BOSTON -- In Tuesday's medical news, NewsCenter 5's Heather Unruh reported on a possible explanation for sleep problems, a link between attention problems in children and smoking and another reason to eat fish.

Sleeping Problems

Allergies may be to blame for poor sleep, researchers said.

A study published in the Archives of Internal Medicine examined almost 600 French women and men and found the worse their allergy symptoms, the worse their sleep.

The allergy sufferers had more insomnia, woke up more in middle of night, snored more and felt tired during the day. Allergy sufferers also took longer to fall asleep.

Fatty Fish

Eating more fatty fish, like salmon and tuna, may help prevent kidney cancer in women, according to new research.

A new study in the Journal of the American Medical Association found women who ate fish with Omega-3 fatty acids every week lowered their risk of getting kidney cancer 44 percent to 74 percent compared to women who did not.

Doctors have said before that there are many benefits to eating fatty fish. The American Heart Association recommends we eat two servings of dark, oily fish each week for a healthy heart.

ADHD And Smoking

New research found a possible link between cases of attention deficit hyperactivity disorder in children and environmental toxins.

Chicago researchers said about one-third of the children with ADHD had mothers who smoked during pregnancy or were exposed to lead during childhood.

Researchers also said children whose mothers smoked were two and a half times more likely to be diagnosed with ADHD.

Some experts are questioning whether this study rings true. They point to the fact that smoking is down, but ADHD in children is up.

The study was published in the Journal Environmental Health Perspectives.