WASHINGTON -- What's a healthful lifestyle worth? Maybe six to 10 extra years of life, new research suggests.
Dramatic benefits are shown for people who don't smoke and who maintain low cholesterol and blood pressure levels.
The research, appearing Wednesday in the Journal of the American Medical Association, found life-extending benefits for adults of all ages who have low heart disease risk factors, including not smoking cigarettes.
Dr. Jeremiah Stamler of Northwestern University, lead author of the study, said it evaluated more than 366,000 people over many years and determined the health outcome for people who were considered at low risk of heart disease.
The results, he said, show that an American lifestyle that includes smoking, little exercise, obesity and poor diet "creates havoc in the cardiovascular system," while healthy habits can extend life substantially.
"Low-risk people in our country are rare birds," Stamler said at a news conference Tuesday. "That reflects our lifestyle."
The study, he said, marks the first time data have been collected for how low-risk people's health develops over a period of years.
Ending what some call an epidemic of coronary and cardiovascular diseases will require a greater effort to get people to adopt healthy life habits, Stamler said. "For upcoming generations, this means encouraging favorable behaviors beginning in early childhood in regard to eating, drinking, exercising and smoking," the study says.
The JAMA report analyzes health outcomes from a group of women and four groups of men who participated in two long-term studies. Participants ranged in age from 18 to 59. The health of two groups was monitored for 16 years, the other three for 22 years.
For any in the groups who died, researchers determined the cause of death, then related this outcome to basic health measurements taken at the beginning of the studies.
The researchers found that death from all causes and from cardiovascular disease was substantially reduced among those with low heart disease risk factors, defined as those who did not smoke and who had total cholesterol readings of 200 milligrams per deciliter or below and blood pressure readings less than or equal to 120 over 80. Less than 10 percent of the patients were in this "low-risk" category.
One study, called the Multiple Risk Factor Intervention Trial screened the health of 342,000 men between the ages of 35 and 57 in the mid-1970s.
At the end of 16 years, the study found that the MRFIT men in the "low-risk" category who started the study between 35 years to 39 years of age had an increased life expectancy of 6.3 years, while those between ages 40 to 57 at the start had a 5.9-year increase in life expectancy.
The risk of death from any cause was 50 percent to 55 percent lower for those in the "low-risk" category, the study found.
Another study, called the Chicago Heart Association Detection Project, or CHA, evaluated health outcomes for 10,025 men between ages 18 and 39, 7,490 men between 40 and 59 and 6,229 women between ages 40 and 59 years.
It found that the younger men in the "low-risk" category had a life expectancy 9« years longer than other men in the group their same age. For men aged 40 to 59 years, life expectancy was extended by 6 years, the study found.
For women in the "low-risk" category, life was extended by 5.8 years.
The risk of death from all causes in the CHA study was reduced by 57 percent to 58 percent for the nonsmoking men with good cholesterol and blood pressure readings. For such "low-risk" women, there was a 40 percent lower risk of death for any cause.
"Lifestyle ... clearly influences who will fall into the low risk-factor group," said the study. It noted that since the 1960s, there has been a general health recommendation to decrease fat consumption, increase exercise, eat a diet balanced with fruits and vegetables, and to avoid smoking, excess alcohol and excess weight.