Today's Globe: smoking ban, obese children, heart failure, C. difficile, stents and drug risk, Down syndrome aging, Googling flu, Ronald Davis

Nearly 600 fewer Massachusetts residents have died from heart attacks each year since legislators banned smoking in virtually all restaurants, bars, and other workplaces four years ago, according to a report to be released today that provides some of the strongest evidence yet that such laws save lives.

Obese children as young as 10 had the arteries of 45-year-olds and other heart abnormalities that greatly raise their risk of heart disease, say doctors who used ultrasound tests to take a peek inside.

Exercise can do a lot of good for most people, but it apparently isn't much help to those with heart failure.

The sometimes deadly bacterium Clostridium difficile is at least six times more common than previously believed, researchers said yesterday, based on a survey of hundreds of US hospitals.

Stent patients who take the blood thinner Plavix along with certain heartburn drugs may face a greater risk of heart attack, stroke, and other dangerous events, according to a study released yesterday.

The life expectancy of people with Down syndrome has increased from about 25 years in 1983 to more than 50, meaning this is the first generation that will probably outlive their parents.

A lot of ailing Americans enter phrases like "flu symptoms" into Google and other search engines before they call the doctor. That simple act, multiplied across millions of keyboards in homes around the country, has given rise to a new early-warning system for fast-spreading flu outbreaks called Google Flu Trends.

Ronald M. Davis, a former president of the American Medical Association who campaigned against tobacco, alcohol, obesity, illicit drugs, and unhealthy lifestyles in his career as a public health official, died Thursday at his home in East Lansing, Mich. He was 52. The cause was pancreatic cancer. Dr. Davis received the diagnosis in February and had since helped to raise public awareness of the disease, which afflicts 37,000 Americans a year and kills 34,000.