We have known for many years that genetics is the biggest influences on longevity. Most of the scientific studies have suggested that our genes account for about 20 to 25 percent of how long we live.

A new study from Israel suggests that the effects might be even higher. There are two kinds of factors affecting how long we live.

Some of those are what are known as intrinsic factors. These include most of the diseases we see occurring as people age.

There are also extrinsic factors. These include deaths from accidents. They include deaths from infectious disease not related to aging. They include deaths from factors such as gun violence.

The study looked at about 100 years of twin data from three large studies in Scandinavia. In the early years of the studies, medicine and safety were not as good as it was in the later years. Therefore, more people died from extrinsic factors.

In the later years, the intrinsic factors became more important. That was because other factors improved. Seat belts would be an example. Antibiotics and vaccines would be another example.

We have long known that individuals who live to the age of 100 often have relatives that do likewise. Therefore, they manifest a strong genetic component to their extended life span.

Once the authors were able to eliminate the extrinsic factors, the data suggested that 50 percent of our expected life span is genetic in origin.This opens the doorway to multiple new avenues of research. That is made even more possible now that we have deciphered the human genome.

In addition to conducting more research, there are other opportunities for information that could be obtained.

A genetic evaluation early in life might help predict an individual’s longevity. It might show diseases they are prone to getting before those diseases actually show up.

The human genome is going to affect a lot of things that we do in the future of medicine. I have told my grandchildren heading to college that pharmacogenomics is the wave of the future.

People will be able to go to the physician for treatment of a disease. There may be multiple medications that could be used. Hypertension is a good example. The patient’s genetic makeup will then tell the doctor which of the potential medications will provide the most benefits with the fewest side effects.

Longevity is now felt to be 50 percent affected by genetics. This is just the tip of the iceberg. Many more studies in this area will follow in the coming years.

Addendum – There have been two deaths in unvaccinated children in the Pennsylvania measles outbreak this year. Last year there were three deaths in the Texas outbreak. Those five deaths compare to a total of three deaths total for the previous 24 years. 2015 was the last year with a measles death prior to the 2025 Texas epidemic.