"If I were a ranch, they would have named me Bar-Nothing" (Rita Hayworth); "Just one more thing" (Pete Falk); and "Book him, Danno" (Jack Lord).

Those may be unforgettable lines from three early film and TV stars, but they faded from memory when all three suffered from dementia before they passed away.

Although more than 5 million people in the United States contend with dementia today, the good news is that the rates are declining.

The Framingham Study recently revealed a 44 percent drop in dementia incidence since the late 1970s. And a new JAMA Internal Medicine study found that the rate declined by 24 percent from 2002 to 2012.

It looks like better heart health may be one reason dementia rates are falling.

For instance, people are taking statins and reducing their intake of red meat (still too high, but down from more than 130 pounds per person annually to 106) and sugary sodas (down 25 percent).

How can you get in on this trend?

1. Keep your mind challenged and stay socially connected. Take a class; volunteer; learn a new language; play the game Double-Decision (it increases your brain's processing speed and has been shown to cut the risk for dementia by 48 percent over 10 years).

2. Keep your cardiovascular system in tip-top shape: Ask your doc about taking a daily low-dose aspirin and a statin if you have stubborn elevated levels of LDL cholesterol; take sugar and syrups, any refined grain and all trans and most sat fats off your plate; walk 10,000 steps a day or the equivalent; and don't smoke! It works.