The study found no correlation between the development of brain tumors and how frequently mobile phones were used or the length of use. Nor did the study find any evidence that brain tumors were more likely to occur on the side of the head most used with cellphones.

The findings are consistent with other studies, Dr. Christoffer Johansen of the Danish Cancer Society, said in a statement. Johansen was one of the study's authors.

"These results are in line with other large studies on this question, including a recently published large-scale, population-based study by the Swedish Interphone Study Group," Johansen said. "There have been a few studies that found an increased risk of brain tumors with cellphone use, but those studies have been criticized for problems with the study design."

A 2002 study, for instance, found some indication that long-time users of analog cellphones had a greater tendency to develop a specific type of tumor on the side of the head most often used for making calls.

Johansen cautioned that the new study covered very few people who regularly used cellphones for more than 10 years.

"In our study, few people reported regular cellphone use for 10 years or more," Johansen said. "We won't be able to make any firm conclusions until we can confirm these results with studies with more long-term and heavy cell phone users."

Despite the findings, using a hands-free system for cellphone use will eliminate any dangers, Johansen said.