Efforts to find treatments that slow or prevent Alzheimer’s disease are making good progress, but the complexities of tackling the illness are making it difficult to estimate what impact they will have on future mortality rates.
A new report by reinsurer RGA on the current state of play in Alzheimer’s research stated that a combination of disease-modifying therapies and better understanding of the causes and progression of Alzheimer’s “point to a future that is cautiously but meaningfully brighter”.
Nevertheless, its authors said that the likelihood of these developments substantially improving life expectancy was low because other more deadly diseases are still extant.
“Most experts agree that disease-modifying treatments for Alzheimer’s disease slow clinical progression but do not generate large reductions in all-cause mortality rates,” co-author Richard Russell, Vice President, Biometric Research, Global R&D at RGA told Longevity and Mortality Investor.
“However, reductions in Alzheimer’s‑specific mortality do not translate one‑for‑one into reductions in all-cause mortality. All-cause mortality rates must reflect individuals’ exposure to cardiovascular disease, cancer, infections, frailty‑related concerns and other age‑associated risks.”
Scientists estimate that the disease, the single most prevalent form of dementia, afflicts 35 million to 45 million people worldwide and is set to increase threefold in the next 25 years, the report said.
Ironically, the advances that are helping doctors better tackle the disease are also making it harder for actuaries to predict future patterns of affliction and how that might affect overall life expectancy.
Published last month and entitled Alzheimer’s Update: Progress against a progressive disease, RGA’s report stated that frequent changes in treatments, diagnostics, detection rates and factors including reporting bias make “the interpretation and modelling of trends far from straightforward”.
“Interpreting Alzheimer’s trends is complicated by the fact that historical patterns reflect changes in diagnostic practices, data availability and population aging as much as changes in underlying disease risk,” said Russell.
The incidence of the disease, when measured on an age-standardised basis, has declined, with US data showing age-specific dementia prevalence rates dropping by two-thirds between 1984 and 2024, the report noted, citing recent academic studies.
Improvements in some of the risk factors that are thought to cause Alzheimer’s, such as reduced smoking and improved education, may have contributed to that.
Even some anomalies in the data may belie optimistic nuances. For instance, better reporting of dementia on death certificates is thought to be behind a rise in dementia-related mortality in the US, the report said.
High incidence rates recorded in East Asia, however, aren’t as easily explainable.
There is better understanding of the risk factors associated with Alzheimer’s too, offering pathways to reducing infection.
Sufferers’ immune systems and their levels of chronic inflammation are now thought to be strong “causal mechanisms”. And the impacts of variations in apolipoprotein E (APOE) genes are also better understood, making targeted treatment possible.
It is also thought that almost half of dementia cases could be reduced if a list of 14 risk factors – including hearing and sight loss, depression, hypertension and obesity – were “eliminated via lifestyle changes or population-based policy changes”, the report added, citing other studies.
Advances in diagnostic tests has made it possible for doctors to identify the likely onset of the disease earlier and more accurately, the report stated. These include blood-based biomarkers and finger-prick tests.
This “could materially influence underwriting, anti-selection risk, and long-term claims patterns”, the authors, who also comprised Hilary Henly, Global Medical Researcher, Global R&D at RGA, wrote.
On the treatment side, studies indicate that vaccines for shingles and some other conditions have been found to substantially reduce the chances of developing dementia by countering “inflammatory or viral triggers that contribute to cognitive decline”.
And despite a setback in tests on the efficacy of treating Alzheimer’s with glucagon-like peptide (GLP)-1 receptor agonists – medications that are being used by diabetics and also to lower obesity – they are still thought to provide some protection against its onset.
Emerging improvements in detection and greater understanding of the disease’s progression may be unlikely to halt what the report says is a sharp rise in the anticipated number of deaths associated with Alzheimer’s over the next decade; by the mid-2030s, a larger proportion of the population than ever will enter their advanced years, when dementia is more prevalent.
Also, worsening environmental hazards among the main risk factors – including air pollution – are more likely as the impacts of climate change intensify.
The best hope for making a substantial impact on the incidence of Alzheimer’s would be an accurate diagnostic blood test that could be given to the young and asymptomatic individuals exposed to key risk factors.
“In short, wide access to an accurate blood test for AD diagnosis could be transformative,” the report concluded.
So where does this all lead for actuaries?
The report said they will be expected to track “the fast-moving landscape of Alzheimer’s disease” and incorporate new developments into their “pricing, product design, and reserve assumptions”.
“Actuaries will not take raw Alzheimer’s trend data at face value,” said Russell.
“With the support of medical and research experts, they will work to separate the underlying disease dynamics from administrative and diagnostic artefacts and then project data and trends forward using appropriate models.”
While advances in detection and treatment won’t make life easier for actuaries just yet, they do indicate that progress is being made in reducing anguish and suffering for people who contract Alzheimer’s disease.
For instance, the report said that early diagnosis could improve the ability of younger people to take out life insurance.
“Early diagnosis expands the window during which patients may benefit from therapies that reduce symptoms or slow disease progression. This shift alone could significantly decrease disease progression and Alzheimer’s mortality trends in future,” the report said.
And even if the benefits are not seen in actuarial reports, they will be felt in sufferers’ lives.
“Alzheimer’s disease trends will be especially important for long-term care and critical illness, not just mortality and longevity,” Russell said.
