Genetics and longevity

Human longevity is influenced by genetics, environment, lifestyle, healthcare and chance. There is no single gene — or genetic test — that can tell an individual how long they will live.

Genetics can nevertheless contribute useful evidence about biological processes associated with ageing, disease susceptibility and survival.

Lifespan and healthspan

Two related ideas are important.

Lifespan describes how long a person lives.

Healthspan describes the period of life spent in relatively good health and functional independence.

For long-term financial planning, both can matter. A longer lifespan may increase the period over which retirement assets need to support spending. Changes in healthspan may also affect healthcare costs, care requirements, work capacity and financial independence.

APOE

APOE encodes apolipoprotein E, which is involved in lipid transport and other biological processes.

Its common alleles — usually described as ε2, ε3 and ε4 — have been extensively studied.

APOE ε4 is associated with increased susceptibility to late-onset Alzheimer's disease and also has relationships with lipid metabolism and cardiovascular biology. APOE ε2 can have different associations.

An APOE result is not a diagnosis.

Many people carrying an ε4 allele never develop Alzheimer's disease, while many people without ε4 do. Age, other genes, cardiovascular health, lifestyle and numerous environmental factors also matter.

For Bioanalytix, APOE illustrates an important principle:

genetic evidence may change the distribution of risk without determining an individual's outcome.

FOXO3

FOXO3 is involved in cellular stress responses, metabolism, repair processes and other pathways relevant to ageing.

Variants around FOXO3 have repeatedly been associated with exceptional longevity in multiple human populations.

These findings make FOXO3 an important longevity-research gene, but they do not turn it into a lifespan clock. Individual variants generally contribute only part of a much larger biological and environmental picture.

Longevity is polygenic

Most variation in human longevity cannot be explained by one or two genes.

Many genetic variants may each contribute small effects, interacting with:

• cardiovascular and metabolic health;
• inflammation;
• immune function;
• cancer susceptibility;
• neurological health;
• lifestyle;
• environmental exposure; and
• other genetic factors.

This is why Bioanalytix treats longevity as a range of uncertainty rather than a genetically determined number.

Why this matters financially

A traditional financial model may assume retirement lasts to a particular age.

But the financial consequences of living to 80, 90, 100 or beyond can be very different.

Longer scenarios may affect:

• the duration of retirement spending;
• portfolio sustainability;
• withdrawal rates;
• exposure to inflation;
• healthcare and aged-care requirements;
• insurance decisions;
• the value of maintaining growth assets;
• timing of wealth transfers; and
• the eventual estate.

Bioanalytix uses biological evidence to help make this uncertainty visible.

The purpose is not to predict lifespan.

It is to ask whether a financial plan remains resilient across a wider and better-informed range of possible futures.