The researchers investigated the relationship between post-menopausal hormone replacement therapy (HRT) and gallbladder cancer risk.
They published their findings in the International Journal of Cancer.
Women above 45 years of age were included in the study.
The research, funded by the Italian Association for Cancer Research, included data from a case-control study conducted in Italy between 1985 and 1997.
| HRT increases risk of gallbladder cancer by more than 3-fold.
| International Journal of Cancer |
A total of 31 incident, histologically-confirmed cases of gallbladder cancer were identified.
A further 3702 controls, in hospital for acute, non-neoplastic conditions, were included in the trial.
The team found that the multivariate odds ratio (OR) was 3.2 for those who had ever used HRT.
Furthermore, the OR tended to rise with longer duration of therapy.
Author Silvano Gallus, of the Mario Negri Institute for Pharmacological Research, Milan, Italy, concluded on behalf of the group, "Although based on small numbers, due to the rarity of the disease, these findings provide the first direct epidemiological evidence of an association between HRT and gallbladder cancer."