Cosmetic breast implants do not increase the overall risk of cancer, a Swedish study has found.

American researchers studied 3,486 Swedish women who underwent cosmetic surgery for breast implants between 1965 and 1993 and were followed until the end of 2002.

Data was obtained from the Swedish Cancer Registry, which reports on cancer occurrence for the entire country.

The research team identified 180 cancer cases in women with breast implants, fewer than the 193.1 predicted to occur in the population.

Cosmetic implants were not associated with an increased risk of cancer overall, the study found.

Women with implants had an increased incidence of lung cancer (20 cases observed, 9.1 cases expected) and a decreased incidence of breast cancer (53 cases observed, 71.9 cases expected) compared with the general population.

According to the researchers, these results likely reflect the lifestyles and smoking habits of the women in the study rather than an effect of the implants themselves.

Lead researcher Joseph McLaughlin, of the International Epidemiology Institute in Rockville, said: "After an average follow-up of 18 years, and a maximum follow-up of 37 years, we found that women who have undergone breast implantation have a reduced risk for breast cancer, most likely due to differences in lifestyle or reproductive characteristics.

"We also found no increased risk for brain cancer or for lymphoma, sarcoma, or multiple myeloma."

Previous studies have found no consistent link between cosmetic implants and an increased risk of developing cancer.

The study is published in the Journal of the National Cancer Institute.