- MONDAY, May 5 (HealthDay News) — Children who wet their beds
frequently have elevated levels of a heart hormone that helps regulate
levels of fluid around the heart, a new study finds.

Additionally, children who habitually snore are about three times as
likely to wet the bed as children who don't snore, but the severity of
snoring appears to have little effect on the risk of bed-wetting,
according to the research, which is published in the May issue of
Pediatrics.

“Our findings were really an eye-opener,” said study co-author Dr.
David Gozal, director of the division of pediatric sleep medicine at the
University of Louisville, in Kentucky. “Why children with bed-wetting have
high levels of this hormone; that will require a bit more research.”

About 9 percent of boys and 6 percent of girls at age 7 have trouble
sleeping through the night without wetting the bed, according to the U.S.
National Institutes of Health. The problem — which affects about 5
million American children — runs strongly in families. Nighttime
bed-wetting, which is also called enuresis, is not the fault of the child
or parent. For some reason, the child's brain isn't responding to normal
cues to wake up and empty the bladder.

Because so many children who snore seem to also wet the bed, Gozal and
his colleagues wanted to investigate the connection between the two
problems.

The researchers reviewed almost 18,000 surveys completed by parents of
5- to 7-year-old children to see how many were habitual snorers or had
problems with enuresis. From that group, they found that 1,976
children — about 11 percent — were habitual snorers. Fifty-three
percent of those with habitual snoring were boys. About 27 percent of that
group also wet the bed. Nearly 90 percent of those who wet the bed were
boys. Among non-snoring children, just 11.6 percent wet the bed. As with
the snoring group, almost 90 percent of those with enuresis were boys.

“The risk of bed-wetting for children who snore was about threefold,”
said Gozal.

But, the researchers also found that the severity of snoring didn't
appear to change the risk of bed-wetting when they examined a smaller
group of 60 children who wet the bed during sleep lab studies. Twenty of
the children had obstructive sleep apnea; 20 had habitual snoring but no
sleep apnea, and 20 didn't snore at all.

The researchers did find that levels of a heart hormone, brain
natriuretic peptide (BNP), were raised in children who wet the bed. That
finding would seem to be related to snoring, according to Gozal, because
snoring causes the upper airways to contract, which makes the chest
muscles work harder to pull in air, which in turn creates pressure on the
airways and blood vessels, which causes blood to return to and dilate the
heart. Then, too much fluid collects and needs to be released, which is
one of BNP's functions — to increase sodium and water excretion around
the heart.

However, if snoring was responsible for the elevated BNP levels, a more
serious snoring problem should have caused even higher levels of BNP, but
that wasn't the case.

“Clearly, this is a complex mix,” said Gozal.

What parents need to know from this study is that if your child is
predisposed to bed-wetting, any additional factors, such a snoring, may
make bed-wetting more likely. So, if your child snores and wets the bed,
Gozal said that treating the snoring may help reduce bed-wetting.

“This is a great study, and it's nice to see some of the science behind
the problem,” said Dr. Sangeeta Chakravorty, clinical director of the
pediatric sleep program at Children's Hospital of Pittsburgh.

“Parents should know that 15 percent of children get better every year
with no intervention,” she said, but added, if bed-wetting persists after
a child is 5 years old and it happens more than three times a week, you
should mention it to your child's doctor at the next well visit.

More information

To learn more about enuresis, visit the American Academy of Family Physicians.