Nov. 9, 2009 -- Long-term use of a neti pot to clear stuffy noses and blocked nasal passages may actually encourage more sinus problems rather than keep them away.

A new study shows people who used nasal saline irrigation for a year and then discontinued use the following year had 62% fewer cases of sinusitis in the year that they didn't use the device.

Neti pots have become increasingly popular in recent years for the treatment of sinus infections and other forms of sinus disease. The pots deliver a stream of sterile saline solution to the nasal passages to loosen and clear nasal congestion.

Researchers say despite the common use of nasal saline irrigation to treat sinusitis, there has been little scientific research to confirm its effectiveness. Sinusitis is an inflammation or infection of the sinuses and nasal passages that can cause headache or pressure in the eyes, nose, and cheek area as well as nasal congestion, cough, and fever.

The study, presented this week at the American College of Allergy, Asthma and Immunology (ACAAI) Annual Meeting in Miami, followed 68 people who used nasal saline irrigation for 12 months and then discontinued use for another 12 months.

The results showed that the number of cases of sinusitis decreased by 62.5% during the discontinuation phase. Researchers also compared the rates of sinusitis among those who stopped using nasal saline irrigation and another group of 24 adults who used daily nasal saline irrigation for 12 months. Again, they found sinusitis among daily users was significantly higher (50%) than among nonusers.

Researchers say nasal mucus acts as a first line of defense against infections, and long-term nasal saline irrigation may interfere with this natural immune function.

Although use of a neti pot for nasal saline irrigation may temporarily improve sinus infection symptoms, they say "its daily long-term use may result in an increased frequency of acute [sinusitis] by potentially depleting the nose of its immune blanket of mucus," write researcher Talal M. Nzouli, MD, of Washington, D.C., and colleagues in their study.