By Ben Harder
Special to The Washington Post
Tuesday, March 13, 2007
There are plenty of reasons for men to keep their hearts healthy, but one hits below the belt: Our sex lives may depend on it. More than one in six men nationwide says he sometimes or always has difficulty with erections, according to a study published last month in the American Journal of Medicine. And poor cardiovascular health is often to blame.
Another way of viewing the problem is that more than 18 million U.S. men older than 20 have erectile dysfunction, or ED -- at least according to one definition. (More on that in a moment.)
"In an earlier era, [ED] was thought to be more of a psychological issue than a physical one," said Elizabeth Selvin, the Johns Hopkins University epidemiologist who led the new study involving about 2,100 men selected to form a cross section of male America. "We're realizing now that a huge proportion of ED cases reflect vascular disease."
Urologist Christopher S. Saigal of the University of California at Los Angeles, who reported a similar frequency in a separate study published last year in the Archives of Internal Medicine, agreed, saying, "ED is a manifestation of what's happening in the rest of the cardiovascular system."
Together, the two studies provide the most comprehensive look to date on the prevalence of ED. Indirectly, the studies also offer further evidence that lifestyle changes, such as weight loss, regular exercise and smoking cessation, may offer an alternative to drug treatment.
In the normal male sexual response, sensory or mental stimulation causes blood to fill the corpora cavernosa, a pair of tubular structures that run the length of the penis. The relaxing of smooth muscle tissue helps trap blood in the organ, sustaining an erection.
Normal aging is thought to play a role in ED, perhaps by helping to make tissues less efficient in transporting blood. Of men 70 and older, 70 percent report having erectile dysfunction, compared with just 5 percent of 20- to 39-year-old men, Selvin found in her study.
Other problems can compound the effects of age: Alcohol abuse, certain drugs (many antidepressants, antihistamines and blood pressure medications) and nerve damage from prostate surgery, for example, can all interfere with erections.
But ED is most often linked to such risk factors for heart disease as smoking, diabetes, obesity, high blood pressure and high cholesterol.
"A lot of these conditions affect the circulation, particularly in the penis," limiting blood flow to the organ, said Arthur L. Burnett, a urologist at the Johns Hopkins University School of Medicine who collaborated with Selvin on her study.
Half of diabetic men, for example, have erectile dysfunction, according to both the Hopkins researchers and Saigal's earlier work. At any age, sedentary men are two to four times as likely to have ED as more physically active men.
Past studies that explored the prevalence of erectile dysfunction yielded estimates ranging from 8 percent (in a 1999 study of men age 18 to 59) to 52 percent (in a 1994 study of Massachusetts men age 40 and older), Selvin noted. Inconsistencies in how different studies have defined ED account for some of this variation.
Selvin's and Saigal's studies counted a man as having erectile dysfunction if he said he was "sometimes able" or "never able" to get and keep an erection adequate for satisfactory intercourse. By contrast, the Massachusetts study also counted men who said they were "usually able" to get such an erection. Other studies have used more idiosyncratic tests, for instance, asking men to rate their sexual performance on a scale from good to very poor, and counting answers of "poor" and "very poor" as evidence of ED.
There is no diagnostic test for ED -- doctors identify the problem mainly through patient descriptions of their symptoms -- and therefore there is no universal definition.
Selvin says her 18 percent estimate is buttressed by the fact that 91 percent of the men who were asked about their erections answered the question. That unusually high rate means that any bias in sampling isn't likely to have misrepresented the actual prevalence of ED. Most previous studies, especially those that predated the debut of sildenafil citrate (Viagra) in March 1998, have had lower response rates. For example, the Massachusetts study interviewed men in the late 1980s, before Viagra ad campaigns had increased public awareness, renamed the problem (casting it in a more mechanical -- and treatable -- light) and made men more willing to talk about it.
In 1985, ED -- or impotence, as it was then known -- accounted for 7.7 doctor office visits per 1,000 U.S. men, according to the National Ambulatory Medical Care Survey. By 1999 -- a year after Viagra's debut -- that rate had nearly tripled, to 22.3. Competing drugs vardenafil hydrochloride (Levitra) and tadalafil (Cialis) arrived in 2003. In 2005, the most recent year for which data are available, the three drugs generated a combined $1.3 billion in revenue.
Allen D. Seftel, a urology professor at Case Western Reserve University in Cleveland, said the new study's 18 percent figure understates the scope of the problem. Seftel, who has conducted several studies on the causes and treatment of ED, said he sees many patients, particularly relatively young men, who feel their erections are adequate for sex, though marginally so. While "they're distraught because their erections are going south," he said, they might be "always able" or "usually able" to produce an erection.
Thus misled, researchers "are missing out on a group of individuals who are a little bit younger and may have an earlier stage of disease," he said. "That's an important population because you can potentially avoid long-term consequences by intervening now."
Manufacturer-funded studies suggest that Viagra, Cialis and Levitra help 60 to 70 percent of the time, said Seftel. "But these oral drugs are sort of a stop-gap measure," said Seftel, who has received consulting fees from the manufacturers. "They're not going to correct the underlying disease process." Seftel said men who are dissatisfied with their erections often "need to do something to get their cardiovascular health back in sync." Saigal agreed: "If they're smoking, they need to stop." If they're out of shape, he added, they should lose weight and be more active.
In a study published last summer in the Journal of Urology, men age 40 to 75 who were most physically active were about 30 percent less likely to develop erectile dysfunction over the next 14 years than were peers who were mostly sedentary. "An active lifestyle is really protective," said Selvin.
Conversely, "men who reported watching TV and videos or using computers outside of work for more than three hours per day were much more likely to have ED" -- roughly three times as much -- than others, she said.
Some research suggests lifestyle changes -- a healthier diet, weight loss, smoking cessation and regular exercise -- can even relieve ED.
In a two-year Italian study published in 2004 in the Journal of the American Medical Association, obese men with ED who adopted better fitness habits -- boosting their average physical activity from less than an hour a week to more than three hours -- experienced improved erectile function. They lost weight, too.
But drugmakers are skeptical that healthier habits can fully reverse the vascular disease processes that cause impotence.
"Lowering your cholesterol or treating your high blood pressure, getting your blood sugar under control or losing weight . . . I advocate for [all] that, but it's not going to cure ED," said Shontelle Dodson, senior medical director of Pfizer, which makes Viagra. "There's no data to show that if you modify those risk factors, and you already have erectile dysfunction established, that you will no longer have erectile dysfunction."
But at least for relatively healthy men, doctors are realizing, the prospect of improved sex may better motivate us lethargic, noncompliant, bad-habit-laden beasts to move than past entreaties to lead heart-healthy lifestyles.
Seftel predicted a "paradigm shift" in which erectile dysfunction becomes a sentinel sign of potential threats to the cardiovascular system. Men with ED should be tested for related problems such as high cholesterol and high blood pressure; for those who test positive, medications combined with lifestyle changes might yield manifold benefits, he said.
After all, said Saigal, "things that are good for your heart are going to be good for your sex life." ·
Ben Harder is acting editor of sciencenews.org and sciencenewsforkids.org. Comments:email@example.com.