Bladder problems seen more often among smokers than nonsmokers may be further motivation for women to quit smoking, a new study suggests.
Looking at 2,000 Finnish women ages 18 to 79, researchers found that smokers were three times as likely to say they frequently had to urinate -- with fewer than two hours between trips to the bathroom.
They were also almost three times as likely to report urgency. That means frequently feeling that you need to get to a bathroom quickly -- a problem often diagnosed as overactive bladder.
There was no clear link between smoking and the risk of having so-called urge incontinence, in which actual leakage follows a sudden, strong urge to urinate.
But that may be because too few women in the study had urge incontinence to be able to detect a connection to smoking, according to senior researcher Dr. Kari A. O. Tikkinen, of McMaster University in Ontario, Canada.
The findings, reported in the journal Obstetrics & Gynecology, do not prove that smoking, itself, causes bladder problems.
But there are already plenty of reasons to quit smoking, or never start, Tikkinen noted in an interview.
If you smoke, definitely you should try to quit, he said. This is one more potential reason.
The findings are based on questionnaires mailed to 3,000 women randomly chosen from a population register. Of the 2,000 who responded, seven percent reported frequent urination, while 10 percent reported urgency.
In addition, 11 percent had stress incontinence, the most common form of urinary incontinence, in which leakage happens when there's pressure on the bladder -- from things like exercise, heavy lifting or coughing. Another three percent of the women had urge incontinence.
Among current smokers (one-quarter of the group), between 10 percent and 15 percent reported frequency or urgency. When the researchers weighed other factors that affect the risk of bladder symptoms -- like age, body weight and childbirth -- current smokers were about three times as likely as non-smokers to have frequency or urgency.
There are reasons that smoking could directly affect those symptoms, according to Tikkinen. Based on animal research, nicotine may trigger excessive bladder muscle contractions. And over time, smoking may damage nerve function in the bladder.
Smokers did not, however, have a higher risk of incontinence, either the stress or urge types.
Tikkinen said the finding on urge incontinence should be interpreted cautiously; smokers did have a higher risk of the problem, but the difference was not significant in statistical terms.
As for stress incontinence, Tikkinen said it's not surprising there was no link. Some past studies have reached the same conclusion, he noted. And it may be that the underlying causes of stress incontinence -- like physical changes caused by childbirth or menopause -- are more important than nicotine's potential effects.
So will kicking the smoking habit improve bladder symptoms like frequency and urgency? There have yet to be clinical trials to answer that question, according to Tikkinen.
But, he said, everybody knows that smoking is harmful. So you should try to quit.
The link to bladder symptoms, Tikkinen noted, might get more young smokers to consider quitting.
Well-known risks, such as lung cancer and heart disease, can seem like distant threats to young people, he pointed out. But bladder symptoms, you can get when you're young.
SOURCE: bit.ly/nTyvNV Obstetrics & Gynecology, September 2011.