20-30% of lifespan is based on genetics and 20-30% of health in later years as well. The rest is all lifestyle.

This is controlling for external elements like accidents or disasters.

So somewhat genetics is true but it can be overcome with lifestyle to some degree. Figuring out which lifestyle choices is tricky and one of those times where sciences' replication crisis makes it all muddled.

Advancement in medicine also plays a role because it can reign in some poor lifestyle choices that were death spirals just a generation prior.