Heart Disease, Cancer, Stroke, Alzheimer's, and Diabetes would be an easy top 5. Covid was the third leading cause of death last year, and considering the effects on some, it likely deserves more work as well.

source: https://www.cdc.gov/nchs/fastats/leading-causes-of-death.htm

Senescence is the primary one, by a large margin.

I’d add obesity, and depression/anxiety to that list

Obesity can 100% be prevented and/or reversed. It’s not a medical problem but a cultural one.

Respectfully I disagree and science seems to be supporting that point of view as well.

But, even if you call it a cultural issue, it is still a health issue. It causes billions in additional care, shortens lifespans, is a risk factor for many other diseases. Those facts alone make it a medical problem.

What if the same is true for Alzheimer's? We just don't know yet.

You left out the biggest killer: heart disease.

That and covid deaths and a big chunk of cancer are all caused by obesity