By Dr. Dave Hnida

(CBS4) – For close to a century, heart disease has been the No. 1 cause of death in America. But a new study out of the CDC shows that cancer will soon be the leader.

As of 2014, cancer has passed heart disease and is the leading cause of death in 22 states including Colorado. In the year 2000, it was the leading cause in only two states.

So what’s going on?

Researchers are not sure, but believe better prevention and treatment of heart problems are responsible for a better cardiac outlook. But with cancer it’s not quite the same story.

Sure, cancer treatments continue to improve, and screening has gotten better, but the aging of our population — as well as the habits of our population — are behind the shift in cancer overtaking heart disease as the leader.

Many people think that heredity is to blame for cancer deaths, but that’s simply not the case. In fact, it’s believed that genetics play a major role in only 5-10% of cases. The rest is on us (although we certainly can’t control aging).

For example, obesity is a known cancer risk factor, and you know how America’s waistline continues to expand.

In the big picture, the top cancer causers include tobacco, alcohol, obesity, lack of exercise, a diet with too much fried and fatty foods, as well as environmental causes.

So when you look at that list, you realize that heredity is not destiny, and most of us do have some measure of control over whether cancer strikes us. Now that doesn’t mean that if you develop cancer, it’s your fault. Far from it. But you probably have more control than you think.

The estimated total deaths from cancer in the U.S. this year is expected to pass more than 600,000. And that 22 states will certainly grow each year.

So take care of what you can take care of—control what you can control. When you think about it, that will not only lower your risk of a deadly cancer, but heart disease and other diseases as well.

As a side note, the number one cause of death in America before 1910 was infectious diseases, but thanks to antibiotics and vaccines (when we get them), that cause has dropped down the list.

Dr. Dave Hnida is CBS4’s Medical Editor. He blogs about the latest studies and trends in the health world. Read his latest blog entries, check out his bio or follow him on Twitter @drdavehnida