That's not what I meant. A solid answer as to why those conditions are happening, not the fact that they are happening at all.
We have research on what can affect heart health, like what things might be linked to it, such as smoking and alcohol. We also know genetics plays a huge role.
So we don't actually have solid answers, actionable answers as to the rise of heart health issues. Look at this analysis[1] regarding how dietary guidelines specifically for fats (saturated, trans) have very little substantial evidence supporting it. Yet this gets repeated by the average person, that fats are the ultimate evil you must avoid. In another study[2] we find that reducing your fat intake still resulted in the same rates of mortality as those who ate more. This is also why more in the space are shifting away from these sort of claims ("only eat x amount of saturated fat per day") and more to general food composition (eg who cares if a fish has saturated fats, eat the fish with vegetables).
It's quite challenging to figure out, everyone has their theories. All I'm saying is we don't actually have the answers yet.
[1]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9794145/
[2]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8092457/