Irish researchers discover potential link between smoking and male impotence

The cause-and-effect relationships between smoking and conditions such as lung cancer and heart disease are established. But what about smoking and male impotence?

A 2001 investigation in the journal Preventive Medicine evaluated 19 studies that reported the smoking habits of 3,819 impotent men. It found that “40 per cent of impotent men were current smokers, compared with 28 per cent of men in the general population”, concluding that “tobacco use is an important risk factor for impotence”.

And in 2004 the British Medical Association suggested that the effects of smoking on erectile dysfunction (ED) were mediated through smoking-related blood vessel damage.

Now, in a unique Irish study “Can smoking cause impotence? A radiological retrospective cohort study comparing internal pudendal artery calcification on CT in male smokers versus non-smokers” – researchers investigating the blood supply to the male genitalia have discovered “a potential further association between smoking and ED, which has not been previously discussed, studied, or acknowledged by the tobacco industry”.

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What prompted the study?

Lead author Dr Emma Tong is clinical fellow in interventional radiology at Dublin's Beaumont Hospital and senior lecturer for the Royal College of Surgeons in Ireland. Dr Tong told The Irish Times: "Smoking causes vascular calcification, which promotes end organ disease/damage. For example, calcified coronary arteries can cause a heart attack. Similarly, calcified blood vessels supplying the brain can often lead to stroke.

“This is well established in the literature, and among the public. What is neither well studied nor well publicised is the potential link between smoking, and vascular calcification of the blood vessels supplying the male genitalia, which can potentially lead to ED.

"This is what we investigated. Co-author Prof William Torreggiani of Tallaght University Hospital, where the study was undertaken, had a brain wave – is the link between smoking and vascular calcification of the male genitalia apparent in computed tomography [CT] scans?"

Dr Tong and colleagues reviewed data from 100 men in Ireland (aged between 40 and 60 years) and compared the CT scans of 50 smokers versus 50 non-smokers.

“We gave each patient a score from zero to 10,” explained Dr Tong, “based on how heavily calcified their blood vessels were, paying specific attention to the internal pudendal artery (IPA), the main artery supplying the penis. Zero represented healthy vessels with no arterial vascular calcification, and 10 represented severely diseased vessels with maximal calcification.

“12 per cent of patients in non-smoking group had IPA calcification, whereas 50 per cent in the smoking group had IPA calcification – more than a four-fold increase.”

This novel study, Dr Tong and colleagues state, demonstrates “a strong and statistically significant increase in the rate of IPA calcification in smokers, as compared to non-smokers, with an inferred indirect association with ED.”

Consistent findings

A spokesperson for the Health Service Executive (HSE) explained that Dr Tong and colleagues' findings "are consistent with other research ," noting that "in 2014 the landmark United States Surgeon General's Report found that the evidence is sufficient to infer a causal relationship between smoking and ED."

Dr Paul Kavanagh, of the HSE's Tobacco Free Ireland Programme said : "This study is a reminder that smoking has a wide range of effects on health – including ED – and these effects are not limited to older people who have smoked all their lives. For any smoker, reaching out to access good stop-smoking care is the single best step they can take to tackle that risk."

Given that the risk spectrum includes ED and male impotence, the researchers suggest that young to middle-aged men should be made more aware of this potential risk, with Dr Tong observing that “young people are immune to the photos and information provided in anti-smoking campaigns regarding lung cancer and heart disease etc. but this is something novel and eye-catching which might help deter young people from smoking or provide a stimulus to stop.”

Dr Kavanagh provides a statistical context which might boost such a stimulus: “The scale of harm caused by smoking is staggering,” he says, “and each week in Ireland more than 100 people die and more than 1,000 are hospitalised for disease caused by smoking.

The HSE can help on Quit.ie or by telephoning 1800 201 203. Good stop-smoking care – combining support from a stop smoking advisor with a safe and effective stop smoking medicine – maximises the chances of becoming smoke-free.”

Stop-smoking agencies

Dr Tong suggests that her team’s findings “would be something interesting for stop-smoking agencies to focus on, and a novel method for anti-smoking campaigns.”

Considering future research, Dr Tong and colleagues would like to see a study being undertaken “that looks at a population of men with known impotence and assesses both their smoking history and degree of vascular calcification.”

Interestingly, a Chinese study published in 2014 investigated the potential association between quantity and duration of smoking and the risk of ED – Association of Quantity and Duration of Smoking with Erectile Dysfunction: A Dose-Response-Analysis – finding that "the risk of ED for an increment of 10 cigarettes smoked per day and 10 years of smoking was increased by 14 per cent and 15 per cent, respectively. In other words, quantity and duration of smoking were both positively associated with the risk of ED."

What about E-cigarettes? A recent US study considered the effect of electronic nicotine delivery devices (ENDS) on ED – Association of E-Cigarettes With Erectile Dysfunction: The Population Assessment of Tobacco and Health Study. The researchers concluded that using ENDS "seems to be associated with ED independent of age, cardiovascular disease, and other risk factors," suggesting that "While ENDS remain under evaluation for harm reduction and smoking-cessation potential, ENDS users should be informed about the possible association between ENDS use and ED."

The evident relationship between smoking and male impotence, already under scrutiny for many years, has now acquired a sharper focus thanks to the work of Dr Tong and colleagues.