Smoking risk: Early menopause increases the risk of bladder cancer

Early menopause increases the risk of bladder cancer for smokers – this was the finding of an interdisciplinary research group, led by urologist Mohammad Abufaraj from MedUni Vienna's Department of Urology and Division of Epidemiology and other international university hospitals, using data from 230,000 participants in the longitudinal Nurses' Health Studies I and II. Hormonal factors have no influence on the incidence of the disease but smokers who start the menopause before the age of 45 run a more than 50 percent higher risk of developing it. The results of the, as yet unpublished, study were recently presented at the European Association of Urology (EAU) Congress in Barcelona.

In Austria, approximately 1,600 people a year develop bladder cancer (BCA), men being approximately four times more likely to be affected than women. That said, the mortality rate is around 40 percent higher in women. The reasons for this gender difference are unclear.

The original question of the study conducted by a research group led by urologist Mohammad Abufaraj from MedUni Vienna's Department of Urology and researchers from the Division of Epidemiology at MedUni Vienna's Center for Public Health and scientists from Harvard Medical School and other hospitals was to establish the significant risk factors for women. The team explored whether hormonal processes in the female body play a role in the development of bladder cancer. To do this they analysed data from the longitudinal Nurses' Health Study that has been running since 1976, and the Nurses' Health Study II." "

The Nurses' Health Study is the largest women's health study in the world and has produced important findings relating to nutrition and cancer risks by means of questionnaires and clinical examinations of women. Initially, nurses were explicitly invited to participate, since they have an above-average level of medical knowledge. The participants are surveyed every two years about contraception, diet and lifestyle habits.

Over the observation period, the study team has now found 629 cases of bladder cancer and compared the data of women who started the menopause after the age of 50 with those of women who started the change before the age of 45. What stood out was that women who had an early menopause were more likely to have developed bladder cancer. It was statistically determined that women who smoked – who often experience an early menopause as a result of smoking – have a 53 percent higher risk of developing the disease.

Abufaraj says, "Our data also showed that factors such as the age when periods began, the number of pregnancies, use of oral contraceptives or hormone replacement therapy do not increase the risk of bladder cancer."