Age, obesity, high cholesterol, and high triglyceride measurements in midlife predict not only heart disease risks, but also the likelihood of erectile dysfunction decades later, according to a new study in the April 21, 2004 issue of the Journal of the American College of Cardiology.
“Patients may be more inclined to use lipid-lowering medications if they can prevent erectile dysfunction, as well as heart disease. Now researchers should include erectile dysfunction as an outcome in trials of statin drugs,” said corresponding author Elizabeth Barrett-Connor, MD, from the University of California in San Diego.
The researchers traced men who had participated in a heart disease risk study in the mid-1970s and asked them to fill out a standard questionnaire on erectile function, known as the International Index of Erectile Function (IIEF-5). Between 1972 and 1974, 82 percent of the adult residents of Rancho Bernardo, Calif. participated in a survey of coronary heart disease risk factors. The participants, who were age 30 to 69 at the time, underwent a baseline clinical evaluation that included a brief medical and medication history and measurement of height, weight, blood pressure, fasting plasma glucose, cholesterol, and triglyceride levels.
Of the 1,810 men who had taken part in the original study, researchers sent surveys to 944 men who were still living in 1998. Their analysis was based on 570 surveys that were returned with complete answers to the erectile function questions.
Mean age, body mass index, cholesterol, and triglycerides were each significantly associated with an increased risk of erectile dysfunction. Cigarette smoking was marginally more common in those with severe or complete erectile dysfunction, as compared with those without erectile dysfunction. Blood pressure and fasting blood glucose were not significantly associated with erectile dysfunction. The authors wrote that the lack of association was probably due to higher death rates among men with higher blood pressure or blood sugar levels.
Dr. Barrett-Connor noted that most studies have looked just at snapshots of current risk factor measurements and erectile dysfunction, and many have used different ways of assessing erectile dysfunction.
“The Rancho Bernardo Study is a prospective study of community-dwelling men with a long follow up, from midlife to old age. In addition, the original researchers used excellent quality coronary heart disease risk factors for the baseline measurements. Another strength of this analysis is that we used a widely accepted international standard for rating erectile function,” Dr. Barrett-Connor said.
Not surprisingly, the men who were still alive and returned the follow-up mailed survey appeared to be those who were healthier 25 years ago, i.e. those with more favorable baseline risk factor measurements. The authors wrote that this “[s]urvival bias does not negate the relevance of the results, because it is the survivors who live long enough to develop ED [erectile dysfunction].” This effect may also explain the weak association between smoking and erectile dysfunction. Almost all of the surviving men had never smoked or had quit smoking.
Melvin D. Cheitlin, MD, MACC from San Francisco General Hospital and the University of California, San Francisco, who was the guest editor for this article, called it “a very significant paper.” He said the long-term follow-up offered information not available from most other studies of the issue.
“This is a unique study, in that it started in asymptomatic people without known coronary disease, looked at their risk factors, and then 25 years later looked at the same population, or at least whoever was left alive,” Dr. Cheitlin said.
Dr. Cheitlin said the study is limited by the measurements that were available in the 1970s, and he noted that Rancho Bernardo residents who took part were almost all white. Still, he agreed that the authors’ conclusions are reasonable, including the advice that erectile dysfunction should be considered a warning sign of coronary heart disease and vice-versa.
The American College of Cardiology, a 29,000-member nonprofit professional medical society and teaching institution, is dedicated to fostering optimal cardiovascular care and disease prevention through professional education, promotion of research, leadership in the development of standards and guidelines, and the formulation of health care policy.