> ... exactly what caused the decrease in cardiovascular disease deaths but would love to hear if others do.

Unfortunately I don't have data either, but I do have a hypothesis that may or may not end up surviving scrutiny when the relevant data becomes available. If someone can refute these ideas, please contribute.

The ultimate cause: demographics changed.

The recent decades have seen native populations reduce their fertility in the US. This is analogous to ecological succession of pioneering species colonizing barren land building up new soils by quickly flourishing and in turn crowded out in competition as other species take hold in niches opened by the pioneers laying a rich framework however being unsuccessful at sustaining dominance due to the energetic and fitness costs of extreme adaptation in resource poor environments that are unable to be useful traits relative to other species that can quickly capitalize on existing infrastructure when there's no need to divert capacity to build anew when resources become abundant. Today when applied to populations of humans in the US, the same principal goes under names like "white flight" as fleeing urbanization to recreate past conditions that were more favorable in competition strategies, "gentrification" when enclaves of urban areas decay and are then susceptible to recolonization efforts, and "immigration" to relieve bottlenecks in reproduction and the resulting scar of exposed barren land and poor nutrient circulation in the ecosystem that are caused by pioneer individuals stockpiling reserves without reinvesting in reseeding efforts.

Heart disease is typically a progressive terminal stage of diabetes and other metabolic disorders that intertwine risk factors such as poor nutrition, excessive calorie consumption and resulting unhealthy body fat percentages, alcohol abuse, cigarette use, and high stress. Looking closure at the medical literature, I'd actually reconsider the idea that statins produce beneficial health outcomes, but I won't get into that in this comment.

The point here is that in heart disease being the cumulative effects over a lifetime and diabetes as a _leading_ (not trailing) indicator of population risk for heart disease, what you're really seeing is the transition of health since WW2 when war rationing forced the agricultural and food processing industries to change course in providing massive amount of calories at low cost and effective propaganda and marketing to ensure sustained demand when the war was over to not shock the economy back into depression. Heavily processed foods like spam, American cheese, and canned/dried foods are technological means to make food supplies go further with less waste and higher caloric density. Add in things like pushing cigarette consumption heavily after the war and you get the perfect storm that kills off a large percentage of the lower class baby boomer generation early in life by around the 1980s. What's left since then are the middle and upper class baby boomers whose children reproduce in far lower numbers, being replaced with immigrants. Those immigrants come here with very different cultures regarding food consumption, nutrition, and healthcare that for a period of time did decrease the incidence of influence of the cultural epidemic of war-era food technology.

Usually after one generation though, immigrant families transition to the already establish cultural expectations and shift dietary and consumption patterns. Therefore you get the next surge of diabetes as the form of the next incarnation of the cycle. In a few decades you'll see another recurrance in more prevelent heart disease.