Genes vs. lifestyle: Study ‘undermines fatalistic view of dementia’

A new study investigates the effect of leading a healthful lifestyle on people who have a genetic predisposition to developing dementia.
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Leading a healthful lifestyle can offset the genetic risk of dementia, according to a new study.

Elżbieta Kuźma, Ph.D., and David Llewellyn, Ph.D., from the University of Exeter Medical School in the United Kingdom, are the joint lead authors of the new research, which appears in the journal JAMA.

Llewellyn, Kuźma, and colleagues also presented their findings at the Alzheimer’s Association International Conference 2019, which took place in Los Angeles, CA.

In their paper, the authors explain that while scientists know that genes and lifestyle both significantly affect Alzheimer’s risk and the likelihood of other types of dementia, they do not yet know the extent to which making healthful lifestyle choices can offset the genetic risk.

For instance, research has shown that the E4 variant of the gene that encodes the apolipoprotein E raises the risk by threefold if a person inherits one copy and up to 15 times if they have two copies of the gene.

However, a significant body of research also points to the fact that people who do not smoke, are physically active, only consume alcohol in moderation, and follow a healthful diet are at a lower risk of dementia.

So, to find out how lifestyle can influence genetic risk, Llewellyn and colleagues examined data on “196,383 participants of European ancestry aged at least 60 years” who did not have dementia at the start of the study.

Assessing lifestyle and genetic risk

The participants had enrolled in the U.K. Biobank study in 2006–2010, and researchers followed them clinically until 2016–2017.

Llewellyn and team calculated the polygenic risk score for each person. The score “captured an individual’s load of common genetic variants associated with Alzheimer’s disease and dementia risk.”