末梢動脈疾患の傾向（Abstract # 3449）

無症候性末梢動脈疾患の有病率は着実に増加しているようである

Prevalence of asymptomatic peripheral artery disease appears to be steadily increasing

米国成人における無症候性末梢動脈疾患の有病率は着実に増加しているようである、と2007年American Heart Association学会で発表された。研究者らは1999～2004年に施行された米国国内の3つの詳細な調査を通して集計されたデータを解析した。これらの調査では、足関節上腕血圧比（ankle-brachial blood pressure index）0.9未満を末梢動脈疾患と定義した。ベースライン時に心血管疾患歴のない40歳以上の5,376人において、有病率は1999～2000年には3.7%であったものが2001～2002年には4.2%、2003～2004年には4.6%に増加した。有病率は70歳以上の最高齢グループにおいて最も高かったが、各々のサブグループ（40～49歳、50～69歳、70歳以上）において一つの期間から次の期間へ移行するごとに有病率は増加した。このデータから心血管疾患として知られる肥満、糖尿病、および高血圧の有病率も同様に増加していることが確認された。

The prevalence of asymptomatic peripheral artery disease appears to be steadily increasing among American adults, according to a presentation at the annual meeting of the American Heart Association.

“We were interested in seeing if the prevalence of peripheral artery disease in the general U.S. population is increasing, specifically among people who do not have known coronary artery disease,” said Andrew D. Sumner, MD, lead author of the study and medical director of the Heart Station and Cardiac Prevention at Lehigh Valley Hospital in Allentown, PA.

Researchers hypothesized that the prevalence of asymptomatic peripheral disease is increasing and that the increase is associated with a rise in the prevalence of other common cardiovascular risk factors, including diabetes, smoking, obesity and hypertension.

Sumner and colleagues analyzed data from three successive National Health and Nutrition Examination Surveys (NHANES), conducted in two-year increments between 1999 and 2004, finding a case of peripheral artery disease by identifying people with an ankle-brachial index of less than 0.9.

Sumner explained, “The ankle-brachial index measures the ratio of the blood pressure in the arms and legs, and if it is less than 0.9, people by definition have peripheral artier disease.”

The researchers then examined the prevalence of associated cardiac risk factors of obesity, diabetes, hypertension and smoking in 5,376 participants, age 40 years and older with no prior history of cardiovascular disease.

They found that prevalence among asymptomatic adults 40 years and older significantly increased from 3.7 percent in the 1999-2000 survey to 4.2 percent in the 2001-02 survey and 4.6 percent in the 2003-04 survey.

“Peripheral artery disease prevalence was highest among those age 70 and older,” Sumner said. “But there also was an increase in the prevalence in each adult age group, including 40 to 49, 50 to 69 and greater than 70 years.”

The authors said prevalence of obesity, diabetes, hypertension and smoking also increased over these three surveys.

“Peripheral artery disease is affecting more people in the United States and will continue to do so because the prevalence of this problem increases as we get older, and we have an aging population,” Sumner said. “And this increase is associated with an increase in common cardiac risk factors.”