If people would just do four things -- engage in regular physical activity, eat a healthy diet, not smoke and avoid becoming obese -- they could slash their risk of diabetes, heart attack, stroke or cancer by 80%, a new report has found.
But less than 10% of the 23,153 people in the multiyear study -- published in Monday's Archives of Internal Medicine -- actually lived their lives this way.
"The study has such a simple straightforward focus on making the point that prevention works in preventing serious disease," said Dr. J. Leonard Lichtenfeld, deputy chief medical officer for the American Cancer Society.
"What really has been difficult is trying to figure out how to get people to take notice of the message and engage in healthy behaviors."
Researchers at the U.S. Centers for Disease Control and Prevention and in Germany examined the habits of German men and women ages 35 to 65 from 1994 and 1998. At the start of the study, the scientists measured participants' heights and weights and asked them about their diseases, lifestyle habits and diets.
Healthy factors included never smoking; engaging in physical activity for at least 3 1/2 hours each week; eating a diet low in red meat and high in fruits and vegetables; and having a body mass index lower than 30. (A person with a BMI of 30 or above is classed as obese.)
About 9% of participants practiced all four healthy lifestyle choices.
Four percent practiced none.
Roughly 35% followed two of the healthy practices.
Researchers reviewed participants' medical records about eight years later, on average, looking for diabetes, heart attacks, strokes or cancer. People who followed all four healthy practices were at far lower risk compared with people who followed none: 93% lower risk for diabetes, 81% for a heart attack, 50% for a stroke and 36% for cancer.
For people who had never smoked and who maintained a BMI under 30, the risk of chronic disease was reduced 72% -- the most dramatic reduction of any dual combination of healthy factors.
The scientists also found that each healthy factor reduced chronic disease risk.
A BMI under 30 lowered overall disease risk most -- particularly for diabetes.
Never smoking reduced heart attack risk the most of all four factors.
"All of them are important, and trying to pick one is like asking someone to pick their favorite child," said study coauthor Dr. Earl S. Ford, a senior scientist in the CDC's Division of Nutrition, Physical Activity and Obesity.
Dr. Vyshali S. Rao, chairwoman of cardiology at Huntington Hospital in Pasadena and an American Heart Assn. spokeswoman, said the study underscores that shifting to a healthier diet helps the heart even if a person remains overweight.
However, she said, people who alter their diets often find they lose weight as a side benefit.
"Cardiologists try to stress to their patients more and more [that] cardiovascular disease is in hands of each individual patient to change," Rao added.
The study's findings, which are consistent with investigations that started in the late 1990s, are likely to apply to people living in the United States as well as those in Germany.
"The strongest reductions in risk for diabetes and [heart attack] are not surprising," said Dr. Rachel Ballard-Barbash, associate director of the National Cancer Institute's Applied Research program. "Even within a few years' time, we can see changes in these diseases associated with these health behaviors," such as lowered levels of LDL cholesterol and blood pressure.
"For stroke and cancer," she added, "most studies would suggest it would take longer to see changes."
Heart disease, cancer and strokes are the top three causes of death in the United States, killing an estimated 1,328,643 people every year, according to the CDC. Diabetes is the sixth cause of death, killing 72,449 annually. Many additional people live constrained lives in poor health because of these illnesses.