Women diagnosed with osteoporosis may have a higher chance of carrying a gene linked to Alzheimer’s disease, according to new research.
Scientists found that APOE4 – the most common genetic risk factor for Alzheimer’s – can weaken bone quality in women, even when standard scans appear normal.
The study, carried out by researchers at the Buck Institute for Research on Ageing in California, US and UC San Francisco, suggests the gene may damage bone at a microscopic level long before any visible signs.
These changes can emerge as early as midlife and remain invisible to routine imaging tests used to assess bone strength.
The findings, published in the journal Advanced Science, suggest a link between Alzheimer’s risk and skeletal health – and could help pave the way for earlier detection of both conditions.
Doctors have long observed that people with Alzheimer’s suffer higher rates of bone fractures, while osteoporosis in women is known to be one of the earliest predictors of the disease.
Now scientists believe they may have uncovered why.
Researchers led by Dr Charles Schurman carried out a detailed analysis of proteins in aged mouse bone and found that tissue was unusually rich in molecules linked to neurological disease, including those associated with Alzheimer’s.
Women with osteoporosis may be more likely to carry a gene linked to Alzheimer’s disease, according to new research
In particular, long-lived bone cells known as osteocytes showed elevated levels of APOE, with levels twice as high in older female mice compared with younger or male animals.
Further experiments using genetically modified mice revealed that APOE4 had a strong and sex-specific impact on both bone and brain tissue.
The disruption at the protein level was even greater in bone than in the brain.
However, the bone structure itself appeared completely normal under scans.
Instead, the gene interfered with a key maintenance process inside bone cells, preventing them from repairing microscopic channels that keep bones strong and resilient.
Everyone experiences dementia differently. Use this checklist to help you make a note of your symptoms before you talk to your GP.
When this process breaks down, bones become more fragile – even if they look healthy on standard imaging.
‘What makes this finding so striking is that bone quality is being compromised at a molecular level that a standard bone scan simply will not catch,’ said Professor Birgit Schilling, a senior author of the study.
‘APOE4 is quietly disrupting the very cells responsible for keeping bone strong – and it is doing this specifically in females, which mirrors what we see with Alzheimer’s disease risk.’
These results suggest bone cells could potentially act as early biological warning signs of cognitive decline in women carrying APOE4.
‘We think targeting these cells may open a new front in preserving bone quality in this population,’ said Professor Lisa Ellerby, another senior author.
Experts say the findings highlight the need to view the body as an interconnected system rather than treating diseases in isolation.
Dementia – of which Alzheimer’s is the most common form – remains one of the UK’s biggest health challenges.
Around 900,000 people are currently living with the condition, a figure expected to rise to 1.6 million by 2040. It is already the leading cause of death, responsible for more than 74,000 deaths each year.
There is currently no cure, making early detection and prevention more urgent than ever.
