NEW YORK (Reuters Health) - Young adults who have several risk factors for heart disease may start to show problems in their arteries by the time they're in their 40s, a new study shows.

Researchers found that among more than 3,000 African American and white men and women, those with more heart disease risk factors in their 20s were two to three times more likely to have calcium build-up in their arteries 15 years later.

Calcium is a component of the artery-clogging plaques that lead to coronary heart disease. CT scans can be used to detect calcium in the arteries, and the extent of calcification has been shown to predict a person's risk of future heart attack.

The new findings, reported in the Journal of the American College of Cardiology, suggest that even an 18-year-old's cholesterol and blood pressure matter.

"As this study illustrates, we are learning more and more about the beginnings of heart disease and how to prevent it," lead study author Dr. Catherine M. Loria, a researcher at the National Heart, Lung and Blood Institute, Bethesda, Maryland, said in a statement.

"Young men and women should work with their doctors to learn about their risk, and then do everything they can to reduce it, such as eating a healthy diet and being physically active," she added.

The findings are based on data from 3,043 adults who were between the ages of 18 and 30 in 1985-86. At study entry and periodically thereafter, the study participants were assessed for various heart disease risk factors, including high cholesterol, high blood pressure and smoking.

They also underwent CT scans to detect coronary artery calcium 15 years after the start of the study, when they were between the ages of 33 and 45.

Overall, Loria's team found that nearly 10 percent showed calcium build-up in their arteries, with participants in their 40s at higher risk than those in their 30s. When the researchers looked at other risk factors for coronary calcium, they found that blood pressure, cholesterol and smoking in young adulthood were key.

For every 10 cigarettes participants smoked per day in early adulthood, their risk of coronary calcium buildup later in life rose by 50 percent. The risk also climbed in tandem with their blood pressure, LDL ("bad") cholesterol and blood sugar levels.

The findings show that even young adults need to be paying attention to their heart disease risk, according to Loria and her colleagues.

It's recommended that all adults have their blood pressure checked every two years, and their cholesterol measured regularly starting at age 20. Blood sugar should be measured starting at age 45, or earlier for people at increased risk of diabetes.

In general, experts advise all adults to avoid smoking, exercise at least 30 minutes a day, and eat a diet low in sodium, saturated fat and trans fats to lower their risk of heart disease.