It’s no secret that Alzheimer’s has a genetic component, with many sufferers having a parent who also had the disease. But how is our risk of Alzheimer’s affected by more distant family members? Well, according to a new study published in Neurology, having relatives like great aunts and uncles, cousins, and great-grandparents with Alzheimer’s can also increase our risk.
Alzheimer’s is a neurodegenerative condition that mainly impacts memory, although it can also affect communication, mood, and even our mobility. It tends to appear in old age and at present, about 5.8 million Americans over the age of 65 are living with the disease. Unfortunately, there’s currently no cure.
Researchers at the University of Utah analyzed data from more than 270,800 people who were part of the Utah Population Database. They looked at whether any of their family members had ever suffered from Alzheimer's disease.
"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," study author Lisa A. Cannon-Albright said in a statement.
So, as well as focusing on first-degree family members (parents and siblings), the team also looked at second and third-degree relatives. Second-degree family members include grandparents, aunts and uncles, and half-siblings. Meanwhile, third-degree relatives include first cousins, great-grandparents, and great aunts and uncles.
The results showed that having a more distant relative with Alzheimer’s can increase our risk of developing the disease.
Having one first-degree relative with Alzheimer’s was found to increase risk by 73 percent, while those with two affected first-degree relatives were four times more likely to suffer from the disease. People with four first-degree relatives with Alzheimer’s were nearly 15 times more likely to develop the condition.
When it came to more distant relatives, those with one first-degree and one second-degree family member with Alzheimer’s were 21 times more likely to develop the disease, while those with three affected third-degree relatives had a 43 percent higher risk.
"We found that having a broader view of family history may help better predict risk,” explained Cannon-Albright. “These results potentially could lead to better diagnoses and help patients and their families in making health-related decisions.”
However, having relatives with Alzheimer’s in no way means you’re definitely going to develop the disease. There are many other factors involved in the onset of Alzheimer’s, such as obesity, high blood pressure, diet, and smoking, and we still have a lot to learn about why some people get Alzheimer’s and others don’t.
"There are still many unknowns about why a person develops Alzheimer's disease," said 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."