The increasingly large number of older adults who develop moderate or severe valve disease as a result of aging is becoming a clinical and public health concern in many developed countries, according to an article published online by Lancet.

The research done by investigators from the Mayo Clinic estimates that about 5 million adult Americans have moderate or severe heart valve disease as a consequence of aging, a switch in demographics from the first half of the twentieth century, which saw valve disease in younger individuals due to rheumatic fever.

“Valve diseases are a significant public health concern because the proportion of our elderly population is increasing,” says Vuyisile Nkomo, MD, cardiologist and lead author of the study. “This study shows that valve diseases increase significantly with aging. It is a major step in understanding the scope of the burden of valve diseases today and their contribution to declining health with aging.”

The current research is the first comprehensive study to look at data from the general population and the community. Data from the general population reveals information on systematic samples of individuals to reveal trends; data from the community -- in this case, Olmsted County, where the Mayo Clinic is based -- provides information on people who have already been offered clinical attention for an illness.

Researchers used data from echocardiograms from the general population of 11,911 participants in three National Heart, Lung and Blood Institute-funded population studies: the Coronary Artery Risk Development in Young Adults (CARDIA) Study, the Atherosclerosis Risk in Communities (ARIC) Study, and the Cardiovascular Health Study (CHS). Researchers also analyzed data from Olmsted County of adults who had been assessed by clinically indicated echocardiograms.

In the general population studies, the prevalence of adults diagnosed with moderate or severe valve disease increased with age, from 0.7 percent in 18- to 44-year-olds to 13.3 percent in those 75 years and older. The projected national estimate of valve disease based on the age and gender distribution of the 2000 U.S. population census is 2.5 percent of adults, approximately 5 million people.

In Olmsted County, 1.8 percent (adjusted to U.S. census figures) of adults were diagnosed with valve disease and the prevalence also increased with age, from 0.3 percent in the 18- to 44-year-olds to 11.7 percent of those 75 and older.

emarkably, the prevalence of valve disease was similar in the population but in the community, valve disease was diagnosed less in women, suggesting a possible gender bias and need for further study, according to Nkomo.

“The results of this study are not trivial. We predict -- in view of the growth and aging of the population -- that the number of U.S. patients with valve disease will double in the next 20 years,” said co-author Maurice Enriquez-Sarano, MD, also a Mayo Clinic cardiologist.

Nkomo noted that the trend toward older patients has an impact on decision-making, particularly regarding surgery: “When physicians diagnose valve disease in the elderly, we hesitate to perform surgery because of the risks involved.”

However, the authors wrote that research shows that cardiac surgery for valve disease has much improved, particularly in the elderly, said Enriquez-Sarano, pointing to an article published by the same group in the July 17 issue of Circulation.

While elderly patients undergoing valve surgery have higher risks, they benefited from surgery as much as younger patients, and operative risks in elderly patients over the 16-year study period declined considerably, said Enriquez-Sarano.

“We hope our data will generate further research to unravel why some people get valve diseases with aging and some others do not,” he said. “Also, while we are raising concerns about the re-emergence of valve diseases, there are outstanding established treatments and tremendous efforts to find less invasive ways to treat valve diseases and bring about new treatments so we can prolong and improve the quality of life of patients affected by valve diseases.”