Women who experience early menopause may have an increased risk of developing bladder cancer, especially if they are smokers, a new study has found.

Bladder cancer is the 6th most common cancer diagnosed in Europe, with around 27,000 European women diagnosed every year.

European and US researchers studied the medical history of over 220,000 nurses who had been taking part in health studies since 1976. They found that those who went into menopause before the age of 45 were 45% more likely to develop bladder cancer than those who went into menopause after the age of 50.

Furthermore, if the women smoked, they were 53% more likely to develop bladder cancer.

The average age of women at menopause is 51 years in developed countries, but around one in 20 women go into menopause before the age of 45.

According to the researchers, ‘smoking remains the most important risk factor for bladder cancer'.

"This study indicates that earlier age at menopause seems to increase the risk of bladder cancer. Our primary interpretation is that a factor like smoking, which is known to correlate with earlier age at menopause, remains of grave concern as the main cause of bladder cancer. It reinforces the warning that smoking really is harmful in ways that we might not have easily imagined," commented lead researcher, Dr Mohammad Abufaraj, of the University of Vienna.

He added that the findings indicate that it is ‘unlikely' that females factors, such as age when periods begin, number of pregnancies, oral contraceptive use or the use of hormone replacement therapy are associated with bladder cancer risk.

Previous research by the same team has shown that smoking worsens bladder cancer outcomes. Those who smoke tend to have a poorer response to treatment and higher mortality rates. However, 10 years after stopping smoking, these risks return to the same level as a non-smoker.

Details of these findings were presented at the recent European Association of Urology congress in Barcelona.