Researchers found that people with one first-degree relative (such as a parent) with Alzheimer’s disease had a 73% increased risk of developing the disease, meaning the risk would rise from 1.8 in 1,000 to 3.2 in 1,000.
People with two first-degree relatives were four times more likely to develop the disease; those with three were two-and-half more times likely, and those with four were nearly 15 times more likely to develop Alzheimer’s.
But those with only third-degree relatives, such as great-grandparents or great-uncles, also had a 43% greater risk of developing the disease even if close relatives had not been diagnosed.
“Family history is an important indicator of risk for Alzheimer’s disease, but most research focuses on dementia in immediate family members, so our study sought to look at the bigger family picture,” said study author Dr Lisa Cannon-Albright, of the University of Utah School of Medicine in Salt Lake City.
“We found that having a broader view of family history may help better predict risk. These results potentially could lead to better diagnoses and help patients and their families in making health-related decisions.
“People are increasingly seeking an estimate of their own genetic risk for Alzheimer’s disease. Our findings indicate the importance of clinicians taking a person’s full family history that extends beyond their immediate family members.”
About 850,000 people in Britain are suffering from dementia, and most have Alzheimer’s disease. The figure is expected to reach one million by 2025, but scientists are still unsure of the causes and no cure or long-term treatment has so far been discovered.
Experts now believe it may be impossible to reverse the brain cell damage which brings the debilitating effects of dementia, such as memory loss, and that stopping progression may be the only way to tackle the problem.
If so, catching the disease early, by screening people with a family history of dementia, is vital.
The figures also showed that people with one first-degree relative and one second-degree relative had a 21-times greater risk, or a chance of 37 in 1,000. Examples of this would be a parent and one grandparent with the disease, or a parent and one aunt or uncle.
“There are still many unknowns about why a person develops Alzheimer’s disease," added Cannon-Albright.
“A family history of the disease is not the only possible cause. There may be environmental causes, or both. There is still much more research needed before we can give people a more accurate prediction of their risk of the disease.”
The research was published in the journal Neurology.
– © The Daily Telegraph